Uplink synchronization method and apparatus, ground terminal, device, medium and program product

Abstract

The application provides an uplink synchronization method and device, a ground terminal, equipment, a medium and a program product. The uplink synchronization method comprises: after initial downlink synchronization is completed, periodically receiving a synchronization signal block and measuring a downlink time offset measurement value corresponding to each synchronization signal block; extracting a crystal oscillator time offset component and a Doppler residual time offset component from the downlink time offset measurement value corresponding to a target synchronization signal block; and before sending an uplink signal, performing uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component. The above scheme periodically receives a synchronization signal block and splits its downlink time offset measurement value into a crystal oscillator time offset component and a Doppler residual time offset component, so that the above uplink synchronization method can accurately identify timing errors of two different sources in real time on the terminal side, reduces error accumulation, and is beneficial to improving the time synchronization accuracy of the above uplink synchronization method.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and more specifically, to an uplink synchronization method, apparatus, ground terminal, device, medium, and program product. Background Technology

[0002] In wireless communication systems, the relative movement between the transmitting and receiving ends generates the Doppler effect, leading to frequency offset and time-domain variations (dynamic time offset) during signal transmission. Doppler time offset originates from changes in the distance along the signal propagation path, and its rate of change depends on the relative speed. Crystal oscillator time offset, on the other hand, is caused by the frequency deviation of the local crystal oscillator at the transmitting and receiving ends, and typically varies linearly with time. Traditional methods primarily estimate and correct the frequency offset introduced by the Doppler effect in low- to medium-speed scenarios. In high-speed scenarios (such as satellite communication, where the satellite's speed relative to the ground terminal can reach 7 km / s), the Doppler effect not only causes frequency offset but also leads to significant time-domain compression or stretching.

[0003] Most related technologies rely on the terminal to periodically receive ephemeris information and use an ephemeris prediction module to pre-compensate for uplink and downlink timing offsets during the intervals between receptions. However, because the downlink residual timing offset measurement cannot distinguish between Doppler residual timing offset and crystal oscillator timing offset, the terminal can only compensate in a single direction when adjusting uplink timing. This results in uplink timing offsets being doubled within one SSB cycle, and this error accumulates over time, potentially leading to uplink synchronization failure. Summary of the Invention

[0004] The purpose of this application is to provide an uplink synchronization method, apparatus, ground terminal, device, medium, and program product to solve the above-mentioned problems.

[0005] In a first aspect, embodiments of this application provide an uplink synchronization method, the method comprising: after completing initial downlink synchronization, periodically receiving synchronization signal blocks and measuring downlink time offset measurements corresponding to each synchronization signal block; extracting crystal oscillator time offset components and Doppler residual time offset components from the downlink time offset measurements corresponding to a target synchronization signal block; and performing uplink residual time offset compensation based on the crystal oscillator time offset components and the Doppler residual time offset components before transmitting an uplink signal.

[0006] In the implementation of the above scheme, by periodically receiving synchronization signal blocks and splitting their downlink time offset measurements into crystal oscillator time offset components and Doppler residual time offset components, the uplink synchronization method can identify timing errors from two different sources in real time and accurately at the terminal side, reducing error accumulation and improving the time synchronization accuracy of the uplink synchronization method. On the other hand, uplink residual time offset compensation can be completed before uplink signal transmission, allowing the terminal to immediately correct the uplink transmission time without waiting for additional network feedback or external calibration signals, reducing synchronization delay and improving link real-time performance and communication system throughput. Furthermore, the uplink synchronization method relies on local measurement and calculation at the terminal, reducing the need for high-precision hardware, simplifying hardware design, reducing terminal costs, and enhancing the adaptability of the uplink synchronization method to different environments, thus improving its overall adaptability.

[0007] In one implementation of the first aspect, extracting the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block includes: determining the target synchronization signal block and a plurality of downlink time offset measurements corresponding to a predetermined number of consecutive synchronization signal blocks preceding the target synchronization signal block; determining the crystal oscillator time offset change rate of the crystal oscillator time offset component based on the plurality of downlink time offset measurements; determining the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate; and determining the Doppler residual time offset component based on the downlink time offset measurement value of the target synchronization signal block and the crystal oscillator time offset component.

[0008] In the implementation of the above scheme, based on the characteristic that the crystal oscillator time offset changes linearly with time, the crystal oscillator time offset change rate is determined by analyzing the downlink time offset measurements of the target synchronization signal block and multiple previous synchronization signal blocks. This allows for the accurate extraction of the crystal oscillator time offset component corresponding to the target synchronization signal block, making the separation of the crystal oscillator time offset and Doppler residual time offset more precise, which is beneficial to improving the time synchronization accuracy of the above time synchronization method. On the other hand, based on the crystal oscillator time offset change rate and the total downlink time offset measurement of the target synchronization signal block, the Doppler residual time offset component corresponding to the target synchronization signal block can be accurately calculated, providing a precise basis for subsequent uplink compensation. Furthermore, by extracting the crystal oscillator time offset component and the Doppler residual component before sending the next synchronization signal block and performing uplink residual time offset compensation, the above uplink synchronization method can compensate for the uplink residual time offset in real time and efficiently, reducing synchronization delay and enhancing the stability and reliability of the communication system.

[0009] In one implementation of the first aspect, determining the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on a plurality of downlink time offset measurements includes: averaging the plurality of downlink time offset measurements to determine the crystal oscillator time offset rate of change of the crystal oscillator time offset component.

[0010] In the implementation of the above scheme, based on the zero-mean characteristic of Doppler residual time offset, averaging multiple downlink time offset measurements can effectively reduce the impact of Doppler residual time offset on crystal oscillator time offset, enabling the above uplink synchronization method to stably and accurately determine the crystal oscillator time offset change rate, thereby improving the time synchronization accuracy of the above uplink synchronization method; on the other hand, the averaging operation is simple and easy to implement, has low computational resource requirements, and can quickly obtain the crystal oscillator time offset change rate, which is beneficial to improving the real-time performance of the above uplink synchronization method.

[0011] In one implementation of the first aspect, determining the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on multiple downlink time offset measurements includes: performing linear fitting on the multiple downlink time offset measurements to obtain a fitting relationship between the multiple downlink time offset measurements and time; and determining the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on the slope in the fitting relationship.

[0012] In the implementation of the above scheme, by linearly fitting multiple downlink time offset measurements, the trend of time offset change over time can be clearly captured, thereby more accurately determining the crystal oscillator time offset change rate and avoiding interference from short-term fluctuations. On the other hand, the slope of the fitting relationship directly corresponds to the crystal oscillator time offset change rate. This calculation method based on a physical model not only improves the accuracy of determining the crystal oscillator time offset change rate but also enhances the interpretability of the results. Furthermore, linear fitting is a common mathematical tool that is easy to implement and computationally efficient, enabling it to run quickly on the terminal. This is beneficial for improving the timeliness and effectiveness of the uplink synchronization method for compensating for uplink residual time offset.

[0013] In one implementation of the first aspect, the method further includes: acquiring a target signal synchronization block at each interval of uplink compensation preset period.

[0014] In the implementation of the above scheme, the target signal synchronization block is acquired at each uplink compensation preset period to achieve periodic compensation for the uplink residual time offset. Each compensation can closely match the actual communication situation at the most recent time, which is beneficial to improving the time synchronization accuracy of the above uplink synchronization. On the one hand, this method of periodically acquiring the target signal synchronization block helps to detect and adapt to changes in the communication environment in a timely manner, which is beneficial to improving the adaptability and reliability of the above uplink synchronization method. On the other hand, by setting an appropriate preset period, a balance can be achieved between compensation accuracy and system resource consumption, so as to achieve timely compensation without increasing unnecessary resource overhead due to acquiring synchronization blocks too frequently.

[0015] In one implementation of the first aspect, determining the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate includes: determining the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate and the uplink compensation preset period.

[0016] In the implementation of the above scheme, by combining the crystal oscillator time offset rate with the uplink compensation preset period to determine the crystal oscillator time offset component, the actual needs of uplink compensation can be matched more accurately. This not only takes into account the long-term drift characteristics of the crystal oscillator, but also matches the periodicity of uplink compensation, which is conducive to improving the time synchronization accuracy of the above uplink synchronization method. On the other hand, adjusting the calculation of the crystal oscillator time offset component according to the preset period can ensure that the compensation action matches the timing requirements of the communication system, thereby improving communication efficiency. Furthermore, determining the crystal oscillator time offset component in combination with the preset period helps to maintain the consistency and stability of compensation under different environmental conditions, thereby improving the reliability of the compensation effect.

[0017] In one implementation of the first aspect, the method of performing uplink residual time offset compensation based on the crystal oscillator time offset component is as follows: based on the crystal oscillator time offset component, the uplink residual time offset component is compensated in the same direction as the time offset direction of the crystal oscillator time offset component. In the implementation of the above scheme, by compensating the crystal oscillator time offset component according to its time offset direction, the cumulative error caused by the crystal oscillator can be accurately corrected, the uplink transmission time can be accurately aligned, and the risk of loss of synchronization caused by error superposition can be effectively reduced. On the other hand, by specifically compensating the crystal oscillator time offset component, the uplink can be made more stable, which is conducive to improving the synchronization effect of the above uplink synchronization method.

[0018] In one implementation of the first aspect, the uplink residual time offset compensation based on the Doppler residual time offset component is performed as follows: based on the Doppler residual time offset component, the uplink residual time offset compensation is performed on the Doppler residual time offset component in a direction opposite to the time offset direction of the Doppler residual time offset component.

[0019] In the implementation of the above scheme, by compensating for the Doppler residual time offset component in the opposite direction, the time offset caused by the relative motion of the satellite can be effectively offset, so that the uplink signal can adapt to the path change in advance or delay, which is beneficial to improving the adaptability of the above uplink synchronization method. On the other hand, by specifically compensating for the Doppler residual time offset component, the uplink can be made more stable, which is beneficial to improving the synchronization effect of the above uplink synchronization method.

[0020] Secondly, according to an embodiment of this application, an uplink synchronization device includes: The downlink time offset measurement acquisition module is used to periodically receive synchronization signal blocks and measure the downlink time offset measurement value corresponding to each synchronization signal block after the initial downlink synchronization is completed. The component extraction module is used to extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block; The uplink compensation module is used to perform uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component before sending the uplink signal.

[0021] Thirdly, embodiments of this application provide a ground terminal, including a baseband processor, wherein: The baseband processor is configured to periodically receive synchronization signal blocks and measure the downlink time offset measurement value corresponding to each synchronization signal block after completing the initial downlink synchronization; extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block; and perform uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component before transmitting the uplink signal.

[0022] Fourthly, embodiments of this application provide an electronic device, including: a processor, a memory, and a communication bus, wherein the processor and the memory communicate with each other through the communication bus; the memory stores computer program instructions that can be executed by the processor, and the computer program instructions are read and executed by the processor to perform the method provided in the first aspect or any possible implementation of the first aspect.

[0023] Fifthly, embodiments of this application provide a computer-readable storage medium storing computer program instructions, which, when read and executed by a processor, perform the method provided in the first aspect or any possible implementation thereof.

[0024] In a sixth aspect, embodiments of this application provide a computer program product, the computer program product including a computer program, which, when executed by a processor, implements the method provided by the first aspect or any possible implementation of the first aspect.

[0025] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a multi-beam mobile satellite communication system provided in an embodiment of this application; Figure 2 A flowchart illustrating the uplink synchronization method provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of the uplink synchronization device provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application.

[0029] Crystal oscillator time offset is a systematic deviation in time reference caused by the inconsistency in nominal frequencies between the crystal oscillators at the transmitting and receiving ends. This offset manifests as the difference between the absolute time perceived by the receiver and the actual transmission time at the transmitter, and accumulates linearly with continued communication. The rate of change of crystal oscillator time offset depends on the frequency difference between the two crystal oscillators. The rate of change of crystal oscillator time offset remains essentially constant over time scales of seconds, minutes, and even hours. Therefore, crystal oscillator time offset increases or decreases at an approximately uniform rate, with its direction and magnitude depending on which crystal oscillator has a higher frequency. Because the accumulation rate of crystal oscillator time offset is stable, it can be identified and compensated individually through long-term statistical averaging, and it does not change with external propagation environment or relative motion.

[0030] The Doppler effect refers to the phenomenon where the frequency measured by the receiver differs from the actual transmission frequency of the wave source when there is relative motion between the source and receiver. Generally, the received frequency increases as the two sources move closer and decreases as they move further apart. In low-to-medium speed communication scenarios, the relative speed between the transmitter and receiver is typically only tens to hundreds of kilometers per hour, resulting in a small Doppler frequency shift, often only tens to hundreds of hertz, far less than the carrier bandwidth. In this case, the time-domain stretching (time offset) of the signal is negligible and can be ignored within a symbol period; therefore, the system only needs to compensate for the frequency offset to ensure demodulation performance. However, in high-speed scenarios, such as low-Earth orbit satellite communication, the satellite's speed relative to the ground terminal can reach 7 km / s, resulting in a Doppler frequency shift of tens of kilohertz or even higher, accompanied by significant dynamic time offset: the signal is compressed or stretched in the time domain, potentially accumulating tens of nanoseconds or even larger time-domain offsets within a symbol period. This time offset changes rapidly over time; if only frequency offset compensation is used, inter-symbol interference and timing drift will accumulate rapidly, leading to demodulation failure. Therefore, high-speed scenarios must simultaneously address both frequency offset and time offset, making traditional methods that only compensate for frequency offset no longer applicable.

[0031] In view of this, the embodiments of this application provide an uplink synchronization method. By periodically receiving synchronization signal blocks and splitting its downlink time offset measurement value into crystal oscillator time offset component and Doppler residual time offset component, the uplink synchronization method can identify timing errors from two different sources in real time and accurately at the terminal side, reducing error accumulation and improving the time synchronization accuracy of the uplink synchronization method. On the other hand, uplink residual time offset compensation can be completed before uplink signal transmission, so that the terminal can immediately correct the uplink transmission time without waiting for additional network feedback or external calibration signals, reducing synchronization delay and improving link real-time performance and communication system throughput. Furthermore, the uplink synchronization method relies on local measurement and calculation at the terminal, reducing the need for high-precision hardware, simplifying hardware design, reducing terminal cost, and enhancing the adaptability of the uplink synchronization method to different environments, thus improving the adaptability of the uplink synchronization method.

[0032] Before introducing the above uplink synchronization methods, let's first introduce their application scenarios: The technical solution of this application can be applied to non-terrestrial network (NTN) systems such as satellite communication systems and high-altitude platform station (HAPS) communication, for example, integrated communication and navigation (ICaN) systems and global navigation satellite systems (GNSS).

[0033] Satellite communication systems can be integrated with traditional mobile communication systems. For example, mobile communication systems can be fourth-generation (4G) communication systems (e.g., Long Term Evolution (LTE) systems), Worldwide Interoperability for Microwave Access (WiMAX) communication systems, fifth-generation (5G) communication systems (e.g., New Radio (NR) systems), and future mobile communication systems.

[0034] Please see Figure 1 , Figure 1 This is a schematic diagram of a multi-beam mobile satellite communication system applicable to embodiments of this application. For example... Figure 1 As shown, the satellite provides communication services to terminal devices through multiple beams. In this scenario, the satellite is a non-geostationary earth orbit (NGEO) satellite connected to core network equipment. The satellite uses multiple beams to cover the service area, and different beams can communicate through one or more of time division, frequency division, and space division. The satellite provides communication and navigation services to terminal devices by broadcasting communication and navigation signals. The satellite mentioned in this embodiment can also be a satellite base station or network-side equipment mounted on a satellite.

[0035] For example, satellite communication systems can be categorized into three types based on their orbital altitude: Geostationary Earth Orbit (GEO) satellite communication systems, also known as synchronous orbit satellite communication systems; Medium Earth Orbit (MEO) satellite communication systems; and Low Earth Orbit (LEO) satellite communication systems. GEO satellites orbit at an altitude of 35,786 km, and their main advantage is that they remain relatively stationary compared to the ground and provide a large coverage area. However, GEO satellite communication also has significant disadvantages: the large distance between GEO satellites and Earth results in high free-space propagation loss, leading to tight communication link budgets; and large-aperture antennas are required to increase transmission or reception gain. GEO communication also suffers from high transmission latency, reaching approximately 500 ms round-trip time, which cannot meet the demands of low-latency services. Furthermore, GEO orbital resources are relatively scarce, resulting in high launch costs and an inability to provide coverage to the polar regions. MEO satellites orbit at altitudes between 2000 and 35786 km. Their advantage lies in achieving global coverage with a relatively small number of satellites. However, their orbital altitude is higher than LEO satellites, resulting in significantly longer communication transmission latency. LEO satellites, on the other hand, orbit at altitudes between 300 and 2000 km. LEO satellites are lower than MEO and GEO satellites, offering advantages such as lower data transmission latency, less transmission loss, and lower launch costs. Of course, in specific application scenarios, LEO satellites can be replaced by GEO or MEO satellites, or even a combination of multiple satellite types.

[0036] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0037] Please see Figure 2 This application provides an uplink synchronization method, including: Step S110: After completing the initial downlink synchronization, periodically receive synchronization signal blocks and measure the downlink time offset measurement value corresponding to each synchronization signal block. The aforementioned Synchronization Signal Block (SSB) is a key signal structure in wireless communication systems (such as 5G NR and satellite communication) used for initial access, time synchronization, and frequency synchronization. It mainly consists of the Primary Synchronization Signal (PSS), the Secondary Synchronization Signal (SSS), and the Physical Broadcast Channel (PBCH). The PSS is primarily used for initial time and frequency synchronization of the terminal, helping it determine the signal's time slot structure and partial cell identity. The SSS, in conjunction with the PSS, is used for complete cell identification and frame synchronization, providing a more accurate time reference. The PBCH carries crucial system information (such as broadcast messages and cell configuration parameters), and the terminal needs to demodulate the PBCH to obtain basic communication parameters. Furthermore, the SSB is typically transmitted repeatedly at fixed intervals (e.g., 5ms, 10ms, 20ms, 40ms, 80ms, or 160ms in 5G NR) to ensure the terminal can access the network at any time.

[0038] The initial downlink synchronization described above is a crucial step for terminals to establish communication, and its main steps include: Step 1, blind SSB inspection, mainly includes: SSB Slot Scanning: After the terminal powers on, it scans for possible SSB locations according to the SSB period specified in the protocol (such as 5ms, 10ms, etc. in 5G NR) and slot structure. Since the terminal is unaware of the network's time and frequency information at this time, blind detection needs to be performed on multiple slots and frequencies.

[0039] Detecting the PSS: During the scanning process, the terminal first detects the PSS. The PSS has a clear time domain and frequency domain structure. The terminal identifies the characteristic waveforms of the PSS through matched filtering or correlation operations, thereby obtaining preliminary time synchronization information (such as time slot boundaries).

[0040] SSS Detection: After detecting PSS, the terminal further detects SSS based on the location of PSS. SSS carries cell identity information and some system parameters, helping the terminal determine the specific cell identity and frame structure.

[0041] Demodulating PBCH: After detecting PSS and SSS, the terminal uses the demodulation reference signal (DM-RS) to demodulate PBCH. PBCH contains critical system information, such as broadcast messages, cell configuration parameters, and system frame number (SFN).

[0042] Step 2: Perform initial downlink synchronization, which mainly includes: Time synchronization: By detecting the PSS and SSS, the terminal determines the position of the SSB in the time domain, thereby obtaining the downlink time reference. This includes information on slot boundaries and frame boundaries, enabling the terminal to correctly demodulate subsequent downlink signals.

[0043] Frequency synchronization: The terminal uses the frequency domain characteristics of PSS and SSS to calibrate the frequency of the local oscillator, eliminating the effects of Doppler frequency deviation and crystal frequency deviation, thereby achieving frequency synchronization.

[0044] Cell access: The terminal obtains the basic configuration and broadcast messages of the cell based on the demodulated PBCH information, and completes the initial access to the target cell.

[0045] Step 3: Perform time-off pre-compensation, which mainly includes: After initial downlink synchronization is achieved, the terminal periodically receives ephemeris information broadcast by the satellite. This ephemeris information includes parameters such as the satellite's position, velocity, and time. The terminal uses this information to predict Doppler time offset and performs pre-compensation to reduce the impact of the Doppler effect.

[0046] After time offset pre-compensation, the terminal can continue to measure the downlink time offset value of SSB in subsequent SSB cycles. The downlink time offset measurement value mainly includes Doppler residual time offset and crystal oscillator time offset.

[0047] It is understood that the above-mentioned initial downlink synchronization process is a well-known and mature technology in the field. For more specific implementation methods of initial downlink synchronization, please refer to the relevant technologies. The embodiments of this invention will not be described in detail here.

[0048] Step S120: Extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block.

[0049] Optionally, step S120 may include: determining the target synchronization signal block and a predetermined number of consecutive synchronization signal blocks preceding the target synchronization signal block, and determining multiple downlink time offset measurements; determining the crystal oscillator time offset variation rate of the crystal oscillator time offset component based on the multiple downlink time offset measurements; determining the crystal oscillator time offset component in the downlink time offset measurements corresponding to the target synchronization signal block based on the crystal oscillator time offset variation rate; and determining the Doppler residual time offset component based on the downlink time offset measurements of the target synchronization signal block and the crystal oscillator time offset component.

[0050] The aforementioned crystal oscillator time offset variation rate refers to the cumulative time offset of the crystal oscillator time offset per unit time. It can be understood that the crystal oscillator time offset is mainly caused by the frequency deviation of the crystal oscillator between the transmitter and receiver, and typically changes linearly with time. This allows the crystal oscillator time offset variation rate to reflect the long-term trend of the crystal oscillator time offset. Based on the crystal oscillator time offset variation rate, combined with the time position of the target synchronization signal block, the corresponding crystal oscillator time offset component can be calculated.

[0051] The above scheme is based on the characteristic that the crystal oscillator time offset changes linearly with time. By analyzing the downlink time offset measurements of the target synchronization signal block and several previous synchronization signal blocks, the crystal oscillator time offset change rate is determined. This allows for the accurate extraction of the crystal oscillator time offset component corresponding to the target synchronization signal block, making the separation of the crystal oscillator time offset and the Doppler residual time offset more precise, which is beneficial to improving the time synchronization accuracy of the above time synchronization method. On the other hand, based on the crystal oscillator time offset change rate and the total downlink time offset measurement of the target synchronization signal block, the Doppler residual time offset component corresponding to the target synchronization signal block can be accurately calculated, providing a precise basis for subsequent uplink compensation. Furthermore, by extracting the crystal oscillator time offset component and the Doppler residual component before sending the next synchronization signal block and performing uplink residual time offset compensation, the above uplink synchronization method can compensate for the uplink residual time offset in real time and efficiently, reducing synchronization delay and enhancing the stability and reliability of the communication system.

[0052] The above scheme can obtain the crystal oscillator time offset rate of change of the crystal oscillator time offset component through at least one or more of the following methods: The first implementation method: obtaining the value by taking the average; Optionally, the above-mentioned determination of the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on multiple downlink time offset measurements includes: averaging the multiple downlink time offset measurements to determine the crystal oscillator time offset rate of change of the crystal oscillator time offset component. An example of this implementation is:

[0053] in, The time-off component of the crystal oscillator represents the rate of change of the crystal oscillator's time-off The number of downlink time offset measurements used in calculating the crystal oscillator time offset variation rate; for The first of the downshift time deviation measurements Each downward offset measurement value is in seconds; The SSB period is measured in seconds.

[0054] Understandably, since the Doppler residual time offset is random and has zero mean, these random Doppler residual time offsets can cancel each other out in multiple downlink time offset measurements. Averaging can smooth out these short-term random fluctuations, making the long-term trend of the crystal oscillator time offset more apparent, thus allowing for a more accurate determination of the crystal oscillator time offset rate of change.

[0055] The above scheme is based on the zero-mean characteristic of Doppler residual time offset. By averaging multiple downlink time offset measurements, the influence of Doppler residual time offset on crystal oscillator time offset can be effectively reduced, enabling the above uplink synchronization method to stably and accurately determine the crystal oscillator time offset change rate, thereby improving the time synchronization accuracy of the above uplink synchronization method. On the other hand, the averaging operation is simple to implement, has low computational resource requirements, and can quickly obtain the crystal oscillator time offset change rate, which is beneficial to improving the real-time performance of the above uplink synchronization method.

[0056] The second implementation method: obtaining the result based on linear fitting; Optionally, the above method for determining the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on multiple downlink time offset measurements includes: performing linear fitting on multiple downlink time offset measurements to obtain a fitting relationship between multiple downlink time offset measurements and time; and determining the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on the slope in the fitting relationship.

[0057] It is understandable that the crystal oscillator time offset exhibits linear accumulation, while the Doppler residual time offset exhibits zero-mean random fluctuation. When the downlink time offset measurements of a set of continuous synchronization signal blocks are approximated by a straight line, the slope of the line is mainly determined by the linear component, since the random components (i.e., the Doppler residual components) statistically cancel each other out. The linear component in the downlink time offset measurements is the crystal oscillator time offset component; therefore, the slope of the line is the rate of change of the crystal oscillator time offset.

[0058] The above scheme, by linearly fitting multiple downlink time offset measurements, can clearly capture the trend of time offset change over time, thereby more accurately determining the crystal oscillator time offset change rate and avoiding interference from short-term fluctuations. On the other hand, the slope of the fitted relationship directly corresponds to the crystal oscillator time offset change rate. This calculation method based on a physical model not only improves the accuracy of determining the crystal oscillator time offset change rate but also enhances the interpretability of the results. Furthermore, linear fitting is a common mathematical tool that is easy to implement and computationally efficient, enabling it to run quickly on the terminal. This is beneficial for improving the timeliness and effectiveness of the above uplink synchronization method in compensating for uplink residual time offset.

[0059] The third implementation method: obtaining the data using Kalman filtering; The crystal oscillator time offset and its rate of change are dynamically estimated by using a state-space model. The crystal oscillator time offset rate of change is recursively estimated by combining a system model (such as a linear change model of the crystal oscillator time offset) and observation data (downlink time offset measurement).

[0060] The fourth implementation method: obtaining it using machine learning; Machine learning algorithms (such as linear regression, support vector regression, random forest regression, etc.) are used to model the time offset measurement and predict the crystal oscillator time offset rate.

[0061] The following describes the timing of acquiring the target synchronization signal block in the above scheme, that is, the triggering timing for uplink residual time offset compensation: The above scheme can trigger uplink residual time-bias compensation in at least two ways: The first method: trigger uplink residual time offset compensation once for each SSB received; Each time the terminal successfully receives and measures the downlink time offset of any SSB, it immediately treats that SSB as a "target synchronization signal block," and then extracts the crystal oscillator time offset component and the Doppler residual time offset component, and performs an uplink residual time offset compensation. This block-by-block compensation mode compresses the update interval to a single SSB period (such as 5ms, 10ms, etc.), which is suitable for high-speed mobile or rapidly changing channel scenarios, and can control the residual error to a minimum.

[0062] The second method: Trigger uplink residual time offset compensation according to the uplink compensation preset cycle; Optionally, the above uplink synchronization method further includes: acquiring the target signal synchronization block at each uplink compensation preset period.

[0063] The terminal internally sets a relatively long fixed period. Each time this period expires, the terminal selects one of the most recently received SSBs as the "target synchronization signal block" and performs a centralized uplink residual time offset compensation. This periodic compensation mode reduces computational and signaling overhead, making it more suitable for terminals with relatively stable channels or limited power consumption. Furthermore, it's understandable that in communication systems, the basic unit of time is the number of SSBs; therefore, the preset uplink compensation period can be represented by the number of SSBs, and its length can be an integer multiple of the SSB period. It's also important to note that since the crystal oscillator time offset rate of change is a slowly drifting straight line, while the Doppler residual time offset is noise that fluctuates rapidly around zero mean, only with a sufficiently long observation window can the positive and negative fluctuations of the noise statistically cancel each other out, allowing the crystal oscillator time offset rate of change to stand out from the noise. If the sample duration is too short, random fluctuations will not be averaged out, and the calculated crystal oscillator time offset rate of change will be contaminated by noise, leading to the misinterpretation of the Doppler residual time offset as the crystal oscillator time offset, thus introducing a systematic bias into the uplink compensation. Therefore, sufficient continuous data should be collected first to ensure that random components are adequately averaged, thus reliably extracting the true rate of change of the crystal oscillator time offset. Subsequent residual time offset compensation will then avoid amplifying errors. For example, after the terminal's initial startup or cold start, at least 10 seconds of continuous downlink time offset measurements can be collected before performing the first uplink residual time offset compensation. The initialization phase ensures sufficient samples for estimating the crystal oscillator time offset rate of change, avoiding amplification of early compensation errors. Subsequent compensation can operate normally using either a per-SSB trigger mechanism or a preset uplink compensation period.

[0064] The above scheme acquires the target signal synchronization block at preset uplink compensation intervals to periodically compensate for the uplink residual time offset. Each compensation can closely reflect the actual communication situation at the most recent time, which is beneficial to improving the time synchronization accuracy of the uplink synchronization. On the one hand, this method of periodically acquiring the target signal synchronization block helps to promptly detect and adapt to changes in the communication environment, which is beneficial to improving the adaptability and reliability of the uplink synchronization method. On the other hand, by setting an appropriate preset period, a balance can be achieved between compensation accuracy and system resource consumption, so as to achieve timely compensation without increasing unnecessary resource overhead due to excessively frequent acquisition of synchronization blocks.

[0065] Optionally, the above-mentioned determination of the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate includes: determining the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate and the uplink compensation preset period. An example of this implementation is: The number of SSBs corresponding to the preset uplink compensation period is: At the time of the first time, for the second time The SSB and the first Downward time-biased cumulative value between individual SSBs The time-off component of the crystal oscillator and Doppler residual partial component The calculation is as follows:

[0066]

[0067] in, This is the off-axis component when the crystal oscillator is in operation; This represents the rate of change of the crystal oscillator's time-displacement. For SSB cycles; This represents the interval between two uplink residual offset compensations. This represents the cumulative crystal oscillator time offset between the last uplink residual time offset compensation and the current uplink residual time offset compensation, i.e. The time-off component of the crystal oscillator; This represents the cumulative downlink time offset between two uplink residual time offset compensations; This refers to the partial component of the Doppler residual; it is understandable that in a mechanism employing per-SSB triggered compensation, .

[0068] In addition, it should be noted that when performing the first uplink residual time offset compensation, the above-mentioned crystal oscillator time offset component should also be calculated based on the number of selected samples. The calculation of the crystal oscillator time offset component should also be aimed at calculating the cumulative amount of crystal oscillator time offset from the time of the last uplink residual time offset compensation to the time of this uplink residual time offset compensation.

[0069] The above scheme determines the crystal oscillator time offset component by combining the crystal oscillator time offset change rate with the uplink compensation preset period. This can more accurately match the actual needs of uplink compensation. This not only takes into account the long-term drift characteristics of the crystal oscillator, but also matches the periodicity of uplink compensation, which is conducive to improving the time synchronization accuracy of the above uplink synchronization method. On the other hand, adjusting the calculation of the crystal oscillator time offset component according to the preset period can ensure that the compensation action matches the timing requirements of the communication system, thereby improving communication efficiency. Furthermore, determining the crystal oscillator time offset component in conjunction with the preset period helps to maintain the consistency and stability of compensation under different environmental conditions, thereby improving the reliability of the compensation effect.

[0070] Step S130: Before sending the uplink signal, perform uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component.

[0071] Optionally, the above step S130, which compensates for the uplink residual time offset based on the crystal oscillator time offset component, can be implemented by: compensating for the uplink residual time offset of the crystal oscillator time offset component in the same direction as the time offset direction of the crystal oscillator time offset component. For example, in the first... When performing uplink residual time offset compensation at each SSB time, the uplink crystal oscillator time offset is calculated according to... Compensation will be made for the residual upward Doppler readings. Compensation will be provided.

[0072] Crystal oscillator time offset is caused by the frequency deviation of the crystal oscillator at the transmitting and receiving ends, manifesting as clock drift that accumulates linearly over time. For example, if the terminal's crystal oscillator frequency is slightly lower than the satellite crystal oscillator frequency, the terminal's local clock will gradually lag behind the satellite clock. Because crystal oscillator time offset has the same impact on uplink and downlink, uplink compensation needs to be performed in the same direction as the downlink measurement. If the downlink measurement shows a crystal oscillator time offset of... If the terminal lags, then the terminal needs to postpone the transmission time during uplink transmission. This ensures that the uplink signal arrives at the satellite at the expected time.

[0073] The above scheme can accurately correct the accumulated error caused by the crystal oscillator by compensating the crystal oscillator time offset component according to its time offset direction, and achieve accurate alignment of uplink transmission time, effectively reducing the risk of loss of synchronization caused by error superposition. On the other hand, by specifically compensating the crystal oscillator time offset component, the uplink can be made more stable, which is conducive to improving the synchronization effect of the above uplink synchronization method.

[0074] Optionally, the above step S130 can be performed by compensating for the upward residual time offset based on the Doppler residual time offset component as follows: based on the Doppler residual time offset component, perform upward residual time offset compensation on the Doppler residual time offset component in a direction opposite to the time offset direction of the Doppler residual time offset component.

[0075] Doppler residual time offset originates from the relative motion between the satellite and the terminal, causing changes in signal path delay during transmission. For example, if the satellite moves away from the terminal, the signal propagation delay increases, resulting in downlink signal reception lag. The Doppler time offset has opposite effects on the uplink and downlink. In the downlink, a positive Doppler time offset (lag) measured by the terminal means the signal arrives later than expected. However, in the uplink, to compensate for the path change, the terminal needs to send the signal earlier; therefore, the compensation direction is opposite to the Doppler time offset direction. If the Doppler residual time offset is... (Lag) In this case, the uplink needs to send the data earlier. This ensures the signal arrives at the satellite on time. For example, if the satellite is closer to the terminal, the signal propagation path is shorter, the propagation delay is reduced, and the downlink reception signal is received earlier. The Doppler time offset has opposite effects on the uplink and downlink. In the downlink, a negative Doppler time offset (earlier arrival) measured by the terminal means the signal arrives earlier than expected; however, in the uplink, to compensate for the path change, the terminal needs to delay transmitting the signal, so the compensation direction is opposite to the Doppler time offset direction. If the residual Doppler time offset is... (If sent earlier), the uplink transmission needs to be delayed. This ensures that the signal reaches the satellite on time.

[0076] The above scheme can effectively offset the time offset caused by the relative motion of the satellite by compensating for the Doppler residual time offset component in the opposite direction, so that the uplink signal can adapt to the path change in advance or delay, which is beneficial to improving the adaptability of the above uplink synchronization method. On the other hand, by specifically compensating for the Doppler residual time offset component, the uplink can be made more stable, which is beneficial to improving the synchronization effect of the above uplink synchronization method.

[0077] Please see Figure 3 Based on the same inventive concept, this application also provides an uplink synchronization device 200, comprising: The downlink time offset measurement acquisition module 210 is used to periodically receive synchronization signal blocks and measure the downlink time offset measurement value corresponding to each synchronization signal block after the initial downlink synchronization is completed. The component extraction module 220 is used to extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block; The uplink compensation module 230 is used to perform uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component before sending the uplink signal.

[0078] Optionally, the component extraction module 220 is specifically used for: determining a target synchronization signal block and a plurality of downlink time offset measurements corresponding to a preset number of consecutive synchronization signal blocks preceding the target synchronization signal block; determining the crystal oscillator time offset variation rate of the crystal oscillator time offset component based on the plurality of downlink time offset measurements; determining the crystal oscillator time offset component in the downlink time offset measurements corresponding to the target synchronization signal block based on the crystal oscillator time offset variation rate; and determining the Doppler residual time offset component based on the downlink time offset measurements of the target synchronization signal block and the crystal oscillator time offset component.

[0079] Optionally, the component extraction module 220 is specifically used to: average multiple downlink time offset measurements to determine the crystal oscillator time offset rate of change of the crystal oscillator time offset component.

[0080] Optionally, the component extraction module 220 is specifically used to: perform linear fitting on multiple downlink time offset measurements to obtain a fitting relationship between the multiple downlink time offset measurements and time; and determine the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on the slope in the fitting relationship.

[0081] Optionally, the component extraction module 220 is specifically used to: obtain the target signal synchronization block at each uplink compensation preset period.

[0082] Optionally, the component extraction module 220 is specifically used to: determine the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate and the uplink compensation preset period.

[0083] Optionally, the aforementioned uplink compensation module 230 is specifically used for: performing uplink residual time offset compensation on the crystal oscillator time offset component in the same direction as the time offset direction of the crystal oscillator time offset component based on the crystal oscillator time offset component; and performing uplink residual time offset compensation on the Doppler residual time offset component in the opposite direction to the time offset direction of the Doppler residual time offset component based on the Doppler residual time offset component.

[0084] Based on the same inventive concept, this application also provides a ground terminal, including a baseband processor, wherein: The baseband processor is configured to periodically receive synchronization signal blocks and measure the downlink time offset measurement value corresponding to each synchronization signal block after initial downlink synchronization is completed; extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block; and perform uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component before transmitting the uplink signal.

[0085] Figure 4This is a schematic diagram of an electronic device provided in an embodiment of this application. (Refer to...) Figure 4 The electronic device 300 includes a processor 310, a memory 320, and a communication interface 330. These components are interconnected and communicate with each other via a communication bus 340 and / or other forms of connection mechanism (not shown).

[0086] The memory 320 includes one or more (only one is shown in the figure), which may be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc. The processor 310 and other possible components may access the memory 320 to read and / or write data therein.

[0087] Processor 310 includes one or more (only one is shown in the figure), which can be an integrated circuit chip with signal processing capabilities. The processor 310 described above can be a general-purpose processor, including a central processing unit (CPU), a microcontroller unit (MCU), a network processor (NP), or other conventional processors; it can also be a special-purpose processor, including a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0088] Communication interface 330 includes one or more (only one is shown in the figure) that can be used to communicate directly or indirectly with other devices to exchange data. For example, communication interface 330 can be an Ethernet interface; it can be a mobile communication network interface, such as an interface for 3G, 4G, or 5G networks; or it can be other types of interfaces with data transmission and reception capabilities.

[0089] One or more computer program instructions may be stored in the memory 320, and the processor 310 may read and run these computer program instructions to implement the uplink synchronization method provided in the embodiments of this application and other desired functions.

[0090] Understandable. Figure 4 The structure shown is for illustrative purposes only; the electronic device 300 may also include components that are more advanced than those shown. Figure 4 The more or fewer components shown, or having the same Figure 4 The different configurations shown. Figure 4 The components shown can be implemented using hardware, software, or a combination thereof. For example, electronic device 300 can be a single server (or other device with computing power), a combination of multiple servers, a cluster of a large number of servers, etc., and can be either a physical device or a virtual device.

[0091] As one implementation method, the aforementioned electronic device 300 can be a terminal, and different terminals can be interconnected via wired or wireless means. Terminals can be widely used in various scenarios, such as Near Field Communication (NFC) device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities.

[0092] The terminal may also be referred to as a mobile station (MS), terminal, or terminal equipment, and may include a subscriber unit, cellular phone, smartphone, wireless data card, personal digital assistant (PDA) computer, tablet computer, wireless modem, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, machine type communication (MTC) terminal, etc. For ease of description, all devices mentioned above are referred to as terminals in all embodiments of this application.

[0093] The aforementioned terminal may further include an antenna and a transceiver. The transceiver modulates (e.g., analog-to-digital conversion, filtering, amplification, and up-conversion) the output sample and generates an uplink signal, which is transmitted to the network device via the antenna. On the downlink, the antenna receives the downlink signal transmitted by the network device, and the transceiver modulates (e.g., filtering, amplification, down-conversion, and digitization) the signal received from the antenna and provides input sampling. The processor 310 is used to execute the uplink synchronization method described in the above embodiments. The embodiments of this application do not limit the specific technology or device form used in the terminal.

[0094] This application also provides a computer-readable storage medium storing computer program instructions. These computer program instructions are read and executed by a computer's processor to perform the uplink synchronization method provided in this application. For example, the computer-readable storage medium can be implemented as follows: Figure 4 The memory 320 in the electronic device 300.

[0095] This application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the uplink synchronization method provided in this application.

[0096] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0097] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0098] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0099] It should be noted that if the function is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0100] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0101] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0102] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0103] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0104] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0105] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An uplink synchronization method, characterized in that, The method includes: After initial downlink synchronization is completed, synchronization signal blocks are periodically received and downlink time offset measurements are taken for each synchronization signal block. Extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block; Before sending the uplink signal, uplink residual time offset compensation is performed based on the crystal oscillator time offset component and the Doppler residual time offset component; Extracting the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block includes: determining the target synchronization signal block and a predetermined number of consecutive synchronization signal blocks preceding the target synchronization signal block, corresponding to multiple downlink time offset measurement values; determining the crystal oscillator time offset change rate of the crystal oscillator time offset component based on the multiple downlink time offset measurement values; determining the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate; and determining the Doppler residual time offset component based on the downlink time offset measurement value and the crystal oscillator time offset component of the target synchronization signal block. The method for compensating for the residual time offset based on the crystal oscillator time offset component is as follows: based on the crystal oscillator time offset component, perform uplink residual time offset compensation on the crystal oscillator time offset component in the same direction as the time offset direction of the crystal oscillator time offset component; The method for uplink residual time offset compensation based on the Doppler residual time offset component is as follows: based on the Doppler residual time offset component, the uplink residual time offset compensation is performed on the Doppler residual time offset component in a direction opposite to the time offset direction of the Doppler residual time offset component.

2. The uplink synchronization method according to claim 1, characterized in that, The step of determining the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on multiple downlink time offset measurements includes: The average value of the multiple downlink time offset measurements is taken to determine the crystal oscillator time offset rate of change of the crystal oscillator time offset component.

3. The uplink synchronization method according to claim 1, characterized in that, The step of determining the crystal oscillator time offset rate of change of the crystal oscillator time offset component based on multiple downlink time offset measurements includes: Linear fitting is performed on multiple downlink time offset measurements to obtain the fitting relationship between the multiple downlink time offset measurements and time. Based on the slope in the fitted relationship, the crystal oscillator time deviation rate of the crystal oscillator time deviation component is determined.

4. The uplink synchronization method according to claim 1, characterized in that, The method further includes: The target signal synchronization block is obtained at each uplink compensation preset period.

5. The uplink synchronization method according to claim 4, characterized in that, The step of determining the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate includes: Based on the crystal oscillator time offset change rate and the uplink compensation preset period, the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block is determined.

6. An uplink synchronization device, characterized in that, include: The downlink time offset measurement acquisition module is used to periodically receive synchronization signal blocks and measure the downlink time offset measurement value corresponding to each synchronization signal block after the initial downlink synchronization is completed. The component extraction module is used to extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block; An uplink compensation module is used to perform uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component before sending the uplink signal; The component extraction module is specifically used to: determine the target synchronization signal block and a preset number of consecutive synchronization signal blocks preceding the target synchronization signal block, and the multiple downlink time offset measurements corresponding to them; and determine the crystal oscillator time offset variation rate of the crystal oscillator time offset component based on the multiple downlink time offset measurements. Based on the crystal oscillator time offset change rate, determine the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block; Based on the downlink time offset measurement value of the target synchronization signal block and the crystal oscillator time offset component, the Doppler residual time offset component is determined; The uplink compensation module is specifically used to: perform uplink residual time offset compensation on the crystal oscillator time offset component based on the crystal oscillator time offset component, in the same direction as the time offset direction of the crystal oscillator time offset component; The uplink compensation module is specifically used to: perform uplink residual time offset compensation on the Doppler residual time offset component in a direction opposite to the time offset direction of the Doppler residual time offset component, based on the Doppler residual time offset component.

7. A ground terminal, characterized in that, Including the baseband processor, where: The baseband processor is configured to periodically receive synchronization signal blocks and measure the downlink time offset measurement value corresponding to each synchronization signal block after completing the initial downlink synchronization; extract the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block; and perform uplink residual time offset compensation based on the crystal oscillator time offset component and the Doppler residual time offset component before transmitting the uplink signal. Extracting the crystal oscillator time offset component and the Doppler residual time offset component from the downlink time offset measurement value corresponding to the target synchronization signal block includes: determining the target synchronization signal block and a predetermined number of consecutive synchronization signal blocks preceding the target synchronization signal block, corresponding to multiple downlink time offset measurement values; determining the crystal oscillator time offset change rate of the crystal oscillator time offset component based on the multiple downlink time offset measurement values; determining the crystal oscillator time offset component in the downlink time offset measurement value corresponding to the target synchronization signal block based on the crystal oscillator time offset change rate; and determining the Doppler residual time offset component based on the downlink time offset measurement value and the crystal oscillator time offset component of the target synchronization signal block. The method for compensating for the residual time offset based on the crystal oscillator time offset component is as follows: based on the crystal oscillator time offset component, perform uplink residual time offset compensation on the crystal oscillator time offset component in the same direction as the time offset direction of the crystal oscillator time offset component; The method for uplink residual time offset compensation based on the Doppler residual time offset component is as follows: based on the Doppler residual time offset component, the uplink residual time offset compensation is performed on the Doppler residual time offset component in a direction opposite to the time offset direction of the Doppler residual time offset component.

8. An electronic device, characterized in that, include: A processor, a memory, and a communication bus, wherein the processor and the memory communicate with each other via the communication bus; The memory stores program instructions that can be executed by the processor, and the processor can execute the method as described in any one of claims 1 to 5 by calling the program instructions.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, which, when executed by a computer, cause the computer to perform the method as described in any one of claims 1 to 5.

10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 5.

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