Doppler frequency shift compensation method and device and electronic equipment

Abstract

The invention discloses a Doppler frequency shift compensation method, a Doppler frequency shift compensation device and electronic equipment. The method comprises: a user equipment receiving a first message issued by a satellite, the first message carrying a first compensation value corresponding to a Doppler frequency shift between the satellite and the user equipment, and the first compensation value being used for pre-compensating a downlink signal sent by the satellite; in response to the first message, determining the distance between the user equipment and the beam center position of the satellite; and under the condition that the distance is greater than a preset threshold value, performing post-compensation on the frequency deviation of the received downlink signal according to the first compensation value. According to the invention, the technical problem that the accuracy of satellite compensation and the power consumption of terminal compensation cannot be effectively balanced in a Doppler frequency offset compensation scheme adopted by the related technology by adopting a sending end compensation or receiving end compensation mode is solved.

Description

Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a Doppler frequency shift compensation method, apparatus, and electronic device. Background Technology

[0002] Doppler shift is a physical phenomenon that describes the frequency change caused by the relative motion between a wave source and a receiver. In satellite communications, this manifests as a frequency shift in the signal frequency due to the relative velocity between the satellite and the ground user equipment (UE) during communication. In non-geostationary orbit (NEO) satellite communication systems, both the service link and the feed link are affected by Doppler shift due to the high-speed motion of the satellite relative to the Earth's surface.

[0003] However, the Doppler frequency offset compensation schemes used in related technologies, such as the service link and the feeder link, adopt different compensation strategies. By choosing between compensation at the transmitting end or compensation at the receiving end, it is impossible to effectively balance the accuracy of satellite compensation and the power consumption of terminal compensation.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This application provides a Doppler frequency shift compensation method, apparatus, and electronic device to at least solve the technical problem that the Doppler frequency shift compensation schemes used in related technologies cannot effectively balance the accuracy of satellite compensation and the power consumption of terminal compensation by using transmitter-end compensation or receiver-end compensation.

[0006] According to one aspect of the embodiments of this application, a Doppler frequency shift compensation method is provided, comprising: a user equipment receiving a first message transmitted by a satellite, wherein the first message carries a first compensation value corresponding to the Doppler frequency shift between the satellite and the user equipment, the first compensation value being used to pre-compensate the downlink signal transmitted by the satellite; in response to the first message, determining the distance between the user equipment and the beam center position of the satellite; and, if the distance is greater than a preset threshold, performing post-compensation on the frequency offset of the received downlink signal based on the first compensation value.

[0007] In some embodiments of this application, it is further included that: if the distance is less than or equal to a preset threshold, post-compensation is no longer performed.

[0008] In some embodiments of this application, when the distance is greater than a preset threshold, post-compensation is performed on the frequency offset of the received downlink signal based on a first compensation value, including: determining a second compensation value corresponding to the Doppler frequency shift between the satellite and the satellite; and post-compensating the frequency offset of the downlink signal based on the first compensation value and the second compensation value.

[0009] In some embodiments of this application, post-compensation is performed on the frequency offset of the downlink signal based on a first compensation value and a second compensation value, including: determining the difference between the first compensation value and the second compensation value; and adjusting the frequency offset of the downlink signal using the difference.

[0010] In some embodiments of this application, before determining the distance between the user equipment and the beam center position of the satellite in response to the first message, the method further includes: receiving a second ephemeris broadcast message sent by the satellite, wherein the second ephemeris broadcast message is used to carry the beam center position and ephemeris information of the satellite.

[0011] In some embodiments of this application, determining a second compensation value corresponding to the Doppler shift with the satellite includes: obtaining ephemeris information from a second ephemeris broadcast message; and determining the second compensation value based on the ephemeris information.

[0012] In some embodiments of this application, the first message includes a first ephemeris broadcast message carrying ephemeris information sent by a satellite.

[0013] According to another aspect of the embodiments of this application, another Doppler frequency shift compensation method is also provided, including: a satellite determining a first compensation value corresponding to the Doppler frequency shift between itself and multiple user equipments within the beam coverage area, wherein the first compensation value is used to pre-compensate the downlink signal transmitted to the user equipment; and sending a first message carrying the first compensation value to the user equipment, wherein the first message is used to instruct the first user equipment to use the first compensation value to post-compensate the frequency offset of the received downlink signal, the first user equipment including user equipment among multiple user equipments whose distance from the beam center position of the satellite is greater than a preset threshold.

[0014] In some embodiments of this application, the first message includes a first ephemeris broadcast message carrying ephemeris information.

[0015] In some embodiments of this application, the method further includes: sending a second ephemeris broadcast message carrying the beam center position to the user equipment, wherein the second ephemeris broadcast message is used to instruct the user equipment to determine the distance from the beam center position.

[0016] According to another aspect of the embodiments of this application, a Doppler frequency shift compensation device is also provided, comprising: a receiving module, configured to receive a first message transmitted by a satellite, wherein the first message carries a first compensation value corresponding to the Doppler frequency shift between the satellite and the user equipment, the first compensation value being used to pre-compensate the downlink signal transmitted by the satellite; a first determining module, configured to determine the distance between the user equipment and the beam center position of the satellite in response to the first message; and a compensation module, configured to perform post-compensation on the frequency offset of the received downlink signal based on the first compensation value when the distance is greater than a preset threshold.

[0017] According to another aspect of the embodiments of this application, another Doppler frequency shift compensation device is also provided, comprising: a second determining module, configured to determine a first compensation value corresponding to the Doppler frequency shift between a satellite and multiple user equipments within the beam coverage area, wherein the first compensation value is used to pre-compensate the downlink signal transmitted to the user equipment; and a transmitting module, configured to transmit a first message carrying the first compensation value to the user equipment, wherein the first message is used to instruct a first user equipment to use the first compensation value to post-compensate the frequency offset of the received downlink signal, the first user equipment including user equipment among multiple user equipments whose distance from the beam center position of the satellite is greater than a preset threshold.

[0018] According to another aspect of the embodiments of this application, an electronic device is also provided, including: a memory and a processor, wherein the memory is used to store program instructions; the processor is connected to the memory and is used to execute the above-described Doppler frequency shift compensation method.

[0019] According to another aspect of the embodiments of this application, a non-volatile storage medium is also provided, the non-volatile storage medium including a stored computer program, wherein the device on which the non-volatile storage medium is located executes the above-mentioned Doppler frequency shift compensation method by running the computer program.

[0020] According to another aspect of the embodiments of this application, a computer program product is also provided, including computer instructions that, when executed by a processor, implement the above-described Doppler frequency shift compensation method.

[0021] In this embodiment, a hybrid compensation method is adopted. Through the collaborative action of the satellite and the user equipment (UE), the global view of the satellite and the local precise location information of the UE are utilized to dynamically adjust the compensation mechanism, thereby improving the communication quality. This achieves the technical effects of reducing terminal power consumption and improving signal stability. In turn, it solves the technical problem in the Doppler frequency offset compensation schemes used in related technologies, which cannot effectively balance the accuracy of satellite compensation and the power consumption of terminal compensation by using the transmitting end compensation or the receiving end compensation method. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a hardware structure block diagram of a computer terminal for a Doppler frequency shift compensation method according to an embodiment of this application; Figure 2 This is a flowchart of a Doppler frequency shift compensation method according to an embodiment of this application; Figure 3This is a flowchart of another Doppler frequency shift compensation method according to an embodiment of this application; Figure 4 This is a schematic diagram of satellite beam coverage for a Doppler shift compensation method according to an embodiment of this application; Figure 5 This is a schematic diagram of the structure of a Doppler frequency shift compensation device according to an embodiment of this application; Figure 6 This is a schematic diagram of another Doppler frequency shift compensation device according to an embodiment of this application. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] To better understand the embodiments of this application, the technical terms involved in the embodiments of this application are explained below: Doppler shift: This refers to the change in phase and frequency caused by the difference in propagation path when a mobile station moves at a constant speed in a certain direction. It reveals how the properties of a wave change during motion. When the motion is in front of the wave source, the wave is compressed, the wavelength becomes shorter, and the frequency becomes higher (blue shift); when the motion is behind the wave source, the opposite effect occurs, the wavelength becomes longer, and the frequency becomes lower (red shift).

[0026] It should be noted that the frequency relationship between the receiver and the transmitter is as follows:

[0027] in, For the received frequency, The emission originates from the original emission frequency in this medium. Let be the speed at which the wave propagates in the medium. This represents the speed at which the receiver moves relative to the medium along the direction of the transmitter. If it is close to the transmitter, the forward operator is +; otherwise, it is -. This represents the speed at which the transmitter moves relative to the medium along the direction of the receiver. If the transmitter is close to the receiver, the preceding symbol is -; otherwise, it is +.

[0028] In satellite communication systems, especially in non-geostationary orbit satellite communication systems such as low Earth orbit and medium Earth orbit, satellites move at high speeds relative to the Earth's surface and sometimes approach and sometimes move away from fixed positions on the Earth's surface. Therefore, Doppler frequency shift exists when low Earth orbit satellites communicate with gateway stations and mobile terminals on the Earth's surface.

[0029] Service Link: In a satellite communication system, this refers to the communication link between the satellite and the UE, carrying downlink signals (from satellite to UE) and uplink signals (from UE to satellite). In this application embodiment, the service link is the main application scenario for the Doppler frequency offset (i.e., Doppler frequency shift) hybrid compensation method. By optimizing the downlink signal compensation mechanism of the service link, the quality of signals received by the terminal at different locations can be improved. In particular, for UEs at the beam edge, the combination of receiver-side post-compensation and satellite-side pre-compensation improves the accuracy of compensation.

[0030] Feeder Link: In a satellite communication system, this refers to the communication link between a ground gateway station and a satellite used to upload data and commands to the satellite or download data from the satellite to the ground gateway station. In this application embodiment, although the main focus is on the service link, the hybrid compensation strategy mentioned also applies to the feeder link, especially considering the Doppler frequency offset compensation of the satellite relative to the ground gateway station.

[0031] Hybrid Compensation is a Doppler frequency offset compensation strategy that combines pre-compensation at the transmitter and post-compensation at the receiver. In this embodiment, the hybrid compensation method introduces a dynamic switching mechanism based on the relative position of the UE and the satellite beam center for the first time. That is, the satellite sends the pre-compensation value and informs the UE of the beam center position. The UE decides whether to perform additional receiver compensation based on its own position. This method not only improves the accuracy and reliability of compensation, but also effectively balances the efficiency of satellite pre-compensation with the energy consumption of UE post-compensation.

[0032] Beam Center Position: The beam center position refers to the geometric center point of the satellite communication beam coverage area. In this embodiment, it is an important reference point for determining whether the UE needs to perform post-receiver compensation. The satellite sends the beam center position information to the UE through a broadcast message, allowing the UE to adjust the compensation strategy according to its distance from the beam center, thereby optimizing the performance of the overall communication network.

[0033] Ephemeris Information: Ephemeris information is a set of data describing the orbital parameters and position information of a satellite, including the satellite's instantaneous position, velocity, and future trajectory prediction. In the embodiments of this application, ephemeris information is the basic data for the UE and the satellite to calculate the Doppler frequency offset. By broadcasting ephemeris information, the UE can calculate the relative motion state with the satellite in real time, thereby accurately estimating the Doppler frequency offset and providing the necessary input information for the hybrid compensation strategy.

[0034] Transmitter compensation in Doppler frequency offset compensation refers to pre-compensating the signal before transmission based on the expected Doppler frequency offset, in order to reduce the frequency shift at the receiver caused by the Doppler effect. Both the terminal and the satellite can perform transmitter compensation.

[0035] (1) Terminal transmitter compensation: The UE calculates the Doppler frequency offset between itself and the satellite based on its own position, speed and satellite ephemeris information, and performs pre-compensation before transmitting the signal; (2) Satellite transmitter compensation: The satellite predicts the Doppler frequency offset between itself and the UE based on its orbital parameters and the UE's position information, and performs pre-compensation before transmitting the signal to the UE.

[0036] In Doppler frequency offset compensation, receiver compensation refers to compensating for the frequency offset caused by the Doppler effect at the signal receiving end. Both the terminal and the satellite can perform transmitter compensation.

[0037] (1) Terminal receiver compensation: The UE calculates the Doppler frequency offset between itself and the satellite based on its own position, speed and satellite ephemeris information, and performs compensation when receiving signals; (2) Satellite receiver compensation: The satellite performs Doppler frequency offset compensation when receiving signals sent by the UE. This requires the satellite to have the corresponding processing capability to estimate the Doppler frequency offset caused by the movement of the UE and make corresponding adjustments when receiving signals.

[0038] In 3GPP Rel-17 NTN, since the scenario is set as transparent satellite relay, the impact of Doppler frequency shift includes both the serving link and the feeder link. One hybrid compensation method is that on the serving link, the UE calculates and compensates for the Doppler frequency shift based on its own location information and ephemeris information. On the feeder link, since the location information of the ground gateway station is sometimes lacking, the satellite side calculates and compensates for the Doppler frequency shift.

[0039] However, the hybrid Doppler frequency offset compensation in related technologies refers to using different compensation methods for the serving link and the feeder link. The serving link has two methods: transmitter-side compensation and receiver-side compensation. These two methods are mutually exclusive, and either can be used for both uplink and downlink signals. For downlink signals, in the satellite transmitter-side compensation scheme, the terminal does not perform compensation. The satellite calculates the relative velocity with the current beam center position based on its current motion state, and then calculates the Doppler frequency offset value. This value is most accurate at the beam center. As the terminal moves away from the beam center, the accuracy of this value decreases. Terminals located at the beam edge experience the largest Doppler frequency offset after compensation. In the terminal receiver-side compensation scheme, the satellite does not perform compensation, requiring all terminals within the beam coverage to perform compensation. Terminal compensation consumes terminal computing power, representing an additional overhead for the terminal.

[0040] To address the aforementioned technical problems, this application provides corresponding solutions, which are detailed below.

[0041] The Doppler shift compensation method provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Figure 1 A hardware block diagram of a computer terminal for implementing a Doppler frequency shift compensation method is shown. Figure 1 As shown, the computer terminal 10 may include one or more processors (shown as 102a, 102b, ..., 102n in the figure) (the processor may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.), a memory 104 for storing data, and a transmission module 106 for communication functions connected via wired and / or wireless networks. In addition, it may also include: a display, a keyboard, a cursor control device, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, and a BUS bus. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the aforementioned electronic device. For example, computer terminal 10 may also include... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0042] It should be noted that the aforementioned one or more processors and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuits may be a single, independent processing module, or may be integrated, in whole or in part, into any other element within the computer terminal 10. As involved in the embodiments of this application, the data processing circuits serve as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0043] The memory 104 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the Doppler shift compensation method in this embodiment. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory 104, thereby implementing the aforementioned Doppler shift compensation method. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor, and these remote memories can be connected to the computer terminal 10 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0044] The transmission module 106 is used to receive or send data via a network. Specific examples of the network described above may include a wireless network provided by the communication provider of the computer terminal 10. In one example, the transmission module 106 includes a network interface controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission module 106 may be a radio frequency (RF) module, used for wireless communication with the Internet.

[0045] The display can be, for example, a touchscreen liquid crystal display (LCD) that allows the user to interact with the user interface of the computer terminal 10.

[0046] It should be noted here that, in some optional embodiments, the above... Figure 1 The computer terminal shown may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium), or a combination of both hardware and software elements. It should be noted that... Figure 1 This is only one instance of a specific particular instance, and is intended to illustrate the types of components that may exist in the aforementioned computer terminal.

[0047] In the above operating environment, this application provides an embodiment of a Doppler frequency shift compensation method. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than that shown here.

[0048] Figure 2 This is a flowchart of a Doppler frequency shift compensation method according to an embodiment of this application, as shown below. Figure 2 As shown, the method includes the following steps: In step S202, the user equipment receives a first message sent by the satellite, wherein the first message carries a first compensation value corresponding to the Doppler frequency shift between the satellite and the user equipment, and the first compensation value is used to pre-compensate the downlink signal sent by the satellite.

[0049] In step S202 above, the first message is other types of broadcast messages or special signaling used in the satellite communication system to transmit various control information and parameters. The first compensation value is a value calculated by the satellite based on its own orbital parameters and the position of the beam coverage center, used to pre-compensate the downlink signal Doppler frequency offset. The first compensation value is most accurate for UEs at the beam center position, but the accuracy is reduced for UEs at the beam edge.

[0050] In some embodiments of this application, the first message includes a first ephemeris broadcast message sent by the satellite carrying ephemeris information, wherein the ephemeris information can be used by the UE to calculate its relative position and velocity with the satellite.

[0051] In addition to the first ephemeris broadcast message carrying ephemeris information, the first message can also be: (1) Broadcast control messages: Broadcast control messages in satellite communication systems may include Doppler frequency offset compensation values, beam center position information and other control parameters. Broadcast control messages are broadcast periodically to ensure that the UE can obtain the latest compensation parameters in a timely manner.

[0052] (2) System Information Message: In a satellite communication system, a system information message is used to broadcast system-level information to the UE, including network configuration, access parameters, etc. In some embodiments of this application, the system information message can be extended or customized to include Doppler frequency offset compensation values ​​and beam center location information so that the UE can perform accurate frequency compensation.

[0053] (3) Dedicated signaling messages: Unlike broadcast messages, dedicated signaling messages are dedicated control information sent by the satellite to a specific UE. When the UE accesses the system for the first time or when its location changes significantly, the satellite can send updated Doppler frequency offset compensation values ​​and beam center location information directly to the UE through dedicated signaling messages to provide a more personalized compensation strategy.

[0054] (4) Fast information broadcast: This is a broadcast mechanism that quickly updates key information. It aims to reduce the waiting time and power consumption of the UE when obtaining system information. Fast information broadcast can be specially designed to transmit dynamic information such as Doppler frequency offset compensation value and beam center position, so as to ensure that the UE can adjust the receiving frequency in time even in fast-moving scenarios.

[0055] (5) Enhanced broadcast messages: Enhanced broadcast messages are based on existing broadcast messages and can include more detailed and accurate satellite status information, such as instantaneous position, velocity, acceleration, etc., as well as Doppler frequency offset compensation values ​​calculated based on this information. The UE can use the information in the enhanced broadcast messages to perform more refined receiver compensation and improve signal reception quality.

[0056] In some embodiments of this application, the satellite sends a Doppler frequency offset pre-compensation value calculated based on the beam center position to the UE via a first message. Before transmitting the signal, the satellite pre-compensates the downlink signal based on this value.

[0057] Step S204: In response to the first message, determine the distance between the user equipment and the beam center position of the satellite.

[0058] In step S204 above, distance refers to the straight-line distance between the user equipment and the center point of the current satellite beam coverage area. This distance information is crucial for the UE because it directly affects the magnitude of the Doppler frequency offset and the applicability of the satellite pre-compensation value. It is understandable that UEs located at the beam center typically receive relatively more accurate signals, while the farther away the UE is, the greater the Doppler frequency offset of the signal may be, and the effect of satellite pre-compensation will be weakened, requiring additional receiver compensation from the UE.

[0059] In some embodiments of this application, the UE determines its straight-line distance from the beam center based on the beam center location information in the received first message, combined with its own real-time positioning data, through triangulation, distance formula calculation, or positioning services provided by a geographic information system (GIS). For example, using spherical trigonometry, given the latitude and longitude of the satellite beam center and the UE's latitude and longitude, the great circle distance between the two points can be calculated.

[0060] To accurately calculate the distance between the UE and the beam center, the UE utilizes high-precision positioning technologies, such as multi-base station positioning, differential GPS, or the BeiDou system, to obtain more accurate location information. This improves the accuracy of distance calculation with the beam center. For high-speed moving UEs or communication scenarios with extremely high requirements, more accurate location information can significantly improve the effectiveness of Doppler frequency offset compensation and reduce the impact on signal quality caused by UE position errors.

[0061] Before determining the distance between the user equipment and the beam center position of the satellite in response to the first message, the following steps may also be performed: receiving a second ephemeris broadcast message from the satellite, wherein the second ephemeris broadcast message is used to carry the beam center position and ephemeris information of the satellite.

[0062] The second ephemeris broadcast message is a broadcast message sent by the satellite. Its main purpose is to provide the user equipment with the current beam center position and ephemeris information of the satellite. It is understood that in a satellite communication system, the position and motion state of the satellite will change over time, and the beam center position will also change accordingly. Therefore, the UE can obtain the latest beam center position and ephemeris information through the second ephemeris broadcast message in order to accurately calculate the distance between the UE and the beam center and to perform accurate compensation for Doppler frequency offset.

[0063] Specifically, the UE periodically listens to the satellite's broadcast channel and receives a second ephemeris broadcast message containing the satellite beam center position and ephemeris information. This broadcast is periodic, ensuring that the UE can update the satellite's dynamic information in a timely manner. It should be noted that the satellite's ephemeris information includes, but is not limited to, orbital parameters, position, velocity, and predicted trajectory for a future period of time, while the beam center position is the geometric center of the currently broadcast beam.

[0064] In addition, the second ephemeris broadcast message may also contain one or more satellite positioning parameters, such as longitude, latitude, altitude, velocity vector, etc. After receiving this information, the UE can use a pre-set algorithm (such as spherical trigonometry, GPS positioning algorithm or dedicated Doppler frequency offset calculation model) to calculate the straight-line distance between itself and the satellite beam center.

[0065] Step S206: If the distance is greater than a preset threshold, perform post-compensation on the frequency offset of the received downlink signal based on the first compensation value.

[0066] In step S206 above, the preset threshold is a critical distance value defined between the UE and the center of the satellite beam. It is used to determine whether the UE needs additional receiver post-compensation. If the threshold is exceeded, the UE is considered to be at the edge of the beam. The Doppler frequency offset may be significant due to the difference in relative speed between the UE and the satellite. The satellite pre-compensation may not be sufficient to completely offset the frequency offset effect.

[0067] Post-compensation refers to the UE further adjusting the receiving frequency based on the first compensation value and its specific location and speed information to compensate for the remaining Doppler frequency offset. For UEs at the beam edge, relying solely on satellite pre-compensation may not completely eliminate the frequency offset effect. Therefore, the UE needs to perform post-compensation to ensure correct demodulation of the signal and communication quality.

[0068] In some embodiments of this application, post-compensation can be performed by: determining a second compensation value corresponding to the Doppler frequency shift between the satellite and the satellite; and performing post-compensation on the frequency offset of the downlink signal based on the first compensation value and the second compensation value.

[0069] The second compensation value is independently calculated by the UE based on its own position, velocity (including angular velocity and linear velocity), and received satellite ephemeris information to compensate for Doppler frequency offset. Compared with the first compensation value, the second compensation value more accurately reflects the Doppler frequency offset of the UE's location, especially when the UE is far from the satellite beam center, i.e., the distance is greater than a preset threshold. The calculation and application of the second compensation value enable the UE to effectively compensate for the gap left by satellite pre-compensation, ensuring the accuracy of signal reception.

[0070] To achieve accurate frequency compensation, the second compensation value can be determined by: obtaining ephemeris information from the second ephemeris broadcast message; and determining the second compensation value based on the ephemeris information.

[0071] Specifically, the UE uses its own velocity (including current velocity and predicted velocity), position information, and satellite position and velocity information received through the second ephemeris broadcast message to calculate the current Doppler frequency offset (second compensation value) between itself and the satellite based on the physical mathematical model of Doppler frequency shift.

[0072] It should be noted that, to improve the accuracy and efficiency of the calculation, the UE can employ a multi-sensor data fusion method, combining data from sensors such as GPS and IMU (Inertial Measurement Unit) to perform more accurate position and velocity estimation, and then calculate the Doppler frequency offset based on these estimates. Specifically: Step 1: Collect sensor data.

[0073] GPS module: The UE's GPS receiver periodically captures signals from multiple GPS satellites and decodes the navigation message information, including satellite positions, clock information, and orbital parameters, to calculate the UE's latitude and longitude coordinates and altitude.

[0074] IMU module: The UE's inertial measurement unit continuously monitors the device's three-dimensional acceleration, angular velocity, and possible magnetometer readings, providing the UE's instantaneous motion state data, including linear acceleration, angular velocity changes, and direction information.

[0075] Step 2: Data preprocessing and filtering.

[0076] Noise filtering: Digital filters (such as low-pass filters) are used to denoise the raw data from GPS and IMU, reducing the impact of external environmental factors (such as vibration and electromagnetic interference) on the measurement data.

[0077] Data synchronization: Ensure that the timestamps of GPS and IMU data are consistent by using a high-precision internal clock and external synchronization signals, such as NTP (Network Time Protocol) or reference satellite time signals, to avoid data time alignment errors.

[0078] Step 3: Multi-sensor data fusion.

[0079] Kalman filtering: A Kalman filter model is established to combine the position information provided by GPS and the velocity information provided by IMU for real-time state estimation and prediction. The Kalman filter can effectively combine the advantages of both sensors, while handling random errors and system biases, and outputting a more accurate position and velocity estimate.

[0080] Complementary Filter: A complementary filter is a simple data fusion method that uses a weighted average of GPS and IMU data. It utilizes GPS to provide long-period, low-frequency location information and IMU to provide high-frequency, short-period velocity information. The complementary filter can provide stable and accurate UE status information in a short time.

[0081] Step 4: Calculate the Doppler frequency offset.

[0082] The second compensation value is obtained by substituting the fused UE position and velocity data, as well as the satellite position and velocity from the satellite ephemeris information, into the Doppler frequency offset calculation formula.

[0083] In addition, the UE can also use historical communication data for statistical analysis to predict future Doppler frequency offset trends, adjust compensation strategies in advance, and reduce the uncertainty of signal reception.

[0084] To improve the stability and efficiency of signal reception, post-compensation can be performed based on a first compensation value and a second compensation value in the following way: determine the difference between the first compensation value and the second compensation value; and use the difference to adjust the frequency offset of the downlink signal.

[0085] In some embodiments of this application, the combined compensation value of the first compensation value and the second compensation value calculated by the UE, such as the difference between the two (i.e., the difference value), is used to adjust the local oscillator frequency of its receiver. Specifically, the UE first obtains the first compensation value of satellite pre-compensation from the first ephemeris broadcast message, then calculates the second compensation value itself, and finally combines the two to adjust the receiving frequency to compensate for the Doppler frequency offset in the downlink signal. This hybrid compensation method utilizes the advantages of satellite pre-compensation while also compensating for the shortcomings of satellite pre-compensation at beam-edge UEs. It should be noted that, considering that the relative speed between the UE and the satellite may change over time, the UE can periodically update the first compensation value and the second compensation value and calculate a new difference value.

[0086] To optimize the post-compensation process, the UE can employ adaptive filtering technology to dynamically adjust the weights of the first and second compensation values ​​based on real-time received signal quality feedback (such as SNR and BER) to achieve the best compensation effect. For example, if the UE detects poor signal quality, it means that the Doppler frequency offset is large. In this case, the weight of the second compensation value can be increased to strengthen the compensation on the UE side. Conversely, if the signal quality is good, the weight of the second compensation value can be appropriately reduced to save the UE's processing resources.

[0087] In some embodiments of this application, if the distance is less than or equal to a preset threshold, it is determined that post-compensation will no longer be performed.

[0088] Specifically, when the UE determines that the distance between itself and the satellite beam center is less than or equal to a preset threshold, it stops performing any Doppler frequency offset compensation for received signals. This relies on the compensation results from the satellite transmitter. The theoretical basis for this is that the satellite pre-compensation is based on the Doppler frequency offset calculation at the beam center location. For UEs located near the beam center region, this pre-compensation is sufficient to cope with the Doppler frequency offset effect, and no additional compensation is required from the UE. This decision is based on confidence in the effectiveness of the satellite pre-compensation, while also taking into account the additional power consumption and computational load that the UE's side-back compensation may bring.

[0089] In some embodiments of this application, the UE can establish a threshold monitoring mechanism. When the distance between the UE and the beam center exceeds a preset threshold and the duration reaches a preset duration, the UE initiates post-compensation. Once the distance returns to within the preset threshold, the UE automatically disables the post-compensation function. This automated control mechanism can effectively adjust the UE's signal processing strategy based on the real-time relative position between the UE and the satellite, thereby reducing power consumption and improving communication efficiency.

[0090] In addition, when the UE crosses a preset threshold, it can adopt a smooth transition strategy instead of immediately turning on or off post-compensation. For example, when the UE approaches the preset threshold, the UE begins to gradually increase the weight of post-compensation until it fully enters the beam edge region. Similarly, when the UE returns to the beam center region, the UE can gradually reduce the weight of post-compensation and eventually rely entirely on the satellite's pre-compensation. This smooth transition strategy helps maintain the continuity and stability of signal reception and avoids a sudden drop in communication quality.

[0091] Through steps S202 to S206 above, a hybrid compensation method is adopted. By leveraging the synergistic effect of the satellite and the user equipment (UE), the global view of the satellite and the local precise location information of the UE are utilized to dynamically adjust the compensation mechanism, thereby improving communication quality. This achieves the technical effects of reducing terminal power consumption and improving signal stability. Furthermore, it solves the technical problem in the Doppler frequency offset compensation schemes used in related technologies, where the method of using transmitter compensation or receiver compensation cannot effectively balance the accuracy of satellite compensation and the power consumption of terminal compensation.

[0092] Figure 3 This is a flowchart of another Doppler frequency shift compensation method according to an embodiment of this application, such as... Figure 3 As shown, the method includes: In step S302, the satellite determines a first compensation value corresponding to the Doppler frequency shift between the satellite and multiple user equipments within the beam coverage area, wherein the first compensation value is used to pre-compensate the downlink signal transmitted to the user equipment.

[0093] Step S304: Send a first message carrying a first compensation value to the user equipment. The first message is used to instruct the first user equipment to perform post-compensation on the frequency offset of the received downlink signal using the first compensation value. The first user equipment includes user equipment among a plurality of user equipment whose distance from the beam center position of the satellite is greater than a preset threshold.

[0094] In some embodiments of this application, the first message includes a first ephemeris broadcast message carrying ephemeris information.

[0095] In some embodiments of this application, the following steps may also be performed: sending a second ephemeris broadcast message carrying the beam center position to the user equipment, wherein the second ephemeris broadcast message is used to instruct the user equipment to determine the distance to the beam center position.

[0096] It should be noted that, Figure 3 Preferred embodiments of the shown examples can be found in [reference needed]. Figure 2 The corresponding solutions in the illustrated embodiments will not be described in detail here.

[0097] Figure 4This is a schematic diagram of satellite beam coverage for a Doppler shift compensation method according to an embodiment of this application, as shown below. Figure 4 As shown, this illustrates three terminals under satellite beam coverage, positioned at different points within the beam: UE1 is at the center of the beam, UE2 is at the edge of the coverage area, and UE3 is at the center. (Combined with...) Figure 4 The following explanation will be provided with reference to some specific embodiments: 1) Taking the downlink signal of the satellite system service link as an example; 2) When the satellite transmits downlink signals, pre-compensation is performed at the transmitting end, that is, based on its orbital parameters and the center position of the current beam coverage, the Doppler frequency offset is calculated and pre-compensation is performed within the current beam coverage area; 3) The satellite sends the compensation value (i.e., the first compensation value) to the terminals within its coverage area via a broadcast message carrying ephemeris information (i.e., the first ephemeris broadcast message), such as SIB19 or SIB31 in the 3GPP technical standard or other similar ephemeris broadcast messages. There are no restrictions on the message type. 4) The satellite will send the beam center location to the terminals within its coverage area via a broadcast message carrying ephemeris information (i.e., the second ephemeris broadcast message); 5) After receiving the broadcast message, the terminal can obtain the exact location of the beam center. The terminal can obtain its current location through positioning methods such as GPS, and then determine the distance between the terminal and the beam center. 6) Terminal preset distance beam center distance threshold (i.e. preset distance); 7) If the threshold is within the range, the terminal is considered to be in the center area of ​​the beam coverage, and the Doppler frequency offset pre-compensated by the satellite transmitter is considered to meet the terminal's reception requirements. The terminal will no longer perform post-compensation at the receiver. 8) If the threshold value is outside the beam coverage edge area, the terminal is considered to be in the edge area of ​​the beam coverage. The Doppler frequency offset pre-compensated by the satellite transmitter is considered to be insufficient to meet the terminal's reception requirements. The terminal needs to perform post-compensation at the receiver. 9) If it is a terminal in an edge area, the terminal performs post-compensation as follows: Based on the terminal's current location, speed information, and received ephemeris information, calculate the Doppler frequency offset (i.e., the second compensation value), and calculate the difference between this value and the Doppler frequency offset value received from the broadcast message. This difference is the actual Doppler frequency offset value to be post-compensated. Adjust the receiving frequency with this difference for post-compensation.

[0098] Figure 5 This is a structural diagram of a Doppler frequency shift compensation device according to an embodiment of this application, as shown below. Figure 5 As shown, the device includes: The receiving module 502 is used for the user equipment to receive a first message sent by the satellite, wherein the first message carries a first compensation value corresponding to the Doppler frequency shift between the satellite and the user equipment, and the first compensation value is used to pre-compensate the downlink signal sent by the satellite. The first determining module 504 is used to determine the distance between the user equipment and the beam center position of the satellite in response to the first message; The compensation module 506 is used to perform post-compensation on the frequency offset of the received downlink signal based on a first compensation value when the distance is greater than a preset threshold.

[0099] It should be noted that, Figure 5 The Doppler frequency shift compensation device shown is used to perform... Figure 2 The Doppler frequency shift compensation method shown is therefore Figure 2 The relevant explanations in the Doppler shift compensation method also apply to Figure 5 The Doppler frequency shift compensation device shown will not be described in detail here.

[0100] Figure 6 This is a structural diagram of another Doppler frequency shift compensation device according to an embodiment of this application, as shown below. Figure 6 As shown, the device includes: The second determining module 602 is used to determine a first compensation value corresponding to the Doppler frequency shift between the satellite and multiple user equipments within the beam coverage area, wherein the first compensation value is used to pre-compensate the downlink signal transmitted to the user equipment; The sending module 604 is used to send a first message carrying a first compensation value to the user equipment. The first message is used to instruct the first user equipment to perform post-compensation on the frequency offset of the received downlink signal using the first compensation value. The first user equipment includes a user equipment among a plurality of user equipment whose distance from the beam center position of the satellite is greater than a preset threshold.

[0101] It should be noted that, Figure 6 Another Doppler shift compensation device shown is used to perform... Figure 4 The Doppler frequency shift compensation method shown is therefore Figure 4 The relevant explanations in the Doppler shift compensation method also apply to Figure 6 The Doppler shift compensation device in the image will not be described in detail here.

[0102] This application also provides an electronic device, which includes a memory and a processor, wherein the memory is used to store program instructions; the processor is connected to the memory and is used to execute the steps of the Doppler frequency shift compensation method implemented in various embodiments of this application.

[0103] This application also provides a non-volatile storage medium including a stored computer program, wherein the device containing the non-volatile storage medium executes the steps of the Doppler shift compensation method in various embodiments of this application by running the computer program.

[0104] This application also provides a computer program product, including computer instructions that, when executed by a processor, implement the steps of the Doppler frequency shift compensation method in various embodiments of this application.

[0105] This application also provides a computer program that, when executed by a processor, implements the steps of the Doppler frequency shift compensation method in various embodiments of this application.

[0106] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0107] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0108] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0109] 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 units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0110] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0111] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. 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 a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0112] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for compensating for Doppler frequency shift, characterized in that, include: The user equipment receives a first message from the satellite, wherein the first message carries a first compensation value corresponding to the Doppler frequency shift between the satellite and the user equipment, and the first compensation value is used to pre-compensate the downlink signal transmitted by the satellite; In response to the first message, the distance between the user equipment and the beam center of the satellite is determined; If the distance is greater than a preset threshold, the frequency offset of the received downlink signal is post-compensated based on the first compensation value.

2. The method according to claim 1, characterized in that, The method further includes: if the distance is less than or equal to a preset threshold, determining that the post-compensation will no longer be performed.

3. The method according to claim 1, characterized in that, When the distance is greater than a preset threshold, post-compensation is performed on the frequency offset of the received downlink signal based on the first compensation value, including: Determine the second compensation value corresponding to the Doppler frequency shift between the satellite and the satellite; The frequency offset of the downlink signal is post-compensated based on the first compensation value and the second compensation value.

4. The method according to claim 3, characterized in that, The post-compensation for the frequency offset of the downlink signal based on the first compensation value and the second compensation value includes: Determine the difference between the first compensation value and the second compensation value; The frequency offset of the downlink signal is adjusted using the difference.

5. The method according to claim 3, characterized in that, Before determining the distance between the user equipment and the beam center position of the satellite in response to the first message, the method further includes: The system receives a second ephemeris broadcast message from the satellite, wherein the second ephemeris broadcast message carries the beam center position and ephemeris information of the satellite.

6. The method according to claim 5, characterized in that, Determining the second compensation value corresponding to the Doppler frequency shift between the satellite and the satellite includes: Obtain the ephemeris information from the second ephemeris broadcast message; The second compensation value is determined based on the ephemeris information.

7. The method according to claim 1, characterized in that, The first message includes a first ephemeris broadcast message sent by the satellite carrying ephemeris information.

8. A method for compensating for Doppler frequency shift, characterized in that, include: The satellite determines a first compensation value corresponding to the Doppler frequency shift between multiple user equipments within the beam coverage area, wherein the first compensation value is used to pre-compensate the downlink signal transmitted to the user equipment; A first message carrying the first compensation value is sent to the user equipment, wherein the first message is used to instruct the first user equipment to perform post-compensation on the frequency offset of the received downlink signal using the first compensation value, and the first user equipment includes user equipment among the plurality of user equipment whose distance from the beam center position of the satellite is greater than a preset threshold.

9. The method according to claim 8, characterized in that, The first message includes a first ephemeris broadcast message carrying ephemeris information.

10. The method according to claim 8, characterized in that, The method further includes sending a second ephemeris broadcast message carrying the beam center position to the user equipment, wherein the second ephemeris broadcast message is used to instruct the user equipment to determine the distance to the beam center position.

11. A Doppler frequency shift compensation device, characterized in that, include: The receiving module is used for the user equipment to receive a first message sent by the satellite, wherein the first message carries a first compensation value corresponding to the Doppler frequency shift between the satellite and the user equipment, and the first compensation value is used to pre-compensate the downlink signal sent by the satellite; The first determining module is configured to determine the distance between the user equipment and the beam center position of the satellite in response to the first message; The compensation module is used to perform post-compensation on the frequency offset of the received downlink signal based on the first compensation value when the distance is greater than a preset threshold.

12. A Doppler frequency shift compensation device, characterized in that, include: The second determining module is used for the satellite to determine a first compensation value corresponding to the Doppler frequency shift between the satellite and multiple user equipments within the beam coverage area, wherein the first compensation value is used to pre-compensate the downlink signal transmitted to the user equipment; The sending module is configured to send a first message carrying the first compensation value to the user equipment, wherein the first message is configured to instruct the first user equipment to perform post-compensation on the frequency offset of the received downlink signal using the first compensation value, and the first user equipment includes user equipment among the plurality of user equipment whose distance from the beam center position of the satellite is greater than a preset threshold.

13. An electronic device, characterized in that, include: A memory and a processor, wherein the memory is used to store program instructions; the processor is connected to the memory and is used to execute the Doppler frequency shift compensation method according to any one of claims 1 to 7, or to execute the Doppler frequency shift compensation method according to any one of claims 8 to 10.

14. A non-volatile storage medium, characterized in that, The non-volatile storage medium includes a stored computer program, wherein the device containing the non-volatile storage medium executes the Doppler frequency shift compensation method according to any one of claims 1 to 7, or executes the Doppler frequency shift compensation method according to any one of claims 8 to 10, by running the computer program.

15. A computer program product comprising computer instructions, characterized in that, When the computer instructions are executed by the processor, they implement the Doppler frequency shift compensation method according to any one of claims 1 to 7, or perform the Doppler frequency shift compensation method according to any one of claims 8 to 10.

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