Reverse frequency synchronization method and device

Abstract

The invention provides a reverse frequency synchronization method which can be applied to the field of satellite communication. The method comprises: synchronizing a local clock and a reference frequency of a base station, the reference frequency being synchronized with a local clock of a terminal; the synchronized local clock of the base station is used as a reference clock for the base station to receive down-conversion; performing frequency offset compensation on the local receiving frequency by using the satellite beacon channel to obtain the compensated local receiving frequency; and synchronously receiving a reverse signal forwarded by the satellite according to the compensated local receiving frequency, wherein the reverse signal is a signal sent to the satellite by the terminal based on the synchronized clock signal. Therefore, under the synchronous reference frequency, the base station side accurately compensates for the frequency offset, and the accuracy of reverse frequency synchronization is improved. The invention also provides a reverse frequency synchronization device.

Description

Technical Field

[0001] The present disclosure relates to the field of satellite communication, and more particularly to a reverse frequency synchronization method and apparatus. Background Art

[0002] In satellite communication, reverse frequency synchronization ensures that when the signal sent by the terminal reaches the base station after being relayed by the satellite, the terminal can accurately receive and parse the signal, overcome the frequency offset caused by factors such as satellite movement, propagation delay, and the drift of the terminal's own crystal oscillator, ensure the communication quality, and enable reliable information transmission between the terminal and the base station on the reverse link.

[0003] Currently, for reverse frequency synchronization, generally the base station measures the frequency offset of the received signal and performs frequency offset compensation. Since the reverse signal power is low and thus the signal-to-noise ratio is low, there is a disadvantage of low measurement accuracy. Or the terminal measures the forward frequency offset for pre-compensation, but there will be frequency offsets in the terminal's receiving channel and transmitting channel, resulting in the inability to perform pre-compensation, making the frequency offset compensation inaccurate, the reverse frequency synchronization inaccurate, and unable to ensure the communication quality. Summary of the Invention

[0004] In view of at least one aspect of the above problems, embodiments of the present disclosure provide a reverse frequency synchronization method and apparatus for improving the accuracy of frequency offset compensation.

[0005] According to a first aspect of the present disclosure, there is provided a reverse frequency synchronization method applied to a base station. The method includes: synchronizing the local clock of the base station with a reference frequency, where the reference frequency is synchronized with the local clock of the terminal; using the synchronized local clock of the base station as the reference clock for down-conversion of the base station's reception; compensating the local reception frequency using the satellite beacon channel to obtain a compensated local reception frequency; and synchronizing the reception of the reverse signal relayed by the satellite according to the compensated local reception frequency; where the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal.

[0006] According to an embodiment of the present disclosure, the compensating the local reception frequency using the satellite beacon channel to obtain a compensated local reception frequency includes: measuring the frequency deviation between the base station and the satellite using the satellite beacon channel; and compensating the local reception frequency according to the frequency deviation to obtain the compensated local reception frequency.

[0007] According to an embodiment of the present disclosure, the method of measuring the frequency deviation between the base station and the satellite by using the satellite beacon channel includes: receiving the beacon signal sent by the satellite based on the local nominal frequency to obtain the actual frequency, where the local nominal frequency is set according to the nominal frequency of the beacon signal; and obtaining the frequency deviation according to the local nominal frequency and the actual frequency.

[0008] According to an embodiment of the present disclosure, the method of synchronizing the local clock of the base station with the reference frequency includes: using the second pulse signal of the reference frequency as the phase reference to adjust the local clock of the base station with the reference frequency, so as to synchronize the local clock of the base station with the reference frequency.

[0009] According to an embodiment of the present disclosure, the reference frequency includes at least one of the global positioning system signal frequency, the Beidou satellite navigation system signal frequency, and the global navigation satellite system signal frequency.

[0010] According to a second aspect of the present disclosure, a reverse frequency synchronization method is provided, which is applied to a terminal. The method includes: synchronizing the local clock of the terminal with a reference frequency, where the reference frequency is synchronized with the local clock of the base station; and based on the synchronized clock signal, sending a reverse signal to the satellite, so that the satellite forwards the reverse signal to the base station, and further enabling the base station to synchronously receive the reverse signal according to the compensated local reception frequency, where the compensated local reception frequency is obtained by the base station using the satellite beacon channel to perform frequency offset compensation on the local reception frequency.

[0011] According to an embodiment of the present disclosure, the step of sending a reverse signal to the satellite based on the synchronized clock signal includes: using the synchronized clock signal as the reference clock of the up-conversion module of the terminal; and sending the reverse signal to the satellite through the up-conversion module of the terminal.

[0012] According to an embodiment of the present disclosure, the method of synchronizing the local clock of the terminal with the reference frequency includes: using the second pulse signal of the reference frequency as the phase reference to adjust the local clock of the terminal with the reference frequency, so as to synchronize the local clock of the terminal with the reference frequency.

[0013] A third aspect of the present disclosure provides a reverse frequency synchronization device applied to a base station. The device includes: a first clock synchronization module for synchronizing the local clock of the base station with a reference frequency, where the reference frequency is synchronized with the local clock of a terminal; the synchronized local clock of the base station serves as the reference clock for down-conversion reception at the base station; a frequency offset compensation module for compensating the local reception frequency using a satellite beacon channel to obtain a compensated local reception frequency; and a first reverse synchronization module for synchronously receiving a reverse signal forwarded by a satellite according to the compensated local reception frequency; where the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal.

[0014] According to an embodiment of the present disclosure, the frequency offset compensation module includes a first frequency offset compensation unit for measuring the frequency offset between the base station and the satellite using the satellite beacon channel; and a second frequency offset compensation unit for compensating the local reception frequency according to the frequency offset to obtain the compensated local reception frequency.

[0015] According to an embodiment of the present disclosure, the first frequency offset compensation unit includes a first frequency offset measurement subunit for receiving a beacon signal sent by the satellite based on a local nominal frequency to measure the actual frequency; where the local nominal frequency is set according to the nominal frequency of the beacon signal; and a second frequency offset measurement subunit for obtaining the frequency offset according to the local nominal frequency and the actual frequency.

[0016] According to an embodiment of the present disclosure, the first clock synchronization module includes a first reference frequency unit for using the second pulse signal of the reference frequency as a phase reference to adjust the local clock of the base station and the reference frequency to synchronize the local clock of the base station with the reference frequency.

[0017] According to an embodiment of the present disclosure, the reference frequency includes at least one of: a Global Positioning System signal frequency, a BeiDou Navigation Satellite System signal frequency, and a Global Navigation Satellite System signal frequency.

[0018] A fourth aspect of the present disclosure provides a reverse frequency synchronization device applied to a terminal. The device includes: a second clock synchronization module for synchronizing the local clock of the terminal with a reference frequency, where the reference frequency is synchronized with the local clock of a base station; and a second reverse synchronization module for sending a reverse signal to a satellite based on the synchronized clock signal, so that the satellite forwards the reverse signal to the base station, and further enables the base station to synchronously receive the reverse signal according to the compensated local reception frequency; where the compensated local reception frequency is obtained by the base station compensating the local reception frequency using a satellite beacon channel.

[0019] According to an embodiment of the present disclosure, the second reverse synchronization module includes a signal reference unit for using the synchronized clock signal as the reference clock of the up-conversion module of the terminal; and a signal sending unit for sending the reverse signal to the satellite through the up-conversion module of the terminal.

[0020] According to an embodiment of the present disclosure, the second clock synchronization module includes a second reference frequency unit for using the second pulse signal of the reference frequency as a phase reference to adjust the local clock of the terminal and the reference frequency to synchronize the local clock of the terminal with the reference frequency.

[0021] A fifth aspect of the present disclosure provides an electronic device, including: one or more processors; a memory for storing one or more computer programs, wherein the above one or more processors execute the above one or more computer programs to implement the steps of the above method.

[0022] A sixth aspect of the present disclosure further provides a computer-readable storage medium having a computer program or instruction stored thereon, and when the computer program or instruction is executed by a processor, the steps of the above method are implemented.

[0023] A seventh aspect of the present disclosure further provides a computer program product, including a computer program or instruction, and when the computer program or instruction is executed by a processor, the steps of the above method are implemented.

[0024] In an embodiment of the present disclosure, due to the inaccurate existing frequency offset compensation and inaccurate reverse frequency synchronization, the communication quality cannot be guaranteed. By implementing the embodiments of the present disclosure, the local clock of the base station is synchronized with the reference frequency, wherein the reference frequency is synchronized with the local clock of the terminal; the synchronized local clock of the base station is used as the reference clock for down-conversion reception of the base station; the satellite beacon channel is used to compensate the frequency offset of the local reception frequency to obtain the compensated local reception frequency; and according to the compensated local reception frequency, the reverse signal forwarded by the satellite is synchronously received; wherein the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal. The base station uses the reference frequency for synchronization, the base station pre-measures the frequency offset from the satellite to the base station using the satellite beacon channel and compensates it, the terminal uses the same reference frequency as the base station for synchronization, and the frequency offset of the reverse signal sent by the terminal after being relayed by the satellite to reach the base station is very small, so as to achieve the purpose of frequency synchronization, avoiding the inaccuracy of measuring the frequency offset based on the reverse signal at the base station side, preventing the situation where the terminal cannot perform frequency offset pre-compensation, and accurately compensating the frequency offset at the base station side under the synchronized reference frequency, improving the accuracy of reverse frequency synchronization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, the above content and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0026] Figure 1 Schematically shows an application scenario diagram of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0027] Figure 2 Schematically shows a flowchart of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0028] Figure 3 Schematically shows a communication process interaction diagram of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0029] Figure 4 Schematically shows a flowchart of frequency offset compensation of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0030] Figure 5 Schematically shows a flowchart of frequency offset measurement of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0031] Figure 6 Schematically shows a signal forwarding schematic diagram of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0032] Figure 7 Schematically shows another flowchart of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0033] Figure 8 Schematically shows another flowchart of the reverse frequency synchronization method according to an embodiment of the present disclosure;

[0034] Figure 9 Schematically shows a structural block diagram of the reverse frequency synchronization device according to an embodiment of the present disclosure;

[0035] Figure 10 Schematically shows another structural block diagram of the reverse frequency synchronization device according to an embodiment of the present disclosure; and

[0036] Figure 11 Schematically shows a block diagram of an electronic device suitable for implementing the reverse frequency synchronization method according to an embodiment of the present disclosure. Detailed implementation manners

[0037] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it is obvious that one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

[0038] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0039] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0040] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but not be limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0041] Embodiments of the present disclosure provide a reverse frequency synchronization method, which is applied to a base station. The method includes: synchronizing the local clock of the base station with a reference frequency, where the reference frequency is synchronized with the local clock of the terminal; using the synchronized local clock of the base station as the reference clock for the base station to receive down-conversion; compensating the frequency offset of the local received frequency using a satellite beacon channel to obtain a compensated local received frequency; and synchronously receiving a reverse signal forwarded by the satellite according to the compensated local received frequency; where the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal.

[0042] Embodiments of the present disclosure provide a reverse frequency synchronization method, which is applied to a terminal. The method includes: synchronizing the local clock of the terminal with a reference frequency, where the reference frequency is synchronized with the local clock of the base station; and sending a reverse signal to the satellite based on the synchronized clock signal, so that the satellite forwards the reverse signal to the base station, and then the base station synchronously receives the reverse signal according to the compensated local received frequency; where the compensated local received frequency is obtained by the base station compensating the frequency offset of the local received frequency using a satellite beacon channel.

[0043] In an embodiment of the present disclosure, the base station is synchronized using a reference frequency. The base station pre-uses the satellite beacon channel to measure the frequency offset from the satellite to the base station and compensates for it. The terminal is synchronized using the same reference frequency as the base station. The reverse signal sent by the terminal has a very small frequency offset when it reaches the base station after being relayed by the satellite, thus achieving the purpose of frequency synchronization, avoiding the inaccuracy of the base station measuring the frequency offset based on the reverse signal, and preventing the situation where the terminal cannot perform pre-compensation of the frequency offset. At the synchronized reference frequency, the base station accurately compensates for the frequency offset, improving the accuracy of reverse frequency synchronization.

[0044] Figure 1 FIG. shows an application scenario diagram of the reverse frequency synchronization method according to an embodiment of the present disclosure.

[0045] As Figure 1 shown, the application scenario 100 according to this embodiment may include communication between terminals and a base station using a satellite. The network 104 serves as a medium for providing communication links between the terminals 101, 102, 103, the base station 105, and the satellite 106.

[0046] Users can use the terminals 101, 102, 103 to interact with the base station 105 through the network 104. The terminals 101, 102, 103 interact with the satellite 106 through the network 104, and the base station 105 interacts with the satellite 106 through the network 104 to receive or send messages, etc. Various communication client applications can be installed on the terminals 101, 102, 103, such as shopping applications, web browser applications, search applications, instant messaging tools, email clients, social platform software, etc. (for example only).

[0047] The terminals 101, 102, 103 can be various electronic devices with a display screen and supporting web browsing, including but not limited to smart phones, tablet computers, laptop portable computers, desktop computers, and so on.

[0048] The base station 105 can serve as an access device for a mobile communication system and communicate with the terminals 101, 102, 103 through wireless signals.

[0049] When the terminals 101, 102, 103 need to communicate with the satellite 106, the terminals 101, 102, 103 directly communicate with the satellite 106, and the satellite 106 then communicates with the base station 105 to access the terrestrial communication system, thereby realizing satellite communication of the terminals 101, 102, 103.

[0050] It should be understood that Figure 1 the numbers of terminals, networks, base stations, and satellites in

[0051] The following will be based on Figure 1 the described scenario, applied to a base station, and will describe in detail the reverse frequency synchronization method of the disclosed embodiments through Figures 2 to 6 the reverse frequency synchronization method of the disclosed embodiments.

[0052] Figure 2 FIG. schematically shows a flowchart of the reverse frequency synchronization method according to an embodiment of the present disclosure.

[0053] Figure 3 FIG. schematically shows a communication process interaction diagram of the reverse frequency synchronization method according to an embodiment of the present disclosure.

[0054] As Figure 2 , Figure 3 shown, the reverse frequency synchronization method of this embodiment is applied to a base station, and the method includes operations S210 to S230.

[0055] In operation S210, synchronize the local clock of the base station with the reference frequency, where the reference frequency is synchronized with the local clock of the terminal; the synchronized local clock of the base station is used as the reference clock for base station reception downconversion.

[0056] In the reverse link, the local clock of the terminal is synchronized with the reference frequency, and the synchronized clock signal (such as a 10M clock) is provided to the upconversion module (Digital Up Converter, DUC), so that there is no frequency offset in the reverse uplink signal, where the base station and the terminal are synchronized using the same reference frequency.

[0057] The local clock is calibrated based on the reference frequency, and the local clock adjusts its own frequency and phase according to the reference frequency. For example, the terminal calculates the difference between the local clock and the GPS time by receiving the pulse signal per second and time information in the GPS signal, and then adjusts the frequency of the local clock to make it consistent with the reference frequency to achieve frequency synchronization.

[0058] The local clock synchronized with the reference frequency provides accurate timing signals for each part in the terminal and the base station. For example, in a satellite communication terminal, the local clock provides a timing reference for operations such as signal modulation, demodulation, encoding, and decoding, ensuring that these operations can be performed at the correct time points. At the same time, it also provides a stable clock input for modules such as upconversion (DUC) and downconversion (DDC), ensuring the accuracy of the signal during the frequency conversion process.

[0059] The terminal and the base station continuously compare and monitor the local clock with the reference frequency. Once a frequency drift or deviation of the local clock is detected, it will be corrected according to the reference frequency. For example, when the frequency of the local clock changes due to factors such as the aging of the crystal oscillator and temperature changes, the frequency offset can be calculated by comparing it with the reference frequency, and corresponding measures can be taken to adjust the local clock to restore it to a state synchronized with the reference frequency, so as to ensure the normal operation of the terminal and the base station and the accuracy of signal processing.

[0060] According to an embodiment of the present disclosure, the reference frequency includes at least one of: the global positioning system signal frequency, the beidou satellite navigation system signal frequency, and the global navigation satellite system signal frequency.

[0061] Taking the global positioning system (GPS), beidou, or other global navigation satellite system (GNSS) signals as the reference frequency is to use the frequency information in the high-precision and high-stability signals transmitted by these satellite systems as the frequency reference for the corresponding electronic devices or systems of the terminal / base station.

[0062] Taking the GPS frequency as an example of the reference frequency, during the process of synchronizing the local clocks of the terminal and the base station with the GPS frequency, the GPS satellites send high-precision time signals, which are generated by the atomic clocks on the satellites. The terminal and the base station respectively synchronize their local clocks with the time of the GPS satellites by receiving the signals of multiple GPS satellites. Specifically, the terminal and the base station respectively receive the 1PPS (pulse per second) signal and the serial port time information in the GPS signal, calculate the difference between the local clock and the GPS time based on this information, and then adjust the frequency and deviation of the local clock to make it consistent with the GPS time. By comparing and adjusting the local clock with the reference frequency, the frequency and phase of the local clock are made consistent with the reference frequency, realizing the synchronization of the local clock based on the reference frequency, thereby obtaining a stable and accurate local clock signal.

[0063] According to an embodiment of the present disclosure, for the base station to synchronize the local clock of the base station with the reference frequency, it includes: using the second pulse signal of the reference frequency as the phase reference to adjust the local clock of the base station with the reference frequency to synchronize the local clock of the base station with the reference frequency.

[0064] According to an embodiment of the present disclosure, for the terminal to synchronize the local clock of the terminal with the reference frequency, it includes: using the second pulse signal of the reference frequency as the phase reference to adjust the local clock of the terminal with the reference frequency to synchronize the local clock of the terminal with the reference frequency.

[0065] Both the base station and the terminal use a reference frequency for synchronization. Taking the GPS frequency as an example of the reference frequency, the base station and the terminal adjust their local clocks with the second pulse signal (Pulse Per Second, PPS) of GPS as the phase reference. Specifically, both the base station and the terminal use the rising edge or falling edge of the PPS signal of GPS as the time reference to adjust their respective local clocks. In this way, the local clocks of the base station and the terminal are phase-aligned with the GPS frequency, thereby achieving frequency synchronization between the two. On the reverse link, the base station and the terminal have the same reference frequency, and the base station can accurately receive and process the signals sent by the terminal because they are in a good synchronization state in terms of frequency and phase, which helps to improve the communication quality and reliability.

[0066] In operation S220, the satellite beacon channel is used to perform frequency offset compensation on the local received frequency to obtain the compensated local received frequency.

[0067] Figure 4 Schematically shows the flowchart of frequency offset compensation for the reverse frequency synchronization method according to an embodiment of the present disclosure.

[0068] As Figure 4 shown, according to an embodiment of the present disclosure, in performing frequency offset compensation on the local received frequency using the satellite beacon channel in operation S220, operations S410 - S420 are included.

[0069] In operation S410, the satellite beacon channel is used to measure the frequency deviation between the base station and the satellite.

[0070] The satellite beacon channel is a channel in satellite communication used to transmit specific beacon signals, a specific frequency band or logical channel specifically allocated for transmitting beacon signals. The beacon signal in the satellite beacon channel has a specific format and characteristics, and is generally periodically transmitted by a transmitting end such as a base station or a satellite.

[0071] The base station can accurately adjust its own transmitting and receiving frequencies according to the beacon signal sent by the satellite beacon channel to ensure that the communication frequency with the satellite is accurate and error-free, and reduce the impact of frequency deviation on communication quality.

[0072] In operation S420, the local received frequency is compensated according to the frequency deviation.

[0073] After measuring the frequency deviation between the base station and the satellite through the satellite beacon channel, according to the measured frequency deviation, a compensation value for adjusting the local received frequency is determined. Usually, this compensation value is equal in magnitude and opposite in direction to the frequency deviation. For example, if the measured frequency deviation is +100 Hz (indicating that the received signal frequency is 100 Hz higher than the nominal frequency), then the compensation value is -100 Hz, and the local received frequency is compensated according to this compensation value.

[0074] The local oscillator is a key component for generating the local reception frequency. Compensation can be achieved by adjusting the frequency of the local oscillator. Most modern communication devices usually have adjustable parameters for the local oscillator, and its oscillation frequency can be changed through software control or hardware circuits. By adjusting the frequency of the local oscillator according to a determined compensation value, the local reception frequency can be made close to or equal to the correct frequency, thereby achieving compensation for the frequency deviation.

[0075] Figure 5 Schematically shows a flowchart of frequency offset measurement for a reverse frequency synchronization method according to an embodiment of the present disclosure.

[0076] As Figure 5 shown, according to an embodiment of the present disclosure, in operation S410 of measuring the frequency deviation between the base station and the satellite using the satellite beacon channel, operations S510 - S520 are included.

[0077] In operation S510, based on the local nominal frequency, receive the beacon signal sent by the satellite to measure the actual frequency; wherein, the local nominal frequency is set according to the nominal frequency of the beacon signal.

[0078] In satellite communication, the beacon signal is a reference signal with a specific frequency, used for functions such as system synchronization and calibration. The beacon signal of the satellite is generally a single - frequency signal. Since the beacon signal always exists and the received signal - to - noise ratio is very high, the measurement result can be very accurate.

[0079] Nominal frequency: This is the theoretical frequency value set in the design or specification of the beacon signal. It is a fixed and standard frequency parameter, usually determined during the system design stage and used as a reference benchmark for various frequency - related operations in the system.

[0080] Actual frequency: During the actual transmission of the beacon signal, due to the influence of various factors, such as the Doppler effect during signal propagation, clock deviation of the satellite or ground equipment, and changes in the characteristics of the transmission medium, etc., the actual frequency when the signal reaches the receiving end will change. This actually received frequency is the actual frequency.

[0081] When the base station receives the beacon signal, it demodulates and processes the signal according to the pre - set local nominal frequency However, since the actual frequency of the beacon signal when it reaches the base station is and there is a difference from the local nominal frequency used by the base station. Among them, the pre - set local nominal frequency is set according to the nominal frequency of the satellite's beacon signal, so that the local nominal frequency is consistent with the nominal frequency of the beacon signal.

[0082] In operation S520, a frequency deviation is obtained based on the local nominal frequency and the actual frequency.

[0083] Local nominal frequency and the actual frequency The difference between them is the frequency deviation between the satellite and the base station , by calculating the actual frequency and the local nominal frequency The difference, that is , the base station can obtain the frequency offset of the frequency deviation of the beacon signal, and the base station adjusts the local received frequency to for compensation to achieve frequency offset compensation.

[0084] In the embodiments of the present disclosure, the measurement of the frequency deviation is very important for the frequency synchronization and signal processing of the system. The base station can adjust its own received frequency or perform other related signal processing operations according to this frequency offset value to ensure that it can accurately receive and parse the beacon signal and subsequent other communication signals.

[0085] In operation S230, the reverse signal forwarded by the satellite is synchronously received according to the compensated local received frequency; wherein, the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal.

[0086] The base station pre-uses the on-board (satellite) satellite beacon channel to measure the frequency difference between the satellite and the base station and compensates the local received frequency to receive the reverse signal. Herein, "pre-" means that the base station can measure the frequency deviation between the satellite and the base station using the satellite beacon channel and perform compensation before sending the system broadcast signal to allow the terminal to access.

[0087] The base station is synchronized with the reference frequency. The base station pre-uses the satellite beacon channel to measure the frequency offset from the satellite to the base station and performs compensation. Then the terminal is also synchronized with the same reference frequency. When the signal sent by the terminal is forwarded by the satellite and reaches the base station, the frequency offset is very small, thereby achieving the purpose of frequency synchronization.

[0088] According to the embodiments of the present disclosure, the terminal sends a reverse signal to the satellite based on the synchronized clock signal, including: using the synchronized clock signal as the reference clock of the up-conversion module of the terminal; and sending a reverse signal to the satellite through the up-conversion module of the terminal.

[0089] The synchronized clock signal is the clock signal generated by the local clock of the terminal after synchronizing the local clock with the reference frequency. After synchronization, the local clock of the terminal serves as the reference clock for the up-conversion transmission of the terminal. The clock signal generated by the local clock is the product of synchronization with the reference frequency. Taking the synchronized clock signal as a 10M clock signal as an example, the 10M clock signal indicates that its frequency is 10 megahertz (10 MHz), that is, a signal with 10 million cycles generated per second. The 10M clock signal is a clock signal with a specific frequency obtained after the local clock is synchronized with the reference frequency. The reference frequency provides a benchmark for the synchronization of the local clock. The local clock adjusts its own frequency and phase to reach a synchronized state with the reference frequency, and then outputs a 10M clock signal. The accuracy and stability of the 10M clock depend on the precision and stability of the reference frequency.

[0090] It should be noted that in an actual application system, there may be a certain multiple or frequency division relationship between the synchronized clock signal (such as a 10M clock signal) and the reference frequency. For example, the reference frequency may be a higher frequency, such as 100M hertz, and the 10M clock signal is obtained by dividing it through a frequency divider to meet the requirements of the up-conversion module (DUC) or other system components for a clock signal with a specific frequency. Or the reference frequency undergoes a series of frequency syntheses and processing to obtain a 10M clock suitable for use in the application system. This multiple or frequency division relationship is determined according to the system design and specific requirements, aiming to reasonably utilize the reference frequency resources while ensuring system performance and providing appropriate clock signals for each module.

[0091] Exemplarily, the process of sending a reverse signal to a satellite through the up-conversion module (DUC) of the terminal is as follows:

[0092] (1) Clock driving and signal generation: The synchronized clock signal (such as a 10M clock signal) provides a stable time reference for the DUC. The internal circuit of the DUC generates a series of local oscillation signals with specific frequency and phase relationships under the drive of this clock signal. The frequency of the local oscillation signal is related to the frequency of the input baseband signal and the radio frequency to which it needs to be up-converted finally. For example, through circuits such as a phase-locked loop (PLL), operations such as multiplying, dividing, or mixing the 10M clock signal are performed to generate a local oscillation frequency that matches the radio frequency of the uplink signal.

[0093] (2) Baseband signal processing: The baseband signal input to the DUC first undergoes a series of processes such as filtering, amplification, encoding, etc. to ensure the signal quality and meet the transmission requirements. Then, according to the modulation method of the system (such as amplitude modulation, frequency modulation, or phase modulation, etc.), the information of the baseband signal is loaded onto the local oscillation signal generated by the clock (such as a 10M clock). For example, in a digital communication system, when using quadrature amplitude modulation (QAM), the digital baseband signal is mapped to the constellation points on the complex plane, and then through the mixing operation with the local oscillation signal, the spectrum of the baseband signal is shifted to the radio frequency band.

[0094] (3) Up-conversion operation: After the baseband signal modulates the local oscillation signal, the DUC mixes the modulated signal with the local oscillation signal through circuits such as mixers. The result of mixing is to shift the spectrum of the baseband signal from the original low-frequency band to a higher radio frequency band, achieving the up-conversion of the signal. Since the local oscillation signal is precisely controlled and generated by the synchronized clock signal, the up-converted signal has accurate frequency and phase, meeting the requirements for sending to the satellite.

[0095] (4) Power amplification and filtering: The up-converted signal usually has low power and needs to be amplified by a power amplifier to reach sufficient transmission power. At the same time, in order to suppress the spurious components and noise in the signal and ensure the spectral purity of the transmitted signal, a filter is used to filter the amplified signal. The parameters of the filter are also designed according to the system frequency characteristics determined by the synchronized clock signal to ensure that only the required reverse uplink signal frequency components can pass through and be sent to the satellite.

[0096] (5) Antenna transmission: The reverse uplink signal after power amplification and filtering is finally transmitted through the antenna to the satellite. The design and parameter selection of the antenna are also related to the frequency characteristics of the system to ensure that the signal can be effectively radiated into space and has good directivity and gain, thereby improving the receiving sensitivity and reliability of the signal reaching the satellite.

[0097] In the embodiments of the present disclosure, Figure 6 Schematically shows a signal forwarding schematic diagram of the reverse frequency synchronization method according to the embodiments of the present disclosure, as Figure 6As shown, the reverse signal includes an uplink reverse signal and a downlink reverse signal. The uplink reverse signal has no deviation from the reference frequency after passing through the up-conversion module (DUC) at the terminal, but there will be a frequency deviation due to the frequency offset of the satellite transponder after passing through the satellite. When the downlink reverse signal is transmitted in reverse to the base station, the frequency offset of the beacon signal and the downlink reverse signal have the same frequency offset because they are both the frequency offset between the satellite transponder and the reference frequency. Since the base station has measured the frequency offset between the satellite and the base station based on the satellite beacon channel and performed receive frequency compensation, the downlink reverse signal of the terminal has a very small frequency offset after being received by the base station, achieving the purpose of frequency synchronization. It should be noted that in Figure 6 RX DUC (Receive Digital Up Converter) represents the digital up-converter at the receiving end, that is, the up-conversion module when the terminal or the base station is the receiving end, which is used to convert the received digital signal from a lower frequency to a higher frequency. TX DUC (Transmit Digital Up Converter) represents the digital up-converter at the transmitting end, that is, the up-conversion module when the terminal or the base station is the transmitting end, which converts the digital signal to be transmitted from a lower frequency to a higher frequency so as to send the signal through transmitting devices such as antennas. RX DUC corresponds to TX DUC, and they are both important modules for realizing signal frequency conversion in the communication system. Only one is for the receiving end and the other is for the transmitting end, and they cooperate together to realize a complete communication link.

[0098] The following will be based on Figure 1 the described scenario, applied to the terminal, and will describe in detail the reverse frequency synchronization method of the disclosed embodiments through Figure 7

[0099] Figure 7 Another flowchart of the reverse frequency synchronization method according to an embodiment of the present disclosure is schematically shown.

[0100] As Figure 3 , 7 shown, the reverse frequency synchronization method of this embodiment is applied to the terminal, and this method includes operation S710 to operation S720.

[0101] In operation S710, synchronize the local clock of the terminal with the reference frequency, where the reference frequency is synchronized with the local clock of the base station.

[0102] In operation S720, based on the synchronized clock signal, send a reverse signal to the satellite so that the satellite forwards the reverse signal to the base station, and further enable the base station to synchronously receive the reverse signal according to the compensated local receive frequency; where the compensated local receive frequency is obtained by the base station using the satellite beacon channel to perform frequency offset compensation on the local receive frequency.

[0103] According to an embodiment of the present disclosure, in operation S720 of sending a reverse signal to the satellite based on the synchronized clock signal, it includes: using the synchronized clock signal as the reference signal of the up-conversion module of the terminal; and sending the reverse signal to the satellite through the up-conversion module of the terminal.

[0104] According to an embodiment of the present disclosure, in operation S710 of synchronizing the local clock of the terminal with the reference frequency, it includes: using the second pulse signal of the reference frequency as the phase reference to adjust the local clock of the terminal and the reference frequency to synchronize the local clock of the terminal with the reference frequency.

[0105] It should be noted that for the specific embodiments adopted in operations S710 to S720, reference can be made to the corresponding embodiments in the above operations S210 to S230, and no redundant elaboration will be made here.

[0106] The following will be based on Figure 1 the described scenario, and through Figure 8 describe in detail the reverse frequency synchronization method of the disclosed embodiments.

[0107] Figure 8 Another flowchart of the reverse frequency synchronization method according to an embodiment of the present disclosure is schematically shown.

[0108] As Figure 3 , 8 shown, the reverse frequency synchronization method of this embodiment includes operations S810 to S870.

[0109] In operation S810, the base station synchronizes the local clock of the base station with the reference frequency; the synchronized local clock of the base station is used as the reference clock for the base station to receive down-conversion;

[0110] In operation S820, the terminal synchronizes the local clock of the terminal with the reference frequency; the synchronized local clock of the terminal is used as the reference clock for the terminal to send up-conversion;

[0111] In operation S830, the satellite sends a beacon signal to the base station;

[0112] In operation S840, the base station uses the satellite beacon channel to receive the beacon signal, measures the frequency offset and compensates the local receiving frequency for the frequency offset to obtain the compensated local receiving frequency;

[0113] In operation S850, the terminal sends a reverse signal to the satellite based on the synchronized clock signal;

[0114] In operation S860, the satellite receives the reverse signal and forwards the reverse signal to the base station;

[0115] In operation S870, the base station receives the reverse signal forwarded by the satellite according to the compensated local receiving frequency.

[0116] It should be noted that for the specific embodiments adopted in Operations S810 to S870, reference may be made to the corresponding embodiments in the above-mentioned Operations S210 to S230, and no redundant elaboration will be provided here.

[0117] Based on the above reverse frequency synchronization method and applied to a base station, the present disclosure also provides a reverse frequency synchronization device. The following will be combined with Figure 9 to describe this device in detail.

[0118] Figure 9 A structural block diagram of a reverse frequency synchronization device according to an embodiment of the present disclosure is schematically shown.

[0119] As Figure 9 shown, the reverse frequency synchronization device 900 of this embodiment includes a first clock synchronization module 910, a frequency offset compensation module 920, and a first reverse synchronization module 930.

[0120] The first clock synchronization module 910 is used to synchronize the local clock of the base station with a reference frequency, where the reference frequency is synchronized with the local clock of the terminal; the synchronized local clock of the base station serves as the reference clock for base station reception downconversion. In one embodiment, the first clock synchronization module 910 can be used to perform Operation S210 described above, and details will not be repeated here.

[0121] The frequency offset compensation module 920 is used to perform frequency offset compensation on the local reception frequency using a satellite beacon channel to obtain a compensated local reception frequency. In one embodiment, the frequency offset compensation module 920 can be used to perform Operation S220 described above, and details will not be repeated here.

[0122] The first reverse synchronization module 930 is used to synchronously receive a reverse signal forwarded by a satellite according to the compensated local reception frequency; where the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal. In one embodiment, the first reverse synchronization module 930 can be used to perform Operation S230 described above, and details will not be repeated here.

[0123] According to an embodiment of the present disclosure, the first clock synchronization module 910 includes a first reference frequency unit, which uses the second pulse signal of the reference frequency as a phase reference to adjust the local clock of the base station and the reference frequency to synchronize the local clock of the base station with the reference frequency.

[0124] According to an embodiment of the present disclosure, the reference frequency includes at least one of: a global positioning system signal frequency, a Beidou satellite navigation system signal frequency, and a global navigation satellite system signal frequency.

[0125] According to an embodiment of the present disclosure, the frequency offset compensation module 920 includes a first frequency offset compensation unit for measuring the frequency deviation between the base station and the satellite by using a satellite beacon channel; and a second frequency offset compensation unit for compensating the local received frequency according to the frequency deviation to obtain a compensated local received frequency.

[0126] According to an embodiment of the present disclosure, the first frequency offset compensation unit includes a first frequency offset measurement subunit for receiving a beacon signal transmitted by the satellite based on the local nominal frequency to measure the actual frequency; wherein the local nominal frequency is set according to the nominal frequency of the beacon signal; and a second frequency offset measurement subunit for obtaining the frequency deviation according to the local nominal frequency and the actual frequency.

[0127] According to an embodiment of the present disclosure, any multiple of the first clock synchronization module 910, the frequency offset compensation module 920, and the first reverse synchronization module 930 may be combined and implemented in one module, or any one of them may be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules may be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the first clock synchronization module 910, the frequency offset compensation module 920, and the first reverse synchronization module 930 may be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on chip, a system on substrate, a system on package, an application specific integrated circuit (ASIC), or any other reasonable way of integrating or packaging circuits, etc., implemented by hardware or firmware, or implemented in any one of the three implementation manners of software, hardware, and firmware, or in an appropriate combination of any several of them. Alternatively, at least one of the first clock synchronization module 910, the frequency offset compensation module 920, and the first reverse synchronization module 930 may be at least partially implemented as a computer program module, and when the computer program module is run, the corresponding functions may be executed.

[0128] Based on the above reverse frequency synchronization method applied to a terminal, the present disclosure further provides a reverse frequency synchronization device. The following will be combined with Figure 10 to describe the device in detail.

[0129] Figure 10 Schematically shows another structural block diagram of the reverse frequency synchronization device according to an embodiment of the present disclosure.

[0130] As Figure 10 shown, the reverse frequency synchronization device 1000 of this embodiment includes a second clock synchronization module 1010 and a second reverse synchronization module 1020.

[0131] The second clock synchronization module 1010 is used to synchronize the local clock of the terminal with the reference frequency, where the reference frequency is synchronized with the local clock of the base station. In one embodiment, the second clock synchronization module 1010 can be used to perform the operation S710 described above, which will not be elaborated here.

[0132] The second reverse synchronization module 1020 is used to send a reverse signal to the satellite based on the synchronized clock signal, so that the satellite forwards the reverse signal to the base station, and further enables the base station to synchronously receive the reverse signal according to the compensated local reception frequency; where the compensated local reception frequency is obtained by the base station using the satellite beacon channel to perform frequency offset compensation on the local reception frequency. In one embodiment, the second reverse synchronization module 1020 can be used to perform the operation S720 described above, which will not be elaborated here.

[0133] According to an embodiment of the present disclosure, the second clock synchronization module 1010 includes a second reference frequency unit, which is used to use the second pulse signal of the reference frequency as a phase reference to adjust the local clock of the terminal and the reference frequency, so as to synchronize the local clock of the terminal with the reference frequency.

[0134] According to an embodiment of the present disclosure, the second reverse synchronization module 1020 includes a signal reference unit, which is used to use the synchronized clock signal as the reference clock of the up-conversion module of the terminal; and a signal sending unit, which is used to send a reverse signal to the satellite through the up-conversion module of the terminal.

[0135] According to an embodiment of the present disclosure, any multiple of the second clock synchronization module 1010 and the second reverse synchronization module 1020 can be combined and implemented in one module, or any one of them can be split into multiple modules. Or, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the second clock synchronization module 1010 and the second reverse synchronization module 1020 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on chip, a system on substrate, a system on package, an application specific integrated circuit (ASIC), or can be implemented by any other reasonable way of integrating or packaging circuits, etc., in hardware or firmware, or implemented in any one of the three implementation ways of software, hardware, and firmware, or in any appropriate combination of several of them. Or, at least one of the second clock synchronization module 1010 and the second reverse synchronization module 1020 can be at least partially implemented as a computer program module, and when the computer program module is run, it can execute the corresponding functions.

[0136] Figure 11A block diagram of an electronic device suitable for implementing a reverse frequency synchronization method according to an embodiment of the present disclosure is schematically shown.

[0137] As Figure 11 shown, the electronic device 1100 according to an embodiment of the present disclosure includes a processor 1101, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1102 or a program loaded from a storage section 1108 into a random access memory (RAM) 1103. The processor 1101 may include, for example, a general-purpose microprocessor (e.g., CPU), an instruction set processor, and / or a related chipset, and / or a dedicated microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 1101 may also include on-board memory for caching purposes. The processor 1101 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0138] In the RAM 1103, various programs and data required for the operation of the electronic device 1100 are stored. The processor 1101, the ROM 1102, and the RAM 1103 are connected to each other via a bus 1104. The processor 1101 performs various operations of the method flow according to an embodiment of the present disclosure by executing the program in the ROM 1102 and / or the RAM 1103. It should be noted that the program may also be stored in one or more memories other than the ROM 1102 and the RAM 1103. The processor 1101 may also perform various operations of the method flow according to an embodiment of the present disclosure by executing the program stored in one or more memories.

[0139] According to an embodiment of the present disclosure, the electronic device 1100 may further include an input / output (I / O) interface 1105, and the input / output (I / O) interface 1105 is also connected to the bus 1104. The electronic device 1100 may further include one or more of the following components connected to the input / output (I / O) interface 1105: an input section 1106 including a keyboard, a mouse, etc.; an output section 1107 including, for example, a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1108 including a hard disk, etc.; and a communication section 1109 including a network interface card such as a LAN card, a modem, etc. The communication section 1109 performs communication processing via a network such as the Internet. A drive 1110 is also connected to the input / output (I / O) interface 1105 as needed. A removable medium 1111, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1110 as needed so that a computer program read from it can be installed into the storage section 1108 as needed.

[0140] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or may exist alone without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiments of the present disclosure is implemented.

[0141] According to an embodiment of the present disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, it may include but is not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In the present disclosure, the computer-readable storage medium may be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, apparatus, or device. For example, according to an embodiment of the present disclosure, the computer-readable storage medium may include the above-described ROM 1102 and / or RAM 1103 and / or one or more memories other than ROM 1102 and RAM 1103.

[0142] An embodiment of the present disclosure further includes a computer program product, which includes a computer program, and the computer program contains program code for executing the method shown in the flowchart. When the computer program product runs in a computer system, the program code is used to cause the computer system to implement the reverse frequency synchronization method provided by the embodiments of the present disclosure.

[0143] When the computer program is executed by the processor 1101, the above functions defined in the system / apparatus of the embodiments of the present disclosure are executed. According to an embodiment of the present disclosure, the above-described systems, apparatuses, modules, units, etc. may be implemented by computer program modules.

[0144] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices and magnetic storage devices. In another embodiment, the computer program may also be transmitted and distributed in the form of a signal on a network medium, and be downloaded and installed through the communication part 1109, and / or be installed from the removable medium 1111. The program code included in the computer program may be transmitted by any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0145] In such an embodiment, the computer program can be downloaded and installed from a network through the communication part 1109, and / or installed from the removable medium 1111. When the computer program is executed by the processor 1101, the above-described functions defined in the system of the embodiments of the present disclosure are executed. According to the embodiments of the present disclosure, the above-described systems, devices, apparatuses, modules, units, etc. can be implemented by computer program modules.

[0146] According to the embodiments of the present disclosure, the program code for executing the computer program provided by the embodiments of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level procedures and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages include, but are not limited to, such as Java, C++, python, the "C" language, or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (e.g., by connecting through the Internet using an Internet service provider).

[0147] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code, and the above-mentioned module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0148] Those skilled in the art can understand that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0149] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A reverse frequency synchronization method, applied to a base station, characterized in that: The method comprises: Synchronizing the local clock of the base station with a reference frequency, wherein the reference frequency is synchronized with the local clock of the terminal; the synchronized local clock of the base station is used as a reference clock for receiving down-conversion by the base station; Using the satellite beacon channel to compensate for the frequency deviation of the local receiving frequency to obtain a compensated local receiving frequency; and According to the compensated local receiving frequency, a reverse signal forwarded by a satellite is synchronously received; wherein the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal.

2. The method according to claim 1, characterized in that The method of using the satellite beacon channel to perform frequency offset compensation on the local receiving frequency to obtain the compensated local receiving frequency includes: Measuring a frequency deviation between the base station and the satellite using the satellite beacon channel; and The local receiving frequency is compensated according to the frequency deviation to obtain the compensated local receiving frequency.

3. The method according to claim 2, characterized in that The step of measuring the frequency deviation between the base station and the satellite by using the satellite beacon channel comprises: Based on the local nominal frequency, receiving the beacon signal sent by the satellite to measure the real frequency; wherein the local nominal frequency is set according to the nominal frequency of the beacon signal; and The frequency deviation is obtained according to the local nominal frequency and the true frequency.

4. The method according to claim 1, characterized in that: The synchronizing the local clock of the base station with a reference frequency includes: The pulse-per-second signal of the reference frequency is used as a phase reference to adjust the local clock of the base station and the reference frequency, so as to synchronize the local clock of the base station and the reference frequency.

5. The method according to claim 1, characterized in that The reference frequency includes: at least one of a global positioning system signal frequency, a Beidou satellite navigation system signal frequency, and a global navigation satellite system signal frequency.

6. A reverse frequency synchronization method, applied to a terminal, characterized in that: The method comprises: synchronizing a local clock of the terminal with a reference frequency, wherein the reference frequency is synchronized with a local clock of a base station; and Based on the synchronized clock signal, a reverse signal is sent to the satellite so that the satellite forwards the reverse signal to the base station, and then the base station synchronously receives the reverse signal according to the compensated local receiving frequency; wherein the compensated local receiving frequency is obtained by the base station using the satellite beacon channel to compensate for the frequency deviation of the local receiving frequency.

7. The method according to claim 6, characterized in that The sending of a reverse signal to the satellite based on the synchronized clock signal comprises: Using the synchronized clock signal as a reference clock for an up-conversion module of the terminal; and The reverse signal is sent to the satellite through the up-conversion module of the terminal.

8. The method according to claim 6, characterized in that The synchronizing the local clock of the terminal with a reference frequency includes: The pulse-per-second signal of the reference frequency is used as a phase reference to adjust the local clock of the terminal and the reference frequency, so as to synchronize the local clock of the terminal with the reference frequency.

9. A reverse frequency synchronization device, applied to a base station, characterized in that: The device comprises: A first clock synchronization module, used to synchronize the local clock of the base station with a reference frequency, wherein the reference frequency is synchronized with the local clock of the terminal; the synchronized local clock of the base station is used as a reference clock for receiving down-conversion by the base station; A frequency deviation compensation module, used to use the satellite beacon channel to perform frequency deviation compensation on the local receiving frequency to obtain the compensated local receiving frequency; and The first reverse synchronization module is used to synchronously receive a reverse signal forwarded by a satellite according to the compensated local receiving frequency; wherein the reverse signal is a signal sent by the terminal to the satellite based on the synchronized clock signal.

10. A reverse frequency synchronization device, applied to a terminal, characterized in that: The device comprises: a second clock synchronization module, configured to synchronize a local clock of the terminal with a reference frequency, wherein the reference frequency is synchronized with a local clock of a base station; and The second reverse synchronization module is used to send a reverse signal to the satellite based on the synchronized clock signal, so that the satellite forwards the reverse signal to the base station, and then the base station synchronously receives the reverse signal according to the compensated local receiving frequency; wherein the compensated local receiving frequency is obtained by the base station using the satellite beacon channel to compensate for the frequency deviation of the local receiving frequency.

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