Feed frequency offset compensation method and communication system

Abstract

The invention discloses a feed frequency offset compensation method and a communication system. The method comprises the following steps: a satellite communication management module obtains ephemeris information of a satellite and position information of a gateway station, and determines a first Doppler frequency offset of a feed link between the satellite and the gateway station according to the ephemeris information and the position information; obtaining a test frequency offset obtained by performing frequency estimation on a measurement signal transmitted on the feed link, and determining a feed frequency offset of the feed link according to the test frequency offset and the first Doppler frequency offset; and transmitting the feed frequency offset to the compensation module. The compensation module receives a message sent by the satellite communication management module; detecting whether the information contains the feed frequency offset of the feed link; and under the condition that the message contains the feed frequency offset, performing frequency offset compensation on the signal transmitted on the user link according to the feed frequency offset. According to the invention, the technical problem of feed frequency offset caused by unstable clock due to improvement of the working frequency of the feed link is solved.

Description

Technical Field

[0001] The present application relates to the technical field of satellite communication, and in particular, to a feeder frequency offset compensation method and a communication system. Background Art

[0002] A satellite communication system generally includes a user link and a feeder link, where: the user link is mainly a wireless link between a satellite and a user, and generally operates in frequency bands such as L (1 - 2 GHz), S (2 - 4 GHz), C (4 - 8 GHz), Ku (12 - 18 GHz), and Ka (27 - 40 GHz); while the feeder link is mainly a wireless link between a satellite and a gateway station, and generally operates in frequency bands such as C, X (8 - 12 GHz), Ku, and Ka. And for both communication satellites in transparent transponder mode and those in regeneration processing mode, the operating frequency of the feeder link is generally higher than that of the user link.

[0003] Currently, with the continuous increase in satellite communication capacity, the demand for the transmission bandwidth of the feeder link is also increasing continuously, which makes the operating frequency band of the feeder link continuously increase. However, when the feeder link operates in the high-frequency band, although it can provide a relatively wide operating bandwidth, the feeder frequency offset caused by the clock stability index cannot be ignored. Especially for communication satellites in transparent transponder mode, due to the high operating frequency of the feeder link, with the clock frequency stability index unchanged, the feeder frequency offset will increase exponentially with the increase in the operating frequency. This will also bring a large feeder frequency offset to the user link after frequency conversion and transponder, directly affecting the performance of the user link and even resulting in poor connectivity of the user link.

[0004] In view of the above problems, no effective solution has been proposed yet. Summary of the Invention

[0005] Embodiments of the present application provide a feeder frequency offset compensation method and a communication system to at least solve the technical problem of feeder frequency offset caused by unstable clock due to the increase in the operating frequency of the feeder link.

[0006] According to one aspect of the embodiments of the present application, a feeder frequency offset compensation method is provided, which is applied to a satellite communication management module and includes: obtaining the ephemeris information of a satellite and the position information of a gateway station, and determining the first Doppler frequency offset of the feeder link between the satellite and the gateway station based on the ephemeris information and the position information; obtaining the test frequency offset obtained by frequency estimation of the measurement signal transmitted on the feeder link, and determining the feeder frequency offset of the feeder link based on the test frequency offset and the first Doppler frequency offset; transmitting the feeder frequency offset to a compensation module, where the feeder frequency offset is used to perform frequency offset compensation on the signal transmitted on the user link, and the user link is a communication link between a terminal and a satellite.

[0007] Optionally, determining the first Doppler frequency offset of the feeder link according to the ephemeris information and the position information includes: obtaining the operating frequency f of the feeder link c ; According to the satellite's ephemeris information and the location information of the gateway station, determine the radial relative velocity v between the satellite and the gateway station r ; According to the operating frequency f c , radial relative velocity v r and the preset light speed c, the first Doppler frequency offset f of the feeder link is determined according to the following formula d :

[0008] Optionally, the feed frequency deviation includes: a downlink feed frequency deviation, and the operating frequency of the feed link includes: an uplink frequency and a downlink frequency, wherein obtaining a test frequency deviation obtained by frequency estimation of a measurement signal transmitted on the feed link, and determining the feed frequency deviation of the feed link based on the test frequency deviation and the first Doppler frequency deviation includes: obtaining a first downlink transmission frequency f for sending a measurement signal to a gateway station c_DL , and the downlink receiving frequency f when the gateway receives the measurement signal r_DL ; According to the first downlink receiving frequency f r_DL and downlink transmission frequency f c_DL , the test frequency deviation of the feeder link is obtained according to the following formula: f error =f r_DL -f c_DL ; Based on the test frequency deviation f error and the first Doppler frequency shift f d , determine the downlink feeding frequency deviation of the feeder link according to the following formula: f e_DL =f error -f d .

[0009] Optionally, the feeding frequency deviation includes: a bidirectional feeding frequency deviation, wherein a test frequency deviation obtained by frequency estimation of a measurement signal transmitted on the feeder link is obtained, and the feeding frequency deviation of the feeder link is determined based on the test frequency deviation and the first Doppler frequency deviation, and further includes: an uplink transmission frequency f when receiving the measurement signal sent by the gateway station c_UL , and forward the measurement signal in frequency conversion according to the preset forwarding ratio λ; according to the uplink sending frequency f c_UL , forwarding ratio λ, downlink feed frequency deviation f e_DL , the first Doppler frequency shift f d , determine the second downlink receiving frequency of the measurement signal after frequency conversion at the gateway station according to the following formula: f′ r_DL =λ(f c_UL +f d_UL )-f e +f d_UL ; According to the second downlink receiving frequency f' r_DL , uplink transmission frequency fc_UL 、Radial relative velocity v r 、Forwarding ratio λ and the preset speed of light c, and determine the two-way feed frequency offset of the feed link according to the following formula:

[0010] Optionally, the method further includes: calling the on-path measurement and control system to test the second Doppler frequency offset f' of the feed link d ; According to the first Doppler frequency offset f' d and the second Doppler frequency offset f d , determine the feed frequency offset according to the following formula: f e = f' d - f d .

[0011] Optionally, the measurement signal includes at least one of the following: single-carrier signal, spread-spectrum signal, where the center frequency of the single-carrier signal is within the edge operating frequency band of the feed link, and the center frequency band of the spread-spectrum signal is obtained by modulating the edge operating frequency band of the feed link according to the spreading code.

[0012] Optionally, the indication type of the feed frequency offset includes: absolute data indicated in physical units, relative data indicated using clock stability, and the clock stability is the quotient of the root mean square value of the feed frequency offset and the center operating frequency of the feed link.

[0013] Optionally, the compensation module includes: a base station having a communication connection with the gateway station or a terminal within the coverage area of the base station.

[0014] According to another aspect of the embodiments of the present application, there is also provided a feed frequency offset compensation method, which is applied to a compensation module and includes: receiving a message sent by a satellite communication management module; detecting whether the message contains the feed frequency offset of the feed link, where the feed link is a communication link between a satellite and a gateway station; and when the message contains the feed frequency offset, performing frequency offset compensation on the signal transmitted on the user link according to the feed frequency offset, where the user link is a communication link between a terminal and a satellite.

[0015] Optionally, receiving the message sent by the satellite communication management module includes: when the compensation module is a base station having a communication connection with the gateway station, receiving a control signaling sent by the satellite communication management module; when the compensation module is a terminal within the coverage area of the base station, obtaining a target message sent by the base station, where the type of the target message includes at least one of the following: master information block message, system information block message, radio resource control signaling.

[0016] Optionally, the indication types of the feed frequency offset include: absolute data indicated using physical units and relative data indicated using clock stability, where the clock stability is the quotient of the root mean square value of the feed frequency offset and the center operating frequency of the feed link. Among them, compensating for the frequency offset of the signal transmitted on the user link according to the feed frequency offset includes: when the indication type of the feed frequency offset is absolute data, compensating for the frequency offset of the signal transmitted on the user link according to the absolute data; when the indication type of the feed frequency offset is relative data, compensating for the frequency offset of the signal transmitted on the user link according to the product of the relative data and the operating frequency of the feed link.

[0017] Optionally, the method further includes: when the compensation module is a terminal within the coverage range of the base station, determining a first frequency ratio between the operating frequency of the feed link and the operating frequency of the user link, where the frequency ratio includes at least one of the following: a first frequency ratio of the uplink operating frequency of the user link to the downlink operating frequency of the feed link, a second frequency ratio of the downlink operating frequency of the user link to the uplink operating frequency of the feed link; in the case where the first frequency ratio is greater than 1 or less than 1, taking the negative value of the product of the second frequency ratio and the feed frequency offset as the first uplink frequency compensation value, and compensating the signal transmitted on the user link according to the first uplink frequency compensation value; in the case where the first frequency ratio is equal to 1, taking the negative value of the feed frequency offset as the second uplink frequency compensation value, and compensating the signal transmitted on the user link according to the second uplink frequency compensation value; in the case where the second frequency ratio is greater than 1 or less than 1, taking the negative value of the product of the second frequency ratio and the feed frequency offset as the first downlink frequency compensation value, and compensating the signal transmitted on the user link according to the first downlink frequency compensation value; in the case where the second frequency ratio is equal to 1, taking the negative value of the feed frequency offset as the second downlink frequency compensation value, and compensating the signal transmitted on the user link according to the second downlink frequency compensation value.

[0018] According to another aspect of the embodiments of the present application, a communication system is further provided. The communication system includes: a satellite communication management module and a compensation module, and the compensation module includes: a base station having a communication connection with the gateway station or a terminal within the coverage range of the base station. Among them, the satellite communication management module is used for the feed frequency offset compensation method applied to the satellite communication management module; the compensation module is used to execute the feed frequency offset step method applied to the compensation module.

[0019] According to another aspect of the embodiments of the present application, an electronic device is further provided. The electronic device includes: a memory and a processor, where a computer program is stored in the memory, and the processor is configured to execute the above-mentioned feed frequency offset compensation method through the computer program.

[0020] In the embodiments of the present application, the satellite communication management module determines the first Doppler frequency offset of the feeder link by acquiring the ephemeris information of the satellite and the location information of the gateway station, calculates the true feeder frequency offset by combining the measured frequency offset obtained from the frequency estimation of the feeder link measurement signal, and applies the frequency offset information to the compensation mechanism of the user link signal, achieving the technical effect of accurately measuring and compensating the frequency error caused by clock instability in the high-frequency feeder link of the satellite communication system, achieving the purpose of improving the transmission quality of the user link signal and enhancing the connectivity and stability of the communication link, and further solving the technical problem of the feeder frequency offset caused by clock instability due to the increase in the operating frequency of the feeder link. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments and descriptions thereof of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0022] Figure 1 is a schematic structural diagram of an optional communication system provided according to an embodiment of the present application;

[0023] Figure 2 is a schematic flowchart of an optional feeder frequency offset compensation method according to an embodiment of the present application;

[0024] Figure 3 is a schematic flowchart of another optional feeder frequency offset compensation method according to an embodiment of the present application;

[0025] Figure 4 is a schematic structural diagram of an optional feeder frequency offset compensation device according to an embodiment of the present application;

[0026] Figure 5 is a schematic structural diagram of another optional feeder frequency offset compensation device according to an embodiment of the present application;

[0027] Figure 6 is a schematic structural diagram of an optional network device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0029] It should be noted that the terms "first", "second", etc. in the description, claims and drawings of this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of this application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0030] To better understand the embodiments of this application, the following is a translation and explanation of some nouns or terms that appear in the description process of the embodiments of this application:

[0031] The feeder link is an important communication link in a satellite communication system, mainly used for two-way communication between a satellite and a gateway station. Specifically, the gateway station sends control signals and data to the satellite through the feeder link, and the satellite then transmits the received data back to the gateway station through the feeder link. This two-way communication link ensures the normal operation of the satellite communication system and the reliable transmission of data.

[0032] Gateway station: It is the data center node of the satellite communication satellite-ground system, responsible for the distribution and collection of satellite communication service data, and can complete the exchange of internal data in the satellite communication network and the data routing of the external network.

[0033] Doppler Shift: It refers to the change in phase and frequency caused by the difference in propagation path when a mobile station moves in a certain direction at a constant rate. It reveals the law of change of wave properties during motion.

[0034] Embodiment 1

[0035] In a satellite communication system, when it comes to a communication satellite in transparent transponder mode, since the satellite itself does not decode and re-encode the data passing through it, but acts as a signal relay station to frequency-convert and forward the received signal. During this process, if there is a frequency offset error caused by clock instability in the feeder link (i.e., the link between the satellite and the ground gateway station), then this error will affect the signal frequency of the service link during the frequency-conversion and forwarding process of the satellite.

[0036] Specifically, when the operating frequency of the feeder link is very high (such as Ka band, Q / V band), even if the clock stability index remains unchanged (for example, 1 ppm), due to the increase in the operating frequency, the frequency offset error caused by clock instability will increase significantly. For example, at an operating frequency of 40 GHz, a 1 ppm clock instability will result in a frequency offset error of up to 40 kHz. Such a frequency offset error will be transmitted to the service link. That is, when the satellite performs frequency conversion and forwarding, if this error cannot be compensated correctly, it will directly affect the signal frequency received by the terminal, thereby affecting the demodulation performance and communication quality of the signal. Therefore, the frequency offset error may cause interference between subcarriers (especially in narrowband signals, such as NB-IoT), reduce the data transmission rate, and even in extreme cases, reduce the connectivity of the service link to the extent that normal communication is impossible.

[0037] In view of the above problems, an embodiment of the present application provides a communication system. Figure 1 FIG. 5 is a schematic structural diagram of an optional communication system 10 provided according to an embodiment of the present application, as Figure 1 shown. The communication system 10 at least includes: a satellite communication management module 11 (which may be a network control center or a satellite network operation control center), and a compensation module 12. Among them, the compensation module 12 includes: a base station 121 in communication connection with a gateway station 13 or a terminal 122 within the coverage area of the base station.

[0038] Among them, the gateway station 121 is an important part of the ground in the satellite communication system. It is the interface between the satellite and the ground network. Therefore, the gateway station 121 can receive signals from the satellite, convert them into a signal format suitable for ground network transmission, and then send them to the ground network. At the same time, it also converts the signals of the ground network into a format suitable for satellite transmission and then sends them to the satellite, thereby realizing communication between the satellite and the ground network. In addition, the base station 121 is a base station in the ground mobile communication network, which is used to communicate with the terminal 122 to connect the signal of the terminal 122 to the ground mobile communication network.

[0039] In the scenario of the integration of satellite communication and ground mobile communication, when a terminal needs to perform data transmission through satellite communication, the base station can first send the data to the core network of the ground network. The core network of the ground network then routes the data to the gateway station, and the gateway station sends the data to the original remote gateway station or terminal through the satellite.

[0040] When performing frequency offset compensation for the feeder link, the satellite communication management module 11 and the compensation module 12 in the communication system 10 each perform the following functions:

[0041] The above satellite communication management module 11 can execute the feeder frequency offset compensation method, that is, calculate the feeder frequency offset of the feeder link between the gateway station and the satellite, and transmit the feeder frequency offset to the compensation module 12. Among them,

[0042] the above compensation module 12 can then perform frequency offset compensation on the signals transmitted on the user link between the terminal 13 and the satellite according to the feeder frequency offset.

[0043] The feeder frequency offset compensation method executed by the satellite communication management module 11 will be described in detail below. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0044] Figure 2 is a schematic flowchart of an optional feeder frequency offset compensation method provided by an embodiment of the present application. As Figure 2 shown, the method includes the following steps S202 - S206, including:

[0045] Step S202, obtain the ephemeris information of the satellite and the location information of the gateway station, and determine the first Doppler frequency offset of the feeder link between the satellite and the gateway station according to the ephemeris information and the location information.

[0046] In the technical solution provided in the above step S202, the above ephemeris information is the precise orbital parameter information of the satellite, including but not limited to: the instantaneous position, instantaneous velocity, acceleration, etc. of the satellite; and the location information of the gateway station is the geographical location data of the gateway station, which includes but not limited to: the longitude and latitude coordinates, altitude, etc. of the gateway station. Furthermore, the satellite communication management module 11 can calculate the first Doppler frequency offset caused by the relative motion between the satellite and the gateway station based on this information, that is, the frequency change amount of the feeder link caused by the satellite motion state and the gateway station position.

[0047] Step S204, obtain the test frequency offset obtained by frequency estimation of the measurement signal transmitted on the feeder link, and determine the feeder frequency offset of the feeder link according to the test frequency offset and the first Doppler frequency offset.

[0048] In the technical solution provided in the above step S204, the above measurement signal is a signal specifically designed for frequency offset testing on the feeder link, and it can measure the frequency offset amount of the feeder link caused by various factors during the actual transmission process. Therefore, the satellite communication management module 11 determines the feeder frequency offset of the feeder link by obtaining the test frequency offset obtained by frequency estimation of the measurement signal transmitted on the feeder link, and based on the actually measured test frequency offset and the theoretically calculated first Doppler frequency offset, obtains the effective feeder frequency offset caused by the clock error.

[0049] Step S206: Transmit the feed frequency offset to the compensation module.

[0050] In the technical solution provided in the above step S206, the compensation module can perform frequency offset compensation on the signals transmitted on the user link (i.e., the communication link between the terminal and the satellite) after frequency conversion and forwarding according to the feed frequency offset. That is to say, map the frequency offset of the feed link to the frequency offset value of the user link to effectively cancel the frequency offset caused by the unstable clock of the feed link and improve the transmission quality and communication performance of the user link signals.

[0051] Based on the solution defined in the above steps S202 to S206, it can be known that in the embodiment of the present application, the satellite communication management module 11 determines the first Doppler frequency offset of the feed link by obtaining the ephemeris information of the satellite and the position information of the gateway station, calculates the true feed frequency offset by combining the measured frequency offset obtained from the frequency estimation of the measurement signal of the feed link, and applies this frequency offset information to the compensation mechanism of the user link signal, achieving the technical effect of accurately measuring and compensating the frequency error caused by the unstable clock of the high-frequency feed link in the satellite communication system, and achieving the purpose of improving the transmission quality of the user link signal and enhancing the connectivity and stability of the communication link.

[0052] The following describes each step of the feed frequency offset compensation method in combination with a specific implementation process.

[0053] In satellite communication, when the distance between the satellite and the ground gateway station changes, that is, when the satellite has a radial velocity relative to the gateway station, the Doppler frequency offset will be generated:

[0054] If the satellite approaches the gateway station, the frequency of the received signal will increase (because the wavelength becomes shorter);

[0055] If the satellite moves away from the gateway station, the frequency of the received signal will decrease (because the wavelength becomes longer).

[0056] Therefore, the Doppler effect will cause the actual received frequency of the feed link to deviate from the expected value. Especially in the case of geostationary satellites and high-frequency bands, small velocity changes will also significantly affect the frequency stability. Therefore, accurately calculating the first Doppler frequency offset of the feed link is the key prerequisite for realizing effective frequency compensation and optimizing the communication link.

[0057] As an alternative implementation, in the technical solution provided in the above step S202, the satellite communication management module 11 can determine the first Doppler frequency offset of the feed link according to the following method, including:

[0058] The first step: Obtain the operating frequency f of the feed link c , where this operating frequency is the predetermined frequency when the feed link operates normally.

[0059] Step 2: Determine the radial relative velocity v between the satellite and the gateway station according to the ephemeris information of the satellite and the position information of the gateway station r . Therefore, this radial relative velocity v r reflects the rate of change of the distance between the satellite and the ground gateway station directly.

[0060] Step 3: According to the operating frequency f c , the radial relative velocity v r and the preset speed of light c, determine the first Doppler frequency offset f of the feeder link according to the following formula d :

[0061]

[0062] As an alternative implementation manner, in the technical solution provided in the above step S204, the type numbers of the measurement signals include the following two types:

[0063] (1) Single-carrier signal: Its center frequency is within the edge operating frequency band of the feeder link. That is to say, within the operating bandwidth of the feeder link, select an operating frequency point f r as the center frequency of the single-carrier signal, and f r is located at the edge of the operating frequency band of the feeder link, so as to avoid interfering with the signals within the operating bandwidth.

[0064] (2) Spread-spectrum signal: Its center frequency band is obtained by modulating the edge operating frequency band of the feeder link according to the spreading code. That is to say, within the operating bandwidth of the feeder link, select a bandwidth B0 as the center frequency band of the spread-spectrum signal, and B0 is located at the edge of the operating frequency band of the feeder link, so as to avoid interfering with the signals within the operating bandwidth. Among them, the spreading code can be selected from one of m-sequence, Gold code, ZC sequence or PN (Pseudorandom Noise) code, etc. In addition, the adjustment methods of the spreading code for the signal include but are not limited to: Direct Sequence Spread Spectrum (DSSS), Frequency Hopping Spread Spectrum (FHSS).

[0065] In addition, the object of configuring the measurement signal is not specifically limited in this application. It can be the ground gateway station or the satellite communication management module 11. And according to different objects of configuring the measurement signal, the determination process of the feeder frequency offset of the feeder link can be described in the following situations.

[0066] Method 1: The satellite communication management module 11 configures the measurement signal, then the satellite communication management module 11 can send the measurement signal to the gateway station through the downlink

[0067] In this case, the satellite communication management module 11 can determine the feed frequency offset of the feeder link according to the following steps, including:

[0068] The first step: Obtain the first downlink transmission frequency f of the measurement signal sent to the gateway station c_DL , and the downlink reception frequency f of the gateway station when receiving the measurement signal r_DL ;

[0069] The second step: Based on the first downlink reception frequency f r_DL and the downlink transmission frequency f c_DL , obtain the test frequency offset of the feeder link according to the following formula:

[0070] f error = f r_DL - f c_DL

[0071] The third step: Based on the test frequency offset f error and the first Doppler frequency offset f d , determine the downlink feed frequency offset of the feeder link according to the following formula:

[0072] f e_DL = f error - f d

[0073] Method 2: The gateway station configures the measurement signal, then the gateway station can send the measurement signal to the satellite communication management module 11 through the uplink; then the satellite communication management module 11 can perform frequency conversion and forwarding on the received measurement signal, and send the frequency-converted measurement signal to the gateway station through the downlink.

[0074] In this case, the satellite communication management module 11 can determine the feed frequency offset of the feeder link according to the following steps, including:

[0075] The first step: Receive the uplink transmission frequency f of the gateway station when sending the measurement signal c_UL , and perform frequency conversion and forwarding on the measurement signal according to the preset forwarding ratio λ;

[0076] The second step: Based on the uplink transmission frequency f c_UL , the forwarding ratio λ, the downlink feed frequency offset f e_DL , and the first Doppler frequency offset f d , determine the second downlink reception frequency of the gateway station receiving the frequency-converted measurement signal according to the following formula:

[0077] f' r_DL = λ(f c_UL + f d_UL ) - f e + f d_UL

[0078] Step 3: Based on the second downlink receiving frequency f′ r_DL , the uplink transmitting frequency f c_UL , the radial relative velocity v r , the forwarding ratio λ, and the preset speed of light c, determine the two-way feed frequency offset of the feed link according to the following formula:

[0079]

[0080] In addition, if the actual link frequency offset is not measured using a measurement signal, the satellite communication management module 11 can also determine the feed frequency offset of the feed link through the following method, including:

[0081] Step 1: Invoke the Telemetry, Tracking and Command System (TT&C) to test the second Doppler frequency offset f′ of the feed link d , where the Telemetry, Tracking and Command System in the satellite communication system is used to monitor the satellite status, determine the satellite position, and perform orbit control, and can also be used to measure the Doppler frequency offset of the feed link. Therefore, the satellite communication management module 11 can directly invoke this system to send uplink TT&C signals (for command upload and telemetry data request) and downlink telemetry signals (including satellite status information such as position, speed, and attitude) to the ground TT&C station for measurement.

[0082] Step 2: Based on the first Doppler frequency offset f′ d and the second Doppler frequency offset f d , determine the feed frequency offset according to the following formula:

[0083] f e = f′ d - f d

[0084] Therefore, several frequency offset measurement methods (unidirectional measurement, bidirectional measurement, and TT&C measurement) provided in the embodiments of the present application can accurately extract the influence of clock errors from a complex signal environment, thereby achieving more accurate measurement and compensation.

[0085] In addition, regarding the indication type of the feed frequency offset, considering the requirements and resource limitations in different scenarios, diverse solutions are provided, enhancing the operability and compatibility of the system. Specifically, the following indication forms are included:

[0086] (1) Absolute data indication: It uses physical units (such as Hz or kHz) to represent the feed frequency offset of the feed link.

[0087] Precise indication (higher quantization accuracy, e.g., 10 Hz): Under precise indication, it can be indicated by 15 bits. Among them, the first bit represents positive (e.g., "0" for negative, "1" for positive), and the other 14 bits indicate the specific value of the feed frequency offset.

[0088] Coarse indication (lower quantization accuracy, e.g., 100 Hz): Under coarse indication, it can also be indicated by 15 bits. Among them, the first bit represents positive (e.g., "0" for negative, "1" for positive), and the other 14 bits indicate the specific value of the feed frequency offset.

[0089] Among them, the difference between precise indication and coarse indication lies in the interval at which the feed frequency offset is segmented. For example, if the frequency offset error is -45 kHz, then in precise indication, it will be represented as -45000 Hz, and the smallest representable change is an integer multiple of 10 Hz; while in coarse indication, it will be represented as -45000 Hz (rounded to the nearest 100 Hz, which may be -45000 Hz or -45100 Hz, depending on the specific rounding rule).

[0090] (2) Relative data indication: It is relative data indicated using clock stability. Among them, clock stability is the quotient of the root mean square value of the feed frequency offset and the center operating frequency of the feed link, which reflects the percentage deviation or parts per million of the clock frequency relative to its nominal frequency.

[0091] Precise indication (higher quantization accuracy, e.g., 0.01 ppm): Under precise indication, it can be indicated by 9 bits. Among them, the first bit represents positive (e.g., "0" for negative, "1" for positive), and the other 8 bits indicate the specific value of the clock stability.

[0092] Coarse indication (lower quantization accuracy, e.g., 0.1 ppm): Under coarse indication, it can be indicated by 7 bits. Among them, the first bit represents positive (e.g., "0" for negative, "1" for positive), and the other 6 bits indicate the specific value of the clock stability.

[0093] It should be noted that when using relative data to indicate the feed frequency offset, the compensation module 12 can multiply the value indicated by the relative data by the uplink and downlink operating frequencies of the feed link to obtain the feed frequency offset caused by the clock error in the feed link.

[0094] After determining the feed frequency offset of the feed link through the above steps, the satellite communication management module 11 can transmit the calculated feed frequency offset to the compensation module 12, where the compensation module 12 includes: a base station (or base station equipment) having a communication connection with the gateway station, and terminals under the coverage of the base station.

[0095] When the compensation module 12 is the base station 121, the satellite communication management module 11 can transmit the feed frequency offset to the base station 121 by means of signaling; and then the base station 121 can perform frequency offset compensation on the signals transmitted on the user link according to the feed frequency offset.

[0096] When the compensation module 12 is the terminal 122 within the coverage area of the base station, the satellite communication management module 11 can first transmit the feed frequency offset to the base station 121 by means of signaling; then, the base station 121 transmits the feed frequency offset to the terminal 122 through the target message; and then the terminal 122 can perform frequency offset compensation on the signals transmitted on the user link according to the feed frequency offset. At the same time, the compensation for the frequency offset caused by the clock error of the feed link is increased.

[0097] Therefore, the dual compensation mechanism (ground base station, terminal) provided by the embodiments of the present application compensates the feed frequency, greatly improving the flexibility and adaptability of the communication system 10, and ensuring the stability and performance of the communication link even in a high-speed moving satellite scenario.

[0098] In addition, the feed frequency offset compensation method executed by the compensation module 12 will be described in detail. Figure 3 It is a schematic flowchart of an optional feed frequency offset compensation method provided by the embodiments of the present application. As Figure 3 shown, the method includes the following steps S302 - S306, including:

[0099] Step S302, receiving a message sent by the satellite communication management module.

[0100] As an optional implementation manner, in the technical solution provided in the above step S302, since the compensation module includes: the base station 121 having a communication connection with the gateway station or the terminal 122 within the coverage area of the base station 121. Therefore, the implementation process of the above technical solution includes:

[0101] When the compensation module 12 is the base station 121 having a communication connection with the gateway station, receiving a control signaling sent by the satellite communication management module 11. Among them, the control signaling includes but is not limited to: Link Control Message, Frequency Correction Request, Link Maintenance Message, etc.

[0102] When the compensation module 12 serves the terminal 122 within the coverage area of the base station 121, a target message sent by the base station 121 is obtained. Among them, the types of the target message include but are not limited to: Main Information Block (MIB) message, System Information Block (SIB) message, Radio Resource Control (RRC) signaling, etc. Among them: If the target message is an MIB message, relative data can be indicated within the message; if the target message is an SIB message or an RRC signaling message, relative data can be indicated within the message, or absolute data can be indicated within the message.

[0103] It should be noted that when the compensation module 12 serves the terminal 122 within the coverage area of the base station 121, before the terminal 122 receives the target message sent by the base station 121, it needs to first search for the downlink signal to perform downlink synchronization.

[0104] Step S304, detect whether the message contains the feed frequency offset of the feed link, where the feed link is the communication link between the satellite and the gateway station.

[0105] Step S306, when the message contains the feed frequency offset, perform frequency offset compensation on the signal transmitted on the user link according to the feed frequency offset. Among them, the user link is the communication link between the terminal and the satellite.

[0106] In the technical solution provided in the above step S306, since the indication types of the feed frequency include absolute data and relative data, the compensation module 12 can perform frequency offset compensation on the signal transmitted on the user link according to the rules, including:

[0107] When the indication type of the feed frequency offset is absolute data, the compensation module 12 can perform frequency offset compensation on the signal transmitted on the user link according to the absolute data;

[0108] When the indication type of the feed frequency offset is relative data, the compensation module 12 can perform frequency offset compensation on the signal transmitted on the user link according to the product of the relative data and the operating frequency of the feed link.

[0109] Particularly, when the satellite has a transparent transponder payload, the terminal 122 can compensate for the frequency offset caused by the clock of the feed link according to the following method, including:

[0110] Determine the first frequency ratio between the operating frequency of the feed link and the operating frequency of the user link, where the frequency ratio includes at least one of the following: the first frequency ratio α of the uplink operating frequency of the user link to the downlink operating frequency of the feed link, the second frequency ratio β of the downlink operating frequency of the user link to the uplink operating frequency of the feed link;

[0111] Case 1: The first frequency ratio is greater than 1 or less than 1, and the second frequency ratio is greater than 1 or less than 1. That is, there are a frequency error reduction effect and a frequency error amplification effect when the operating frequencies of the feeding link and the user link are subjected to frequency conversion processing.

[0112] In this case, the terminal 122 may use the negative value of the product of the second frequency ratio and the feeding frequency offset as the first uplink frequency compensation value, and compensate the signal transmitted on the user link according to the first uplink frequency compensation value; use the negative value of the product of the second frequency ratio and the feeding frequency offset as the first downlink frequency compensation value, and compensate the signal transmitted on the user link according to the first downlink frequency compensation value.

[0113] Case 2: The first frequency ratio is equal to 1 and the second frequency ratio is equal to 1. That is, there are no frequency error reduction effect and frequency error amplification effect when the operating frequencies of the feeding link and the user link are subjected to frequency conversion processing.

[0114] In this case, the terminal 122 may use the negative value of the feeding frequency offset as the second uplink frequency compensation value, and compensate the signal transmitted on the user link according to the second uplink frequency compensation value; use the negative value of the feeding frequency offset as the second downlink frequency compensation value, and compensate the signal transmitted on the user link according to the second downlink frequency compensation value.

[0115] Based on the solution defined in the above steps S302 to S306, it can be learned that in the embodiment of the present application, the compensation module receives the message sent by the satellite communication management module; detects whether the message contains the feeding frequency offset of the feeding link, and when the message contains the feeding frequency offset, compensates the frequency offset of the signal transmitted on the user link according to the feeding frequency offset. The technical effect of accurately measuring and compensating the frequency error caused by the unstable clock of the high-frequency feeding link in the satellite communication system is realized, and the purpose of improving the signal transmission quality of the user link and enhancing the connectivity and stability of the communication link is also achieved.

[0116] Embodiment 2

[0117] According to the embodiment of the present application, there is also provided a feeding frequency offset compensation device for implementing the feeding frequency offset compensation method in the satellite communication management module 11, as Figure 4 shown. The feeding frequency offset compensation device at least includes: a first determination unit 42, a second determination unit 44, and a transmission unit 46, where:

[0118] The first determination unit 42 is configured to obtain the ephemeris information of the satellite and the location information of the gateway station, and determine the first Doppler frequency offset of the feeding link between the satellite and the gateway station according to the ephemeris information and the location information;

[0119] A second determination unit 44, configured to obtain a test frequency offset obtained by performing frequency estimation on a measurement signal transmitted on a feeder link, and determine a feeder frequency offset of the feeder link according to the test frequency offset and a first Doppler frequency offset;

[0120] A transmission unit 46, configured to transmit the feeder frequency offset to a compensation module, where the feeder frequency offset is used to perform frequency offset compensation on a signal transmitted on a user link, and the user link is a communication link between a terminal and a satellite.

[0121] In addition, according to an embodiment of the present application, there is also provided a feeder frequency offset compensation device for implementing a feeder frequency offset compensation method in a terminal 122, as Figure 5 shown. The feeder frequency offset compensation device at least includes: a receiving module 52, a detection unit 54, and a compensation unit 56, where:

[0122] A receiving unit 52, configured to receive a message sent by a satellite communication management module;

[0123] A detection unit 54, configured to detect whether the message contains a feeder frequency offset of a feeder link, where the feeder link is a communication link between a satellite and a gateway station;

[0124] A compensation unit 56, configured to, when the message contains the feeder frequency offset, perform frequency offset compensation on a signal transmitted on a user link according to the feeder frequency offset, where the user link is a communication link between a terminal and a satellite.

[0125] It should be noted that each unit in the feeder frequency offset compensation device in the embodiment of the present application corresponds to each implementation step of the feeder frequency offset compensation method in Embodiment 1. Since the details not shown in this embodiment can be referred to Embodiment 1, they will not be elaborated here.

[0126] Embodiment 2

[0127] According to an embodiment of the present application, there is also provided a computer program product, which includes a computer program. When the computer program is executed by a processor, the feeder frequency offset compensation method in Embodiment 1 is implemented.

[0128] According to an embodiment of the present application, there is also provided a non-volatile storage medium, which includes a stored computer program. When the device where the non-volatile storage medium is located runs the computer program, the feeder frequency offset compensation method in Embodiment 1 is executed.

[0129] According to an embodiment of the present application, there is also provided a processor, which is used to run a computer program. When the computer program runs, the feeder frequency offset compensation method in Embodiment 1 is executed.

[0130] According to an embodiment of the present application, an electronic device is further provided. The electronic device includes: a memory and a processor. Among them, a computer program is stored in the memory, and the processor is configured to execute the feed frequency offset compensation method in Embodiment 1 through the computer program.

[0131] Optionally, when the computer program runs, it executes the following steps: The satellite communication management module obtains the ephemeris information of the satellite and the location information of the gateway station, and determines the first Doppler frequency offset of the feed link between the satellite and the gateway station based on the ephemeris information and the location information; obtains the test frequency offset obtained by frequency estimation of the measurement signal transmitted on the feed link, and determines the feed frequency offset of the feed link based on the test frequency offset and the first Doppler frequency offset; transmits the feed frequency offset to the compensation module, where the feed frequency offset is used to perform frequency offset compensation on the signal transmitted on the user link, and the user link is the communication link between the terminal and the satellite.

[0132] Optionally, when the computer program runs, it executes the following steps: The compensation module receives the message sent by the satellite communication management module; detects whether the message contains the feed frequency offset of the feed link, where the feed link is the communication link between the satellite and the gateway station; in the case where the message contains the feed frequency offset, performs frequency offset compensation on the signal transmitted on the user link based on the feed frequency offset, where the user link is the communication link between the terminal and the satellite.

[0133] As an optional implementation manner, the above network device may exist in the form of a mobile terminal, a computer terminal, or a similar computing device. Figure 6 A hardware structure block diagram of a network device for implementing the feed frequency offset compensation method is shown. As Figure 6 shown, the network device 60 may include one or more (shown as 602a, 602b,..., 602n in the figure) processors 602 (the processor 602 may include, but is not limited to, a processing device such as a microprocessor MCU or a programmable logic device FPGA), a memory 604 for storing data, and a transmission device 606 for communication functions. In addition, it may further include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the BUS bus), a network interface, a power supply, and / or a camera. Those of ordinary skill in the art can understand that Figure 6 the structure shown is only schematic, and it does not limit the structure of the above network device. For example, the network device 60 may further include more or fewer components than Figure 6 shown, or have a different configuration from Figure 6 shown.

[0134] It should be noted that one or more of the above-mentioned processors 602 and / or other data processing circuits can generally be referred to as "data processing circuits" herein. The data processing circuit can be embodied in software, hardware, firmware, or any combination thereof, in whole or in part. In addition, the data processing circuit can be a single independent processing module, or be incorporated in whole or in part into any one of the other elements in the network device 60. As involved in the embodiments of the present application, the data processing circuit is a kind of processor control (such as the selection of a variable resistance terminal path connected to an interface).

[0135] The memory 604 can be used to store software programs and modules of application software, such as the program instructions / data storage devices corresponding to the feed frequency offset compensation method in the embodiments of the present application. The processor 602 executes various functional applications and data processing by running the software programs and modules stored in the memory 604, that is, implements the vulnerability detection method of the above-mentioned application program. The memory 604 can include high-speed random access memory, and can also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memories. In some instances, the memory 604 can further include a memory remotely set relative to the processor 602, and these remote memories can be connected to the network device 60 through a network. Examples of the above-mentioned network include but are not limited to the Internet, enterprise intranet, local area network, mobile communication network, and combinations thereof.

[0136] The transmission device 606 is used to receive or send data via a network. Specific examples of the above-mentioned network can include a wireless network provided by the communication provider of the network device 60. In one instance, the transmission device 606 includes a network adapter (Network Interface Controller, NIC), which can be connected to other network devices through a base station and thus communicate with the Internet. In one instance, the transmission device 606 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0137] The display can be, for example, a touch-screen liquid crystal display (LCD), which enables the user to interact with the user interface of the network device 60.

[0138] The above-mentioned embodiment numbers are only for description and do not represent the advantages or disadvantages of the embodiments.

[0139] In the above embodiments of the present application, the descriptions of each embodiment have their own emphases. For parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0140] In several embodiments provided in the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the division of units can be a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed with each other can be through some interfaces. The indirect couplings or communication connections of units or modules can be in electrical or other forms.

[0141] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0142] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0143] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this 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 for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in each embodiment of the present application. The foregoing storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs that can store program codes.

[0144] The above is only the preferred embodiment of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A feed frequency offset compensation method, characterized in that, Applied to a satellite communication management module, including: Obtain the ephemeris information of a satellite and the location information of a gateway station, and determine a first Doppler frequency offset of a feeder link between the satellite and the gateway station according to the ephemeris information and the location information; Obtain a test frequency offset obtained by frequency estimation of a measurement signal transmitted on the feeder link, and determine a feeder frequency offset of the feeder link according to the test frequency offset and the first Doppler frequency offset; Transmit the feeder frequency offset to a compensation module, where the feeder frequency offset is used to perform frequency offset compensation on a signal transmitted on a user link, and the user link is a communication link between a terminal and the satellite.

2. The method according to claim 1, characterized in that, Determining the first Doppler frequency offset of the feeder link according to the ephemeris information and the location information includes: Obtain the operating frequency f of the feeding link c ; Determine the radial relative velocity v between the satellite and the gateway station based on the ephemeris information of the satellite and the position information of the gateway station r ; According to the working frequency f c , the radial relative velocity v r and the preset speed of light c, the first Doppler frequency offset f of the feed link is determined according to the following formula d :

3. The method according to claim 1, characterized in that The feeder frequency offset includes: a downlink feeder frequency offset, and the operating frequency of the feeder link includes: an uplink frequency, a downlink frequency. Wherein, obtaining a test frequency offset obtained by frequency estimation of a measurement signal transmitted on the feeder link, and determining the feeder frequency offset of the feeder link according to the test frequency offset and the first Doppler frequency offset includes: Obtain a first downlink transmission frequency f for transmitting the measurement signal to the gateway station c_DL , and a downlink reception frequency f when the gateway station receives the measurement signal r_DL ; According to the first downlink receiving frequency f r_DL and the downlink transmitting frequency f c_DL , the test frequency offset of the feeding link is obtained according to the following formula: f error = f r_DL - f c_DL ; According to the measured frequency offset f error and the first Doppler frequency offset f d , the downlink feeding frequency offset of the feeding link is determined according to the following formula: f e_DL = f error - f d .

4. The method according to claim 3, characterized in that, The feeder frequency offset includes: a bidirectional feeder frequency offset. Wherein, obtaining a test frequency offset obtained by frequency estimation of a measurement signal transmitted on the feeder link, and determining the feeder frequency offset of the feeder link according to the test frequency offset and the first Doppler frequency offset further includes: Receive the uplink transmission frequency f when the gateway station sends the measurement signal c_UL , and frequency-convert and forward the measurement signal according to a preset forwarding ratio λ; According to the uplink transmission frequency f c_UL , the forwarding ratio λ, the downlink feeding frequency offset f e_DL , the first Doppler frequency offset f d , determine the second downlink receiving frequency of the measured signal after frequency conversion received by the gateway station according to the following formula: f′ r_DL =λ(f c_UL +f d_UL )-f e +f d_UL ; According to the second downlink receiving frequency f′ r_DL , the uplink transmitting frequency f c_UL , the radial relative velocity v r , the forwarding ratio λ and the preset speed of light c, determine the two-way feed frequency offset of the feed link according to the following formula:

5. The method according to claim 1, characterized in that The method further includes: Call the associated path measurement and control system to test the second Doppler frequency offset f of the feeder link d ′ ; According to the first Doppler frequency offset f d ′ and the second Doppler frequency offset f d , determine the feeding frequency offset according to the following formula: f e = f d ′ - f d .

6. The method according to claim 1, characterized in that The measurement signal includes at least one of the following: a single-carrier signal, a spread-spectrum signal. Wherein, the center frequency of the single-carrier signal is within the edge operating frequency band of the feeder link, and the center frequency band of the spread-spectrum signal is obtained by modulating the edge operating frequency band of the feeder link according to a spreading code.

7. The method according to claim 1, wherein The indication type of the feeder frequency offset includes: absolute data indicated by a physical unit, relative data indicated by a clock stability. And the clock stability is the quotient of the root mean square value of the feeder frequency offset and the center operating frequency of the feeder link.

8. The method according to claim 1, characterized in that, The compensation module includes: a base station having a communication connection with the gateway station or a terminal within the coverage area of the base station.

9. A feed frequency offset compensation method, characterized in that, Applied to a compensation module, including: Receive a message sent by a satellite communication management module; Detect whether the message contains a feeder frequency offset of a feeder link, where the feeder link is a communication link between a satellite and a gateway station; When the message contains the feeder frequency offset, perform frequency offset compensation on a signal transmitted on a user link according to the feeder frequency offset, where the user link is a communication link between a terminal and the satellite.

10. The method according to claim 9, wherein The compensation module includes: a base station having a communication connection with the gateway station or a terminal within the coverage area of the base station. Wherein, receiving a message sent by a satellite communication management module includes: When the compensation module is a base station having a communication connection with the gateway station, receive a control signaling sent by a satellite communication management module; When the compensation module is a terminal within the coverage area of the base station, obtain a target message sent by the base station, where the type of the target message includes at least one of the following: master information block message, system information block message, radio resource control signaling.

11. The method according to claim 9, characterized in that, The indication type of the feed frequency offset includes: absolute data indicated using physical units, relative data indicated using clock stability, and the clock stability is the quotient of the root mean square value of the feed frequency offset and the center operating frequency of the feed link. Among them, performing frequency offset compensation on the signal transmitted on the user link according to the feed frequency offset includes: When the indication type of the feed frequency offset is the absolute data, perform frequency offset compensation on the signal transmitted on the user link according to the absolute data; When the indication type of the feed frequency offset is the relative data, perform frequency offset compensation on the signal transmitted on the user link according to the product of the relative data and the operating frequency of the feed link.

12. The method according to claim 10, wherein The method further includes: When the compensation module is a terminal within the coverage area of the base station, determine a first frequency ratio between the operating frequency of the feed link and the operating frequency of the user link, where the frequency ratio includes at least one of the following: a first frequency ratio of the uplink operating frequency of the user link to the downlink operating frequency of the feed link, a second frequency ratio of the downlink operating frequency of the user link to the uplink operating frequency of the feed link; In the case where the first frequency ratio is greater than 1 or less than 1, use the negative value of the product of the second frequency ratio and the feed frequency offset as a first uplink frequency compensation value, and perform compensation on the signal transmitted on the user link according to the first uplink frequency compensation value; in the case where the first frequency ratio is equal to 1, use the negative value of the feed frequency offset as a second uplink frequency compensation value, and perform compensation on the signal transmitted on the user link according to the second uplink frequency compensation value; In the case where the second frequency ratio is greater than 1 or less than 1, use the negative value of the product of the second frequency ratio and the feed frequency offset as a first downlink frequency compensation value, and perform compensation on the signal transmitted on the user link according to the first downlink frequency compensation value; in the case where the second frequency ratio is equal to 1, use the negative value of the feed frequency offset as a second downlink frequency compensation value, and perform compensation on the signal transmitted on the user link according to the second downlink frequency compensation value.

13. A communication system, characterized in that, The communication system includes: a satellite communication management module, a compensation module, and the compensation module includes: a base station having a communication connection with a gateway station or a terminal within the coverage area of the base station, where The satellite communication management module is configured to execute the feed frequency offset compensation method according to any one of claims 1 to 8; The compensation module is configured to execute the feed frequency offset compensation method according to any one of claims 9 to 12.

14. A network device, characterized in that, Includes: A memory and a processor, where a computer program is stored in the memory, and the processor is configured to execute the feed frequency offset compensation method according to any one of claims 1 to 12 through the computer program.

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