Multipath transmission method, satellite, terminal and storage medium

Abstract

The invention relates to a multipath transmission method, a satellite, a terminal and a storage medium. The method is applied to a main satellite, a satellite-borne base station is arranged on the main satellite, and the method comprises the steps that a downlink synchronization time difference value is acquired, and the downlink synchronization time difference value is the time difference of arrival when downlink signals are sent to a terminal through a second link and a first link; the first link is a transmission link which is transparently forwarded between the main satellite and the terminal through the auxiliary satellite, and the second link is a direct transmission link between the main satellite and the terminal; based on the downlink synchronization time difference, sending a first path of downlink signal to the terminal through a first link at a first moment, and sending a second path of downlink signal to the terminal through a second link at a second moment; wherein the advance time of the first moment relative to the second moment is a downlink synchronization time difference value.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a multiplexing method, satellite, terminal and storage medium. Background Technology

[0002] In satellite scenarios, the channel between the satellite and the user is primarily direct-path, making it difficult to provide multipath channels for Multiple Input Multiple Output (MIMO) transmission. Therefore, MIMO transmission for satellites is currently lacking. Due to these limitations, satellites typically schedule only one beam to serve a single user, hindering further increases in user data transmission rates. Summary of the Invention

[0003] Therefore, it is necessary to provide a multiplexing method, satellite, terminal, storage medium, and program product to address the aforementioned technical problems.

[0004] In a first aspect, this application provides a multiplexing method applied to a master satellite, wherein the master satellite is equipped with an onboard base station, the method comprising:

[0005] The downlink synchronization time difference is obtained, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal.

[0006] Based on the downlink synchronization time difference, a first downlink signal is sent to the terminal through the first link at a first moment, and a second downlink signal is sent to the terminal through the second link at a second moment;

[0007] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0008] Secondly, this application also provides a multiplexing method applied to a terminal, the method comprising:

[0009] The downlink synchronization time difference is sent to the main satellite. The downlink synchronization time difference is the arrival time difference between the downlink signal sent through the second link and the downlink signal sent through the first link. The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal.

[0010] At the first target time domain location, the first downlink signal transmitted by the main satellite through the first link at the first moment, and the second downlink signal transmitted through the second link at the second moment;

[0011] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0012] Thirdly, this application also provides a multiplexing method applied to a terminal, the method comprising:

[0013] The uplink synchronization time difference is obtained, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; the first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0014] Based on the uplink synchronization time difference, a first uplink signal is sent to the main satellite through the first link at the third time, and a second uplink signal is sent to the main satellite through the second link at the fourth time;

[0015] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0016] Fourthly, this application also provides a multiplexing method applied to a main satellite, wherein the main satellite is equipped with an onboard base station, the method comprising:

[0017] The uplink synchronization time difference is sent to the terminal. The uplink synchronization time difference is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal.

[0018] At the second target time domain location, the terminal receives the first uplink signal transmitted by the terminal at the third time through the first link of the auxiliary satellite transparent relay, and the second uplink signal transmitted directly through the second link at the fourth time.

[0019] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0020] Fifthly, a main satellite is provided, wherein an onboard base station is provided, comprising: a memory, a transceiver, and a processor.

[0021] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations:

[0022] The downlink synchronization time difference is obtained, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal.

[0023] Based on the downlink synchronization time difference, a first downlink signal is sent to the terminal through the first link at a first moment, and a second downlink signal is sent to the terminal through the second link at a second moment;

[0024] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0025] Sixthly, a terminal is provided, comprising: a memory, a transceiver, and a processor.

[0026] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations:

[0027] The downlink synchronization time difference is sent to the main satellite. The downlink synchronization time difference is the arrival time difference between the downlink signal sent through the second link and the downlink signal sent through the first link. The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal.

[0028] At the first target time domain location, the first downlink signal transmitted by the main satellite through the first link at the first moment, and the second downlink signal transmitted through the second link at the second moment;

[0029] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0030] Seventhly, a terminal is provided, comprising: a memory, a transceiver, and a processor.

[0031] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations:

[0032] The uplink synchronization time difference is obtained, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; the first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0033] Based on the uplink synchronization time difference, a first uplink signal is sent to the main satellite through the first link at the third time, and a second uplink signal is sent to the main satellite through the second link at the fourth time;

[0034] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0035] Eighthly, a main satellite is provided, wherein an onboard base station is provided, comprising: a memory, a transceiver, and a processor.

[0036] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations:

[0037] The uplink synchronization time difference is sent to the terminal. The uplink synchronization time difference is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal.

[0038] At the second target time domain location, the terminal receives a first uplink signal transmitted through the first link at a third time and a second uplink signal transmitted through the second link at a fourth time.

[0039] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0040] Ninthly, a main satellite is provided, comprising:

[0041] The acquisition module is used to acquire the downlink synchronization time difference value, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal;

[0042] The transmitting module is configured to transmit a first downlink signal to the terminal via the first link at a first moment based on the downlink synchronization time difference, and to transmit a second downlink signal to the terminal via the second link at a second moment;

[0043] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0044] Tenthly, a terminal, comprising:

[0045] The transmitting module is used to send downlink synchronization time difference to the main satellite. The downlink synchronization time difference is the arrival time difference between the downlink signal transmitted through the second link and the downlink signal transmitted through the first link. The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0046] The receiving module is configured to receive, at the first target time domain location, a first downlink signal transmitted by the main satellite through the first link at a first moment, and a second downlink signal transmitted through the second link at a second moment;

[0047] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0048] Eleventhly, a terminal is provided, comprising:

[0049] The acquisition module is used to acquire the uplink synchronization time difference value, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; the first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal;

[0050] The transmitting module is configured to transmit a first uplink signal to the main satellite via the first link at a third time based on the uplink synchronization time difference, and to transmit a second uplink signal to the main satellite via the second link at a fourth time;

[0051] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0052] In the twelfth aspect, a main satellite is provided, including: a memory, a transceiver, and a processor.

[0053] The transmitting module is used to send an uplink synchronization time difference value to the terminal. The uplink synchronization time difference value is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0054] The receiving module is configured to receive, at a second target time domain location, a first uplink signal transmitted by the terminal through the first link at a third time, and a second uplink signal transmitted through the second link at a fourth time;

[0055] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0056] In a fourteenth aspect, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements at least one of the following methods:

[0057] The method as described in the first aspect or any embodiment thereof;

[0058] The method as described in the second aspect or any embodiment thereof;

[0059] The method described in the third aspect or any embodiment thereof;

[0060] The method described in the fourth aspect or any of its embodiments.

[0061] In a fifteenth aspect, this application also provides a computer program product comprising a computer program that, when executed by a processor, implements at least one of the following methods:

[0062] The method as described in the first aspect or any embodiment thereof;

[0063] The method as described in the second aspect or any embodiment thereof;

[0064] The method described in the third aspect or any embodiment thereof;

[0065] The method described in the fourth aspect or any of its embodiments.

[0066] The aforementioned multiplexing method, satellite, terminal, storage medium, and program product involve two links. The first link is a purely passive link between the primary satellite and the terminal via a secondary satellite, transparently relayed. The second link is a direct transmission link between the primary satellite and the terminal. Since the primary satellite can obtain the downlink synchronization time difference between sending downlink signals to the terminal via the second link and via the first link, it can send the first downlink signal via the first link at the first moment, with the downlink synchronization time difference preceding the second moment. It can also send the second downlink signal via the second link at the second moment. This allows the downlink signals sent by the primary satellite via two different links to arrive at the terminal simultaneously. This provides users with channel conditions for multi-stream transmission in a combination of regenerative and transparent transmission modes, enabling users to receive multi-stream data transmission from a single user through multi-satellite collaborative transmission after access, thereby improving the user's data transmission rate. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of a working mode in which the primary satellite and the secondary satellite simultaneously provide services to a single terminal, according to an embodiment of this application.

[0068] Figure 2This is a flowchart illustrating a multiplexing method for downlink transmission in an embodiment of this application.

[0069] Figure 3 This is a flowchart illustrating a multiplexing method for uplink transmission in an embodiment of this application.

[0070] Figure 4 A schematic diagram of the structure of a communication device provided in one embodiment;

[0071] Figure 5 This is a structural block diagram of a main satellite;

[0072] Figure 6 This is a structural block diagram of a terminal.

[0073] Figure 7 Here is a structural block diagram of another type of terminal;

[0074] Figure 8 This is a structural block diagram of another type of main satellite. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0076] In this embodiment of the invention, the term "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0077] Satellite mobile communication technologies typically provide data transmission services to a single user via a single satellite beam, which limits the transmission rate of a single user to the beam power and time-frequency resources. MIMO transmission technology, widely used in terrestrial networks, can effectively improve user transmission rates. However, due to the strong main path and lack of scatterers in satellite channels, MIMO technology, which relies on multipath propagation, is difficult to apply in satellite mobile communication scenarios. Using multiple beams from multiple satellites to serve the same user is a potential operating mode for satellite MIMO transmission. Because the channels between multiple satellites and the terminal have good spatial isolation, the conditions for implementing MIMO transmission technology are met.

[0078] For example, in traditional satellite mobile communications, the single-beam-serves-single-user model limits the potential for increased transmission rates. MIMO technology, which can deliver higher rates in terrestrial networks, is hampered by the characteristics of satellite channels in satellite mobile communications. However, if multiple satellites and multiple beams serve the same user, the good spatial isolation makes it possible to achieve satellite MIMO transmission, thereby providing users with higher-speed services.

[0079] This application focuses on providing high-speed data transmission services to users after they have established access with the satellite. The primary satellite operates in an on-board processing mode, meaning the base station is located on the satellite, while the secondary satellites use a transparent forwarding mode, solely responsible for signal forwarding. The primary and secondary satellites together form a satellite cluster, providing services to individual terminals simultaneously, as follows: Figure 1 The diagram shown is a schematic representation of a working mode in which the primary satellite and secondary satellites simultaneously provide services to a single terminal, according to an embodiment of this application. Figure 1 The link between the gateway station and the main satellite is a feeder link, and the direct transmission link between the main satellite and the terminal is... Figure 1 User link 1, also known as the second link in the following embodiments, is a transmission link between the primary satellite and the terminal via transparent forwarding through a secondary satellite. Figure 1 User link 2 in the above example is the first link in the following embodiment.

[0080] It should be noted that Figure 1 Only one auxiliary satellite is shown in the illustration. In practice, this application embodiment also applies to situations where there is one main satellite and multiple auxiliary satellites forming a satellite cluster, providing services to a single terminal. That is to say, the number of auxiliary satellites in this application embodiment can be one or more.

[0081] The primary satellite communicates with the terminal via direct transmission, while the secondary satellite transmits one signal from the primary satellite to the terminal through transparent forwarding. In this scenario, the secondary satellite's operation is similar to traditional transparent forwarding, except that the original ground base station is replaced by a satellite-based base station. At this point, the multiple satellites have good spatial isolation relative to the terminal's channels, thus enabling the implementation of MIMO transmission technology.

[0082] For example, in a communication scenario, the primary satellite acts as the core, directly interacting with the terminal; while the secondary satellite acts as a faithful relay, accurately forwarding the primary satellite's signals to the terminal. This collaborative approach, coupled with good channel spatial isolation, makes the application of MIMO transmission technology possible, potentially bringing users a more efficient and faster data transmission experience.

[0083] In this embodiment, the aforementioned main satellite is the satellite that undertakes the main communication processing tasks, adopting an on-board processing working mode. The base station is located on this satellite; that is, an onboard base station is installed on the main satellite. It communicates directly with the terminal, playing a core role in data transmission and processing, similar to the main control and transmission node in a communication system.

[0084] The main satellite can operate in regeneration mode. In regeneration mode, the main satellite can regenerate or reconstruct the input information during data transmission, signal processing, or system operation. It does not simply transmit the original input, but processes and modifies the input through specific algorithms, rules, or processing methods to produce new outputs.

[0085] For example, the master satellite may be responsible for the main processing and response to requests sent by the terminal, and for determining the method and content of data transmission.

[0086] In this embodiment, the auxiliary satellite primarily undertakes the task of signal relay, employing a transparent relay mode, also known as a pass-through mode. In this mode, the auxiliary satellite does not perform complex processing; it simply transmits one signal from the main satellite to the terminal. The operating mode is similar to traditional transparent relay, but the base station changes from a ground-based station to a satellite-borne base station installed on the main satellite.

[0087] For example, auxiliary satellites act as auxiliary channels in communications, increasing the path and reliability of signal transmission.

[0088] In this embodiment, the terminal is the device that ultimately receives and uses satellite data transmission services, which may be a mobile phone, computer, or other specific communication device.

[0089] For example, communication terminals on mobile vehicles within satellite communication coverage areas, or fixed communication sites in remote areas.

[0090] In this embodiment, the main satellite, auxiliary satellite, and terminal together constitute a satellite communication system, which achieves high-speed data transmission service through their respective functions and cooperation.

[0091] The multiplexing method in this application embodiment may include a multiplexing method for downlink transmission and a multiplexing method for uplink transmission. These two multiplexing methods will be described below.

[0092] (1) Multiplexing method for downlink transmission.

[0093] like Figure 2 The diagram shown is a flowchart illustrating a multiplexing method for downlink transmission according to an embodiment of this application. The method includes, but is not limited to, the following steps:

[0094] 201. The terminal sends the downlink synchronization time difference to the main satellite.

[0095] The downlink synchronization time difference is the arrival time difference between downlink signals transmitted via the second link and those transmitted via the first link. The first link is a transmission link between the primary satellite and the terminal that uses a secondary satellite for transparent forwarding, while the second link is a direct transmission link between the primary satellite and the terminal.

[0096] Correspondingly, the master satellite can obtain the downlink synchronization time difference, that is, the master satellite can receive the downlink synchronization time difference sent by the terminal.

[0097] The main satellite is equipped with an onboard base station. In this embodiment, the main satellite execution steps can be performed by the onboard base station on the main satellite.

[0098] 202. The main satellite sends the first downlink signal to the terminal through the first link at the first moment.

[0099] 203. The main satellite sends a second downlink signal to the terminal via the second link at the second time.

[0100] In this embodiment of the application, the main satellite can send a first downlink signal to the terminal through a first link at a first moment based on the downlink synchronization time difference, and send a second downlink signal to the terminal through a second link at a second moment.

[0101] The time difference between the first moment and the second moment is the downlink synchronization time difference.

[0102] 204. The terminal receives the first downlink signal transmitted by the main satellite through the first link at the first moment and the second downlink signal transmitted through the second link at the second moment at the first target time domain location.

[0103] In this embodiment of the application, since the downlink synchronization time difference is taken into account, the first downlink signal and the second downlink signal can be received simultaneously at the first target time domain location.

[0104] The aforementioned multiplexing method involves two links. The first link is a purely passive link between the primary satellite and the terminal, transparently relayed via a secondary satellite. The second link is a direct transmission link between the primary satellite and the terminal. Since the primary satellite can obtain the downlink synchronization time difference between sending downlink signals to the terminal via the second link and via the first link, it can send the first downlink signal via the first link at the first moment, with the downlink synchronization time difference preceding the second moment. Conversely, it can send the second downlink signal via the second link at the second moment. This allows the downlink signals sent by the primary satellite via two different links to arrive at the terminal simultaneously. This combination of regenerative and transparent transmission modes provides users with channel conditions for multi-stream transmission, enabling users to receive multi-stream data through multi-satellite collaborative transmission after access, thereby improving the user's data transmission rate.

[0105] Time and frequency synchronization between the master satellite and the terminal includes two parts: ephemeris calculation and signal measurement. The system operates in a mode similar to terrestrial MIMO transmission technology. However, due to the high mobility of satellite mobile communication scenarios, pre-compensation based on ephemeris information is required during time and frequency synchronization.

[0106] In some embodiments, the master satellite sends a first synchronization signal to the terminal via a first link and a second synchronization signal to the terminal via a second link; wherein the first synchronization signal and the second synchronization signal are used to perform downlink synchronization measurements to determine the downlink synchronization time difference.

[0107] Correspondingly, the terminal can receive the first synchronization signal sent by the main satellite through the first link, and the second synchronization signal sent through the second link.

[0108] After acquiring the first synchronization signal and the second synchronization signal, the terminal can acquire the first time-frequency pre-compensation information of the first link and the second time-frequency pre-compensation information of the second link; then, it performs time-frequency pre-compensation on the first synchronization signal based on the first time-frequency pre-compensation information to determine the first downlink compensation signal; it performs time-frequency pre-compensation on the second synchronization signal based on the second time-frequency pre-compensation information to determine the second downlink compensation signal; and it performs downlink synchronization measurement on the first downlink compensation signal and the second downlink compensation signal to determine the downlink synchronization time difference.

[0109] In some embodiments, the first time-frequency pre-compensation information includes: a first time offset pre-compensation value and a first frequency offset pre-compensation value. The acquisition of the first time-frequency pre-compensation information for the first link may include, but is not limited to:

[0110] First, based on the ephemeris information of the primary satellite and the secondary satellite, determine the position and speed of the primary satellite, as well as the position and speed of the secondary satellite.

[0111] Then, based on the positions of the primary satellite and the secondary satellite, the first timing pre-compensation value is determined; based on the positions of the secondary satellite and the terminal, the second timing pre-compensation value is determined; and based on the first and second timing pre-compensation values, the first time offset pre-compensation value is determined. The first time offset pre-compensation value can be obtained by superimposing the first and second timing pre-compensation values.

[0112] Secondly, the first frequency offset pre-compensation value can be determined based on the movement speed of the primary satellite and the secondary satellite; the second frequency offset pre-compensation value can be determined based on the movement speed of the secondary satellite and the terminal. The first frequency offset pre-compensation value is then determined based on the first and second frequency offset pre-compensation values. The first frequency offset pre-compensation value can be obtained by superimposing the first and second frequency offset pre-compensation values.

[0113] In some embodiments, the ephemeris information includes position and speed, so the position and speed can be obtained directly from the ephemeris information.

[0114] In some embodiments, the ephemeris information includes orbital parameters and related correction parameters for the orbital parameters, and the position and speed of movement can be calculated based on the orbital parameters and related correction parameters.

[0115] In some embodiments, the second time-frequency pre-compensation information includes: a second time offset pre-compensation value and a second frequency offset pre-compensation value. The acquisition of the second time-frequency pre-compensation information of the second link may include, but is not limited to: determining the position and moving speed of the main satellite based on the ephemeris information of the main satellite; determining the second time offset pre-compensation value based on the position of the main satellite and the position of the terminal; and determining the second frequency offset pre-compensation value based on the moving speed of the main satellite and the moving speed of the terminal.

[0116] In satellite communication, the changing positions and relative motion of the primary satellite, secondary satellites, and terminals can cause time and frequency offsets in signal transmission. To compensate for these potential deviations and ensure the accuracy and stability of communication, corresponding pre-compensation values ​​need to be calculated based on their positions and movement speeds.

[0117] For example, if the distance between the primary satellite, the secondary satellite, and the terminal is constantly changing, the time it takes for the signal to arrive at the terminal will deviate. This time deviation can be estimated and compensated for using their positions; this is the process of determining the second time offset pre-compensation value. Similarly, if the primary satellite, the secondary satellite, and the terminal move at different speeds, the signal frequency will change. The frequency deviation that needs to be compensated can be calculated using their moving speeds.

[0118] The purpose of the above series of operations is to achieve more accurate downlink signal synchronization between the master satellite and the terminal, thereby preparing for subsequent high-speed multi-channel data transmission services.

[0119] Based on the aforementioned pre-compensation, time-frequency synchronization is then performed based on signal measurement. Signal measurement corresponds to the downlink synchronization signal (SSB), with the smallest measurement granularity being the time-domain sampling point. For the downlink scenario, the arrival time of the SSB from the primary satellite is tDL1, and the arrival time of the SSB relayed via the secondary satellite is tDL2. Therefore, the downlink timing offset between the two streams is tDL2 - tDL1. This means that the user link relayed via the secondary satellite needs to advance the timing by tDL2 - tDL1 when sending downlink data to ensure that the multi-stream signals are aligned upon arrival at the terminal.

[0120] (2) Multiplexing method for uplink transmission.

[0121] like Figure 3 The diagram shown is a flowchart illustrating a multiplexing method for uplink transmission according to an embodiment of this application. The method includes, but is not limited to, the following steps:

[0122] 301. The main satellite sends the uplink synchronization time difference to the terminal.

[0123] The uplink synchronization time difference is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; the first link is a transmission link between the main satellite and the terminal that is transparently forwarded by the auxiliary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0124] 302. At the third moment, the terminal sends the first uplink signal to the main satellite through the first link.

[0125] 303. At the fourth moment, the terminal sends the second uplink signal to the main satellite via the second link.

[0126] Based on the uplink synchronization time difference, the terminal can send the first uplink signal to the main satellite via the first link at the third time, and send the second uplink signal to the main satellite via the second link at the fourth time.

[0127] 304. The main satellite receives the first uplink signal transmitted by the terminal at the second target time domain location via the first link through transparent relay by the auxiliary satellite at the third time, and the second uplink signal transmitted directly via the second link at the fourth time.

[0128] The advance time between the third and fourth moments is the uplink synchronization time difference.

[0129] In this embodiment of the application, since the uplink synchronization time difference is taken into account, the first uplink signal and the second uplink signal can be received simultaneously at the second target time domain location.

[0130] The aforementioned multiplexing method involves two links. The first link is a purely passive link between the primary satellite and the terminal, transparently relayed via a secondary satellite. The second link is a direct transmission link between the primary satellite and the terminal. Since the terminal can obtain the uplink synchronization time difference between sending uplink signals to the satellite via the second link and via the first link, it can send the first uplink signal via the first link at a third time, which is the uplink synchronization time difference prior to the second time. Conversely, it can send the second uplink signal via the second link at the second time. This allows the uplink signals sent by the terminal via two different links to reach the primary satellite simultaneously. This provides multi-stream transmission channel conditions through a combination of regenerative and transparent transmission modes, enabling users to receive multi-stream data transmission from a single user through multi-satellite collaborative transmission after access, thereby improving the user's data transmission rate.

[0131] In some embodiments of this application, the main satellite can receive a first uplink compensation signal sent by the terminal through a first link and a second uplink compensation signal sent through a second link; and perform uplink synchronization measurement on the first uplink compensation signal and the second uplink compensation signal to determine the uplink synchronization time difference.

[0132] In some embodiments of this application, the terminal can obtain third time-frequency pre-compensation information of the first link and fourth time-frequency pre-compensation information of the second link; perform time-frequency pre-compensation on the first synchronization signal according to the third time-frequency pre-compensation information to determine the first compensated signal; perform time-frequency pre-compensation on the second synchronization signal according to the fourth time-frequency pre-compensation information to determine the compensated second uplink compensated signal; send the first uplink compensated signal to the main satellite through the first link, and send the second uplink compensated signal to the main satellite through the second link.

[0133] The synchronization signal mentioned above is the uplink synchronization signal.

[0134] Among them, the first uplink compensation signal and the second uplink compensation signal are used to perform uplink synchronization measurement to determine the uplink synchronization time difference.

[0135] In some embodiments, the third time-frequency pre-compensation information includes: a third time offset pre-compensation value and a third frequency offset pre-compensation value. Obtaining the third time-frequency pre-compensation information between the auxiliary satellite and the terminal may include, but is not limited to:

[0136] First, based on the ephemeris information of the main satellite and the auxiliary satellite, determine the position and speed of the main satellite, as well as the position and speed of the auxiliary satellite.

[0137] Then, based on the positions of the primary satellite and the secondary satellite, the first timing pre-compensation value is determined; based on the positions of the secondary satellite and the terminal, the second timing pre-compensation value is determined; based on the first and second timing pre-compensation values, the third timing offset pre-compensation value is determined.

[0138] Secondly, based on the moving speed of the main satellite and the moving speed of the auxiliary satellite, the first frequency offset pre-compensation value is determined; based on the moving speed of the auxiliary satellite and the moving speed of the terminal, the second frequency offset pre-compensation value is determined; based on the first and second frequency offset pre-compensation values, the third frequency offset pre-compensation value is determined.

[0139] In some embodiments, the fourth time-frequency pre-compensation information includes: a fourth time offset pre-compensation value and a fourth frequency offset pre-compensation value. Obtaining the second time-frequency pre-compensation information between the master satellite and the terminal may include, but is not limited to: determining the position and moving speed of the master satellite based on the ephemeris information of the master satellite; determining the fourth time offset pre-compensation value based on the position of the master satellite and the position of the terminal; and determining the fourth frequency offset pre-compensation value based on the moving speed of the master satellite and the moving speed of the terminal.

[0140] In satellite communication, the changing positions and relative motion of the primary satellite, secondary satellites, and terminals can cause time and frequency offsets in signal transmission. To compensate for these potential deviations and ensure the accuracy and stability of communication, corresponding pre-compensation values ​​need to be calculated based on their positions and movement speeds.

[0141] For example, if the distance between the primary satellite, the secondary satellite, and the terminal is constantly changing, the time it takes for the signal to arrive at the terminal will deviate. This time deviation can be estimated and compensated for using their positions; this is the process of determining the second time offset pre-compensation value. Similarly, if the primary satellite, the secondary satellite, and the terminal move at different speeds, the signal frequency will change. The frequency deviation that needs to be compensated can be calculated using their moving speeds.

[0142] The purpose of the above series of operations is to achieve more accurate uplink signal synchronization between the master satellite and the terminal.

[0143] Based on the aforementioned pre-compensation, time-frequency synchronization is then performed based on signal measurements. Signal measurements correspond to the uplink synchronization signal, and downlink to the preamble. The smallest granularity of measurement is the time-domain sampling point. For the uplink scenario, the primary satellite detects that the arrival time of the preamble sent by the terminal is tUL1, and the arrival time of the preamble relayed by the secondary satellite is tUL2. Therefore, the downlink timing offset between the two streams is tUL2 - tUL1. This means that the user link relayed by the secondary satellite needs to advance the timing by tUL2 - tUL1 when sending uplink data to ensure that the multi-stream signals are aligned when they arrive at the primary satellite's base station.

[0144] In this embodiment of the application, different MIMO transmission processes may be performed based on the different capabilities of the terminal antenna.

[0145] In one embodiment, the terminal antenna is an omnidirectional antenna without beamforming capability. The terminal then reports channel state information to the main satellite and selects a suitable precoding codebook. The main satellite's base station and the terminal implement the aforementioned multiplexing method via the first and second links according to the selected precoding codebook.

[0146] If the terminal antenna is an omnidirectional antenna without beamforming capability, it means that the terminal antenna transmits and receives signals uniformly in all directions, and cannot specifically adjust the signal beam. In this case, the terminal reports channel status information to the master satellite, that is, informs the master satellite of the current communication channel status, and then selects an appropriate precoding codebook. Afterwards, the master satellite base station and the terminal implement the aforementioned multiplexing method through the first and second links, according to the selected precoding codebook.

[0147] In one embodiment, if the terminal antenna has beamforming capability, the terminal adjusts the beam direction according to ephemeris information and achieves the above-mentioned multiplexing method with the base station of the main satellite through the first and second links via spatial isolation.

[0148] If the terminal antenna has shaping capability, it means that the terminal antenna can adjust the direction and shape of the signal beam.

[0149] The multi-channel transmission method provided in this application, compared with the mechanism of single-beam and single-user data transmission, introduces a multi-satellite MIMO transmission scheme, which enables users to achieve multi-stream data transmission with multiple satellites, thereby effectively improving the data transmission rate.

[0150] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0151] Based on the same technical concept, this application provides a schematic diagram of a communication device. This communication device can realize the functions of the main satellite or terminal in the aforementioned embodiments.

[0152] For example, Figure 4 This is a schematic diagram of a communication device according to one embodiment. The communication device includes: a memory 401, a transceiver 402, and a processor 403, wherein the memory 401, transceiver 402, and processor 403 are connected via a bus interface.

[0153] The memory 401 is used to store computer programs; the transceiver 402 is used to send and receive data under the control of the processor 403.

[0154] For downlink transmission, in the case of a main satellite with an onboard base station: the processor 403 described above is used to read the computer program in the memory 401 and perform the following operations:

[0155] The downlink synchronization time difference is obtained, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal.

[0156] Based on the downlink synchronization time difference, a first downlink signal is sent to the terminal through the first link at a first moment, and a second downlink signal is sent to the terminal through the second link at a second moment;

[0157] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0158] In some embodiments, the processor 403 described above is further configured to read the computer program in the memory 401 and perform the following operations:

[0159] A first synchronization signal is sent to the terminal via the first link, and a second synchronization signal is sent to the terminal via the second link;

[0160] The first synchronization signal and the second synchronization signal are used to perform downlink synchronization measurement to determine the downlink synchronization time difference.

[0161] For downlink transmission, in the case where the communication device is a terminal: the processor 403 described above is used to read the computer program in the memory 401 and perform the following operations:

[0162] The downlink synchronization time difference is sent to the main satellite. The downlink synchronization time difference is the arrival time difference between the downlink signal sent through the second link and the downlink signal sent through the first link. The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal.

[0163] At the first target time domain location, the first downlink signal transmitted by the main satellite through the first link at the first moment, and the second downlink signal transmitted through the second link at the second moment;

[0164] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0165] In some embodiments, the processor 403 described above is further configured to read the computer program in the memory 401 and perform the following operations:

[0166] Receive the first synchronization signal sent by the main satellite through the first link, and the second synchronization signal sent through the second link;

[0167] Obtain the first time-frequency pre-compensation information of the first link and the second time-frequency pre-compensation information of the second link;

[0168] The first synchronization signal is pre-compensated based on the first time-frequency pre-compensation information to determine the first downlink compensation signal.

[0169] The second synchronization signal is pre-compensated based on the second time-frequency pre-compensation information to determine the second downlink compensation signal.

[0170] Downlink synchronization measurements are performed on the first downlink compensation signal and the second downlink compensation signal to determine the downlink synchronization time difference.

[0171] In some embodiments, the first time-frequency pre-compensation information includes: a first time offset pre-compensation value and a first frequency offset pre-compensation value. The processor 403 described above is specifically used to read the computer program in the memory 401 and perform the following operations:

[0172] Based on the ephemeris information of the primary satellite and the ephemeris information of the secondary satellite, the position and speed of the primary satellite and the position and speed of the secondary satellite are determined.

[0173] The first segment of timing pre-compensation value is determined based on the positions of the primary satellite and the secondary satellite;

[0174] The second segment timing pre-compensation value is determined based on the position of the auxiliary satellite and the position of the terminal;

[0175] The first time offset pre-compensation value is determined based on the first segment timing pre-compensation value and the second segment timing pre-compensation value;

[0176] The first segment frequency offset pre-compensation value is determined based on the moving speed of the main satellite and the moving speed of the auxiliary satellite.

[0177] The second frequency offset pre-compensation value is determined based on the moving speed of the auxiliary satellite and the moving speed of the terminal.

[0178] The first frequency offset pre-compensation value is determined based on the first segment frequency offset pre-compensation value and the second segment frequency offset pre-compensation value.

[0179] In some embodiments, the second time-frequency pre-compensation information includes: a second time offset pre-compensation value and a second frequency offset pre-compensation value. The processor 403 is specifically configured to read the computer program in the memory 401 and perform the following operations:

[0180] Based on the ephemeris information of the main satellite, determine the position and speed of movement of the main satellite;

[0181] The second time offset pre-compensation value is determined based on the position of the main satellite and the position of the terminal;

[0182] The second frequency offset pre-compensation value is determined based on the moving speed of the main satellite and the moving speed of the terminal.

[0183] For uplink transmission, when the communication device is a terminal: the processor 403 described above is used to read the computer program in the memory 401 and perform the following operations:

[0184] The uplink synchronization time difference is obtained, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; the first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0185] Based on the uplink synchronization time difference, a first uplink signal is sent to the main satellite through the first link at the third time, and a second uplink signal is sent to the main satellite through the second link at the fourth time;

[0186] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0187] For uplink transmission, where the communication device is a main satellite and the main satellite has an onboard base station: the processor 403 described above is used to read the computer program in the memory 401 and perform the following operations:

[0188] The uplink synchronization time difference is sent to the terminal. The uplink synchronization time difference is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal.

[0189] At the second target time domain location, the terminal receives the first uplink signal transmitted by the terminal at the third time through the first link of the auxiliary satellite transparent relay, and the second uplink signal transmitted directly through the second link at the fourth time.

[0190] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0191] In one exemplary embodiment, such as Figure 5 As shown, a structural block diagram of a main satellite is provided. The main satellite is equipped with an onboard base station and includes:

[0192] The acquisition module 501 is used to acquire the downlink synchronization time difference value, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal.

[0193] The transmitting module 502 is used to transmit a first downlink signal to the terminal through the first link at a first moment based on the downlink synchronization time difference, and to transmit a second downlink signal to the terminal through the second link at a second moment.

[0194] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0195] In some embodiments, the sending module 502 is further configured to:

[0196] A first synchronization signal is sent to the terminal via the first link, and a second synchronization signal is sent to the terminal via the second link;

[0197] The first synchronization signal and the second synchronization signal are used to perform downlink synchronization measurement to determine the downlink synchronization time difference.

[0198] In one exemplary embodiment, such as Figure 6 As shown, a structural block diagram of a terminal is provided, including:

[0199] The transmitting module 601 is used to transmit a downlink synchronization time difference value to the main satellite. The downlink synchronization time difference value is the arrival time difference between the downlink signal transmitted through the second link and the downlink signal transmitted through the first link. The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0200] The receiving module 602 is used to receive, at the first target time domain location, a first downlink signal transmitted by the main satellite through the first link at a first moment, and a second downlink signal transmitted through the second link at a second moment;

[0201] Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

[0202] In some embodiments, the receiving module 602 is further configured to receive a first synchronization signal transmitted by the main satellite through the first link, and a second synchronization signal transmitted through the second link;

[0203] The determining module 603 is used to acquire first time-frequency pre-compensation information of the first link and second time-frequency pre-compensation information of the second link; perform time-frequency pre-compensation on the first synchronization signal according to the first time-frequency pre-compensation information to determine the first downlink compensation signal; perform time-frequency pre-compensation on the second synchronization signal according to the second time-frequency pre-compensation information to determine the second downlink compensation signal; and perform downlink synchronization measurement on the first downlink compensation signal and the second downlink compensation signal to determine the downlink synchronization time difference.

[0204] In some embodiments, the first time-frequency pre-compensation information includes: a first time offset pre-compensation value and a first frequency offset pre-compensation value. The determining module 603 is specifically configured to: determine the position and moving speed of the main satellite and the position and moving speed of the auxiliary satellite based on the ephemeris information of the main satellite and the ephemeris information of the auxiliary satellite; determine a first segment of timing pre-compensation value based on the position of the main satellite and the position of the auxiliary satellite; determine a second segment of timing pre-compensation value based on the position of the auxiliary satellite and the position of the terminal; determine the first time offset pre-compensation value based on the first segment of timing pre-compensation value and the second segment of timing pre-compensation value; determine a first segment of frequency offset pre-compensation value based on the moving speed of the main satellite and the moving speed of the auxiliary satellite; determine a second segment of frequency offset pre-compensation value based on the moving speed of the auxiliary satellite and the moving speed of the terminal; and determine the first frequency offset pre-compensation value based on the first segment of frequency offset pre-compensation value and the second segment of frequency offset pre-compensation value.

[0205] In some embodiments, the second time-frequency pre-compensation information includes: a second time offset pre-compensation value and a second frequency offset pre-compensation value, and the determining module 603 is specifically used for:

[0206] Based on the ephemeris information of the main satellite, determine the position and speed of movement of the main satellite;

[0207] The second time offset pre-compensation value is determined based on the position of the main satellite and the position of the terminal;

[0208] The second frequency offset pre-compensation value is determined based on the moving speed of the main satellite and the moving speed of the terminal.

[0209] In one exemplary embodiment, such as Figure 7 As shown, another terminal structure block diagram is provided, including:

[0210] The acquisition module 701 is used to acquire the uplink synchronization time difference value, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; the first link is a transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0211] The transmitting module 702 is used to transmit a first uplink signal to the main satellite through the first link at a third time based on the uplink synchronization time difference, and to transmit a second uplink signal to the main satellite through the second link at a fourth time;

[0212] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0213] In one exemplary embodiment, such as Figure 8 As shown, another structural block diagram of a main satellite is provided, which is equipped with an onboard base station. This main satellite includes:

[0214] The transmitting module 801 is used to send an uplink synchronization time difference value to the terminal. The uplink synchronization time difference value is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal.

[0215] The receiving module 802 is configured to receive, at a second target time domain location, a first uplink signal transmitted by the terminal through the first link at a third time, and a second uplink signal transmitted through the second link at a fourth time;

[0216] Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

[0217] It should be noted that the module division in the embodiments of this application is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0218] If the integrated modules described above are implemented as software functional modules and sold or used as independent products, they can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application.

[0219] It should be noted that the apparatus provided in this embodiment of the invention can implement all the method steps implemented in the above method embodiment and can achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0220] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements all the method steps implemented in the above method embodiments.

[0221] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements all the method steps implemented in the above method embodiments.

[0222] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0223] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0224] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A multiplexing method, characterized in that, Applied to a main satellite, on which an onboard base station is installed, the method includes: The downlink synchronization time difference is obtained, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal. Based on the downlink synchronization time difference, a first downlink signal is sent to the terminal through the first link at a first moment, and a second downlink signal is sent to the terminal through the second link at a second moment; Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

2. The method according to claim 1, characterized in that, The method further includes: A first synchronization signal is sent to the terminal via the first link, and a second synchronization signal is sent to the terminal via the second link; The first synchronization signal and the second synchronization signal are used to perform downlink synchronization measurement to determine the downlink synchronization time difference.

3. A multiplexing method, characterized in that, Applied to a terminal, the method includes: The downlink synchronization time difference is sent to the main satellite. The downlink synchronization time difference is the arrival time difference between the downlink signal sent through the second link and the downlink signal sent through the first link. The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal. At the first target time domain location, the first downlink signal transmitted by the main satellite through the first link at the first moment, and the second downlink signal transmitted through the second link at the second moment; Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

4. The method according to claim 3, characterized in that, The method further includes: Receive the first synchronization signal sent by the main satellite through the first link, and the second synchronization signal sent through the second link; Obtain the first time-frequency pre-compensation information of the first link and the second time-frequency pre-compensation information of the second link; The first synchronization signal is pre-compensated based on the first time-frequency pre-compensation information to determine the first downlink compensation signal. The second synchronization signal is pre-compensated based on the second time-frequency pre-compensation information to determine the second downlink compensation signal. Downlink synchronization measurements are performed on the first downlink compensation signal and the second downlink compensation signal to determine the downlink synchronization time difference.

5. The method according to claim 4, characterized in that, The first time-frequency pre-compensation information includes: a first time offset pre-compensation value and a first frequency offset pre-compensation value. Obtaining the first time-frequency pre-compensation information of the first link includes: Based on the ephemeris information of the primary satellite and the ephemeris information of the secondary satellite, the position and speed of the primary satellite and the position and speed of the secondary satellite are determined. The first segment of timing pre-compensation value is determined based on the positions of the primary satellite and the secondary satellite; The second segment timing pre-compensation value is determined based on the position of the auxiliary satellite and the position of the terminal; The first time offset pre-compensation value is determined based on the first segment timing pre-compensation value and the second segment timing pre-compensation value; The first frequency offset pre-compensation value is determined based on the moving speed of the main satellite and the moving speed of the auxiliary satellite. The second segment frequency offset pre-compensation value is determined based on the moving speed of the auxiliary satellite and the moving speed of the terminal; The first frequency offset pre-compensation value is determined based on the first segment frequency offset pre-compensation value and the second segment frequency offset pre-compensation value.

6. The method according to claim 4, characterized in that, The second time-frequency pre-compensation information includes: a second time offset pre-compensation value and a second frequency offset pre-compensation value. Obtaining the second time-frequency pre-compensation information of the second link includes: Based on the ephemeris information of the main satellite, determine the position and speed of movement of the main satellite; The second time offset pre-compensation value is determined based on the position of the main satellite and the position of the terminal; The second frequency offset pre-compensation value is determined based on the moving speed of the main satellite and the moving speed of the terminal.

7. A multiplexing method, characterized in that, Applied to a terminal, the method includes: The uplink synchronization time difference is obtained, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; the first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal. Based on the uplink synchronization time difference, a first uplink signal is sent to the main satellite through the first link at the third time, and a second uplink signal is sent to the main satellite through the second link at the fourth time; Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

8. A multiplexing method, characterized in that, Applied to a main satellite, on which an onboard base station is installed, the method includes: The uplink synchronization time difference is sent to the terminal. The uplink synchronization time difference is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal. At the second target time domain location, the terminal receives the first uplink signal transmitted by the terminal at the third time through the first link of the auxiliary satellite transparent relay, and the second uplink signal transmitted directly through the second link at the fourth time. Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

9. A main satellite, characterized in that, The main satellite is equipped with an onboard base station, including: a memory, a transceiver, and a processor. The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: The downlink synchronization time difference is obtained, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal. Based on the downlink synchronization time difference, a first downlink signal is sent to the terminal through the first link at a first moment, and a second downlink signal is sent to the terminal through the second link at a second moment; Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

10. The main satellite according to claim 9, characterized in that, The processor is also configured to read the computer program in the memory and perform the following operations: A first synchronization signal is sent to the terminal via the first link, and a second synchronization signal is sent to the terminal via the second link; The first synchronization signal and the second synchronization signal are used to perform downlink synchronization measurement to determine the downlink synchronization time difference.

11. A terminal, characterized in that, include: Memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: Send downlink synchronization time difference to the main satellite, wherein the downlink synchronization time difference is the arrival time difference between the downlink signal sent via the second link and the downlink signal sent via the first link; The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal. At the first target time domain location, the first downlink signal transmitted by the main satellite through the first link at the first moment, and the second downlink signal transmitted through the second link at the second moment; Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

12. The terminal according to claim 11, characterized in that, The processor is also configured to read the computer program in the memory and perform the following operations: Receives a first synchronization signal sent by the main satellite through the first link, and receives a second synchronization signal sent through the second link; Obtain the first time-frequency pre-compensation information of the first link and the second time-frequency pre-compensation information of the second link; The first synchronization signal is pre-compensated based on the first time-frequency pre-compensation information to determine the first downlink compensation signal. The second synchronization signal is pre-compensated based on the second time-frequency pre-compensation information to determine the second downlink compensation signal. Downlink synchronization measurements are performed on the first downlink compensation signal and the second downlink compensation signal to determine the downlink synchronization time difference.

13. The terminal according to claim 12, characterized in that, The first time-frequency pre-compensation information includes: a first time offset pre-compensation value and a first frequency offset pre-compensation value. The processor is specifically configured to read the computer program in the memory and perform the following operations: Based on the ephemeris information of the primary satellite and the ephemeris information of the secondary satellite, the position and speed of the primary satellite and the position and speed of the secondary satellite are determined. The first segment of timing pre-compensation value is determined based on the positions of the primary satellite and the secondary satellite; The second segment timing pre-compensation value is determined based on the position of the auxiliary satellite and the position of the terminal; The first time offset pre-compensation value is determined based on the first segment timing pre-compensation value and the second segment timing pre-compensation value; The first frequency offset pre-compensation value is determined based on the moving speed of the main satellite and the moving speed of the auxiliary satellite. The second segment frequency offset pre-compensation value is determined based on the moving speed of the auxiliary satellite and the moving speed of the terminal; The first frequency offset pre-compensation value is determined based on the first segment frequency offset pre-compensation value and the second segment frequency offset pre-compensation value.

14. The terminal according to claim 12, characterized in that, The second time-frequency pre-compensation information includes: a second time offset pre-compensation value and a second frequency offset pre-compensation value. Specifically, the processor is used to read the computer program in the memory and perform the following operations: Based on the ephemeris information of the main satellite, determine the position and speed of movement of the main satellite; The second time offset pre-compensation value is determined based on the position of the main satellite and the position of the terminal; The second frequency offset pre-compensation value is determined based on the moving speed of the main satellite and the moving speed of the terminal.

15. A terminal, characterized in that, include: Memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: The uplink synchronization time difference is obtained, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; The first link is a transmission link between the primary satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the primary satellite and the terminal. Based on the uplink synchronization time difference, a first uplink signal is sent to the main satellite through the first link at the third time, and a second uplink signal is sent to the main satellite through the second link at the fourth time; Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

16. A main satellite, characterized in that, The main satellite is equipped with an onboard base station, including: a memory, a transceiver, and a processor. The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and perform the following operations: The uplink synchronization time difference is sent to the terminal. The uplink synchronization time difference is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite. The second link is a direct transmission link between the main satellite and the terminal. At the second target time domain location, the terminal receives a first uplink signal transmitted through the first link at a third time and a second uplink signal transmitted through the second link at a fourth time. Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

17. A main satellite, characterized in that, The main satellite is equipped with an onboard base station, including: The acquisition module is used to acquire the downlink synchronization time difference value, which is the arrival time difference between sending downlink signals to the terminal via the second link and via the first link; the first link is the transmission link between the main satellite and the terminal via transparent forwarding through the auxiliary satellite, and the second link is the direct transmission link between the main satellite and the terminal; The transmitting module is configured to transmit a first downlink signal to the terminal via the first link at a first moment based on the downlink synchronization time difference, and to transmit a second downlink signal to the terminal via the second link at a second moment; Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

18. A terminal, characterized in that, include: The transmitting module is used to transmit a downlink synchronization time difference to the main satellite, wherein the downlink synchronization time difference is the arrival time difference between transmitting downlink signals via the second link and transmitting them via the first link; The first link is a transmission link between the main satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal. The receiving module is configured to receive, at the first target time domain location, a first downlink signal transmitted by the main satellite through the first link at a first moment, and a second downlink signal transmitted through the second link at a second moment; Wherein, the advance time of the first moment relative to the second moment is the downlink synchronization time difference.

19. A terminal, characterized in that, include: The acquisition module is used to acquire the uplink synchronization time difference, which is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link; The first link is a transmission link between the primary satellite and the terminal via transparent forwarding through a secondary satellite, and the second link is a direct transmission link between the primary satellite and the terminal. The transmitting module is configured to transmit a first uplink signal to the main satellite via the first link at a third time based on the uplink synchronization time difference, and to transmit a second uplink signal to the main satellite via the second link at a fourth time; Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

20. A main satellite, characterized in that, The main satellite is equipped with an onboard base station, including: a memory, a transceiver, and a processor. The transmitting module is used to send an uplink synchronization time difference value to the terminal. The uplink synchronization time difference value is the arrival time difference between sending uplink signals to the main satellite via the second link and via the first link. The first link is a transmission link between the main satellite and the terminal that is transparently forwarded via a secondary satellite, and the second link is a direct transmission link between the main satellite and the terminal. The receiving module is configured to receive, at a second target time domain location, a first uplink signal transmitted by the terminal through the first link at a third time, and a second uplink signal transmitted through the second link at a fourth time; Wherein, the advance time of the third moment relative to the fourth moment is the uplink synchronization time difference.

21. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method according to any one of claims 1 to 8.

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