Satellite communication method and system based on store-and-forward (S&F) operations

Abstract

The application discloses a satellite communication method and system based on store-and-forward (S&F) operation, and the method comprises the following steps: receiving, by a high-orbit satellite, a mobile trajectory of a mobile terminal uploaded by a low-orbit satellite, and receiving position information of a ground gateway station and ephemeris information of a related low-orbit satellite uploaded by the ground gateway station; in the high-orbit satellite, calculating a feeder link connection period of each low-orbit satellite and each ground gateway station according to the ephemeris information and the position of the ground gateway station; in the high-orbit satellite, screening the low-orbit satellite based on the ephemeris information, the mobile trajectory and the feeder link connection period to generate a monitoring list used for S&F operation. The satellite communication method has the advantages that the monitoring list used for guiding the S&F operation is dynamically generated through the cooperation of the high-orbit satellite and the low-orbit satellite, the mobile terminal only listens to a paging message of a low-orbit satellite in the monitoring list, the ground gateway station directionally sends MT data, invalid listening and redundant transmission are reduced, the energy consumption of the mobile terminal is reduced, and the satellite bandwidth is saved.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and in particular to a satellite communication method and system based on store-and-forward (S&F) operations. Background Technology

[0002] Store and Forward (S&F) is a phased satellite communication mode designed specifically for latency-tolerant services. Its core processes include:

[0003] Service link phase: The terminal (UE) establishes a connection with the satellite and transmits data. At this time, the satellite is not connected to the ground network, and the data is temporarily stored on the satellite.

[0004] Feeder link phase: After the satellite establishes a connection with the ground gateway station, it forwards the cached data to the ground network.

[0005] This mode allows for the maintenance of basic communication capabilities during periods of intermittent satellite coverage or feeder link disruptions, making it suitable for non-real-time applications such as the Internet of Things and marine monitoring.

[0006] Existing satellite communication systems supporting S&F typically employ a pre-configured static monitoring list. This means that satellites broadcast a predefined static list of satellite IDs (containing identifiers of satellites supporting S&F operation) to the terminal, which then continuously listens for the broadcast signals from all satellites in the list. However, due to dynamic changes in satellite coverage (especially for low-Earth orbit satellites), the static list cannot reflect real-time link status, resulting in the terminal listening to a large number of invalid satellites and a surge in energy consumption.

[0007] Another approach involves blind listening and random access: without a monitoring list, the terminal needs to scan all available satellite frequency bands to find S&F opportunities. However, frequent RF module activation leads to excessive terminal power consumption and makes it easy to miss effective communication windows.

[0008] Alternatively, ground gateway stations can predict feeder link availability based on historical ephemeris data and send fixed-duration S&F (Satellite and Flight) operation commands to terminals. However, without considering the terminal's real-time location and dynamic satellite coverage, the prediction error is large, leading to communication recovery delays or data loss. Summary of the Invention

[0009] The purpose of this invention is to provide a satellite communication method and system based on store-and-forward (S&F) operation that can dynamically generate S&F operation parameters based on real-time data in order to overcome the shortcomings of the above-mentioned technical problems.

[0010] To achieve the above objectives, this invention provides a satellite communication method based on store-and-forward (S&F) operations for a high-Earth orbit (HEO) and low-Earth orbit (LEO) satellite networking communication system. The communication system includes HEO satellites and several LEO satellites. The LEO satellites support S&F operations, and base stations and core network elements are deployed on each LEO satellite. Inter-satellite links exist between the LEO satellites, and inter-satellite links exist between the LEO satellites and the HEO satellites. The method includes:

[0011] The high-orbit satellite receives the mobile terminal's movement trajectory uploaded by the low-orbit satellite, as well as the location information of the ground gateway station and the ephemeris information of the low-orbit satellite related to the area where the mobile terminal is currently and for a period of time in the future, uploaded by the ground gateway station.

[0012] In the high-orbit satellite, the feeder link connection period between each low-orbit satellite and each ground gateway station is calculated based on the ephemeris information and the location of the ground gateway station;

[0013] Among the high-orbit satellites, based on the ephemeris information, the movement trajectory, and the feeder link connection period, low-orbit satellites that meet one of the following conditions are selected to generate a monitoring list for S&F operations. The data items of the monitoring list include the low-orbit satellite identifier and the corresponding feeder link connection time and ground gateway identifier.

[0014] Condition 1: The service link between the mobile terminal and the mobile terminal is available within a specific future time period, and a feeder link connection can be established with at least one ground gateway station within that time period;

[0015] The monitoring list is broadcast to the mobile terminal and the ground gateway station via high-orbit satellite;

[0016] The monitoring list is used to indicate the dynamic operation of mobile terminals and ground gateways during S&F operations.

[0017] Preferably, during S&F operations, the mobile terminal only listens for paging messages from the LEO satellites in the monitoring list, and the ground gateway station only sends motion termination data through the LEO satellites in the monitoring list.

[0018] Preferably, in the high-orbit satellite, the duration of S&F operation is also generated based on the feeder link connection cycle, and the duration is broadcast to the mobile terminal and the ground gateway station.

[0019] Preferably, at the end of the duration of the S&F operation, the mobile terminal initiates a registration request to the corresponding low-Earth orbit satellite in the monitoring list, and the ground gateway station transmits MT data to the corresponding low-Earth orbit satellite to restore real-time communication.

[0020] Preferably, the method for the low-orbit satellite to acquire the movement trajectory of the mobile terminal includes:

[0021] The network data analysis function in the core network element receives the dynamic location information of the mobile terminal uploaded by the base station in real time, and the network data analysis function generates the movement trajectory based on the dynamic location information.

[0022] Preferably, the high-orbit satellite generates the monitoring list based on a deployed edge computing server.

[0023] Preferably, the high-orbit satellite and the low-orbit satellite interact through user plane functions.

[0024] The present invention also provides a satellite communication system based on store-and-forward (S&F) operation, which performs communication operations based on the satellite communication method described above.

[0025] The present invention also provides a satellite communication system, comprising:

[0026] One or more processors;

[0027] Memory;

[0028] and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the satellite communication method as described above.

[0029] The present invention also provides a computer-readable storage medium comprising a computer program that can be executed by a processor to perform the satellite communication method described above.

[0030] Compared with existing technologies, the satellite communication method provided by the present invention generates a monitoring list through joint screening based on mobile terminal trajectory, low-Earth orbit satellite ephemeris, and feeder link cycle. It selects only low-Earth orbit satellites that simultaneously meet the requirements of service link availability (covering mobile terminals) and feeder link availability (covering ground gateway stations) within a specific future time period, avoiding mobile terminals listening to invalid satellites. The ground gateway station only needs to send MT data to the satellites in the monitoring list, reducing redundant data transmission. Furthermore, the complex calculations involving multi-source data fusion are handled by high-Earth orbit satellites, alleviating the computing power bottleneck of low-Earth orbit satellites. Moreover, utilizing the wide-area coverage capability of high-Earth orbit satellites, the monitoring list is simultaneously broadcast to all mobile terminals and ground gateway stations, effectively reducing command issuance delays. Attached Figure Description

[0031] Figure 1 This is a flowchart of a satellite communication method in an embodiment of the present invention.

[0032] Figure 2 This is a signaling flowchart for obtaining the movement trajectory in an embodiment of the present invention. Detailed Implementation

[0033] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0034] This embodiment discloses a satellite communication method based on store-and-forward (S&F) operations for use in high and low orbit satellite networking communication systems.

[0035] First, it should be noted that in satellite communications, S&F operation is a communication mode specifically designed for delay-tolerant services (such as sensor data reporting and offline message push), and it includes two key phases:

[0036] Storage phase: The terminal establishes a connection with the satellite (service link) and uploads data to the satellite. At this time, the satellite is not connected to the ground network (feeder link is disconnected), and the data is temporarily stored on the satellite.

[0037] Relay phase: The satellite reconnects with the ground network (feeder link reconstruction), and the satellite forwards the stored data to the ground gateway station, which finally transmits it to the target server.

[0038] The following are typical scenarios for satellite communication using S&F operations:

[0039] IoT devices in remote areas: When the satellite temporarily leaves the coverage area of ​​the ground station, the device can still upload data to the satellite, and then forward the data after the satellite enters the coverage area of ​​the ground station.

[0040] Emergency Rescue Terminal: In disaster sites without terrestrial network coverage, the terminal sends distress messages in batches via S&F mode.

[0041] Currently, mobile terminals need to continuously monitor all satellite broadcast signals to determine which satellites support S&F operations.

[0042] Based on this, the satellite communication method in this embodiment dynamically generates an S&F monitoring list through a high- and low-orbit satellite networking architecture, enabling precise operation between the mobile terminal and the ground gateway station.

[0043] The communication system described in this embodiment belongs to a regenerative payload architecture, including a high-orbit satellite and several low-orbit satellites. The low-orbit satellites support S&F operations and are equipped with base stations and core network elements. There are inter-satellite links between the low-orbit satellites and between the low-orbit satellites and the high-orbit satellites.

[0044] Based on the above-mentioned communication system with regenerative payload architecture, such as Figure 1The satellite communication method in this embodiment includes the following steps:

[0045] S1: Receive the mobile terminal's movement trajectory uploaded by the low-orbit satellite via the high-orbit satellite, as well as the location information of the ground gateway station and the ephemeris information of the low-orbit satellite related to the area where the mobile terminal is currently and for a period of time in the future via the ground gateway station.

[0046] S2: In the high-orbit satellite, based on the ephemeris information and the location of the ground gateway station, calculate the feeder link connection period between each low-orbit satellite and each ground gateway station;

[0047] S3: Among the high-orbit satellites, based on the ephemeris information, the movement trajectory, and the feeder link connection period, select the low-orbit satellites that meet one of the following conditions to generate a monitoring list for S&F operations. The data items of the monitoring list include the low-orbit satellite identifier and the corresponding feeder link connection time and ground gateway identifier.

[0048] Condition 1: The service link between the mobile terminal and the mobile terminal is available within a specific future time period, and a feeder link connection can be established with at least one ground gateway station within that time period.

[0049] S4: Broadcast the monitoring list to the mobile terminal and the ground gateway station via high-orbit satellite.

[0050] Specifically, the high-orbit satellite generates the monitoring list based on the deployed edge computing server.

[0051] The monitoring list is used to indicate the dynamic operations of mobile terminals and ground gateway stations during S&F operations. That is, mobile terminals and ground gateway stations perform S&F operation-related actions based on the high-orbit satellites.

[0052] In step S1 above, the low-orbit satellite continuously senses the location changes of the mobile terminal (such as OTDOA positioning) through the on-board base station to generate a movement trajectory and uploads the data to the high-orbit satellite through the inter-satellite link.

[0053] Ground gateway stations inject their own geographical location information and the orbital parameters (including orbital altitude, inclination, overpass time window, etc.) of associated low-Earth orbit satellites into high-Earth orbit satellites.

[0054] In step S2 above, the high-orbit satellite uses a satellite orbital dynamics model to predict the real-time position and velocity of the low-orbit satellite based on ephemeris information; and, combined with the location of the ground gateway station, calculates the visible time window (i.e., the feeder link connection period) between the low-orbit satellite and the ground gateway station. For example, if the orbital inclination of the low-orbit satellite LEO-1 is 55°, and the ground gateway station GW-5 is located at 116°E, 40°N, then the available period of the feeder link between LEO-1 and GW-5 is 13:15-13:30 UTC daily.

[0055] On the other hand, during S&F operations, the mobile terminal only listens for paging messages from the LEO satellites in the monitoring list, and shuts down the radio frequency module during idle time to save power. The ground gateway station only transmits mobile termination data through the LEO satellites in the monitoring list, and preloads MT data according to the time window of the feeder link connection cycle in the monitoring list.

[0056] When the feeder link is disconnected (i.e., the S&F operation ends), the mobile terminal immediately initiates registration with the next available low-Earth orbit satellite in the monitoring list, and the ground gateway station stops sending data.

[0057] The aforementioned satellite communication method first generates a monitoring list through joint filtering based on mobile terminal trajectories, low-Earth orbit satellite ephemeris, and feeder link cycles. Only low-Earth orbit satellites that simultaneously meet the requirements of service link availability (covering mobile terminals) and feeder link availability (covering ground gateway stations) within a specific future time period are selected, avoiding mobile terminals listening to invalid satellites. The ground gateway station only needs to send MT data to satellites in the monitoring list, reducing redundant data transmission.

[0058] Secondly, the complex calculations involving the fusion of multi-source data are handled by high-orbit satellites, alleviating the computing power bottleneck of low-orbit satellites; moreover, by utilizing the wide-area coverage capability of high-orbit satellites, monitoring lists are broadcast synchronously to mobile terminals and ground gateways across the entire region, effectively reducing the delay in issuing instructions.

[0059] Furthermore, the monitoring list accurately predicts the feeder connection time window between each LEO satellite and various ground gateway stations, avoiding data loss due to satellite-to-ground link mismatch. During S&F operations, ground gateway stations preload MT data according to the time windows in the monitoring list, enabling LEO satellites to immediately forward cached data when the feeder link is restored, reducing end-to-end interruption time to less than a second.

[0060] In addition, the mobile terminal only listens to low-Earth orbit satellites in the monitoring list, and the ground gateway station only sends data to low-Earth orbit satellites in the monitoring list. Both parties perform operations based on the same spatiotemporal reference, eliminating registration conflicts caused by information asynchrony in traditional schemes (such as the ground gateway station sending MT data to satellites not covered).

[0061] On the other hand, in the high-orbit satellite, the duration of S&F operation is also generated based on the feeder link connection cycle, and the duration is broadcast to the mobile terminal and the ground gateway station.

[0062] In S&F operations, duration refers to the complete time window from when the feeder link is disconnected to when it is reconnected, that is, the period during which the mobile terminal maintains a service link connection with the LEO satellite, but the LEO satellite cannot establish a feeder link with the ground gateway station.

[0063] Based on the ephemeris information of the low-orbit satellite and the location of the ground gateway station, the high-orbit satellite predicts the feeder link disconnection time (T_start) and reconnection time (T_end); then calculates the time difference ΔT = T_end - T_start as the duration of the S&F operation.

[0064] Furthermore, when the duration of the S&F operation ends, the mobile terminal initiates a registration request to the corresponding low-Earth orbit satellite in the monitoring list, and the ground gateway station transmits MT data to the corresponding low-Earth orbit satellite to restore real-time communication.

[0065] In other words, from the perspective of the terminal side:

[0066] After receiving the duration, the mobile terminal only listens for satellite paging in the monitoring list within the ΔT time window;

[0067] Outside the ΔT window (i.e., during non-S&F operation periods), resume full-band monitoring or enter sleep mode.

[0068] For the ground gateway station side:

[0069] The ground gateway station predicts the timing of MT data transmission based on the duration and only sends data to the satellites in the monitoring list immediately after ΔT ends.

[0070] For example: If ΔT = 14:00-14:15UTC, the ground gateway station starts MT data transmission at 14:15:00.

[0071] Therefore, in this embodiment, by clearly defining the start and end times of the S&F operation, the mobile terminal can precisely control the activation period of the radio frequency module and disable unnecessary listening functions outside the ΔT window, which effectively and significantly reduces power consumption compared to the traditional continuous listening mode.

[0072] Moreover, the mobile terminal and the ground gateway station perform operations based on the same ΔT, eliminating communication conflicts caused by time errors (such as the gateway station sending data too early, causing satellite buffer overflow), thus greatly improving the success rate of MT data transmission.

[0073] In addition, the ground gateway station precisely schedules MT data transmission according to ΔT to avoid attempting transmission during periods when the feeder link is unavailable, thus saving satellite backhaul bandwidth.

[0074] On the other hand, the method by which the low-orbit satellite acquires the movement trajectory of the mobile terminal includes:

[0075] The network data analysis function (NWDAF) in the core network element receives the dynamic location information of the mobile terminal uploaded by the base station in real time, and the NWDAF generates the movement trajectory based on the dynamic location information.

[0076] On the other hand, the high-orbit satellites and the low-orbit satellites interact through User Plane Functions (UPF).

[0077] Specifically, such as Figure 2 The process of acquiring the movement trajectory in low orbit is as follows:

[0078] 1. The Access and Mobility Management Function (AMF) supports location reporting. The AMF requires the base station (gNB) to provide the current location information of the mobile terminal (UE), the location information and timestamp of the last time the UE was camped.

[0079] 2. gNB can detect changes in the UE's location using common positioning technologies, such as cell ID positioning, OTDOA positioning, and UTDOA positioning.

[0080] 3. After the gNB detects a change in the UE's location, it reports the changed location to the AMF;

[0081] 4. NWDAF subscribes to the UE's location information from AMF;

[0082] 5. The AMF dynamically sends the UE's location report to the NWDAF. That is, every time the AMF receives the latest location information reported by the gNB, it will send it to the NWDAF.

[0083] 6. NWDAF analyzes the UE's movement trajectory based on the location information reported multiple times by AMF;

[0084] 7. NWDAF sends the analysis results to UPF;

[0085] 8. The UPF on the low-Earth orbit satellite transmits the analysis results to the UPF on the high-Earth orbit satellite via inter-satellite links.

[0086] The present invention also discloses another satellite communication system, which includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the satellite communication method as described above. The processor may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, used to execute relevant programs to implement the functions required by the modules in the satellite communication system of the embodiments of this application, or to execute the satellite communication method of the method embodiments of this application.

[0087] This invention also discloses a computer-readable storage medium comprising a computer program executable by a processor to perform the satellite communication method described above. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center integrating one or more available media. The available medium can be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as digital versatile discs (DVDs), or semiconductor media, such as solid-state drives (SSDs).

[0088] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the aforementioned satellite communication method.

[0089] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A satellite communication method based on store-and-forward (S&F) operation for high-low orbit satellite networking communication system, characterized in that, The communication system comprises a high orbit satellite and a plurality of low orbit satellites, the low orbit satellites support S&F operation, base stations and core network elements are deployed on the low orbit satellites, there are inter-satellite links between the low orbit satellites, there are inter-satellite links between the low orbit satellites and the high orbit satellite, and the method comprises: Receiving, by the high orbit satellite, a mobile trajectory of a mobile terminal uploaded by the low orbit satellites, and position information of a ground gateway station uploaded by the ground gateway station, and ephemeris information of the low orbit satellites related to an area where the mobile terminal is currently located and will be located in a future period of time; In the high orbit satellite, calculating, according to the ephemeris information and the position of the ground gateway station, a feeder link connection period of each of the low orbit satellites and each of the ground gateway stations; In the high orbit satellite, filtering, based on the ephemeris information, the mobile trajectory, and the feeder link connection period, the low orbit satellites that meet condition one to generate a monitoring list for S&F operation, a data item of the monitoring list comprising a low orbit satellite identifier and corresponding feeder link connection time and ground gateway station identifier; Condition one: a service link between the mobile terminal and the low orbit satellite is available in a future specific period of time, and a feeder link connection with at least one of the ground gateway stations can be established in the period of time; Broadcasting, by the high orbit satellite, the monitoring list to the mobile terminal and the ground gateway station; The monitoring list is used to indicate dynamic operation of the mobile terminal and the ground gateway station during S&F operation.

2. The store-and-forward (S&F) operation based satellite communication method according to claim 1, wherein, During S&F operation, the mobile terminal only listens to a paging message of the low orbit satellite in the monitoring list, and the ground gateway station only transmits mobile terminated data through the low orbit satellite in the monitoring list.

3. The store-and-forward (S&F) operation based satellite communication method according to claim 1, wherein, In the high orbit satellite, a duration of S&F operation is also generated based on the feeder link connection period, and the duration is broadcast to the mobile terminal and the ground gateway station.

4. The store-and-forward (S&F) operation based satellite communication method according to claim 3, wherein, At the end of the duration of S&F operation, the mobile terminal initiates a registration request to the corresponding low orbit satellite in the monitoring list, and the ground gateway station transmits MT data to the corresponding low orbit satellite to restore real-time communication.

5. The store-and-forward (S&F) operation based satellite communication method according to claim 1, wherein, The method for the low orbit satellite to obtain the mobile trajectory of the mobile terminal comprises: Receiving, in real time, dynamic position information of the mobile terminal uploaded by the base station based on a network data analysis function in the core network element, and generating the mobile trajectory based on the dynamic position information by the network data analysis function.

6. The store-and-forward (S&F) operation based satellite communication method according to claim 1, wherein, The high orbit satellite generates the monitoring list based on a deployed edge computing server.

7. The store-and-forward (S&F) operation based satellite communication method according to claim 1, wherein, The high orbit satellite and the low orbit satellite interact through a user plane function.

8. A satellite communication system based on store-and-forward (S&F) operation, characterized by The communication system performs communication work based on the satellite communication method of any one of claims 1 to 7.

9. A satellite communication system, characterized by Comprise: One or more processors; Memory; And one or more programs, wherein one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs comprising instructions for executing the satellite communication method of any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer program can be executed by a processor to complete the satellite communication method as claimed in any one of claims 1 to 7.

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