Low-orbit narrow-band internet-of-things constellation system and method based on satellite processing and hybrid backhaul

Abstract

The invention discloses a low-orbit narrowband Internet of Things constellation system and method based on satellite processing and hybrid backhaul, and belongs to the technical field of satellite communication. Comprising a space section formed by a plurality of satellites deployed in a specific inclination angle low earth orbit, a ground section provided with a plurality of gateway stations and operation and control centers in a global middle and low latitude area, and a plurality of Internet of Things terminals; wherein the satellite is configured with a communication load with on-satellite processing capability, and is used for receiving and processing an uplink short message sent by the terminal, and adaptively selecting a real-time forwarding mode or a store-and-forward mode to return the processed data to the ground based on the real-time visibility of the satellite and the gateway station. Through optimization design of constellation configuration and combination of on-satellite processing and hybrid backhaul mechanisms, efficient and reliable coverage of global key areas is realized under the condition that inter-satellite links are not needed, terminal power consumption and system complexity and cost are remarkably reduced, and the method is particularly suitable for burst short message services of wide-area distributed Internet of Things.

Description

Technical Field

[0001] This invention belongs to the field of satellite communication technology, and in particular relates to a low-orbit narrowband IoT constellation system and method based on on-board processing and hybrid backhaul. Background Technology

[0002] With the rapid development of IoT technology, the demand for seamless global wireless connectivity is becoming increasingly urgent. However, terrestrial cellular networks only cover about 20% of the land area, leaving a huge gap in connectivity for IoT devices in oceans, deserts, remote mountainous areas, and vast rural regions. Low Earth orbit (LEO) satellite communication networks, with their global coverage, low latency, and decreasing costs, have become an ideal solution to fill this gap.

[0003] Currently, deployed or planned low-Earth orbit satellite constellations mainly fall into two categories: large constellations aimed at high-speed broadband access and narrowband constellations aimed at specific Internet of Things (IoT) services. The former is complex and has high terminal costs, which is seriously inconsistent with the core requirements of IoT terminals: "small data, low power consumption, and low cost." While the latter is more targeted, it still faces the following key challenges in system design: Mismatch between coverage efficiency and business needs: Many IoT constellations use polar orbits to achieve uniform global coverage, but global IoT businesses (such as agriculture, logistics, and environmental monitoring) are highly concentrated in low- and mid-latitude regions. Polar orbit constellations have long revisit cycles near the equator, which cannot meet the near-real-time data requirements of low- and mid-latitude regions, resulting in poor utilization of satellite resources.

[0004] The reliability bottleneck of global data backhaul: For low-Earth orbit constellations without inter-satellite links, satellites can only transmit data when flying over ground stations. When satellites receive terminal data in areas without ground stations, such as the ocean and polar regions, if they cannot transmit it in real time, the traditional approach is to discard it or wait for complex routing. This leads to data loss or uncontrollable latency, making it impossible to achieve truly reliable global service.

[0005] High terminal power consumption and cost: To overcome the huge space link loss, traditional satellite IoT terminals require watt-level or higher transmission power and complex antennas, resulting in large device size, high power consumption and high cost, which seriously hinders large-scale application. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a low-Earth orbit narrowband IoT constellation system and method based on on-board processing and hybrid backhaul, thereby resolving the issues present in the prior art.

[0007] To achieve the above objectives, the present invention provides a low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul, comprising: The space segment consists of a constellation of multiple satellites deployed in low Earth orbit; The ground segment includes multiple gateway stations and operations control centers located in mid- and low-latitude regions around the world; The user terminal segment includes several Internet of Things (IoT) terminals; The satellites in the space segment are equipped with communication payloads with onboard processing capabilities to receive and process uplink short messages sent by the IoT terminals, and to select a forwarding mode to transmit the processed data back to the ground segment based on the real-time visibility between the satellite and the gateway station; the operation and control center is used to manage the constellation and provide communication parameters for the IoT terminals.

[0008] Optionally, the constellation is the Walker Delta constellation, with an orbital altitude of 900 kilometers and an orbital inclination of 45 degrees.

[0009] Optionally, the satellite is a micro / nano satellite, and the communication payload operates in the U / V band and adopts a linear frequency modulation spread spectrum communication system.

[0010] Optionally, the communication payload includes: Multiple uplink channels are used to receive uplink short messages sent concurrently by the IoT terminal; At least one downlink channel is used for broadcasting system information and common configuration information; The on-board processing unit is used to demodulate, decode, and package the uplink short messages; Onboard memory is used to store data processed by the onboard processing unit.

[0011] Optionally, the forwarding mode includes real-time forwarding mode and store-and-forward mode; When the satellite is within the visible range of any gateway station, the real-time forwarding mode is used to immediately transmit the processed data to that gateway station. When the satellite is not within the visible range of any gateway station, the store-and-forward mode is used to temporarily store the processed data in the onboard memory. The processed data will be downloaded when the satellite enters the visible range of any gateway station.

[0012] The present invention also provides an Internet of Things (IoT) data communication method based on the above system, comprising: The operations control center manages the constellation and provides communication parameters for IoT terminals; The IoT terminal sends uplink short messages to the overhead satellite within a predetermined time window based on the communication parameters. The satellite receives and processes the uplink short messages through a communication payload with onboard processing capabilities; Based on its real-time visibility with ground gateways, the satellite selects either real-time forwarding mode or store-and-forward mode to transmit the processed data back to the ground segment.

[0013] Optionally, the process by which the IoT terminal sends uplink short messages based on communication parameters includes: Receive system information and common configuration information from satellite broadcast; maintain deep sleep outside the communication time window according to the communication parameters, and wake up within the communication time window; and burst-send the uplink short message with low transmission power.

[0014] Optionally, the process of satellite receiving and processing uplink short messages includes: Short messages are received from IoT terminals through multiple uplink channels; the onboard processing unit demodulates, decodes, and packages the received short message signals in real time.

[0015] Optionally, the process of a satellite selecting a backhaul mode includes: Determine whether the satellite is within the visible range of any ground gateway station; if it is within the visible range, activate the real-time forwarding mode and immediately send the processed data packets to the gateway station via the downlink; if it is not within the visible range, activate the store-and-forward mode and store the processed data packets in the onboard memory; when the satellite moves into the visible range of any gateway station, trigger the batch downlink of the stored data packets.

[0016] Optionally, the operations control center can merge the data transmitted back to various ground gateways via real-time forwarding mode and store-and-forward mode to form a complete terminal data stream.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: Highly aligned with business needs and exceptional efficiency: Employing a 45° inclination Walker constellation, valuable orbital and beam resources are concentrated to serve the most densely populated low- and mid-latitude regions for IoT business. Compared to polar orbit constellations that aim for uniform global coverage, with the same number of satellites, the average revisit cycle in key low- and mid-latitude areas can be reduced from several hours to less than minutes, significantly improving the timeliness of data collection and the utilization efficiency of satellite resources.

[0018] Achieving reliable global service without inter-satellite links: The key to this invention is its unique "on-board processing + hybrid backhaul" mechanism. Without employing expensive and complex inter-satellite link technology, it ensures reliable backhaul of data collected from any location globally (including ground station blind spots) through intelligent switching and combination of "real-time forwarding" and "store-and-forward," achieving a theoretical data reachability exceeding 99.9%, thus solving a fundamental challenge for global service of low-Earth orbit IoT constellations.

[0019] The terminal achieves extremely low power consumption and low cost: Through a combined design of "ground-based precise ephemeris assistance + on-board high-sensitivity receiver (CSS) + simplified single-burst communication," the terminal's average power consumption mainly depends on the dormant current, enabling a battery life of over 5 years at a daily reporting frequency. On-board processing simplifies the terminal protocol, making terminal chip-based and modular development possible, laying the foundation for low-cost terminals required for massive deployment.

[0020] The system boasts large capacity and flexible expansion: nearly 100 uplink channels and a short message burst design enable a single satellite to support an extremely high number of concurrent terminals. Based on a constellation of 50kg-class micro-nano satellites, the construction cycle is short and the cost is controllable. The system capacity and coverage performance can be smoothly expanded according to business growth needs by increasing the number of satellites in a single orbital plane or supplementing orbital planes. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the overall architecture of the constellation system according to an embodiment of the present invention; Figure 2 A heatmap showing the global average revisit cycle distribution of the Walker constellation (36 stars) at a 45° tilt angle, according to an embodiment of the present invention. Figure 3 This is a functional block diagram of the satellite communication payload and a flowchart of the hybrid backhaul logic judgment in an embodiment of the present invention. Figure 4 This is a timeline diagram showing the entire process of data acquisition and successful data transmission back to the data center for the IoT terminal using the present invention. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0024] Example 1 like Figure 1 As shown, this embodiment provides a low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul, including: a space segment, a ground segment, and a user terminal segment.

[0025] (1) Spatial segment: Constellation Configuration: The Walker Delta constellation configuration is adopted at an altitude of 900 km and an inclination of 45°. Preferably, 36 operational satellites are evenly distributed across 6 orbital planes, forming an optimized coverage network for the region between 45° North and 45° South latitude, covering more than 85% of the global population and major economic activity areas. Figure 2 As shown, this constellation configuration can achieve optimized coverage of mid- and low-latitude regions, significantly shortening the revisit cycle.

[0026] Satellite platform: The micro-nano satellite platform adopts a standardized and modular design, with a single satellite weighing approximately 50 kg, making it suitable for low-cost mass production and rapid launch and networking.

[0027] Communication Payload: Each satellite carries a U / V band narrowband IoT payload, employing a linear frequency modulation spread spectrum communication system. This payload has onboard signal processing capabilities, specifically configured as follows: Uplink: It is designed with 90 independent channels and adopts a contention-based random access protocol to support the concurrent short message upload of a large number of terminals.

[0028] Downlink: It is designed with two broadcast channels for sending system information, synchronization signals and brief terminal control commands.

[0029] Processing unit: Demodulates, decodes, parses protocols, and packages data in real time the received CSS signals to form standardized application layer data packets.

[0030] Large-capacity storage: Equipped with onboard solid-state storage for temporarily storing processed data packets when no ground station is visible.

[0031] The functional module block diagram and hybrid backhaul logic judgment process of the communication payload are as follows: Figure 3 As shown.

[0032] (2) Ground section: Gateway network: Multiple gateway stations are built in low- and mid-latitude regions around the world (such as East Asia, Western Europe, North America, South America, and Australia). These gateway stations are equipped with large-aperture antennas and high-sensitivity receivers, and are responsible for establishing high-speed data transmission links with overhead satellites.

[0033] Operations Control and Data Center: Responsible for constellation management, orbit control, mission planning, and collecting data transmitted from all gateway stations for unified processing, distribution, and storage. Based on precise constellation ephemeris data, the Operations Control Center calculates and dynamically updates the optimal communication time window and parameters for each registered terminal.

[0034] (3) User terminal segment: The terminal features an ultra-low power design, with built-in satellite orbit prediction algorithms and a simplified protocol stack. It remains in deep sleep mode (μA-level current) most of the time, only waking up before the pre-calculated satellite overpass service window to receive satellite broadcasts and burst-send a short CSS modulated message of tens to hundreds of bytes in length within 1-2 seconds at a transmit power of 100-2000 milliwatts.

[0035] The core innovation of this invention lies in the hybrid data backhaul mechanism of the above system, the process of which is as follows: Step S1: When the satellite flies over its coverage area, it receives CSS burst short messages sent by a large number of terminals through nearly a hundred uplink channels.

[0036] Step S2: The on-board processing unit demodulates, decodes, and formats the received signals in real time to extract valid application data packets.

[0037] Step S3: The satellite automatically determines whether it is currently within the visible range of any ground gateway station: If so, the "real-time forwarding mode" is executed: the data packet generated in step S2 is immediately sent to the ground station via the downlink data transmission link, and then transmitted back to the data center via the ground network. This mode has extremely short end-to-end latency, usually less than 1 minute.

[0038] If not, then execute "store-and-forward mode": package the data packet generated in step S2, along with metadata such as reception time and terminal ID, and store it in the onboard large-capacity storage.

[0039] Step S4: The satellite in "store-and-forward mode" continues to operate. When its orbit moves into the visible range of the next ground gateway station, it automatically triggers downlink transmission of memory data, and transmits the temporarily stored data packets to the ground station in batches and efficiently.

[0040] Step S5: The ground control center merges, deduplicates, and sorts the data transmitted back through the two modes by time to form a complete terminal data stream, which is then provided to the user.

[0041] Figure 4 The entire timeline of the IoT terminal's data acquisition and successful data transmission back to the data center is demonstrated, showcasing the core mechanism of this invention.

[0042] Example 2 This embodiment provides a low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul, including: a space segment, a ground segment, and a user terminal segment.

[0043] The space segment consists of a constellation of multiple satellites deployed in low Earth orbit; The ground segment includes multiple gateway stations deployed in mid- and low-latitude regions around the world; The user terminal segment includes several Internet of Things (IoT) terminals used for collecting and sending short message data; The satellites in the space segment are equipped with communication payloads with onboard processing capabilities, which are used to receive and process uplink short messages sent by terminals, and, based on the real-time visibility between the satellite and the ground gateway, select real-time forwarding mode or store-and-forward mode to transmit the processed data back to the ground segment.

[0044] The space segment adopts the Walker Delta constellation configuration, with an orbital altitude of 900 kilometers and an orbital inclination of 45 degrees.

[0045] like Figure 2 As shown, this constellation configuration can achieve optimized coverage of mid- and low-latitude regions, significantly shortening the revisit cycle.

[0046] The Walker Delta constellation consists of operational satellites distributed across multiple orbital planes. These operational satellites are micro- and nano-satellites weighing approximately 50 kilograms each, and their communication payloads operate in the U / V band and employ a linear frequency modulation spread spectrum communication system.

[0047] The communication payload specifically includes: multiple uplink channels for receiving concurrent access from a large number of terminals, at least one downlink channel for broadcasting system information and common configuration information, an on-board processing unit for demodulating and decoding uplink signals, and an on-board memory for temporarily storing data when no ground station is visible.

[0048] The functional module block diagram and hybrid backhaul logic judgment process of the communication payload are as follows: Figure 3 As shown.

[0049] Real-time forwarding mode refers to the process where, when the satellite is within the visible range of any ground gateway station, the processed data packets are immediately sent to that ground station via the downlink. Store-and-forward mode refers to the process where, when the satellite is not within the visible range of any ground gateway station, the processed data packets are temporarily stored in the onboard memory, and then the temporarily stored data packets are downloaded in batches when the satellite enters the visible range of any ground gateway station.

[0050] The ground segment also includes an operations control center, which calculates and sends the predicted communication time window and communication parameters between each user terminal and the satellite based on the accurate ephemeris of the constellation, so as to guide the terminal to send short messages in a low-power burst mode within a specific window.

[0051] This embodiment also provides an IoT data communication method based on the above system, including the following steps: Within its coverage area, the satellite receives burst short messages sent by user terminals via the uplink channel; The onboard processing unit demodulates, decodes, and packages the received short message signals in real time. Determine whether the satellite is currently within the visible range of the ground gateway station; If it is within the visible range, the real-time forwarding mode is activated, and the data packet is immediately transmitted to the ground station; If the satellite is not within the visible range, the store-and-forward mode is activated, storing the data packets in the onboard memory. Downlink transmission is then triggered when the satellite moves into the visible range of the ground station.

[0052] Before sending a short message, the user terminal receives and parses the broadcast information from the satellite to obtain the precise communication time window. It remains in deep sleep for most of the time outside the window, and only wakes up within the window to complete the burst transmission of short messages with low transmission power.

[0053] The ground control center merges and processes the data transmitted back through real-time forwarding mode and store-and-forward mode to form a complete terminal data stream.

[0054] Figure 4 The entire timeline of the IoT terminal's data acquisition and successful data transmission back to the data center is demonstrated, showcasing the core mechanism of this invention.

[0055] Example: Build an IoT constellation system for global wildlife tracking and environmental monitoring.

[0056] System Deployment: First, 36 functionally identical operational satellites will be launched in batches and deployed into six circular orbital planes at an altitude of 900 km and an inclination of 45°. Six satellites will be deployed in each orbital plane, with a phase factor of 1, forming a stable WalkerDelta constellation. Subsequently, two additional sun-synchronous orbit satellites with an inclination of approximately 97° can be launched to moderately enhance coverage capabilities in high-latitude regions.

[0057] The construction of one gateway station each in Iceland, Singapore, South Africa, Northwest China, and Chile ensures basic continuous visibility over low and mid-latitude regions worldwide.

[0058] Mass-produced terminal modules based on the communication protocol of this invention are provided for integration into devices such as wildlife tracking collars, marine buoys, and forest fire monitoring sensors.

[0059] Workflow: A Tibetan antelope wearing a tracking collar roams in the Hoh Xil region. Sensors inside the collar collect location and body temperature data every hour.

[0060] The terminal's built-in forecasting algorithm calculates the service window for the next overhead satellite (such as "Tianqi-15") based on the simplified ephemeris updated from satellite broadcasts, from 14:25 to 14:28 Beijing time. The terminal wakes up at 14:24:50.

[0061] At 14:25:05, the terminal received the downlink broadcast signal from the Tianqi-15 satellite and completed synchronization. Subsequently, at 14:25:20, it burst-sent a short message containing encrypted ID, coordinates, body temperature, and battery level within 1.5 seconds at a power of 300 milliwatts.

[0062] Scenario A (Real-time Relay): The Tianqi-15 satellite is currently flying over a gateway station in northwestern China. Upon receiving the signal, the onboard payload immediately performs CSS demodulation, decryption, and packaging to generate a standard data packet. Because the data packet is visible to the ground station, it is transmitted in real-time to the northwestern ground station via the downlink data transmission link, and then delivered to the data center in Beijing via a dedicated network at 14:25:50. Researchers observed the Tibetan antelope's location updates in near real-time.

[0063] Scenario B (Storage-and-Forward): A research vessel sailing in the South Pacific automatically collects and transmits data at 3:00 AM (local time) using its temperature, thermal, and depth (TDT) instrument. At this time, the Tianqi-22 satellite, passing overhead, is located in the central Pacific Ocean and is not within the visibility range of any ground station. After processing the data, the satellite stores it in its onboard memory. The satellite continues flying northwest and enters the visibility range of the Hainan ground station approximately 50 minutes later. The satellite automatically downloads multiple data packets, including the research vessel's data, in batches from its memory. The data is finally transmitted back to the data center approximately one hour after collection.

[0064] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul, characterized in that, include: The space segment consists of a constellation of multiple satellites deployed in low Earth orbit; The ground segment includes multiple gateway stations and operations control centers located in mid- and low-latitude regions around the world; The user terminal segment includes several Internet of Things (IoT) terminals; The satellites in the space segment are equipped with communication payloads with onboard processing capabilities to receive and process uplink short messages sent by the IoT terminals, and to select a forwarding mode to transmit the processed data back to the ground segment based on the real-time visibility between the satellite and the gateway station; the operation and control center is used to manage the constellation and provide communication parameters for the IoT terminals.

2. The low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul according to claim 1, characterized in that, The constellation in question is the Walker Delta, with an orbital altitude of 900 kilometers and an orbital inclination of 45 degrees.

3. The low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul according to claim 1, characterized in that, The satellite is a micro-nano satellite, and the communication payload operates in the U / V band and adopts a linear frequency modulation spread spectrum communication system.

4. The low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul according to claim 1, characterized in that, The communication payload includes: Multiple uplink channels are used to receive uplink short messages sent concurrently by the IoT terminal; At least one downlink channel is used for broadcasting system information and common configuration information; The on-board processing unit is used to demodulate, decode, and package the uplink short messages; Onboard memory is used to store data processed by the onboard processing unit.

5. The low-Earth orbit narrowband IoT constellation system based on on-board processing and hybrid backhaul according to claim 1, characterized in that, The forwarding modes include real-time forwarding mode and store-and-forward mode; When the satellite is within the visible range of any gateway station, the real-time forwarding mode is used to immediately transmit the processed data to that gateway station. When the satellite is not within the visible range of any gateway station, the store-and-forward mode is used to temporarily store the processed data in the onboard memory. The processed data will be downloaded when the satellite enters the visible range of any gateway station.

6. An Internet of Things (IoT) data communication method based on the system according to any one of claims 1-5, characterized in that, include: The operations control center manages the constellation and provides communication parameters for IoT terminals; The IoT terminal sends uplink short messages to the overhead satellite within a predetermined time window based on the communication parameters. The satellite receives and processes the uplink short messages through a communication payload with onboard processing capabilities; Based on its real-time visibility with ground gateways, the satellite selects either real-time forwarding mode or store-and-forward mode to transmit the processed data back to the ground segment.

7. The method according to claim 6, characterized in that, The process by which an IoT terminal sends an uplink short message based on communication parameters includes: Receive system information and common configuration information from satellite broadcast; maintain deep sleep outside the communication time window according to the communication parameters, and wake up within the communication time window; and burst-send the uplink short message with low transmission power.

8. The method according to claim 6, characterized in that, The process of a satellite receiving and processing uplink short messages includes: Short messages are received from IoT terminals through multiple uplink channels; the onboard processing unit demodulates, decodes, and packages the received short message signals in real time.

9. The method according to claim 6, characterized in that, The process of a satellite selecting a return mode includes: Determine whether the satellite is within the visible range of any ground gateway station; if it is within the visible range, activate the real-time forwarding mode and immediately send the processed data packets to the gateway station via the downlink; if it is not within the visible range, activate the store-and-forward mode and store the processed data packets in the onboard memory; when the satellite moves into the visible range of any gateway station, trigger the batch downlink of the stored data packets.

10. The method according to claim 6, characterized in that, The operations control center integrates and processes the data transmitted back to various ground gateways via real-time forwarding mode and store-and-forward mode to form a complete terminal data stream.

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