Data transmission method and system of satellite Internet of Things

Abstract

The invention relates to the technical field of transmission, and provides a data transmission method and system for a satellite Internet of Things, and the method comprises the steps: determining the frequency domain sub-band range and channel utilization rate of each service according to the broadcast information of a satellite; checking the sub-band channel utilization rate in the target range according to the length of the to-be-transmitted service data; determining an access sending mode of the to-be-transmitted service data according to the sub-band channel utilization rate of the target range and a preset transmission threshold; the access sending mode is a mixed mode including data direct transmission, two-step random access and reselection of sending sub-bands. According to the invention, resource allocation can be optimized, the ground terminal access efficiency and the resource utilization rate are improved, and massive terminal access and efficient data transmission are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transmission, in particular to a satellite Internet of Things data transmission method and system. BACKGROUND

[0002] Satellite Internet of Things is a new network system deeply integrated with satellite communication and Internet of Things technology. It takes satellite network as the information carrier and builds a new generation of network architecture for human, machine and object interconnection. In terms of providing low-power, small-data and wide-coverage data connection services, satellite Internet of Things shows significant advantages. In the 5G era, it has become a key supplement and extension of ground Internet of Things; looking forward to the 6G era, it is an essential component of space-air-ground integrated collaborative network.

[0003] Compared with high-orbit satellite Internet of Things, low-orbit satellite Internet of Things has obvious advantages of low delay and low power consumption. However, low-orbit satellites also have characteristics of high dynamics and short transit time, which undoubtedly brings new challenges to the mobility management and efficient data transmission of low-orbit satellite constellation. SUMMARY

[0004] The present application provides a satellite Internet of Things data transmission method and system to solve the defects of low-orbit satellite Internet of Things in data transmission in the prior art. The present application can optimize resource allocation, improve ground terminal access efficiency and resource utilization, and realize massive terminal access and efficient data transmission.

[0005] The present application provides a satellite Internet of Things data transmission method applied to a ground terminal, which comprises: determining the frequency domain sub-band range and channel utilization rate of each service according to the broadcast information of a satellite; checking the sub-band channel utilization rate in the target range according to the length of the to-be-transmitted service data; determining the access transmission mode of the to-be-transmitted service data according to the sub-band channel utilization rate of the target range and a preset transmission threshold; the access transmission mode is a hybrid mode including data direct transmission, two-step random access and reselection of transmission sub-band.

[0006] According to the satellite Internet of Things data transmission method provided by the present application, the broadcast information of the satellite includes satellite identification information, available time-frequency resources of a random access channel, sub-band channel utilization rate and utilization threshold value of each service.

[0007] According to the satellite Internet of Things data transmission method provided by the present application, checking the sub-band channel utilization rate in the target range according to the length of the to-be-transmitted service data comprises: determining the rate of the to-be-transmitted service data according to the length of the to-be-transmitted service data and a preset time slot length; and checking the sub-band channel utilization rate corresponding to the rate interval of the to-be-transmitted service data based on the rate of the to-be-transmitted service data.

[0008] According to the satellite Internet of Things data transmission method provided by the application, the access transmission mode of the to-be-transmitted service data is determined according to the sub-band channel utilization rate of the target range and a preset transmission threshold, and the to-be-transmitted service data is transmitted on the sub-band frequency point corresponding to the direct transmission channel utilization rate in the case that the direct transmission channel utilization rate exists in the sub-band channel utilization rate of the target range.

[0009] According to the satellite Internet of Things data transmission method provided by the application, the access transmission mode of the to-be-transmitted service data is determined according to the sub-band channel utilization rate of the target range and a preset transmission threshold, and the to-be-transmitted service data is transmitted on the sub-band frequency point corresponding to the direct transmission channel utilization rate in the case that the direct transmission channel utilization rate exists in the sub-band channel utilization rate of the target range.

[0010] According to the satellite Internet of Things data transmission method provided by the application, the access transmission mode of the to-be-transmitted service data is determined according to the sub-band channel utilization rate of the target range and a preset transmission threshold, and the to-be-transmitted service data is transmitted on the sub-band frequency point corresponding to the direct transmission channel utilization rate in the case that the direct transmission channel utilization rate exists in the sub-band channel utilization rate of the target range.

[0011] The application further provides a satellite Internet of Things data transmission system applied to a ground terminal, and the system comprises: a utilization rate determination module configured to determine the frequency domain sub-band range and channel utilization rate of each service according to the broadcast information of a satellite; a viewing module configured to view the sub-band channel utilization rate in a target range according to the length of to-be-transmitted service data; and a transmission mode determination module configured to determine the access transmission mode of the to-be-transmitted service data according to the sub-band channel utilization rate of the target range and a preset transmission threshold; the access transmission mode is a hybrid mode comprising data direct transmission, two-step random access and reselected transmission sub-band.

[0012] The application further provides an electronic device comprising a memory, a processor and a computer program stored in the memory and running on the processor, and the processor implements the satellite Internet of Things data transmission method according to any one of the above-mentioned methods when executing the computer program.

[0013] The application further provides a non-transient computer readable storage medium having a computer program stored thereon, and the computer program is executed by a processor to implement the satellite Internet of Things data transmission method according to any one of the above-mentioned methods.

[0014] The application further provides a computer program product comprising a computer program which, when executed by a processor, implements the data transmission method of the satellite Internet of Things according to any one of the above.

[0015] The data transmission method and system of the satellite Internet of Things can optimize resource allocation, improve ground terminal access efficiency and resource utilization, and realize massive terminal access and efficient data transmission. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 is a flowchart of the data transmission method of the satellite Internet of Things provided by the application.

[0018] Figure 2 is a principle diagram of the data transmission method of the satellite Internet of Things provided by the application.

[0019] Figure 3 is a specific flowchart of the data transmission method of the satellite Internet of Things provided by the application.

[0020] Figure 4 is a structure diagram of the data transmission system of the satellite Internet of Things provided by the application.

[0021] Figure 5 is a structure diagram of the electronic device provided by the application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the application more clear, the technical solutions in the application will be described clearly and completely in the following with reference to the drawings in the application. Obviously, the described embodiments are some embodiments of the application, not all embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0023] Satellite Internet of Things (IoT) is a new type of network system that deeply integrates satellite communication and IoT technologies. Using satellite networks as the information carrier, it enables a new generation of networks that connect people, machines, and things. It has significant advantages in providing low-power, low-data-volume, and wide-coverage data connection services. In the 5G era, it is a key supplement and extension to terrestrial IoT, and in the future 6G era, it will be an essential component of an integrated air-space-ground collaborative network.

[0024] Low-Earth orbit (LEO) satellite IoT offers advantages such as low latency and low power consumption compared to high-Earth orbit (GEO) satellite IoT. However, LEO satellites also exhibit high dynamism and short transit times, posing new challenges to the mobility management and efficient data transmission of LEO communication constellations.

[0025] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a data transmission method for a satellite Internet of Things (IoT) provided by the present invention.

[0026] Please refer to Figure 2 , Figure 2 This is a schematic diagram illustrating the principle of a satellite Internet of Things (IoT) data transmission method provided by the present invention.

[0027] Please refer to Figure 3 , Figure 3 This is a schematic diagram illustrating the specific process of a data transmission method for a satellite Internet of Things (IoT) provided by the present invention.

[0028] This invention provides a data transmission method for satellite Internet of Things (IoT), applied to a ground terminal, the method comprising: 101: Determine the frequency domain subband range and channel utilization rate of each service based on the satellite broadcast information.

[0029] As a preferred embodiment, the satellite's broadcast information includes satellite identification information, available time-frequency resources for random access channels, sub-band channel utilization and utilization threshold values ​​for each service.

[0030] In satellite IoT systems, ground terminals typically consist of multiple sensors, exhibiting communication characteristics such as low mobility (even static), bursty non-real-time data uploads, and short message lengths with a certain periodicity. These characteristics provide favorable conditions for designing efficient wireless resource allocation and data transmission mechanisms.

[0031] The service characteristics of satellite IoT are that the service volume varies greatly at different times and in different geographical locations. Therefore, the satellite-to-ground air interface access method needs to be able to adaptively match the service volume to be transmitted and the existing channel resources, where both the service volume to be transmitted and the available channel resources can change over time.

[0032] The key to low-Earth orbit satellite Internet of Things (LEO) is to complete data transmission with minimal signaling interaction costs, thereby efficiently transmitting bursty short messages and improving the effectiveness and reliability of massive terminal data transmission.

[0033] This invention divides the wireless resources of the satellite-to-ground air interface into two dimensions: time and frequency (i.e., time slot and frequency point resources), and broadcasts the following information on the broadcast channel of each satellite: satellite identifier (satellite ID), available time and frequency resources of random access channel, frequency domain range of each data transmission sub-band and its channel utilization (sub-band utilization of uplink service channel), and preset utilization threshold values ​​(including first preset threshold value and second preset threshold value).

[0034] 102: Based on the length of the service data to be transmitted, check the sub-band channel utilization within the target range.

[0035] As a preferred embodiment, the sub-band channel utilization within the target range is viewed based on the length of the service data to be transmitted, including: determining the rate of the service data to be transmitted based on the length of the service data to be transmitted and the preset time slot length; and viewing the sub-band channel utilization within the rate range of the service data to be transmitted based on the rate of the service data to be transmitted.

[0036] In this embodiment, ground terminals for data acquisition are generally used in fixed scenarios, and the length of short messages reported by the same ground terminal is relatively stable and exhibits a certain periodicity in time. Based on this service characteristic, the uplink service channel rate of satellite IoT can be divided into sub-bands according to the actual typical scenario. Different sub-bands can correspond to different rate levels, such as forming... The system aggregates and configures the frequency ratio within sub-bands based on the proportion of services at different rates. Frequency information corresponding to different rates can be provided in the broadcast information, allowing the satellite to flexibly allocate the required radio resources for the coverage area of ​​different orbital arcs by referring to historical service information. Under a given radio frame length or time slot division, the division of the service rates in each sub-band is equivalent to the division of the data packet length that the ground terminal can transmit. By flexibly configuring the radio resources corresponding to different service rates and their usage thresholds on the broadcast channel, this invention aims to provide an adaptive usage method for the satellite-to-ground radio interface.

[0037] When a ground terminal has pending service data, it first reads the broadcast information and checks the sub-band channel utilization of each service. The length of the pending service data at the ground terminal is also considered. With system set time slot length The ratio, i.e., the rate of the service data to be transmitted. Meanwhile, the broadcast information indicates the corresponding rate. Sub-bands of the interval Channel utilization rate .

[0038] 103: Determine the access and transmission method for the service data to be transmitted based on the sub-band channel utilization rate of the target range and the preset transmission threshold; the access and transmission method includes a hybrid method of direct data transmission, two-step random access, and reselection of transmission sub-band.

[0039] As a preferred embodiment, the access and transmission method of the service data to be transmitted is determined based on the subband channel utilization rate of the target range and a preset transmission threshold, including: if there is a direct transmission channel utilization rate in the subband channel utilization rate of the target range, the service data to be transmitted is transmitted on the subband frequency point corresponding to the direct transmission channel utilization rate; the direct transmission channel utilization rate is lower than a first preset threshold value.

[0040] In this embodiment, when the sub-band channel utilization rate within the target range contains a direct transmission channel utilization rate (below the first preset threshold), the ground terminal directly transmits the service data to be transmitted on the sub-band frequency point corresponding to that direct transmission channel utilization rate. When sending the service data to be transmitted, the ground terminal should select an appropriate sub-band as much as possible and transmit the entire service data in one transmission.

[0041] As a preferred embodiment, the access and transmission method for the service data to be transmitted is determined based on the sub-band channel utilization rate of the target range and the preset transmission threshold, including: when the sub-band channel utilization rate of the target range is higher than the first preset threshold and lower than the second preset threshold, a two-step random access method is adopted to send the uplink preamble and the amount of service data to be transmitted on the random access channel, obtain the time-frequency resource allocation and the maximum allowed number of transmissions, and transmit the service data to be transmitted on the allocated time-frequency resources.

[0042] In this embodiment, when the utilization rate of all sub-band channels within the target range is higher than the first preset threshold but lower than the second preset threshold, time-frequency resource allocation is first obtained through random access, and then the service data to be transmitted is transmitted on the allocated time-frequency resources. The random access method used in this invention is a two-step random access designed for data acquisition services to reduce system overhead.

[0043] Specifically, the ground terminal receives broadcast information and obtains the configuration of the random access channel. If the ground terminal has service data to be transmitted, it sends an uplink preamble and the service data to be transmitted on the random access channel. The preamble should be selected from the access channel configuration information given in the system broadcast information; the amount of service data to be transmitted includes the available channel rate level and the number of uploads (the default number of uploads is 1).

[0044] After receiving the uplink random access information, the satellite first performs contention resolution. If the ground terminal is not selected for this data transmission due to a collision, no response is needed to the ground terminal. After the configured timer expires, the ground terminal will randomly back off for a period of time before retrying the uplink access.

[0045] If the contention resolution passes, the satellite needs to respond to the other party after the access control step. The random access response is transmitted on the downlink control channel, and its information includes timing adjustment information (TA) and the allocated channel configuration (such as the specific frequency, SF, etc.). Additionally, the satellite calculates the maximum number of uplink packets expected from the terminal on this channel (= number of uploads × maximum number of retransmissions). The round-trip propagation delay of the satellite-to-ground link is determined by the satellite's orbital altitude. After setting the maximum number of uplink packets for the target terminal, it means that the available time for the target terminal on the allocated channel is determined. Therefore, the satellite will start from the designated time slot (indicated by the TA), expecting to receive data on the allocated channel, and will actively release the radio resource after reserving the channel for time T. After receiving the random access response, the ground terminal performs synchronization and establishes a radio connection. At this time, the terminal state transitions from idle to connected. The ground terminal then transmits uplink data on the established radio connection.

[0046] Of course, when the ground terminal uses random access, it randomly selects time-frequency resources for access channels from the broadcast information based on the satellite identification information in the satellite's broadcast information to attempt access. The steps for two-step random access can be found in [link to documentation]. Figure 2 .

[0047] As a preferred embodiment, the access and transmission method of the service data to be transmitted is determined based on the sub-band channel utilization rate of the target range and the preset transmission threshold, including: when the sub-band channel utilization rate of the target range is higher than the second preset threshold value, the length of the service data to be transmitted is adjusted by padding bits, and the service data to be transmitted is re-transmitted on the sub-band corresponding to the sub-band channel utilization rate of the next higher order rate.

[0048] In this embodiment, when the subband channel utilization rate of the target range is higher than the second preset threshold, it means that the system load is high. The ground terminal uses bit padding to change the length of the service data to be transmitted, increase the physical layer rate, and reselect the subband with the higher subband channel utilization rate to transmit the service data to be transmitted.

[0049] Specifically, when the ground terminal detects from the received broadcast information that the channel utilization of the selectable target sub-bands has exceeded the second preset threshold, it means that the channel utilization of these sub-bands is high enough, and the system load at this rate is already relatively high, making it impossible to access new services. Therefore, the ground terminal will attempt to access services at the existing application layer load (corresponding to the rate). Based on the above, fill in some bytes (0x7E) to achieve the corresponding channel rate. Next, check if the channel utilization of the corresponding sub-band is available. If the channel utilization of the new target sub-band is lower than the second preset threshold, it is processed according to the random access method; if the channel utilization of the new target sub-band is higher than the second preset threshold, it means that the high-speed sub-band is also under high load. In this case, the terminal should postpone access to the system and select an appropriate method to send data in the next broadcast cycle.

[0050] In addition, when the satellite detects abnormal fluctuations in subband channel utilization, the corresponding radio resource management algorithm can trigger adjustments to the available frequency points of each rate subband and the channel utilization threshold for the next cycle to optimize the overall network performance.

[0051] The method of this invention can effectively improve the efficiency problem when a large number of terminals access the system and improve the effective utilization of system resources. It simplifies the signaling steps of low-orbit satellite Internet of Things and enhances the flexibility and applicability of the overall wireless resources of the constellation.

[0052] The data transmission system of the satellite Internet of Things provided by the present invention will be described below. The data transmission system of the satellite Internet of Things described below can be referred to in correspondence with the data transmission method of the satellite Internet of Things described above.

[0053] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the structure of a data transmission system for a satellite Internet of Things provided by the present invention.

[0054] This invention also provides a data transmission system for a satellite Internet of Things (IoT) applied to a ground terminal. The system includes: a utilization determination module 401, used to determine the frequency domain subband range and channel utilization of each service based on satellite broadcast information; a viewing module 402, used to view the subband channel utilization within the target range based on the length of the service data to be transmitted; and a transmission mode determination module 403, used to determine the access and transmission mode of the service data to be transmitted based on the subband channel utilization of the target range and a preset transmission threshold. The access and transmission mode includes a hybrid mode of direct data transmission, two-step random access, and reselection of transmission subband.

[0055] This invention utilizes periodic broadcast channel utilization information and subband partitioning information corresponding to different rate services, enabling ground terminals to access the system and send short message data using appropriate access methods. When the subband channel utilization of the target range is lower than a first preset threshold, the ground terminal can directly send uplink data on its channel without a random access procedure. When the subband channel utilization of the target range is between the first and second preset thresholds, the ground terminal needs to perform random access to obtain the radio resources allocated by the system before uploading data. When the subband channel utilization of the target range is higher than the second preset threshold, the ground terminal can choose to add padding bits to change the message length to query for occupied other subbands or postpone the transmission of the original information.

[0056] As a preferred embodiment, the satellite's broadcast information includes satellite identification information, available time-frequency resources for random access channels, sub-band channel utilization and utilization threshold values ​​for each service.

[0057] As a preferred embodiment, the sub-band channel utilization within the target range is viewed based on the length of the service data to be transmitted, including: determining the rate of the service data to be transmitted based on the length of the service data to be transmitted and the preset time slot length; and viewing the sub-band channel utilization within the rate range of the service data to be transmitted based on the rate of the service data to be transmitted.

[0058] As a preferred embodiment, the access and transmission method of the service data to be transmitted is determined based on the subband channel utilization rate of the target range and a preset transmission threshold, including: if there is a direct transmission channel utilization rate in the subband channel utilization rate of the target range, the service data to be transmitted is transmitted on the subband frequency point corresponding to the direct transmission channel utilization rate; the direct transmission channel utilization rate is lower than a first preset threshold value.

[0059] As a preferred embodiment, the access and transmission method for the service data to be transmitted is determined based on the sub-band channel utilization rate of the target range and the preset transmission threshold, including: when the sub-band channel utilization rate of the target range is higher than the first preset threshold and lower than the second preset threshold, a two-step random access method is adopted to send the uplink preamble and the amount of service data to be transmitted on the random access channel, obtain the time-frequency resource allocation and the maximum allowed number of transmissions, and transmit the service data to be transmitted on the allocated time-frequency resources.

[0060] As a preferred embodiment, the access and transmission method of the service data to be transmitted is determined based on the sub-band channel utilization rate of the target range and the preset transmission threshold, including: when the sub-band channel utilization rate of the target range is higher than the second preset threshold value, the length of the service data to be transmitted is adjusted by padding bits, and the service data to be transmitted is re-transmitted on the sub-band corresponding to the sub-band channel utilization rate of the next higher order rate.

[0061] Figure 5 An example is a schematic diagram of the structure of an electronic device, such as... Figure 5 As shown, the electronic device may include: a processor 501, a communications interface 502, a memory 503, and a communication bus 504. The processor 501, communications interface 502, and memory 503 communicate with each other via the communication bus 504. The processor 501 can call logical instructions in the memory 503 to execute a data transmission method for satellite IoT, applied to a ground terminal. The method includes: determining the frequency domain sub-band range and channel utilization of each service based on satellite broadcast information; checking the sub-band channel utilization within the target range based on the length of the service data to be transmitted; determining the access and transmission method for the service data to be transmitted based on the sub-band channel utilization within the target range and a preset transmission threshold; the access and transmission method includes a hybrid method of direct data transmission, two-step random access, and reselection of the transmission sub-band.

[0062] Furthermore, the logical instructions in the aforementioned memory 503 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a 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.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0063] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the data transmission method for satellite Internet of Things provided by the above methods, applied to a ground terminal. The method includes: determining the frequency domain sub-band range and channel utilization of each service based on satellite broadcast information; checking the sub-band channel utilization within the target range based on the length of the service data to be transmitted; determining the access transmission method for the service data to be transmitted based on the sub-band channel utilization within the target range and a preset transmission threshold; the access transmission method includes a hybrid method of direct data transmission, two-step random access, and reselection of transmission sub-band.

[0064] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the data transmission method for satellite Internet of Things provided by the above methods, applied to a ground terminal. The method includes: determining the frequency domain sub-band range and channel utilization of each service based on satellite broadcast information; checking the sub-band channel utilization within the target range based on the length of the service data to be transmitted; determining the access transmission method for the service data to be transmitted based on the sub-band channel utilization within the target range and a preset transmission threshold; the access transmission method includes a hybrid method of direct data transmission, two-step random access, and reselection of transmission sub-band.

[0065] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0066] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A data transmission method for a satellite Internet of Things, characterized in that, Applied to a ground terminal, the method includes: Based on the satellite broadcast information, determine the frequency domain subband range and channel utilization of each service; Based on the length of the service data to be transmitted, check the sub-band channel utilization within the target range; Based on the sub-band channel utilization rate of the target range and the preset transmission threshold, the access and transmission method for the service data to be transmitted is determined; the access and transmission method includes a hybrid method of direct data transmission, two-step random access, and reselection of transmission sub-band.

2. The data transmission method for satellite Internet of Things according to claim 1, characterized in that, The satellite's broadcast information includes satellite identification information, available time and frequency resources for random access channels, sub-band channel utilization rate and utilization threshold value for each service.

3. The data transmission method for satellite Internet of Things according to claim 1, characterized in that, The step of checking the sub-band channel utilization within the target range based on the length of the service data to be transmitted includes: The rate of the data to be transmitted is determined based on the length of the data to be transmitted and the preset time slot length. Based on the rate of the service data to be transmitted, check the sub-band channel utilization rate corresponding to the rate range of the service data to be transmitted.

4. The data transmission method for a satellite Internet of Things according to any one of claims 1 to 3, characterized in that, The step of determining the access and transmission method for the service data to be transmitted based on the sub-band channel utilization rate of the target range and a preset transmission threshold includes: If a direct transmission channel utilization rate exists within the subband channel utilization rate of the target range, the service data to be transmitted is transmitted on the subband frequency point corresponding to the direct transmission channel utilization rate; the direct transmission channel utilization rate is lower than a first preset threshold value.

5. The data transmission method for satellite Internet of Things according to claim 4, characterized in that, The step of determining the access and transmission method for the service data to be transmitted based on the sub-band channel utilization rate of the target range and a preset transmission threshold includes: When the utilization rate of the sub-band channels within the target range is higher than the first preset threshold and lower than the second preset threshold, a two-step random access method is adopted to send the uplink preamble and the amount of service data to be transmitted on the random access channel, obtain the time-frequency resource allocation and the maximum number of allowed transmissions, and transmit the service data to be transmitted on the allocated time-frequency resources.

6. The data transmission method for satellite Internet of Things according to claim 5, characterized in that, The step of determining the access and transmission method for the service data to be transmitted based on the sub-band channel utilization rate of the target range and a preset transmission threshold includes: If the subband channel utilization rate within the target range is higher than the second preset threshold, the length of the service data to be transmitted is adjusted by padding bits, and the service data to be transmitted is retransmitted on the subband corresponding to the subband channel utilization rate of a higher order rate.

7. A data transmission system for a satellite Internet of Things, characterized in that, The system, applied to ground terminals, includes: The utilization determination module is used to determine the frequency domain subband range and channel utilization of each service based on the satellite broadcast information; The viewing module is used to view the sub-band channel utilization within the target range based on the length of the service data to be transmitted. The transmission mode determination module is used to determine the access and transmission mode for the service data to be transmitted based on the sub-band channel utilization rate of the target range and the preset transmission threshold; the access and transmission mode includes a hybrid mode of direct data transmission, two-step random access, and reselection of transmission sub-band.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the data transmission method of the satellite Internet of Things as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the data transmission method of the satellite Internet of Things as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the data transmission method of the satellite Internet of Things as described in any one of claims 1 to 6.

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