Data transmission method, ground network element, terminal, satellite network element and storage medium

Abstract

The invention relates to a data transmission method, a ground network element, a terminal, a satellite network element and a storage medium. The method is applied to a ground MME (Mobility Management Entity), and comprises the following steps: according to satellite identifier monitoring list information which can be used for data transmission of a terminal, determining a next first satellite identifier which can reach the terminal first; and when the satellite feed link corresponding to the first satellite identifier is available, sending downlink data to a first on-satellite MME corresponding to the first satellite identifier.

Description

Technical Field

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

[0002] For low- and medium-Earth orbit (LEO) Internet of Things (IoT-NTN) technology, in the initial stages of network deployment, due to the limited number of satellites and gateway stations, the service links and power supply links of the satellites may not be available simultaneously. This can cause IoT-NTN to be unable to provide communication services to terminals within the satellite coverage area at times. To address this issue, the industry is researching IoT-NTN store-and-forward technology based on LEO satellite regeneration modes.

[0003] Currently, the IoT-NTN store-and-forward technology standard of 3GPP R19 (3rd Generation Partnership Project Release 19) has not yet been finalized, and some technical issues in various scenarios remain to be resolved. For example, in multi-satellite scenarios, how can terminals transmit uplink data via different satellites, and how can application downlink data be transmitted to user terminals via different satellites? Summary of the Invention

[0004] Therefore, it is necessary to provide a data transmission method, ground network element, terminal, satellite network element, and storage medium that can realize data transmission in multi-satellite scenarios to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a data transmission method applied to a terrestrial MME, the method comprising:

[0006] Based on the satellite identifier monitoring list information that the terminal can use for data transmission, determine the first satellite identifier that is most accessible to the terminal next;

[0007] When the satellite feed link corresponding to the first satellite identifier is available, downlink data is sent to the first onboard MME corresponding to the first satellite identifier.

[0008] Secondly, a data transmission method is provided, applied to SCEF or SGW, the method comprising:

[0009] Receive a storage instruction sent by the ground MME and store downlink data, wherein the storage instruction is used to indicate the storage of the downlink data;

[0010] The downlink data is sent to the ground MME.

[0011] Thirdly, a data transmission method is provided for application in SCS or AS, the method comprising:

[0012] Send downlink data to SCEF or SGW;

[0013] Waiting time for receiving confirmation messages for the downlink data sent by SCEF or SGW;

[0014] Start a first timer, wherein the time limit of the first timer is set based on the waiting time.

[0015] Fourthly, a data transmission method is provided, applied to a terminal, the method comprising:

[0016] Receive an SIB message, the SIB message including a second satellite identifier;

[0017] If the second satellite identifier is included in the satellite identifier listening list information available for data transmission by the terminal, then the uplink data will be sent to the second satellite corresponding to the second satellite identifier.

[0018] Fifthly, a data transmission method is provided, applied to the MME on a second satellite, the method comprising:

[0019] Receive uplink data sent by the terminal and save the uplink data;

[0020] When the satellite feed link corresponding to the MME on the second satellite is available, the uplink data is sent to the ground MME.

[0021] Sixthly, a ground-based MME is provided, comprising: a memory, a transceiver, and a processor.

[0022] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and execute the method as described in the first aspect.

[0023] Seventhly, an SCEF or SGW is provided, comprising: a memory, a transceiver, and a processor.

[0024] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and execute the method as described in the second aspect.

[0025] Eighthly, an SCS or AS is provided, comprising: a memory, a transceiver, and a processor.

[0026] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and execute the method as described in the third aspect.

[0027] Ninthly, a terminal is provided, comprising: a memory, a transceiver, and a processor.

[0028] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and execute the method as described in the fourth aspect.

[0029] Tenthly, a second-satellite on-board MME is provided, comprising: a memory, a transceiver, and a processor.

[0030] The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor; the processor is used to read the computer programs in the memory and execute the method as described in the fifth aspect.

[0031] Eleventhly, a ground-based MME is provided, comprising:

[0032] The determination module is used to determine the first satellite identifier that can be reached first from the terminal based on the satellite identifier monitoring list information that the terminal can use for data transmission.

[0033] The transmitting module is used to transmit downlink data to the first on-board MME corresponding to the first satellite identifier when the satellite feed link corresponding to the first satellite identifier is available.

[0034] In a twelfth aspect, an SCEF or SGW is provided, comprising:

[0035] A receiving module is configured to receive a storage instruction transmitted by a ground MME and store downlink data, wherein the storage instruction is used to indicate the storage of the downlink data;

[0036] The transmitting module is used to transmit the downlink data to the ground MME.

[0037] In a thirteenth aspect, an SCS or AS is provided, comprising:

[0038] The transmitting module is used to send downlink data to SCEF or SGW;

[0039] The receiving module is used to receive the confirmation message for the downlink data sent by SCEF or SGW and wait for the specified time.

[0040] A timing module is used to start a first timer, wherein the time limit of the first timer is set based on the waiting time.

[0041] Fourteenthly, a terminal is provided, comprising: a memory, a transceiver, and a processor.

[0042] A receiving module is used to receive SIB messages, wherein the SIB messages include a second satellite identifier;

[0043] The sending module is configured to send uplink data to the second satellite corresponding to the second satellite identifier if the satellite identifier listening list information available for data transmission by the terminal includes the second satellite identifier.

[0044] In a fifteenth aspect, a second-satellite on-board MME is provided, comprising: a memory, a transceiver, and a processor.

[0045] A receiving module is used to receive uplink data sent by the terminal and save the uplink data;

[0046] The transmitting module is used to transmit the uplink data to the ground MME when the satellite feed link corresponding to the MME on the second satellite is available.

[0047] In a sixteenth aspect, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, which, when executed by a processor, implements at least one of the following methods:

[0048] The methods described in the first aspect, the second aspect, the third aspect, the fourth aspect, and the fifth aspect.

[0049] In a seventeenth aspect, a computer program product is provided, the computer program product comprising a computer program that, when executed by a processor, implements at least one of the following methods:

[0050] The methods described in the first aspect, the second aspect, the third aspect, the fourth aspect, and the fifth aspect.

[0051] The aforementioned terrestrial MME, SCEF, SCS, AS, SGW, and PGW are all terrestrial network elements, while the MME on the first satellite and the MME on the second satellite are satellite network elements.

[0052] The aforementioned data transmission method allows the ground-based MME to determine the first satellite identifier of the next most reachable terminal based on the satellite identifier listening list information available for data transmission. When the feed link corresponding to the first satellite identifier is available, the ground-based MME sends downlink data to the MME on the first satellite corresponding to that identifier. Thus, in multi-satellite scenarios, the satellite for downlink transmission can be determined based on the satellite identifier listening list information, thereby enabling downlink transmission in multi-satellite scenarios.

[0053] In the aforementioned data transmission method, when the terminal determines that there is uplink data to be transmitted, it can obtain the second satellite identifier included in the SIB message by listening to the SIB message. Furthermore, if the second satellite identifier is included in the terminal's satellite identifier listening list information available for data transmission, the uplink data can be sent to the MME on the second satellite corresponding to the second satellite identifier. Thus, in a multi-satellite scenario, the satellite used for downlink transmission can be determined through the SIB message and the satellite identifier listening list information, thereby enabling uplink transmission in a multi-satellite scenario. Attached Figure Description

[0054] Figure 1 A flowchart illustrating a downlink data transmission method provided in an embodiment of this application;

[0055] Figure 2 This is a flowchart illustrating a non-IP type downlink data transmission method;

[0056] Figure 3 A flowchart illustrating a downlink data transmission method for IP type;

[0057] Figure 4 A flowchart illustrating an uplink data transmission method provided in an embodiment of this application;

[0058] Figure 5 This is a flowchart illustrating a non-IP type uplink data transmission method.

[0059] Figure 6 This is a flowchart illustrating an IP-type uplink data transmission method.

[0060] Figure 7 A schematic diagram of the structure of a communication device provided in one embodiment;

[0061] Figure 8 This is a structural block diagram of a ground-based MME;

[0062] Figure 9 This is a structural block diagram of an SCEF or SGW;

[0063] Figure 10 A structural block diagram of an SCS or AS;

[0064] Figure 11 This is a structural block diagram of a terminal.

[0065] Figure 12 This is a structural block diagram of an MME on a second satellite. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0067] In this embodiment of the invention, the term "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0068] Narrowband Internet of Things - Non-Terrestrial Network (IoT-NTN) is a Long Term Evolution (LTE) network mobile communication system that supports satellite access based on the Narrow Band Internet of Things (NB-IoT) technology standard. The satellite access method can be either satellite pass-through mode or satellite regeneration mode. This patent application relates to the satellite regeneration mode.

[0069] For IoT-NTN in satellite regeneration mode, the entire system consists of terminals, satellite regeneration payloads (such as evolved Node Bs (eNodeBs), Mobility Management Entities (MMEs), Serving Gateways (SGWs), satellite gateways, core networks, and service servers). Depending on the network configuration, the functions included in the satellite regeneration payloads may vary; they may possess the functions of both evolved Node Bs (eNodeBs) and Mobility Management Entities (MMEs). This system focuses on supporting satellite IoT services for low-complexity enhanced Machine Type Communication (eMTC) and IoT terminals, primarily targeting scenarios such as maritime transport, energy harvesting, global asset tracking, and environmental monitoring, providing reliable data transmission services for various low-data-rate, low-frequency, and low-cost IoT applications.

[0070] For IoT-NTN technology in low and medium orbit, in the early stages of network construction, due to the limited number of satellites and gateway stations, there are situations where the satellite service link and power supply link cannot be available at the same time. This results in IoT-NTN being unable to provide communication services to terminals within the satellite coverage area at certain times.

[0071] To address this situation, the industry is researching IoT-NTN store-and-forward technology based on low- and medium-Earth orbit satellite regeneration mode. The basic technical idea is as follows: when the service link is available but the power supply link is unavailable, the satellite network element can communicate with the terminal, receive messages sent by terminals within its coverage area, cache them in the satellite network element, and forward cached messages from the terrestrial network to the terminal. When the power supply link is available but the service link is unavailable, the satellite network element can communicate with the terrestrial network through a gateway station, transmit the cached terminal messages back to the ground, and receive messages sent to the terminal from the terrestrial network, cached in the satellite network element. This technology can be widely applied in IoT scenarios with non-real-time communication requirements.

[0072] Currently, the IoT-NTN store-and-forward technology standard of the 3rd Generation Partnership Project (3GPP) R19 has not yet been finalized, and related solutions are still in the research stage. There are still some technical issues to be resolved in some scenarios, such as how terminals can send uplink data through different satellites in multi-satellite scenarios, and how application downlink data can be sent to user terminals through different satellites, so as to achieve load balancing of different satellites or different satellites serving different IoT-NTN applications.

[0073] To address the aforementioned issues, this application proposes a data transmission method applicable to single-satellite or multi-satellite scenarios. When a terminal needs to send uplink data, it listens for satellite signals listed in the satellite identifier listening list and then sends the uplink data. When the network-side device needs to send downlink data to the terminal, it can perform corresponding downlink data transmission based on the satellite identifier listening list information available for data transmission at the terminal. This solution enables uplink and downlink data transmission in single-satellite or multi-satellite scenarios and achieves load balancing among different store-and-forward satellites, as well as energy saving for the terminal.

[0074] The relevant functional network elements involved in this application embodiment include:

[0075] 1) Terminal: Supports network access and data transmission functions in non-terrestrial network (NTN) store-and-forward scenarios.

[0076] 2) Onboard Mobility Management Entity (MME): Located on the satellite, the MME is a subset of the MME's functions, including receiving and forwarding NAS signaling / data messages, and caching Non-Access Stratum (NAS) signaling / data messages. When the serving link is available, it receives and caches uplink NAS signaling / data messages from the terminal and forwards the cached downlink NAS signaling / data messages to the terminal. When the power supply link is available, it forwards the cached uplink NAS signaling / data messages to the ground-based MME and receives and caches downlink NAS signaling / data messages from the ground-based MME.

[0077] 3) Ground Mobility Management Function Entity (Ground MME): Located on the ground, this mobility management function entity possesses all the functions of a mobility management function entity, responsible for terminal mobility management, access control, bearer management, session management, and NAS signaling processing. It has the function of determining downlink data routing based on terminal location information and a list of available satellite identity (ID) information for terminal data transmission, as well as the function of synchronizing user equipment (UE) context information with the onboard MME. In an MME-separated architecture, the ground MME also functions as a ground anchor network element.

[0078] 4) SCEF Functional Entity: An abbreviation for Service Capability Exposure Function, which has monitoring capabilities. Functions include device status monitoring and forwarding non-Internet Protocol (non-IP) data.

[0079] 5) SCS functional entity: Service Capability Server.

[0080] 6) AS functional entity: Application Server.

[0081] 7) SGW: Serving Gateway. The SGW is responsible for routing and forwarding user plane data. It is a key network element in the core network connecting eNodeBs (base stations) and Packet Data Network Gateways (PDN Gateways, PGWs). The SGW can handle handover between different base stations, ensuring the continuity of user data during movement. For example, when a user moves from the coverage area of ​​one base station to the coverage area of ​​another, the SGW is responsible for switching the user's data transmission path to ensure uninterrupted data transmission.

[0082] 8) PGW: Packet Data Network Gateway. A PGW is a gateway connecting external data networks (such as the Internet) and the mobile core network. It is responsible for assigning IP addresses to users, performing billing and policy control, and executing functions such as packet filtering and deep packet inspection. For example, when a user accesses the Internet, the PGW controls data traffic and billing based on the user's data plan and network policies, and ensures secure data transmission.

[0083] The data transmission methods provided in this application include an uplink data transmission method and a downlink data transmission method, which are described below.

[0084] For example, Figure 1 This is a flowchart illustrating a downlink data transmission method provided in an embodiment of this application. The method may include, but is not limited to, the following steps:

[0085] Step S11: The ground MME determines the first satellite identifier of the next most reachable terminal based on the satellite identifier listening list information that the terminal can use for data transmission.

[0086] The first satellite identifier of the next most reachable terminal refers to the identifier of the satellite that will be able to establish a valid communication connection with the terminal first among a series of satellites that can be used to transmit data with the terminal.

[0087] In some embodiments, the ground-based MME can determine the first satellite identifier of the next most reachable terminal based on the terminal's location information and the satellite identifier listening list information that the terminal can use for data transmission.

[0088] Since the location information of the terminal may change, the determination of the first satellite identifier of the next most reachable terminal takes into account the location change of the terminal, based on the location information of the terminal and the satellite identifier listening list information that the terminal can use for data transmission, so that the first satellite identifier of the next most reachable terminal is more accurate.

[0089] In some embodiments, a satellite identifier listening list information that the terminal can use for data transmission can be determined based on the first information. The first information includes at least one of the following:

[0090] Terminal subscription data, satellite ephemeris information, terminal location information, and MME default configuration information.

[0091] The subscription data of the aforementioned terminal is related to the service package, permissions, priority, and other information subscribed by the terminal user. For example, it may include whether the user has subscribed to high-speed or low-speed data service, or whether they have access to specific satellites.

[0092] The satellite ephemeris information described above contains detailed spatiotemporal parameters such as the satellite's orbit, position, speed, and transit time, which helps to predict the satellite's position and coverage area at different times.

[0093] The location information of the terminal mentioned above refers to the current geographical location of the terminal, which is very important for determining which satellite can provide the first coverage and establish a connection with it.

[0094] The above-mentioned MME default configuration information consists of some default configuration parameters pre-set by the MME. Examples include default satellite selection strategies and priority rules.

[0095] For example, if a terminal's location information indicates that it is moving rapidly, combining this with satellite ephemeris information can more accurately determine which satellite will arrive at its location first and provide service. The terminal's subscription data may determine which satellites it can use. MME default configuration information may specify the preferred type of satellite in certain situations.

[0096] Step S12: When the satellite feed link corresponding to the first satellite identifier is available, the ground MME sends downlink data to the on-board MME corresponding to the first satellite identifier.

[0097] The MME on the first satellite mentioned above is a satellite network element.

[0098] The satellite feed link corresponding to the first satellite identifier is the link between the ground MME and the on-board MME of the first satellite. The on-board MME of the first satellite can be the MME deployed on the first satellite corresponding to the first satellite identifier.

[0099] The aforementioned data transmission method allows the ground-based MME to determine the first satellite identifier of the next most reachable terminal based on the satellite identifier listening list information available for data transmission. When the feed link corresponding to the first satellite identifier is available, the ground-based MME sends downlink data to the MME on the first satellite corresponding to that identifier. Thus, in multi-satellite scenarios, the satellite for downlink transmission can be determined based on the satellite identifier listening list information, enabling downlink transmission in single-satellite or multi-satellite scenarios.

[0100] In this application embodiment, the downlink data transmission method involves both non-Internet Protocol (non-IP) and Internet Protocol (IP) type downlink data transmission methods. To more clearly illustrate the downlink data transmission methods in this application embodiment, the following descriptions of the non-IP type and the IP type downlink data transmission methods are provided respectively.

[0101] (1) Downlink data transmission method for non-IP type.

[0102] In some embodiments, when the satellite feed link corresponding to the first satellite identifier is available, the ground MME can send a downlink data transmission instruction to the SCEF, receive downlink data sent by the SCEF, and send downlink data to the MME on the first satellite.

[0103] In some embodiments, before sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, the ground MME may receive downlink data sent by the SCEF through the Service Capability Server (SCS). The ground MME may also determine the waiting time for the SCS to receive an acknowledgment message for the downlink data; and send the waiting time to the SCS through the SCEF.

[0104] In other words, the SCS will send downlink data to the SCEF. After the SCEF receives the downlink data sent by the SCS, the SCEF can send the downlink data to the ground MME.

[0105] In some embodiments, before sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, the ground MME may receive downlink data sent by the SCEF through the Application Server (AS). The ground MME may also determine the waiting time for the AS to receive an acknowledgment message for the downlink data; and send the waiting time to the AS through the SCEF.

[0106] In other words, the AS will send downlink data to the SCEF, and after the SCEF receives the downlink data sent by the AS, the SCEF can send the downlink data to the ground MME.

[0107] The ground-based MME can estimate the waiting time for the SCS or AS to receive an acknowledgment message after transmitting downlink data, and will inform the SCS or AS of this time. The ground-based MME can then send the waiting timeline to the SCEF, which will then forward it to the SCS or AS.

[0108] In some embodiments, after receiving the aforementioned waiting time, the SCS or AS may start a first timer, wherein the duration of the first timer is set based on the waiting time. For example, the implementation of the first timer may be set to be equal to the aforementioned waiting time.

[0109] In some embodiments, if no acknowledgment message is received when the first timer expires, it indicates that the downlink data transmission may have failed. In this case, the downlink data is resent to the SCEF or SGW. If an acknowledgment message is received within the time limit of the first timer, it indicates that the downlink data transmission has been successful. In this case, the first timer can be cancelled.

[0110] In some embodiments, before the ground MME sends downlink data to the on-board MME corresponding to the first satellite identifier, the downlink data can be saved if the satellite feed link corresponding to the first satellite identifier is unavailable. Since the satellite feed link corresponding to the first satellite identifier is currently unavailable, it is necessary to wait until the satellite feed link corresponding to the first satellite identifier becomes available before sending downlink data; therefore, it is necessary to save the downlink data first.

[0111] In some embodiments, if the ground MME does not have data storage capabilities, or if the storage space is insufficient to store downlink data, the ground MME sends a storage instruction to the SCEF. This storage instruction instructs the SCEF to store the downlink data. In other words, when the ground MME is unable to store downlink data, a storage instruction can be used to instruct the SCEF to store the downlink data.

[0112] In some embodiments, the SCEF can receive a storage instruction sent by the ground MME and store downlink data. Furthermore, when the satellite feed link corresponding to the first satellite identifier is available, the ground MME can obtain downlink data from the SCEF, and the SCEF can send downlink data to the ground MME.

[0113] In some embodiments, when the satellite feed link corresponding to the first satellite identifier is available, a downlink data transmission instruction is sent to the SCEF; downlink data sent by the SCEF is received, and downlink data is sent to the MME on the first satellite.

[0114] In some embodiments, after the SCEF sends downlink data to the ground MME, the SCEF may delete the stored downlink data.

[0115] For example, Figure 2 This is a flowchart illustrating a non-IP type downlink data transmission method, as shown below. Figure 2 As shown, the method includes, but is not limited to, the following steps:

[0116] Step S101: The terminal sends an attach request message to the ground MME.

[0117] In some embodiments, step S101 above can also be replaced by the terminal sending a TAU request message to the ground MME.

[0118] Step S102: The ground MME determines the satellite identifier listening list information that the terminal can use for data transmission based on the first information.

[0119] The first piece of information includes at least one of the following:

[0120] Terminal subscription data, satellite ephemeris information, terminal location information, and MME default configuration information.

[0121] In some embodiments, after receiving the attach request message, the ground MME can determine the satellite identifier listening list information based on the above step S102 after the necessary authentication process.

[0122] Among them, the satellite identification listening list information is the list of satellite IDs that the listening terminal can use during data transmission.

[0123] Step S103: The ground MME sends an attach receive message to the terminal, which carries satellite identification listening list information that the terminal can use for data transmission.

[0124] In some embodiments, if step S101 is replaced by the terminal sending a TAU request message to the ground MME, step S103 can be replaced by the ground MME sending a TAU acceptance message to the terminal, the TAU acceptance message carrying satellite identifier listening list information that the terminal can use for data transmission.

[0125] Step S104: The terminal saves the satellite identifier listening list information that the terminal can use for data transmission.

[0126] Step S105: When the power supply link is available, the ground MME sequentially synchronizes the terminal context information to the on-board MMEs within the range indicated by the satellite identifier listening list information.

[0127] Step S201: SCS / AS sends downlink data to SCEF via a Non-IP Data Delivery Submit Request (NIDD) message.

[0128] The aforementioned SCS / AS refers to terrestrial network elements.

[0129] SCS / AS can send an NIDD Submit Request message to SCEF, which carries downlink data.

[0130] In step S202, after SCEF performs necessary authentication and policy control, it forwards the NIDD Submit Request message to the ground MME.

[0131] The SCEF mentioned above refers to terrestrial network elements.

[0132] Step S203: The ground MME determines the next satellite ID that can reach the terminal first based on the terminal's location information and the satellite identifier listening list information that the terminal can use for data transmission, and estimates the waiting time for the SCS or AS to receive the confirmation message for downlink data.

[0133] If the ground MME has a data caching function, or if the ground MME has sufficient data storage space, the following steps S204a to S207a can be executed; if the ground MME does not have a data caching function, or if the ground MME has insufficient data caching space, the following steps S204b to S210b can be executed.

[0134] In step S204a, the ground MME returns a Non-IP Data Delivery Submit Response (NIDD Submit Response) message to the SCEF, carrying the estimated waiting time.

[0135] Step S205a: SCEF forwards the NIDD Submit Response message to SCS / AS.

[0136] Step S206a: Start the SCS / AS timer.

[0137] The timer's duration can be set based on the aforementioned waiting time.

[0138] If no acknowledgment message for downlink data is received within the timer's time limit, the SCS / AS will not resend downlink data to the SCEF. If the timer expires and no acknowledgment message for downlink data is received, the SCS / AS will resend the downlink data to the SCEF. If an acknowledgment message for downlink data is received within the timer's time limit, the SCS / AS will stop the timer.

[0139] Step S207a: The ground MME saves the downlink data.

[0140] In step S204b, the ground MME returns an NIDD Submit Response message to the ground SCEF, along with a cache indication and an estimated waiting time.

[0141] Step S205b, SCEF saves the downlink data.

[0142] Once SCEF receives the cache instruction, it can save the downlink data.

[0143] Step S206b: Send an NIDD Submit Response message to SCS / AS, carrying the estimated waiting time.

[0144] In step S207b, after receiving the message, the SCS / AS starts the timer.

[0145] The descriptions of steps S206b and S207b above can be found in the descriptions of S204a and S206a, and will not be repeated here.

[0146] In step S208b, when the satellite feed link for the satellite ID determined by the ground MME is available, the ground MME sends a Non-IP Data Delivery Submit Indication (NIDD) message to the SCEF.

[0147] The NIDD Submit Indication message indicates that downlink data can be sent.

[0148] In step S209b, SCEF sends an NIDD Submit Request message containing downlink data to the ground MME.

[0149] Step S210b, SCEF deletes downlink data.

[0150] After performing steps S204a to S207a, the following step S211 can be performed; or, after performing steps S204b to S210b, the following step S211 can be performed.

[0151] Step S211: The ground MME sends downlink data to the satellite MME.

[0152] Step S212: The onboard MME returns a downlink data reception acknowledgment (ACK) to the ground MME.

[0153] Step S213: The ground MME deletes downlink data.

[0154] It should be noted that step S213 is performed after steps S204a to S207a have been executed. In other words, step S213 is for cases where the ground MME has a data caching function or the ground MME has sufficient data storage space.

[0155] Step S213: The onboard MME saves the downlink data and determines the estimated time for the downlink data to arrive at the terminal based on the terminal's location information and ephemeris information.

[0156] Step S214: When the terminal is within the coverage area of ​​the satellite indicated by the satellite ID and the service link is available, the on-board MME pages the terminal through the on-board base station (eNodeB).

[0157] Step S215: The onboard MME establishes / restores a connection with the terminal.

[0158] Among them, establishing / restoring the connection between the onboard MME and the terminal can refer to establishing or restoring the Radio Resource Control (RRC) connection.

[0159] Step S216: The onboard MME sends the saved downlink data to the terminal.

[0160] Step S217: The onboard MME deletes the saved downlink data.

[0161] Step S218: When the satellite feed link where the onboard MME is located is available, the onboard MME sends a downlink data confirmation message to the ground MME via the NIDD SubmitResponse message.

[0162] The NIDD Submit Response message includes confirmation messages for the downlink data.

[0163] Step S219: The ground MME forwards the NIDD Submit Response message to the SCEF.

[0164] Step S220: The ground SCEF forwards the NIDD Submit Response message to the SCS / AS.

[0165] Step S221: SCS receives the NIDD Submit Response message and stops the timer.

[0166] If the SCS receives an NIDD SubmitResponse message carrying downlink data confirmation within the timer's time limit, the timer can be stopped.

[0167] The above embodiments provide a non-IP type downlink data transmission method. In multi-satellite scenarios, this method can determine the satellites used for downlink transmission based on satellite identifier listening list information, thereby achieving downlink transmission in single-satellite or multi-satellite scenarios. It can achieve load balancing among different store-and-forward satellites and power saving at the terminal.

[0168] (2) Downlink data transmission method for IP type.

[0169] In some embodiments, the terrestrial MME can also receive downlink data notifications sent by the SGW, which indicate that downlink data transmission is required. The terrestrial MME can send a downlink data notification acknowledgment message to the SGW.

[0170] In some embodiments, if the ground MME does not have data storage capabilities, or if the storage space is insufficient to store downlink data, the downlink data notification confirmation message sent to the SGW may include a storage indication; wherein the storage indication is used to indicate the storage of downlink data.

[0171] In other words, when the terrestrial MME does not have data storage capabilities, or when the storage space is insufficient to store downlink data, the terrestrial MME can use storage instructions to allow the SGW to store downlink data.

[0172] In some embodiments, when the ground MME instructs the SGW to store downlink data via a storage instruction, the ground MME can obtain downlink data from the SGW and send the downlink data to the MME on the first satellite when the satellite feed link corresponding to the first satellite identifier is available.

[0173] In some embodiments, when the satellite feed link corresponding to the first satellite identifier is unavailable, the ground MME can receive downlink data sent by the SGW and save the downlink data. Then, when the satellite feed link corresponding to the first satellite identifier becomes available, it can send downlink data to the first onboard MME corresponding to the first satellite identifier.

[0174] In some embodiments, for cases where the ground MME stores downlink data, the ground MME can delete the downlink data after sending it to the MME on the first satellite corresponding to the first satellite identifier.

[0175] For example, Figure 3 This is a flowchart illustrating a downlink data transmission method for IP type, such as... Figure 3 As shown, the method includes, but is not limited to, the following steps:

[0176] In step S300, the SGW receives the downlink data sent by the PGW.

[0177] It should be noted that, before performing step S300 above, the following can also be performed: Figure 2 Steps S101 to S105 are shown.

[0178] Step S301: The ground MME receives the downlink data notification from the SGW.

[0179] If the ground MME has a data caching function, or if the ground MME has sufficient data storage space, the following steps S302a to S306a can be executed; if the ground MME does not have a data caching function, or if the ground MME has insufficient data caching space, the following steps S304b to S307b can be executed.

[0180] The aforementioned downlink data notification is used to notify terrestrial network elements that there is downlink data to transmit.

[0181] Step S302a: The ground MME sends a downlink data notification ACK to the SGW.

[0182] Step S303a: The ground MME obtains the downlink data from the SGW and saves the downlink data.

[0183] Among them, the ground MME can update the bearer channel, that is, update the bearer channel between the ground MME and the SGW, and receive downlink data sent by the SGW.

[0184] When the ground MME has a data caching function, or when the ground MME has sufficient data storage space, the ground network element MME obtains the downlink data from the SGW and saves the downlink data.

[0185] In step S304a, the ground MME determines the next satellite ID that can reach the terminal in the shortest possible time based on the terminal's location information, the satellite identifier listening list information that the terminal can use for data transmission, and the ephemeris information.

[0186] Step S305a: When the feed link of the satellite corresponding to the satellite ID is available, the ground MME sends downlink data to the onboard MME corresponding to the satellite ID.

[0187] Step S306a: The ground MME deletes downlink data.

[0188] After performing step S306a, step S308 can be performed.

[0189] In step S302b, the ground MME determines the next satellite ID that can reach the terminal in the shortest time based on the terminal's location information, the satellite identifier listening list information that the terminal can use for data transmission, and the ephemeris information, and estimates the downlink data storage time in the SGW.

[0190] In step S303b, the ground MME sends a downlink data notification ACK to the SGW, carrying a storage indication.

[0191] Step S304b: SGW saves downlink data.

[0192] In step S305b, when the satellite feed link for the satellite ID is available, the ground MME obtains the downlink data of the UE from the SGW.

[0193] When the satellite feed link for this satellite ID is available, the ground MME can update the bearer channel and receive downlink data sent by the SGW.

[0194] Step S306b: SGW deletes cached downlink data.

[0195] Step S307b: The ground MME sends downlink data to the onboard MME corresponding to the satellite ID.

[0196] Step S308: The onboard MME saves the downlink data;

[0197] Step S309: When the terminal is within the coverage area of ​​the satellite indicated by the satellite ID and the service link is available, the terminal is paged by the on-board base station.

[0198] Step S310: The onboard MME establishes a connection with the terminal.

[0199] Step S311: The onboard MME sends the saved downlink data to the terminal via NAS message.

[0200] Step S312: The onboard MME deletes the saved downlink data.

[0201] After receiving the Non-Access Stratum Delivery Notification (NAS Delivery Notification) message from the onboard base station, the onboard MME knows that the downlink data has been successfully sent to the terminal, and can then delete the saved downlink data.

[0202] Furthermore, when the satellite feed link corresponding to the satellite ID is available, the onboard MME can forward the NAS DeliveryNotification message to the ground MME to inform the MME that the downlink data has been successfully sent to the terminal.

[0203] The above embodiments provide a downlink data transmission method for IP type. In multi-satellite scenarios, this method can determine the satellite used for downlink transmission based on satellite identifier listening list information, thereby realizing downlink transmission in single-satellite or multi-satellite scenarios. It can achieve load balancing among different store-and-forward satellites and energy saving in terminals.

[0204] For example, Figure 4This is a flowchart illustrating an uplink data transmission method provided in an embodiment of this application. The method may include, but is not limited to, the following steps:

[0205] S41. When the terminal determines that there is uplink data to be transmitted, it listens for SIB messages, which include the second satellite identifier.

[0206] S42. If the satellite identifier listening list information available for data transmission by the terminal includes a second satellite identifier, the terminal will send uplink data to the MME on the second satellite corresponding to the second satellite identifier.

[0207] If the satellite identifier listening list information available for data transmission by the terminal includes a second satellite identifier, the terminal can establish a connection with the MME on the second satellite and send uplink data to the MME on the second satellite corresponding to the second satellite identifier.

[0208] In some embodiments, the terminal may also send indication information to the second satellite corresponding to the second satellite identifier. The indication information is used to indicate that downlink data transmission exists after uplink data transmission. Sending the indication information to the second satellite may mean sending the indication information to the on-board base station on the second satellite, and then to the on-board MME on the second satellite, i.e., the aforementioned second on-board MME.

[0209] In some embodiments, the terminal may also receive the arrival time of downlink data transmitted by the MME on the second satellite of the second satellite and start a second timer, wherein the duration of the second timer is set based on the arrival time of the downlink data.

[0210] In some embodiments, when the second timer expires, if the service link is available, the system listens for paging messages and prepares to receive downlink data.

[0211] S43, the MME on the second satellite stores the uplink data.

[0212] S44. When the satellite feed link corresponding to the MME on the second satellite is available, the MME on the second satellite sends uplink data to the ground MME.

[0213] In some embodiments, after the MME on the second satellite sends uplink data to the ground MME, the MME on the second satellite can delete the uplink data.

[0214] In some embodiments, the MME on the second satellite can receive indication information sent by the terminal, which indicates that downlink data transmission exists after uplink data transmission; the MME on the second satellite can determine the arrival time of the downlink data based on the terminal's location information and ephemeris information, and send the arrival time of the downlink data to the terminal.

[0215] In some embodiments, the MME on the second satellite can receive downlink data transmitted by the ground MME and store the downlink data. When the service link is available, if the terminal is within the coverage area of ​​the MME on the second satellite, a paging message is sent to the terminal to establish a connection with the terminal, and downlink data is sent to the terminal.

[0216] In the aforementioned data transmission method, when the terminal determines that there is uplink data to be transmitted, it can obtain the second satellite identifier included in the SIB message by listening to the SIB message. Furthermore, if the second satellite identifier is included in the terminal's satellite identifier listening list information available for data transmission, the uplink data can be sent to the MME on the second satellite corresponding to the second satellite identifier. Thus, in multi-satellite scenarios, the satellite used for downlink transmission can be determined through the SIB message and the satellite identifier listening list information, thereby enabling uplink transmission in single-satellite or multi-satellite scenarios.

[0217] In this application embodiment, the uplink data transmission method involves both non-Internet Protocol (non-IP) type uplink data transmission methods and Internet Protocol (IP) type uplink data transmission methods. To more clearly illustrate the uplink data transmission methods in this application embodiment, the non-IP type uplink data transmission method and the IP type uplink data transmission method are described above respectively.

[0218] For example, Figure 5 This is a flowchart illustrating a non-IP type uplink data transmission method, such as... Figure 5 As shown, the method includes, but is not limited to, the following steps:

[0219] S501. Based on application or user instructions, when the terminal determines that there is uplink data to be sent and the service link is available, it receives an SIB message and determines that the satellite ID in the SIB message belongs to the satellite identifier listening list information that the terminal can use for data transmission.

[0220] The terminal is in the Evolved Packet Core Mobility Management Connected State (ECM) idle state.

[0221] S502, The terminal establishes a connection with the satellite base station and the satellite MME.

[0222] S503: The terminal sends uplink data to the onboard MME via NAS messages.

[0223] S504, the onboard MME determines whether the message carries information indicating that there is downlink data transmission after uplink data transmission.

[0224] The downlink data can be an acknowledgment message for receiving uplink data, such as an uplink acknowledgment (UL ACK) or an uplink response (UL response).

[0225] If so, the onboard MME determines the possible arrival time of the downlink data based on the terminal location information and ephemeris information, executes steps S505, S506 and S507 and then executes step S508; if not, steps S505, S506 and S507 are not executed, and step S508 is executed.

[0226] The S505 and onboard MME notify the terminal of the arrival time of downlink data via NAS messages.

[0227] S506, Terminal Startup Timer.

[0228] The timer's duration is set based on the arrival time of the downlink data.

[0229] S507. If the timer expires and the service link is available, actively listen for paging and prepare to receive downlink data.

[0230] S508, the onboard MME stores uplink data.

[0231] S509 and the satellite base station detected no further link messages and released the RRC connection and S1-MME connection respectively.

[0232] Specifically, releasing the RRC connection and the S1-MME connection can be achieved by releasing the RRC connection between the satellite base station and the terminal, and releasing the S1-MME connection between the satellite base station and the satellite MME.

[0233] S510. When the satellite's power supply link is available, the onboard MME forwards uplink data to the ground MME.

[0234] S511, the ground MME returns the uplink data reception ACK message to the satellite MME.

[0235] S512, the onboard MME deletes the saved uplink data.

[0236] After the onboard MME receives the uplink data reception ACK message, it can know that the uplink data has been successfully transmitted, and at this time the saved uplink data can be deleted.

[0237] S513, the ground MME sends an NIDD Submit Request containing uplink data to the ground network element SCEF.

[0238] S514, SCEF sends an NIDD Submit Indication message containing uplink data to SCS / AS.

[0239] S515 and SCS / AS send an NIDD Submit Response message to the ground network element SCEF to confirm receipt of uplink data.

[0240] S516, SCEF forwards the NIDD Submit Response message acknowledging receipt of uplink data to the ground MME.

[0241] The aforementioned non-IP uplink data transmission method, in multi-satellite scenarios, can identify the satellite used for downlink transmission through SIB messages and satellite identifier listening list information, thereby achieving uplink transmission in single-satellite or multi-satellite scenarios. It can also achieve load balancing among different store-and-forward satellites and power saving at the terminal.

[0242] For example, Figure 6 This is a flowchart illustrating an IP-type uplink data transmission method, such as... Figure 6 As shown, the method may include, for example: Figure 5 The steps S501 to S510 shown are illustrated, and the steps following step S501 may include, but are not limited to, the following steps:

[0243] S601, the onboard MME deletes the saved uplink data.

[0244] S602, Ground MME Update Bearer Channel.

[0245] S603, the ground MME sends uplink data to the SGW.

[0246] S604 and SGW forward uplink data to PGW.

[0247] Among them, PGW can forward uplink data to SCS / AS.

[0248] The aforementioned IP-based uplink data transmission method, in multi-satellite scenarios, can identify the satellite used for downlink transmission through SIB messages and satellite identifier listening list information, thereby enabling uplink transmission in single-satellite or multi-satellite scenarios. It can also achieve load balancing among different store-and-forward satellites and energy saving at the terminal.

[0249] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0250] Based on the same technical concept, this application also provides a communication device. This communication device can implement one or more of the functions of MME, SCEF, SGW, SCS, AS, terminal, and MME on a second satellite as described in the foregoing embodiments.

[0251] For example, Figure 7 This is a schematic diagram of a communication device provided in one embodiment. The communication device includes: a memory 701, a transceiver 702, and a processor 703, wherein the memory 701, transceiver 702, and processor 703 are connected via a bus interface.

[0252] The memory 701 is used to store computer programs; the transceiver 702 is used to send and receive data under the control of the processor 703.

[0253] Regarding the case where the communication equipment is a terrestrial MME:

[0254] The processor 703 described above is used to read the computer program in the memory 701 and perform the following operations:

[0255] Based on the satellite identifier monitoring list information that the terminal can use for data transmission, determine the first satellite identifier that is most accessible to the terminal next;

[0256] When the satellite feed link corresponding to the first satellite identifier is available, downlink data is sent to the first onboard MME corresponding to the first satellite identifier.

[0257] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0258] Receive the downlink data sent by SCEF via SCS or AS;

[0259] Determine the waiting time for the SCS or AS to receive an acknowledgment message for the downlink data;

[0260] The waiting time is sent to the SCS or AS via the SCEF.

[0261] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0262] Before sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, the downlink data is saved when the satellite feed link corresponding to the first satellite identifier is unavailable.

[0263] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0264] If the ground MME does not have data storage function, or if the storage space is insufficient to store the downlink data, a storage instruction is sent to the SCEF, the storage instruction being used to instruct the storage of the downlink data.

[0265] In some embodiments, the processor 703 described above is specifically configured to read the computer program in the memory 701 and perform the following operations:

[0266] When the satellite feed link corresponding to the first satellite identifier is available, a downlink data transmission instruction is sent to the SCEF.

[0267] The system receives the downlink data sent by the SCEF and sends the downlink data to the MME on the first satellite.

[0268] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0269] Receive downlink data notification sent by SGW, the downlink data notification being used to indicate that downlink data transmission is required;

[0270] Send a downlink data notification confirmation message to the SGW.

[0271] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0272] If the ground MME does not have data storage function, or if the storage space is insufficient to store the downlink data, the downlink data notification confirmation message includes a storage instruction;

[0273] The storage indication is used to indicate the storage of the downlink data.

[0274] In some embodiments, the processor 703 described above is specifically configured to read the computer program in the memory 701 and perform the following operations:

[0275] When the satellite feed link corresponding to the first satellite identifier is available, the downlink data is obtained from the SGW and sent to the MME on the first satellite.

[0276] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0277] Before sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, if the satellite feed link corresponding to the first satellite identifier is unavailable, the downlink data sent by the SGW is received and the downlink data is saved.

[0278] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0279] After sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, the downlink data is deleted.

[0280] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0281] Based on the first information, determine the satellite identifier monitoring list information that the terminal can use for data transmission;

[0282] The first information includes at least one of the following:

[0283] The terminal's subscription data, satellite ephemeris information, terminal's location information, and MME default configuration information.

[0284] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0285] Send the satellite identifier monitoring list information that the terminal can use for data transmission to the terminal;

[0286] And / or,

[0287] The terminal's context information is sent to the onboard MME corresponding to the range indicated by the satellite identifier listening list information.

[0288] In some embodiments, the processor 703 described above is specifically configured to read the computer program in the memory 701 and perform the following operations:

[0289] Based on the terminal's location information and the satellite identifier monitoring list information that the terminal can use for data transmission, the first satellite identifier that can reach the terminal first is determined.

[0290] For cases where the communication device is SCEF or SGW:

[0291] The processor 703 described above is used to read the computer program in the memory 701 and perform the following operations:

[0292] Receive a storage instruction sent by the ground MME and store downlink data, wherein the storage instruction is used to indicate the storage of the downlink data;

[0293] The downlink data is sent to the ground MME.

[0294] In some embodiments, when the communication device is SCEF, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0295] Receive the downlink data sent by SCS or AS;

[0296] The downlink data is sent to the ground MME;

[0297] The system receives the confirmation message for the downlink data sent by the ground MME and sends the waiting time to the SCS or the AS.

[0298] In some embodiments, when the communication device is an SGW, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0299] Send a downlink data notification to the ground MME, the downlink data notification indicating that downlink data transmission is required;

[0300] The processor 703 described above is specifically used to read the computer program in the memory 701 and perform the following operations:

[0301] Receive a downlink data notification confirmation message sent by the ground MME, the downlink data notification confirmation message including the storage indication.

[0302] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0303] After sending the downlink data to the ground MME, the downlink data is deleted.

[0304] For cases where the communication device is an SCS or AS:

[0305] The processor 703 described above is used to read the computer program in the memory 701 and perform the following operations:

[0306] Send downlink data to SCEF or SGW;

[0307] Waiting time for receiving confirmation messages for the downlink data sent by SCEF or SGW;

[0308] Start a first timer, wherein the time limit of the first timer is set based on the waiting time.

[0309] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0310] If the acknowledgment message is not received when the first timer expires, the downlink data is retransmitted to SCEF or SGW;

[0311] If the confirmation message is received within the time limit of the first timer, the first timer is cancelled.

[0312] For cases where the communication device is a terminal:

[0313] The processor 703 described above is used to read the computer program in the memory 701 and perform the following operations:

[0314] When it is determined that there is uplink data to be transmitted, listen for the SIB message, which includes a second satellite identifier;

[0315] If the second satellite identifier is included in the satellite identifier listening list information available for data transmission by the terminal, then the uplink data will be sent to the MME on the second satellite corresponding to the second satellite identifier.

[0316] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0317] The indication information is sent to the second satellite corresponding to the second satellite identifier, and the indication information is used to indicate that there is downlink data transmission after the uplink data transmission.

[0318] The arrival time of downlink data transmitted by the MME on the second satellite;

[0319] Start a second timer, wherein the time limit of the second timer is set based on the arrival time of the downlink data.

[0320] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0321] When the second timer expires, if the service link is available, listen for paging messages and prepare to receive the downlink data.

[0322] Regarding the case where the communication equipment is an MME on the second satellite:

[0323] The processor 703 described above is used to read the computer program in the memory 701 and perform the following operations:

[0324] Receive uplink data sent by the terminal and save the uplink data;

[0325] When the satellite feed link corresponding to the MME on the second satellite is available, the uplink data is sent to the ground MME.

[0326] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0327] After sending the uplink data to the ground MME, the uplink data is deleted.

[0328] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0329] The receiving terminal sends an indication message, which is used to indicate that there is a downlink data transmission after the uplink data transmission;

[0330] The arrival time of the downlink data is determined based on the location information and ephemeris information of the terminal.

[0331] The arrival time of the downlink data is sent to the terminal.

[0332] In some embodiments, the processor 703 described above is further configured to read the computer program in the memory 701 and perform the following operations:

[0333] Receive the downlink data sent by the ground MME and save the downlink data;

[0334] When the service link is available, if the terminal is within the coverage area of ​​the MME on the second satellite, a paging message is sent to the terminal to establish a connection with the terminal, and the downlink data is sent to the terminal.

[0335] In one exemplary embodiment, such as Figure 8 As shown, a structural block diagram of a ground-based MME includes:

[0336] The determination module 801 is used to determine the first satellite identifier that can be reached first from the terminal based on the satellite identifier monitoring list information that the terminal can use for data transmission.

[0337] The transmitting module 802 is used to transmit downlink data to the first on-board MME corresponding to the first satellite identifier when the satellite feed link corresponding to the first satellite identifier is available.

[0338] In some embodiments, the ground MME further includes: a receiving module 803;

[0339] The receiving module 803 is used to receive the downlink data sent by SCEF through SCS or AS;

[0340] The determining module 801 is further configured to determine the waiting time for the SCS or AS to receive an acknowledgment message for the downlink data;

[0341] The sending module 802 is also used to send the waiting time to the SCS or AS via the SCEF.

[0342] In some embodiments, the ground MME further includes a storage module 804, used to store the downlink data when the satellite feed link corresponding to the first satellite identifier is unavailable.

[0343] In some embodiments, the transmitting module 802 is further configured to send a storage instruction to the SCEF if the ground MME does not have a data storage function, or if the storage space is insufficient to store the downlink data, the storage instruction being used to instruct the storage of the downlink data.

[0344] In some embodiments, the sending module 802 is specifically used for:

[0345] When the satellite feed link corresponding to the first satellite identifier is available, sending downlink data to the first on-board MME corresponding to the first satellite identifier includes:

[0346] When the satellite feed link corresponding to the first satellite identifier is available, a downlink data transmission instruction is sent to the SCEF.

[0347] The system receives the downlink data sent by the SCEF and sends the downlink data to the MME on the first satellite.

[0348] In some embodiments, the receiving module 803 is further configured to receive a downlink data notification sent by the SGW, the downlink data notification being used to indicate that downlink data transmission is required;

[0349] The sending module 802 is also used to send a downlink data notification confirmation message to the SGW.

[0350] In some embodiments, if the ground MME does not have data storage function, or if the storage space is insufficient to store the downlink data, the downlink data notification confirmation message includes a storage indication;

[0351] The storage indication is used to indicate the storage of the downlink data.

[0352] In some embodiments, the sending module 802 is specifically used for:

[0353] When the satellite feed link corresponding to the first satellite identifier is available, sending downlink data to the first on-board MME corresponding to the first satellite identifier includes:

[0354] When the satellite feed link corresponding to the first satellite identifier is available, the downlink data is obtained from the SGW and sent to the MME on the first satellite.

[0355] In some embodiments, the receiving module 803 is further configured to receive downlink data sent by the SGW and save the downlink data before the sending module 802 sends downlink data to the MME on the first satellite corresponding to the first satellite identifier, when the satellite feed link corresponding to the first satellite identifier is unavailable.

[0356] In some embodiments, the ground MME further includes a deletion module 805, which deletes the downlink data after the sending module 802 sends downlink data to the first on-board MME corresponding to the first satellite identifier.

[0357] In some embodiments, the determining module 801 is further configured to determine, based on the first information, satellite identifier monitoring list information that the terminal can use for data transmission;

[0358] The first information includes at least one of the following:

[0359] The terminal's subscription data, satellite ephemeris information, terminal's location information, and MME default configuration information.

[0360] In one exemplary embodiment, such as Figure 9 As shown, a structural block diagram of an SCEF or SGW includes:

[0361] The receiving module 901 is used to receive a storage instruction sent by the ground MME and store downlink data, wherein the storage instruction is used to indicate the storage of the downlink data;

[0362] The transmitting module 902 is used to transmit the downlink data to the ground MME.

[0363] In some embodiments, applied to SCEF, the receiving module 901 is further configured to receive the downlink data sent by SCS or AS; the sending module 902 is further configured to send the downlink data to the ground MME; the receiving module 901 is further configured to receive the waiting time of the acknowledgment message for the downlink data sent by the ground MME; and the sending module 902 is further configured to send the waiting time to the SCS or AS.

[0364] In some embodiments, applied to the SGW, the transmitting module 902 is further configured to send a downlink data notification to the ground MME, the downlink data notification being used to indicate that downlink data transmission is required;

[0365] The receiving module 901 is specifically used to receive the downlink data notification confirmation message sent by the ground MME, wherein the downlink data notification confirmation message includes the storage indication.

[0366] In some embodiments, the SCEF or SGW further includes a deletion module 903, configured to delete the downlink data after the transmission module 902 transmits the downlink data to the ground MME.

[0367] In one exemplary embodiment, such as Figure 10 As shown, a structural block diagram of an SCS or AS includes:

[0368] The transmitting module 1001 is used to transmit downlink data to the SCEF or SGW;

[0369] The receiving module 1002 is used to receive the acknowledgment message for the downlink data sent by SCEF or SGW and wait for the specified time.

[0370] The timing module 1003 is used to start a first timer, wherein the time limit of the first timer is set based on the waiting time.

[0371] In some embodiments, the sending module 1001 is further configured to resend the downlink data to the SCEF or SGW if the acknowledgment message is not received when the first timer expires;

[0372] The timing module 1003 is further configured to cancel the first timer if the confirmation message is received within the time limit of the first timer.

[0373] In one exemplary embodiment, such as Figure 11 As shown, a structural block diagram of a terminal includes:

[0374] Receiver module 1101 is used to receive SIB messages, wherein the SIB messages include a second satellite identifier;

[0375] The sending module 1102 is used to send uplink data to the second satellite corresponding to the second satellite identifier if the satellite identifier listening list information available for data transmission by the terminal includes the second satellite identifier.

[0376] In some embodiments, the sending module 1102 is further configured to send indication information to the second satellite corresponding to the second satellite identifier, the indication information being used to indicate that there is downlink data transmission after the uplink data transmission;

[0377] The receiving module 1101 is also used to receive the arrival time of downlink data transmitted by the MME on the second satellite of the second satellite;

[0378] The terminal further includes a timing module 1103, used to start a second timer, wherein the time limit of the second timer is set based on the arrival time of the downlink data.

[0379] In some embodiments, the terminal further includes a listening module 1104, configured to listen for paging messages and prepare to receive the downlink data if the service link is available when the second timer expires.

[0380] In one exemplary embodiment, such as Figure 12 As shown, a structural block diagram of an onboard MME for a second satellite includes:

[0381] The receiving module 1201 is used to receive uplink data sent by the terminal and save the uplink data;

[0382] The transmitting module 1202 is used to transmit the uplink data to the ground MME when the satellite feed link corresponding to the MME on the second satellite is available.

[0383] In some embodiments, the second satellite MME further includes a deletion module 1203, which deletes the uplink data after the transmission module 1202 transmits the uplink data to the ground MME.

[0384] In some embodiments, the receiving module 1201 is further configured to receive indication information sent by the terminal, the indication information being used to indicate that there is downlink data transmission after the uplink data transmission;

[0385] The second satellite's onboard MME also includes: a determination module, used to determine the arrival time of the downlink data based on the terminal's location information and ephemeris information;

[0386] The sending module 1202 is also used to send the arrival time of the downlink data to the terminal.

[0387] In some embodiments, the second satellite MME further includes: a receiving module 1201, which is also used to receive the downlink data transmitted by the ground MME and save the downlink data;

[0388] The sending module 1202 is also configured to, when the service link is available, if the terminal is within the coverage area of ​​the MME on the second satellite, send a paging message to the terminal, establish a connection with the terminal, and send the downlink data to the terminal.

[0389] It should be noted that the module division in the embodiments of this application is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0390] If the integrated modules described above are implemented as software functional modules and sold or used as independent products, they can be stored in a processor-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application.

[0391] It should be noted that the apparatus provided in this embodiment of the invention can implement all the method steps implemented in the above method embodiment and can achieve the same technical effect. Therefore, the parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0392] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements all the method steps implemented in the above method embodiments.

[0393] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements all the method steps implemented in the above method embodiments.

[0394] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0395] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0396] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A data transmission method, characterized in that, Applied to ground-based MMEs, the method includes: Based on the satellite identifier monitoring list information that the terminal can use for data transmission, determine the first satellite identifier that is most accessible to the terminal next; When the satellite feed link corresponding to the first satellite identifier is available, downlink data is sent to the first onboard MME corresponding to the first satellite identifier.

2. The method according to claim 1, characterized in that, The method further includes: Receive the downlink data sent by SCEF via SCS or AS; Determine the waiting time for the SCS or AS to receive an acknowledgment message for the downlink data; The waiting time is sent to the SCS or AS via the SCEF.

3. The method according to claim 2, characterized in that, Before sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, the method further includes: When the satellite feed link corresponding to the first satellite identifier is unavailable, the downlink data is saved.

4. The method according to claim 2, characterized in that, The method further includes: If the ground MME does not have data storage function, or if the storage space is insufficient to store the downlink data, a storage instruction is sent to the SCEF, the storage instruction being used to instruct the storage of the downlink data.

5. The method according to claim 4, characterized in that, When the satellite feed link corresponding to the first satellite identifier is available, sending downlink data to the first on-board MME corresponding to the first satellite identifier includes: When the satellite feed link corresponding to the first satellite identifier is available, a downlink data transmission instruction is sent to the SCEF. The system receives the downlink data sent by the SCEF and sends the downlink data to the MME on the first satellite.

6. The method according to claim 1, characterized in that, The method further includes: Receive downlink data notification sent by SGW, the downlink data notification being used to indicate that downlink data transmission is required; Send a downlink data notification confirmation message to the SGW.

7. The method according to claim 1, characterized in that, If the ground MME does not have data storage function, or if the storage space is insufficient to store the downlink data, the downlink data notification confirmation message includes a storage instruction; The storage indication is used to indicate the storage of the downlink data.

8. The method according to claim 7, characterized in that, When the satellite feed link corresponding to the first satellite identifier is available, sending downlink data to the first on-board MME corresponding to the first satellite identifier includes: When the satellite feed link corresponding to the first satellite identifier is available, the downlink data is obtained from the SGW and sent to the MME on the first satellite.

9. The method according to claim 6, characterized in that, Before sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, the method further includes: When the satellite feed link corresponding to the first satellite identifier is unavailable, the downlink data sent by the SGW is received and the downlink data is saved.

10. The method according to claim 3 or 9, characterized in that, After sending downlink data to the MME on the first satellite corresponding to the first satellite identifier, the method further includes: Delete the downlink data.

11. The method according to claim 1, characterized in that, The method further includes: Based on the first information, determine the satellite identifier monitoring list information that the terminal can use for data transmission; The first information includes at least one of the following: The terminal's subscription data, satellite ephemeris information, terminal's location information, and MME default configuration information.

12. The method according to claim 11, characterized in that, The method further includes: Send the satellite identifier monitoring list information that the terminal can use for data transmission to the terminal; And / or, The terminal's context information is sent to the onboard MME corresponding to the range indicated by the satellite identifier listening list information.

13. The method according to claim 1, characterized in that, The step of determining the first satellite identifier that can reach the terminal first, based on the satellite identifier monitoring list information available for data transmission from the terminal, includes: Based on the terminal's location information and the satellite identifier monitoring list information that the terminal can use for data transmission, the first satellite identifier that can reach the terminal first is determined.

14. A data transmission method, characterized in that, Applied to SCEF or SGW, the method includes: Receive a storage instruction sent by the ground MME and store downlink data, wherein the storage instruction is used to indicate the storage of the downlink data; The downlink data is sent to the ground MME.

15. The method according to claim 14, characterized in that, Applied to SCEF, the method further includes: Receive the downlink data sent by SCS or AS; The downlink data is sent to the ground MME; The system receives the confirmation message for the downlink data sent by the ground MME and sends the waiting time to the SCS or the AS.

16. The method according to claim 14, characterized in that, When applied to SGW, the method further includes: Send a downlink data notification to the ground MME, the downlink data notification indicating that downlink data transmission is required; Receive storage instructions transmitted by the ground MME, including: Receive a downlink data notification confirmation message sent by the ground MME, the downlink data notification confirmation message including the storage indication.

17. The method according to claim 14, characterized in that, After sending the downlink data to the ground MME, the method further includes: Delete the downlink data.

18. A data transmission method, characterized in that, Applied to SCS or AS, the method includes: Send downlink data to SCEF or SGW; Waiting time for receiving confirmation messages for the downlink data sent by SCEF or SGW; Start a first timer, wherein the time limit of the first timer is set based on the waiting time.

19. The method according to claim 18, characterized in that, The method further includes: If the acknowledgment message is not received when the first timer expires, the downlink data is retransmitted to SCEF or SGW; If the confirmation message is received within the time limit of the first timer, the first timer is cancelled.

20. A data transmission method, characterized in that, Applied to a terminal, the method includes: When it is determined that there is uplink data to be transmitted, listen for the SIB message, which includes a second satellite identifier; If the second satellite identifier is included in the satellite identifier listening list information available for data transmission by the terminal, then the uplink data will be sent to the MME on the second satellite corresponding to the second satellite identifier.

21. The method according to claim 20, characterized in that, The method further includes: The indication information is sent to the second satellite corresponding to the second satellite identifier, and the indication information is used to indicate that there is downlink data transmission after the uplink data transmission. The arrival time of downlink data transmitted by the MME on the second satellite; Start a second timer, wherein the time limit of the second timer is set based on the arrival time of the downlink data.

22. The method according to claim 21, characterized in that, The method further includes: When the second timer expires, if the service link is available, listen for paging messages and prepare to receive the downlink data.

23. A data transmission method, characterized in that, Applied to MME on a second satellite, the method includes: Receive uplink data sent by the terminal and save the uplink data; When the satellite feed link corresponding to the MME on the second satellite is available, the uplink data is sent to the ground MME.

24. The method according to claim 23, characterized in that, After sending the uplink data to the ground MME, the method further includes: Delete the aforementioned upstream data.

25. The method according to claim 23, characterized in that, The method further includes: The receiving terminal sends an indication message, which is used to indicate that there is a downlink data transmission after the uplink data transmission; The arrival time of the downlink data is determined based on the location information and ephemeris information of the terminal. The arrival time of the downlink data is sent to the terminal.

26. The method according to claim 25, characterized in that, The method further includes: Receive the downlink data sent by the ground MME and save the downlink data; When the service link is available, if the terminal is within the coverage area of ​​the MME on the second satellite, a paging message is sent to the terminal to establish a connection with the terminal, and the downlink data is sent to the terminal.

27. A ground-based MME, characterized in that, include: Memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor. The processor is configured to read a computer program from the memory and execute the method as described in any one of claims 1 to 13.

28. An SCEF or SGW, characterized in that, include: Memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor. The processor is configured to read a computer program from the memory and execute the method as described in any one of claims 14 to 17.

29. An SCS or AS, characterized in that, include: Memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor. The processor is configured to read the computer program in the memory and execute the method as described in claim 18 or 19.

30. A terminal, characterized in that, include: Memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor. The processor is configured to read a computer program from the memory and execute the method as described in any one of claims 20 to 22.

31. A second-satellite on-board MME, characterized in that, include: Memory, transceiver, processor: The memory is used to store computer programs; the transceiver is used to send and receive data under the control of the processor. The processor is configured to read a computer program from the memory and execute the method as described in any one of claims 23 to 26.

32. A ground-based MME, characterized in that, include: The determination module is used to determine the first satellite identifier that can be reached first from the terminal based on the satellite identifier monitoring list information that the terminal can use for data transmission. The transmitting module is used to transmit downlink data to the first on-board MME corresponding to the first satellite identifier when the satellite feed link corresponding to the first satellite identifier is available.

33. An SCEF or SGW, characterized in that, include: A receiving module is configured to receive a storage instruction transmitted by a ground MME and store downlink data, wherein the storage instruction is used to indicate the storage of the downlink data; The transmitting module is used to transmit the downlink data to the ground MME.

34. An SCS or AS, characterized in that, include: The transmitting module is used to send downlink data to SCEF or SGW; The receiving module is configured to wait for receiving confirmation messages for the downlink data sent by SCEF or SGW. A timing module is used to start a first timer, wherein the time limit of the first timer is set based on the waiting time.

35. A terminal, characterized in that, include: A receiving module is configured to receive SIB messages, wherein the SIB messages include a second satellite identifier; The sending module is configured to send uplink data to the second satellite corresponding to the second satellite identifier if the satellite identifier listening list information available for data transmission by the terminal includes the second satellite identifier.

36. A second-satellite on-board MME, characterized in that, include: The receiving module is used to receive uplink data sent by the terminal through the base station on the second satellite and to save the uplink data; The transmitting module is used to transmit the uplink data to the ground MME when the satellite feed link corresponding to the MME on the second satellite is available.

37. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method according to any one of claims 1 to 26.

38. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method according to any one of claims 1 to 26.

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