Mobility management method and apparatus

Abstract

The present specification relates to the technical field of communication, and particularly relates to a mobility management method and device. The mobility management method comprises: determining a TNL link of the NTN network device; and sending indication information to a core network device, wherein the indication information is used for indicating a switching configuration of the TNL link. The embodiment of the present specification can reduce the number of signaling interactions of the NG interface.

Description

Technical Field

[0001] This specification relates to the field of communication technology, and in particular to a mobility management method and device. Background Technology

[0002] Non-terrestrial networks (NTNs) are characterized by their large coverage area and flexible networking capabilities, providing ubiquitous coverage regardless of terrain. However, as NTN equipment moves, its connection to terrestrial gateways constantly changes, leading to frequent and numerous signaling interactions at the NG interface between the core and access networks. This can easily cause signaling storms and hinder mobility management of the NG interface. Furthermore, communication between NTN equipment and core network equipment is wireless, resulting in significant transmission latency over long distances. This further increases the likelihood of signaling storms. Summary of the Invention

[0003] This specification provides a mobility management method and device to reduce the number of signaling interactions on the NG interface.

[0004] According to a first aspect of the embodiments of this specification, a mobility management method is provided, applied to an NTN network device, comprising:

[0005] Determine the Transport Network Layer (TNL) link of the NTN network device;

[0006] Send indication information to the core network equipment, the indication information being used to indicate the handover configuration of the TNL link.

[0007] According to a second aspect of the embodiments of this specification, a mobility management method is provided, applied to a core network device, comprising:

[0008] Receive indication information from NTN network devices, the indication information being used to indicate the handover configuration of TNL links;

[0009] Update the availability status of the TNL link according to the indicated information.

[0010] According to a third aspect of the embodiments of this specification, a mobility management method is provided, applied to a first NTN network device, comprising:

[0011] Determine the TNL link of the first NTN network device;

[0012] Send indication information to the second NTN network device, the indication information being used to indicate the handover configuration of the TNL link.

[0013] According to a fourth aspect of the embodiments of this specification, a mobility management method is provided, applied to a second NTN network device, comprising:

[0014] Receive indication information from the first NTN network device, the indication information being used to indicate the handover configuration of the TNL link;

[0015] The availability status of the TNL link is determined based on the indicated information.

[0016] According to a fifth aspect of the embodiments of this specification, an NTN network device is provided, the NTN network device including a processor and a memory, the memory being used to store a computer program executable on the processor, the processor executing the computer program to implement instructions of the methods described in the first, third, or fourth aspects.

[0017] According to a sixth aspect of the embodiments of this specification, a core network device is provided, the core network device including a processor and a memory, the memory being used to store a computer program executable on the processor, the processor executing the computer program to implement instructions for the method of the second aspect.

[0018] In the technical solutions of the embodiments of this specification, the NTN network device can send indication information to the core network device. The indication information is used to indicate the handover configuration of the TNL link. By indicating the handover configuration of the TNL link, the availability status of the TNL link can be indicated, enabling the core network device to automatically update the TNL link on the NG interface, ensuring the connection of the NG interface during mobility management. This reduces the number of signaling interactions on the NG interface and also lowers service transmission latency.

[0019] In the technical solution of this specification's embodiments, the first NTN network device can send indication information to the second NTN network device. The indication information is used to indicate the handover configuration of the TNL link. By indicating the handover configuration of the TNL link, the availability status of the TNL link can be indicated, allowing the second NTN network device to select a data transmission path with the core network device based on the availability status of the TNL link, thus ensuring the connection of the second NTN network device's NG interface during mobility management. This reduces the number of signaling interactions on the NG interface corresponding to the second NTN network device and also reduces service transmission latency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of power supply link switching in the embodiments of this specification;

[0022] Figure 2 This is a schematic diagram of the soft handover process in related technologies;

[0023] Figure 3 This is a schematic diagram of the hard handover process in related technologies;

[0024] Figure 4 This is a flowchart illustrating the mobility management method in the embodiments of this specification;

[0025] Figure 5 This is a flowchart illustrating the mobility management method in the embodiments of this specification;

[0026] Figure 6 This is a schematic diagram of the soft handover process in the embodiments of this specification;

[0027] Figure 7 This is a schematic diagram of the hard handover process in the embodiments of this specification;

[0028] Figure 8 This is a schematic diagram illustrating the connection establishment process between NTN network devices and core network devices in the embodiments of this specification;

[0029] Figure 9 This is a flowchart illustrating the mobility management method in the embodiments of this specification;

[0030] Figure 10 This is a flowchart illustrating the mobility management method in the embodiments of this specification;

[0031] Figure 11 This is a flowchart illustrating the mobility management method in the embodiments of this specification;

[0032] Figure 12a This is a schematic diagram illustrating the interaction process between the first NTN network device, the second NTN network device, and the core network device in the embodiments of this specification;

[0033] Figure 12b This is a schematic diagram illustrating the interaction process between the first NTN network device, the second NTN network device, and the core network device in the embodiments of this specification;

[0034] Figure 13 This is a schematic diagram illustrating the interaction process between the first NTN network device, the second NTN network device, and the core network device in the embodiments of this specification;

[0035] Figure 14 This is a flowchart illustrating the mobility management method in the embodiments of this specification;

[0036] Figure 15 This is a schematic diagram of the mobility management device in the embodiments of this specification;

[0037] Figure 16 This is a schematic diagram of the mobility management device in the embodiments of this specification;

[0038] Figure 17 This is a schematic diagram of the mobility management device in the embodiments of this specification;

[0039] Figure 18 This is a schematic diagram of the mobility management device in the embodiments of this specification. Detailed Implementation

[0040] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. The specific embodiments described herein are only used to explain this disclosure, and not to limit this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure are within the scope of protection of this disclosure. In addition, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0041] The NG interface serves as the interface between network devices and core network devices. NG interfaces can include NG-C and NG-U interfaces. The NG-C interface connects the network device to the AMF (Access and Mobility Management Function) entity within the core network device. The NG-U interface connects the network device to the UPF (User Plane Function) entity within the core network device. In terrestrial networks (TN), TN network devices are located in fixed positions. Signaling on the NG interface is transmitted via wired connections, ensuring both latency and reliability. Frequent signaling interactions, whether for creating or deleting NG interfaces or updating RAN configurations, typically do not cause latency or reliability issues. However, in non-terrestrial networks, NTN network devices and core network devices are connected wirelessly instead of wired connections, leading to greater transmission latency due to longer distances. The movement of NTN network devices results in numerous and frequent signaling interactions on the NG interface, potentially causing signaling storms and hindering mobility management on the NG interface.

[0042] Taking NTN network equipment as an example, a satellite-based base station is a base station deployed on satellite equipment. The satellite-based base station can communicate with the core network equipment through a gateway station. During the movement of the satellite-based base station, the connection between the satellite-based base station and the gateway station changes, resulting in a feeder link switchover. The feeder link is the physical link between the satellite-based base station and the gateway station. Feeder link switching can be either soft or hard. For soft switching, the connection between the new and old feeder links can be maintained simultaneously during the switching process, and then the old feeder link can be disconnected at an appropriate time. For hard switching, the old feeder link can be disconnected and the new feeder link can be connected during the switching process. Disconnecting the old feeder link and connecting the new feeder link can be done simultaneously or at short intervals. For example, the old feeder link can be disconnected first, and then the new feeder link can be connected within a set time. Alternatively, the new feeder link can be connected first, and then the old feeder link can be disconnected within a set time. Furthermore, the connection of the new feeder link and the disconnection of the old feeder link can occur simultaneously. The new feeder link is a newly added feeder link between the satellite-based base station and the gateway station. The old feeder link is the existing feeder link between the satellite-based base station and the gateway station. Please refer to [link / reference]. Figure 1The satellite-borne base station can connect to gateway station 1, thereby connecting to core network equipment via feeder link 1. Feeder link 1 is the physical link between the satellite-borne base station and gateway station 1. Feeder link 1 can be understood as the old feeder link. Due to the movement of the satellite-borne base station, it can connect to gateway station 2, thereby connecting to core network equipment via feeder link 2. Feeder link 2 is the physical link between the satellite-borne base station and gateway station 2. Feeder link 2 can be understood as the new feeder link.

[0043] A single power supply link can support one or more TNL (Transport Network Layer) links. A TNL link is a logical or physical link between the onboard base station and the core network equipment, used for data transmission between them. Please continue reading. Figure 1 Feeder link 1 supports TNL link 1. Feeder link 2 supports TNL link 2. Due to the movement of the onboard base station, a switch occurs from feeder link 1 to feeder link 2, which in turn causes a switch from TNL link 1 to TNL link 2. Through the TNL link switch, the onboard base station and core network equipment can maintain NGAP connectivity at the Radio Network Layer (RNL), but the path at the Transport Network Layer (TNL) changes.

[0044] Corresponding to the switching type of the power supply link, the switching type of the TNL link can include soft switching and hard switching.

[0045] In related technologies, the soft handover process is as follows: Figure 2 As shown. The satellite-based base station is connected to gateway station 1. The physical link between the satellite-based base station and gateway station 1 is feeder link 1. Feeder link 1 supports TNL link 1. Gateway station 1 is pre-configured with the address of TNL link 1. The satellite-based base station can obtain the address of TNL link 1 through gateway station 1; it can establish an SCTP (Stream Control Transmission Protocol) connection through the address of TNL link 1. Core network equipment can use TNL link 1 to send downlink data to the satellite-based base station. For example, core network equipment can send downlink data to gateway station 1, and gateway station 1 receives and sends downlink data to the satellite-based base station. The satellite-based base station can use TNL link 1 to send uplink data to core network equipment. For example, satellite-based base station can send uplink data to gateway station 1, and gateway station 1 receives and sends uplink data to core network equipment.

[0046] Due to the movement of the satellite-based base station, it connects to gateway station 2. The physical link between the satellite-based base station and gateway station 2 is feeder link 2. Feeder link 2 supports TNL link 2. Gateway station 2 is pre-configured with the address of TNL link 2. The satellite-based base station obtains the address of TNL link 2 through gateway station 2; it can establish an SCTP connection using the address of TNL link 2. The handover type of TNL link 2 is soft handover. At this time, the satellite-based base station simultaneously maintains the SCTP connection corresponding to TNL link 1 and the SCTP connection corresponding to TNL link 2. Based on TNL link 1 and TNL link 2, the satellite-based base station can use multiple different paths to send uplink data.

[0047] The satellite-based base station can send a first RAN (Radio Access Network) configuration update message to the core network equipment. This message indicates that the core network equipment can connect to the satellite-based base station via TNL link 2. The core network equipment can add TNL link 2 to the NG interface based on this message, thereby updating the NG interface's configuration. This NG interface serves as the interface between the satellite-based base station and the core network equipment. The core network equipment can then send a first RAN configuration update acknowledgment message to the satellite-based base station. At this time, the core network equipment simultaneously maintains the SCTP connection corresponding to both TNL link 1 and TNL link 2. Based on TNL link 1 and TNL link 2, the core network equipment can utilize multiple different paths to transmit downlink data.

[0048] The satellite-borne base station and core network equipment can perform PDU (Protocol Data Unit) session modification for the UE (User Equipment) of the current serving cell in preparation for user plane data transmission.

[0049] When the movement of the satellite-based base station causes the connection with gateway station 1 to be lost, TNL link 1 becomes unavailable. The satellite-based base station can send a second RAN configuration update message to the core network equipment. The second RAN configuration update message indicates that the core network equipment cannot connect to the satellite-based base station via TNL link 1. The core network equipment can remove TNL link 1 on the NG interface and stop sending data to gateway station 1 based on the second RAN configuration update message. The core network equipment can send a second RAN configuration update confirmation message to the satellite-based base station. The information elements (IEs) in the second RAN configuration update message are shown in Table 1 below.

[0050] Table 1

[0051]

[0052]

[0053] At this point, the core network equipment maintains the SCTP connection corresponding to TNL link 2, but no longer maintains the SCTP connection corresponding to TNL link 1. The core network equipment can send downlink data to gateway station 2, and gateway station 2 can receive and send downlink data to the satellite-based base station.

[0054] In the aforementioned soft handover process, the first RAN configuration update message instructs the core network equipment to add TNL link 2 on the NG interface, and the second RAN configuration update message instructs the core network equipment to remove TNL link 1 on the NG interface. After receiving the first RAN configuration update message, the core network equipment can send downlink data to gateway station 1 and / or gateway station 2 until it receives the second RAN configuration update message, at which point it stops sending data to gateway station 2. Therefore, the signaling interaction between the satellite base station and the core network equipment includes not only the first RAN configuration update message and the first RAN configuration update confirmation message, but also the second RAN configuration update message and the second RAN configuration update confirmation message. The frequent and numerous signaling interactions on the NG interface can easily cause signaling storms, which are detrimental to the mobility management of the satellite base station and may also cause service transmission delays.

[0055] In related technologies, the hard handover process is as follows: Figure 3 As shown. The satellite-based base station is connected to gateway station 1. The physical link between the satellite-based base station and gateway station 1 is feeder link 1. Feeder link 1 supports TNL link 1. Gateway station 1 is pre-configured with the address of TNL link 1. The satellite-based base station can obtain the address of TNL link 1 through gateway station 1; it can establish an SCTP (Stream Control Transmission Protocol) connection through the address of TNL link 1. Core network equipment can use TNL link 1 to send downlink data to the satellite-based base station. For example, core network equipment can send downlink data to gateway station 1, and gateway station 1 can receive and send downlink data to the satellite-based base station. The satellite-based base station can use TNL link 1 to send uplink data to core network equipment. For example, satellite-based base station can send uplink data to gateway station 1, and gateway station 1 can receive and send uplink data to core network equipment.

[0056] Due to the movement of the satellite-based base station, it connects to gateway station 2. The physical link between the satellite-based base station and gateway station 2 is feeder link 2. Feeder link 2 supports TNL link 2. Gateway station 2 is pre-configured with the address of TNL link 2. The satellite-based base station can obtain the address of TNL link 2 through gateway station 2. The satellite-based base station can establish an SCTP connection through the address of TNL link 2. The handover type of TNL link 2 is hard handover. At this time, the satellite-based base station can disconnect from gateway station 1. The satellite-based base station maintains the SCTP connection corresponding to TNL link 2 and no longer maintains the SCTP connection corresponding to TNL link 1.

[0057] The satellite-based base station can send a first RAN configuration update message to the core network equipment. This message indicates that the core network equipment can connect to the satellite-based base station via TNL link 2. The core network equipment can add TNL link 2 to the NG interface based on the first RAN configuration update message, thereby updating the NG interface configuration. The core network equipment can also send a first RAN configuration update confirmation message to the satellite-based base station. At this time, the core network equipment simultaneously maintains the SCTP connection corresponding to TNL link 1 and the SCTP connection corresponding to TNL link 2. The core network equipment can then send downlink data to gateway station 1 or gateway station 2.

[0058] The satellite-borne base station and core network equipment can perform PDU (Protocol Data Unit) session modification for the UE (User Equipment) of the current serving cell in preparation for user plane data transmission.

[0059] The connection between the satellite base station and gateway station 1 is lost, and TNL link 1 becomes unavailable. Therefore, the satellite base station needs to send a second RAN configuration update message to the core network equipment. The second RAN configuration update message indicates that the core network equipment cannot connect to the satellite base station via TNL link 1. The core network equipment can remove TNL link 1 on the NG interface and stop sending data to gateway station 1 based on the second RAN configuration update message. The core network equipment can send a second RAN configuration update confirmation message to the satellite base station. The information elements (IEs) in the second RAN configuration update message are shown in Table 1.

[0060] At this point, the core network equipment maintains the SCTP connection corresponding to TNL link 2, but no longer maintains the SCTP connection corresponding to TNL link 1. The core network equipment can send downlink data to gateway station 2, and gateway station 2 can receive and send downlink data to the satellite-based base station.

[0061] In the aforementioned hard handover process, the first RAN configuration update message instructs the core network equipment to add TNL link 2 on the NG interface, and the second RAN configuration update message instructs the core network equipment to remove TNL link 1 on the NG interface. After receiving the first RAN configuration update message, the core network equipment can send downlink data to gateway station 1 and / or gateway station 2 until it receives the second RAN configuration update message, at which point it stops sending data to gateway station 2. Therefore, the signaling interaction between the satellite base station and the core network equipment includes not only the first RAN configuration update message and the first RAN configuration update confirmation message, but also the second RAN configuration update message and the second RAN configuration update confirmation message. The frequent and numerous signaling interactions on the NG interface can easily cause signaling storms, which is detrimental to the mobility management of the satellite base station and may also cause service transmission delays.

[0062] Furthermore, during the period between receiving the first RAN configuration update message and receiving the second RAN configuration update message, the satellite base station has disconnected from gateway station 1. However, the core network equipment is unaware that the satellite base station has disconnected from gateway station 1, and TNL link 1 on the NG interface has not been removed. Therefore, the core network equipment may send downlink data to gateway station 1. If the core network equipment sends downlink data to gateway station 1, gateway station 1, upon receiving the downlink data, will be unable to forward it to the satellite base station, resulting in downlink data transmission failure and impacting service continuity.

[0063] This specification provides a mobility management method through its embodiments. This mobility management method can be applied to non-terrestrial network (NTN) devices. Please refer to... Figure 4 and Figure 5 The mobility management method may include the following steps.

[0064] Step 41: Determine the TNL link of the NTN network device.

[0065] Step 42: Send instruction information to the core network equipment.

[0066] Network equipment refers to equipment that connects terminal devices to a communication network and provides services to those terminal devices. Network equipment includes, but is not limited to, the following: base stations (BS), access points (AP), transmission reception points (TRP), broadcast transmitters, mobile management entities (MME), gateways, servers, radio network controllers (RNC), and base station controllers (BSC). Base stations include, but are not limited to, NodeBs (or NBs), evolved NodeBs (or eNodeBs or eNBs), 5G base stations (gNBs), 6G base stations, and future base stations. It may also include remote radio heads (RRHs), remote radio units (RRUs), relays, or low-power nodes (e.g., femto, pico). NTN network equipment may include network equipment deployed on satellite equipment (e.g., satellite-borne base stations), network equipment deployed on high-altitude platforms, drone network equipment, aircraft network equipment, and communication balloon network equipment. Satellite equipment includes highly elliptical orbit (HEO) satellites, GEO satellites, medium Earth orbit (MEO) satellites, and low Earth orbit (LEO) satellites.

[0067] Core network equipment enables functions such as user access control, mobility management, session management, user security authentication, and billing. Core network equipment includes entities such as AMF (access and mobility management function), SMF (session management function), UPF (user plane function), UDM (unified data management), and PCC (policy and charging control). All entities within the core network equipment can be deployed on the ground. Alternatively, one or more entities within the core network equipment (such as the AMF) can be deployed on non-terrestrial surfaces (such as satellite equipment).

[0068] A feeder link is the physical link between NTN network devices and a gateway station. A gateway station, also known as a gate station, ground station, or earth station, connects NTN network devices and core network devices. When NTN network devices are moved, the connection between the NTN network devices and the gateway station changes, causing the feeder link to switch. A feeder link can support one or more TNL (Transport Network Layer) links. A TNL link is a logical or physical link between network devices and core network devices, used for data transmission between them. Switching of a feeder link causes a corresponding switch in the TNL links it supports.

[0069] NTN network devices can determine their own TNL links and send indication information to core network devices. This indication information is used to indicate the handover configuration of the TNL links. By indicating the handover configuration of the TNL links on the NTN network device side, the availability status of the TNL links can be indicated, enabling the core network device to update the TNL links on the NG interface itself, ensuring the connection of the NG interface during mobility management. This reduces the number of signaling interactions on the NG interface (e.g., the NG-C interface) and also reduces service transmission latency. For example, NTN network devices do not need to send separate RAN configuration update messages to the core network device for adding new TNL links (e.g., the first TNL link) and for removing old TNL links (e.g., the second TNL link), thereby reducing the number of signaling interactions between the NTN network device and the core network device.

[0070] In some embodiments, the type of power supply link handover includes soft handover and hard handover. For soft handover, during the handover process, the connection between the new and old power supply links can be maintained simultaneously, and then the old power supply link can be disconnected at an appropriate time. For hard handover, during the handover process, the old power supply link can be disconnected and the new power supply link can be connected. Disconnecting the old power supply link and connecting the new power supply link can be performed simultaneously or at short intervals. For example, the old power supply link can be disconnected first and then the new power supply link can be connected within a set time. Alternatively, the new power supply link can be connected first and then the old power supply link can be disconnected within a set time. Or, the connection of the new power supply link and the disconnection of the old power supply link can be performed simultaneously.

[0071] Corresponding to the handover types of feeder links, TNL link handover types can include soft handover and hard handover. For soft handover, during the handover process, the connection between the new TNL link and the old TNL link can be maintained simultaneously. The NTN network device and the core network device can maintain the logical connection of the NG interface through one or more TNL links. For hard handover, during the handover process, the old TNL link can be disconnected and the new TNL link can be connected. Disconnecting the old TNL link and connecting the new TNL link can be performed simultaneously or at short intervals. For example, the old TNL link can be disconnected first and then the new TNL link can be connected within a set time. Alternatively, the new TNL link can be connected first and then the old TNL link can be disconnected within a set time. Or, the connection of the new TNL link and the disconnection of the old TNL link can be performed simultaneously. For hard handover, during the handover process, the NTN network device and the core network device can maintain the logical connection of the NG interface through a single TNL link.

[0072] A new feeder link is a newly added feeder link between the satellite-based base station and the gateway station. A new TNL link is a newly added TNL link, such as a TNL link supported by the new feeder link. An old feeder link is an existing feeder link between the satellite-based base station and the gateway station. An old TNL link is an existing TNL link, such as a TNL link supported by the old feeder link.

[0073] In some embodiments of step 41, the connection between the NTN network device and the gateway station may change due to the movement of the NTN network device, resulting in a power supply link switchover. The NTN network device can determine the TNL link when a power supply link switchover occurs. For example, the NTN network device can determine the TNL link when connecting to a new gateway station.

[0074] When a power supply link switchover occurs, the NTN network device needs to send a RAN Configuration Update message to the core network device to update the core network device's configuration. This RAN Configuration Update message can carry the indication information. In this way, the NTN network device can indicate the switchover configuration of the TNL link by updating its configuration.

[0075] Alternatively, the NTN network device can determine the TNL link when it needs to establish a connection with the core network device. For example, the NTN network device can determine the TNL link when it first needs to establish a connection with the core network device. Alternatively, the NTN network device can also predetermine the TNL link before establishing a connection with the core network device. When the NTN network device needs to establish a connection with the core network device, it can send an NG Setup Request message to the core network device. The indication information can then be carried by the NG Setup Request message. In this way, the NTN network device can indicate the switching configuration of the TNL link through connection establishment.

[0076] In some embodiments of step 41, the NTN network device may identify one or more first TNL links. A first TNL link is a newly added TNL link between the core network device and the NTN network device. For example, a first TNL link may be a TNL link for which a communication connection has not yet been established, or it may be a TNL link for which a communication connection has been established but has not yet been used for data transmission.

[0077] As an example, an NTN network device can identify one or more first TNL links when a feeder link switch occurs. For instance, an NTN network device can select a TNL link supported by the new feeder link as the first TNL link.

[0078] As another example, an NTN network device can identify one or more first TNL links when it needs to establish a connection with a core network device. Alternatively, an NTN network device can also pre-identify one or more first TNL links before establishing a connection with a core network device. These first TNL links are TNL links that the NTN network device may establish in the future during its movement. The NTN network device can obtain potentially established TNL links as first TNL links based on its own movement trajectory.

[0079] In non-terrestrial networks, NTN network devices exhibit high dynamism. The movement characteristics of NTN network devices are predictable. The connections between NTN network devices and gateway stations are predetermined. NTN network devices know which one or more gateway stations they are connected to. Furthermore, gateway stations are connected to core network equipment. Core network equipment is aware of the gateway stations it connects to. The IP address and location information of the gateway stations do not change. Gateway station information and core network equipment information can be pre-sent to the NTN network devices. For example, this can be done through OAM (Operation Administration and Maintenance) configuration or pre-configuration. Based on one or more of its own movement trajectory, gateway station information, and core network equipment information, the NTN network device can determine a potentially future TNL link as its first TNL link. Potentially future TNL links may include TNL links supported by gateway stations that the NTN network device may connect to in the future. For example, the NTN network device may include a satellite-based base station. The satellite-borne base station determines the TNL link that may be established in the future as the first TNL link based on one or more of its own motion trajectory, ephemeris information, gateway station information, core network equipment information, etc.

[0080] In some embodiments of step 41, the NTN network device may identify one or more second TNL links. The second TNL link is an existing TNL link between the core network device and the NTN network device. The second TNL link has been used for data transmission between the NTN network device and the core network device. Using the second TNL link, the core network device can send downlink data to the NTN network device, and the NTN network device can send uplink data to the core network device.

[0081] As an example, NTN network devices can identify one or more second TNL links when a feeder link switch occurs. The NTN network device can acquire a TNL link supported by the old feeder link as the second TNL link.

[0082] In some embodiments of step 42, the NTN network device can obtain the switching configuration of the TNL link.

[0083] The handover configuration of a TNL link can be pre-configured, or it can be calculated based on a pre-configured configuration. The handover configuration of a TNL link can include at least one of the following: the handover type of the first TNL link, the validity period of the first TNL link (hereinafter referred to as the first validity period), the address of the first TNL link, the validity period of the second TNL link (hereinafter referred to as the second validity period), and the address of the second TNL link.

[0084] The handover type for the first TNL link can be selected from hard handover and soft handover. The handover type for the first TNL link can be pre-configured. For example, the handover type for the first TNL link can be configured based on the capabilities of the NTN network device and / or service requirements. The NTN network device can obtain the pre-configured handover type for the first TNL link.

[0085] The first valid time is used to represent the available time of the first TNL link. The first valid time may include one or more of the start time, disconnection time, and connection period of the first TNL link. Within the first valid time (e.g., between the start time and the disconnection time; or, for example, within the connection period), data transmission can be performed using the first TNL link. Outside the first valid time (e.g., before the start time; or, for example, after the disconnection time; or, for example, outside the connection period), the first TNL link is disconnected, and therefore data transmission cannot be performed using the first TNL link. The first valid time can be determined based on the motion characteristics of the NTN network device. For example, the NTN network device is a satellite-based base station. The NTN network device can calculate the first valid time of the first TNL link based on ephemeris information or satellite service time.

[0086] The second valid time is used to indicate the available time of the second TNL link. The second valid time may include one or more of the start time, disconnection time, and connection period of the second TNL link. Within the second valid time (e.g., between the start time and the disconnection time; or, for example, within the connection period), data transmission can be performed using the second TNL link. Outside the second valid time (e.g., before the start time; or, for example, after the disconnection time; or, for example, outside the connection period), the second TNL link is disconnected, and therefore data transmission cannot be performed using the second TNL link. The second valid time can be determined based on the motion characteristics of the NTN network device. For example, the NTN network device is a satellite-based base station. The NTN network device can calculate the second valid time of the second TNL link based on ephemeris information or satellite service time.

[0087] The address of the first TNL link is used to add and / or remove the first TNL link on the NG interface. Adding and / or removing the address of the first TNL link on the NG interface enables the addition and / or removal of the first TNL link. The address of the first TNL link can include at least one of the following: a TNL transport layer address, a TNL transport layer AMF address, or a TNL transport layer gateway address. The address of the first TNL link can be pre-configured or pre-obtained. For example, the address of the first TNL link can be pre-sent to the NTN network device through OAM configuration or pre-configuration.

[0088] The address of the second TNL link is used to add and / or remove the second TNL link on the NG interface. Adding and / or removing the address of the second TNL link on the NG interface enables the addition and / or removal of the second TNL link. The address of the second TNL link can include at least one of the following: a TNL transport layer address, a TNL transport layer AMF address, or a TNL transport layer gateway address. The address of the second TNL link can be pre-configured or pre-obtained. For example, the address of the second TNL link can be pre-sent to the NTN network device through OAM configuration or pre-configuration.

[0089] In some embodiments of step 42, the NTN network device can obtain indication information based on the handover configuration of the TNL link. The indication information is used to indicate the handover configuration of the TNL link. The indication information may include any information capable of indicating the handover configuration. For example, the NTN network device can obtain the handover configuration of the TNL link as the indication information. Thus, the indication information may include the handover configuration of the TNL link. As another example, the NTN network device can obtain identification information capable of identifying the handover configuration of the TNL link as the indication information. Thus, the indication information may include identification information used to identify the handover configuration of the TNL link.

[0090] The indication information can indicate the handover type of the first TNL link. The handover type can be selected from hard handover and soft handover.

[0091] As an example, the indication information may indicate that the handover type of the first TNL link is a hard handover. For instance, the indication information may include identification information used to identify that the handover type of the first TNL link is a hard handover.

[0092] As another example, the indication information may indicate that the handover type of the first TNL link is a soft handover; it may also indicate a second validity period for the second TNL link. For example, the indication information may include identification information for identifying that the handover type of the first TNL link is a soft handover and a second validity period for the second TNL link. As another example, the indication information may include identification information for identifying that the handover type of the first TNL link is a soft handover and identification information for identifying the second validity period.

[0093] As another example, the indication information may indicate that the handover type of the first TNL link is a hard handover; it may also indicate the first validity period of the first TNL link. For example, the indication information may include identification information for identifying that the handover type of the first TNL link is a hard handover and the first validity period of the first TNL link. As another example, the indication information may include identification information for identifying that the handover type of the first TNL link is a hard handover and identification information for identifying the first validity period.

[0094] As another example, the indication information may indicate that the handover type of the first TNL link is a soft handover; it may also indicate the first validity period of the first TNL link. For example, the indication information may include identification information for identifying that the handover type of the first TNL link is a soft handover and the first validity period of the first TNL link. As another example, the indication information may include identification information for identifying that the handover type of the first TNL link is a soft handover and identification information for identifying the first validity period.

[0095] As another example, the indication information may indicate the handover type of the first TNL link, the first validity period of the first TNL link, and the address of the first TNL link. For example, the indication information may include identification information for identifying the handover type of the first TNL link, the first validity period of the first TNL link, and the address of the first TNL link. As another example, the indication information may include identification information for identifying the handover type of the first TNL link, identification information for identifying the first validity period, and identification information for identifying the address of the first TNL link.

[0096] In some embodiments of step 42, the indication information may be carried by the RAN configuration update message bearer.

[0097] When a feeder link handover occurs, NTN network devices can send a RAN configuration update message to the core network device to update the core network device's configuration. NTN network devices can obtain indication information during a feeder link handover and can add this indication information to the RAN configuration update message, allowing the indication information to be carried by the RAN configuration update message. The core network device, by receiving the RAN configuration update message, can obtain the indication information and thus the handover configuration indicated by the indication information. The core network device can send an acknowledgment message for the RAN configuration update message to the NTN network device. The NTN network device can receive the acknowledgment message for the RAN configuration update message. Optionally, the RAN configuration update message may include the address of the TNL link. When the indication information is carried by the RAN configuration update message, the indication information may not need to indicate the address of the TNL link. For example, the indication information may indicate that the handover type of the first TNL link is a hard handover. Alternatively, the indication information may indicate that the handover type of the first TNL link is a soft handover and the second validity period of the second TNL link. Of course, when the indication information is carried by the RAN configuration update message, the indication information may also indicate the address of the TNL link.

[0098] Therefore, NTN network devices can indicate the handover configuration of TNL links by updating their configurations. By instructing the NTN network devices on the handover configuration of TNL links, the core network devices can automatically update the TNL links on the NG interfaces, ensuring connectivity of the NG interfaces during mobility management. For example, during power supply link handover, the NTN network device can send only one RAN configuration update message to the core network device, instead of sending multiple RAN configuration update messages, thereby reducing the number of signaling interactions between the NTN network devices and the core network devices and lowering the possibility of signaling storms.

[0099] Furthermore, since the core network equipment can automatically update the TNL link of the NG interface according to the handover configuration indicated by the instruction information, it avoids the situation where the NTN network equipment has been disconnected from the gateway station, but the core network equipment has not removed the corresponding TNL link on the NG interface in time, thereby avoiding downlink data transmission failure and ensuring service continuity.

[0100] Indication information can be carried by adding fields to the RAN configuration update message. For example, an indication information field such as "TNL Association valid timer" and / or "TNL Association usage" can be added to the RAN configuration update message. The TNL Association valid timer field carries the validity period of the TNL link. The TNL Association usage field carries the handover type of the TNL link.

[0101] The information elements in the RAN configuration update message can be shown in Table 2 below.

[0102] Table 2

[0103]

[0104] In some embodiments of step 42, the indication information may be carried by an NG Setup Request message.

[0105] The NG Establishment Request message is used to establish an NG connection between NTN network devices and core network devices. See also... Figure 6When an NTN network device moves into the service range of a core network device and needs to establish an NG connection, it can send an NG setup request message to the core network device. The NG setup request message includes the NTN network device identifier, PLMN identifier, configured tracking area, access type, and default paging DRX, etc. The core network device can establish an NG connection with the NTN network device based on the NG setup request message; it can also send an NG setup response message to the NTN network device.

[0106] When an NTN network device moves into the service range of a core network device and needs to establish an NG connection with the core network device, it can obtain indication information; this indication information can be added to the NG establishment request message. This allows the indication information to be carried by the NG establishment request message. The core network device can establish a connection with the NTN network device based on the NG establishment request message. The core network device can obtain the indication information from the NG establishment request message, thereby obtaining the handover configuration of the TNL link. The core network device can send an NG establishment response message to the NTN network device. The NTN network device can receive the NG establishment response message. Optionally, when the indication information is carried by the NG establishment request message, the indication information can indicate the handover type of the first TNL link, the first valid time of the first TNL link, and the address of the first TNL link. This handover type is selected from hard handover and soft handover.

[0107] Therefore, NTN network devices can indicate the handover configuration of TNL links through connection establishment. By indicating the handover configuration of TNL links on the NTN network device side, the core network device can automatically update the TNL links on the NG interface, ensuring the connection of the NG interface during mobility management. For example, the NTN network device does not need to send RAN configuration update messages to the core network device, thereby reducing the number of signaling interactions between the NTN network device and the core network device.

[0108] Furthermore, since the core network equipment can automatically update the TNL link of the NG interface according to the handover configuration indicated by the instruction information, it avoids the situation where the NTN network equipment has been disconnected from the gateway station, but the core network equipment has not removed the corresponding TNL link on the NG interface in time, thereby avoiding downlink data transmission failure and ensuring service continuity.

[0109] Indicative information can be carried by adding fields to the NG establishment request message. For example, an indication information field such as "TNL Association valid timer" and / or "TNL Association usage" can be added to the NG establishment request message. The TNL Association valid timer field carries the validity period of the TNL link. The TNL Association usage field carries the handover type of the TNL link.

[0110] The information elements in the NG setup request message can be shown in Table 3 below.

[0111] Table 3

[0112]

[0113] In some embodiments, the core network device can update the availability status of TNL links based on indication information. For example, the core network device can add and / or remove TNL links on the NG interface according to the handover configuration indicated by the indication information, thereby updating the availability status of the TNL links. The NG interface is the interface between the NTN network device and the core network device.

[0114] The available states of a TNL link include connected and disconnected states. A connected TNL link can be used for data transmission, while a disconnected TNL link cannot be used for data transmission. Core network equipment can determine which TNL links are in the connected state based on the handover configuration and can add connected TNL links to NG interfaces; conversely, it can determine which TNL links are in the disconnected state based on the handover configuration and can remove disconnected TNL links from NG interfaces.

[0115] Core network devices can add TNL link addresses to the NG interface configuration to add TNL links to the NG interface; they can also remove TNL link addresses from the NG interface configuration to remove TNL links from the NG interface.

[0116] As an example, the indication information is used to indicate that the handover type of the first TNL link is a hard handover. Based on the indication information, the core network device can determine that the first TNL link is connected and that the existing second TNL link between the core network device and the NTN network device is disconnected; it can add the first TNL link and remove the second TNL link on the NG interface. Upon receiving the indication information, the core network device can immediately add the first TNL link and remove the second TNL link on the NG interface or within a short set time. The core network device can remove the second TNL link on the NG interface first and then add the first TNL link. Alternatively, the core network device can add the first TNL link on the NG interface first and then remove the second TNL link. The addition of the first TNL link and the removal of the second TNL link can be performed simultaneously.

[0117] As another example, the indication information is used to indicate that the handover type of the first TNL link is a soft handover and the second validity period of the second TNL link. Based on the indication information, the core network device can determine that the first TNL link is in a connected state, and that the existing second TNL link between the core network device and the NTN network device is in a connected state; it can add the first TNL link to the NG interface, or keep the second TNL link on the NG interface unchanged. For example, the core network device can add the first TNL link to the NG interface immediately or within a short set time after receiving the indication information.

[0118] In addition, the core network equipment can determine, based on the indication information, that the second TNL link is disconnected after the second valid time ends; and can remove the second TNL link on the NG interface after the second valid time ends.

[0119] As another example, the indication information is used to indicate that the handover type of the first TNL link is a hard handover and the first valid time of the first TNL link. Based on the indication information, the core network device can determine that the first TNL link is connected after the first valid time has elapsed, and that the existing second TNL link between the core network device and the NTN network device is disconnected after the first valid time has elapsed; it can add the first TNL link on the NG interface and remove the existing second TNL link between the core network device and the NTN network device after the first valid time has elapsed. The core network device can add the first TNL link on the NG interface immediately or within a short set time after the first valid time has elapsed, and remove the second TNL link.

[0120] In addition, the core network equipment can determine, based on the indication information, that the first TNL link is disconnected after the first effective time ends; and can remove the first TNL link on the NG interface after the first effective time ends.

[0121] As another example, the indication information is used to indicate that the handover type of the first TNL link is a soft handover and the first valid time of the first TNL link. Based on the indication information, the core network device can determine that the first TNL link is in a connected state after the first valid time has elapsed, and that the existing second TNL link between the core network device and the NTN network device is in a connected state after the first valid time has elapsed; it can add the first TNL link to the NG interface after the first valid time has elapsed, or it can keep the second TNL link on the NG interface unchanged. The core network device can add the first TNL link to the NG interface immediately or within a short set time after the first valid time has elapsed.

[0122] In addition, the core network equipment can determine that the first TNL link is disconnected after the first effective time ends based on the indication information, and can remove the first TNL link on the NG interface after the first effective time ends.

[0123] The valid time includes one or more of the following: start time, disconnection time, and connection period. Reaching the valid time can refer to reaching the start time or entering the connection period. The end of the valid time can refer to reaching the disconnection time or leaving the connection period.

[0124] In some embodiments, when downlink data needs to be transmitted, the core network device can select a target TNL link based on its availability; the target TNL link can then be used to transmit downlink data to the NTN network device. The NTN network device can receive the downlink data. Similarly, when uplink data needs to be transmitted, the NTN network device can also select a target TNL link; the target TNL link can then be used to transmit uplink data to the core network device. The core network device can receive the uplink data.

[0125] The target TNL link is a TNL link that is in a connected state. Core network equipment can select the target TNL link from the TNL links on the NG interface. For soft handover, there can be one or more TNL links on the NG interface. The core network equipment can select one of these TNL links as the target TNL link. For hard handover, there is only one TNL link on the NG interface. The core network equipment can select this TNL link as the target TNL link.

[0126] NTN network devices can select a target TNL link from the TNL links supported by the connected gateway station. The TNL links supported by the gateway station can be those supported by the corresponding feeder link. The target TNL link is a TNL link that is currently connected. For soft handover, an NTN network device can connect to one or more gateway stations that support one or more TNL links. The NTN network device can select one of these TNL links as the target TNL link. For hard handover, an NTN network device can connect to a single gateway station that supports one TNL link. The NTN network device can select this TNL link as the target TNL link.

[0127] As an example, the indication information is used to indicate that the handover type of the first TNL link is a hard handover. The core network equipment can add the first TNL link and remove the second TNL link on the NG interface based on the indication information.

[0128] When downlink data needs to be sent, the core network device can select the first TNL link as the target TNL link and use the target TNL link to send downlink data to the NTN network device. When uplink data needs to be sent, the NTN network device can select the first TNL link as the target TNL link and use the target TNL link to send uplink data to the core network device.

[0129] As another example, the indication information is used to indicate that the handover type of the first TNL link is a soft handover and the second validity period of the second TNL link. The core network equipment can add the first TNL link on the NG interface according to the indication information, and remove the second TNL link from the NG interface after the second validity period ends.

[0130] During the second valid time period of the second TNL link, the core network device can select the first TNL link and / or the second TNL link as the target TNL link; it can use the target TNL link to send downlink data to the NTN network device. During the second valid time period of the second TNL link, the NTN network device can select the first TNL link and / or the second TNL link as the target TNL link; it can use the target TNL link to send uplink data to the core network device. After the second valid time period of the second TNL link ends, the core network device can select the first TNL link as the target TNL link; it can use the target TNL link to send downlink data to the NTN network device. After the second valid time period of the second TNL link ends, the NTN network device can select the first TNL link as the target TNL link; it can use the target TNL link to send uplink data to the core network device.

[0131] As another example, the indication information is used to indicate that the handover type of the first TNL link is a hard handover and the first valid time of the first TNL link. The core network equipment can, according to the indication information, add the first TNL link and remove the second TNL link on the NG interface after the first valid time has elapsed, and remove the first TNL link from the NG interface after the first valid time has ended.

[0132] During the first valid time of the first TNL link, the core network device can select the first TNL link as the target TNL link and use the target TNL link to send downlink data to the NTN network device; the NTN network device can select the first TNL link as the target TNL link and use the target TNL link to send uplink data to the core network device.

[0133] As another example, the indication information is used to indicate that the handover type of the first TNL link is a soft handover and the first valid time of the first TNL link. The core network equipment can, according to the indication information, add the first TNL link on the NG interface after the first valid time has elapsed, and remove the first TNL link from the NG interface after the first valid time has ended.

[0134] During the first valid time of the first TNL link, the core network device can select the first TNL link and / or the second TNL link as the target TNL link and can use the target TNL link to send downlink data to the NTN network device; the NTN network device can select the first TNL link and / or the second TNL link as the target TNL link and can use the target TNL link to send uplink data to the core network device. The following describes several scenario examples of embodiments of this specification.

[0135] Example scenario 1.

[0136] In Scenario Example 1, NTN network devices can indicate the switching configuration of TNL links by updating the configuration.

[0137] Please see Figure 7 Example scenario one illustrates a soft handover process.

[0138] NTN network devices connect to a second gateway station. The physical link between the NTN network devices and the second gateway station is a second feeder link. The second feeder link supports a second TNL link. The second gateway station has the address of the second TNL link pre-configured. The NTN network devices can obtain the address of the second TNL link through the second gateway station; they can establish an SCTP connection through the address of the second TNL link. Core network devices can use the second TNL link to send downlink data to NTN network devices. For example, core network devices can send downlink data to the second gateway station, and the second gateway station can receive and send downlink data to the NTN network devices. NTN network devices can use the second TNL link to send uplink data to core network devices. For example, NTN network devices can send uplink data to the second gateway station, and the second gateway station can receive and send uplink data to the core network devices.

[0139] Due to the movement of the NTN network device, it connects to the first gateway station. The physical link between the NTN network device and the first gateway station is the first feeder link. The first feeder link supports the first TNL link. The first gateway station is pre-configured with the address of the first TNL link. The NTN network device can obtain the address of the first TNL link through the first gateway station; it can establish an SCTP connection through the address of the first TNL link. The handover type pre-configured for the first TNL link is soft handover. At this time, the NTN network device simultaneously maintains the SCTP connection corresponding to the second TNL link and the SCTP connection corresponding to the first TNL link. Based on the second TNL link and the first TNL link, the NTN network device can use multiple different paths to send uplink data.

[0140] NTN network devices can determine the second validity period of the second TNL link and generate indication information. This indication information indicates that the handover type of the first TNL link is a soft handover and the second validity period of the second TNL link. NTN network devices can send RAN configuration update messages to core network devices. For example, NTN network devices can send RAN configuration update messages using either the second or first TNL link. Core network devices can receive RAN configuration update messages and can send acknowledgment messages for the RAN configuration update messages to NTN network devices. The indication information can be carried by the RAN configuration update message. Core network devices can obtain the indication information from the RAN configuration update message; based on the indication information, they can add a first TNL link to the NG interface while keeping the existing second TNL link on the NG interface unchanged. For example, the RAN configuration update message includes the address of the first TNL link. Core network devices can add the address of the first TNL link to the NG interface. At this time, the NG interface has both a first TNL link and a second TNL link. The core network device considers the first and second TNL links to be connected. Based on the second and first TNL links, the core network device can send downlink data through multiple different paths.

[0141] NTN network equipment and core network equipment can perform PDU (Protocol Data Unit) session modification for the UE (User Equipment) of the current serving cell in preparation for user plane data transmission.

[0142] After the second valid time of the second TNL link expires, the core network device considers the connection between the NTN network device and the second gateway station to be disconnected, and the second TNL link is in a disconnected state. Therefore, the core network device can remove the second TNL link from the NG interface. For example, the core network device can remove the address of the second TNL link from the NG interface. At this time, the first TNL link is configured on the NG interface, and the second TNL link is no longer configured. The core network device sends downlink data through the first TNL link. For example, the core network device can send downlink data to the first gateway station. The first gateway station can receive and send downlink data to the NTN network device.

[0143] In Scenario Example 1, the NTN network device sends a RAN configuration update message carrying indication information to the core network device, enabling the core network device to know that the handover type of the first TNL link is soft handover and the second validity period of the second TNL link. During the second validity period of the second TNL link, the core network device considers both the first and second TNL links to be connected and can send downlink data through the second TNL link and / or the first TNL link. After the second validity period of the second TNL link ends, the core network device considers the second TNL link to be disconnected and can send downlink data through the first TNL link. Thus, by sending a single RAN configuration update message to the core network device, the NTN network device enables the core network device to automatically add the first TNL link and remove the second TNL link on the NG interface, maintaining the NG interface functionality between the NTN network device and the core network device. NTN network devices do not need to send separate RAN configuration update messages to the core network devices for adding the first TNL link and for removing the second TNL link. This reduces the number of signaling interactions between NTN network devices and core network devices, lowers the likelihood of signaling storms, and also reduces service transmission latency.

[0144] Scenario Example 2.

[0145] In Scenario Example 2, NTN network devices can indicate the switching configuration of TNL links by updating their configurations.

[0146] Please see Figure 8 Scenario Example 2 illustrates a hard handover process.

[0147] NTN network devices connect to a second gateway station. The physical link between the NTN network devices and the second gateway station is a second feeder link. The second feeder link supports a second TNL link. The second gateway station has the address of the second TNL link pre-configured. The NTN network devices can obtain the address of the second TNL link through the second gateway station; they can establish an SCTP connection through the address of the second TNL link. Core network devices can use the second TNL link to send downlink data to NTN network devices. For example, core network devices can send downlink data to the second gateway station, and the second gateway station can receive and send downlink data to the NTN network devices. NTN network devices can use the second TNL link to send uplink data to core network devices. For example, NTN network devices can send uplink data to the second gateway station, and the second gateway station can receive and send uplink data to the core network devices.

[0148] Due to the movement of the NTN network device, it connects to the first gateway station. The physical link between the NTN network device and the first gateway station is the first feeder link. The first feeder link supports the first TNL link. The first gateway station is pre-configured with the address of the first TNL link. The NTN network device obtains the address of the first TNL link through the first gateway station; it can establish an SCTP connection using the address of the first TNL link. The handover type pre-configured for the first TNL link is hard handover. The NTN network device can disconnect from the second gateway station. At this time, the NTN network device maintains the SCTP connection corresponding to the first TNL link but does not maintain the SCTP connection corresponding to the second TNL link. The NTN network device uses the first TNL link to send uplink data.

[0149] NTN network devices can generate indication information. This indication information indicates that the handover type of the first TNL link is a hard handover. NTN network devices can send RAN configuration update messages to core network devices. For example, an NTN network device can use the first TNL link to send a RAN configuration update message. Core network devices can receive RAN configuration update messages and can send RAN configuration update message acknowledgments to the NTN network device. The indication information can be carried by the RAN configuration update message. Core network devices can obtain the indication information from the RAN configuration update message; based on the indication information, they can add a first TNL link and remove a second TNL link on the NG interface. For example, the RAN configuration update message includes the address of the first TNL link. The core network device can add the address of the first TNL link to the NG interface. At this time, the first TNL link is configured on the NG interface, and the second TNL link is no longer configured. Core network devices send downlink data through the first TNL link. For example, a core network device can send downlink data to a first gateway station. The first gateway station can receive and send downlink data to the NTN network device.

[0150] NTN network equipment and core network equipment can perform PDU (Protocol Data Unit) session modification for the UE (User Equipment) of the current serving cell in preparation for user plane data transmission.

[0151] In Scenario Example 2, the NTN network device sends a RAN configuration update message carrying indication information to the core network device, enabling the core network device to know that the handover type of the first TNL link is a hard handover. Based on the indication information, the core network device can determine that the first TNL link is connected and the second TNL link is disconnected. Therefore, by sending a single RAN configuration update message to the core network device, the NTN network device enables the core network device to automatically add the first TNL link and remove the second TNL link on the NG interface, thus maintaining the NG interface functionality between the NTN network device and the core network device. The NTN network device does not need to send separate RAN configuration update messages for adding the first TNL link and removing the second TNL link to the core network device, thereby reducing the number of signaling interactions between the NTN network device and the core network device, lowering the possibility of signaling storms, and also reducing service transmission latency.

[0152] In addition, after receiving the RAN configuration update message carrying indication information, the core network equipment automatically removes the second TNL link on the NG interface to stop sending data to the second gateway station. This prevents the core network equipment from sending downlink data to the second gateway station when the NTN network equipment is disconnected from the second gateway station, thus avoiding downlink data transmission failure.

[0153] Scenario Example 3.

[0154] In Scenario Example 3, NTN network devices can indicate the switching configuration of TNL links by establishing a connection.

[0155] In non-terrestrial networks, NTN network devices exhibit high dynamism. The movement characteristics of NTN network devices are predictable. The connections between NTN network devices and gateway stations are predetermined. NTN network devices know which one or more gateway stations they are connected to. Furthermore, gateway stations are connected to core network equipment. Core network equipment is aware of the gateway stations it connects to. The IP address and location information of the gateway stations do not change. Gateway station information and core network equipment information can be pre-sent to the NTN network devices. For example, this can be done through OAM (Operation Administration and Maintenance) configuration or pre-configuration. Based on one or more of its own movement trajectory, gateway station information, and core network equipment information, the NTN network device can determine a potentially future TNL link as its first TNL link. Potentially future TNL links may include TNL links supported by gateway stations that the NTN network device may connect to in the future.

[0156] NTN network devices can obtain the handover configuration of each first TNL link; they can also obtain indication information based on the handover configuration of each first TNL link. The indication information is used to indicate the handover configuration of each first TNL link. The handover configuration of the first TNL link can be pre-configured, or it can be calculated based on a pre-configured configuration. The handover configuration of the first TNL link can include at least one of the following: the handover type of the first TNL link, the first validity period of the first TNL link, and the address of the first TNL link. The indication information can indicate the handover type of each first TNL link, the first validity period of each first TNL link, and the address of each first TNL link.

[0157] When an NTN network device moves into the service range of a core network device and needs to establish an NG connection, it can add indication information to the NG establishment request message. This allows the indication information to be carried by the NG establishment request message; the NTN network device can send an NG establishment request message to the core network device. The core network device establishes a connection with the NTN network device based on the NG establishment request message. The core network device then sends an NG establishment response message to the NTN network device. The NTN network device receives the NG establishment response message.

[0158] The core network device can obtain indication information from the NG establishment request message and update the availability status of the TNL link based on the indication information. For example, the core network device can add and / or remove TNL links on the NG interface according to the handover configuration indicated by the indication information. The NG interface is the interface between the NTN network device and the core network device. For each first TNL link, after the first validity time of the first TNL link has elapsed, if the handover type of the first TNL link is a hard handover, the core network device can add the first TNL link on the NG interface and remove the existing second TNL link between the core network device and the NTN network device; if the handover type of the first TNL link is a soft handover, the core network device can add the first TNL link on the NG interface and keep the existing second TNL link between the core network device and the NTN network device unchanged. In addition, for each first TNL link, after the first validity time of the first TNL link has expired, the core network device can remove the first TNL link on the NG interface.

[0159] When downlink data needs to be transmitted, core network devices can select a target TNL link from the TNL links configured on the NG interface; they can then use the target TNL link to transmit downlink data to NTN network devices. NTN network devices can receive downlink data. For soft handover, the NG interface can have one or more TNL links. The core network device can select one of these TNL links as the target TNL link. For hard handover, the NG interface has only one TNL link. The core network device can select this TNL link as the target TNL link.

[0160] When uplink data needs to be transmitted, NTN network devices can select a target TNL link from the TNL links supported by the connected gateway station; they can then use the target TNL link to send uplink data to core network devices. Core network devices can receive uplink data. For soft handover, NTN network devices can connect to one or more gateway stations that support one or more TNL links. The NTN network device can select one of these TNL links as the target TNL link. For hard handover, NTN network devices can connect to a gateway station that supports one TNL link. The NTN network device can select this TNL link as the target TNL link.

[0161] In Scenario Example 3, the NTN network device can indicate the handover configuration of the TNL link through connection establishment. By indicating the handover configuration of the TNL link on the NTN network device side, the core network device can automatically update the TNL link on the NG interface, ensuring the connection of the NG interface during mobility management. For example, the NTN network device does not need to send RAN configuration update messages to the core network device, thereby reducing the number of signaling interactions between the NTN network device and the core network device.

[0162] Furthermore, since the core network equipment can automatically update the TNL link of the NG interface according to the indicated switching configuration, it avoids the situation where the NTN network equipment has been disconnected from the gateway station but the core network equipment has not removed the corresponding TNL link on the NG interface in time, thereby avoiding downlink data transmission failure and ensuring service continuity.

[0163] The above description only illustrates the steps or processes related to the embodiments of this specification, but the embodiments of this specification are not limited thereto. The methods in the embodiments of this specification may also include other steps or processes, and for details of these steps or processes, please refer to related technologies. In addition, the above embodiments are only exemplary descriptions of the embodiments of this specification, but this specification is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0164] This specification also provides another mobility management method in its embodiments. This mobility management method can be applied to core network equipment. Please refer to... Figure 5 and Figure 9 The mobility management method may include the following steps.

[0165] Step 91: Receive indication information from the NTN network device, the indication information being used to indicate the switching configuration of the TNL link.

[0166] Step 92: Update the availability status of the TNL link according to the instruction information.

[0167] Core network equipment can receive indication information from NTN network equipment. This indication information is used to indicate the handover configuration of TNL links. By indicating the handover configuration of TNL links on the NTN network equipment side, the availability status of TNL links can be indicated, enabling the core network equipment to update the TNL links on the NG interface itself, ensuring connectivity of the NG interface during mobility management. This reduces the number of signaling interactions on the NG interface (e.g., the NG-C interface) and also lowers service transmission latency. For example, the NTN network equipment does not need to send separate RAN configuration update messages to the core network equipment for adding a new TNL link (e.g., the first TNL link) and for removing an old TNL link (e.g., the second TNL link), thereby reducing the number of signaling interactions between the NTN network equipment and the core network equipment and lowering service transmission latency.

[0168] In some embodiments, the NTN network device can determine the TNL link; obtain the handover configuration of the TNL link; and obtain indication information based on the handover configuration of the TNL link. The indication information is used to indicate the handover configuration of the TNL link.

[0169] NTN network devices can identify one or more first TNL links. A first TNL link is a newly added TNL link between the core network device and the NTN network device. NTN network devices can also identify one or more second TNL links. Second TNL links are existing TNL links between the core network device and the NTN network device.

[0170] The handover configuration of a TNL link includes at least one of the following: the handover type of the first TNL link, the first validity period of the first TNL link, the address of the first TNL link, the second validity period of the second TNL link, and the address of the second TNL link.

[0171] In some embodiments of step 91, the indication information may be carried by a RAN Configuration Update message. The core network device can receive the RAN Configuration Update message carrying the indication information to obtain the indication information.

[0172] In some embodiments of step 91, the indication information may be carried by an NG Setup Request message. The core network device can receive the NG Setup Request message carrying the indication information to obtain the indication information.

[0173] In some embodiments of step 92, the core network device can update the availability status of the TNL link based on the indication information. For example, the core network device can add or remove a TNL link on the NG interface according to the handover configuration indicated by the indication information, thereby updating the availability status of the TNL link. The NG interface is the interface between the NTN network device and the core network device.

[0174] As an example, the indication information is used to indicate that the handover type of the first TNL link is a hard handover. The core network equipment can add the first TNL link and remove the second TNL link on the NG interface based on the indication information.

[0175] As another example, the indication information is used to indicate that the handover type of the first TNL link is a soft handover and the second validity period of the second TNL link. Based on the indication information, the core network equipment can add the first TNL link to the NG interface while keeping the second TNL link on the NG interface unchanged; it can also remove the second TNL link from the NG interface after the second validity period ends.

[0176] As another example, the indication information is used to indicate that the handover type of the first TNL link is a hard handover and the first valid time of the first TNL link. Based on the indication information, the core network device can add the first TNL link on the NG interface and remove the existing second TNL link between the core network device and the NTN network device after the first valid time has elapsed; it can also remove the first TNL link on the NG interface after the first valid time has ended.

[0177] As another example, the indication information is used to indicate that the handover type of the first TNL link is a soft handover and the first validity period of the first TNL link. Based on the indication information, the core network device can add the first TNL link on the NG interface after the first validity period has elapsed, while maintaining the existing second TNL link between the core network device and the NTN network device on the NG interface; or it can remove the first TNL link from the NG interface after the first validity period has ended.

[0178] In some embodiments, when downlink data needs to be transmitted, the core network device can select a target TNL link based on its availability; the target TNL link can then be used to transmit downlink data to the NTN network device. The NTN network device can receive the downlink data. Similarly, when uplink data needs to be transmitted, the NTN network device can also select a target TNL link; the target TNL link can then be used to transmit uplink data to the core network device. The core network device can receive the uplink data.

[0179] The target TNL link is a TNL link that is in a connected state. Core network devices can select the target TNL link from the TNL links configured on the NG interface. For soft handover, there can be one or more TNL links on the NG interface. The core network device can select one of these TNL links as the target TNL link. For hard handover, there is only one TNL link on the NG interface. The core network device can select this TNL link as the target TNL link.

[0180] The above description only illustrates the steps or processes related to the embodiments of this specification, but the embodiments of this specification are not limited thereto. The methods in the embodiments of this specification may also include other steps or processes, and for details of these steps or processes, please refer to related technologies. In addition, the above embodiments are only exemplary descriptions of the embodiments of this specification, but this specification is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0181] for Figure 9 In the corresponding embodiments, and Figure 4 For the parts that are the same as those in the corresponding embodiments, please refer to Figure 4 The descriptions in the corresponding embodiments will not be repeated here.

[0182] This specification also provides another mobility management method in its embodiments. This mobility management method can be applied to a first NTN network device. Please refer to... Figure 10 and Figure 11 The mobility management method may include the following steps.

[0183] Step 101: Determine the TNL link of the first NTN network device.

[0184] Step 102: Send indication information to the second NTN network device. The indication information is used to indicate the switching configuration of the TNL link.

[0185] The first NTN network device can determine its own TNL links and can send indication information to the second NTN network device. This indication information is used to indicate the handover configuration of the TNL links. By indicating the handover configuration of the TNL links, the availability status of the TNL links can be indicated. This allows the second NTN network device to know the availability status of the TNL links between the first NTN network device and the core network device, thus enabling it to independently select the data transmission path with the core network device and ensuring the connection of the second NTN network device's NG interface during mobility management. This reduces the number of signaling interactions on the NG interface corresponding to the second NTN network device, thereby reducing service transmission latency. For example, the second NTN network device does not need to send separate RAN configuration update messages for adding new TNL links and for removing old TNL links to the core network device, thus reducing the number of signaling interactions between the second NTN network device and the core network device.

[0186] In some embodiments, the first NTN network device and the second NTN network device can communicate with each other. The second NTN network device can also communicate with the core network device. Therefore, the second NTN network device can communicate with the core network device through the first NTN network device. See also... Figure 12a The first NTN network device and the second NTN network device can communicate via the Xn interface. The second NTN network device and the core network device can communicate via the NG interface. Please refer to [link / reference]. Figure 12b During the movement of the second NTN network device, if the connection between the second NTN network device and the core network device is lost, but the first NTN network device and the gateway station remain connected, the second NTN network device can maintain the connection of the NG interface between the second NTN network device and the core network device through the connection between the second NTN network device and the first NTN network device and the gateway station, thus ensuring that the NG interface of the RNL remains connected.

[0187] The second NTN network device can send uplink data to the core network device through the first NTN network device. For example, the second NTN network device can send uplink data to the first NTN network device, and the first NTN network device can receive and send uplink data to the core network device. The core network device can send downlink data to the second NTN network device through the first NTN network device. For example, the core network device can send downlink data to the first NTN network device, and the first NTN network device can receive and send downlink data to the second NTN network device. Thus, the first NTN network device can forward data between the second NTN network device and the core network device, thereby realizing data transmission between the second NTN network device and the core network device.

[0188] In some embodiments of step 101, the first NTN network device may determine the TNL link when it needs to send an Xn message to the second NTN network device. Alternatively, the first NTN network device may determine the TNL link in advance before it needs to send an Xn message to the second NTN network device. The Xn message includes a message about the Xn interface.

[0189] For example, the Xn message includes the Xn Setup message. The Xn Setup message is used to establish a connection between NTN network devices. The first NTN network device can determine the TNL link when it needs to establish a connection with the second NTN network device. Alternatively, the first NTN network device can pre-determine the TNL link before establishing a connection with the second NTN network device. Indication information is carried by the Xn Setup message. Thus, the first NTN network device indicates the switching configuration of the TNL link through connection establishment.

[0190] For example, Xn messages include non-Xn establishment messages, such as RAN paging messages. The first NTN network device can determine the TNL link when a non-Xn establishment message needs to be sent. Indication information can be carried by the non-Xn establishment message. Therefore, the first NTN network device can indicate the handover configuration of the TNL link through the non-Xn establishment message.

[0191] In some embodiments of step 101, the first NTN network device may identify one or more first TNL links. A first TNL link is a newly added TNL link between the core network device and the first NTN network device. A first TNL link may be a TNL link for which a communication connection has not yet been established, or it may be a TNL link for which a communication connection has been established but has not yet been used for data transmission.

[0192] The first NTN network device is highly dynamic. Its movement characteristics are predictable. The connection between the first NTN network device and the gateway station can be predetermined. The first NTN network device knows which one or more gateway stations it is connected to. Furthermore, the gateway station is connected to the core network equipment. The core network equipment knows the gateway stations it is connected to. The IP address and location information of the gateway station do not change. Gateway station information and core network equipment information can be pre-sent to the first NTN network device. For example, this can be done through OAM (Operation Administration and Maintenance) configuration or pre-configuration. The first NTN network device can determine a potentially future TNL link as the first TNL link based on one or more of its own movement trajectory, gateway station information, and core network equipment information. Potentially future TNL links may include TNL links supported by gateway stations that the first NTN network device may connect to in the future. For example, the first NTN network device may include a satellite-based base station. The satellite-borne base station determines the TNL link that may be established in the future as the first TNL link based on one or more of its own motion trajectory, ephemeris information, gateway station information, core network equipment information, etc.

[0193] In some embodiments of step 102, the first NTN network device can obtain the handover configuration of the TNL link; it can also obtain indication information based on the handover configuration of the TNL link. The indication information is used to indicate the handover configuration of the TNL link.

[0194] The handover configuration of the TNL link can be pre-configured, or it can be calculated based on a pre-configured configuration. The TNL link handover configuration may include at least one of the following: the handover type of the first TNL link, the first valid time of the first TNL link, the address of the first TNL link, and the functional identification information of the first NTN network device. The functional identification information of the first NTN network device is used to indicate whether the first NTN network device supports NG transmission for multi-NTN network device communication. For example, the functional identification information of the first NTN network device is used to indicate that the first NTN network device supports NG transmission for multi-NTN network device communication. The functional identification information can be pre-configured.

[0195] The indication information may include any information capable of indicating the handover configuration. The indication information may include the handover configuration of the TNL link. Alternatively, the indication information may include identification information used to identify the handover configuration of the TNL link.

[0196] The indication information can indicate the handover type of the first TNL link. As an example, the indication information can indicate that the handover type of the first TNL link is a hard handover; it can also indicate the first validity period of the first TNL link. As another example, the indication information can indicate that the handover type of the first TNL link is a soft handover; it can also indicate the first validity period of the first TNL link. As yet another example, the indication information can indicate the handover type of the first TNL link, the first validity period of the first TNL link, the address of the first TNL link, and the functional identification information of the first NTN network device.

[0197] In some embodiments of step 102, the indication information can be carried by an Xn message. The Xn message may include messages from the Xn interface. The Xn message may include an Xn Setup message. The Xn Setup message is used to establish a connection between NTN network devices. The Xn message may also include non-Xn Setup messages, such as RAN Paging messages. The first NTN network device can obtain the indication information when it needs to send an Xn message to the second NTN network device; it can add the indication information to the Xn message, allowing the indication information to be carried by the Xn message. The second NTN network device can receive the Xn message; it can obtain the indication information from the Xn message, thereby obtaining the TNL link handover configuration. The second NTN network device can send a response message for the Xn message to the first NTN network device. The first NTN network device can receive the response message for the Xn message.

[0198] For example, the first NTN network device can obtain indication information when it needs to establish a connection with the second NTN network device; it can add the indication information to the Xn Setup message. This allows the indication information to be carried by the Xn Setup message. The second NTN network device can establish a connection with the first NTN network device based on the Xn Setup message. The second NTN network device can obtain the indication information from the Xn Setup message. The second NTN network device can send a response message to the first NTN network device for the Xn Setup message. Thus, the first NTN network device can indicate the TNL link handover configuration through connection establishment.

[0199] For example, the first NTN network device can obtain indication information when it needs to send a non-Xn establishment message; it can also add the indication information to the non-Xn establishment message, allowing the indication information to be carried by the non-Xn establishment message. The second NTN network device can receive the non-Xn establishment message; it can also obtain the indication information from the non-Xn establishment message. The second NTN network device can send a response message for the non-Xn establishment message to the first NTN network device. The first NTN network device can receive the response message for the non-Xn establishment message. Therefore, the first NTN network device can indicate the handover configuration of the TNL link through the non-Xn establishment message.

[0200] Indication information can be carried by adding fields to the Xn message. For example, an indication information field such as "TNL Association valid timer" and / or "TNL Association usage" can be added to the Xn message. The TNL Association valid timer field carries the validity period of the TNL link. The TNL Association usage field carries the handover type of the TNL link.

[0201] In some embodiments, the second NTN network device can determine the availability status of the TNL link on the first NTN network device side based on indication information. When uplink data needs to be transmitted, the second NTN network device can select a target TNL link based on the availability status of the TNL link on the first NTN network device side; it can then use the target TNL link to transmit uplink data to the core network device via the first NTN network device. The core network device can receive the uplink data. For example, the second NTN network device can transmit uplink data to the first NTN network device. The first NTN network device can receive and use the target TNL link to transmit uplink data to the core network device. For example, the second NTN network device can transmit uplink data and link identification information for identifying the target TNL link to the first NTN network device. The first NTN network device can use the target TNL link corresponding to the link identification information to transmit uplink data to the core network device. For example, the first NTN network device can transmit uplink data to the gateway station corresponding to the target TNL link, and the gateway station can receive and transmit uplink data to the core network device. The link identification information includes any information that can identify a TNL link. For example, the link identification information can be the name or number of the TNL link.

[0202] The availability of a TNL link can include a connected state and a disconnected state. A connected TNL link can be used for data transmission, while a disconnected TNL link cannot be used for data transmission. The second NTN network device can determine the connected and disconnected TNL links based on the handover configuration indicated by the indication information. When uplink data needs to be sent, the second NTN network device can select the target TNL link from the connected TNL links.

[0203] For soft handover, there are one or more TNL links in the connected state. The second NTN network device can select the target TNL link from these one or more TNL links. For hard handover, there is one TNL link in the connected state. The second NTN network device can select this TNL link as the target TNL link.

[0204] For each first TNL link, under the condition that the handover type of the first TNL link is a hard handover, the second NTN network device can determine that the first TNL link is in a connected state during the first effective time of the first TNL link and that the existing second TNL link between the first NTN network device and the core network device is in a disconnected state; it can then select the first TNL link as the target TNL link. Please refer to [link to NTN network device]. Figure 13 For each first TNL link, under the condition that the handover type of the first TNL link is soft handover, the second NTN network device can determine that the first TNL link is in a connected state during the first effective time of the first TNL link and that the existing second TNL link between the first NTN network device and the core network device is also in a connected state; it can select the first TNL link and / or the second TNL link as the target TNL link.

[0205] In some embodiments, the first NTN network device can also send indication information to the core network device. The indication information can be carried by an NG establishment request message or a RAN configuration update message. The core network device can update the availability status of the TNL link based on the indication information. For example, the core network device can update the availability status of the TNL link by adding or removing a TNL link on the NG interface according to the handover configuration indicated by the indication information. The NG interface is the interface between the NTN network device and the core network device. When downlink data needs to be transmitted, the core network device can select a target TNL link based on its availability status; it can then use the target TNL link to transmit downlink data to the second NTN network device. For example, the core network device can use the target TNL link to transmit downlink data to the first NTN network device; the first NTN network device can receive and transmit downlink data to the second NTN network device. The second NTN network device can receive the downlink data.

[0206] The target TNL link is a TNL link that is in a connected state. Core network equipment can select the target TNL link from the TNL links on the NG interface. For soft handover, there can be one or more TNL links on the NG interface. The core network equipment can select one of these TNL links as the target TNL link. For hard handover, there is only one TNL link on the NG interface. The core network equipment can select this TNL link as the target TNL link.

[0207] The above description only illustrates the steps or processes related to the embodiments of this specification, but the embodiments of this specification are not limited thereto. The methods in the embodiments of this specification may also include other steps or processes, and for details of these steps or processes, please refer to related technologies. In addition, the above embodiments are only exemplary descriptions of the embodiments of this specification, but this specification is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0208] for Figure 10 In the corresponding embodiments, and Figure 4 For the parts that are the same as those in the corresponding embodiments, please refer to Figure 4 The descriptions in the corresponding embodiments will not be repeated here.

[0209] This specification also provides another mobility management method in its embodiments. This mobility management method can be applied to a second NTN network device. Please refer to... Figure 11 and Figure 14 The mobility management method may include the following steps.

[0210] Step 141: Receive indication information from the first NTN network device, the indication information being used to indicate the switching configuration of the TNL link.

[0211] Step 142: Determine the availability status of the TNL link based on the indicated information.

[0212] The second NTN network device can receive indication information from the first NTN network device. This indication information is used to indicate the handover configuration of the TNL link. Through this information, the second NTN network device can determine the availability status of the TNL link on the first NTN network device's side, thus allowing it to independently select the data transmission path with the core network device, ensuring the connection of the second NTN network device's NG interface during mobility management. This reduces the number of signaling interactions on the NG interface corresponding to the second NTN network device and also lowers service transmission latency. For example, the second NTN network device does not need to send separate RAN configuration update messages for adding new TNL links and for removing old TNL links to the core network device, thereby reducing the number of signaling interactions between the second NTN network device and the core network device.

[0213] In some embodiments, the first NTN network device can determine the TNL link; obtain the handover configuration of the TNL link; and obtain indication information based on the handover configuration of the TNL link. The indication information is used to indicate the handover configuration of the TNL link.

[0214] The first NTN network device can identify one or more first TNL links. A first TNL link is a newly added TNL link between the core network device and the first NTN network device. The handover configuration of the TNL link includes at least one of the following: the handover type of the first TNL link, the first valid time of the first TNL link, the address of the first TNL link, and the functional identification information of the first NTN network device. The functional identification information of the first NTN network device is used to indicate whether the first NTN network device supports NG transmission for multi-NTN network device communication. For example, the functional identification information of the first NTN network device is used to indicate that the first NTN network device supports NG transmission for multi-NTN network device communication. The functional identification information can be pre-configured.

[0215] The indication information may include any information capable of indicating the handover configuration. For example, the indication information may include the handover configuration itself. Alternatively, the indication information may include identification information used to identify the handover configuration. This identification information may be pre-configured. Or, the identification information may be determined through negotiation between the NTN network device and the core network device.

[0216] In some embodiments, the indication information may be carried by an Xn message. An Xn message may include messages from the Xn interface. An Xn message may include an Xn Setup message. Xn Setup messages are used to establish connections between NTN network devices. Xn messages may also include non-Xn Setup messages, such as RAN Paging messages.

[0217] In some embodiments, the second NTN network device can determine the availability status of the TNL link on the first NTN network device side based on the indication information. When uplink data needs to be transmitted, the second NTN network device can select a target TNL link based on the availability status of the TNL link; it can then use the target TNL link to transmit uplink data to the core network device via the first NTN network device. The core network device can receive the uplink data. For example, the second NTN network device can transmit uplink data to the first NTN network device. The first NTN network device can receive and use the target TNL link to transmit uplink data to the core network device. For example, the second NTN network device can transmit uplink data and link identification information for identifying the target TNL link to the first NTN network device. The first NTN network device can use the target TNL link corresponding to the link identification information to transmit uplink data to the core network device. For example, the first NTN network device can transmit uplink data to the gateway station corresponding to the target TNL link, and the gateway station can receive and transmit uplink data to the core network device. The link identification information includes any information that can identify the TNL link. For example, the link identification information can be the name or number of the TNL link.

[0218] The above description only illustrates the steps or processes related to the embodiments of this specification, but the embodiments of this specification are not limited thereto. The methods in the embodiments of this specification may also include other steps or processes, and for details of these steps or processes, please refer to related technologies. In addition, the above embodiments are only exemplary descriptions of the embodiments of this specification, but this specification is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0219] for Figure 14 In the corresponding embodiments, and Figure 4 For the parts that are the same as those in the corresponding embodiments, please refer to Figure 4 The descriptions in the corresponding embodiments will not be repeated here.

[0220] This specification also provides a mobility management device in its embodiments. This mobility management device may be, for example, an NTN network device, or a component configured within an NTN network device. Figure 4 The contents that are the same as those in the corresponding embodiments will not be repeated.

[0221] Please see Figure 15 The mobility management device may include the following units.

[0222] Determining unit 151 is used to determine the TNL link of the NTN network device;

[0223] The sending unit 152 is used to send indication information to the core network equipment, the indication information being used to indicate the handover configuration of the TNL link.

[0224] This specification also provides another mobility management device in its embodiments. This mobility management device may be, for example, a core network device or a component configured within a core network device. Figure 9 The contents that are the same as those in the corresponding embodiments will not be repeated.

[0225] Please see Figure 16 The mobility management device may include the following units.

[0226] The receiving unit 161 is used to receive indication information from the NTN network device, the indication information being used to indicate the handover configuration of the TNL link;

[0227] The update unit 162 is used to update the availability status of the TNL link according to the indication information.

[0228] This specification also provides another mobility management device in its embodiments. This mobility management device may be, for example, a first NTN network device, or a component configured within the first NTN network device. Figure 10 The contents that are the same as those in the corresponding embodiments will not be repeated.

[0229] Please see Figure 17 The mobility management device may include the following units.

[0230] Determining unit 171 is used to determine the TNL link of the first NTN network device;

[0231] The sending unit 172 is used to send indication information to the second NTN network device, the indication information being used to indicate the switching configuration of the TNL link.

[0232] This specification also provides another mobility management device in its embodiments. This mobility management device may be, for example, a second NTN network device, or a component configured within the second NTN network device. Figure 14 The contents that are the same as those in the corresponding embodiments will not be repeated.

[0233] Please see Figure 18 The mobility management device may include the following units.

[0234] The receiving unit 181 is configured to receive indication information from the first NTN network device, the indication information being used to indicate the handover configuration of the TNL link;

[0235] The determining unit 182 is used to determine the availability status of the TNL link based on the indication information.

[0236] This specification also provides a communication system. This communication system may include NTN network equipment and core network equipment.

[0237] NTN network devices may include a processor and memory, the memory being used to store computer programs that can run on the processor. When the processor executes the computer program, it implements... Figure 4 The method of the corresponding embodiment.

[0238] Core network equipment may include a processor and memory. The memory stores computer programs that can run on the processor. When the processor executes the computer program, it implements… Figure 9 The method of the corresponding embodiment.

[0239] This specification also provides another communication system in its embodiments. This communication system may include a first NTN network device and a second NTN network device.

[0240] The first NTN network device may include a processor and a memory, the memory being used to store computer programs that can run on the processor. When the processor executes the computer program, it implements... Figure 10 The method of the corresponding embodiment.

[0241] The second NTN network device may include a processor and a memory. The memory is used to store computer programs that can run on the processor. When the processor executes the computer program, it implements... Figure 14 The method of the corresponding embodiment.

[0242] In addition, the communication system may include other equipment, such as core network equipment.

[0243] This specification also provides an NTN network device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements... Figure 4 , Figure 10 or Figure 14 The method of the corresponding embodiment.

[0244] This specification also provides a core network device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements... Figure 9 The method of the corresponding embodiment.

[0245] This specification also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described mobility management method.

[0246] This specification also provides a computer program product, which includes a computer program that, when executed by a processor, implements the above-described mobility management method.

[0247] Those skilled in the art will understand that this specification can be provided as a method, system, or computer program product. Therefore, this specification may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware. Furthermore, this specification may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0248] This specification is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments thereof. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. The computer may be a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0249] The functional units in the embodiments of this specification can be integrated into one processing unit, or each functional unit can exist physically separately, or two or more functional units can be integrated into one processing unit.

[0250] Those skilled in the art will understand that the descriptions of the various embodiments in this specification have different focuses, and parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. Furthermore, it is understood that those skilled in the art, after reading this specification, can conceive of any combination of some or all of the embodiments listed in this specification without creative effort, and such combinations are also within the scope of disclosure and protection of this specification.

[0251] Although this specification has been described through embodiments, those skilled in the art will understand that the above embodiments are merely illustrative of the core ideas of this specification. Those skilled in the art will appreciate that many variations and modifications are possible with this specification. It is intended that the appended claims encompass these variations and modifications without departing from the spirit of this specification.

Claims

1. A mobility management method, characterized in that, Applications to NTN network equipment used in non-terrestrial networks include: Determine the transport network layer (TNL) link of the NTN network device; Send indication information to the core network equipment, the indication information being used to indicate the handover configuration of the TNL link.

2. The method according to claim 1, characterized in that, The TNL link includes a first TNL link, which is a newly added TNL link between the NTN network device and the core network device; The indication information is used to indicate the switching type of the first TNL link.

3. The method according to claim 2, characterized in that, The TNL link also includes a second TNL link, which is an existing TNL link between the NTN network device and the core network device; The indication information is used to indicate that the handover type of the first TNL link is a hard handover; The hard handover includes adding the first TNL link and removing the second TNL link on the NG interface between the NTN network device and the core network device.

4. The method according to claim 2, characterized in that, The TNL link also includes a second TNL link, which is an existing TNL link between the NTN network device and the core network device; The indication information is used to indicate that the handover type of the first TNL link is a soft handover; The indication information is also used to indicate the validity period of the second TNL link; The soft handover includes adding the first TNL link on the NG interface between the NTN network device and the core network device, and removing the second TNL link on the NG interface after the effective time expires.

5. The method according to claim 3 or 4, characterized in that, The indication information is carried by the Radio Access Network (RAN) configuration update message.

6. The method according to claim 2, characterized in that, The indication information is used to indicate that the handover type of the first TNL link is a hard handover, and the indication information is also used to indicate the effective time of the first TNL link; The hard handover includes: after the effective time is reached, adding the first TNL link on the NG interface between the NTN network device and the core network device and removing the existing second TNL link between the NTN network device and the core network device.

7. The method according to claim 2, characterized in that, The indication information is used to indicate that the handover type of the first TNL link is a soft handover, and the indication information is also used to indicate the effective time of the first TNL link; The soft handover includes adding the first TNL link on the NG interface between the NTN network device and the core network device after the effective time has elapsed.

8. The method according to claim 2, characterized in that, The indication information is also used to indicate the address of the first TNL link.

9. The method according to any one of claims 2, 6-8, characterized in that, The indication information is carried by the NG establishment request message.

10. A mobility management method, characterized in that, Applied to core network equipment, including: Receive indication information sent from NTN network devices, the indication information being used to indicate the handover configuration of TNL links; Update the availability status of the TNL link according to the indicated information.

11. The method according to claim 10, characterized in that, The TNL link includes a first TNL link, which is a newly added TNL link between the NTN network device and the core network device; The indication information is used to indicate the switching type of the first TNL link.

12. The method according to claim 11, characterized in that, The indication information is used to indicate that the handover type of the first TNL link is a hard handover; updating the availability status of the TNL link according to the indication information includes: The core network device adds the first TNL link and removes the second TNL link on the NG interface between the NTN network device and the core network device; The second TNL link is an existing TNL link between the core network device and the NTN network device.

13. The method according to claim 11, characterized in that, The indication information is used to indicate that the handover type of the first TNL link is a soft handover. The indication information is also used to indicate the validity period of the second TNL link, which is an existing TNL link between the core network device and the NTN network device. Updating the availability status of the TNL link according to the indication information includes: The core network device adds the first TNL link on the NG interface between the NTN network device and the core network device; After the effective time of the second TNL link expires, the core network device removes the second TNL link from the NG interface.

14. The method according to claim 12 or 13, characterized in that, The indication information is carried by the RAN configuration update message.

15. The method according to claim 11, characterized in that, The indication information is used to indicate that the handover type of the first TNL link is a hard handover, and the indication information is also used to indicate the effective time of the first TNL link; Updating the availability status of the TNL link according to the indication information includes: After the effective time is reached, the core network device adds the first TNL link on the NG interface and removes the existing second TNL link between the core network device and the NTN network device.

16. The method according to claim 11, characterized in that, The indication information is used to indicate that the handover type of the first TNL link is a soft handover, and the indication information is also used to indicate the effective time of the first TNL link; Updating the availability status of the TNL link according to the indication information includes: After the effective time is reached, the core network device adds the first TNL link on the NG interface.

17. The method according to claim 11, characterized in that, The indication information is also used to indicate the address of the first TNL link.

18. The method according to any one of claims 11, 15-17, characterized in that, The indication information is carried by the NG establishment request message.

19. The method according to claim 10, characterized in that, The method further includes: Select the target TNL link in the TNL link of the NG interface between the NTN network device and the core network device; Downlink data is sent to the NTN network device using the target TNL link.

20. A mobility management method, characterized in that, Applied to the first NTN network equipment, including: Determine the TNL link of the first NTN network device; Send indication information to the second NTN network device, the indication information being used to indicate the handover configuration of the TNL link.

21. The method according to claim 20, characterized in that, The uplink data transmission direction is from the second NTN network device through the first NTN network device to the core network device; The downlink data transmission direction is from the core network device through the first NTN network device to the second NTN network device.

22. The method according to claim 20, characterized in that, The TNL link includes a first TNL link, which is a newly added TNL link between the first NTN network device and the core network device; The indication information is used to indicate the switching type of the first TNL link.

23. The method according to claim 22, characterized in that, The indication information is also used to indicate at least one of the validity time and address of the first TNL link.

24. The method according to any one of claims 20-23, characterized in that, The indication information is carried by an Xn message, which is either an Xn setup message or a RAN paging message.

25. The method according to claim 20, characterized in that, The method further includes: Send the instruction information to the core network equipment.

26. The method according to claim 25, characterized in that, The indication information is carried by the RAN configuration update message bearer or by the NG establish request message bearer.

27. A mobility management method, characterized in that, Applied to second NTN network devices, including: Receive indication information sent from a first NTN network device, the indication information being used to indicate the handover configuration of the TNL link; The availability status of the TNL link is determined based on the indicated information.

28. The method according to claim 27, characterized in that, The uplink data transmission direction is from the second NTN network device through the first NTN network device to the core network device; The downlink data transmission direction is from the core network device through the first NTN network device to the second NTN network device.

29. The method according to claim 27, characterized in that, The TNL link includes a first TNL link, which is a newly added TNL link between the first NTN network device and the core network device; The indication information is used to indicate the switching type of the first TNL link.

30. The method according to claim 29, characterized in that, The indication information is also used to indicate at least one of the validity time and address of the first TNL link.

31. The method according to any one of claims 27-30, characterized in that, The indication information is carried by an Xn message, which is either an Xn setup message or a RAN paging message.

32. An NTN network device, characterized in that, The NTN network device includes a processor and a memory, the memory being used to store a computer program that can run on the processor, the processor executing the computer program to implement the instructions of any of the methods described in claims 1-9 and 20-31.

33. A core network device, characterized in that, The core network device includes a processor and a memory, the memory being used to store a computer program that can run on the processor, the processor executing the computer program to implement the instructions of any of the methods of claims 10-19.

Images