A method and apparatus for feeder link handover in a communication network

Abstract

Embodiments of the present disclosure provide a method and apparatus for feeder link switching in a communication network. The method (300) performed by a first network node comprises: communicating (S302) with a second network node and a third network node using a first feeder link; performing (S304) a feeder link switching by establishing a second feeder link; transmitting (S306) a second message to the second network node to manage a control plane interface between the first network node and the second network node; and switching (S308) communications between the first network node and the second network node and / or communications between the first network node and the third network node to the second feeder link. The second message comprises transport network layer, TNL, parameters related to the second feeder link. Data transmission interruption or even loss caused by the feeder link switching can be reduced.

Description

Technical Field

[0001] The various exemplary embodiments disclosed herein generally relate to communication technology, and more specifically to a method and apparatus for feeder link switching in a communication network. Background Technology

[0002] In current communication systems, such as 3GPP 5G and New Radio (NR) systems, the communication link used to transmit signaling or data between the transmitter and receiver may change / switch during signaling or data communication for various reasons, while the transmitter and receiver remain unchanged.

[0003] During such a change in communication link, signaling or data transmission may be interrupted or even lost. Therefore, it is desirable to further reduce the impact of such link switching. Summary of the Invention

[0004] This summary is provided to present some aspects in a simplified form, which will be further described in the detailed description below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0005] Certain aspects of this disclosure and its embodiments may provide solutions to these or other challenges. Various embodiments are presented herein to address one or more of the problems disclosed herein. Specific methods and apparatus for feeder link switching in communication networks are also provided.

[0006] A first aspect of this disclosure provides a method for feeder link switching in a communication network, performed by a first network node. The method includes: communicating with a second network node and a third network node using the first feeder link; performing feeder link switching by establishing a second feeder link; transmitting a second message to the second network node to manage the control plane interface between the first and second network nodes; and switching communication between the first and second network nodes and / or between the first and third network nodes to the second feeder link. The second message includes Transport Network Layer (TNL) parameters (or multiple TNL parameters) associated with the second feeder link.

[0007] In an example embodiment of this disclosure, performing a feeder link switch includes transmitting a first message to a second network node to indicate that a feeder link switch from a first feeder link to a second feeder link will be performed by the first network node.

[0008] In an example embodiment of this disclosure, the first message includes TNL parameters associated with the first feeder link. The TNL parameters in the first message include: the TNL address (or multiple TNL addresses) of the first network node before the feeder link switchover; and the TNL parameters in the second message include: the TNL address (or multiple TNL addresses) of the first network node after the feeder link switchover.

[0009] In the example embodiments of this disclosure, at least one of the first message or the second message further includes: an identifier ID of the first network node, and / or a list of at least one identifier of a terminal device connected to the first network node.

[0010] In the example embodiments of this disclosure, the TNL parameter in the second message further includes a mapping between the TNL address (or multiple TNL addresses) of the first network node before the feeder link switch and the TNL address (or multiple TNL addresses) of the first network node after the feeder link switch.

[0011] In the example embodiments of this disclosure, the first message or the second message is a Next Generation NG Establishment Request Message, or a Radio Access Network RAN ​​Configuration Update Message, or an S1 Establishment Request Message, or an eNB Configuration Update Message, or any S1 or NG Application Protocol (AP) message.

[0012] In an example embodiment of this disclosure, the first feeder link includes a first gateway; the second feeder link includes a second gateway; and the first message further includes a time parameter indicating the point in time when the first feeder link becomes unavailable, and / or the point in time when the second feeder link becomes available, and / or the time period during which both the first and second feeder links are available.

[0013] In an example embodiment of this disclosure, a first network node transmits a first message and a second message to a plurality of second network nodes.

[0014] In an example embodiment of this disclosure, the method further includes: after transmitting the second message, receiving control plane messages from a second network node and / or receiving user plane traffic from a third network node via a second feeder link.

[0015] In an example embodiment of this disclosure, the first network node includes a base station; the second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); the third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW); and communication between the first network node and the third network node includes user plane transmission that is suspended before feeder link handover and resumed after feeder link handover.

[0016] In the example embodiments of this disclosure, the communication network is a non-terrestrial network.

[0017] A second aspect of this disclosure provides a method for switching a feeder link in a communication network, performed by a second network node. The method includes: communicating with a first network node using a first feeder link; receiving a second message from the first network node to manage a control plane interface between the first and second network nodes, wherein the second message includes transport network layer (TNL) parameters (or multiple TNL parameters) associated with the second feeder link; initiating a second request to a third network node including the TNL parameters, causing the third network node to switch communication between the first and third network nodes to use the TNL parameters for a list of terminal devices connected to the first network node; and switching communication between the first and second network nodes from the first feeder link to the second feeder link.

[0018] In an example embodiment of this disclosure, communicating with a first network node using a first feeder link includes: receiving a first message from the first network node indicating that a feeder link switch from the first feeder link to a second feeder link will be performed by the first network node; and initiating a first request to a third network node to cause the third network node to suspend communication between the first network node and the third network node for a list of terminal devices connected to the first network node.

[0019] In the example embodiments of this disclosure, at least one of the first message or the first request includes: the TNL address (or multiple TNL addresses) of the first network node before the feeder link switch; and at least one of the TNL parameters (or multiple TNL parameters) in the second message or the TNL parameters in the second request includes: the TNL address (or multiple TNL addresses) of the first network node after the feeder link switch.

[0020] In the example embodiments of this disclosure, at least one of the first message, the second message, the first request, or the second request further includes: an identifier ID of the first network node, and / or a list of identifiers of at least one terminal device connected to the first network node.

[0021] In the example embodiments of this disclosure, at least one of the TNL parameters (or multiple TNL parameters) in the second message or the TNL parameters in the second request further includes: a mapping between the TNL address of the first network node before the feeder link switch and the TNL address (or multiple TNL addresses) of the first network node after the feeder link switch.

[0022] In the example embodiments of this disclosure, the first message or the second message is a Next Generation NG Establishment Request Message, or a Radio Access Network RAN ​​Configuration Update Message, or an S1 Establishment Request Message, or an eNB Configuration Update Message, or an Application Protocol (AP) Message.

[0023] In an example embodiment of this disclosure, the first feeder link includes a first gateway; the second feeder link includes a second gateway; the first message further includes a time parameter indicating the time at which the first feeder link becomes unavailable, and / or the time at which the second feeder link becomes available, and / or the time period during which both the first and second feeder links are available; and the first request includes a time parameter indicating the time at which the third network node suspends communication, and / or the time period during which the third network node suspends communication.

[0024] In an example embodiment of this disclosure, the method further includes: stopping the transmission of control plane messages to the first network node via the first feeder link when a first message is received; and resuming the transmission of control plane messages to the first network node via the second feeder link when a second message is received.

[0025] In an example embodiment of this disclosure, a second network node transmits a first request and a second request to multiple third network nodes.

[0026] In an example embodiment of this disclosure, the first network node includes a base station; the second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); the third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW); and communication includes user plane transmissions that are paused before feeder link handover and resumed after feeder link handover.

[0027] In an example embodiment of this disclosure, initiating a first or second request by the AMF includes: calling a service request, including a list of terminal devices, to the Session Management Function (SMF). The SMF initiates an N4 request to the UPF, the N4 request including a list of identifiers for the list of terminal devices.

[0028] In the example embodiments of this disclosure, the communication network is a non-terrestrial network.

[0029] A third aspect of this disclosure provides a method for feeder link switching in a communication network, performed by a third network node. The method includes: receiving from a second network node a second request including transport network layer (TNL) parameters to cause the third network node to update communications for a list of terminal devices connected to a first network node; updating stored information about the communications using the TNL parameters; and initiating the communications for the list of terminal devices connected to the first network node using the updated information about the communications.

[0030] In an example embodiment of this disclosure, the method further includes: receiving a first request from a second network node to cause a third network node to suspend communication between the first network node and the third network node for a list of terminal devices connected to the first network node; and suspending communication between the first network node and the third network node for a list of terminal devices connected to the first network node.

[0031] In an example embodiment of this disclosure, the first request includes: the TNL address (or multiple TNL addresses) of the first network node before the feeder link switch; and the TNL parameters (or multiple parameters) in the second request include: the TNL address (or multiple TNL addresses) of the first network node after the feeder link switch.

[0032] In the example embodiments of this disclosure, at least one of the first request or the second request further includes: an identifier ID of the first network node, and / or a list of at least one identifier of a terminal device connected to the first network node.

[0033] In an example embodiment of this disclosure, the TNL parameter in the second request further includes a mapping from the TNL address (or multiple TNL addresses) of the first network node before the feeder link switch to the TNL address (or multiple TNL addresses) of the first network node after the feeder link switch.

[0034] In an example embodiment of this disclosure, the first request includes a time parameter indicating the point in time when the third network node suspends communication and / or the duration of the suspension.

[0035] In the example embodiments of this disclosure, the stored information includes at least the user plane transport network layer address of the user plane tunnel for the terminal device connected to the first network node.

[0036] In an example embodiment of this disclosure, the third network node updates at least one IP address of the next-generation user plane NG-U tunnel associated with the first network node based at least on a second request.

[0037] In an example embodiment of this disclosure, the first network node includes a base station; the second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); the communication includes user plane transmissions that are suspended before a feeder link handover and resumed after the feeder link handover; the communication is resumed by using a Transport Network Layer (TNL) connection of the second feeder link; and the third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW).

[0038] In the example embodiments of this disclosure, the first or second request received by the UPF is an N4 request transmitted by the Session Management Function (SMF), and the SMF transmits the N4 request as a response to receiving a service request from the AMF, the service request including a list of identifiers of terminal devices and a list of Protocol Data Units (PDUs) that need to be reactivated.

[0039] In the example embodiments of this disclosure, the communication network is a non-terrestrial network.

[0040] A fourth aspect of this disclosure provides a first network node. The first network node includes components configured to: communicate with a second network node and a third network node using a first feeder link; perform feeder link switching by establishing a second feeder link; transmit a second message to the second network node to manage the control plane interface between the first and second network nodes; and switch communication between the first and second network nodes and / or between the first and third network nodes to the second feeder link. The second message includes Transport Network Layer (TNL) parameters (or multiple TNL parameters) associated with the second feeder link. The components include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first network node to perform the aforementioned operations.

[0041] In exemplary embodiments of this disclosure, the component is also configured to perform a method according to any exemplary embodiment of the first aspect.

[0042] A fifth aspect of this disclosure provides a second network node. The second network node includes components configured to: communicate with a first network node using a first feeder link; receive a second message from the first network node to manage a control plane interface between the first and second network nodes, wherein the second message includes transport network layer (TNL) parameters (or multiple TNL parameters) associated with the second feeder link; initiate a second request to a third network node including the TNL parameters, causing the third network node to switch communication between the first and third network nodes to use the TNL parameters for a list of terminal devices connected to the first network node; and switch communication between the first and second network nodes from the first feeder link to the second feeder link. The components include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second network node to perform the above operations.

[0043] In exemplary embodiments of this disclosure, the component is also configured to perform a method according to any exemplary embodiment of the second aspect.

[0044] A sixth aspect of this disclosure provides a third network node. The third network node includes components configured to: receive from a second network node a second request including transport network layer (TNL) parameters associated with a second feeder link, causing the third network node to update communications for a list of terminal devices connected to a first network node; update stored information about the communications using the TNL parameters; and initiate the communications for the list of terminal devices connected to the first network node using the updated information about the communications. The components include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the third network node to perform the aforementioned operations.

[0045] In exemplary embodiments of this disclosure, the component is also configured to perform a method according to any exemplary embodiment of the third aspect.

[0046] A seventh aspect of this disclosure provides a computer-readable storage medium. The computer-readable storage medium stores instructions that, when executed by at least one processor of a network node, cause at least one processor of the network node to perform a method according to any example embodiment of the first, second, and third aspects.

[0047] According to embodiments of this disclosure, exemplary embodiments propose a mechanism that enables faster and more accurate pausing / resumption of communication in a communication network during feeder link switching. Data transmission interruptions or even losses caused by feeder link switching can be reduced. Attached Figure Description

[0048] The above and other aspects, features, and benefits of various embodiments of this disclosure will become more apparent by way of example, in conjunction with the following detailed description with reference to the accompanying drawings, in which the same reference numerals or letters are used to denote the same or equivalent elements. The drawings are illustrated to facilitate a better understanding of embodiments of this disclosure and are not necessarily drawn to scale, wherein: Figure 1 This is a diagram illustrating an example architecture for a regenerated NTN deployment.

[0049] Figure 2 This is a diagram illustrating an example of feeder link switching (FLSO).

[0050] Figure 3A This is a flowchart illustrating a method performed by a first network node according to an example embodiment of the present disclosure.

[0051] Figure 3B Examples of embodiments according to this disclosure are shown as follows. Figure 3A A flowchart of the further steps of the method shown.

[0052] Figure 3CExamples of embodiments according to this disclosure are shown as follows. Figure 3A A flowchart of the further steps of the method shown.

[0053] Figure 4A This is a flowchart illustrating a method performed by a second network node according to an example embodiment of the present disclosure.

[0054] Figure 4B Examples of embodiments according to this disclosure are shown as follows. Figure 4A A flowchart of the further steps of the method shown.

[0055] Figure 4C Examples of embodiments according to this disclosure are shown as follows. Figure 4A A flowchart of the further steps of the method shown.

[0056] Figure 4D Examples of embodiments according to this disclosure are shown as follows. Figure 4A A flowchart of the further steps of the method shown.

[0057] Figure 5A This is a flowchart illustrating a method performed by a third network node according to an example embodiment of the present disclosure.

[0058] Figure 5B Examples of embodiments according to this disclosure are shown as follows. Figure 5A A flowchart of the further steps of the method shown.

[0059] Figure 6 This is a diagram illustrating an example call flow according to an embodiment of the present disclosure.

[0060] Figure 7 This is a block diagram illustrating an example structure of a first network node according to an example embodiment of the present disclosure.

[0061] Figure 8 This is a block diagram illustrating an example structure of a second network node according to an example embodiment of the present disclosure.

[0062] Figure 9 This is a block diagram illustrating an example structure of a third network node according to an example embodiment of the present disclosure.

[0063] Figure 10 This is a block diagram illustrating an apparatus / computer-readable storage medium according to embodiments of the present disclosure.

[0064] Figure 11 This is a block diagram illustrating an example apparatus unit suitable for performing a method according to an embodiment of the present disclosure for a first network node.

[0065] Figure 12This is a block diagram illustrating an example device unit suitable for performing a method according to an embodiment of the present disclosure for a second network node.

[0066] Figure 13 This is a block diagram illustrating an example device unit suitable for performing a method according to an embodiment of the present disclosure in a third network node. Detailed Implementation

[0067] Embodiments of this disclosure have been described in detail with reference to the accompanying drawings. It should be understood that these embodiments are discussed for better understanding only and are not intended to limit the scope of this disclosure. The features, advantages, and characteristics of this disclosure described may be combined in any suitable manner in one or more embodiments.

[0068] Generally, all terms used herein will be interpreted according to their common meaning in the relevant art, unless a different meaning is clearly given and / or implied from the context in which it is used. Unless the context explicitly gives and / or implies, the steps of any method disclosed herein need not be performed in the exact order disclosed. Where appropriate, any feature of any embodiment disclosed herein may be applied to any other embodiment.

[0069] As used herein, the term "network" or "communication network" refers to a network that conforms to any suitable communication standard (such as the Internet or any wireless network). For example, wireless communication standards may include WLAN (Wireless Local Area Network), New Radio (NR), Long Term Evolution (LTE), LTE-Advanced, 5G NR, etc. In the following description, the terms "network" and "system" are used interchangeably.

[0070] The term "node / network node" refers to a computing device, computing entity, computing function, or any other device (physical or virtual) in a communication network. For example, a node in a network can include a base station (BS), an access point (AP), or any other suitable device in a wireless communication network. A BS can be, for example, a Node B (or NB), an evolved Node B (eNodeB or eNB), a next-generation Node B (gNodeB or gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, or a low-power node such as a femtocell or picocell. Furthermore, a node can include other core network nodes, such as Access and Mobility Management Functions (AMF), Session Management Functions (SMF), User Plane Functions (UPF), Mobility Management Entities (MME), or Serving Gateways (S-GW).

[0071] The term "terminal device" refers to any terminal device capable of accessing a communication network and receiving services therefrom. By way of example and not limitation, a terminal device refers to a mobile terminal, user equipment (UE), non-AP device (such as a non-AP site (STA)), or other suitable device. Terminal devices may include, but are not limited to, mobile phones, cellular phones, smartphones, wearable devices, in-vehicle wireless terminal equipment, vehicles, etc.

[0072] As an example, a terminal device can refer to a device configured to communicate according to one or more communication standards promulgated by any standards organization, such as the 3rd Generation Partnership Project (3GPP).

[0073] As another example, in the Internet of Things (IoT) scenario, a terminal device can represent a machine or other device that performs monitoring and / or measurement and transmits the results of such monitoring and / or measurement to another terminal device and / or network device. Specific examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or household or personal appliances such as refrigerators, televisions, and personal wearable devices such as watches. In other scenarios, a terminal device can represent a vehicle or other device capable of monitoring and / or reporting its operating status or other functions associated with its operation.

[0074] It should be understood that although the terms “first” and “second”, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed terms.

[0075] As used herein, “at least one of the following: a list of two or more elements” and “at least one of the following: a list of two or more elements” and similar wording (where the list of two or more elements is connected by “and” or “or”) means at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0076] The exemplary embodiments of this disclosure relate to methods and apparatus for feeder link switching in communication networks.

[0077] For illustrative purposes, some embodiments relate to hard feeder link switching (FLSO) or soft feeder link switching (FLSO) in a non-terrestrial network (NTN) regenerative architecture with a gNB on a satellite. In this scenario, the gNB and the satellite are interchangeable. However, it should be noted that the embodiments of this disclosure can also be applied to other scenarios where communication links change / switch. It should also be noted that the gNB is merely an example. The base station can also be an eNB, ng-eNB, or any other type of base station.

[0078] Figure 1 This is a diagram illustrating an example architecture for a regenerated NTN deployment.

[0079] like Figure 1 As shown, the UE can connect to the data network via the gNB and the 5G CN (fifth-generation core network). NR Uu can be the interface between the UE and the gNB. The gNB is connected to the 5GCN via a feeder link between a satellite and a gateway (e.g., NTN gateway 1). The NG interface between the gNB and the 5G CN is transmitted via NG over SRI (Satellite Radio Interface). N6 is the interface between the 5G CN and the data network.

[0080] An NTN gateway (GW), gateway, or NTN-GW is a transport network node. When a satellite / gNB connects to an NTN-GW, the gNB is assigned one or more Transport Network Layer (TNL) addresses anchored within the NTN-GW, such as one or more IP addresses. This ensures that downlink (DL) control plane / user plane (CP / UP) traffic with the destination Internet Protocol (IP) address set to the gNB's IP address is routed to the correct NTN-GW and then further forwarded to the satellite / gNB. Different IP addresses can be assigned to the gNB for the control plane and user plane. In other words, a gNB can have more than one IP address.

[0081] During NTN operation, it may be necessary to switch feeder links between different NTN GWs serving the same satellite (such as switching from NTN Gateway 1 to NTN Gateway 2). This could be due to, for example, maintenance, traffic offloading, or (for Low Earth Orbit (LEO)) because the satellite moves out of the current NTN GW's visibility range. After FLSO, the gNB is assigned one or more new IP addresses anchored in the new NTN-GW.

[0082] In hard feeder link switching (hard FLSO), an NTN payload (e.g., a satellite) is connected to only one NTN gateway at any given time; that is, radio link interruptions can occur during transitions between feeder links. In soft feeder link switching (soft FLSO), an NTN payload (e.g., a satellite) can be connected to two NTN gateways for a period of time.

[0083] FLSO can operate without altering the base station (e.g., gNB) and / or core network (e.g., Access and Mobility Management Function (AMF)), thus the UE can still be served by the same base station and core network (e.g., gNB and AMF). The satellite can be either geostationary or geomobile.

[0084] Figure 2 This is a diagram showing an example of FLSO.

[0085] ● At T1, before FLSO, satellite 1 / gNB1 connects to NTN-GW1 and further connects to AMF. The satellite is far from NTN-GW1, therefore a change to the closer NTN-GW2 is necessary.

[0086] ● At T1+0.5(s), after FLSO, satellite 1 / gNB1 will change the feeder link to use NTN-GW2. The UE is still served by the same gNB and the same AMF.

[0087] It should be noted that feeder link handover can be performed cell-by-cell. For example, for a satellite with 16 beams, cells can be switched one feeder link to another one by one. For a single cell, this is still considered a hard handover; however, for a satellite, both feeder links are available during the handover.

[0088] In the current Next Generation (NG) interface, the Transport Network Layer (TNL) connection may be temporarily lost, for example, due to IP network problems. After the TNL connection is restored, the gNB initiates the NG establishment process. The NG SETUP REQUEST message includes a value set to "user-retained". UE Retention Information (UE reserved information) IE. 3GPP Technical Specification (TS) 38.413 V17.6.0 (2023-09) specifies the following behavior: If the NG SETUP REQUEST message includes a UE Retention that is set to "ues-retained"... Information IE, then AMF can include the message set to be in the NG SETUP RESPONSE message. The "ues-retained" UE Retention Information IE is used to retain existing UE-related context and signaling connections. The proposal was accepted.

[0089] By using UE Retention Information IE, gNB, and AMF can all preserve the existing UE context and do not affect the UE during short TNL connection loss and recovery.

[0090] In the NTN transparent architecture, hard FLSO can also be performed without the aforementioned problems. In the transparent architecture, the gNB is located on the ground. Therefore, the gNB can buffer DL packets during hard FLSO.

[0091] - In the case of a new satellite serving a UE, the gNB will forward buffered DL packets to the new satellite.

[0092] - While existing satellites are still serving the UE, the gNB forwards buffered DL packets to existing satellites via the new NTN-GW.

[0093] Therefore, this issue does not apply to NTN transparent architectures. However, this solution is not applicable when the satellite carries a gNB.

[0094] 3GPP TS 23.401 V18.4.0 (2023-12) / 3GPP TS 23.501 V18.4.0 (2023-12) and TS 29.502 V18.4.0 (2023-09) specify some pause procedures.

[0095] During this recovery process, During the connection suspension process, the UPF was instructed to remove the DL N3 tunnel of the access network (AN). The UPF retains UL N3 tunnel information, while the UPF retains UL N3 tunnel information (i.e., the UPF accepts and forwards UL data). "After that, a service request triggered by the UE (or a service request triggered by the network) is executed to provide the UPF with the AN's DL N3 tunnel information."

[0096] In such a process, the service request process includes many procedures to be performed.

[0097] In the embodiments of this disclosure, the UPF still retains the DL N3 tunnel information of the AN for each UE, but only stops DL transmission. After FLSO, the UPF updates the stored DL N3 tunnel information to use the new TNL address of the gNB.

[0098] In embodiments of this disclosure, a single process is performed to update the UPF with the new DL N3 TNL address information of the AN (e.g., the DL tunnel endpoint identifier (TEID) assigned by the gNB remains unchanged, but only the IP address of the gNB changes).

[0099] Specifically, in the NTN regenerative architecture, FLSO changes the NTN-GW. gNB / AMF can remain unchanged, but it can also be changed.

[0100] The following examples discuss FLSO scenarios where gNB / AMF remains unchanged.

[0101] ●Step 1: gNB1 connects to NTN-GW1. gNB1 is assigned IP address #1 anchored in NTN-GW1.

[0102] ●Step 2: gNB1 establishes a TNL connection and NG interface with AMF1.

[0103] ●Step 3: The UE connects to gNB1.

[0104] ●Step 4: When the AMF / UPF sends a DL NG control plane / user plane (NG-C / U) IP packet to gNB1, it uses IP address #1 as the destination IP address of the DL NG-C / U IP packet. Therefore, the DL NG-C / U IP packet is routed to NTN-GW1 and further transmitted to gNB1.

[0105] ●Step 5: gNB1 performs a hard FLSO, i.e., disconnects from NTN-GW1 and connects to NTN-GW2. gNB1 is assigned a new IP address #2 anchored in NTN-GW2.

[0106] ●Step 6: gNB1 establishes a TNL connection with AMF1.

[0107] ●Step 7: gNB1 sends an NG SETUP REQUEST message, which includes the value set to "user-retained". UE Retention Information Both IE, gNB1, and AMF1 retain the existing UE context.

[0108] ●Step 8: gNB1 uses the new IP address #2 as the destination IP address for the DL NG-C IP packets; the DL NG-C IP packets are routed via NTN-GW2 and further transmitted to gNB1. There are no issues with NG-C.

[0109] However, the UPF was unaware of both the FLSO and the change in gNB1's IP address. The UPF continued sending DL NG-U traffic using the old IP address #1, which was routed to NTN-GW1. Since gNB1 was no longer connected to NTN-GW1, NTN-GW1 was unable to send DL data to gNB1. This resulted in packet loss and service interruption for existing UEs.

[0110] This disclosure can provide some example embodiments for reducing such packet loss and service interruption.

[0111] Figure 3A This is a flowchart illustrating a method performed by a first network node according to an example embodiment of the present disclosure.

[0112] like Figure 3AAs shown, method 300 includes: step S302, communicating with a second network node and a third network node using a first feeder link; step S304, performing feeder link switching by establishing a second feeder link; step S306, transmitting a second message to the second network node to manage the control plane interface between the first network node and the second network node; and step S308, switching the communication between the first network node and the second network node and / or the communication between the first network node and the third network node to the second feeder link. The second message includes Transport Network Layer (TNL) parameters associated with the second feeder link.

[0113] According to embodiments of this disclosure, when the first network performs a feeder link switch, it can notify the second and third network nodes. Therefore, unexpected interruptions or data loss can be reduced.

[0114] Figure 3B Examples of embodiments according to this disclosure are shown as follows. Figure 3A A flowchart of the further steps of the method shown.

[0115] In an example embodiment of this disclosure, step S304 of performing feeder link switching includes: step S3042, transmitting a first message to a second network node to indicate that the feeder link switching from the first feeder link to the second feeder link will be performed by the first network node.

[0116] According to embodiments of this disclosure, feeder link switching can be implicitly indicated, such as through a second message, or explicitly indicated, such as through a first message.

[0117] In an example embodiment of this disclosure, the first message includes TNL parameters associated with the first feeder link. The TNL parameters in the first message include the TNL address (e.g., Internet Protocol IP address) of the first network node before the feeder link switch; and the TNL parameters in the second message include the TNL address (e.g., IP address) of the first network node after the feeder link switch.

[0118] In the example embodiments of this disclosure, at least one of the first message or the second message further includes: an identifier ID of the first network node, and / or a list of at least one identifier of a terminal device connected to the first network node.

[0119] In an example embodiment of this disclosure, the TNL parameter in the second message further includes a mapping between the TNL address (e.g., IP address) of the first network node before the feeder link switch and the TNL address (e.g., IP address) of the first network node after the feeder link switch.

[0120] According to embodiments of this disclosure, the first feeder link and / or the second feeder link may be indicated by different parameters, such as TNL addresses (e.g., IP addresses) or identifiers.

[0121] In the example embodiments of this disclosure, the first message or the second message is a Next Generation NG Establishment Request Message, a Radio Access Network RAN ​​Configuration Update Message, an S1 Establishment Request Message, an eNB Configuration Update Message, or any Application Protocol (AP) message.

[0122] According to embodiments of this disclosure, different types of second messages can be used for different scenarios. For example, when a control plane interface needs to be established, the second message can be an NG establishment request message or an S1 establishment request message. When a control plane interface needs to be updated, a RAN configuration update message or an eNB configuration update message can be used.

[0123] In an example embodiment of this disclosure, the first feeder link includes a first gateway; the second feeder link includes a second gateway; and the first message further includes a time parameter indicating the time point at which the first network node disconnects from the first gateway or the time point at which the first feeder link becomes unavailable, and / or the time point at which the second feeder link becomes available, and / or the time period during which both the first and second feeder links are available.

[0124] According to embodiments of this disclosure, by utilizing time parameters, the pause and resumption of communication during feeder link switching can be precisely controlled. This can reduce communication interruptions.

[0125] In an example embodiment of this disclosure, a first network node transmits a first message and a second message to a plurality of second network nodes.

[0126] According to embodiments of this disclosure, even when multiple second network nodes are involved, related communications can be suspended.

[0127] Figure 3C Examples of embodiments according to this disclosure are shown as follows. Figure 3A A flowchart of the further steps of the method shown.

[0128] like Figure 3C As shown, method 300 further includes: step S310, after transmitting the second message, receiving control plane messages from the second network node and / or receiving user plane traffic from the third network node via the second feeder link.

[0129] In an example embodiment of this disclosure, the first network node includes a base station; the second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); the third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW); and communication between the first network node and the third network node includes user plane transmissions that are suspended before feeder link handover and resumed after feeder link handover.

[0130] According to embodiments of this disclosure, user plane transmission interruptions or losses between base stations and core networks (such as UPF or S-GW) can be reduced.

[0131] In the example embodiments of this disclosure, the communication network is a non-terrestrial network.

[0132] According to embodiments of this disclosure, as a specific example, the proposed technical solution can be applied to non-terrestrial networks. However, it should be noted that the proposed technical solution can also be applied to other types of networks.

[0133] Figure 4A This is a flowchart illustrating a method performed by a second network node according to an example embodiment of the present disclosure.

[0134] like Figure 4A As shown, method 400 includes: step S402, communicating with a first network node using a first feeder link; step S404, receiving a second message from the first network node to manage the control plane interface between the first network node and a second network node, wherein the second message includes transport network layer (TNL) parameters related to the second feeder link; step S406, initiating a second request to a third network node including the TNL parameters, so that the third network node switches the communication between the first network node and the third network node to use the TNL parameters for a list of terminal devices connected to the first network node; and step S408, switching the communication between the first network node and the second network node from the first feeder link to the second feeder link.

[0135] Figure 4B Examples of embodiments according to this disclosure are shown as follows. Figure 4A A flowchart of the further steps of the method shown.

[0136] like Figure 4B As shown, step S402 of communicating with the first network node using the first feeder link includes: step S4022, receiving a first message from the first network node to indicate that the feeder link switch from the first feeder link to the second feeder link will be performed by the first network node; and step S4024, initiating a first request to the third network node to cause the third network node to suspend communication between the first network node and the third network node for a list of terminal devices connected to the first network node.

[0137] In an example embodiment of this disclosure, at least one of the first message or the first request includes: the TNL address (e.g., IP address) of the first network node before the feeder link switch; and at least one of the TNL parameters in the second message or the TNL parameters in the second request includes: the TNL address (e.g., IP address) of the first network node after the feeder link switch.

[0138] In the example embodiments of this disclosure, at least one of the first message, the second message, the first request, or the second request further includes: an identifier ID of the first network node, and / or a list of identifiers of at least one terminal device connected to the first network node.

[0139] In the example embodiments of this disclosure, at least one of the TNL parameters in the second message or the TNL parameters in the second request further includes: a mapping between the TNL address (e.g., IP address) of the first network node before the feeder link switch and the TNL address (e.g., IP address) of the first network node after the feeder link switch.

[0140] In the example embodiments of this disclosure, the first message or the second message is a Next Generation NG Establishment Request Message, a Radio Access Network RAN ​​Configuration Update Message, an S1 Establishment Request Message, an eNB Configuration Update Message, or an Application Protocol (AP) Message (e.g., any S1 or NG AP Message).

[0141] In an example embodiment of this disclosure, the first feeder link includes a first gateway; the second feeder link includes a second gateway; the first message further includes a time parameter indicating the time at which the first feeder link becomes unavailable, and / or the time at which the second feeder link becomes available, and / or the time period during which both the first and second feeder links are available; and the first request includes a time parameter indicating the time at which the third network node suspends communication, and / or the time period during which the third network node suspends communication.

[0142] Figure 4C Examples of embodiments according to this disclosure are shown as follows. Figure 4A A flowchart of the further steps of the method shown.

[0143] like Figure 4C As shown, method 400 further includes: step S412, stopping the transmission of control plane messages to the first network node via the first feeder link (or via the first gateway) when the first message is received; and step S414, resuming the transmission of control plane messages to the first network node via the second feeder link (or via the second gateway) when the second message is received.

[0144] In an example embodiment of this disclosure, a second network node initiates a first request and a second request to multiple third network nodes.

[0145] In an example embodiment of this disclosure, the first network node includes a base station; the second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); the third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW); and communication includes user plane transmissions that are paused before feeder link handover and resumed after feeder link handover.

[0146] Figure 4D Examples of embodiments according to this disclosure are shown as follows. Figure 4A A flowchart of the further steps of the method shown.

[0147] In an example embodiment of this disclosure, initiating a first or second request by the AMF includes step S416: calling a service request, including a list of terminal device identifiers, to the Session Management Function (SMF). The SMF then initiates an N4 request to the UPF, the N4 request including the list of identifiers for the terminal devices. The service request and the N4 request may also include at least one TNL parameter, such as the TNL address of the first network node before the feeder link switch, and / or the TNL address of the first network node after the feeder link switch, and / or a mapping from the TNL address of the first network node before the feeder link switch to the TNL address of the first network node after the feeder link switch.

[0148] For example, the SMF can receive a pause from the AMF and then send an N4 pause to the UPF. The SMF can also receive an update from the AMF and then send an N4 update to the UPF.

[0149] In the example embodiments of this disclosure, the communication network is a non-terrestrial network.

[0150] Figure 5A This is a flowchart illustrating a method performed by a third network node according to an example embodiment of the present disclosure.

[0151] like Figure 5A As shown, method 500 includes: step S506, receiving a second request from a second network node including transport network layer parameters related to a second feeder link, so that a third network node updates communication for a list of terminal devices connected to a first network node; step S508, updating stored information about the communication using the transport network layer parameters; and step S510, initiating communication for the list of terminal devices connected to the first network node using the updated information about the communication.

[0152] Figure 5B Examples of embodiments according to this disclosure are shown as follows. Figure 5AA flowchart of the further steps of the method shown.

[0153] like Figure 5B As shown, method 500 further includes: step S502, receiving a first request from a second network node to cause a third network node to suspend communication between the first network node and the third network node for a list of terminal devices connected to the first network node; and step S504, suspending communication between the first network node and the third network node for a list of terminal devices connected to the first network node.

[0154] According to embodiments of this disclosure, a third network node can suspend communication in response to a message from a second node, and then resume communication. Therefore, communication interruptions or even communication loss can be reduced.

[0155] In an example embodiment of this disclosure, the first request includes: the TNL address (e.g., IP address) of the first network node prior to the feeder link switch; and the TNL parameter in the second request includes: the TNL address (e.g., IP address) of the first network node after the feeder link switch.

[0156] In the example embodiments of this disclosure, at least one of the first request or the second request further includes: an identifier ID of the first network node, and / or at least one identifier of the terminal device connected to the first network node.

[0157] In an example embodiment of this disclosure, the TNL parameter in the second request further includes a mapping from the TNL address (e.g., IP address) of the first network node before the feeder link switch to the TNL address (e.g., IP address) of the first network node after the feeder link switch.

[0158] In an example embodiment of this disclosure, the first request includes a time parameter indicating the point in time when the third network node suspends communication and / or the duration of the suspension.

[0159] In the exemplary embodiments of this disclosure, the stored information includes at least the user plane transport network layer address for one or more user plane tunnels of one or more terminal devices connected to the first network node. For example, the stored information may include a downlink fully qualified tunnel endpoint identifier (F-TEID) for one or more terminal devices connected to the first network node.

[0160] In an example embodiment of this disclosure, the third network node updates at least one TNL address (e.g., an IP address) for a next-generation user plane (NG-U) tunnel associated with the first network node, based at least on a second request. In another example embodiment, the third network node updates at least one TNL address (e.g., an IP address) for a user plane tunnel (e.g., an S1-U tunnel) associated with the first network node, based at least on a second request.

[0161] In an example embodiment of this disclosure, the first network node includes a base station; the second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); the communication includes user plane transmissions that are suspended before a feeder link handover and resumed after the feeder link handover; the communication is resumed via a Transport Network Layer (TNL) connection in the second feeder link; and the third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW).

[0162] In the example embodiments of this disclosure, the first or second request received by the UPF is an N4 request transmitted by the Session Management Function (SMF). The SMF transmits the N4 request as a response to a service request received from the AMF, which includes a list of terminal device identifiers (e.g., a list of PDUs that need to be reactivated). The N4 request and the service request may also include TNL parameters, such as the TNL address of the first network node before the feeder link switch, and / or the TNL address of the first network node after the feeder link switch, and / or a mapping from the TNL address of the first network node before the feeder link switch to the TNL address of the first network node after the feeder link switch.

[0163] In the example embodiments of this disclosure, the communication network is a non-terrestrial network.

[0164] Figure 6 This is a diagram illustrating an example call flow according to an embodiment of the present disclosure.

[0165] Embodiments of this disclosure provide components for minimizing packet loss and service interruption during hard FLSO in an NTN system.

[0166] More specifically, network nodes can perform the following actions.

[0167] gNB1 can perform the following actions.

[0168] ● When a hard FLSO is detected, gNB1 sends a notification to AMF1 regarding the upcoming hard FLSO. Figure 6 Step 1) ●After gNB1 connects to the new NTN-GW2 and is assigned (multiple) new IP addresses, gNB1 initiates an NG procedure, such as an NG setup procedure, requesting the UPF to use (multiple) new IP addresses for DL ​​NG-U. Figure 6 Step 5) ● Uplink / downlink NG-C / U is restored using (multiple) new IP addresses anchored in the new NTN-GW. NG-C / U traffic is transmitted via new feeder links associated with (multiple) new IP addresses.

[0169] AMF can perform the following actions.

[0170] ● Upon receiving notification of an impending hard FLSO from the gNB, the AMF requests the UPF (via the SMF) to suspend all DL transmissions to gNB1 or (multiple) specific IP addresses. Figure 6 Steps 1, 2 and 3 in the process) - AMF also stopped DL NG-C transmission to gNB1 via the existing (or first) feeder link associated with IP address #1.

[0171] ● Upon receiving an NG SETUP REQUEST including (multiple) new IP addresses, the AMF sends an update to the UPF (via the SMF) to update (multiple) IP addresses of the NG-U tunnel associated with gNB1, or with existing IP addresses of gNB1, or with a list of end devices connected to gNB1. Figure 6 Steps 5, 6 and 7 in the process) ●AMF resumes DL NG-C transmission to gNB1 using the new IP addresses. NG-C traffic is transmitted via a new feeder link associated with (multiple) new IP addresses.

[0172] UPF can perform the following actions.

[0173] ● Upon receiving a pause request, the UPF suspends DL transmissions for all NG-U tunnels associated with gNB1, gNB1(multiple) specific IP addresses, or a list of terminal devices connected to gNB1, but retains the DL fully qualified tunnel endpoint identifier (F-TEID) for the relevant UE / PDU session. Figure 6 Steps 2 and 3 in the process) ● Upon receiving an update request, the UPF updates all relevant NG-U tunnels to use the new IP address(s), and resumes DL transmissions to the new IP address(s) for all relevant NG-U tunnels, targeting the list of end devices. Figure 6 In steps 6 and 7), NG-U traffic is transmitted via a new feeder link associated with (multiple) new IP addresses.

[0174] Furthermore, the steps of the call flow in Figure 3 will be explained in detail below.

[0175] Step 0: gNB1 connects to AMF1 via NTN-GW1. gNB1 is assigned (e.g., IP address #1) anchored in NTN-GW1. DL / UL NG-C / U uses IP address #1 and is routed via NTN-GW1.

[0176] ●Step 1: gNB1 decides to perform a hard FLSO. gNB1 sends a notification of the upcoming hard FLSO to AMF1. The purpose is to request AMF / UPF to stop using existing (multiple) IP addresses (e.g., IP address #1) (i.e., using the first feeder link) for DLNG-C / U transmission.

[0177] This notification can indicate a specific time when the first feeder link becomes unavailable or gNB1 will disconnect from NTN-GW1, such as the start of the disconnection process, a specific time when the second feeder link becomes available, or a period of time when both the first and second feeder link network nodes are available. AMF1 can use this time to determine when it needs to stop DLNG-C and perform step 2 to stop DL NG-U. Therefore, communication can be suspended at or just before this time / period.

[0178] AMF stops transmitting to DL NG-C on gNB1.

[0179] When gNB1 is connected to multiple AMFs, repeat step 1 for each connected AMF.

[0180] ●Steps 2 and 3: AMF1 initiates a pause request to UPF via SMF to pause DL transmissions for the UE list or all UEs served by gNB1. The request may include the IP address of gNB1 (e.g., #1), the ID of gNB, or a list of IDs of at least one UE connected to gNB1 and served by the UPF.

[0181] Upon receiving a pause request, the UPF halts DL NG-U transmissions for all relevant NG-U tunnels, which can be identified using the IP address of gNB1 (e.g., #1), the gNB's ID, or a list of UE IDs, and retains the DL F-TEID information for those UEs connected to the satellite / gNB1. It should be noted that this differs from the connection pause procedure described above, which releases the DL F-TEID information in the UPF. In embodiments of this disclosure, the UPF still retains the DL F-TEID for all UEs connected to the satellite / gNB1. During a hard FLSO, only the gNB's IP address changes, while the TEID assigned by the gNB can remain unchanged (because the same gNB exists before and after the FLSO).

[0182] Furthermore, the IP address change in DL F-TEID applies to the UE list or all UEs connected to the satellite / gNB. Therefore, using non-UE-associated signaling may be better (e.g., simply indicating the satellite / gNB in ​​the signaling may be sufficient), as many UEs may be connected to gNB1. Using non-UE-associated signaling avoids signaling storms for the SMF / UPF. The required changes apply to both the AMF-SMF and SMF-UPF interfaces.

[0183] - There may be multiple UPFs for a UE connected to satellite / gNB1. Repeat steps 2 / 3 for all relevant SMFs / UPFs serving (multiple) UEs connected to satellite / gNB1.

[0184] Alternatively or additionally, AMF1 may also send specific time information to SMF / UPF so that UPF can stop DL transmission at a specific time (or just before) when satellite / gNB1 disconnects from NTN-GW1.

[0185] ●Step 4: gNB1 performs a hard FLSO, i.e., disconnects from NTN-GW1 and connects to NTN-GW2. gNB1 is assigned (multiple) new IP addresses (e.g., IP address #2) anchored in NTN-GW2. The first feeder link is disconnected and a second feeder link is established.

[0186] ●Step 5: gNB1 establishes a TNL connection with AMF via NTN-GW2 using the new IP address. gNB1 sends an NG SETUP REQUEST message to AMF1. This message includes: - Set to "user-retained" UE Retention Information IE; - gNB1 uses (multiple) new IP addresses for NG-U. In cases where gNB1 uses multiple IP addresses for NG-U, this information can be a mapping from gNB1's old IP address (anchored in NTN-GW1) to gNB1's new IP address (anchored in NTN-GW2).

[0187] Upon receiving the NG SETUP REQUEST message, AMF1 accepts the proposal to retain the existing UE-related context and learns the (multiple) NG-U IP addresses that need to be updated. AMF1 also resumes DL NG-C transmission to gNB1 via NTN-GW2. In other words, NG-C communication between AMF1 and gNB1 switches from the first feeder link using NTN-GW1 to the second feeder link using NTN-GW2.

[0188] ●Steps 6 and 7: The AMF initiates an update process via the SMF to request the UPF to update the IP addresses (multiple) of the NG-U tunnel associated with gNB1. The request message includes a mapping from the old IP address of gNB1 (associated with the first feeder link and anchored in NTN-GW1) to the new IP address of gNB1 (associated with the second feeder link and anchored in NTN-GW2).

[0189] - Alternatively or additionally, the request may include the gNB ID of gNB1, which indicates that updates apply to all NG-U tunnels for that gNB.

[0190] UPF updates all NG-U tunnels associated with or connected to gNB1 to use multiple new IP addresses anchored in NTN-GW2. UPF then resumes DL transport for all associated NG-U tunnels via NTN-GW2 using these new IP addresses. NG-U traffic switches from using multiple old IP addresses anchored in NTN-GW1 to using multiple new IP addresses anchored in NTN-GW2.

[0191] Upon completion of step 5, the uplink / downlink NG-C / U (AMF1, UPF) between gNB1 and 5GC is routed via NTN-GW2. In other words, communication between gNB1 and AMF1, and communication between gNB1 and UPF1, is switched from the first feeder link to the second feeder link.

[0192] The embodiments of this disclosure provide the following benefits: avoiding DL NG-U packet loss during hard FLSO and providing a fast method for suspending / resuming DL NG-U for all UEs served by the gNB / satellite. It should be understood that steps 5, 6, and 7 can also be performed in the case of soft FLSO, thereby enabling the user plane tunnel of the list of terminal devices connected to the same gNB / satellite to be updated, in a single procedure, from the old IP addresses associated with the old NTN-GW and the first feeder link before the feeder link handover to the new IP addresses associated with the new NTN-GW and the second feeder link after the feeder link handover.

[0193] This implementation is particularly applicable to improving standardization in relevant 3GPP specifications such as TS23.501 V18.4.0 (2023-12), TS23.502 V18.4.0 (2023-12), TS38.413 V17.6.0 (2023-09), etc.

[0194] Figure 7 This is a block diagram illustrating an example structure of a first network node according to an example embodiment of the present disclosure.

[0195] like Figure 7 As shown, the first network node 70 includes a component 700 configured to: communicate with a second network node and a third network node using a first feeder link; perform feeder link switching by establishing a second feeder link; transmit a second message to the second network node to manage the control plane interface between the first and second network nodes; and switch communication between the first and second network nodes and / or between the first and third network nodes to the second feeder link. The second message includes Transport Network Layer (TNL) parameters associated with the second feeder link.

[0196] In an example embodiment of this disclosure, component 700 includes: at least one processor 702; and at least one memory 704 storing instructions that, when executed by at least one processor 702, cause the first network node 70 to perform the operations described above.

[0197] In exemplary embodiments of this disclosure, component 700 is also configured to perform methods according to any of the foregoing embodiments, such as Figure 3A , Figure 3B , Figure 3C and Figure 6 The method shown.

[0198] Figure 8 This is a block diagram illustrating an example structure of a second network node according to an example embodiment of the present disclosure.

[0199] like Figure 8As shown, the second network node 80 includes a component 800 configured to: communicate with the first network node using a first feeder link; receive a second message from the first network node to manage the control plane interface between the first and second network nodes, the second message including transport network layer (TNL) parameters associated with the second feeder link; initiate a second request to a third network node including the TNL parameters, so that the third network node switches the communication between the first and third network nodes to use the TNL parameters for a list of terminal devices connected to the first network node; and switch the communication between the first and second network nodes from the first feeder link to the second feeder link.

[0200] In an example embodiment of this disclosure, component 800 includes: at least one processor 802; and at least one memory 804 storing instructions that, when executed by at least one processor 802, cause a third network node 80 to perform the operations described above.

[0201] In exemplary embodiments of this disclosure, component 800 is also configured to perform methods according to any of the foregoing embodiments, such as Figure 4A , Figure 4B , Figure 4C , Figure 4D and Figure 6 The method shown.

[0202] Figure 9 This is a block diagram illustrating an example structure of a third network node according to an example embodiment of the present disclosure.

[0203] like Figure 9 As shown, the third network node 90 includes a component 900 configured to: receive from the second network node a second request including transport network layer (TNL) parameters associated with the second feeder link, so that the third network node updates communication for a list of terminal devices connected to the first network node; update stored information about the communication using the TNL parameters; and initiate the communication for the list of terminal devices connected to the first network node using the updated information about the communication.

[0204] In an exemplary embodiment of this disclosure, component 900 includes: at least one processor 902; and at least one memory 904 storing instructions that, when executed by at least one processor 902, cause a fourth node 90 to perform the operations described above.

[0205] In an exemplary embodiment of this disclosure, component 900 is also configured to perform a method according to any of the foregoing embodiments, such as Figure 5A , Figure 5B and Figure 6 The method shown.

[0206] Processors 702, 802, and 902 can be any type of processing component, such as one or more microprocessors or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, etc. Memory 704, 804, and 904 can be any type of storage component, such as read-only memory (ROM), random access memory, cache memory, flash memory, optical storage, etc.

[0207] Figure 10 This is a block diagram illustrating an apparatus / computer-readable storage medium according to embodiments of the present disclosure.

[0208] like Figure 10 As shown, computer-readable storage medium 100 stores instructions 101 that, when executed by at least one processor of a network node (such as a first, second, third, fourth, or fifth node), cause at least one processor of that node to perform a method according to any of the above embodiments, such as... Figure 3A , Figure 3B , Figure 3C , Figure 4A , Figure 4B , Figure 4C , Figure 4D , Figure 5A , Figure 5B and Figure 6 The method shown.

[0209] Furthermore, this disclosure may also provide a carrier containing the computer program / instructions described above. The carrier is an electronic signal, an optical signal, a radio signal, or one of the aforementioned computer-readable storage media. The computer-readable storage medium may be, for example, an optical disc or an electronic storage device such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, magnetic tape, CD-ROM, DVD, Blu-ray disc, etc.

[0210] Figure 11 This is a block diagram illustrating an example apparatus unit suitable for performing a method according to an embodiment of the present disclosure for a first network node.

[0211] like Figure 11 As shown, the first network node 110 may include: a communication unit 1102 for communicating with a second network node and a third network node using a first feeder link; an execution unit 1104 for performing feeder link switching by establishing a second feeder link; a transmission unit 1106 for transmitting a second message to the second network node to manage the control plane interface between the first network node and the second network node; and a switching unit 1108 for switching communication between the first network node and the second network node and / or communication between the first network node and the third network node to the second feeder link. The second message includes Transport Network Layer (TNL) parameters associated with the second feeder link.

[0212] In an exemplary embodiment of this disclosure, the first network node 170 is also configured to perform methods according to any of the foregoing embodiments, such as Figure 3A , Figure 3B , Figure 3C and Figure 6 The method shown.

[0213] Figure 12 This is a block diagram illustrating an example device unit suitable for performing a method according to an embodiment of the present disclosure for a second network node.

[0214] like Figure 12 As shown, the second network node 120 may include: a communication unit 1202 for communicating with the first network node using a first feeder link; a receiving unit 1204 for receiving a second message from the first network node to manage the control plane interface between the first network node and the second network node, the second message including transport network layer (TNL) parameters related to the second feeder link; an initiating unit 1206 for initiating a second request to a third network node including the TNL parameters, so that the third network node switches the communication between the first network node and the third network node to use the TNL parameters for a list of terminal devices connected to the first network node; and a switching unit 1208 for switching the communication between the first network node and the second network node from the first feeder link to the second feeder link.

[0215] In an exemplary embodiment of this disclosure, the second network node 120 is also configured to perform methods according to any of the foregoing embodiments, such as Figure 4A , Figure 4B , Figure 4C , Figure 4D and Figure 6 The method shown.

[0216] Figure 13 This is a block diagram illustrating an example device unit suitable for performing a method according to an embodiment of the present disclosure in a third network node.

[0217] like Figure 13 As shown, the third network node 130 may include: a receiving unit 1306, configured to receive from the second network node a second request including transport network layer (TNL) parameters associated with the second feeder link, so that the third network node updates communication for the list of terminal devices connected to the first network node; an updating unit 1308, configured to update stored information about the communication using the TNL parameters; and a starting unit 1310, configured to restore the communication for the list of terminal devices connected to the first network node using the updated information about the communication.

[0218] In an exemplary embodiment of this disclosure, the third network node 130 is also configured to perform methods according to any of the foregoing embodiments, such as Figure 5A , Figure 5B and Figure 6 The method shown.

[0219] The term “unit” can have a conventional meaning in the field of electronic, electrical and / or electronic equipment, and can include, for example, electrical and / or electronic circuits, devices, modules, processors, memories, logic solid-state and / or discrete devices, computer programs or instructions for performing corresponding tasks, processes, calculations, outputs and / or display functions, such as those described herein.

[0220] As used in this disclosure, the term "circuit" may refer to one or more of the following: (a) Hardware circuit implementation only (such as implementation in analog and / or digital circuits only) and (b) A combination of hardware circuitry and software, such as (if applicable): (i) A combination of (multiple) analog and / or digital hardware circuits and software / firmware, and (ii) Any part of the (multiple) hardware processors having software (including (multiple) digital signal processors), software, and (multiple) memories, working together to enable a device such as a mobile phone or server to perform various functions; and (c) (multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or portions thereof, which require software (e.g., firmware) to function, but may be absent if such software is not required for operation. This definition of "circuit" applies to all uses of the term in this disclosure, including its use in any claim. As another example, as used in this disclosure, the term "circuit" also covers only hardware circuitry or a processor (or processors) or a portion thereof, and an implementation thereof with accompanying software and / or firmware. The term "circuit" also covers, for example (if applicable) baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0221] Using these units, the device can function without a fixed processor or memory, and can be configured with any type of computing and storage resources from at least one node / device / entity / device associated with the communication system. Virtualization and network computing technologies (such as cloud computing) can also be introduced to improve the efficiency of network resource utilization and network flexibility.

[0222] The techniques described herein can be implemented through various components, such that the means for implementing one or more functions of the corresponding apparatus described in conjunction with the embodiments includes not only prior art components but also components for implementing one or more functions of the corresponding apparatus described in conjunction with the embodiments. The apparatus may include separate components for each individual function, or may include components configured to perform two or more functions. For example, these techniques can be implemented through hardware (one or more devices), firmware (one or more devices), software (one or more modules / units), or a combination thereof. For firmware or software, implementation can be achieved through modules (e.g., procedures, functions, etc.) that perform the functions described herein.

[0223] In some embodiments, some or all of the functions described herein may be provided by processing circuitry that executes instructions stored in memory, which may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functions may be provided by processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as those provided in a hard-wired manner. In any of these particular embodiments, the processing circuitry may be configured to perform the functions regardless of whether instructions stored on a non-transitory computer-readable storage medium are executed. The benefits provided by such functions are not limited to the processing circuitry itself or other components of the computing device, but are generally enjoyed by the computing device as a whole and / or by the end user and wireless network.

[0224] As used in this article, the term “non-transient” refers to a limitation on the medium itself (i.e., tangible, not signal), rather than a limitation on the persistence of data storage (e.g., RAM and ROM).

[0225] As described in the above exemplary embodiments of this disclosure, the embodiments herein have numerous advantages. According to embodiments of this disclosure, exemplary embodiments propose a mechanism that enables faster and more accurate pausing / resumption of communication in a communication network during feeder link switching. Data transmission interruptions or even losses caused by feeder link switching can be reduced.

[0226] It should be understood that the above embodiments are for illustrative purposes only and not for limitation. This disclosure may be implemented in ways different from those specifically set forth herein without departing from its essential characteristics. All changes to these embodiments without departing from the meaning and equivalent scope of the appended claims are intended to be included herein.

[0227] References The following are the references included in the entirety of this article: 3GPP TS 38.413 V17.6.0 (2023-09); 3GPP TS 23.401 V18.4.0 (2023-12); 3GPP TS 23.501 V18.4.0 (2023-12); 3GPP TS 23.502 V18.4.0 (2023-12); 3GPP TS 29.502 V18.4.0 (2023-09).

[0228] Abbreviation Explanation FLSO hard feeder link switching AMF Access and Mobility Management Functions DL downlink CP control plane UP User Interface SMF Session Management Function UPF User Face Functions NTN non-terrestrial networks LEO (Low Earth Orbit) NG Next Generation TNL Transport Network Layer AN access network TEID (Tunnel Endpoint Identifier) F-TEID (Fully Qualified Tunnel Endpoint Identifier)

Claims

1. A method (300) for feeder link switching in a communication network, performed by a first network node, comprising: Communicate with the second and third network nodes using the first feeder link (S302); The feeder link switching described in (S304) is performed by establishing a second feeder link; Transmit a second message (S306) to the second network node to manage the control plane interface between the first network node and the second network node; as well as Switch the communication between the first network node and the second network node and / or the communication between the first network node and the third network node to the second feeder link (S308); The second message includes Transmission Network Layer (TNL) parameters related to the second feeder link.

2. The method (300) according to claim 1, The feeder link switching described in (S304) includes: A first message is transmitted to the second network node (S3042) to indicate that the feeder link switch from the first feeder link to the second feeder link will be performed by the first network node.

3. The method (300) according to claim 2, The first message includes TNL parameters related to the first feeder link; The TNL parameters in the first message include: The TNL address of the first network node before the feeder link switch; as well as The TNL parameters in the second message include the TNL address of the first network node after the feeder link switch.

4. The method (300) according to claim 3, At least one of the first message or the second message further includes: The identifier ID of the first network node, and / or a list of at least one identifier of the terminal device connected to the first network node.

5. The method (300) according to claim 3 or 4, The TNL parameters in the second message also include: The mapping between the TNL address of the first network node before the feeder link switch and the TNL address of the first network node after the feeder link switch.

6. The method (300) according to any one of claims 2 to 5, The first message or the second message is a Next Generation Network (NG) Establishment Request Message, a Radio Access Network (RAN) Configuration Update Message, an S1 Establishment Request Message, an eNB Configuration Update Message, or an Application Protocol (AP) Message.

7. The method (300) according to any one of claims 2 to 6, The first feeder link includes a first gateway; The second feeder link includes a second gateway; and The first message further includes a time parameter, which indicates the time point at which the first feeder link becomes unavailable, and / or the time point at which the second feeder link becomes available, and / or the time period during which both the first feeder link and the second feeder link are available.

8. The method (300) according to any one of claims 2 to 7, The first network node transmits the first message and the second message to multiple second network nodes.

9. The method (300) according to any one of claims 1 to 8, further comprising: After transmitting the second message, control plane messages are received from the second network node via the second feeder link (S310) and / or user plane traffic is received from the third network node (S310).

10. The method (300) according to any one of claims 1 to 9, The first network node includes a base station; The second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); The third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW); and The communication between the first network node and the third network node includes user plane transmission that is paused before the feeder link switch and resumed after the feeder link switch.

11. The method (300) according to any one of claims 1 to 10, The communication network mentioned above is a non-terrestrial network.

12. A method (400) for feeder link switching in a communication network, performed by a second network node, comprising: Communicate with the first network node using the first feeder link (S402); Receive (S404) a second message from the first network node to manage the control plane interface between the first network node and the second network node, wherein the second message includes transport network layer (TNL) parameters related to the second feeder link; A second request including the transport network layer parameters is initiated to the third network node (S406) so that the third network node switches the communication between the first network node and the third network node to use the transport network layer parameters for a list of terminal devices connected to the first network node; as well as The communication between the first network node and the second network node is switched from the first feeder link to the second feeder link (S408).

13. The method (400) according to claim 12, The communication between the first feeder link and the first network node (S402) includes: Receive a first message (S4022) from the first network node to indicate that the feeder link switch from the first feeder link to the second feeder link will be performed by the first network node; as well as A first request (S4024) is initiated to a third network node to cause the third network node to suspend communication between the first network node and the third network node for the list of terminal devices connected to the first network node.

14. The method (400) according to claim 13, At least one of the first message or the first request includes: The TNL address of the first network node before the feeder link switch; as well as At least one of the TNL parameters in the second message or the TNL parameters in the second request includes: the TNL address of the first network node after the feeder link switch.

15. The method (400) according to claim 13 or 14, The first message, the second message, the first request, or the second request further includes: The identifier ID of the first network node, and / or a list of identifiers of at least one terminal device connected to the first network node.

16. The method (400) according to any one of claims 13 to 15, At least one of the TNL parameters in the second message or the TNL parameters in the second request further includes: The mapping between the TNL address of the first network node before the feeder link switch and the TNL address of the first network node after the feeder link switch.

17. The method (400) according to any one of claims 13 to 16, The first message or the second message is a Next Generation Network (NG) Establishment Request Message, a Radio Access Network (RAN) Configuration Update Message, an S1 Establishment Request Message, an eNB Configuration Update Message, or an Application Protocol (AP) Message.

18. The method (400) according to any one of claims 13 to 17, The first feeder link includes a first gateway; The second feeder link includes a second gateway; The first message further includes a time parameter, which indicates the time point at which the first feeder link becomes unavailable, and / or the time point at which the second feeder link becomes available, and / or the time period during which both the first feeder link and the second feeder link are available; and The first request includes a time parameter, which indicates the time point at which the third network node suspends the communication and / or the time period during which the third network node suspends the communication.

19. The method (400) according to any one of claims 13 to 18, further comprising: Upon receiving the first message, stop (S412) the transmission of control plane messages to the first network node via the first feeder link; as well as Upon receiving the second message, the transmission of control plane messages to the first network node via the second feeder link is resumed (S414).

20. The method (400) according to any one of claims 13 to 19, The second network node initiates the first request and the second request to multiple third network nodes.

21. The method (400) according to any one of claims 12 to 20, The first network node includes a base station; The second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); The third network node includes a User Plane Function (UPF) or a Serving Gateway (S-GW); and The communication includes user plane transmissions that are paused before the feeder link switch and resumed after the feeder link switch.

22. The method (400) according to claim 21, The first or second request initiated by the AMF includes: A service request including a list of terminal devices is made to the Session Management Function (SMF) via call (S416). as well as The SMF initiates an N4 request to the UPF, and the N4 request includes a list of identifiers for the list of terminal devices.

23. The method (400) according to any one of claims 12 to 22, The communication network mentioned above is a non-terrestrial network.

24. A method (500) for feeder link switching in a communication network, performed by a third network node, comprising: The third network node receives (S506) a second request including transport network layer (TNL) parameters from the second network node, so that the third network node updates the communication for the list of terminal devices connected to the first network node; The information about the communication stored is updated (S508) using the transport network layer parameters; as well as Using the updated information about the communication, the communication is initiated (S510) for the list of terminal devices connected to the first network node.

25. The method (500) according to claim 24, further comprising: The third network node receives a first request (S502) from the second network node, so that the third network node suspends the communication between the first network node and the third network node for the list of terminal devices connected to the first network node; as well as For the list of terminal devices connected to the first network node, the communication between the first network node and the third network node is suspended (S504).

26. The method (500) according to claim 25, The first request includes: The TNL address of the first network node before the feeder link switch; as well as The TNL parameter in the second request includes the TNL address of the first network node after the feeder link switch.

27. The method (500) according to claim 26, At least one of the first request or the second request further includes: The identifier ID of the first network node, and / or a list of at least one identifier of the terminal device connected to the first network node.

28. The method (500) according to claim 26 or 27, The TNL parameter in the second request also includes: A mapping from the TNL address of the first network node before the feeder link switch to the TNL address of the first network node after the feeder link switch.

29. The method (500) according to any one of claims 25 to 28, The first request includes a time parameter, which indicates the time point at which the third network node suspends the communication and / or the time period during which the third network node suspends the communication.

30. The method (500) according to any one of claims 24 to 29, The stored information includes at least the user plane transport network layer address of the user plane tunnel for the terminal device connected to the first network node.

31. The method (500) according to any one of claims 24 to 30, The third network node updates at least one IP address for the next-generation user plane NG-U tunnel associated with the first network node, based at least on the second request.

32. The method (500) according to any one of claims 24 to 31, The first network node includes a base station; The second network node includes an Access and Mobility Management Function (AMF) or a Mobility Management Entity (MME); The communication mentioned therein includes user plane transmissions that are paused before the feeder link switch and resumed after the feeder link switch; The communication is restored by using a transmission network layer (TNL) connection of the second feeder link; and The third network node includes a User Plane Function (UPF) or a Service Gateway (S-GW).

33. The method (500) according to claim 32, The first or second request received by the UPF is an N4 request transmitted by the Session Management Function (SMF), and The SMF transmits the N4 request as a response to receiving a service request including a list of terminal device identifiers from the AMF.

34. The method (500) according to any one of claims 24 to 33, The communication network mentioned above is a non-terrestrial network.

35. A first network node (70) comprising a component (700) configured to: Communicate with the second and third network nodes using the first feeder link; The feeder link switching is performed by establishing a second feeder link; Transmit a second message to the second network node to manage the control plane interface between the first network node and the second network node; as well as Switch the communication between the first network node and the second network node and / or the communication between the first network node and the third network node to the second feeder link; The second message includes Transmission Network Layer (TNL) parameters related to the second feeder link; The component (700) mentioned above includes: At least one processor (702); as well as At least one memory (704) stores instructions that, when executed by the at least one processor (702), cause the first network node (70) to perform the above-described operations.

36. The first network node (70) according to claim 35, wherein the component (700) is further configured to perform the method according to any one of claims 2 to 11.

37. A second network node (80) comprising a component (800) configured to: Communicate with the first network node using the first feeder link; Receive a second message from the first network node to manage the control plane interface between the first network node and the second network node, wherein the second message includes transport network layer (TNL) parameters related to the second feeder link; as well as A second request, including the transport network layer parameters, is initiated to the third network node so that the third network node switches the communication between the first network node and the third network node to use the transport network layer parameters for a list of terminal devices connected to the first network node. as well as Switch the communication between the first network node and the second network node from the first feeder link to the second feeder link; The component (800) mentioned above includes: At least one processor (802); as well as At least one memory (804) stores instructions that, when executed by the at least one processor (802), cause the second network node (80) to perform the above-described operations.

38. The second network node (80) according to claim 37, wherein the component (800) is further configured to perform the method according to any one of claims 13 to 23.

39. A third network node (90) comprising a component (900) configured to: The third network node receives a second request, including transport network layer (TNL) parameters associated with the second feeder link, from the second network node, so that the third network node updates communications for the list of terminal devices connected to the first network node. The stored information about the communication is updated using the transport network layer parameters. as well as Using the updated information about the communication, the communication is initiated for the list of terminal devices connected to the first network; The components mentioned above include: At least one processor (902); as well as At least one memory (904) stores instructions that, when executed by the at least one processor (902), cause the third network node (90) to perform the above-described operations.

40. The third network node (90) according to claim 39, wherein the component (900) is further configured to perform the method according to any one of claims 25 to 34.

41. A computer-readable storage medium (100) storing instructions (101) that, when executed by at least one processor of a network node, cause the at least one processor of the network node to perform the method according to any one of claims 1 to 34.

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