Satellite access method and system

Abstract

The embodiment of the invention discloses a satellite access method. A first spaceborne radio access node receives signaling messages from user equipments (UEs) in a group of UEs. The signaling message indicates a change in a currently served spaceborne radio access node of the UE group. And the first satellite-borne wireless access node forwards the signaling message to a ground network node so as to trigger switching of the UE group from the first satellite-borne wireless access node to the second satellite-borne wireless access node. The handover of the UE group is based on per UE group signaling, which includes a request message to request a second spaceborne radio access node to establish, modify, or release a bearer context for the UE group, or to establish, modify, or release resources for a session associated with the UE group.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of communication systems, and more specifically, to a satellite access method and system. BACKGROUND

[0002] Non-Terrestrial Network (NTN) can extend the coverage of 5G New Radio (NR) to remote and rural areas where terrestrial networks are not feasible or cost-effective, as well as to maritime and airspaces.

[0003] NTN can improve the reliability and resilience of 5G NR by providing backup or backup links in the event of ground network failure or congestion. In addition, NTN can bring new business opportunities and innovation for 5G service providers, network operators, satellite operators and end users by creating a converged and integrated network environment.

[0004] TECHNICAL PROBLEM According to the current standardization progress (i.e., 3GPP RAN#101 and SA#101 meetings for Release 19), studying NTN regenerative payload generic architecture has become a direction, in which a satellite gNB will be deployed on a satellite. In this architecture, when the gNB or gNB Distributed Unit (gNB-DU) is located on the satellite, and the satellite constellation is constantly moving, the ground station (GS) must locate a new satellite gNB Central Unit (gNB-CU) / gNB-DU approximately every few minutes (e.g., about 7-8 minutes for LEO category) in order to facilitate the handover of user equipment (UE).

[0005] For the scenario of gNB-DU deployed on the satellite, when the satellite constellation moves, the satellite gNB-DU / CU serving the UE will move away from the corresponding ground gNB-CU or User Plane Function (UPF). This situation requires a new type of update to be implemented for the F1 / NG-U tunnel, which can be based on per-UE group or per-gNB-DU / CU. In addition, this scenario can result in the need to modify the Protocol Data Unit (PDU) / multicast / broadcast session or context and handover. However, the existing 5G NR protocol currently does not support the signaling related to the modification of the PDU / multicast / broadcast session or context based on per-UE group, nor the handover signaling involving the UE group.

[0006] Furthermore, when the serving on-board gNB-DU / CU node changes, all or most of the UEs under this on-board gNB-DU / CU node have to be handed over to the new node simultaneously. This type of handover will cause huge signaling overhead on the F1-C and NG-C control plane interfaces connecting the on-board and ground network nodes. This is especially true for the current 5G NR protocol signaling, which is mainly designed for single UE signaling for tasks such as PDU / multicast / broadcast session context modification and / or handover signaling. SUMMARY

[0007] It is an object of the present disclosure to propose a satellite access method and system.

[0008] In a first aspect, one embodiment of the present application provides a satellite access method, comprising: a user equipment, UE, sending a signaling message indication to a first on-board wireless access node and / or a ground network node, wherein the signaling message indication indicates a change of a currently serving on-board wireless access node; the first on-board wireless access node and / or the ground network node dividing the UE into different UE groups based on the signaling message indication from the UE; and the first on-board wireless access node and / or the ground network node triggering a handover of at least one UE group from the first on-board wireless access node to a second on-board wireless access node, wherein the handover of the at least one UE group is based on the signaling message indication from the UE and / or a per UE group signaling message provided by the first on-board wireless access node and / or the ground network node.

[0009] In a second aspect, one embodiment of the present application provides a network system, comprising: a user equipment, UE; a first on-board wireless access node; and a ground network node; wherein the user equipment, UE, is configured to send a signaling message indication to the first on-board wireless access node and / or the ground network node, wherein the signaling message indication indicates a change of a currently serving on-board wireless access node; the first on-board wireless access node and / or the ground network node is configured to divide the UE into different UE groups based on the signaling message indication from the UE; the first on-board wireless access node and / or the ground network node is configured to trigger a handover of at least one UE group from the first on-board wireless access node to a second on-board wireless access node; and The switching of the at least one UE group is based on a signaling message indication from the UE and / or a per UE group signaling message provided by the first satellite borne wireless access node and / or a ground network node.

[0010] In a third aspect, one embodiment of the present application provides a base station comprising a processor configured to invoke and run a computer program stored in a memory to cause the device in which the processor is installed to perform the disclosed method.

[0011] The disclosed method can be programmed as computer executable instructions stored in a non-transitory computer readable medium. When loaded into a computer, the non-transitory computer readable medium instructs the processor of the computer to perform the disclosed method.

[0012] The non-transitory computer readable medium can include at least one selected from the group consisting of a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory, and a flash memory.

[0013] The disclosed method can be programmed as a computer program product that causes a computer to perform the disclosed method.

[0014] The disclosed method can be programmed as a computer program that causes a computer to perform the disclosed method.

[0015] Advantages The present disclosure provides a method for supporting satellite access with on-board radio access node functionality. The benefits and innovative aspects of the present disclosure include: The present disclosure introduces new signaling and procedures related to per-UE group session or context management and switching. These enhancements aim to mitigate the signaling overload issue within the Fl-C and NG-C control plane interfaces.

[0016] The present disclosure also introduces a new set of signaling, indications, and triggers designed to enable per-UE group session or context management and switching signaling, especially in scenarios where the access node is located on a satellite. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present specification, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present specification, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0018] Figure 1 A schematic diagram of a network system with a satellite supported NR-RAN is shown.

[0019] Figure 2 A schematic diagram of a network system with UE groups is shown.

[0020] Figure 3 A schematic diagram of one embodiment of a satellite access method is shown.

[0021] Figure 4 A schematic diagram of signaling of a handover triggered by a satellite changing or a satellite radio access node moving is shown.

[0022] Figure 5 A schematic diagram of one embodiment of a network system with partial satellite radio access nodes is shown.

[0023] Figure 6 A schematic diagram of signaling of a handover triggered by a partial satellite radio access node moving is shown.

[0024] Figure 7 A schematic diagram of one embodiment of a network system with full satellite radio access nodes is shown.

[0025] Figure 8 A schematic diagram of signaling of a handover triggered by a full satellite radio access node moving is shown.

[0026] Figure 9 A schematic diagram of a user equipment (UE) is shown.

[0027] Figure 10 A schematic diagram of a network node is shown.

[0028] Figure 11 A schematic diagram of a chip executing the disclosed methods in a UE is shown.

[0029] Figure 12 A schematic diagram of a chip executing the disclosed methods in a network node is shown. DETAILED DESCRIPTION

[0030] The technical content, structural features, achieved purposes and effects of the embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. Specifically, the terms in the embodiments of the present disclosure are only for the purpose of describing specific embodiments, and are not intended to limit the present disclosure.

[0031] The abbreviations used in the specification are listed as follows: Table 1

[0032]

[0033] In the specification, a node installed on a satellite can be referred to simply as a spaceborne node. Thus, a gNB installed on a satellite can be referred to simply as a spaceborne gNB. Similarly, a gNB-DU installed on a satellite can be referred to simply as a spaceborne gNB-DU.

[0034] The present disclosure introduces new signaling and procedures for PDU / multicast / broadcast session or context modification / update / release and / or handover to handle the signaling overload problem in the F1-C and NG-C control plane interfaces. In addition, the present disclosure also introduces a new set of signaling and triggers to help enable per-UE group session or context modification / update / release and / or per-UE group handover procedures, especially in the scenario where the access nodes are located on satellites.

[0035] The development of 5G services over satellite constellations has been done in coordination within the 3GPP Radio Access Network (RAN) and System Architecture (SA) working groups. Currently, there is a direction in the RAN and SA working groups to study the support of NTN for regenerative payload architectures.

[0036] A transparent satellite access network consisting of a satellite payload implements frequency translation and radio frequency amplifiers in the uplink and downlink directions. The satellite operates as an analog RF repeater, relaying the NR-Uu radio interface from the feeder link (between the NTN gateway and the satellite) to the service link (between the satellite and the User Equipment (UE)) and vice versa. The satellite radio interface (SRI) used on the feeder link is NR-Uu. In other words, the satellite does not terminate NR-Uu, it just relays it. Different transparent satellites can be connected to the same gNB on the ground.

[0037] For the case of regenerative satellite access, the satellite can have some functions of the 5GS. One implementation is when the satellite payload can implement a complete gNB supporting satellite-enabled NR-RAN or a gNB-DU deployed on board as shown in Figure 1 The SRI transports N1 (NAS) / N2 (NG-C) / N3 (NG-U) interfaces between the terrestrial 5G Core Network (CN) and the on-board gNB-CU.

[0038] Reference is made to Figure 1CN 300 is connected to the ground network 200 of the RAN. The CN 300 can comprise an LTE CN or a 5GC, which can include a User Plane Function (UPF) 30b, a Session Management Function (SMF) 30d, an Access and Mobility Management Function (AMF) 30c. The CN 300 can also include other network functions, such as a Unified Data Management (UDM), a Policy Control Function (PCF), a Control Plane (CP) / User Plane (UP) Separation (CUPS), an Authentication Server (AUSF), a Network Slice Selection Function (NSSF), and a Network Exposure Function (NEF).

[0039] The UPF 30b is connected to a Data Network (DN) 40. The AMF 30c is connected to the gNB-CU 20-1c through interfaces N1 and N2. The gNB-CU 20-1c is connected to the on-board gNB-DU 20-2c. The on-board gNB 20b can be connected to the ground network 200 through a ground gateway. The ground network 200 can include other base stations, such as gNB 20d. For example, the UE 10a and the UE 10b are within the coverage of the on-board gNB 20b. The UE 10b is within the coverage of the gNB 20d.

[0040] Figure 2A satellite wireless system for providing multicast, broadcast and / or unicast services to a plurality of wireless devices or UEs (e.g., UEs 10a-10g) according to the methods of the present disclosure is shown. The UEs (e.g., UEs 10a-10g) are connected to one or more satellite radio access nodes, e.g., first and second satellite-borne radio access nodes 201 and 202, over a first radio interface (Uu). A single satellite radio access node can comprise two nodes interconnected over a user plane internal network interface (F1-U) and a first control plane internal network interface (F1-C). One of these nodes can be deployed on a satellite, while the other is located on the ground. At least one satellite radio access node is connected to a UPF over an NG-U interface and to an AMF over a second control plane internal network interface NG-C. The UPF is connected to a DN 40 to provide respective multicast, broadcast and / or unicast services to the UEs.

[0041] In the wireless system, as the satellite constellation moves, the satellite-borne radio access node providing coverage to the UEs will rotate away from the respective ground network node. Then, a new satellite-borne radio access node will take over or share the coverage to the UEs. As shown, this situation results in three types of UE coverage: Figure 2 1. UEs in group 1 (e.g., UEs 10a, 10b and 10c) are under the coverage of the old / source satellite-borne radio access node.

[0042] 2. UEs in group 2 (e.g., UEs 10d and 10e) are within the overlapping coverage area of the old / source and new / target satellite-borne radio access nodes.

[0043] 3. UEs in group 3 (e.g., UEs 10f and 10g) are under the coverage of the new / target satellite-borne radio access node.

[0044] ​To ensure efficient utilization of the F1-U and NG-U user plane interfaces, the UEs in group 2, and ideally the UEs in group 2 and group 3, must be transitioned to the F1-U and NG-U user plane interfaces with the new / target on-board satellite wireless access node. However, moving such a group of UEs to the new interface simultaneously will require a very large number of signaling messages on the F1-C and NG-C control plane interfaces connecting the on-board satellite and ground network nodes. This is especially true for the current 5G NR protocol signaling, which is mainly designed for single UE signaling for tasks such as PDU / multicast / broadcast session context modification and / or handover signaling. The following sections introduce new per-UE group session or context management, e.g., UE F1 / NG-U tunnel management, PDU / multicast / broadcast session or context modification / update / release and / or handover related signaling and procedures, to handle the signaling overload problem in the F1-C and NG-C control plane interfaces. In addition, this section also introduces a new set of signaling, indications, and triggers to help enable per-UE group session or context modification / update / release and / or per-UE group handover to handle scenarios where the access node is on a satellite.

[0045] The present disclosure proposes a method to address the challenges related to session management, mobility / handover, bearer change, and node reselection to enable efficient fronthaul or backhaul traffic routing. It also covers load balancing, QoS guarantee, and coverage guarantee for wireless devices receiving unicast, multicast, or broadcast sessions or services over a converged wireless network including terrestrial and satellite radio access. The method includes: (1). A set of control plane signaling, triggers, and indications from wireless devices and / or on-board satellite or ground network nodes to ground control nodes (e.g., gNB-CU / AMF) to help enable efficient PDU / multicast / broadcast context modification and / or handover related signaling in scenarios where satellite radio access nodes are deployed on satellites.

[0046] (2). A new system and procedure with group-based triggers and signaling to handle data forwarding for groups of user equipment (UEs) when on-board satellite nodes change, or during handover and session / context update. The system aims to ensure that the requirements for scenarios involving mobile satellite radio access nodes are met, while also addressing the signaling overload problem and optimizing fronthaul / backhaul traffic routing and load balancing.

[0047] The detailed description of the method is given in the following sections.

[0048] Figure 4A method of supporting satellite access with on-board radio access nodes and / or ground-based access is introduced, where due to the continuous movement of the satellite constellation, the on-board radio access nodes are in frequent movement, resulting in different groups of UEs being in different coverage types: 1. UEs in group 1 are under coverage of the old on-board radio access node.

[0049] 2. UEs in group 2 are in the overlapping coverage area of the old and new on-board radio access nodes.

[0050] 3. UEs in group 3 are under coverage of the new on-board radio access node.

[0051] In at least one embodiment of the present disclosure, a certain wireless device (or UE) in a UE group sends a signaling message to the first on-board radio access node 201 (e.g., the old / source on-board radio access node) that is currently serving these UEs. The signaling message can be periodic, or determined by network pre-configured parameters (e.g., UE location or satellite ephemeris data). The signaling message can be an access stratum (AS) message or a non-access stratum (NAS) message, to explicitly or implicitly indicate that the on-board radio access node serving the wireless device (or UE) is changing, to assist the network for efficient mobility and resource management. The signaling message can include at least one of the following: coverage group type change, reference location change, reference time change, coverage or measurement change, frequency change, physical cell identity (PCI) change, satellite access related system information block (SIB) change, satellite ID change, UE session access type change, or other related information.

[0052] Upon receiving the signaling message from the user equipment (UE), the first on-board radio access node 201 (e.g., the old / source on-board radio access node) can divide the UEs into different UE groups based on the signaling, and then can forward the signaling message to the ground network nodes (e.g., ground radio access nodes and / or ground network control plane nodes) via the first or second control plane internal network interfaces based on one or more of the following: information within the message, coverage group type, and other related information of the UEs.

[0053] The ground network nodes (e.g., ground radio access nodes and / or ground network nodes) can use per-UE group signaling of Uu / NG / XnAP / F1AP / E1AP messages associated with the UE groups on the associated logical Uu / NG / Xn / F1 / E1 interfaces. These messages include one or more of the following messages: 1. Handover related signaling between the ground network node and the first satellite-based radio access node 201 (e.g., old / source satellite-based radio access node). For example, the handover related signaling can comprise one or more of the following: a handover indication, a handover command, and handover required information, of the session context and / or bearer context associated with the UE group, sent to the first satellite-based radio access node 201 (e.g., old / source satellite-based radio access node).

[0054] 2. Inter-satellite-based radio access node handover signaling between the first satellite-based radio access node 201 and the second satellite-based radio access node 202. For example, the inter-satellite-based radio access node handover signaling can comprise exchanging handover request and response messages for establishing / modifying / releasing the session context and / or bearer context associated with the UE group, indicated over the control plane internal network interface.

[0055] 3. Handover configuration related signaling between the first satellite-based radio access node 201 and the UE group. For example, the handover related signaling can comprise a group-based Radio Resource Control (RRC) message scrambled with a group Radio Network Temporary Identifier (RNTI), sent to the UE group indicated in the handover request. For example, the group-based RRC message comprises a per-UE group RRC reconfiguration message scrambled with the group-based RNTI to indicate when to stop data transmission for the UE group that has indicated an on-board access type change and to provide access related configuration information of the second satellite-based radio access node 202 (e.g., new / target satellite-based radio access node).

[0056] 4. Path handover related signaling between the second satellite-based radio access node 202 (e.g., new / target satellite-based radio access node) and the ground network node. For example, the path handover related signaling can comprise a path handover request and an acknowledgement to the path handover request for the session context and / or bearer context associated with the UE group, indicated in the first control plane internal network interface.

[0057] 5. Core network session update related signaling between the ground network node and a network entity (e.g., a Data Network (DN) 40 or a User Plane Function (UPF) node 30b) to handover the NG-U / tunnel user plane of the session context and / or bearer context associated with the UE group, provided in the first control plane internal network interface, between peer NG / Xn / F1 / E1 nodes.

[0058] In some embodiments of the disclosure, the ground network node can be an Access and Mobility Management Function (AMF) (e.g., AMF 30c), a gNB-Central Unit (gNB-CU), and / or a gNB. The first space-borne wireless access node 201 (e.g., old / source space-borne wireless access node) can be a full-satellite gNB, a gNB-CU, or a gNB-Distributed Unit (gNB-DU). The second space-borne wireless access node 202 (e.g., new / target space-borne wireless access node) can be a full-satellite gNB, a gNB-CU, or a gNB-DU. Embodiments of the disclosure can be applied to the following scenarios.

[0059] Partial-satellite radio access node scenario: In this scenario, a part of the radio access node (e.g., gNB-DU) is deployed on the satellite, while another part of the radio access node (e.g., gNB-CU) is deployed on the ground.

[0060] Full-satellite radio access node scenario: In this scenario, one radio access node is fully integrated on the satellite.

[0061] Reference Figure 3 In a network system, a satellite access method is performed. A user equipment (UE) sends a signaling message indication to a first space-borne wireless access node 201 and / or a ground network node (A001). The signaling message indication indicates a change of a currently serving space-borne wireless access node. The first space-borne wireless access node 201 receives the signaling message from the UEs in a UE group.

[0062] The first space-borne wireless access node 201 and / or the ground network node divides the UEs into different UE groups based on the signaling message indication from the UEs (A002).

[0063] The first space-borne wireless access node 201 and / or the ground network node triggers a handover of at least one UE group from the first space-borne wireless access node 201 to a second space-borne wireless access node 202, wherein the handover of the at least one UE group is based on the signaling message indication from the UEs and / or a per-UE group signaling message provided by the first space-borne wireless access node 201 and / or the ground network node (A003). These operations A001, A002, and A003 can be performed independently, sequentially, or in combination with each other.

[0064] In some embodiments of the disclosure, the ground network node, the first space-borne wireless access node 201, and / or the second space-borne wireless access node 202 initiates a per-UE group establishment, addition, modification, and / or release of a bearer context and / or session resource associated with the at least one UE group.

[0065] In some embodiments of the disclosure, the first space-borne wireless access node 201 sends, to at least one UE group, a per-UE group switching signaling indicating a switch to the second space-borne wireless access node 202.

[0066] In some embodiments of the disclosure, the ground network node is an Access and Mobility Management Function (AMF) and / or a Centralized Unit of a base station (gNB-CU).

[0067] In some embodiments of the disclosure, each UE group signaling message is a message provided from the space-borne wireless access node to the ground network node.

[0068] In some embodiments of the disclosure, the signaling message indication from the UE is a Non-Access Stratum (NAS) message provided from the UE to the ground network node, wherein the signaling message indication is a preconfigured parameter including a UE location or satellite ephemeris data. In some embodiments of the disclosure, the NAS message conveys an indication of a Protocol Data Unit (PDU), a join, modification, or update of a multicast or broadcast session, and an access type change of at least one UE group.

[0069] In some embodiments of the disclosure, the signaling message indication from the UE is a Radio Resource Control (RRC) configuration message.

[0070] In some embodiments of the disclosure, the signaling message indication and / or each UE group signaling message includes at least one of the following: a coverage group type change, a reference location change, a reference time change, a coverage and / or measurement change, a frequency change, a physical cell identity change, a satellite access related System Information Block (SIB) change, a satellite ID change, a UE session access type change, and / or other associated information.

[0071] In some embodiments of the disclosure, the signaling message indication and / or each UE group signaling message includes one or more of the following: a measurement of one or both of the first space-borne wireless access node 201 and the second space-borne wireless access node 202; an indication of a physical cell identity (PCI) of one or both of the first spaceborne wireless access node 201 and the second spaceborne wireless access node 202; and an indication indicating that a currently serving spaceborne wireless access node of the UE has changed.

[0072] In some embodiments of the disclosure, the session associated with the at least one UE group comprises a PDU session or a Multimedia Broadcast / Multicast Service (MBS) session.

[0073] In some embodiments of the disclosure, the method further comprises transmitting, from the first spaceborne wireless access node 201 to the at least one UE group, a group-based RRC message scrambled with a group Radio Network Temporary Identifier (RNTI).

[0074] In some embodiments of the disclosure, the group-based RRC message comprises a per-UE group RRC reconfiguration message scrambled with the group-based RNTI to indicate when to stop data transmission for the at least one UE group for which the on-board access type change has been indicated, and / or to provide access-related configuration information of the second spaceborne wireless access node 202.

[0075] In some embodiments of the disclosure, the method further comprises transmitting, by the second spaceborne wireless access node 202 to a ground network node, a path switch request to request a path switch of a bearer context or a session for the at least one UE group.

[0076] In some embodiments of the disclosure, the first spaceborne wireless access node 201 comprises a first on-board distributed unit of a base station; the second spaceborne wireless access node 202 comprises a second on-board distributed unit of the base station; and the ground network node comprises a ground centralized unit of the base station.

[0077] In some embodiments of the disclosure, the first on-board distributed unit transmits a single uplink (UL) Radio Resource Control (RRC) message transfer message to the ground centralized unit of the base station, the UL RRC message transfer message comprising all bearer contexts associated with the at least one User Equipment (UE) group for which the on-board access type change is indicated.

[0078] In some embodiments of the disclosure, the ground centralized unit of the base station sends a per-UE group context setup request message to the second on-board distributed unit of the base station to create a bearer context associated with at least one UE group indicating an on-board access type change, and to establish a related data bearer for the at least one UE group; and the second on-board distributed unit of the base station responds to the ground centralized unit of the base station with a per-UE group context setup response message.

[0079] In some embodiments of the disclosure, the ground centralized unit of the base station sends a per-UE group context modification request message to the first on-board distributed unit; the per-UE group context modification request message includes a per-UE group RRC reconfiguration message scrambled with a group-based Radio Network Temporary Identifier (RNTI); the per-UE group RRC reconfiguration message is used to indicate when to stop data transmission of at least one UE group indicating an on-board access type change, and / or to provide access-related configuration information of the second on-board distributed unit of the base station; and the first on-board distributed unit forwards the received per-UE group scrambled RRC reconfiguration message to the at least one UE group according to the indication of the on-board access type change of the at least one UE group, and responds to the ground centralized unit of the base station with a per-UE group context modification response message.

[0080] In some embodiments of the disclosure, the access-related configuration information of the second on-board distributed unit of the base station includes one or more of the following: a second gNB-DU ID, a cell ID, a new group-based RNTI, a second gNB security algorithm identifier for a selected security algorithm, and / or random access channel (RACH) resources, an association between RACH resources and one or more synchronization signal blocks (SSBs), an association between RACH resources and one or more UE-specific channel state information (CSI)-reference signals (RS) configurations, common RACH resources, and / or system information of the second cell.

[0081] In some embodiments of the disclosure, the UE in the at least one UE group responds to the second on-board distributed unit of the base station with an RRC reconfiguration complete message; and the second on-board distributed unit of the base station sends a UL RRC message transmission report to the ground centralized unit of the base station to convey the received RRC reconfiguration complete message.

[0082] In some embodiments of the disclosure, the ground centralized unit of the base station sends a per-UE group context release command message to the first on-board distributed unit to release at least one UE group indicating an on-board access type change; and the first on-board distributed unit releases the bearer context associated with the at least one UE group indicating the on-board access type change and responds to the ground centralized unit of the base station with a UE context release complete message.

[0083] In some embodiments of the disclosure, the first spaceborne wireless access node 201 comprises a first on-board base station; the second spaceborne wireless access node 202 comprises a second on-board base station; and the ground network node comprises an access and mobility management function (AMF).

[0084] In some embodiments of the disclosure, the first on-board base station triggers a handover request to the second on-board base station node to initiate group-based resource setup, modification or release for Protocol Data Unit (PDU) and / or Multicast / Broadcast Service (MBS) sessions associated with at least one UE group indicating an on-board access type change; the second on-board base station responds to the handover request from the first on-board base station by setting up, modifying or requesting release of resources for PDU and / or MBS session contexts associated with the at least one UE group indicated in the handover request from the first on-board base station; and based on the response from the second on-board base station, the first on-board base station triggers a Uu handover by sending a group RNTI scrambled group-based RRC message to the at least one UE group indicated in the handover request.

[0085] In some embodiments of the disclosure, the second on-board base station triggers an N2 path handover request to the AMF to inform the AMF that the plurality of at least one UE group has moved to the cell of the second on-board base station, the N2 path handover request comprising a list of PDU / MBS sessions to be handed over for the plurality of at least one UE group indicated in the handover request.

[0086] In some embodiments of the disclosure, the scrambled group-based RRC message comprises one or more of the following: a second gNB cell ID, a new C-RNTI (Cell-RNTI), a second gNB security algorithm identifier for a selected security algorithm, and / or dedicated random access channel (RACH) resources, an association between RACH resources and one or more synchronization signal blocks (SSBs), an association between RACH resources and one or more UE-specific channel state information (CSI)-reference signal (RS) configurations, common RACH resources, and / or system information of the second cell.

[0087] In some embodiments of the disclosure, the AMF sends an update SM context request to a Session Management Function (SMF) to request the SMF to update Session Management (SM) context for respective PDU / MBS sessions of the plurality of at least one UE group; the update SM context request includes a list of PDU / MBS sessions related to the plurality of at least one UE group indicated in the N2 path switch request; for the list of PDU / MBS sessions related to the plurality of at least one UE group indicated in the N2 path switch request, the SMF sends an N4 session modification request message to a User Plane Function (UPF); the UPF switches paths of PDU / MBS sessions related to the plurality of at least one UE group indicated in the N2 path switch request to the second satellite base station and returns an N4 session modification response message to the SMF, the N4 session modification response message indicating that the paths of PDU / MBS sessions related to the plurality of at least one UE group indicated in the N2 path switch request are switched; and the SMF sends an update SM context response to the AMF, the update SM context response indicating PDU / MBS sessions related to the plurality of at least one UE group that have been successfully switched.

[0088] In some embodiments of the disclosure, the AMF sends a path switch request acknowledgement to the second satellite base station, the acknowledgement indicating that a list of PDU / MBS sessions related to the plurality of at least one UE group indicated in the N2 path switch request have been successfully switched to a new N3 interface connecting the second satellite base station to the core network; and based on the path switch request acknowledgement from the AMF, the second satellite base station confirms the success of the switch by sending a request to the first satellite base station to release resources associated with PDU / MBS sessions related to the plurality of at least one UE group that have been successfully switched or handed over.

[0089] Part of the on-board radio access node: Embodiments of the present disclosure can be applied to the scenario where part of the radio access node is deployed on a satellite. For example, a gNB central unit (gNB-CU) is deployed on the ground, while a gNB distributed unit (gNB-DU) is deployed on a satellite. The gNB-CU and gNB-DU are connected through multiple F1-C / F1-U interfaces. The gNB-CU on the ground can be connected to another gNB-CU through an E1 interface.

[0090] In this particular scenario, when the satellite constellation moves, the gNB-DU will move away from the associated gNB-CU. This results in frequent updating of F1 tunnels, modification of UE / multicast / broadcast bearers or contexts, and potential signaling for gNB-DU switching for each individual UE connection.

[0091] To solve this problem, the on-board gNB-DU and / or the ground gNB-CU can group UEs based on indication messages from UE groups, coverage group types, and / or other related information, and implement per-UE group modification of PDU / multicast / broadcast bearers and contexts and / or gNB-DU switching signaling. As shown in the example of Figure 5 UEs 10a-10c are divided into group 1. UEs 10d-10e are divided into group 2. UEs 10f-10g are divided into group 3.

[0092] Reference Figure 6 The signaling between entities in the network system is detailed as follows. Examples of UEs 10 can include UEs 10a-10g.

[0093] The UE is configured by the first on-board wireless access node 201 (e.g., old / source on-board wireless access node) to send RRC signaling to report one or more instances of the following: (1). Measurements of one or both of the first on-board wireless access node 201 and the second on-board wireless access node 202; (2). Indication of the physical cell identity (PCI) of one or both of the first on-board wireless access node 201 and the second on-board wireless access node 202; and (3). Indication that the UE's current serving on-board wireless access node has changed.

[0094] A UE located in the overlapping region between the first and second satellite-based radio access nodes 201, 202 or a UE capable of receiving a new satellite-related access system information block (SIB) can generate the report. An example of an indication showing a physical cell identity (PCI) or showing a change of the currently serving satellite-based radio access node is provided in Table 2 below. The SIB change indication reported by the UE in group 2 indicates a change of the currently serving satellite-based radio access node by conveying two PCIs, i.e., [PCI, PCI2].

[0095] Table 2

[0096] Optionally, the UE can decide to send a non-access stratum (NAS) signaling to the AMF 30c based on pre-configured parameters from the network, e.g., UE location or satellite ephemeris data. For example, the NAS signaling conveys a protocol data unit (PDU), a join, modification or update of a multicast or broadcast session, or an indication of an access type change of a UE group. Referring to TS 29.502, the access type change indicates that the access type of a PDU, multicast or broadcast session has changed, e.g., from non-3GPP access to 3GPP access or from 3GPP access to non-3GPP access. Table 3 below shows an example of an explicit session access type change indication.

[0097] Table 3

[0098] Optionally, the AMF 30c can determine to send a handover trigger indication based on the NAS signaling from the UE or its internal configuration. The internal configuration can include factors such as UE location, satellite ephemeris, or a change of radio access technology (RAT) information type indicated by the first satellite-based radio access node 201 (e.g., old / source satellite-based radio access node) for a UE group or a session of a UE, as described in Option 1 or 2.

[0099] Option 1: As indicated by the RAT information, the UEs in group 1 do not change the satellite access type, while the UEs in group 2 and group 3 change the satellite access type. Tables 4 and 5 below show examples of an indication indicating a change of RAT information type.

[0100] Table 4

[0101] Option 2: As indicated by the RAT information, the UEs in group 1 and group 2 do not change the satellite access type, while the UEs in group 3 change the satellite access type.

[0102] Table 5

[0103] Reference Figure 6 Upon receiving the signaling message indication from the UE, the first space-borne wireless access node 201 and / or the ground network node divides the UEs into different UE groups based on the signaling message indication from the UE. The signaling message indication from the UE can be a radio resource control (RRC) configuration message. The first space-borne gNB-DU 20-21a can be the source space-borne gNB-DU 20-21a. The ground network node can be the AMF 30c and / or the ground gNB-CU 20-1a. As shown in the example of FIG. 3, the UEs 10a-10c are divided into group 1. The UEs 10d-10e are divided into group 2. The UEs 10f-10g are divided into group 3. Figure 5

[0104] Based on the RRC signaling from the UE, or the indication from the ground gNB-CU 20-1a of the gNB-DU handover trigger, or the indication from the AMF 30c via the ground gNB-CU 20-1a of the gNB-DU handover trigger, the source space-borne gNB-DU 20-21a sends one uplink (UL) RRC message transfer (UL RRC MESSAGE TRANSFER) message to the ground gNB-CU 20-1a. The uplink (UL) RRC message transfer message includes all the bearer contexts associated with the UE group indicating the space-borne access type change. The RRC signaling from the UE informs the ground gNB-CU 20-1a that the UE group has moved to the cell of the target space-borne gNB-DU 20-22a. The cell can be referred to as the target cell.

[0105] The ground gNB-CU 20-1a sends a per-UE group context setup request (CONTEXT SETUP REQUEST) message to the target space-borne gNB-DU 20-22a to create the bearer contexts associated with the UE group indicating the space-borne access type change and to establish the related data bearers for the UE group. An example of the per-UE group context setup request (CONTEXT SETUP REQUEST) message is shown in Table 6.

[0106] The target space-borne gNB-DU 20-22a responds to the ground gNB-CU 20-1a with a single per-UE group context setup response message for the UE group indicating the space-borne access type change.

[0107] ​The ground gNB-CU 20-1a sends a per-UE group context setup request (CONTEXT SETUP REQUEST) message to the source on-board gNB-DU 20-21a. The per-UE group context setup request (CONTEXT SETUP REQUEST) message includes a per-UE group RRC reconfiguration message scrambled with a group-based radio network temporary identifier (RNTI). The per-UE group RRC reconfiguration message is used to indicate when to stop data transmission for the UE group indicating an on-board access type change and to provide access-related configuration information for the target on-board gNB-DU 20-22a. For example, the access-related configuration information for the target on-board gNB-DU 20-22a includes one or more of the following: target gNB-DU ID, cell ID, new group-based RNTI, target gNB security algorithm identifier for selected security algorithms, and / or dedicated random access channel (RACH) resources, association between RACH resources and synchronization signal blocks (SSBs), association between RACH resources and UE-specific channel state information-reference signal (CSI-RS) configurations, common RACH resources, and system information for the target cell, etc. The source on-board gNB-DU 20-21a also sends a downlink data delivery status frame to inform the ground gNB-CU 20-1a of any unsuccessfully delivered downlink data to the UE group.

[0108] The source on-board gNB-DU 20-21a forwards the received per-UE group scrambled RRC reconfiguration message to the UE group according to its indication of on-board access type change and responds to the ground gNB-CU 20-1a with a per-UE group context modification response (CONTEXT MODIFICATION RESPONSE) message. Each UE within the group can then individually perform a random access procedure to access the target on-board gNB-DU 20-22a. The target on-board gNB-DU 20-22a sends a downlink data delivery status frame to inform the ground gNB-CU 20-1a. Downlink packets in the source on-board gNB-DU 20-21a, which can include packet data convergence protocol (PDCP) protocol data units (PDUs) that were unsuccessfully transmitted to the UE group, are sent by the ground gNB-CU 20-1a to the target on-board gNB-DU 20-22a. The UEs in the UE group individually respond to the target on-board gNB-DU 20-22a with an RRC reconfiguration complete message.

[0109] The target on-board gNB-DU 20-22a sends an UL RRC MESSAGE TRANSFER message to the ground gNB-CU 20-la to transfer the received RRC reconfiguration complete message. Packets in downlink and uplink direction are sent to or received from the UE group indicating the on-board access type change. In addition, uplink packets are sent from the UEs which are forwarded by the target on-board gNB-DU 20-22a to the ground gNB-CU 20-la.

[0110] The ground gNB-CU 20-la sends a release UE group context per command message to the source on-board gNB-DU 20-21a to release the UE group indicating the on-board access type change.

[0111] The source on-board gNB-DU 20-21a releases the bearer context associated with the UE group indicating the on-board access type change and responds to the ground gNB-CU 20-la with a release UE group context complete message.

[0112] Table 6

[0113] Full on-board radio access node: Embodiments of the present disclosure can be applied to scenarios where the radio access node is fully deployed on-board a satellite. For example, a gNB or functionally split gNB (gNB-CU and gNB-DU) functions are deployed on-board a satellite and connected through multiple NG-C and NG-U interfaces to ground network nodes performing control plane functions (e.g. Access and Management Function (AMF), Session Management Function (SMF) and / or User Plane Function (UPF)) respectively. The gNB / gNB-CU are connected to each other through Xn / X2 interfaces. In this particular scenario, when the satellite constellation moves, the gNB also needs to relocate from its associated UPF 30b. This results in frequent updates of the NG-U tunnels per individual UE connection, modification of PDU / multicast / broadcast sessions and potential signaling of gNB-DU handover.

[0114] To solve this problem, the AMF 30c or the source on-board gNB can group the UEs based on the information within the indication message, the coverage group type and / or other relevant information from the UE group and implement a release UE group context per NG-U tunnel update procedure, modification of PDU / multicast / broadcast sessions and / or gNB-CU handover signaling.

[0115] As Figure 7 shown in the example of FIG. 1, UEs 10a-10c are divided into group 1. UEs 10d-10e are divided into group 2. UEs 10f-10g are divided into group 3.

[0116] Referring to Figure 8 , signaling between entities in the network system is detailed below. Examples of UEs 10 can include UEs 10a-10g.

[0117] The UE is configured by the first space-borne radio access node 201 (e.g., old / source space-borne radio access node) to send RRC signaling to report one or more of the following instances: • Measurements of one or both of the first space-borne radio access node 201 and the second space-borne radio access node 202; • Indication of the Physical Cell Identity (PCI) of one or both of the first space-borne radio access node 201 and the second space-borne radio access node 202; and • Indication that the UE’s current serving space-borne radio access node has changed.

[0118] The UE located in the overlapping area between the first space-borne radio access node 201 and the second space-borne radio access node 202 or the UE capable of receiving a new satellite related System Information Block (SIB) can generate the report. An example showing the PCI or the indication of the change of the current serving space-borne radio access node is provided in Table 7 below. The SIB change indication reported by the UE in group 2 indicates the change of the current serving space-borne radio access node by transmitting two PCIs, i.e., [PCI, PCI2].

[0119] Table 7

[0120] Optionally, the UE can decide to send Non-Access Stratum (NAS) signaling to the Access and Mobility Management Function (AMF) 30c based on preconfigured parameters from the network, e.g., UE location or satellite ephemeris data. For example, the NAS signaling conveys Protocol Data Unit (PDU), multicast or broadcast session’s join, modification or update, and indication of access type change of the UE group. Referring to TS 29.502, the access type change indicates that the access type of the PDU, multicast or broadcast session has changed, e.g., from non-3GPP access to 3GPP access or from 3GPP access to non-3GPP access. Table 8 below shows an example of explicit session access type change indication.

[0121] Table 8

[0122] Optionally, the AMF 30c can decide to send the handover trigger indication to the source on-board NG-RAN node based on non-access stratum (NAS) signaling from the UE or AMF 30c internal configuration (e.g., based on UE location information, satellite ephemeris, or an indication of a radio access technology (RAT) information type change for a UE group or UE session from the source on-board NG-RAN node as given in Option 1 or 2).

[0123] Option 1: As indicated by the RAT information, the UEs in Group 1 do not change the satellite access type, while the UEs in Group 2 and Group 3 change the satellite access type. The following Table 9 and Table 10 show examples of the indication of the RAT information type change.

[0124] Table 9

[0125] Option 2: As indicated by the RAT information, the UEs in Group 1 and Group 2 do not change the satellite access type, while the UEs in Group 3 change the satellite access type.

[0126] Table 10

[0127] Reference Figure 8 Upon receiving the signaling message indication from the UE, the first on-board wireless access node 201 and / or the ground network node divides the UEs into different UE groups based on the signaling message indication from the UEs. The signaling message indication from the UEs can be a radio resource control (RRC) configuration message. The first on-board wireless access node 201 can be a source on-board gNB 20a. The ground network node can be an access and mobility management function (AMF). As shown in the example of Figure 7 The UEs 10a-10c are divided into Group 1. The UEs 10d-10e are divided into Group 2. The UEs 10f-10g are divided into Group 3.

[0128] Initiation of the handover can be based on various handover trigger events, which can include one or more of the following: RRC signaling from the UE, internal configuration of the source on-board gNB 20a, indication of handover trigger from the AMF 30c, and handover required response (command) from the AMF 30c for PDUs and / or Multimedia Broadcast / Multicast Service (MBS) sessions associated with a group of UEs indicating on-board access type change. In response to the handover trigger event, the source on-board gNB 20a triggers a handover request to the target on-board gNB 20b node to initiate group-based resource setup, modification, release for PDUs and / or MBS sessions associated with a group of UEs indicating on-board access type change. One example of a per-UE group NG session resource setup signaling message is given in Table 11 below.

[0129] The target on-board gNB 20b can respond to the handover request from the source on-board gNB 20a by establishing, modifying, or requesting release of resources for PDU and / or MBS sessions contexts associated with the group of UEs indicated in the handover request provided from the source on-board gNB 20a. The target on-board gNB 20b can also trigger a N2 path switch request to the AMF 30c to inform the AMF 30c that the group of UEs has moved to the cell of the target on-board gNB 20b. The cell can be referred to as a target cell. The N2 path switch request can include a list of PDU / MBS sessions to be handed over for the group of UEs indicated in the handover request.

[0130] Based on the response from the target on-board gNB 20b, the source on-board gNB 20a triggers a Uu handover by sending a group-based Radio Resource Control (RRC) message scrambled with a group Radio Network Temporary Identifier (RNTI) to the group of User Equipment (UEs) indicated in the handover request, which contains information required to access the target on-board gNB 20b, such as target gNB cell ID, new C-RNTI, target gNB security algorithm identifier for selected security algorithms and / or dedicated Random Access Channel (RACH) resources, association between RACH resources and one or more Synchronization Signal Blocks (SSBs), association between RACH resources and one or more UE-specific Channel State Information (CSI)-Reference Signals (RSs), common RACH resources, and system information of the target cell, etc.

[0131] The Access and Mobility Management Function (AMF) 30c sends an Update SM Context Request to the Session Management Function (SMF) 30d to request the SMF 30d to update the Session Management (SM) context for the respective Protocol Data Unit (PDU) / Multimedia Broadcast / Multicast Service (MBS) sessions of the UE group. The Update SM Context Request can include a list of PDU / MBS sessions related to the UE group indicated in the N2 Path Switch Request. For the list of PDU / MBS sessions related to the UE group indicated in the N2 Path Switch Request, the SMF 30d sends an N4 Session Modification Request message to the User Plane Function (UPF) 30b. The UPF 30b then switches the path of the PDU / MBS sessions related to the UE group indicated in the N2 Path Switch Request to the target on-boarding gNB 20b and returns an N4 Session Modification Response message to the SMF 30d indicating that the path of the PDU / MBS sessions related to the UE group indicated in the N2 Path Switch Request has been switched. The SMF 30d sends an Update SM Context Response to the AMF 30c over interface N11 indicating the PDU / MBS sessions related to the UE group that have been successfully switched.

[0132] The AMF 30c sends an N2 Path Switch Request Ack to the target on-boarding gNB 20b indicating that the list of PDU / MBS sessions related to the UE group indicated in the N2 Path Switch Request has been successfully switched to the new N3 interface connecting the target on-boarding gNB 20b to the core network.

[0133] Based on the Path Switch Request Ack from the AMF 30c, the target on-boarding gNB 20b confirms the success of the switch by sending a request to the source on-boarding gNB 20a to release the resources associated with the PDU / MBS sessions related to the UE group that have been successfully switched.

[0134] The definition of the signaling messages for the per-UE group NG session is shown in the following table.

[0135] Table 11

[0136] Table 12

[0137] Table 13

[0138] Table 14

[0139] Table 15

[0140] The present disclosure provides a method of supporting satellite access with on-board radio access node functionality according to the requirements discussed for Release 19 satellite access. The beneficial and innovative aspects of the present disclosure include: (1). The present disclosure introduces new per-UE group session or context management and / or handover related signaling and procedures to handle the signaling overload problem in the F1-C and NG-C control plane interfaces.

[0141] (2). The present disclosure also introduces a new set of signaling and indications or triggers to assist in implementing per-UE group session or context management and handover signaling to handle the scenario where the access node is on-board.

[0142] Referring to Figure 9 , the user equipment UE 100 can include a processor 11a, a memory 12a, and a transceiver 13a. The processor 11a is configured to invoke and run a computer program stored in the memory 12a to cause the UE 10 in which the processor 11 is installed to perform the methods, steps, and / or functions of the disclosed UE. The UE 100 is an example of the UE 10 and the UE 10a-10g. The transceiver 13a can include baseband circuitry and radio frequency (RF) circuitry.

[0143] Referring to Figure 10 , the network node 200 is a network device, which can include a processor 21a, a memory 22a, and a transceiver 23a. The processor 21a is configured to invoke and run a computer program stored in the memory 22a to cause the user equipment UE 10 in which the processor 11 is installed to perform the methods, steps, and / or functions of the network node. The network node 20 is an example of the gNB 20a, the gNB-CU 20-1a, the gNB-DU 20-21a, the gNB-DU 20-22a, the on-board gNB 20b, the gNB-CU 20-1c, the gNB-DU 20-2c, the gNB 20d, the first on-board wireless access node 201, the second on-board wireless access node 202, the UPF 30b, the AMF 30c, and the SMF 30d. The transceiver 23a can include baseband circuitry and radio frequency (RF) circuitry.

[0144] Referring to Figure 11 , the embodiments of the present disclosure also provide a chip 700, which can correspond to the user equipment 10 in the embodiments of the present disclosure. The chip 700 can implement the corresponding processes implemented by the user equipment 10 in various methods of the embodiments of the present disclosure. The chip 700 includes a processor 701, which can invoke and run a computer program from a memory to implement the methods in the embodiments of the present disclosure.

[0145] Optionally, the chip 700 can further include a memory 702. Specifically, the processor 701 can invoke and run a computer program from the memory 702 to implement the methods in the embodiments of the present application.

[0146] In addition, the memory 702 can be a device separate from the processor 701, or can be integrated into the processor 701.

[0147] Optionally, the chip 700 can further include an input interface 703. It should be noted that the processor 701 can control the input interface 703 to communicate with other devices or chips, specifically for obtaining messages or data sent by other devices or chips.

[0148] Optionally, the chip 700 can further include an output interface 704. It should be noted that the processor 701 can control the output interface 704 to communicate with other devices or chips, specifically for outputting messages or data to other devices or chips.

[0149] Referring to Figure 12 , the embodiments of the present disclosure also provide another chip 800, which can correspond to the gNB 20 in the embodiments of the present disclosure. The chip 800 can implement the corresponding processes implemented by the gNB 20 in various methods of the embodiments of the present disclosure. The chip 800 includes a processor 801, which can invoke and run a computer program from a memory 802 to implement the methods in the embodiments of the present application.

[0150] Optionally, the chip 800 can further include a memory 802. Specifically, the processor 801 can invoke and run a computer program from the memory 802 to implement the methods in the embodiments of the present application.

[0151] The memory 802 can be a device separate from the processor 801, or can be integrated into the processor 801.

[0152] Optionally, the chip 800 can further include an input interface 803. Specifically, the processor 801 can control the input interface 803 to communicate with other devices or chips, specifically for obtaining messages or data sent by other devices or chips.

[0153] Optionally, the chip can further include an output interface 804. Specifically, the processor 801 can control the output interface 804 to communicate with other devices or chips, specifically for outputting messages or data to other devices or chips.

[0154] It should be understood that the processor in the embodiments of the present application can be an integrated circuit chip having a signal processing capability. In the implementation process, the steps of the method embodiments described above can be completed by an integrated logic circuit in hardware form or an instruction in software form in the processor. The processor can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components. The various methods, steps and logical block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general purpose processor can be a microprocessor, or the processor can also be any conventional processor or the like. The steps of the method disclosed in the embodiments of the present application can be directly embodied and executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in a random access memory, a flash memory, a read only memory, a programmable read only memory or an electrically erasable programmable memory, a register, and other storage medium known in the art. The storage medium is located in the memory, and the processor reads the information in the memory and combines the hardware to implement the steps of the above method.

[0155] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or can include both volatile memory and non-volatile memory. Among them, the non-volatile memory can be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electrically Erasable Programmable Read-Only Memory (EEPROM) or a flash memory. The volatile memory can be a Random Access Memory (RAM) used as an external cache. For example, but not limited to, there are various forms of RAM available, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRAM), Double Data Rate SDRAM (DDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), Synchlink DRAM (SLDRAM) and Direct Rambus RAM (DR RAM). It should be noted that the memory of the system and method described herein is intended to include but not limited to these and any other suitable memory types.

[0156] The embodiments of the present application also provide a computer program product comprising computer program instructions.

[0157] Alternatively, the computer program product can be applied to the network node in the embodiments of the present application, and the computer program instructions make the computer execute the corresponding processes realized by the network node in various methods of the embodiments of the present application, which will not be described here for brevity.

[0158] Optionally, the computer program product can be applied to the user equipment (UE) in the embodiments of the present application, and the computer program instructions cause the computer to perform the corresponding processes implemented by the user equipment (UE) in various methods of the embodiments of the present application. For brevity, details are not repeated here.

[0159] Embodiments of the present disclosure also provide a computer program.

[0160] Optionally, the computer program can be applied to the network node in the embodiments of the present application, and when the computer program runs on the computer, the computer executes the corresponding processes implemented by the network node in various methods of the embodiments of the present application. For brevity, details are not repeated here.

[0161] Optionally, the computer program can be applied to the user equipment (UE) in the embodiments of the present application, and when the computer program runs on the computer, the computer executes the corresponding processes implemented by the user equipment (UE) in various methods of the embodiments of the present application. For brevity, details are not repeated here.

[0162] Those of ordinary skill in the art can appreciate that the units and algorithm steps described in conjunction with various examples of the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0163] Those skilled in the art can understand that, for the convenience and brevity of description, the specific working process of the above system, device and unit can refer to the corresponding process in the foregoing method embodiments, and details are not repeated here.

[0164] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the above-mentioned device embodiments are only schematic, for example, the division of the units is only a logical function division, and in actual implementation, other division manners can be adopted, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0165] The units illustrated as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., they can be located in one place, or can also be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present application.

[0166] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be physically present alone, or two or more units can be integrated into one unit.

[0167] If the function is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, all or part of the technical solutions of the present application can be embodied in the form of a software product, which embodies the essence or contribution of the present technical solution to the prior art, and is stored in a storage medium, and includes several instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. All or part of the steps of the embodiments of the present application. The storage medium mentioned above is a non-volatile storage medium, including a portable disk, a removable hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, etc. Various media that can store program codes.

[0168] The present disclosure provides a method for supporting satellite access with on-board radio access node functionality. The benefits and innovative aspects of the present disclosure include: The present disclosure introduces new signaling and procedures related to per-UE group session or context management and handover. These enhancements aim to mitigate the signaling overload issue within the F1-C and NG-C control plane interfaces.

[0169] The present disclosure also introduces a new set of signaling, indications, and triggers aimed at enabling per-UE group session or context management and handover signaling, especially in scenarios where the access node is located on a satellite.

[0170] Although the present disclosure has been described in conjunction with the embodiments considered to be the most practical and preferred, it should be understood that the present disclosure is not limited to the disclosed embodiments, but is intended to cover various arrangements made without departing from the scope of the appended claims under the broadest interpretation.

Claims

1. A satellite access method, comprising: a user equipment, UE, sending a signaling message indication to a first spaceborne wireless access node and / or a ground network node, wherein the signaling message indication indicates a change of a currently serving spaceborne wireless access node; the first spaceborne wireless access node and / or the ground network node dividing the UE into different UE groups based on the signaling message indication from the UE; and the first spaceborne wireless access node and / or the ground network node triggering a handover of the at least one UE group from the first spaceborne wireless access node to a second spaceborne wireless access node, wherein the handover of the at least one UE group is based on the signaling message indication from the UE and / or a per-UE group signaling message provided by the first spaceborne wireless access node and / or the ground network node.

2. The satellite access method of claim 1, further comprising: the ground network node, the first spaceborne wireless access node, and / or the second spaceborne wireless access node initiating a per-UE group establishment, addition, modification, and / or release of bearer context and / or session resources associated with the at least one UE group.

3. The satellite access method of claim 1, further comprising: the first spaceborne wireless access node sending a per-UE group handover signaling to the at least one UE group, the handover signaling indicating a handover to the second spaceborne wireless access node.

4. The satellite access method of any one of claims 1 to 3, wherein, the ground network node is an access and mobility management function, AMF, and / or a centralized unit of a base station, gNB-CU.

5. The satellite access method of any one of claims 1 to 3, wherein, the per-UE group signaling message is a message sent from a spaceborne wireless access node to the ground network node.

6. The satellite access method of any one of claims 1 to 3, wherein, the signaling message indication from the UE is a non-access stratum, NAS, message sent from the UE to the ground network node, wherein the signaling message indication is a preconfigured parameter including a UE location or satellite ephemeris data.

7. The satellite access method of any one of claims 1 to 3, wherein, the signaling message indication from the UE is a radio resource control, RRC, configuration message.

8. The satellite access method of claim 7, wherein, the signaling message indication and / or the per-UE group signaling message includes at least one of the following: a coverage group type change, a reference location change, a reference time change, a coverage and / or measurement change, a frequency change, a physical cell identity change, a satellite access related SIB change, a satellite ID change, a UE session access type change, and / or other associated information.

9. The satellite access method of claim 7, wherein, the signaling message indication and / or the per-UE group signaling message includes one or more of the following: a measurement of one or both of the first and second spaceborne wireless access nodes; an indication of a physical cell identity, PCI, of one or both of the first and second spaceborne wireless access nodes; and an indication that a currently serving spaceborne wireless access node of the UE has changed.

10. The satellite access method of claim 6, wherein, the NAS message conveys an indication of a protocol data unit, PDU, session, a join, a modification, or an update of a multicast or broadcast session, and an access type change of the at least one UE group.

11. The satellite access method of claim 1, wherein, a session associated with the at least one UE group includes a protocol data unit, PDU, session or a multimedia broadcast / multicast service, MBS, session.

12. The satellite access method of claim 1, further comprising: The first satellite-based wireless access node transmits a group-based radio resource control, RRC, message scrambled with a group radio network temporary identifier, RNTI, to the at least one UE group.

13. The satellite access method of claim 12, wherein, The group-based RRC message comprises a per-UE group RRC reconfiguration message scrambled with a group-based RNTI to indicate when to stop data transmission for the at least one UE group that has indicated an on-board access type change, and / or to provide access related configuration information of the second satellite-based wireless access node.

14. The satellite access method of claim 1, further comprising: The second satellite-based wireless access node transmits a path switch request to the ground network node to request a path switch of a bearer context or session for the at least one UE group.

15. The satellite access method of claim 1, wherein, The first satellite-based wireless access node comprises a first on-board distributed unit of a base station; The second satellite-based wireless access node comprises a second on-board distributed unit of the base station; and The ground network node comprises a ground centralized unit of the base station.

16. The satellite access method of claim 15, wherein, The first on-board distributed unit transmits a single uplink, UL, RRC message transfer message to the ground centralized unit of the base station, the UL RRC message transfer message comprising all bearer contexts associated with the at least one UE group that indicates an on-board access type change.

17. The satellite access method of claim 16, wherein, The ground centralized unit of the base station transmits a per-UE group context setup request message to the second on-board distributed unit of the base station to create bearer contexts associated with the at least one UE group that indicates the on-board access type change and to establish related data bearers for the at least one UE group; and The second on-board distributed unit of the base station responds to the ground centralized unit of the base station with a per-UE group context setup response message.

18. The satellite access method of claim 17, wherein, The ground centralized unit of the base station transmits a per-UE group context modification request message to the first on-board distributed unit; The per-UE group context modification request message comprises a per-UE group RRC reconfiguration message scrambled with a group-based RNTI; The per-UE group RRC reconfiguration message is used to indicate when to stop data transmission for the at least one UE group that indicates the on-board access type change, and / or to provide access related configuration information of the second on-board distributed unit of the base station; and The first on-board distributed unit forwards the received per-UE group scrambled RRC reconfiguration message to the at least one UE group according to the indication of the on-board access type change of the at least one UE group and responds to the ground centralized unit of the base station with a per-UE group context modification response message.

19. The satellite access method of claim 18, wherein, The access-related configuration information of the second on-board distributed unit of the base station comprises one or more of the following: a distributed unit gNB-DU ID of the second base station, a cell ID, a new group-based RNTI, a second gNB security algorithm identifier for a selected security algorithm, and / or random access channel RACH resources, an association between RACH resources and one or more synchronization signal blocks SSBs, an association between RACH resources and one or more UE-specific channel state information CSI-reference signal RS configurations, common RACH resources, and / or system information of the second cell.

20. The satellite access method of claim 18, wherein, The UEs in the at least one UE group respond to the second on-board distributed unit of the base station with an RRC reconfiguration complete message; and The second on-board distributed unit of the base station sends an UL RRC message transfer message to the ground centralized unit of the base station to convey the received RRC reconfiguration complete message.

21. The satellite access method of claim 20, wherein, The ground centralized unit of the base station sends a per-UE group context release command message to the first on-board distributed unit to release the at least one UE group indicating the on-board access type change; and The first on-board distributed unit releases the bearer context associated with the at least one UE group indicating the on-board access type change and responds to the ground centralized unit of the base station with a UE context release complete message.

22. The satellite access method of claim 1, wherein, The first space-borne wireless access node comprises a first on-board base station; The second space-borne wireless access node comprises a second on-board base station; and The ground network node comprises an access and mobility management function AMF.

23. The satellite access method of claim 22, wherein, The first on-board base station triggers a handover request to the second on-board base station node to initiate a group-based establishment, modification, release of resources for PDU and / or MBS sessions associated with the at least one UE group indicating an on-board access type change; The second on-board base station responds to the handover request from the first on-board base station by establishing, modifying, or requesting to release resources for PDU and / or MBS session contexts associated with the at least one UE group indicated in the handover request provided from the first on-board base station; and Based on the response from the second on-board base station, the first on-board base station triggers a Uu handover by sending a group RRC message scrambled with a group RNTI to the at least one UE group indicating the handover request.

24. The satellite access method of claim 23, wherein, The second on-board base station triggers an N2 path switch request to the AMF to inform the AMF that the at least one UE group has moved to a cell of the second on-board base station, the N2 path switch request comprising a list of packet data unit PDU / multicast / broadcast service MBS sessions of the at least one UE group switching indicating the handover request.

25. The satellite access method of claim 23, wherein, The scrambled group-based RRC message comprises one or more of the following: a second gNB cell ID, a new C-RNTI cell-RNTI, a second gNB security algorithm identifier for a selected security algorithm, and / or dedicated random access channel, RACH, resources, an association between RACH resources and one or more synchronization signal blocks, SSBs, an association between RACH resources and one or more UE-specific channel state information, CSI, reference signal, RS, configurations, common RACH resources, and / or system information of the second cell.

26. The satellite access method of claim 23, wherein, The AMF sends an update session management, SM, context request to a session management function, SMF, to request the SMF to update SM contexts for respective PDU / MBS sessions of the at least one UE group; the update SM context request comprises a list of PDU / MBS sessions related to the at least one UE group indicated in the N2 path switch request; for the list of PDU / MBS sessions related to the at least one UE group indicated in the N2 path switch request, the SMF sends an N4 session modification request message to a user plane function, UPF; the UPF switches paths of PDU / MBS sessions related to the at least one UE group indicated in the N2 path switch request to the second satellite base station and returns an N4 session modification response message to the SMF, the N4 session modification response message indicating that the paths of PDU / MBS sessions related to the at least one UE group indicated in the N2 path switch request are switched; and the SMF sends an update SM context response to the AMF, the update SM context response indicating PDU / MBS sessions related to the at least one UE group that have been successfully switched.

27. The satellite access method of claim 26, wherein, the AMF sends a path switch request acknowledgement to the second satellite base station, the path switch request acknowledgement indicating that the list of PDU / MBS sessions related to the at least one UE group indicated in the N2 path switch request have been successfully switched to a new N3 interface connecting the second satellite base station to a core network; and based on the path switch request acknowledgement from the AMF, the second satellite base station confirms the success of the switch by sending a request to the first satellite base station for releasing resources of PDU / MBS sessions associated with the at least one UE group that have been successfully switched.

28. A system comprising: a user equipment, UE; a first satellite-based wireless access node; and a ground network node; wherein the user equipment, UE, is configured to send a signaling message indication to the first satellite-based wireless access node and / or the ground network node, wherein the signaling message indication indicates a change of a currently serving satellite-based wireless access node; the first satellite-based wireless access node and / or the ground network node is configured to divide the UE into different UE groups based on the signaling message indication from the UE; the first space-borne wireless access node and / or the ground network node is configured to trigger a handover of the at least one UE group from the first space-borne wireless access node to a second space-borne wireless access node; and the handover of the at least one UE group is based on the signaling message indication from the UE and / or a per-UE group signaling message provided by the first space-borne wireless access node and / or the ground network node.

29. The system of claim 28, wherein, the first space-borne wireless access node comprises a base station; and the ground network node is an access and mobility management function, AMF.

30. The system of claim 28, wherein, the first space-borne wireless access node comprises a first space-distributed unit of a base station; the second space-borne wireless access node comprises a second space-distributed unit of the base station; and the ground network node comprises a ground-centralized unit of the base station.

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