Methods and apparatuses for authentication for store and forward user equipment registration

Abstract

Techniques for authenticating a user equipment to a network are provided. For example, a method performed by a non-terrestrial node in a network, comprises: receiving, from a user equipment, a registration request to authenticate to the network; responsive to a link between the non-terrestrial node and a terrestrial node of the network to forward the registration request not being available: storing the registration request, and assigning binding information associated with the non-terrestrial node to the user equipment; and transmitting, to the user equipment, a message comprising the binding information to be used by the user equipment.

Description

METHODS AND APPARATUSES FOR AUTHENTICATION FOR STORE AND FORWARD USER EQUIPMENT REGISTRATIONTECHNICAL FIELD

[0001] Various example embodiments generally relate to a wireless communication technique. More specifically, measures / mechanisms (including methods, apparatuses, and computer program products) are described for authenticating user equipment and Internet-of- Things devices.BACKGROUND

[0002] Various example embodiments relate to considerations in a (e.g., mobile / wireless) communication system or network, such as a 5G / NR system and a next-generation system beyond 5G. For example, various example embodiments are applicable in a 3GPP- standardized mobile / wireless communication system or network of Release 18 onwards.

[0003] The feasibility of using 5G NR standards to support non-terrestrial networks (NTN) has been studied for Releases 15 and 16 of the 3GPP-standardized mobile / wireless communication system or network. In an NTN system, 5G base stations (gNBs) may be deployed on board of satellites and / or satellites may act as a kind of relay for ground-based gNBs to provide communication coverage over a very large area that may be otherwise unreachable by cellular networks. Such functionality can be used to connect user equipment (UEs) or Internet-of-Things (loT) devices globally as well as provide personal communication in remote areas and in disaster relief.

[0004] An example NTN scenario is illustrated in FIG. 4. According to this NTN scenario, UEs are provided with services of a data network via a service link from a satellite or an unmanned aerial system (UAS) platform. The satellite or UAS platform provides communication coverage over a very large area, for example, in the form of a plurality of smaller areas (shown as beam footprint). The satellite or UAS platform is communicating with the data network via a feeder link over a gateway.

[0005] In such NTN scenario, either the service link or the feeder link may be not available due to mobility of the satellite or UAS platform or the mobility of the UE. In such situations, UE registration procedure may not be executed successfully.

[0006] Accordingly, there is a demand for a UE registration procedure that allows to authenticate the UE to the data network even in cases the service link or the feeder link are not available, at least temporarily.LIST OF ACRONYMS AND ABBREVIATIONS

[0007] The following acronyms and abbreviations are used throughout the subject disclosure:3GPP 3rd Generation Partnership ProgramAMF Access and Mobility Management FunctionAS Access StratumCN Core NetworkGW GatewayID Identifier loT Internet of ThingsISL Inter Satellite LinkMO Mobile OrientedMT Mobile TerminatedNAS Non-Access StratumNGAP Next Generation Application ProtocolPDU Processing Data UnitRAN Radio Access NetworkRNTI Radio Network Temporary IdentifierRRC Radio Resource ControlSAT SatelliteSUCI Subscription Concealed IdentifierS&F Store and ForwardUE User EquipmentSUMMARY

[0008] It is an object of the subject disclosure to provide mechanisms for authenticating user equipment to a network. There are provided methods and apparatuses for authenticating user equipment to a network.

[0009] According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims.

[0010] According to a first aspect of the subject disclosure, there is provided a method performed by a terminal node in a network. Examples of the terminal node may comprise a User Equipment (UE) and an Internet-Of-Things (loT) device. The method comprises: transmitting, to a non-terrestrial node (e.g., a non-terrestrial network node or a non-terrestrial base station), a registration request; and receiving, from the non-terrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the terminal node, the binding information being assigned to the terminal node. For example, theregistration request may comprise a registration request to authenticate the terminal node to the network.

[0011] In some examples of the first aspect, the method may further comprise storing the binding information for use by the terminal node; and receiving, from the non-terrestrial node, one or more further messages comprising the binding information as an identifier of the terminal node (i.e., instead of an User Equipment (UE) identifier).

[0012] In some examples of the first aspect, the registration request may comprise an identifier associated with the terminal node. In some examples, the identifier may comprise a Subscription Concealed Identifier (SUCI) of the terminal node.

[0013] In some examples of the first aspect, the method may further comprise performing a procedure to establish a connection to the non-terrestrial node. In some examples, the connection may comprise a Radio Resource Control (RRC) connection between the terminal node and the non-terrestrial node.

[0014] In some examples of the first aspect, the method may further comprise receiving, from the non-terrestrial node, a paging message using the binding information.

[0015] In some examples of the first aspect, the method may further comprise: receiving, from the non-terrestrial node, an Authentication and Key Agreement (AKA) challenge; transmitting, to the non-terrestrial node, a response to the AKA challenge; and authenticating the terminal node to the network. For example, the AKA challenge may comprise an AKA challenge to authenticate the terminal node.

[0016] In some examples of the first aspect, the method may further comprise: responsive to a link (e.g., the service link) between the terminal node and the non-terrestrial node available via another non-terrestrial node acting as a relay node, receiving, from the non-terrestrial node via the other non-terrestrial node, a paging message using the binding information.

[0017] In some examples of the first aspect, the method may further comprise: receiving, from the non-terrestrial node via the other non-terrestrial node, the AKA challenge; transmitting, to the non-terrestrial node via the other non-terrestrial node, a response to the AKA challenge; and authenticating the terminal node to the network.

[0018] In some examples of the first aspect, the binding information may be used by the terminal node until the terminal node is authenticated to the network.

[0019] In some examples of the first aspect, the binding information may comprise Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

[0020] According to a second aspect of the subject disclosure, a terminal node (e.g., a user device, User Equipment (UE) or Internet-of-Things (loT) device) or an apparatus in such a terminal node is provided. The terminal node or apparatus according to the second aspect comprises at least one processor and at least one memory storing instructions. The instructions cause the terminal node or apparatus, when executed with the at least one processor, to: transmit, to a non-terrestrial node (e.g., a non-terrestrial network node or a non-terrestrial basestation), a registration request; and receive, from the non-terrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the terminal node, the binding information being assigned to the terminal node. For example, the registration request may comprise a registration request to authenticate the terminal node to the network.

[0021] In some examples of the second aspect, the instructions may further cause the terminal node or apparatus, when executed with the at least one processor, to store the binding information for use by the terminal node; and receive, from the non-terrestrial node, one or more further messages comprising the binding information as an identifier of the terminal node (i.e., instead of an User Equipment (UE) identifier).

[0022] In some examples of the second aspect, the registration request may comprise an identifier associated with the terminal node. In some examples, the identifier comprises a Subscription Concealed Identifier (SUCI) of the terminal node.

[0023] In some examples of the second aspect, the instructions may further cause the terminal node or apparatus, when executed with the at least one processor, to perform a procedure to establish a connection to the non-terrestrial node. In some examples, the connection may comprise a Radio Resource Control (RRC) connection between the terminal node and the non-terrestrial node.

[0024] In some examples of the second aspect, the instructions may further cause the terminal node or apparatus, when executed with the at least one processor, to receive, from the non-terrestrial node, a paging message using the binding information.

[0025] In some examples of the second aspect, the instructions may further cause the terminal node or apparatus, when executed with the at least one processor, to: receive, from the non-terrestrial node, an Authentication and Key Agreement (AKA) challenge; transmit, to the non-terrestrial node, a response to the AKA challenge; and authenticate the terminal node to the network. For example, the AKA challenge may comprise an AKA challenge to authenticate the terminal node.

[0026] In some examples of the second aspect, the instructions may further cause the terminal node or apparatus, when executed with the at least one processor, to: responsive to a link (e.g., a service link) between the terminal node and the non-terrestrial node available via another non-terrestrial node acting as a relay node, receive, from the non-terrestrial node via the other non-terrestrial node, a paging message using the binding information.

[0027] In some examples of the second aspect, the instructions may further cause the terminal node or apparatus, when executed with the at least one processor, to: receive, from the non-terrestrial node via the other non-terrestrial node, the AKA challenge; transmit, to the nonterrestrial node via the other non-terrestrial node, a response to the AKA challenge; and authenticate the terminal node to the network.

[0028] In some examples of the second aspect, the binding information may be used by the terminal node until the terminal node is authenticated to the network.

[0029] In some examples of the second aspect, the binding information may comprise Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

[0030] According to a third aspect of the subject disclosure, a terminal node (e.g., a user device, User Equipment (UE) or Internet-of-Things (loT) device) or an apparatus in such a terminal node is provided. The terminal node or apparatus according to the third aspect comprises: means or modules for transmitting, to a non-terrestrial node (a non-terrestrial network node or non-terrestrial base station), a registration request (e.g., a transmitter); and means or modules for receiving, from the non-terrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the terminal node, the binding information being assigned to the terminal node (e.g., a receiver). For example, the registration request may comprise a registration request to authenticate the terminal node to the network.

[0031] In some examples of the third aspect, the terminal node or apparatus further comprises means or modules for performing one or more of the examples according to the first aspect.

[0032] According to a fourth aspect of the subject disclosure, a terminal node (e.g., a user device, User Equipment (UE) or Internet-of-Things (loT) device) or an apparatus in such a terminal node is provided. The terminal node or apparatus according to the fourth aspect comprises: circuitry to transmit, to a non-terrestrial node (a non-terrestrial network node or non-terrestrial base station), a registration request; and circuitry to receive, from the nonterrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the terminal node, the binding information being assigned to the terminal node. For example, the registration request may comprise a registration request to authenticate the terminal node to the network.

[0033] In some examples of the fourth aspect, the terminal node or apparatus further comprises circuitry to perform one or more of the examples according to the first aspect.

[0034] According to a fifth aspect of the subject disclosure, there is provided a method performed by a non-terrestrial node in a network. Examples of the non-terrestrial node may comprise a non-terrestrial network node or non-terrestrial base station. The method comprises: receiving, from a terminal node (e.g., a user device, User Equipment (UE) or Internet-of-Things (loT) device), a registration request; responsive to a link (e.g., a feeder link) between the nonterrestrial node and a terrestrial node (e.g., a terrestrial network node, a terrestrial base station or a terrestrial gateway) of the network to forward the registration request not being available: storing the registration request; and assigning binding information associated with the nonterrestrial node to the terminal node; and transmitting, to the terminal node, a message comprising the binding information to be used by the terminal node. For example, the registration request may comprise a registration request to authenticate the terminal node to the network.

[0035] In some examples of the first aspect, the method may further comprise transmitting, to the terminal node, one or more further messages comprising the binding information as an identifier of the terminal node (i.e., instead of an User Equipment (UE) identifier).

[0036] In some examples of the fifth aspect, the registration request comprises an identifier associated with the terminal node. In some examples, the identifier may comprise a Subscription Concealed Identifier (SUCI) of the terminal node.

[0037] In some examples of the fifth aspect, the method may further comprise performing a procedure to establish a connection to the terminal node. In some examples, the connection may comprise a Radio Resource Control (RRC) connection between the terminal node and the non-terrestrial node.

[0038] In some examples of the fifth aspect, the method may further comprise: responsive to the link being available, forwarding the registration request to the terrestrial node to authenticate the terminal node to the network; receiving, from the terrestrial node, an Authentication and Key Agreement (AKA) challenge; and storing an association of the AKA challenge and the binding information. In some examples, the association of the AKA challenge and the binding information may be stored in a mapping table. For example, the AKA challenge may comprise an AKA challenge to authenticate the terminal node.

[0039] In some examples of the fifth aspect, the method may further comprise transmitting, to the terminal node, a paging message using the binding information.

[0040] In some examples of the fifth aspect, the method may further comprise: transmitting, to the terminal node, the AKA challenge; receiving, from the terminal node, a response to the AKA challenge; and authenticating the terminal node to the network.

[0041] In some examples of the fifth aspect, the method may further comprise: responsive to a link (e.g., a service link) between the terminal node and the non-terrestrial node available via another non-terrestrial node acting as a relay node, transmitting, to the terminal node via the other non-terrestrial node, a paging message using the binding information.

[0042] In some examples of the fifth aspect, the method may further comprise: transmitting, to the terminal node via the other non-terrestrial node, the AKA challenge; receiving, from the terminal node via the other non-terrestrial node, a response to the AKA challenge; and authenticating the terminal node to the network.

[0043] In some examples of the fifth aspect, the binding information may be used by the terminal node until the terminal node is authenticated to the network.

[0044] In some examples of the fifth aspect, the binding information may comprise Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

[0045] In some examples of the fifth aspect, the non-terrestrial node may be incorporated in, or associated with, a satellite.

[0046] According to a sixth aspect of the subject disclosure, a non-terrestrial node (e.g., a non-terrestrial network node or a non- terrestrial Base Station (BS)) in a network or an apparatus in such a non-terrestrial node is provided. The non-terrestrial node or apparatus according to the sixth aspect comprises at least one processor and at least one memory storing instructions. The instructions cause the non-terrestrial node or apparatus, when executed with the at least one processor, to: receive, from a terminal node (e.g., a user device, User Equipment (UE) or Internet-of-Things (loT) device), a registration request; responsive to a link (e.g. a feeder link) between the non-terrestrial node and a terrestrial node (e.g., a terrestrial network node, a terrestrial Base Station (BS) or a terrestrial gateway) of the network to forward the registration request not being available: store the registration request; and assign binding information associated with the non-terrestrial node to the terminal node; and transmit, to the terminal node, a message comprising the binding information to be used by the terminal node. For example, the registration request may comprise a registration request to authenticate the terminal node to the network.

[0047] In some examples of the second aspect, the instructions may further cause the nonterrestrial node or apparatus, when executed with the at least one processor, to transmit, to the terminal node, one or more further messages comprising the binding information as an identifier of the terminal node (i.e., instead of an User Equipment (UE) identifier).

[0048] In some examples of the sixth aspect, the registration request may comprise an identifier associated with the terminal node. In some examples, the identifier may comprise a Subscription Concealed Identifier (SUCI) of the terminal node.

[0049] In some examples of the sixth aspect, the instructions may further cause the nonterrestrial node or apparatus, when executed with the at least one processor, to perform a procedure to establish a connection to the terminal node. In some examples, the connection may comprise a Radio Resource Control (RRC) connection between the terminal node and the non-terrestrial node.

[0050] In some examples of the sixth aspect, the instructions may further cause the nonterrestrial node or apparatus, when executed with the at least one processor, to: responsive to the link being available, forward the registration request to the terrestrial node to authenticate the terminal node to the network; receive, from the terrestrial node, an Authentication and Key Agreement (AKA) challenge; and store an association of the AKA challenge and the binding information. In some examples, the association of the AKA challenge and the binding information may be stored in a mapping table. For example, the AKA challenge may comprise an AKA challenge to authenticate the terminal node.

[0051] In some examples of the sixth aspect, the instructions may further cause the nonterrestrial node or apparatus, when executed with the at least one processor, to transmit, to the terminal node, a paging message using the binding information.

[0052] In some examples of the sixth aspect, the instructions may further cause the nonterrestrial node or apparatus, when executed with the at least one processor, to: transmit, to the terminal node, the AKA challenge; receive, from the terminal node, a response to the AKA challenge; and authenticate the terminal node to the network.

[0053] In some examples of the sixth aspect, the instructions may further cause the nonterrestrial node or apparatus, when executed with the at least one processor, to: responsive to a link (e.g. a service link) between the terminal node and the non-terrestrial node available via another non-terrestrial node acting as a relay node, transmit, to the terminal node via the other non-terrestrial node, a paging message using the binding information.

[0054] In some examples of the sixth aspect, the instructions may further cause the nonterrestrial node or apparatus, when executed with the at least one processor, to: transmit, to the terminal node via the other non-terrestrial node, the AKA challenge; receive, from the terminal node via the other non-terrestrial node, a response to the AKA challenge; and authenticate the terminal node to the network.

[0055] In some examples of the sixth aspect, the binding information may be used by the terminal node until the terminal node is authenticated to the network.

[0056] In some examples of the sixth aspect, the binding information may comprise Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

[0057] In some examples of the sixth aspect, the non-terrestrial node may be incorporated in, or associated with, a satellite.

[0058] According to a seventh aspect of the subject disclosure, a non-terrestrial node (e.g., a non-terrestrial network node or a non-terrestrial Base Station (BS)) in a network or an apparatus in such a non-terrestrial node is provided. The non-terrestrial node or apparatus according to the seventh aspect comprises: means or modules for receiving, from a terminal node (e.g., a user device, User Equipment (UE) or Internet-of-Things (loT) device), a registration request (e.g., a receiver); means or modules for storing the registration request responsive to a link (e.g. a feeder link) between the non-terrestrial node and a terrestrial node (e.g., a terrestrial network node, a terrestrial Base Station (BS) or terrestrial gateway) of the network to forward the registration request not being available (e.g., a processor); means or modules for assigning binding information associated with the non-terrestrial node to the terminal node responsive to the link not being available (e.g., the processor); and means or modules for transmitting, to the terminal, a message comprising the binding information to be used by the terminal node (e.g., a transmitter). For example, the registration request may comprise a registration request to authenticate the terminal node to the network.

[0059] In some examples of the seventh aspect, the non-terrestrial node or apparatus further comprises means or modules for performing one or more of the examples according to the fifth aspect.

[0060] According to an eighth aspect of the subject disclosure, a non-terrestrial node (e.g., a non-terrestrial network node or a non-terrestrial Base Station (BS)) in a network or an apparatus in such a non-terrestrial node is provided. The non-terrestrial node or apparatus according to the sixth aspect comprises: circuitry to receive, from a terminal node (e.g., a user device, User Equipment (UE) or Internet-of-Things (loT) device), a registration request; circuitry to store the registration request responsive to a link (e.g. a feeder link) between the non-terrestrial node and a terrestrial node (e.g., a terrestrial network node, a terrestrial Base Station (BS) or a terrestrial gateway) of the network to forward the registration request not being available; circuitry to assign binding information associated with the non-terrestrial node to the terminal node responsive to the link not being available; and circuitry to transmit, to the terminal node, a message comprising the binding information to be used by the terminal node. For example, the registration request may comprise a registration request to authenticate the terminal node to the network.

[0061] In some examples of the eighth aspect, the non-terrestrial node or apparatus further comprises circuitry to perform one or more of the examples according to the fifth aspect.

[0062] According to a ninth aspect of the subject disclosure, a computer program product comprises program instructions stored on a computer readable medium to execute steps according to any one of the examples of the methods according to the first and fifth aspect as outlined above when said instructions are executed on a computer.

[0063] According to a tenth aspect of the subject disclosure, a non-transitory computer- readable medium containing computer-executable instructions which when run on one or more processors perform the steps according to any one of the examples of the methods according to the first and fifth aspect as outline above.

[0064] The above-noted aspects and features may be implemented in systems, apparatuses, methods, articles and / or non-transitory computer-readable media depending on the desired configuration. The subject disclosure may be implemented in and / or used with a number of different types of devices, including but not limited to cellular phones, tablet computers, wearable computing devices, portable media players, and any of various other computing devices.

[0065] This summary is intended to provide a brief overview of some of the aspects and features according to the subject disclosure. Accordingly, it will be appreciated that the abovedescribed features are merely examples and should not be construed to narrow the scope of the subject disclosure in any way. Other features, aspects, and advantages of the subject disclosure will become apparent from the following detailed description, drawings, and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0066] A better understanding of the subject disclosure can be obtained when the following detailed description of various embodiments is considered in conjunction with the following drawings, in which:

[0067] FIG. 1 shows a schematic diagram of an example (mobile / wireless) communication system or network;

[0068] FIG. 2 shows a schematic diagram of an example wireless device or entity;

[0069] FIG. 3 shows a schematic diagram of an example network node or entity;

[0070] FIG. 4 shows an example architecture of a non-terrestrial network;

[0071] FIG. 5 illustrates an overview of the operation in the regenerative satellite payload scenario;

[0072] FIGS. 6A and 6B illustrate scenarios of a serving satellite change during the feeder link disconnection due to a movement of the loT device or the satellite;

[0073] FIG. 6C illustrates a user plane protocol stack;

[0074] FIG. 6D illustrates a control plane protocol stack;

[0075] FIG. 7 illustrates a flowchart of a method or process for authenticating a terminal node to a network according to some embodiments, performed by the terminal node;

[0076] FIG. 8 illustrates a flowchart of a method or process for authenticating a terminal node to a network according to some embodiments, performed by a network node;

[0077] FIG. 9 illustrates an exemplary message sequence diagram of the methods or processes for authenticating a terminal node to a network according to some embodiments;

[0078] FIGS. 10A and 10B illustrate schematic block diagrams showing structures of apparatuses according to embodiments of the subject disclosure.DETAILED DESCRIPTION

[0079] The examples and embodiments set forth below represent information to enable those skilled in the art to practice the subject disclosure. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the description and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the description.

[0080] In the following description, numerous specific details are set forth. However, it is understood that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures, and techniques have not been shown in detail in order not to obscure the understanding of the description. Those of ordinary skill in the art, with the included description, will be able to implement appropriate functionality without undue experimentation.

[0081] References in the specification to "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0082] It is to be noted that the detailed description, at times, refers to one or more specifications being used as non-limiting and illustrative examples for certain architectures, network configurations and system deployments. More specifically, the detailed description refers to 3GPP standards, being used as non-limiting and illustrative examples. As such, the example embodiments provided herein can specifically employ terminology which is directly related thereto. Such terminology is only used in the context of the non-limiting and illustrative examples and is not intended to limit the example embodiments in any way. Rather, any other system configuration or deployment may be utilized while complying with what is described herein and / or example embodiments are applicable to it.

[0083] For example, various example embodiments are applicable in any (e.g., mobile / wireless) communication system, such as a 5G / NR system and a next-generation system beyond 5G. For example, various example embodiments are applicable in a 3GPP- standardized mobile / wireless communication system of Release 18 onwards.

[0084] Hereinafter, various example embodiments are described using several variants and / or alternatives. It is generally to be noted that, according to certain implementations or constraints, all the described variants and / or alternatives may be provided alone or in any conceivable combination (e.g., also including combinations of individual features of these various variants and / or alternatives).

[0085] As used herein, the words "comprising" and "including" should be understood as not limiting the example embodiments to consist of only those features that have been mentioned, and example embodiments may also contain, among other things, e.g., features, structures, units, modules, or the like, that have not been specifically mentioned.

[0086] As used herein, "at least one of the following: " and "at least one of " and similar wording, like "one or more of", where the list of two or more elements are joined by "and" or "or", mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0087] As used herein, according to various example embodiments, any operations of sending or receiving may comprise actual transmission or communication operations, i.e., transmitting or communicating associated messages or signals, but may additionally or alternatively comprise related processing operations, i.e., preparing / generating / issuingassociated messages or signals before sending and / or obtaining / handling / processing of associated messages or signals after receiving. For example, sending a message at / by an entity may comprise generating / issuing and / or transmitting / communicating thereof or a corresponding signal in / at / by the entity, and receiving a message at / by an entity may comprise obtaining / handling and / or processing thereof or a corresponding signal in / at / by the entity. As used herein, a message may refer to and / or encompass any kind of corresponding information, signal, or the like.

[0088] In the drawings, it is to be noted that lines / arrows interconnecting individual blocks or entities are generally meant to illustrate an operational coupling there-between, which may be a physical and / or logical coupling, which on the one hand is implementation-independent (e.g., wired, or wireless) and on the other hand may also comprise an arbitrary number of intermediary functional blocks or entities not shown. In flowcharts or sequence diagrams, the illustrated order of operations or actions is generally non-limiting and illustrative, and any other order of respective operations or actions is conceivable, if feasible.

[0089] Before explaining example embodiments in detail, certain general principles of a (mobile / wireless) communication system or network are briefly explained with reference to FIGS. 1 to 3 to assist in understanding the technology underlying the described example embodiments.

[0090] FIG. 1 illustrates an example of a (mobile / wireless) communication system or network 100 that may be used for wireless communications. Communication system or network 100 includes wireless devices or entities, such as UEs 110 (e.g., 110A-110C), and network nodes or entities, such as radio access nodes 120 (e.g., 120A-120B) (e.g., eNBs, gNBs, etc.), connected to one or more network nodes or entities 130 via an interconnecting network 125. Communication system or network 100 may use any suitable deployment scenarios. UEs 110 within coverage area 115 may each be capable of communicating directly with radio access nodes 120 over a wireless interface.

[0091] As an example, UE 110A may communicate with radio access node 120A over a wireless interface. That is, UE 110A may transmit wireless signals to and / or receive wireless signals from radio access node 120A. The wireless signals may contain voice traffic, data traffic, control signals, and / or any other suitable information.

[0092] As used herein, the term "user equipment" (UE) has the full breadth of its ordinary meaning and may refer to any type of wireless device or entity which can communicate with a network node or entity and / or with another UE in a cellular or mobile or wireless / mobile communication system. Examples of UE are target device, D2D UE, machine type UE or UE capable of machine-to-machine (M2M) communication, personal digital assistant, tablet, mobile terminal, smartphone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, ProSe UE, vehicle-to-vehicle (V2V) UE, V2X UE, MTC UE, eMTCUE, FeMTC UE, UE Cat 0, UE Cat Ml, narrow band loT (NB-IoT) UE, UE Cat NB1, etc. Example embodiments of a UE are described in more detail below with respect to FIG. 2.

[0093] In some embodiments, an area of wireless signal coverage 115 associated with a radio access node 120 may be referred to as a cell. However, particularly with respect to the fifth generation (5G) / New Radio (NR) mobile communication concepts, beams may be used instead of cells and, as such, it is important to note that concepts described herein are equally applicable to both cells and beams.

[0094] With respect to a beam-based mobile communication system, the radio access node 120 (base station) may transmit a beamformed signal to the UE 110 in one or more transmit directions (transmission beam, Tx beam). The UE 110 may receive the beamformed signal from the base station 120 in one or more receive directions (reception beam, Rx beam). The UE 110 may also transmit a beamformed signal to the base station 120 in one or more directions and the base station 120 may receive the beamformed signal from the UE 110 in one or more directions. The base station 120 and the UE 110 may determine the best receive and transmit directions, e.g., best in the sense of these directions leading to the highest link quality or fulfilling other quality conditions in the most suitable manner, for each of the base station / UE pairs.

[0095] The interconnecting network 125 may refer to any interconnecting system capable of transmitting audio, video, signals, data, messages, etc., or any combination of the preceding. The interconnecting network 125 may include all or a portion of a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.

[0096] In some embodiments, the network node 130 may be a core network node, managing the establishment of communication sessions and other various other functionalities for UEs 110. Examples of network node 130 may include mobile switching center (MSC), MME, serving gateway (SGW), packet data network gateway (PGW), operation and maintenance (O&M), operations support system (OSS), SON, positioning node (e.g., Enhanced Serving Mobile Location Center, E-SMLC), location server node, MDT node, etc. UEs 110 may exchange certain signals with the network node 130 using the non-access stratum (NAS) layer. In non-access stratum signaling, signals between UEs 110 and the network node 130 may be transparently passed through the radio access network. In some embodiments, radio access nodes 120 may interface with one or more network nodes 130 over an internode interface.

[0097] As used herein, the term "network node or entity" has the full breadth of its ordinary meaning and may correspond to any type of radio access node (or radio network node) or any network node, which can communicate with a UE and / or with another network node in acellular or mobile or wireless communication system. Examples of network nodes are NodeB, MeNB, SeNB, a network node may belonging to MCG or SCG, base station (BS), multistandard radio (MSR) radio access node such as MSR BS, eNodeB, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission point, transmission node, RRU, RRH, node in distributed antenna system (DAS), core network node (e.g., MSC, MME, etc.), O&M, OSS, Self-organizing Network (SON), positioning node (e.g., E-SMLC), MDT, test equipment, etc. Example embodiments of a network node are described in more detail below with respect to FIG. 3.

[0098] In some embodiments, radio access node 120 may be a distributed radio access node. The components of the radio access node 120, and their associated functions, may be separated into two main units (or sub-radio network nodes) which may be referred to as the central unit (CU) and the distributed unit (DU). Different distributed radio network node architectures are possible. For instance, in some architectures, a DU may be connected to a CU via dedicated wired or wireless link (e.g., an optical fiber cable) while in other architectures, a DU may be connected a CU via a transport network. Also, how the various functions of the radio access node 120 are separated between the CU(s) and DU(s) may vary depending on the chosen architecture.

[0099] Exemplary wireless communication systems are architectures standardized by the 3rd Generation Partnership Project (3GPP). A latest 3GPP based development is often referred to as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology (RAT). The various development stages of the 3GPP specifications are referred to as releases. More recent developments of the LTE are often referred to as LTE Advanced (LTE- A). The LTE (LTE- A) employs a radio mobile architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a core network known as the Evolved Packet Core (EPC). Base stations of such systems are known as evolved or enhanced Node Bs (eNBs) and provide E-UTRAN features such as user plane Packet Data Convergence / Radio Link Control / Medium Access Control / Physical layer protocol (PDCP / RLC / MAC / PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other RAT examples comprise those provided by base stations of systems that are based on technologies such as WLAN and / or Worldwide Interoperability for Microwave Access (WiMax). A base station can provide coverage for an entire cell or similar radio service area. Core network elements include Mobility Management Entity (MME), Serving Gateway (S-GW) and Packet Gateway (P-GW).

[0100] An example of a suitable communications system is the 5G or NR concept. Network architecture in NR may be similar to that of LTE- A. Base stations of NR systems may be known as next generation Node Bs (gNBs). Changes to the network architecture may depend on the need to support various radio technologies and finer Quality of Service (QoS) support,and some on-demand requirements for QoS levels to support Quality of Experience (QoE) of user point of view. Also network aware services and applications, and service and application aware networks may bring changes to the architecture. Those are related to Information Centric Network (ICN) and User-Centric Content Delivery Network (UC-CDN) approaches. NR may use multiple input-multiple output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates.

[0101] Future networks may utilize network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running instructions using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes, or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of the LTE or even be non-existent.

[0102] An example 5G core network (CN) comprises functional entities. The CN is connected to a UE via the radio access network (RAN). An UPF (User Plane Function) whose role is called PSA (PDU Session Anchor) may be responsible for forwarding frames back and forth between the DN (data network) and the tunnels established over the 5G towards the UEs exchanging traffic with the data network (DN). The UPF is controlled by an SMF (Session Management Function) that receives policies from a PCF (Policy Control Function). The CN may also include an AMF (Access & Mobility Function).

[0103] Generally, all concepts disclosed herein may be applicable to different communication networks, comprising but not limited to LTE, LTE-A, 5G, 5G advanced, 6G, and other future or already implemented networks.

[0104] FIG. 2 is a schematic diagram of an example wireless device, UE 110, according to certain example embodiments. UE 110 may include one or more of at least one transceiver 210, at least one processor 220, at least one memory 230, and at least one network interface 240. In certain example embodiments, the transceiver 210 facilitates transmitting wireless signals to and receiving wireless signals from radio access node 120 (e.g., via transmitter(s) (Tx), receiver(s) (Rx) and antenna(s)). The processor 220 executes instructions to provide some or all of the functionalities described herein as being provided by a wireless device / entity or UE, and the memory 230 stores the instructions executed by the processor 220. In some embodiments, the processor 220 and the memory 230 form processing circuitry.

[0105] The processor 220 may include any suitable combination of hardware to execute instructions and manipulate data to perform some or all the described functions of a wireless device or entity, such as the functions of UE 110 described herein. In some embodiments, the processor 220 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and / or other logic.

[0106] The memory 230 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and / or other instructions capable of being executed by a processor 220. Examples of memory 230 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or or any other volatile or non-volatile, non- transitory computer-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processor 220 of UE 110. For example, the memory 230 includes instructions causing the processor 220 to perform processing according to any corresponding methods described herein.

[0107] The network interface 240 is communicatively coupled to the processor 220 and may refer to any suitable device operable to receive input for UE 110, send output from UE 110, perform suitable processing of the input or output or both, communicate to other devices, or any combination thereof. The network interface 240 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

[0108] Other embodiments of UE 110 may include additional components beyond those shown in FIG. 2 that may be responsible for providing certain aspects of the wireless device’s functionalities, including any of the functionalities described herein and / or any additional functionalities (including any functionality necessary to support the mechanisms according to the subject disclosure). As an example, UE 110 may include input devices and circuits, output devices, and one or more synchronization units or circuits, which may be part of the processor 220. Input devices include mechanisms for entry of data into UE 110. For example, input devices may include input mechanisms, such as a microphone, input elements, a display, etc. Output devices may include mechanisms for outputting data in audio, video and / or hard copy format. For example, output devices may include a speaker, a display, etc.

[0109] In certain example embodiments, the wireless device UE 110 may comprise a series of modules configured to implement the functionalities of the wireless device described herein.

[0110] It will be appreciated that the various modules may be implemented as combination of hardware and software, for instance, the processor, memory, and transceiver(s) of UE 110shown in FIG. 2. Certain example embodiments may also include additional modules to support additional and / or optional functionalities.

[0111] FIG. 3 is a schematic diagram of an example radio access node 120 or network node or entity 130 according to certain example embodiments. Radio access node 120 or network node or entity 130 may include one or more of at least one transceiver 310, at least one processor 320, at least one memory 330, and at least one network interface 340. In certain example embodiments, the transceiver 310 facilitates transmitting wireless signals to and receiving wireless signals from wireless devices, such as UE 110 (e.g., via transmitter(s) (Tx), receiver(s) (Rx), and antenna(s)). The processor 320 executes instructions to provide some or all the functionalities described herein as being provided by the radio access node 120 or the network node or entity 130, the memory 330 stores the instructions executed by the processor 320. In some embodiments, the processor 320 and the memory 330 form processing circuitry. The network interface 340 can communicate signals to backend network components, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), core network nodes or radio network controllers, etc.

[0112] The processor 320 can include any suitable combination of hardware to execute instructions and manipulate data to perform some or all the described functions of the radio access node 120 or the network node or entity 130, such as those described herein. In some embodiments, the processor 320 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and / or other logic.

[0113] The memory 330 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and / or other instructions capable of being executed by a processor 320. Examples of memory 330 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or or any other volatile or non-volatile, non- transitory computer-readable and / or computer-executable memory devices that store information. For example, the memory 330 includes instructions causing the processor 320 to perform processing according to any corresponding methods described herein.

[0114] In certain example embodiments, the network interface 340 is communicatively coupled to the processor 320 and may refer to any suitable device operable to receive input for the radio access node 120 or the network node or entity 130, send output from the radio access node 120 or the network node or entity 130, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding. The network interface 340 may include appropriate hardware (e.g., port, modem, network interface card,etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

[0115] Other example embodiments of the radio access node 120 or the network node or entity 130 can include additional components beyond those shown in FIG. 3 that may be responsible for providing certain aspects of the node’s functionalities, including any of the functionalities described herein and / or any additional functionalities (including any functionality necessary to support the solutions described herein). The various different types of radio access nodes or network nodes may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partly or entirely different physical components.

[0116] Processors, interfaces, and memory similar to those described with respect to FIG. 3 may be included in other nodes or entities (such as UE 110, radio access node 120, etc.). Other nodes or entities may optionally include or not include a wireless interface (such as the transceiver described in FIG. 3).

[0117] In certain example embodiments, the radio access node 120 or the network node or entity 130 may comprise a series of modules configured to implement the functionalities of the radio access node 120 or the network node or entity 130 described herein.

[0118] It will be appreciated that the various modules may be implemented as combination of hardware and software, for instance, the processor, memory, and transceiver(s) of the radio access node 120 or the network node or entity 130 shown in FIG. 3. Certain example embodiments may also include additional modules to support additional and / or optional functionalities.

[0119] Before referring to FIGS. 7 to 9 and describing the methods for authenticating user equipment to a network according to some embodiments of the subject disclosure, some background information and aspects related to the subject disclosure will be provided.

[0120] As shown in FIG. 4, a non-terrestrial network (NTN) refers to a network, or a segment of networks using radio frequency (RF) resources on board of a satellite or UAS platform. Solutions to support NTN in 5G NR are discussed in 3GPP TR 38.821 (herein incorporated by reference in its entirety).

[0121] Practically speaking, NTN refers to a UE or loT device which is interfaced to a satellite (also referred to herein as a non-terrestrial node) via a service link, the satellite is interfaced to an NTN gateway (also referred to herein as a terrestrial node) via a feeder link, and the NTN gateway is interfaced to a Core Network and / or Home Network.

[0122] From Radio Access Network (RAN) architecture, particularly in view of the protocols that need to be supported by the satellite, the satellite may operate according to the following scenarios: a transparent satellite payload scenario and a regenerative satellite payload scenario.

[0123] In the transparent satellite payload scenario, the satellite does not terminate NR- Uu, i.e., the satellite repeats the NR-Uu radio interface from the feeder link to the service link and vice versa. In this scenario, the satellite does not process any payload.

[0124] In the regenerative satellite payload scenario, the satellite is supporting all radio network layer protocols and therefore implements regeneration of the signals received from the NTN gateway (i.e., from earth). In this scenario, the satellite is processing payloads such that the satellite can store and forward information and can establish communication to neighboring satellites via Inter Satellite Link (ISL).

[0125] In FIG. 5, an overview of the operation in the regenerative satellite payload scenario is illustrated. In this example, the satellite is supporting and providing full base station (gNB) functionality, i.e., all needed Radio Network Layer (RNL) protocols are supported by the satellite.

[0126] As shown, in the normal or default satellite operation, a Uu interface on the service link between the UE or loT device and the satellite and a NR interface between the satellite and the Access and Mobility Management Function (AMF) via the NTN gateway are implemented. That is, the NR interface is routed through the NTN gateway. The feeder link is between the satellite and NTN gateway.

[0127] In the store and forward satellite operation without either an active feeder link or an active service link, a stepwise approach using the service link (step A) if the feeder link is not active and the feeder link (step B) if the service link is not active is established.

[0128] The store and forward satellite operation may comprise the following use cases: mobile-originated (MO), mobile-terminated (MT) and inter satellite. Satellite access and use cases are discussed in 3GPP TR 22.865 (herein incorporated by reference in its entirety).

[0129] In the MO use case, a store and forward service between a UE with satellite access and an application server for a delay-tolerant / non-real-time loT NTN service in the case of a Mobile Originated message is to be realized.

[0130] For example, a company may offer a service of remote monitoring of fields and deploy and track battery-powered loT type UEs across the globe. All the loT remote monitoring UEs deployed include a 5G communication with satellite access. Some of the UEs are deployed in a remote area where there is no mobile coverage by Mobile Network Operator (MNO) and only satellite is possible. For the satellite access, the company may use the service of loT SAT for the 5G loT connectivity by satellite and loT SAT uses a Low Earth Orbit (LEO) constellation which supports store and forward operation mode. All loT remote monitoring UEs regularly send information related to the area the loT remote monitoring UEs are monitoring to the application server of the company and sometimes receive new parameters from the application server. In most of the cases, the messages exchanged are delay- tolerant / non-real-time loT.

[0131] In this example, the loT remote monitoring UEs need to send messages to the company’s application server. The UEs wait for satellite network coverage and send the messages when the satellite passes by. The loT remote monitoring UEs and the satellite providing coverage interact over the service link, allowing the UEs to transfer the messages to the satellite, which has no connectivity to the ground segment. And consequently, the satellite has to store locally the received message.

[0132] In the MT case, a store and forward service between a UE with satellite access and an application server for a delay-tolerant / non-real-time loT NTN service in the case of a Mobile Terminated message is to be realized.

[0133] For example, a company may offer a service of remote monitoring of fields and deploy and track battery-powered loT type UEs across the globe. All the loT remote monitoring UEs deployed include a 5G communication with satellite access. Some of the UEs are deployed in a remote area where there is no mobile coverage by the MNO and only satellite is possible. For the satellite access, the company uses the service of loT SAT for the 5G loT connectivity by satellite and loT SAT uses the LEO constellation which supports store and forward operation mode. All loT remote monitoring UEs regularly send information related to the area the loT remote monitoring UEs are monitoring to the application server of company and sometimes receive new parameters from the application server. In most of the cases, the messages exchanged are delay-tolerant / non-real-time loT.

[0134] In this example, the company’s application server may need to send new parameters to the loT remote monitoring UE. Based on the information provided by the network, the application server is aware that the communication with UE is in store and forward mode. The company’s application server message may send new parameters through dedicated messages by conventional means (e.g., IP routing, tunnels) to the network entry-point (e.g., a SCEF, PDN-GW, SMSC), and may provide additional information about the delivery priority, the acknowledgement, etc. to the network. This allows to enforce limitations on the amount of data to be transferred to the loT remote monitoring UE, establish forwarding priority to the UE, issue acknowledgement of the received data by the network to the application server, possibly with the additional information about the store and forward, e.g., estimated time to deliver the messages, and establish end-to-end acknowledgement policy.

[0135] Further, in this example, the network may store the message until the message can be delivered / relayed to a satellite expected to fly over and provide coverage to the destination loT remote monitoring UE. When the satellite is connected via the feeder link to the ground network, the message is uploaded into the satellite. All accumulated and stored MT messages are uploaded into the satellite via the feeder link. At the same time, all accumulated and stored MO messages are also delivered to 5GC via the same feeder link, which may cause a performance impact on the feeder link, satellite, and 5GC. When flying over the area that the loT remote monitoring UE is located, the satellite with the stored message triggers paging overthe service link for the UE to connect to the network. The stored message is delivered / downloaded from the satellite to the loT remote monitoring UE. Acknowledgment may be requested / issued.

[0136] Finally, in the inter satellite use case, store and forward operations are to be realized to sustain the user plane data during the feeder link disconnection between the satellite and the terrestrial gateway. In such scenarios, a serving satellite may change to another one during the time when the feeder link is unavailable. Such unavailable state of the feeder link may be caused by the temporary reconstruction or update of the terrestrial gateway.

[0137] FIGS. 6A and 6B illustrate scenarios of a serving satellite change during the feeder link disconnection due to a movement of the loT device (FIG. 6A) or the satellite (FIG. 6B).

[0138] As shown in FIG. 6A, a mobile loT device may move from the coverage of one satellite to the other, or as shown in FIG. 6B, a satellite may fly away and the other one will come and turn to serving a static loT device. Under such circumstances, the serving satellite may forward the stored user plane data to the next serving satellite through Inter Satellite Finks (ISE), and the next serving satellite may help forward the data to the gateway.

[0139] If the feeder link of the next satellite is also unavailable, the next satellite will continue the store operation until the recovery of the feeder link. In this way, for every single loT device, there will be only one satellite for data storage in the overall satellite system. The mobile operators will be easier to manage and maintain the data rather than dealing with the separate data which is belong to one device but among different satellites.

[0140] Significantly, during the period that the feeder link is unavailable, the serving satellite only stores or forwards (Inter-satellite) the data received from the loT device which is already able to send data to the application server through the mobile network with satellite access. Because of the disconnection separates the two parts of the mobile network temporarily, the part in the serving satellite will not be able to fulfill common communication procedures and refuse any access from an unregistered device. Furthermore, since the satellite may have limited data storage and the amount of loT devices may be large, a maximum storage for each loT device is to be pre-configured based on the application data characteristics, user subscriptions and overall performance of satellite communication system.

[0141] FIGS. 6C and 6D illustrate data flows for AS, NAS and UP for the communication between the UE or loT device and the Home Network (HN). More specifically, FIG. 6C illustrates a user plane protocol stack while FIG. 6D illustrates a control plane protocol stack.

[0142] As shown in FIG. 6C, the end-to-end communication path is between the UE or loT device and the UPF. The application function (AF) which is either sending to, or receiving from, the UE or loT device data (e.g., PDU) can be connected to the UPF. The PDCP security is between UE or loT device and satellite (in this case the satellite A). The device data (PDU) will be transferred over the SDAP (Uu-interface) and will be protected by PDCP (AS security).The device data (PDU) will be transferred over the GTP-u (NG-interface) and will be protected by either NDS / IPsec or DTLS.

[0143] As shown in FIG. 6D, the end-to-end communication path is between UE or loT device and the gNB (RRC protocol), which mainly refer to AS, or is between UE or loT device and AMF (NAS protocol). The application function (AF) which is either sending to, or receiving from, the UE or loT device data (e.g., PDU) can be connected to the AMF. The device data (PDU) will be transferred end-to-end over NAS and will be protected by NAS security.

[0144] Referring again to FIG. 5, the operation in the regenerative satellite payload scenario may be separated in the normal or default satellite operation mode and the store and forward satellite operation mode. In the normal or default satellite operation mode, the feeder link and service link is available and therefore the UE or loT device can be authenticated with Core Network (CN) and UE or loT device can setup RRC connection with satellite. In this normal or default operation mode, the NAS and AS security contexts have been established and can be maintained. The UE or loT device can change between the different RRC modes. On the other hand, in the store and forward satellite operation mode, either the feeder link (step A of FIG. 5) or the service link (step B of FIG. 5) is not active and therefore the satellite moves from being connected to the UE in step A to being connected to the ground network in step B. This store and forward satellite operation mode is introducing the AS and NAS mobility, i.e., the UE or loT device or the satellite is moving while AS / NAS contexts exist.

[0145] For the mobility scenarios described above, the AS mobility is referring to the UE or loT device or the satellite is moving and therefore the AS (security) context need to be moved to the new satellite, while the NAS mobility is referring to the NAS (security) context need to be moved to the new Home Network.

[0146] Accordingly, mechanisms for executing the UE or loT registration procedure as specified in 3GPP TS 33.501 (herein incorporated by reference in its entirety) in such scenarios and performing AKA challenge are required. That is, mechanisms for processing the messages in case there is no feeder link available are required. In addition, mechanisms for setting up the NAS security context and the AS security context if the feeder link is not present are required.

[0147] Now, exemplary methods for authenticating user equipment to a network according to some embodiments of the subject disclosure will be described.

[0148] FIG. 7 illustrates a flowchart of a method 700 or process for authenticating a terminal node to a network according to some embodiments. The network according to the embodiments of the subject disclosure comprises a non-terrestrial network as described above with reference to FIG. 4.

[0149] The method 700 is performed by a terminal node such as a user device (e.g., UE or loT device), or by an apparatus in, or for use in, such a terminal node. For example, the terminal node may be represented by any one of the wireless devices, such as UEs 110A-110B of the wireless network 100 as described above with reference to FIG. 1, or the wireless device 110as described above with reference to FIG. 2, or the user equipment of the non-terrestrial network as described above with reference to FIG. 4.

[0150] The non-terrestrial network comprises one or more non-terrestrial network nodes or network functions such as base stations (e.g., gNBs 120A, 120B) incorporated in, or associated with, satellites or UAS platforms, and one or more terrestrial network nodes or network functions such as base stations (e.g., gNBs 120A, 120B), gateways, or the like, which are ground-based.

[0151] The terminal node is interfaced to the non-terrestrial network (e.g., network 100) via a satellite. More specifically, the terminal node is located in an area (i.e., a cell 115) served by one of the non-terrestrial base stations (e.g., gNBs 120A, 120B) and thereby enabled to use services provided by the network.

[0152] As already mentioned above, the satellite and thus the non-terrestrial base station incorporated in, or associated with, the satellite may be moving with respect to a ground reference (e.g., the earth’s surface). The link between the non-terrestrial base station and the terminal node (i.e., the service link) and / or the link between the non-terrestrial base station and the gateway (i.e., the feeder link) may therefore become not available. In other words, the feeder link or the service link will be disconnected due to the movement of the non-terrestrial base station.

[0153] Once the terminal node needs to authenticate to the non-terrestrial network to use services provided by the non-terrestrial network, terminal node triggers an authentication procedure via the non-terrestrial base station (i.e., via the satellite). More specifically, the terminal node may trigger a primary authentication procedure to the Home Network.

[0154] The method 700 for authenticating the terminal node to the non-terrestrial network starts at block 710. At block 710, the terminal node transmits a registration request to authenticate the terminal node to the non-terrestrial network. More specifically, the terminal node triggering the (primary) authentication procedure transmits a message requesting registration towards the non-terrestrial network. Since the terminal node is interfaced to the non-terrestrial network via the satellite, the terminal node transmits the registration request to the non-terrestrial base station (i.e., to the satellite).

[0155] In some examples, the registration request comprises an identifier associated with the terminal node. Typically, the identifier comprises a Subscription Concealed Identifier (SUCI) of the terminal node. The SUCI is a privacy preserving identifier containing a concealed Subscription Permanent Identifier (SUPI) and thus a 5G globally unique SUPI allocated to each subscriber and defined in 3GPP specification TS 23.501 (herein incorporated by reference in its entirety).

[0156] In response to transmitting the registration request at block 710, the terminal node receives a message from the non-terrestrial node at block 720. The message (e.g., a RRC message) comprises binding information associated with the non-terrestrial node. In someexamples, the binding information may comprise a Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node, such as a SAT RNTI. The binding information is assigned to the terminal node and used by the terminal node for purposes of authentication via the non-terrestrial node (i.e., purposes of store and forward authentication). In some examples, the terminal node may use the binding information received with the message at block 720 until the terminal node is authenticated to the non-terrestrial network. That is, the terminal node uses the SAT RNTI until the primary authentication procedure is completed.

[0157] In some examples, the method 700 may further comprise prior to transmitting the registration request (block 710) that the terminal node establishes a connection with the nonterrestrial base station. More specifically, the terminal node may perform a procedure to establish the connection (e.g., a RRC connection) between the terminal node and the nonterrestrial base station as specified in 3GPP specification.

[0158] In some examples, the method 700 may further comprise that the terminal node is paged by the non-terrestrial base station. For example, the terminal node may receive a paging message from the non-terrestrial base station. The paging message may use the binding information assigned to the terminal node and received with the message at block 720.

[0159] In some examples, in which the (service) link between the terminal node and the non-terrestrial base station is not available (i.e., disconnected) due to movement of the satellite or the terminal node, the terminal node may be interfaced to the non-terrestrial network via one or more other non-terrestrial base stations. The one or more other non-terrestrial base stations act as relay nodes between the terminal node and the non-terrestrial base station which assigned the binding information (i.e., the SAT RNTI) to the terminal node. In such examples, responsive to the link between the terminal node and the non-terrestrial base station being available via the one or more other non-terrestrial base stations, the terminal node is paged by the non-terrestrial base station via the one or more other non-terrestrial base stations. For example, the terminal node may receive the paging message from the non-terrestrial base station via the one or more other non-terrestrial base stations, using the binding information assigned by the non-terrestrial base station to the terminal node and received with the message at block 720.

[0160] In some examples, the method 700 may further comprise that the terminal node receives an Authentication and Key Agreement (AKA) challenge from the non-terrestrial network (e.g., the Home Network) to authenticate the terminal node. The terminal node receives the AKA challenge from the non-terrestrial base station. In response to receiving the AKA challenge, the terminal node may perform the authentication procedure and respond by transmitting a response to the AKA challenge. The terminal node transmits the response to the non-terrestrial base station. The terminal node will then be authenticated to the non-terrestrial network in accordance with the authentication procedure. Once the authentication procedureto the non-terrestrial network via the non-terrestrial base station is successful, Non-Access Stratum (NAS) and / or Access Stratum (AS) context procedures may be performed.

[0161] In examples, in which the (service) link between the terminal node and the nonterrestrial base station is not available (i.e., disconnected) due to movement of the satellite or terminal node while the (service) link between the terminal node and the non-terrestrial base station via the one or more other non-terrestrial base stations is available, the terminal node may receive the AKA challenge from the non-terrestrial base station via the one or more other non-terrestrial base stations and may transmit the response to the AKA challenge to the nonterrestrial base station via the one or more other non-terrestrial base stations.

[0162] FIG. 8 illustrates a flowchart of a method 800 or process for authenticating a terminal node to a network according to some embodiments. The network according to the embodiments of the subject disclosure comprises a non-terrestrial network as described above with reference to FIG. 4.

[0163] The method 800 is performed by a network (e.g., a network node or network function, including a Base Station (BS)). The method 800 may also be performed by an apparatus in, or for use in, such a network node or network function. For example, the network node may be represented by any one of the networks nodes, such as gNBs 120A-120B or network node 130 of the wireless network 100 as described above with reference to FIG. 1, the network node 120 / 130 as described above with reference to FIG. 3, or the satellite of the nonterrestrial network as described above with reference to FIG. 4. More specifically, the nonterrestrial network comprises one or more non-terrestrial network nodes or network functions such as base stations (e.g., gNBs 120A, 120B) incorporated in, or associated with, satellites or UAS platforms, and one or more terrestrial network nodes or network functions such as base stations (e.g., gNBs 120A, 120B), gateways, or the like, which are ground-based. That is, method 800 may typically be performed by a non-terrestrial basis station incorporated in, or associated with, a satellite or UAS platform.

[0164] The non-terrestrial basis station (e.g., gNBs 120A, 120B) may serve a cell (e.g., a cell 115 of FIG. 1) in an area of which a terminal node such as a user device (e.g., UE or loT device), is located. The terminal node is interfaced to the non-terrestrial network via the satellite. More specifically, the terminal node is located in the area served by the non-terrestrial base station and thereby enabled to use services provided by the network.

[0165] As already mentioned above, the satellite and thus the non-terrestrial base station incorporated in, or associated with, the satellite may be moving with respect to the ground reference (e.g., the earth’s surface). The link between the non-terrestrial base station and the terminal node (i.e., the service link) and / or the link between the non-terrestrial base station and the gateway (i.e., the feeder link) may therefore become not available. In other words, the feeder link or the service link will be disconnected due to the movement of the non-terrestrial base station.

[0166] Once the terminal node needs to authenticate to the non-terrestrial network to use services provided by the non-terrestrial network, terminal node triggers an authentication procedure via the non-terrestrial base station (i.e., via the satellite). More specifically, the terminal node may trigger a primary authentication procedure to the Home Network.

[0167] The method 800 for authenticating the terminal node to the non-terrestrial network starts at block 810. At block 810, the non-terrestrial base station receives a registration request to authenticate the terminal node from the terminal node. More specifically, the non-terrestrial base station receives a message requesting registration transmitted by the terminal node in response to the (primary) authentication procedure being triggered. Since the terminal node is interfaced to the non-terrestrial network via the satellite, the terminal node transmits the registration request to the non-terrestrial base station (i.e., to the satellite).

[0168] In some examples, the registration request comprises an identifier associated with the terminal node. Typically, the identifier comprises a Subscription Concealed Identifier (SUCI) of the terminal node as described above.

[0169] In cases, in which the (feeder) link between the non-terrestrial base station and the terrestrial base station (e.g., the gateway) is not available (i.e., disconnected) due to movement of the satellite, the non-terrestrial base station is not able to forward the registration request received from the terminal device at block 810 to the terrestrial base station. The non-terrestrial base station therefore stores the registration request (block 820) for being forwarded to the terrestrial base station once the link between the non-terrestrial base station and the terrestrial base station is available. That is, the non-terrestrial base station operates in accordance with the store and forward mode of operation.

[0170] Responsive to the (feeder) link between the non-terrestrial base station and the terrestrial base station to forward the registration request not being available, the non-terrestrial base station assigns binding information associated with the non-terrestrial base station to the terminal node (block 830). In some examples, the binding information may comprise a Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial base station, such as a SAT RNTI. The binding information assigned to the terminal node is to be used by the terminal node for purposes of authentication via the non-terrestrial base station (i.e., purposes of store and forward authentication). The terminal node may use the binding information assigned by the non-terrestrial base station until the terminal node is authenticated to the nonterrestrial network. That is, the terminal node uses the SAT RNTI until the primary authentication procedure is completed.

[0171] At block 840, the non-terrestrial base station transmits the binding information assigned to the terminal node to the terminal node. More specifically, the non-terrestrial base station transmits a message (e.g., a RRC message) including the binding information to the terminal node.

[0172] In some examples, the method 800 may further comprise prior to receiving the registration request (block 810) that the terminal node establishes a connection with the nonterrestrial base station. More specifically, the non-terrestrial base station may perform a procedure to establish the connection (e.g., a RRC connection) between the terminal node and the non-terrestrial base station as specified in 3GPP specification.

[0173] In some examples, the method 800 may further comprise that the non-terrestrial base station determines that the link (i.e., the feeder link) between the non-terrestrial base station and the terrestrial base station is available. That is, the non-terrestrial base station determines that the non-terrestrial base station is connected to the terrestrial base station via the link. Responsive to the link being available, the non-terrestrial base station may forward the registration request stored at block 820 to the terrestrial base station via the link. By forwarding the registration request, the (primary) authentication procedure triggered by the terminal node is continued.

[0174] In response to forwarding the registration request to the terrestrial base station, the non-terrestrial base station may receive an Authentication and Key Agreement (AKA) challenge from the non-terrestrial network (e.g., the Home Network) to authenticate the terminal node. The non-terrestrial base station receives the AKA challenge from the terrestrial base station via the link between the non-terrestrial base station and the terrestrial base station. The non-terrestrial base station may further store an association of the AKA challenge received from the non-terrestrial network and the binding information assigned to the terminal node. In some examples, the association of the AKA challenge and the binding information may be stored in the form of a mapping in a mapping table.

[0175] In some examples, the method 800 may further comprise that the non-terrestrial base station pages the terminal node. For example, the non-terrestrial base station may transmit a paging message to the terminal node. The paging message may use the binding information assigned to the terminal node at block 830.

[0176] In some examples, in which the (service) link between the terminal node and the non-terrestrial base station is not available (i.e., disconnected) due to movement of the satellite or the terminal node, the terminal node may be interfaced to the non-terrestrial network via one or more other non-terrestrial base stations. The one or more other non-terrestrial base stations act as relay nodes between the terminal node and the non-terrestrial base station which assigned the binding information (i.e., the SAT RNTI) to the terminal node. In such examples, responsive to the link between the terminal node and the non-terrestrial base station being available via the one or more other non-terrestrial base stations, the non-terrestrial base station pages the terminal node via the one or more other non-terrestrial base stations. For example, the non-terrestrial base station may transmit the paging message to the terminal node via the one or more other non-terrestrial base stations, using the binding information assigned to the terminal node at block 830.

[0177] In some examples, the method 800 may further comprise that the non-terrestrial base station transmits the AKA challenge received from the non-terrestrial network and stored at the non-terrestrial base station to the terminal node. In response to transmitting the AKA challenge, the non-terrestrial base station may receive a response to the AKA challenge from the terminal node. The response may be or include the result of performing the authentication procedure at the terminal node. The non-terrestrial base station will authenticate the terminal node to the non-terrestrial network in accordance with the authentication procedure. Once the authentication procedure to the non-terrestrial network is successful, Non-Access Stratum (NAS) and / or Access Stratum (AS) context procedures may be performed via the nonterrestrial base station.

[0178] In examples, in which the (service) link between the terminal node and the nonterrestrial base station is not available (i.e., disconnected) due to movement of the satellite or the terminal node while the link between the terminal node and the non-terrestrial base station via the one or more other non-terrestrial base stations is available, the non-terrestrial base station may transmit the AKA challenge to the terminal node via the one or more other nonterrestrial base stations and may receive the response to the AKA challenge from the terminal node via the one or more other non-terrestrial base stations.

[0179] An exemplary message sequence diagram of the methods or processes for authenticating a terminal node to a network according to some embodiments will now be described with reference to FIG. 9. The network according to the embodiments of the subject disclosure comprises a non-terrestrial network as described above with reference to FIG. 4.

[0180] The non-terrestrial network may comprise the UE or loT device (e.g., a terminal node performing the methods of FIG. 7), one or more non-terrestrial network nodes or network functions (e.g., a non-terrestrial node performing the methods of FIG. 8) incorporated in, or associated with, satellites or UAS platforms, and one or more terrestrial network nodes or network functions such as base stations, gateways, or the like, which are ground-based. For example, as shown in FIG. 9, the non-terrestrial network may comprise a first non-terrestrial base station incorporated in, or associated with, a first satellite (SAT#l+gNB) and one or more second non-terrestrial base stations incorporated in, or associated with, second satellites (SAT#2+gNB). The first non-terrestrial base station may represent the non-terrestrial base station performing the methods of FIG. 8. The second non-terrestrial base stations may represent the other non-terrestrial base stations described above in the methods of FIGS. 7 and 8. The non-terrestrial network may also comprise a gateway (GW), a terrestrial base station (gNB; not shown) and a Core Network (CN)Z Home Network (HN). The (service) link between the UE and the first non-terrestrial base station (SAT#l+gNB) or between the UE and the first non-terrestrial base station (SAT#l+gNB) via the one or more second non-terrestrial base stations incorporated in, or associated with, second satellites (SAT#2+gNB) may be established. Between the first non-terrestrial base station (SAT#l+gNB) and the gateway (GR)or the terrestrial base station (gNB), a (feeder) link may be established. The gateway (GR) or the terrestrial base station (gNB) may be connected to the Core Network (CN) / Home Network (HN).

[0181] In the exemplary message sequence diagram, the UE is interfaced to the Home Network (HN) via the satellite. As the satellite is moving with respect to the earth’s surface, the feeder link between the satellite (i.e., SAT#l+gNB) and the gateway (GW) or the terrestrial base station (not shown) and / or the service link between the UE and the satellite (i.e., SAT#l+gNB) will become dis- / connected (i.e., un- / available). In some cases, the UE needs to authenticate to the Home Network (HN) and therefore needs to trigger the (primary) authentication procedure. For example, the UE needs to trigger the (primary) authentication procedure to authenticate to the Home Network (HN), thereby allowing the UE to use services provided by the Home Network (HN). In case the feeder link is not available (which is typically not known to the UE), the UE is triggering the registration process towards the satellite (SAT#l+gNB) and the satellite (SAT#l+gNB) makes functions available to compensate the inactive and therefore not available (i.e., missing) feeder link. In some examples, the satellite (SAT#l+gNB) may also make functions available to compensate the inactive and therefore not available service link. According to embodiments of the subject disclosure, the satellite (SAT#l+gNB) is to create and maintain binding information specific per UE and different for uplink and downlink traffic. For example, in downlink, the satellite (SAT#l+gNB) may trigger a UE paging procedure via an Inter Satellite Link (ISL). That is, the satellite (SAT#l+gNB) may trigger the UE paging procedure via one or more other satellites (SAT#2+gNB). In uplink, the satellite (SAT#l+gNB) may search for another (neighboring) satellite (SAT#2+gNB) which may act as a relay (i.e., a relay SAT) towards the Home Network (HN).

[0182] In the exemplary message sequence diagram, the satellite (SAT#l+gNB) is supporting all radio network layer protocols and therefore implements regeneration of the signals received from terrestrial network node (i.e., from earth). That is, the satellite (SAT#l+gNB) is operating in the regenerative mode and thus is processing payloads (i.e., the satellite can store and forward information and can establish communication to neighboring satellites via ISL). In other examples (not shown), the satellite (SAT#l+gNB) may be operating in the transparent mode as described above.

[0183] According to the exemplary message sequence diagram, the (primary) authentication procedure to authenticate the UE to the Home Network (HN) via the relay SAT (i.e., SAT#2+gNB) comprises the following operations:

[0184] In operation la, the UE may establish a RRC connection via the (service) link with the satellite (SAT#l+gNB). In case the satellite (SAT#l+gNB) is operating in the regenerative mode, the UE may prolong a UE timer.

[0185] In operation lb, the satellite (SAT#l+gNB) may determine that the (feeder) link between the satellite (SAT#l+gNB) and the gateway (GW) or the terrestrial base station (gNB)is not available (i.e., the feeder link is disconnected due to movement of the satellite (SAT#l+gNB)). The information that the feeder link is not available is typically not known by the UE. In other words, the satellite (SAT#l+gNB) does not provide indication to the UE that the feeder link is not available.

[0186] In operation 2a, the UE needs to authenticate to the Home Network (HN) and therefore triggers the (primary) authentication procedure. Accordingly, the UE may send a registration request via the service link to the satellite (SAT#l+gNB). Typically, the registration request may be sent from the UE with the SUCI of the UE. In some examples, the registration request may include the SUCI.

[0187] In operation 2b, the satellite (SAT#l+gNB) may store the registration request received from the UE. In some examples, the satellite (SAT#l+gNB) is operating in the regenerative mode and thus is to store and forward information (e.g., the registration request received from the UE). As described above, the feeder link is not available so that the satellite (SAT#l+gNB) cannot forward the registration request to the gateway (GW) or the terrestrial base station (gNB) but stores the registration request for being forwarded once the feeder link is available.

[0188] In operation 2c, the satellite (SAT#l+gNB) may assign binding information to the UE. For example, the satellite (SAT#l+gNB) may assign a temporary SAT RNTI ID for store and forward authentication purposes. In addition, the satellite (SAT#l+gNB) may send the assigned binding information to the UE. For example, the satellite (SAT#l+gNB) may send a RRC message including the assigned binding information. The UE is to use the binding information assigned by the satellite (SAT#l+gNB) until the (primary) authentication procedure is completed. In some examples, the binding information is used for all UE specific information which is to be stored and forwarded and differs between uplink and downlink as further described below.

[0189] Further, in the exemplary message sequence diagram shown in FIG. 9, the satellite (SAT#l+gNB) is moving causing the service link between the satellite (SAT#l+gNB) and the UE to be not available any longer.

[0190] In operation 2d, the satellite (SAT#l+gNB) may determine that the feeder link between the satellite (SAT#l+gNB) and the gateway (GW) or the terrestrial base station (gNB) is available (i.e., the feeder link is connected).

[0191] In operation 3a, in response to determining that the feeder link is available, the satellite (SAT#l+gNB) may forward the registration request received from the UE (operation 2a) and stored at the satellite (SAT#l+gNB) (operation 2b) towards the Core Network (CN) / Home Network (HN) via the gateway (GW) or the terrestrial base station (gNB). For example, the satellite (SAT#l+gNB) may forward the registration request as NAS payload to the Core Network (CN). The Core Network (CN) may send the registration request with the SUCI to theHome Network (HN), which responds by sending an AKA challenge towards the satellite (SAT#l+gNB).

[0192] In operation 3b, the satellite (SAT#l+gNB) may store the AKA challenge received from the Home Network (HN). More specifically, the satellite (SAT#l+gNB) may store the AKA challenge against the binding information assigned to the UE (e.g., the SAT RNTI ID). The satellite (SAT#l+gNB) may maintain a mapping table for all UEs and store a mapping of the AKA challenge and the binding information assigned to the UE in the mapping table.

[0193] As described above, due to the movement of the satellite (SAT#l+gNB), the service link between the satellite (SAT#l+gNB) and the UE is not available. However, the service link may exist between the UE and the satellite (SAT#l+gNB) via the relay SAT (SAT#2+gNB).

[0194] In operation 4a, the satellite (SAT#l+gNB) may page the UE using the binding information (e.g., the SAT RNTI ID) via the relay SAT (SAT#2+gNB) or other satellites (not shown) which belong to a satellite group.

[0195] In operation 4b, the UE may establish a RRC connection with another satellite (SAT#2+gNB) acting as a relay gNB towards the satellite (SAT#l+gNB). For example, an ISL may be established between the satellites (SAT#l+gNB and SAT#2+gNB). The satellite (SAT#l+gNB) may page the UE by routing to the other satellite (SAT#2+gNB) which relays the paging to the UE.

[0196] In operation 4c, the satellite (SAT#l+gNB) may forward the AKA challenge stored at the satellite (SAT#l+gNB) to the UE via the relaying other satellite (SAT#2+gNB).

[0197] In the exemplary message sequence diagram shown in FIG. 9, operations 4a to 4c represent downlink communications.

[0198] In operation 4d, the UE sends an AKA response to the satellite (SAT#l+gNB) via the relaying other satellite (SAT#2+gNB). In the exemplary message sequence diagram shown in FIG. 9, operation 4d represents uplink communication.

[0199] In operation 5, the (primary) authentication for store and forward may be performed. Once the (primary) authentication is successful, a procedure for NAS context in accordance with 3GPP standard TS 33.501 (herein incorporated by reference in its entirety) may be performed via the relaying other satellite (SAT#2+gNB).

[0200] According to the exemplary message sequence diagram shown in FIG. 9, the (primary) authentication of the UE to the Home Network for store and forward using the binding information (i.e., the SAT RNTI which is visible in RRC messages towards UE) is enabled.

[0201] FIGS. 10A and 10B illustrate schematic block diagrams showing structures of apparatuses according to embodiments of the subject disclosure.

[0202] In FIGS. 10A and 10B, the blocks are basically configured to perform respective methods, procedures and / or functions as described above. It is to be noted that the individualblocks are meant to illustrate respective functional blocks implementing a respective function, process, or procedure, respectively. Such functional blocks are implementation-independent, i.e., may be implemented by means of any kind of hardware or software or combination thereof, respectively.

[0203] An apparatus according to at least one embodiment may represent or realize / embody (e.g., a part of) a UE or loT device as an example of a wireless device or entity. Such apparatus may be illustrated or realized as is shown in FIG. 2. The apparatus or the at least one processor 220 (e.g., together with instructions stored in the at least one memory 230) may be configured to transmit, to a non-terrestrial node, a registration request to authenticate to the network.

[0204] Further, the apparatus or the at least one processor 220 (e.g., together with instructions stored in the at least one memory 230) may be configured to receive, from the nonterrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the UE or loT device, the binding information being assigned to the UE or loT device.

[0205] Such apparatus may be illustrated or realized as is shown in FIG. 10A as apparatus 1000. The apparatus 1000 may comprise (at least) one or more unit / means / circuitry, denoted by transmitting section 1010, which represent any implementation for (or configured to) transmitting, to a non-terrestrial node, a registration request to authenticate to the network, and (at least) one or more unit / means / circuitry, denoted by receiving section 1020, which represent any implementation for (or configured to) receiving, from the non-terrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the UE or loT device, the binding information being assigned to the UE or loT device.

[0206] As indicated by dashed lines, the apparatus 1000 may comprise (at least) one or more unit / means / circuitry, denoted by processing section 1030, which represent any implementation for (or configured to) performing one or more operations described above.

[0207] Further, an apparatus according to at least one embodiment may represent or realize / embody (e.g., a part of) a non-terrestrial network entity (such as any kind of base station, or the like, incorporated in a satellite) as an example of a non-terrestrial network device or entity.

[0208] Such apparatus may be illustrated or realized as is shown in FIG. 3. The apparatus or the at least one processor 320 (e.g., together with instructions stored in the at least one memory 330) may be configured to receive, from a UE or loT device, a registration request to authenticate to the network.

[0209] Further, the apparatus or the at least one processor 320 (e.g., together with instructions stored in the at least one memory 330) may be configured to store the registration request and assign binding information associated with the non-terrestrial network entity to the UE or loT device responsive to a link between the non-terrestrial network entity and a terrestrialnetwork entity (e.g., such as any kind of ground-based base station or the like) of the network to forward the registration request not being available. Also, the apparatus or the at least one processor 320 (e.g., together with instructions stored in the at least one memory 330) may be configured to transmit, to the UE or loT device, a message comprising the binding information to be used by the UE or loT device.

[0210] Such apparatus may be illustrated or realized as is shown in FIG. 10B as apparatus 1100. The apparatus 1100 may comprise (at least) one or more unit / means / circuitry, denoted by receiving section 1110, which represent any implementation for (or configured to) receiving, from a UE or loT device, a registration request to authenticate to the network, (at least) one or more unit / means / circuitry, denoted by storing and assigning (i.e., processing) section 1120, which represent any implementation for (or configured to) storing the registration request and assigning binding information associated with the non-terrestrial network entity to the UE or loT device responsive to a link between the non-terrestrial network entity and a terrestrial network entity of the network to forward the registration request not being available, and (at least) one or more unit / means / circuitry, denoted by transmitting section 1130, which represent any implementation for (or configured to) transmitting, to the UE or loT device, a message comprising the binding information to be used by the UE or loT device.

[0211] The apparatus 1100 may comprise (at least) one or more unit / means / circuitry (not shown in FIG. 10B), which represent any implementation for (or configured to) performing one or more operations described above.

[0212] For further details regarding the operability / functionality of the apparatuses (or units / means thereof) according to some embodiments of the subject disclosure, reference is made to the above description in connection with any one of FIGS. 1 to 10, respectively.

[0213] It should be understood that the apparatuses may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and / or reception. Although the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities.

[0214] It is noted that whilst embodiments have been described in relation to LTE and 5G NR, similar principles can be applied in relation to other networks and communication systems where enforcing fast connection re-establishment is required. Therefore, although certain embodiments were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

[0215] It is also noted herein that while the above describes exemplary embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the subject disclosure.

[0216] In general, the various exemplary embodiments may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects of the subject disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor, or other computing device, although the subject disclosure is not limited thereto. While various aspects of the subject disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques, or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0217] Example embodiments of the subject disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and / or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computerexecutable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it.

[0218] Further in this regard it should be noted that any blocks of the logic flow as in the figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks, and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

[0219] The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), FPGA, gate level circuits and processors based on multicore processor architecture, as non-limiting examples.

[0220] Example embodiments of the subject disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0221] The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of the subject disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of the subject disclosure as defined in the appended claims. Indeed, there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims

CLAIMS:

1. An apparatus of a non-terrestrial node in a network, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform:- receive, from a user equipment, a registration request;- responsive to a link between the non-terrestrial node and a terrestrial node of the network to forward the registration request not being available: store the registration request; and assign binding information associated with the non-terrestrial node to the user equipment; and- transmit, to the user equipment, a message comprising the binding information to be used by the user equipment.

2. The apparatus of claim 1, wherein the registration request comprises an identifier associated with the user equipment.

3. The apparatus of claim 2, wherein the identifier comprises a Subscription Concealed Identifier (SUCI) of the user equipment.

4. The apparatus of any one of claims 1 to 3, wherein the instructions are further configured to cause the apparatus at least to:- perform a procedure to establish a connection to the user equipment.

5. The apparatus of claim 4, wherein the connection comprises a Radio Resource Control (RRC) connection between the user equipment and the non-terrestrial node.

6. The apparatus of any of claims 1 to 5, wherein the instructions are further configured to cause the apparatus at least to:- responsive to the link being available, forward the registration request to the terrestrial node;- receive, from the terrestrial node, an Authentication and Key Agreement (AKA) challenge; and- store an association of the AKA challenge and the binding information.

7. The apparatus of claim 6, wherein the association of the AKA challenge and the binding information is stored in a mapping table.

8. The apparatus of claim 6 or 7, wherein the instructions are further configured to cause the apparatus at least to:- transmit, to the user equipment, a paging message using the binding information.

9. The apparatus of any one of claims 6 to 8, wherein the instructions are further configured to cause the apparatus at least to:- transmit, to the user equipment, the AKA challenge;- receive, from the user equipment, a response to the AKA challenge; and- authenticate the user equipment to the network.

10. The apparatus of any one of claims 6 to 9, wherein the instructions are further configured to cause the apparatus at least to:- responsive to a link between the user equipment and the non-terrestrial node available via another non-terrestrial node acting as a relay node, transmit, to the user equipment via the other non-terrestrial node, a paging message using the binding information.

11. The apparatus of claim 10, wherein the instructions are further configured to cause the apparatus at least to:- transmit, to the user equipment via the other non-terrestrial node, the AKA challenge;- receive, from the user equipment via the other non-terrestrial node, a response to the AKA challenge; and- authenticate the user equipment to the network.

12. The apparatus of any one of claims 1 to 11 , wherein the binding information is to be used by the user equipment until the user equipment is authenticated to the network.

13. The apparatus of any one of claims 1 to 12, wherein the binding information comprises Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

14. The apparatus of any one of claims 1 to 13, wherein the non-terrestrial node is incorporated in a satellite.

15. An apparatus of a user equipment in a network, comprising: at least one processor; and at least one memory storing instructions, that, when executed by the at least one processor, cause the apparatus at least to perform:- transmit, to a non- terrestrial node, a registration request; and- receive, from the non-terrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the user equipment, the binding information being assigned to the user equipment.

16. The apparatus of claim 15, wherein the registration request comprises an identifier associated with the user equipment.

17. The apparatus of claim 16, wherein the identifier comprises a Subscription Concealed Identifier (SUCI) of the user equipment.

18. The apparatus of any one of claims 15 to 17, wherein the instructions are further configured to cause the apparatus at least to:- perform a procedure to establish a connection to the non-terrestrial node.

19. The apparatus of claim 18, wherein the connection comprises a Radio Resource Control (RRC) connection between the user equipment and the non-terrestrial node.

20. The apparatus of any one of claims 15 to 19, wherein the instructions are further configured to cause the apparatus at least to:- receive, from the non-terrestrial node, a paging message using the binding information.

21. The apparatus of any one of claims 15 to 20, wherein the instructions are further configured to cause the apparatus at least to:- receive, from the non-terrestrial node, an Authentication and Key Agreement (AKA) challenge;- transmit, to the non-terrestrial node, a response to the AKA challenge; and- authenticate the user equipment to the network.

22. The apparatus of any one of claims 15 to 21, wherein the instructions are further configured to cause the apparatus at least to:- responsive to a link between the user equipment and the non-terrestrial node available via another non-terrestrial node acting as a relay node, receive, from the non-terrestrial node via the other non-terrestrial node, a paging message using the binding information.

23. The apparatus of claim 22, wherein the instructions are further configured to cause the apparatus at least to:- receive, from the non-terrestrial node via the other non-terrestrial node, the AKA challenge;- transmit, to the non-terrestrial node via the other non-terrestrial node, a response to theAKA challenge; and- authenticate the user equipment to the network.

24. The apparatus of any one of claims 15 to 23, wherein the binding information is to be used by the user equipment until the user equipment is authenticated to the network.

25. The apparatus of any one of claims 15 to 24, wherein the binding information comprises Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

26. A method performed by a non-terrestrial node in a network, comprising:- receiving, from a user equipment, a registration request;- responsive to a link between the non-terrestrial node and a terrestrial node of the network to forward the registration request not being available: storing the registration request; and assigning binding information associated with the non-terrestrial node to the user equipment; and- transmitting, to the user equipment, a message comprising the binding information to be used by the user equipment.

27. The method of claim 26, wherein the registration request comprises an identifier associated with the user equipment.

28. The method of claim 27, wherein the identifier comprises a Subscription Concealed Identifier (SUCI) of the user equipment.

29. The method of any one of claims 26 to 28, further comprising:- performing a procedure to establish a connection to the user equipment.

30. The method of claim 29, wherein the connection comprises a Radio Resource Control (RRC) connection between the user equipment and the non-terrestrial node.

31. The method of any of claims 26 to 30, further comprising:- responsive to the link being available, forwarding the registration request to the terrestrial node;- receiving, from the terrestrial node, an Authentication and Key Agreement (AKA) challenge; and- storing an association of the AKA challenge and the binding information.

32. The method of claim 31, wherein the association of the AKA challenge and the binding information is stored in a mapping table.

33. The method of claim 30 or 31, further comprising:- transmitting, to the user equipment, a paging message using the binding information.

34. The method of any one of claims 31 to 33, further comprising:- transmitting, to the user equipment, the AKA challenge;- receiving, from the user equipment, a response to the AKA challenge; and- authenticating the user equipment to the network.

35. The method of any one of claims 31 to 34, further comprising:- responsive to a link between the user equipment and the non-terrestrial node available via another non-terrestrial node acting as a relay node, transmitting, to the user equipment via the other non-terrestrial node, a paging message using the binding information.

36. The method of claim 35, further comprising:- transmitting, to the user equipment via the other non-terrestrial node, the AKA challenge;- receiving, from the user equipment via the other non-terrestrial node, a response to the AKA challenge; and- authenticating the user equipment to the network.

37. The method of any one of claims 26 to 36, wherein the binding information is to be used by the user equipment until the user equipment is authenticated to the network.

38. The method of any one of claims 26 to 37, wherein the binding information comprises Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

39. The method of any one of claims 26 to 38, wherein the non-terrestrial node is incorporated in a satellite.

40. A method performed by a user equipment in a network, comprising:- transmitting, to a non-terrestrial node, a registration request; and- receiving, from the non-terrestrial node, a message comprising binding information associated with the non-terrestrial node to be used by the user equipment, the binding information being assigned to the user equipment.

41. The method of claim 40, wherein the registration request comprises an identifier associated with the user equipment.

42. The method of claim 41, wherein the identifier comprises a Subscription Concealed Identifier (SUCI) of the user equipment.

43. The method of any one of claims 40 to 42, further comprising:- performing a procedure to establish a connection to the non-terrestrial node.

44. The method of claim 43, wherein the connection comprises a Radio Resource Control (RRC) connection between the user equipment and the non-terrestrial node.

45. The method of any one of claims 40 to 44, further comprising:- receiving, from the non-terrestrial node, a paging message using the binding information.

46. The method of any one of claims 40 to 44, further comprising:- receiving, from the non-terrestrial node, an Authentication and Key Agreement (AKA) challenge;- transmitting, to the non-terrestrial node, a response to the AKA challenge; and- authenticating the user equipment to the network.

47. The method of any one of claims 40 to 47, further comprising:- responsive to a link between the user equipment and the non-terrestrial node available via another non-terrestrial node acting as a relay node, receiving, from the non-terrestrial node via the other non-terrestrial node, a paging message using the binding information.

48. The method of claim 47, further comprising:- receiving, from the non-terrestrial node via the other non-terrestrial node, the AKA challenge;- transmitting, to the non-terrestrial node via the other non-terrestrial node, a response to the AKA challenge; and- authenticating the user equipment to the network.

49. The method of any one of claims 40 to 48, wherein the binding information is to be used by the user equipment until the user equipment is authenticated to the network.

50. The method of any one of claims 40 to 49, wherein the binding information comprises Radio Network Temporary Identifier (RNTI) associated with the non-terrestrial node.

51. A computer program product comprising program instructions stored on a computer readable medium to execute a method of any of claims 26 to 50 when said program is executed on a computer.

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