Control plane (C plane) signaling reduction for network operators with network sharing protocol

Abstract

A method includes receiving, by a first core network entity of a first core network, a registration request from a user equipment (UE), wherein the first core network is a core network of a first operator; assigning, by the first core network entity, a long-term UE context to the UE, the long-term UE context configured to be maintained by a second core network and configured to allow the UE to switch from communicating with the first core network to communicating with the second core network without re-registering with the second core network, where the second core network is a core network of a second operator, the second operator is different from the first operator; and transmitting a registration response to the UE in response to the registration request, the registration response including the long-term UE context assigned to the UE.

Description

Cross-reference to related applications

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 586,596, filed on September 29, 2023, which is incorporated herein by reference as if reproduced in its entirety. Technical Field

[0002] The various example embodiments generally relate to wireless networks, and more specifically to the reduction of control plane (C plane) signaling for network operators with network sharing protocols. Background Technology

[0003] Wireless networks offer significant advantages for user mobility. The ability to remain connected to wireless networks while on the move not only benefits the user but also contributes to greater efficiency and productivity for society as a whole. As users and / or operators have increasingly higher expectations regarding network sharing, network energy costs, and device battery life, wireless network technologies must keep pace. Therefore, there is a continued interest in improving wireless network technologies. Summary of the Invention

[0004] As used herein, the term “entity” can refer to different components of an architecture or device in a communications network, such as a network device, network node, network function, or any other device (physical or virtual).

[0005] According to an aspect of this disclosure, a method includes receiving a registration request from a user equipment (UE) by a first core network entity of a first core network, wherein the first core network is the core network of a first operator; allocating a long-term UE context to the UE by the first core network entity, the long-term UE context being configured to be maintained by a second core network and configured to allow the UE to switch from communicating with the first core network to communicating with the second core network without re-registering with the second core network, wherein the second core network is the core network of a second operator, which is different from the first operator; and sending a registration response to the UE in response to the registration request, the registration response including the long-term UE context allocated to the UE.

[0006] In one aspect of the method, the method further includes determining whether to provide a long-term UE context to the UE based on at least one of the following: the UE's mobility mode, the UE's quality of service (QoS), the UE's energy, the UE's geographic location, or the maximum number of long-term UE contexts for the UE based on a network sharing protocol between the first operator and the second operator.

[0007] In one aspect of the method, the method further includes selecting an identifier for a long-term UE context from a long-term UE context identifier pool by a first core network entity, wherein the long-term UE context identifier pool is provided based on a network sharing protocol between a first operator and a second operator.

[0008] In one aspect of the method, the long-term UE context assigned to the UE includes at least one of the following: an identifier of the long-term UE context, registration update timer information, information associated with a bearer configured for the UE, information associated with a service configured for the UE, information associated with the UE's registration area, information associated with the UE's reachability configuration, or information associated with the UE's security configuration, or information associated with one or more of the UE's capabilities.

[0009] In one aspect of this method, the first core network is part of the UE's home network, and the second core network is part of the UE's roaming network.

[0010] In one aspect of the method, the method further includes offloading the UE's communications to a second core network by a first core network entity.

[0011] In one aspect of the method, the method also includes transitioning from the first core network entity to an energy efficiency state.

[0012] In one aspect of the method, the method further includes receiving from the UE a first core network entity an indication from the UE of the revocation of a long-term UE context by a second core network; and deleting the long-term UE context of the UE in response to receiving the indication of revocation of the long-term UE context.

[0013] In one aspect of the method, the method further includes allocating a second long-term UE context to the UE by a first core network entity, the second long-term UE context being configured to be maintained by the first core network entity and configured to allow the UE to switch communication from the second core network to the first core network without re-registering with the first core network.

[0014] In one aspect of the method, the method also includes maintaining a registration update timer associated with the second long-term UE context.

[0015] According to an aspect of this disclosure, a method includes receiving a long-term registration request from a user equipment (UE) by a first core network entity of a first core network, the long-term registration request including the UE's long-term UE context, wherein the first core network is the core network of a first operator; and in response to the long-term registration request, sending registration update timer information to the UE, the registration update timer information being configured to be maintained by the UE and configured to allow the UE to switch from communicating with a second core network to communicating with the first core network without re-registering with the first core network, wherein the second core network is the core network of a second operator, which is different from the first operator.

[0016] In one aspect of this method, the first core network is part of the UE's roaming network, and the second core network is part of the UE's home network.

[0017] In one aspect of the method, at least one of the UE's long-term UE context or registration update timer information is provided based on a network sharing protocol between the first operator and the second operator.

[0018] In one aspect of the method, the long-term UE context includes at least one of the following: an identifier for the long-term UE context, information associated with a bearer configured for the UE, information associated with a service configured for the UE, information associated with the UE's registration region, information associated with the UE's reachability configuration, information associated with the UE's security configuration, or information associated with one or more of the UE's capabilities.

[0019] In one aspect of the method, the method also includes an identifier for authenticating a long-term UE context.

[0020] In one aspect of the method, the method further includes maintaining a long-term UE context for the UE at a first core network; and using the maintained long-term UE context for the UE when the UE switches from a second core network to the first core network.

[0021] In one aspect of the method, the method further includes revoking the long-term UE context of the UE by a first core network entity based on at least one of the UE's mobility mode or a network sharing agreement between the first operator and the second operator.

[0022] In one aspect of the method, the method further includes sending an indication from a first core network entity to the UE that the UE's long-term UE context has been revoked.

[0023] According to an aspect of this disclosure, a method includes receiving a long-term UE context associated with a first core network and assigned to the UE, the long-term UE context being configured to enable the UE to switch from communicating with a second core network of a second operator to communicating with the first core network without re-registering with the first core network, wherein the first core network is the core network of the first operator, and wherein the second core network is the core network of a second operator different from the first operator; and the UE switching communication with the second core network to communication with the first core network, wherein communication with the first core network is based on the long-term UE context.

[0024] In one aspect of the method, one of the first core network or the second core network is part of the UE's home network, and the other of the first core network or the second core network is part of the UE's roaming network.

[0025] In one aspect of the method, the method further includes: when the UE communicates with the second core network, the UE maintains a long-term UE context associated with the first core network.

[0026] In one aspect of the method, the long-term UE context includes at least one of the following: an identifier for the long-term UE context, registration update timer information, information associated with a bearer configured for the UE, information associated with a service configured for the UE, information associated with the UE's registration region, information associated with the UE's reachability configuration, information associated with the UE's security configuration, or information associated with one or more of the UE's capabilities.

[0027] In one aspect of the method, the method further includes the UE sending a registration request to the second core network to register with the second core network, wherein receiving the long-term UE context includes: in response to the registration request, receiving a registration response including the long-term UE context from the second core network.

[0028] In one aspect of the method, the method further includes the UE sending a long-term registration request to a first core network, the long-term registration request including a long-term UE context, and in response to the long-term registration request, the UE receiving information associated with a registration update timer from the first core network.

[0029] In one aspect of the method, the method further includes: based on the long-term UE context and based on the ongoing registration update timer associated with the first core network, the UE camps on the first core network without re-registering with the first core network.

[0030] In one aspect of the method, the method further includes the UE sending a registration request to the first core network to register with the first core network, wherein receiving the long-term UE context includes: in response to the registration request, the UE receiving a registration response including the long-term UE context from the first core network.

[0031] In one aspect of the method, the method further includes the UE receiving an indication from the first core network that a long-term UE context associated with the first core network has been revoked; and in response to the indication that the long-term UE context associated with the first core network has been revoked, the UE releasing the long-term UE context.

[0032] In one aspect of the method, the method further includes the UE sending a notification to the second core network to notify the second core network that the long-term UE context associated with the first core network has been revoked.

[0033] In one aspect of the method, switching to communication with the first core network responds to an energy efficiency state transition associated with the second core network.

[0034] The independent claims provide the subject matter for several aspects. The dependent claims define several other aspects. Attached Figure Description

[0035] Some exemplary embodiments will now be described with reference to the accompanying drawings.

[0036] Figures 1A-1D These are illustrations of example embodiments of various configurations of a wireless communication system according to an aspect of this disclosure;

[0037] Figure 2 This is a diagram of an example wireless communication system according to one aspect of this disclosure;

[0038] Figure 3 This is a diagram illustrating an example of signals and operation of a network system for supply network sharing, based on one aspect of this disclosure;

[0039] Figure 4A and Figure 4B This is a diagram illustrating control plane signaling (e.g., messages) transmitted between the UE, home network, and roaming network according to one aspect of this disclosure, as well as operations performed by the user equipment, home network, and roaming network.

[0040] Figure 5 This is a flowchart illustrating an example operation of a UE (user-to-user) roaming between networks according to one aspect of this disclosure.

[0041] Figure 6 This is a flowchart illustrating an example operation of a UE migrating between networks according to one aspect of this disclosure;

[0042] Figure 7 This is a flowchart illustrating an example operation of a network device that provides a long-term UE context to a UE according to one aspect of this disclosure;

[0043] Figure 8 This is a flowchart illustrating an example operation of a network device performing long-term registration with a UE according to one aspect of this disclosure;

[0044] Figure 9 This is a flowchart illustrating an example operation of a UE migrating between networks according to one aspect of this disclosure; and

[0045] Figure 10 This is a diagram illustrating an example embodiment of a component of a UE or network device according to one aspect of this disclosure. Detailed Implementation

[0046] In the following description, certain specific details are set forth in order to provide a thorough understanding of the disclosed aspects. However, those skilled in the art will recognize that the aspects can be practiced without one or more of these specific details or using other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers are not shown or described in detail to avoid unnecessarily obscuring the description of the aspects.

[0047] In this specification, references to "an aspect" or "one aspect" indicate that a particular feature, structure, or characteristic described in conjunction with that aspect is included in at least one aspect. Therefore, the appearance of the phrase "in an aspect" or "in one aspect" in various places in this specification does not necessarily refer to the same aspect. Furthermore, a particular feature, structure, or characteristic may be combined in any suitable manner with one or more aspects.

[0048] This disclosure generally relates to wireless networks that implement technologies such as, but not limited to, Global Microwave Access Interoperability (WiMAX), Global System for Mobile Communications (GSM, 2G), GSM EDGE Radio Access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunications System based on Basic Wideband Code Division Multiple Access (W-CDMA) (UMTS, 3G), High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), Advanced LTE, Enhanced LTE (eLTE), 5G New Radio (5G NR), Advanced 5G, 6G (and higher) technologies. The term 'eLTE' here refers to LTE evolution that connects an LTE radio access network to a 5G core network. LTE is also known as evolved UMTS.

[0049] Network sharing enables operators to maximize deployment and improve overall network quality. Various types of network sharing frameworks and / or configurations exist. Two commonly used network sharing frameworks in industry are Multi-Operator Radio Access Network (MORAN) and Multi-Operator Core Network (MOCN). In the MORAN framework, a radio access network (RAN) is deployed where all radio components of the RAN (e.g., antennas, base stations, towers, sites, and power supplies) are shared by two or more operators; however, the RAN's radio carriers are not shared. On the other hand, in the MOCN framework, two or more core networks operating separately (or independently) sharing a common core network infrastructure can share the same RAN, including radio carriers. The MOCN framework can be efficient for network sharing because it allows mobile operators to pool (share) their respective spectrum allocations, thereby improving relay efficiency.

[0050] As the deployment of 5G-enabled wireless networks (e.g., 5G wireless networks) expands, more network sharing scenarios may emerge, depending on operator strategies, commercial agreements between operators, and specific rules and / or legislation in certain countries. One challenge faced by operators participating in network sharing (e.g., operators sharing a network) is maintaining the interconnection (e.g., the number of network interfaces) between the shared RAN (e.g., Next-Generation Radio Access Network (NG-RAN)) and the core networks of the respective participating operators (e.g., the core networks of each participating operator), especially when a large number of base stations are shared among the participating operators. Therefore, other network sharing scenarios may need to be considered, in which the RAN can be shared among multiple operators without each operator's core network having a direct connection to the shared RAN.

[0051] Network sharing can benefit a variety of network deployment scenarios. In one example, network sharing can enable industries to achieve sustainability goals (e.g., reducing network power consumption). For instance, when multiple operators have overlapping coverage areas, one or more operators can shut down portions of their networks in a particular area during certain times of the day when data traffic in one or more operators' networks may be low. Users of the network(s) with portions of their networks shut down can then be served by the remaining active networks(s). In this way, operators can reduce the number of active base stations transmitting during low-traffic periods, thereby reducing network power consumption.

[0052] For example, an operator may wish to shut down (or power off) portions of its network during periods of low traffic and may require its subscribers (e.g., subscribers' UEs) to use another operator's network. To facilitate the offloading of subscribers' UEs to (multiple) other networks, the operator and (multiple) other operators may have network sharing agreements, specifying the time and / or duration during which the offloading of UEs may occur. During the agreed-upon sharing period, the operator of the subscriber's home network (e.g., Home Public Land Mobile Network (HPLMN)) may then shut down (multiple) its base stations and / or other network resources, and the subscriber's UE may roam to one of (multiple) other networks of another operator with which a network sharing agreement has been entered into. While roaming, the UE may register with the roaming network (e.g., another operator's network). The subscriber's UE may switch back to (return to) its HPLMMN (e.g., at the end of the network sharing period), where switching back to (return to) the HPLMMN may include re-registering with the HPLMMN. Typically, when a UE switches from one network to another (e.g., a new network), the UE must perform a registration process with the new network or, more specifically, with the core network of the new network.

[0053] As used herein, the term "home network" can refer to the network to which the UE's subscriber is subscribed (e.g., the UE's HPLMN). For example, the UE may have a Subscriber Identity Module (SIM) configured according to the subscription. As used herein, the term "home core network" can refer to the core network of the home network. For example, a subscribed UE may register with the home core network to access services(s) provided by the home core network. As used herein, the term "roaming network" can refer to the network operated by a roaming partner of the operator operating the home network (e.g., accessing a Public Land Mobile Network (VPLMN)). As used herein, the term "roaming core network" can refer to the core network of the roaming network. For example, a UE may register with the roaming core network to access services(s) provided by the roaming core network.

[0054] Migrating subscribers (e.g., UEs) from one network to another during low-traffic periods allows operators to shut down portions of their networks (e.g., base stations) to conserve energy. However, the number of subscribers needing to migrate to the roaming core network can be very high (e.g., 100, 200, 500, or more). Therefore, it may be necessary to optimize control plane procedures (e.g., registration procedures) to migrate subscribers between different operators' networks in network sharing protocols. In one example, during low-traffic periods, most of a subscriber's UEs may be in idle mode. Therefore, generating control plane messages to migrate from the home network to another network and then returning to the home network (e.g., registration request messages) may not be efficient for the subscriber's UEs, as generating such messages consumes the subscriber's UE power and uses network resources. Furthermore, high C-plane load may limit the frequency with which the home core network migrates subscribers' UEs to another network, thereby reducing the home network's energy consumption.

[0055] This disclosure provides techniques for reducing control plane signaling when two or more operators share networks, by allowing a UE to migrate between core networks (e.g., the home core network of the UE's HPLMN operator and the roaming core network of another PLMN operator) without re-registering each time the UE enters one core network (e.g., with reduced or lower mobility). The home core network and the roaming core network are separate core networks. In some cases, the HPLMN operator and other PLMN operators may have their own RAN (with partially overlapping or non-overlapping coverage areas). In other cases, the HPLMN operator and other PLMN operators may share the same RAN (e.g., in the MORAN configuration described above). In one aspect of this disclosure, to enable a UE to dynamically migrate between a first core network (e.g., one operator's core network) and a second core network (e.g., another operator's core network) without re-registering to a first core network and / or a second core network, the first core network may assign a long-term UE context for use in the first core network and / or a long-term UE context for use in the second core network, respectively.

[0056] As used herein, the term "long-term UE context" can refer to a UE context that is stored long-term at the core network and the UE. Long-term storage of a UE context means that the core network stores the UE context for a longer period than the normal period. For example, the core network typically stores the context of a UE (with normal registration in the core network) only while the UE is in the core network, but releases or deletes the UE context when the UE leaves (or deregisters) the core network. That is, the normal period for storing the UE context is from the time the UE registers with the core network to the time the UE leaves the core network. In contrast, in this disclosure, the core network can maintain, store, save, or retain the long-term UE context of a UE (with long-term registration in the core network) not only while the UE is in the core network, but also after the UE switches to another core network. Similarly, for a UE with long-term registration with the core network, the long-term UE context of the UE can be maintained, stored, saved, or retained in association with the core network not only while the UE is in the core network, but also after the UE switches to another core network. Because the long-term UE context will be maintained at the core network and / or the UE for an extended period (e.g., longer than the normal period), the long-term UE context can also be referred to as an extended UE context.

[0057] The terms “long-term UE context information” and “long-term registration information” can refer to information associated with a long-term UE context and can be used interchangeably in this document. Therefore, a description that references one of these terms should be regarded as a description that also references the other term.

[0058] According to one aspect of the invention, a first core network entity of a first core network can receive a registration request from a UE for registering with the first core network. The first core network may be the core network of a first operator. In one example, the first core network entity may be the Access and Mobility Function (AMF) of the first core network. The first core network may assign a long-term UE context to the UE. The long-term UE context may be configured to be maintained by a second core network and configured to allow the UE to switch from communicating with the first core network to communicating with the second core network without re-registering with the second core network. The second core network may be the core network of a second operator different from the first operator. In response to the registration request, the first core network entity may send a registration response to the UE including information associated with the long-term UE context assigned to the UE. In some aspects, the first core network may be part of the UE's home network, and the second core network may be part of the UE's roaming network.

[0059] In some aspects, the first core network entity may determine whether to assign a long-term UE context to a UE based on at least one of the following: the UE's mobility pattern, the UE's Quality of Service (QoS), the UE's energy, the UE's geographic location, or a network sharing agreement between the first and second operators. For mobility pattern, the assignment may be based on the UE's past history, indicating that the UE registered with the same cell in the first core network during the last certain number of transitions (e.g., 2, 3, 5, 6, 10, or more transitions) to and from the second core network. That is, the UE may have low mobility. Alternatively, the assignment may be based on the UE's predicted mobility pattern being a low mobility pattern. For QoS, the assignment may be based on the first core network entity determining to minimize the UE's downtime (e.g., because the UE is a high-priority UE). Alternatively, the assignment may be based on the UE's downtime requirements (e.g., a high QoS subscription). For energy, the assignment may be based on the UE having unlimited energy resources (e.g., when the UE is plugged in to charge, this can also serve as an indirect indicator of low mobility). Regarding geographic location, this allocation can be based on the UE's geographic location, for example, within the registration area of ​​the home network to which the network protocol may be applied. In some aspects, the network protocol may include a maximum or threshold number of UE contexts that can be stored long-term by the second core network, and / or information to be used by the UE to request long-term registration with the second core network (e.g., long-term UE context identifier).

[0060] In some respects, the first core network entity can select identifiers for long-term UE contexts from a long-term UE context identifier pool. The first core network entity can configure the long-term UE context pool based on the network sharing protocol between the first operator and the second operator.

[0061] In some aspects, the long-term UE context information provided to the UE may include at least one of the following: an identifier associated with the long-term UE context (e.g., a long-term UE context identifier), registration update timer information, information associated with a bearer configured for the UE (e.g., associated with multiple Protocol Data Unit (PDU) sessions), information associated with a service configured for the UE (e.g., associated with multiple PDU sessions), information associated with the UE's registration area (e.g., tracking area information), information associated with the UE's reachability configuration (e.g., paging capabilities and / or parameters), information associated with the UE's security configuration (e.g., parameters associated with encryption and / or integrity protection), or information associated with one or more of the UE's capabilities.

[0062] The UE can move between a first core network and a second core network. In some aspects, during the initial registration with the second core network, the UE can send a long-term registration request to the second core network (e.g., a core network entity of the second core network, such as an AMF). The long-term registration request may include a long-term UE context assigned to the UE by the first core network entity. In response, the second core network may send registration update timer information to the UE. The registration update timer information can be configured to be maintained by the UE and configured to allow the UE to switch from communicating with the first core network to communicating with the second core network without re-registering with the second core network. In some cases, the registration update timer information may include an indication of the registration update timer duration (time length), which can be used by the UE to configure periodic registration update timers (e.g., for the UE to update its mobility information to the second core network). In some cases, the registration update timer information may be based on a network protocol.

[0063] In some respects, the first core network can offload the UE to the second core network. For example, the first core network can transition to an energy efficiency state, and offloading can be triggered by a state transition. In some cases, the UE can return to the first core network when the first core network transitions out of the energy efficiency state. Typically, the UE can switch back and forth between communicating with the first core network and communicating with the second core network based on certain conditions. During each switch to communicating with the second core network, the UE (with a long-term registration with the second core network) does not need to re-register with the second core network if: (1) the registration update timer configured at the UE according to the registration update timer information is running (e.g., in progress or active), and (2) the UE is in the same registration area as when the UE last registered with the second core network. In some respects, after the UE leaves the second core network, the second core network can continue to maintain, save, retain, and / or store the long-term UE context associated with the UE. When the UE re-enters the second core network, the second core network can use the maintained long-term UE context to communicate with the UE. In some respects, the UE can continue to maintain, save, retain, and / or store the long-term UE context associated with the second core network after leaving the second core network. When the UE re-enters the second core network, the UE can use the maintained long-term UE context to communicate with the second core network.

[0064] In some aspects, the second core network entity of the second core network can determine whether to revoke or cancel the long-term registration of a UE based on the UE's mobility pattern (e.g., excessive mobility) or at least one of the network sharing protocols (e.g., a protocol violation or abnormal violation of network protocols detected by the second core network). In one example, the second core network entity can determine that the number of active long-term UE contexts stored at the second core network is greater than a threshold number of long-term UE contexts agreed upon in the network sharing protocol. After revoking the long-term registration, the second core network entity can delete the UE's long-term UE context. In some aspects, when the UE returns to the first core network, the UE can notify the first core network entity that the long-term registration or long-term UE context has been revoked by the second core network. In response, the first core network entity can delete the long-term UE context assigned to the UE.

[0065] In some respects, the first core network entity may assign another long-term UE context (e.g., a second long-term UE context) to the UE. The second long-term UE context may be configured to be maintained by the first core network entity and configured to allow a subscriber's UE to roam from a second network to the first network without re-registering with the first core network. The first core network entity may maintain a registration update timer associated with the second long-term UE context. These and other aspects will be described in more detail later in this document.

[0066] The aspects of this disclosure offer various advantages. For example, assigning a long-term UE context associated with both the roaming and home core networks to a low-mobility UE allows the UE to migrate between the roaming and home core networks without re-registration. This can significantly reduce C-plane load (e.g., signaling) in both the home and roaming core networks. Furthermore, battery consumption at the low-mobility UE, power consumption at the roaming core network, and / or power consumption at the home core network can be reduced. Additionally, the reduced C-plane load can allow network sharing outside of low-traffic periods, for example, to provide capacity increases or load balancing. While this disclosure is described in the context of optimizing C-plane traffic and / or operation in network sharing between the home and roaming networks, the mechanisms described herein can be used for network sharing between any suitable core networks (e.g., between two roaming core networks).

[0067] This disclosure may use the term "serving network device" to refer to a network node or network device (or part thereof) serving a UE. As used herein, the terms "send to," "receive from," and "cooperate with" (and variations thereof) include communication that may or may not involve communication via one or more intermediate devices or nodes. The term "acquire" (and variations thereof) includes initial acquisition or reacquisition after initial acquisition. The term "connection" may refer to a physical connection or a logical connection.

[0068] This disclosure uses 5G NR as an example of a wireless network, and may use smartphones and / or extended reality headsets as examples of UEs. It is intended and should be understood that such examples are merely illustrative, and this disclosure applies to other wireless networks and user equipment.

[0069] Figures 1A-1D This is a diagram illustrating various configurations of a wireless communication system according to an aspect of this disclosure. Figure 1A The illustration shows a sample MORAN configuration. Figure 1B The illustration shows a sample MOCN configuration. Figures 1C-1D The illustration shows an example configuration of the home network operator and roaming network operator (for the UE's subscriber), each with its own core network and its own RAN. Figure 1C In this context, the coverage areas of the residential communities belonging to the network operator and the roaming network operator do not overlap. On the other hand, in... Figure 1D In China, the coverage areas of the residential communities belonging to the network operator and the roaming network operator partially overlap.

[0070] A wireless communication system (e.g., a 5G system) may include a core network, one or more RANs, and one or more UEs. The RAN may include one or more network nodes, which may be referred to as RAN nodes. At higher layers, the RAN can provide radio interfaces and manage radio resources for radio communication with one or more UEs, and can communicate with the corresponding core network. The core network may include one or more network servers and / or network devices and / or software for implementing various network functions. At higher layers, the core network can communicate with the RAN, process user data of UEs (served by the RAN) communicating with the RAN, and manage UE access and mobility.

[0071] As used herein, the term "network device" can refer to any component of the RAN or core network in a wireless communication system. Examples of network devices include, but are not limited to, devices for implementing various aspects of 5G NR. This disclosure describes embodiments related to 5G NR and embodiments relating to aspects defined by the 3rd Generation Partnership Project (3GPP). However, it is contemplated that embodiments related to other wireless network technologies are also covered within the scope of this disclosure.

[0072] The following description provides further details of an example of a RAN node. In a 5G NR network, a gNodeB (also known as a gNB) may include, for example, a node that provides NR user plane and control plane protocol termination toward the UE and is connected to the 5G core (5GC) via an NG interface, such as according to Section 3.2 of 3GPP TS 38.300 V16.6.0 (2021-06) (the entire contents of which are incorporated herein by reference).

[0073] gNB supports various protocol layers, such as Layer 1 (L1) (i.e., the physical layer), Layer 2 (L2), and Layer 3 (L3).

[0074] NR's Layer 2 (L2) is divided into the following sublayers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptation Protocol (SDAP), among which: ○ The physical layer provides a transmission channel to the MAC sublayer; ○ The MAC sublayer provides logical channels to the RLC sublayer; ○ The RLC sublayer provides RLC channels to the PDCP sublayer; ○ The PDCP sublayer provides radio bearers to the SDAP sublayer; ○ The SDAP sublayer provides Quality of Service (QoS) flows to 5GC; ○ The control channels include the Broadcast Control Channel (BCCH) and the Physical Control Channel (PCCH).

[0075] Layer 3 (L3) includes, for example, Radio Resource Control (RRC) conforming to Section 6 of 3GPP TS 38.300 V16.6.0 (2021-06) (the entire contents of which are incorporated herein by reference).

[0076] The gNB Central Unit (gNB-CU) includes, for example, a logical node that hosts, for example, the gNB's Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols, or the en-gNB's RRC and PDCP protocols. This logical node controls the operation of one or more gNB Distributed Units (gNB-DUs). The gNB-CU terminates the F1 interface connected to the gNB-DU. The gNB-CU may also be referred to herein as a CU, Central Unit, Centralized Unit, or Control Unit.

[0077] A gNB Distributed Unit (gNB-DU) includes, for example, a logical node that hosts the Radio Link Control (RLC), Media Access Control (MAC), and Physical (PHY) layers of the gNB or en-gNB, and its operation is partially controlled by the gNB-CU. A gNB-DU supports one or more cells. A cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface connected to the gNB-CU. The gNB-DU may also be referred to herein as a DU or Distributed Unit.

[0078] As used herein, the terms "network node" or "RAN node" may refer to any gNB, gNB-CU, or gNB-DU, or any combination thereof. RAN (Radio Access Network) nodes or network nodes (such as, for example, gNB, gNB-CU, or gNB-DU, or portions thereof) may be implemented using means, for example, having at least one processor and / or at least one memory having processor-readable instructions ("program") configured to support and / or supply and / or process CU and / or DU related functions and / or features, and / or at least one protocol (sub) layer of the RAN (Radio Access Network), such as Layer 2 and / or Layer 3. Different functional divisions may exist between central units and distributed units. The following will combine... Figure 10 Examples describing such devices and components.

[0079] The gNB-CU and gNB-DU portions can be, for example, co-located or physically separated. The gNB-DU can even be further divided into two parts, for example, one part including processing equipment and the other including an antenna. The Central Unit (CU) can also be referred to as a Baseband Unit / Radio Equipment Controller / Cloud RAN / Virtual RAN (BBU / REC / C-RAN / V-RAN), Open RAN (O-RAN), or a portion thereof. The Distributed Unit (DU) can also be referred to as a Remote Radio Headend / Remote Radio Unit / Radio Equipment / Radio Unit (RRH / RRU / RE / RU), or a portion thereof. In the various exemplary embodiments of this disclosure below, a network node supporting at least one of the Central Unit functions or Layer 3 protocols of a radio access network can be, for example, a gNB-CU. Similarly, a network node supporting at least one of the Distributed Unit functions or Layer 2 protocols of a radio access network can also be, for example, a gNB-DU.

[0080] A gNB-CU can support one or more gNB-DUs. A gNB-DU can support one or more cells, and therefore can support the serving cell of a user equipment (UE), or a candidate cell for procedures such as handover, dual connectivity, and / or carrier aggregation.

[0081] The UE can be or includes wireless or mobile devices, devices having a radio interface for interacting with the RAN (Radio Access Network), smartphones, in-vehicle devices, Internet of Things (IoT) devices, or M2M devices, and other types of user equipment. Such a UE may include: at least one processor; and at least one memory including program code; wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the device to perform at least certain operations, such as, for example, an RRC connection with the RAN. Examples of UE components will be combined. Figure 10The following description is provided. In an embodiment, the UE may be configured to generate a message (e.g., including a cell ID) to be transmitted to the RAN via radio (e.g., to reach and communicate with the serving cell). In an embodiment, the UE may generate, transmit, and receive RRC messages containing one or more RRC PDUs (Packet Data Units). Those skilled in the art will understand the RRC protocol and other processes that the UE may perform.

[0082] In an example of a 5G NR network, the RAN provides one or more cells that define the coverage area of ​​the RAN. As described above, the RAN may include a gNB of the 5G NR network, or may include any other means configured to control radio communications and manage radio resources within the cells. As used herein, the term "resource" may refer to radio resources such as resource blocks (RBs), physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency regions, subcarriers, beams, etc. In embodiments, network nodes may be referred to as base stations.

[0083] refer to Figure 1A Operator A's core network 110 and Operator B's core network 112 can communicate with the UEs of their respective operators' subscribers in the MORAN configuration using a shared RAN (e.g., including common RAN node 120). The following will refer to... Figure 2 A more comprehensive discussion of core networks 110 and 112 follows. RAN node 120 can be a gNB as described above. As mentioned above, in a MORAN configuration, multiple operators can share the same RAN, but the RAN's radio carriers are not shared by the operators. Figure 1A In the example shown, subscriber UE 150 subscribes to operator A, subscriber UE 152 subscribes to operator B, and RAN node 120 communicates with UE 150 of operator A using frequency F1 (e.g., a radio carrier frequency) and with UE 152 of operator B using frequency F2 (e.g., a radio carrier frequency), where F1 and F2 are different frequencies. Figure 1A As further shown, RAN node 120 can provide coverage area 130 using frequency F1 and coverage area 131 using frequency F2, wherein coverage areas 130 and 131 can be independent of each other. UE 150 and UE 152 can be as described above.

[0084] refer to Figure 1B Operator A's core network 110 and Operator B's core network 112 can communicate with the UEs of their respective operators' subscribers using the MOCN configuration via a shared RAN (e.g., including a common RAN node 122). RAN node 122 can be a gNB as described above. As mentioned above, in the MOCN configuration, multiple operators can share the same RAN, including radio carriers. Figure 1B In the example shown, UE 150's subscriber subscribes to operator A, UE 152's subscriber subscribes to operator B, and RAN node 122 communicates with both UE 150 of operator A and UE 152 of operator B using the same frequency F3 (e.g., radio carrier frequency). Figure 1A As further shown, RAN node 122 can provide coverage area 132.

[0085] refer to Figure 1C A subscriber to UE 150 can subscribe to the operator of the operating core network 114 (e.g., operator A) and the corresponding RAN (e.g., including RAN node 124) providing coverage area 133 (e.g., using frequency F4). The core network 114 can be referred to as the home core network 114 of UE 150. Furthermore, the home core network 114 and the corresponding RAN (including RAN node 124) can be referred to as the home network of UE 150.

[0086] like Figure 1C As indicated by arrow 160, at time t1, UE 150 can travel from coverage area 133 to coverage area 134 operated by a different operator (e.g., Operator B), where coverage area 134 does not overlap with coverage area 133. In other words, UE 150 can roam to Operator B's network. Operator B can operate core network 116 and the corresponding RAN (e.g., including RAN node 126) providing coverage area 133 (e.g., using frequency F5). Core network 116 can be referred to as roaming core network 116. Furthermore, roaming core network 116 and the corresponding RAN (including RAN node 126) can be referred to as UE 150's roaming network. References will follow below. Figure 2 Let's discuss core networks 114 and 116 in more detail. Each of RAN nodes 124 and 126 can be a gNB as described above.

[0087] like Figure 1C As further illustrated by arrow 162, at time t2, a subscriber of UE 150 can roam back to its home network from the roaming network. In some cases, UE 150 can move back and forth between the home network and the roaming network. In one example, UE 150 can leave its home network (e.g., in area 133) and enter the roaming network (e.g., in area 134) during the day (e.g., at time t1), and can return (move backward) to its home network at night (e.g., at time t2).

[0088] refer to Figure 1D , Figure 1D The wireless communication system configuration shown is as follows Figure 1CThe wireless communication system configurations are basically similar. However, the home network operator A may have a coverage area 135 that partially overlaps with the coverage area 136 of the roaming network operator B. In one example, the home network operator A may determine to shut down a portion of its network (e.g., RAN node 124) during a specific time period to save energy, and may offload UE 150 to the roaming network during that period (i.e., UE 150 may be served by RAN node 126 and the roaming core network 112 of roaming network operator B).

[0089] Figures 1A-1D Examples are provided and are intended only to illustrate the configuration of a wireless communication system. Those skilled in the art will understand that... Figures 1A-1D The wireless communication system shown includes Figures 1A-1D Components not shown in the diagram, and it will be understood that other user equipment can communicate with each corresponding RAN node.

[0090] Figure 2 This is a block diagram of an example wireless communication system. A 5G NR network can be described as... Figure 2 The examples shown are of wireless communication systems, and the aspects described below should also apply to other types of network systems. Wireless communication systems may include a user plane and a control plane as shown and described herein. At higher layers, the user plane carries user traffic, while the control plane carries signaling traffic.

[0091] The following describes example functionality of the user plane and control plane components. The example functionality of the user plane and control plane components is illustrative only, and it should be understood that the components described herein can perform other operations.

[0092] The wireless communication system includes a core network and a RAN 225. The core network may include various core network functions. For example, the core network includes Authentication Server Function (AUSF) 211, AMF 212, and Session Management Function (SMF) 213. The core network also includes Network Slice Selection Function (NSSF) 214, Network Exposure Function (NEF) 215, Network Repository Function (NRF) 216, and UDM 217, whereby the UDM may include a UDR 224.

[0093] Additional network functions of the core network include Trusted Application Function (AF) 218 ​​and Policy Control Function (PCF) 219.

[0094] AUSF 211, AMF 212, SMF 213, NSSF 214, NEF 215, NRF 216, UDR 224, UDM 217, AF 218, and PCF 219 are part of the control plane of a wireless communication system. The core network also includes User Plane Functions (UPF) 226 in the user plane.

[0095] UE 150 can connect to data network (DN) 227 via the radio access network node of RAN 225, UPF 226, and the N6 interface of the core network. RAN 225 may include a combination of Figures 1A-1D The RAN 225 may be described as having one or more components, such as one or more radio network nodes. However, the RAN 225 may not be limited to such components. The UPF 226 provides connectivity for data transmitted between the radio access nodes of the RAN 225 and the UE 150 via the DN 227. The DN 227 is used to provide services from service providers, such as third-party service providers.

[0096] AMF 212 is configured to perform connectivity and mobility management tasks. In some cases, the core network may include multiple sets of AMF 212s, where an AMF 216 set can serve a specific area and multiple specific network slices. AUSF 211 receives authentication requests from AMF 212 and interacts with UDM 217 to authenticate and verify network responses to determine successful authentication. SMF 213 performs PDU session management and manages the session context with UPF 226.

[0097] NSSF 214 can select a Network Slice Instance (NSI) to serve UE 150 and determine the Network Slice Selection Auxiliary Information (NSSAI) for the Network Slice Instance. NSSF 214 can determine the AMF 212 or AMF 212 set that can be provided to UE 150 for the selected NSI. NEF 215 ensures third-party access to network services to create specialized network services. NRF 216 acts as a repository to store profiles of network functions to allow network functions to discover each other.

[0098] UDM 217 generates authentication vectors for use by AUSF 211 and AMF 212 and provides user identity processing. UDM 217 can connect to UDR 224, which stores data associated with authentication, applications, etc. AF 218 provides application services (e.g., streaming services) to users. PCF 219 provides policy control functions. For example, PCF 219 can assist with network slicing and mobility management, and provide Quality of Service (QoS) and accounting functions. In some cases, UDM 217 and / or UDR 224 can be referred to as network data components.

[0099] In one respect, Figures 1A-1B Each and / or in core networks 110 and 112 Figures 1C-1DEach of the core networks 114 and 116 can be similar to the core networks described above. For example, each of the core networks 110, 112, 114 and 116 can include AUSF, AMF, SMF, NSSF, NEF, NRF, UDR, UDM, AF 218, PCF and UPF, which are similar to AUSF 211, AMF 212, SMF 213, NSSF 214, NEF 215, NRF 216, UDR 224, UDM 217, AF 218, PCF 219 and UPF 226, respectively.

[0100] Figure 2 These are merely examples of components of a network system, and variations are considered to be within the scope of this disclosure. In embodiments, the network system may include... Figure 2 Other components not shown in the diagram. In embodiments, the network system may not include... Figure 2 Each component is shown. In an embodiment, components and connections can be used with... Figure 2 The connections shown are implemented using different connections. Such and other embodiments are considered to be within the scope of this disclosure.

[0101] Figure 3 This is a diagram illustrating an example operation of a network system for sharing a supply network according to one aspect of this disclosure. The following paragraphs will describe various signals and operations. It should be understood that a described signal may have an associated operation, and a described operation may have an associated signal. Therefore, a described signal can also be an operation, and a described operation can also be a signal. Furthermore, Figure 3 This will describe the signals between various network components and the operations performed by them, such as Figure 3 The components shown at the top. Specifically, these components include UE 302, home network 304, and roaming network 306. In one aspect, UE 302 may correspond to... Figures 1A-1D UE 150, and each of the home network 304 and the roaming network 306 can have as referenced above. Figure 2 The entities described (e.g., access nodes of the access network and network functions of the core network). Network components are illustrative, and it is conceivable that other components may participate in signaling or perform operations. In some examples, each of UE 302, home network 304, and roaming network 306 may use components with, for example... Figure 10 The apparatus of the components shown implements these operations. In some examples, the operation of the home network 304 may be implemented by the core network entity (e.g., AMF 212) at the home network 304. Similarly, the operation of the roaming network 306 may be implemented by the core network entity (e.g., AMF 212) at the roaming network 306. One or more of the following operations may be implemented in conjunction with the operations of this disclosure, as referenced above. Figure 2 Examples of discussion.

[0102] At operation 310, UE 302 registers with home network 304. The user of UE 302 can be a subscriber of home network 304. UE 302 can send, and home network 304 can receive, a registration request for registration with home network 304. In response, home network 304 can send, and UE 302 can receive, a registration response (e.g., a registration acceptance message). In some cases, after completing registration with home network 304, UE 302 can operate in idle mode and reside on home network 304.

[0103] At operation 312, UE 302 determines that it wants to camp on roaming network 306. In some cases, the determination to camp on roaming network 306 may be based on the detection or indication that home network 304 is transitioning to a specific state (e.g., an energy efficiency state, during which home network 304 may shut down certain network resources associated with home network 304 due to low traffic at home network 304).

[0104] At operation 314, UE 302 implicitly deregisters from its home network 304, for example, by handing over to roaming network 306. Typically, implicit deregistration can be based on a deregistration timer timeout, where there is no communication or contact between UE 302 and its home network 304 for the duration of the timer. In other words, if UE 302 does not periodically provide signs of life, UE 302 can be considered deregistered by its home network 304. Alternatively, implicit deregistration can be based on a trigger for re-registration to the roaming network (at UE 302), for example, because no suitable cell is available at the home network. Typically, deregistration at UE 302 (to home network 304) and deregistration at home network 304 (of UE 402) can occur at different times.

[0105] At operation 316, UE 302 registers with roaming network 306. For example, UE 302 may send, and roaming network 306 may receive, a registration request for registration with roaming network 306. In response, roaming network 306 may send, and UE 302 may receive, a registration response (e.g., a registration acceptance message). In some cases, after completing registration with roaming network 306, UE 302 may operate in idle mode and reside on roaming network 306.

[0106] At operation 318, UE 302 determines, for example, to return to home network 304 based on the fact that home network 304 has transitioned to an energy efficiency state and is operating in a normal state.

[0107] At operation 320, UE 302 implicitly deregisters from roaming network 306 by switching to camp on home network 304. Typically, implicit deregistration can be based on a deregistration timer timeout, where there is no communication or contact between UE 302 and roaming network 306 for the duration of the timer, or it can be based on a trigger for re-registration to the roaming network (at UE 302), for example, because no suitable cell is available on the home network. Typically, deregistration at UE 302 (to roaming network 306) and deregistration at roaming network 306 (for UE 402) can occur at different times.

[0108] At operation 322, when re-entering home network 304, UE 302 registers with home network 304 (re-registers).

[0109] At each registration (e.g., at operations 310, 316, 322), the corresponding home network 304 or roaming network 306 may create a UE context to store information related to UE 302, such as, but not limited to, information associated with UE capabilities and / or bearers(s) configured for the UE, information associated with services(s) configured for the UE, information associated with the UE's registration area (e.g., tracking area information), information associated with the UE's reachability configuration (e.g., paging capabilities and / or parameters, such as paging subgroup identifiers(s) and / or mobile initiation connections(s), information associated with one or more of the UE's capabilities, and information associated with the UE's security configuration (e.g., parameters associated with encryption and / or integrity protection). When UE 302 is located at the corresponding core network, the corresponding core network may store the UE context (e.g., at...). Figure 10 The UE context is located at memory 1050, but it can be released or deleted when UE 302 switches to another core network. That is, at operation 310, the home network 304 can create and store the UE context for UE 302, and the home network 304 can release or delete the UE context when UE 302 switches to roaming network 306 (leaving the home network 304). Similarly, at operation 316, the roaming network 306 can create and store the UE context for UE 302, and the roaming network 306 can release or delete the UE context when UE 302 switches to the home network 304 (leaving the roaming network 306).

[0110] As described above, if offloading UE 302 from home network 304 to roaming network 306 is for energy conservation, increasing C-plane load (e.g., from registration operations) may be counterproductive, increasing battery consumption at UE 302 and increasing power consumption and network resources at home network 304 and roaming network 306. Furthermore, if explicit deregistration is performed, for example, at operations 314 and / or 320, the C-plane load may increase further. Moreover, the aforementioned processes or operations 310-322 are per UE. Therefore, when a large number of UEs undergo such migrations, the re-registration operation to home network 304 (when UE 302 switches to home network 304) and / or the re-registration operation to roaming network 306 (when UE 302 switches to home network 304) will significantly increase the C-plane load.

[0111] Figure 3 The signals and operations described are illustrative only, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 3 Other signals and operations not illustrated herein. In embodiments, signals and operations may not include... Figure 3 Each signal and operation is shown. In an embodiment, the signals and operations can be in conjunction with... Figure 3 Different sequences are shown to be implemented. Such and other embodiments are considered to be within the scope of this disclosure.

[0112] In some scenarios, during low-traffic periods such as nighttime, the location of many UEs may not change (e.g., a UE may be stationary when a user is asleep). Therefore, during network sharing in these scenarios, a UE might leave its home network during the day (e.g., in registration area RA#1) and enter a roaming network (e.g., in registration area RA#2), leave the roaming network in RA#2, and return to its home network in RA#1 each night. If the UE's behavior is known to both the home and roaming core networks during roaming (e.g., for energy efficiency), the UE does not need to re-register when entering different networks (e.g., the home and roaming core networks).

[0113] In certain network sharing scenarios, it can be beneficial for the home core network to dynamically migrate its subscribers (e.g., UEs) from the home core network to (multiple) roaming core networks, rather than based on a static or fixed schedule.

[0114] The following describes example operations for reducing C-plane signaling for network operators with network sharing protocols, enabling a UE (e.g., UE 150) to dynamically migrate between networks (e.g., the home core network and one or more roaming core networks) without re-registering upon entering a pre-registered network. Figure 4A and Figure 4B Example signals and operations of the network system are shown. Figure 5 , Figure 6 and Figure 9 Example operation of the UE is shown. Figure 7 Example operation of a network device is shown (e.g., at the home core network). Figure 8 An example operation of a network device is shown (e.g., at a roaming core network).

[0115] Figure 4A and Figure 4B This diagram illustrates control plane signaling (e.g., messages) transmitted between UE 402, home network 404, and roaming network 406 according to one aspect of this disclosure, and the operations performed by UE 402, home network 404, and roaming network 406. Home network 404 may be operated by a first operator to which a subscriber of UE 402 has subscribed. Roaming network 406 may be operated by a second operator different from the first operator. In one aspect, UE 402 may correspond to... Figures 1A-1D UE 150, and each of the home network 404 and the roaming network 406 can have as referenced above. Figure 2 The entities mentioned above (e.g., access nodes of the access network and network functions of the core network). In one example, home network 404 and roaming network 406 can respectively correspond to the above references. Figure 1A The discussion focuses on Operator A's network and Operator B's network. In one example, Home Network 404 and Roaming Network 406 can respectively correspond to the references above. Figure 1C The discussion focuses on home networks and roaming networks. In one example, home network 404 and roaming network 406 can be respectively referred to in the above reference. Figure 1D The discussion focuses on home and roaming networks. Network entities are illustrative, and it is conceivable that other entities may participate in signaling or perform operations. In some examples, each of UE 402, home network 404, and roaming network 406 may include the use of, for example, […]. Figure 10 The illustrated components are used to implement these operations in the core network. In some examples, the operation of the home network 404 can be implemented by a core network entity (e.g., AMF 212) at the home network 404. Similarly, the operation of the roaming network 406 can be implemented by a core network entity (e.g., AMF 212) at the roaming network 406. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, as referenced above. Figures 2-3 Examples of discussion.

[0116] At operation 411, home network 404 and roaming network 406 establish a network sharing protocol (e.g., a roaming protocol for energy efficiency purposes as described above). The network sharing protocol may specify the maximum number of UE contexts that can be stored long-term at roaming network 406. Context storage has associated costs and can be a factor in determining scale (e.g., core network resources). Therefore, it may be beneficial for operators to agree on the number of these long-term UE contexts in the network sharing protocol. Alternatively or additionally, the network sharing protocol may include information (e.g., parameters) related to long-term UE contexts. In one example, long-term UE context information may include a list of long-term UE context identifiers that home network 404 may assign to UEs for long-term registration with roaming network 406. As will be discussed more fully below, roaming network 406 may accept a long-term registration request from a UE if the long-term registration request includes long-term UE context information that matches the information agreed upon in the network sharing protocol. In another example, long-term UE context identifiers may have a specific format scheme agreed upon between home network 404 and roaming network 406 to prevent spoofing. Alternatively or concurrently, the network sharing protocol may include information associated with the registration updater timer. For example, the network sharing protocol may specify the periodic duration or length during which the UE can update the roaming core network with UE mobility information.

[0117] At operation 412, UE 402 sends and home network 404 receives a registration request for registering with home network 404.

[0118] At operation 413, upon receiving a registration request, the home network 404 determines whether the UE 402 is eligible to register with the roaming network 406 for a long term (e.g., for energy efficiency purposes).

[0119] In some respects, the home network 404 can determine which of its UEs are suitable for long-term registration with the roaming core network based on various factors. For example, this determination may be based on at least one of the following: the mobility pattern of the relevant UE, the QoS associated with the relevant UE, the energy of the relevant UE, or the geographical location of the relevant UE.

[0120] In one example, home network 404 may determine UE 402's eligibility for long-term registration based on UE 402 exhibiting a low mobility pattern. For instance, the low mobility pattern may be based on UE 402's past history, which indicates that UE 402 registered with the same cell of home network 404 during the last certain number of transitions (e.g., 2, 3, 5, 6, 10, or more transitions) to and from roaming network 406. Alternatively, the low mobility pattern may be based on a prediction of UE 402's mobility pattern.

[0121] In one example, the home network 404 can determine whether UE 402 is eligible for long-term registration based on UE 402's QoS. For example, the home network 404 can determine to minimize UE 402's downtime (e.g., based on the UE being a high-priority UE). Alternatively, the allocation can be based on the UE's downtime requirements (e.g., high QoS subscription).

[0122] In one example, the home network 404 may determine that UE 402 is eligible for long-term registration based on the fact that UE 402 has unlimited energy resources (e.g., if UE 402 is plugged in to charge).

[0123] In one example, home network 404 can determine whether UE 402 is eligible for long-term registration based on the UE's geographical location within the registration area of ​​home network 404 (where network protocols may be applied).

[0124] In some respects, if the home network 404 determines that UE 402 is eligible for long-term registration, the home network 404 assigns a long-term UE context to UE 402. To this end, the home network 404 may configure and manage a pool of identifiers for the long-term UE context based on a network sharing protocol established at operation 411. For example, each long-term UE context identifier in the pool is specified (or agreed upon) in the network sharing protocol. The home network 404 may select an identifier for the long-term UE context from the long-term UE context identifier pool (provided based on the network sharing protocol established at operation 411). In other words, the home network 404 may assign a long-term UE context to UE 402 based on at least one of the following: UE 402's mobility mode, the QoS associated with UE 402, UE 402's power, UE 402's geographic location, or the network sharing protocol established at operation 411. Typically, the home network 404 may manage a pool of long-term UE contexts, where each long-term UE context may include an identifier for the corresponding long-term UE context (e.g., an identifier specified in the network sharing protocol) and any other UE context information.

[0125] A long-term UE context can be assigned to UE 402 for use in roaming network 406. That is, the long-term UE context is specific to roaming network 406 and UE 402. As will be discussed more fully below, the long-term UE context can be configured to be maintained by roaming network 406 and UE 402, and configured to allow UE 402 to switch from home network 404 to roaming network 406 without re-registering with roaming network 406.

[0126] At operation 414, the home network 404 sends and the UE 402 receives a registration response including information associated with the long-term UE context assigned to the UE 402. Upon receiving the information associated with the long-term UE context, the UE 402 may save (store) the long-term UE context information in the UE 402's memory (e.g., Figure 10 The memory is located at 1050.

[0127] Long-term UE context information may include at least a long-term UE context identifier for the assigned long-term UE context, wherein the long-term UE context identifier is one of the long-term UE context identifiers agreed upon in the network sharing protocol. Additionally, long-term UE context information may include registration update timer information. Alternatively, long-term UE context information may include information associated with a bearer configured for the UE. Alternatively, long-term UE context information may include information associated with a service configured for the UE. In one example, information associated with a bearer and / or service may include the context of a PDU session and the corresponding PDU session state (e.g., active or inactive). Alternatively, long-term UE context information may include information associated with the UE's registration area (e.g., tracking area information). Alternatively, long-term UE context information may include information associated with the UE's reachability configuration (e.g., paging capabilities and / or parameters, such as paging subgroup identifiers and / or mobile-initiated connections). Alternatively, long-term UE context information may include information associated with the UE's security configuration (e.g., parameters associated with encryption and / or integrity protection). Alternatively, long-term UE context information may include information associated with one or more of the UE's capabilities.

[0128] In some respects, the home network 404 may have network sharing protocols with multiple roaming networks and allow the UE 402 to roam to any of these roaming networks. Therefore, for each of the multiple roaming networks, the home network 404 may assign a long-term UE context to the UE 402. Thus, the registration response at operation 414 may include indications of multiple roaming networks and information associated with each long-term UE context assigned to the UE in connection with the respective roaming network. In some examples, after registering with the home network 404, the UE 402 may operate in idle mode and reside on the home network 404.

[0129] Subsequently, the home network 404 or a RAN node associated with the home network 404 (e.g., a node or component, such as a base station at a RAN similar to RAN 225) can transition from a first network state to a second network state (e.g., the UE will be offloaded to an offloaded state of another network). The network state transition can be the start of a network sharing period. The network state transition can be detected by the UE 402 or indicated to the UE 402 by the home network 404. Figure 4A As shown, at operation 415A, UE 402 can detect that home network 404 is transitioning to an offload state. In one example, when the offload state is an energy-efficiency state for power saving, the detection can be based on auxiliary information (previously provided to UE 402 by home network 404 or an associated RAN node) indicating a potential or planned sleep period. Therefore, UE 402 can detect the state transition based on the absence of a home network cell during that period. Alternatively, at operation 415B, home network 404 can send, and UE 402 can receive, an indication that home network 404 is transitioning to an offload state. In one example, home network 404 can send the network state transition indication via System Information Block (SIB) broadcast or any other suitable signaling.

[0130] At operation 416, the home network 404 sends and the roaming network 406 receives an indication that the home network 404 is offloading the UE to the roaming network 406. This indication can be used for network sharing activation. In some cases, the indication from the home network 404 to offload the UE to the roaming network 406 can be optional.

[0131] As described above, in some examples, UE offloading can be triggered by the home network 404 transitioning to an energy efficiency state. For this purpose, the coverage area of ​​the home network 404 can at least partially overlap with the coverage area of ​​the roaming network 406 (e.g., as referenced above). Figure 1D The home network 404 can transition its(multiple) cells to an energy-efficient state by shutting down(multiple) base stations and / or other network resources in the corresponding cell. Typically, after transitioning(multiple) cells to an energy-efficient state, the home network 404 can notify each roaming network with which it has a protocol of the change in state (to energy-efficient state). This indication can aid UE reachability (paging) during the energy-efficient state of the home network 404.

[0132] At operation 417, when an indication from home network 404 indicates that home network 404 is transitioning to an offload state, UE 402 implicitly deregisters from home network 404, for example, based on a deregistration timer timeout, wherein there is no communication or contact between UE 402 and home network 404 during the timer duration, or based on the triggering of a registration request to another network.

[0133] At operation 418, in response to a network state change detected at operation 415A or indicated by the home network 404 at operation 415B, UE 402 selects a roaming network for roaming. As described above, the registration response at operation 414 may include an indication of a roaming network list, and information associated with each long-term UE context assigned to the UE with the corresponding roaming network. Therefore, UE 402 can select a roaming network from the roaming network list indicated in the registration response. Figure 4A In the example shown, UE 402 selects roaming network 406.

[0134] After selecting roaming network 406, UE 402 can perform an initial registration with roaming network 406. For example, at operation 419, UE 402 sends and roaming network 406 receives a long-term registration request, which includes information associated with the long-term UE context assigned to UE 402 (used by home network 404 in roaming network 406). The information associated with the long-term UE context assigned to UE 402 can be referred to as long-term registration information.

[0135] At operation 420, the roaming network 406 verifies (or authenticates) the long-term registration information. As described above, the information associated with the long-term UE context may include a long-term UE context identifier. Furthermore, the network sharing protocol may include a set of long-term UE context identifiers agreed upon between the home network 404 and the roaming network 406. Therefore, as part of the verification or authentication, the roaming network 406 may determine whether the long-term UE context identifier received in the long-term registration request matches one of the long-term UE context identifiers agreed upon in the network sharing protocol. If the received long-term UE context identifier matches one of the agreed long-term UE context identifiers, the verification passes, and the roaming network 406 may accept the long-term registration request. However, if the received long-term UE context identifier does not match any of the agreed long-term UE context identifiers, the verification fails, and the roaming network 406 may reject the long-term registration request. Figure 4A In the example shown, the verification is successful, and the long-term registration request is accepted. After the roaming network 406 accepts the long-term registration request, the roaming network 406 can save (store) the long-term UE context (received from UE 402) in the roaming network 406's memory (e.g., Figure 10 (at memory 1050).

[0136] Therefore, at operation 421, roaming network 406 sends and UE 402 receives a long-term registration response (e.g., a registration acceptance message) including registration update timer information. The registration update timer information can be configured to be maintained by UE 402 and roaming network 406, and is configured to allow UE 402 to switch from home network 404 to roaming network 406 without re-registering with roaming network 406. Roaming network 406 can provide the registration update timer information to UE 402 based on the verification at operation 420. The registration update timer information can indicate information (e.g., a periodic time period) for configuring a periodic timer for UE 402 to perform registration updates to roaming network 406. In some aspects, the registration update timer information can include a periodic time period agreed upon in a network sharing protocol. In some aspects, roaming network 406 can allocate a reasonably long registration update time period (e.g., 30 minutes, 1 hour, or more than 2 hours).

[0137] In some examples, after registering with roaming network 406, UE 402 can operate in idle mode, residing on roaming network 406, and performing registration area updates based on registration update timer information. For example, at operation 422, UE 402 starts a registration update timer (e.g., a periodic timer) configured based on the registration update timer information received at operation 421. UE 402 can perform registration area updates, for example, according to a 3GPP registration area update procedure. For example, UE 402 can typically roam freely across cells within a registration area of ​​roaming network 406 (e.g., a registration area where UE 402 requests long-term registration) without having to perform location registration for each cell. When the registration update timer expires, UE 402 can perform a registration area update procedure to update the roaming network 406 and mobility information of its serving cell.

[0138] At operation 423, roaming network 406 may also initiate a registration update timer (e.g., a periodic timer) configured based on the same registration update timer information provided to UE 402 at operation 421. In other words, the registration update timer of roaming network 406 can be synchronized with the registration update timer at UE 402 for registration area update operations. Therefore, when the registration update timer of UE 402 expires, roaming network 406 can expect to receive a registration update from UE 402. The registration update (e.g., including UE 402's serving cell and mobility information) can serve as an indication that UE 402 is active and that UE 402's long-term registration (to roaming network 406) remains active or valid. If roaming network 406 does not receive a registration area update when the registration update timer expires, roaming network 406 can consider the long-term registration to UE 402 to be invalid and stop (or delete) the registration update timer. In some respects, roaming network 406 does not implicitly disconnect UE 402 as long as the registration update timer is running.

[0139] At operation 424, UE 402 switches back to reside on home network 404 (e.g., later). The handover from roaming network 406 to home network 404 can be based on a state change at home network 404 (e.g., when home network 404 transitions out of an offload state), where the state change can end a network sharing period.

[0140] At operation 429, the home network 404 sends and the roaming network 406 receives an indication of a state change at the home network 404. Although Figures 4A-4B The illustration shows the home network 404 sending a state change indication to the roaming network 406 after operation 424. In other cases, the home network 404 may send the state change indication to the roaming network 406 before operation 424. In some cases, the state change indication of the home network 404 may be optional.

[0141] As described above, when UE 402 receives a long-term UE context from home network 404 at operation 414, UE 402 can store the long-term UE context in its memory. At operation 425, UE 402 continues to maintain, save, retain, and / or store the long-term UE context associated with roaming network 406 while residing on home network 404. That is, when UE 402 switches from roaming network 406 to home network 404, UE 402 may not release or delete the long-term UE context associated with roaming network 406.

[0142] As described above, when roaming network 406 determines at operation 420 that the verification of the long-term UE context from UE 402 is successful, roaming network 406 may store the long-term UE context in its memory. At operation 426, when UE 402 is at home network 404, roaming network 406 continues to maintain, save, retain, and / or store the long-term UE context associated with UE 402. That is, when UE 402 switches from roaming network 406 to home network 404, roaming network 406 may not release or delete the long-term UE context of UE 402.

[0143] At operation 427, UE 402 determines that it wants to switch to residing on the pre-registered roaming network 406 (e.g., because home network 404 is transitioning to an offload state, as described above at operations 415A and / or 415B).

[0144] At operation 428, based on the long-term UE context, the running registration update timer, and the fact that UE 402's current registration region is the same as the registration region assigned to its long-term UE context, UE 402 resides on the pre-registered roaming network 406 without re-registering with roaming network 406. More specifically, UE 402 can re-enter roaming network 406 without re-registration if UE 402 meets the following two conditions: (1) the registration update timer configured at the UE according to the registration update timer information is running (e.g., in progress or active); and (2) UE 402 is in the same registration region as UE 402 when it requested the long-term registration request at operation 419 (i.e., UE 402's current registration region is the same as the registration region assigned and saved to its long-term UE context). Reference will be made below. Figure 5 The mechanism used to determine whether UE 402 needs to register when it enters the network is discussed in more detail. UE 402 can use the long-term UE context maintained at UE 402 to communicate with roaming network 406.

[0145] Similarly, if roaming network 406 determines that the registration update timer (start operation 423) associated with UE 402 is running, and UE 402 is located in the same registration area as the registration area where the long-term UE context is stored, then roaming network 406 can communicate with UE 402 using the long-term UE context maintained at roaming network 406.

[0146] As shown in the figure, since each of UE 402 and roaming network 406 continues to maintain and store long-term UE context after UE 402 leaves roaming network 406, UE 402 and roaming network 406 can communicate with each other using their own stored long-term UE context when UE 402 re-enters roaming network 406. Therefore, UE 402 does not need to re-register with roaming network 406 to re-establish the UE context for communication with roaming network 406.

[0147] In some cases, UE 402, which has been assigned a long-term UE context, may move out of the registration area to which its long-term UE context was assigned. In this case, UE 402 may follow the 3GPP registration update procedure and perform a registration area update procedure. During this procedure, due to the mobility of UE 402, roaming network 406 may revoke the long-term UE context of UE 402. For example, UE 402 may indicate that it has moved to a different registration area than the registration area that UE 402 last registered with roaming network 406. After the long-term UE context is revoked, when UE 402 leaves roaming network 406, roaming network 406 may delete the long-term UE context and notify UE 402 of the revocation of the long-term UE context (e.g., via a registration acceptance message). Typically, roaming network 406 can implicitly disconnect UE 402 from roaming network 406, or, after UE 402 leaves roaming network 406, explicitly notify UE 402 that UE 402 has disconnected from roaming network 406 via a long-term UE context revocation instruction. In other words, UE 402 can remain in roaming network 406, but when it leaves roaming network 406, the long-term UE context will not be stored for UE 402. When UE 402 returns to its home network 404, UE 402 can notify home network 404 that roaming network 406 has revoked the long-term UE context (assigned to UE 402 by home network 404), as will be referred to below. Figure 6 A more comprehensive discussion.

[0148] In some respects, the home network 404 can assign a subset of its UEs, each of which has a long-term UE context, such that when these UEs return from a network-shared period, they do not need to register with the home network 404 if their registered area has not changed.

[0149] As an example, home network 404 may allocate another long-term UE context (e.g., a second long-term UE context) to UE 402 for use within home network 404. Home network 404 may provide the second long-term UE context to UE 402 as part of the registration response at operation 414. The second long-term UE context may be configured to be maintained by both home network 404 and UE 402, and may be configured to allow UE 402 to switch from roaming network 406 to home network 404 without re-registering with home network 404.

[0150] In some examples, the home network 404 may provide registration update timer information to the UE 402 as part of the registration response at operation 414. Similar to the registration update timer information provided by the roaming network 406, the registration update timer information may include an indication of periodic timer periods for registration updates at the home network 404. Furthermore, for example at operation 419, after the UE 402 switches to register with the roaming network 406, each of the home network 404 and the UE 402 may continue to maintain a copy of the long-term UE context for use in the home network 404. Additionally, each of the home network 404 and the UE 402 may maintain a registration update timer associated with a second long-term UE context. The UE 402 may perform a registration area update with the home network 404, for example, according to the 3GPP registration area update procedure.

[0151] Subsequently, when UE 402 switches back to home network 404 (e.g., at operation 424), UE 402 does not need to re-register with home network 404 if the following two conditions are met: (1) the registration update timer configured at UE 402 in association with the second long-term UE context is running (e.g., in progress or active); and (2) UE 402 is in the same registration area as when UE 402 was last in home network 404 (i.e., the UE's current registration area is the same as the registration area assigned and saved by its second long-term UE context). In other words, when the above two conditions are met, UE 402 and home network 404 can communicate with each other without UE 402 re-registering with home network 404, each using its own maintained long-term UE context. In some examples, home network 404 may also provide an indication of whether UE 402's long-term UE context is valid in home network 404 (e.g., during the registration update process). In this way, if the long-term UE context is valid, UE 402 does not need to re-register with home network 404 when UE 402 returns to home network 404 next time (e.g., at the end of the next network sharing period).

[0152] In some respects, UE 402 may register different UE capabilities in different networks (e.g., different operator networks) for reasons related to multiple-input multiple-output (MIMO) configuration, carrier aggregation (CA) configuration, overheating issues, and / or operator configuration. Therefore, information associated with the long-term UE context provided to UE 402 by home network 404 at operation 414 may optionally include UE capabilities. Typically, UE capabilities may be included in the long-term UE context stored in roaming network 406, home network 404, and / or at the UE.

[0153] Figure 4A and Figure 4B The signals and operations described are illustrative only, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 4A and Figure 4B Other signals and operations not illustrated herein. In embodiments, signals and operations may not include... Figure 4A and Figure 4B Each signal and operation is shown. For example, in some cases, home network 404 can dynamically notify roaming network 406 whenever home network 404 transitions to a state requiring the UE to be offloaded to roaming network 406 (e.g., network sharing activated) and whenever home network 402 transitions out of that state (e.g., network sharing deactivated). Typically, home network 404 can notify roaming network 406 of its need for network sharing. In embodiments, signals and operations can be in accordance with... Figure 4A and Figure 4B Different sequences are shown for implementation. Such and other embodiments are considered to be within the scope of this disclosure.

[0154] Figure 5 This is a flowchart illustrating an example operation of a UE (User Equipment) roaming between networks according to one aspect of this disclosure. In one aspect, the UE may correspond to the above reference. Figures 1A-1D The UE discussed and / or the references above. Figure 4A and Figure 4B The UE 402 is discussed. In some examples, the UE can use features such as Figure 10 The apparatus shown in the diagram is used to perform these operations. Figure 5 The operations can include those mentioned above. Figure 4A and Figure 4B A similar mechanism is being discussed. As shown in the figure, Figure 5 It includes multiple enumeration steps, but Figure 5 The operations in the enumeration process can include additional steps before, after, and between the enumeration steps. In some aspects, one or more of the enumeration steps can be omitted or performed in a different order.

[0155] At box 502, the UE registers with its home core network (e.g., the core network of home network 404). For example, the UE may send a registration request to its home core network.

[0156] At box 504, the UE receives long-term registration information for each Public Land Mobile Network (PLMN) (e.g., for each of a plurality of PLMNs). In some aspects, the UE may receive long-term registration information for each PLMN in a registration response from the home core network. A PLMN may include a home core network (e.g., HPLMN) and one or more roaming core networks (e.g., VPLMN, the core network of roaming network 406). For example, the long-term registration information may include at least a long-term UE context identifier and registration update timer information for each PLMN. In some cases, for each PLMN, the long-term registration information may also include information associated with bearer configuration, service configuration, registration area configuration, UE reachability configuration, one or more UE capabilities, and / or UE security configuration.

[0157] At box 506, the UE determines that it wants to switch to a different network. For example, the UE determines that it wants to switch from its home core network to a roaming core network, such as, for example, similar to Figure 4A Operation 418.

[0158] At box 508, the UE determines whether it has previously registered with the network determined for the handover. If the UE has previously registered with the network, the UE may have already started a registration update timer associated with that network. Therefore, the UE can determine whether it has a running (active) registration update timer for the determined network as an indicator of whether the UE has previously registered with the determined network. If the UE determines that it has not previously registered with the determined network, the UE proceeds to box 510.

[0159] At box 510, the UE initiates registration with the determined network (e.g., initial registration). For example, the UE may send a long-term registration request, which includes long-term registration information (e.g., long-term UE context) assigned to the UE by the home core network in association with the determined network. If the long-term registration request is accepted by the determined network, the UE may receive a long-term registration acceptance response indicating that the long-term registration process has been successfully completed. The long-term registration acceptance response also includes registration update timer information (e.g., an indication of the duration (time length) of the periodic registration update timer).

[0160] At box 512, after the successful completion of the long-term registration process, the UE initiates (or starts) a periodic registration update timer. The UE can configure the periodic registration update timer based on the registration update timer information. The UE can update its mobility information to the roaming core network based on the registration update timer (e.g., when the registration update timer expires). The UE can also store a registration area identifier (ID) that identifies the UE's current registration area.

[0161] Returning to box 508, if the UE determines that it has previously registered with the determined network (i.e., the determined network is a pre-registered network), the UE proceeds to box 514. At box 514, the UE determines whether its current registration area is the same as the registration area when it previously registered with the determined network. For example, the UE can compare the registration area ID of the current registration area with the registration area ID of the previously registered area. For example, the UE can store the previously registered area ID after the previous registration. If the UE determines that its current registration area is different from the previously registered area (i.e., the current registration area ID is different from the previously registered area ID), the UE proceeds to box 510 and re-registers with the determined network. However, if the UE determines that its current registration area is the same as the previously registered area, the UE proceeds to box 516.

[0162] At box 516, the UE determines that it does not need to register with the determined network based on the fact that the periodic registration timer has not expired and the UE is in the same registration area. In other words, the UE can re-enter the determined network without re-registering with it.

[0163] Although Figure 5 This is discussed in the context of a UE switching from its home core network to a roaming core network, but the UE can also apply operations 508-516 to determine whether it needs to re-register with the home core network when it re-enters the home core network.

[0164] Figure 6 This is a flowchart illustrating an example operation of a UE migrating between networks according to one aspect of this disclosure. In one aspect, the UE may correspond to the above reference. Figures 1A-1D The UE discussed and / or the references above. Figure 4A and Figure 4B The UE 402 is discussed. In some examples, the UE can use features such as Figure 10 The apparatus shown in the diagram is used to perform these operations. Figure 6 The operations can include those mentioned above. Figure 4A and Figure 4B A similar mechanism is being discussed. As shown in the figure, Figure 6 It includes multiple enumeration steps, but Figure 6The operations in the enumeration process can include additional steps before, after, and between the enumeration steps. In some aspects, one or more of the enumeration steps can be omitted or performed in a different order.

[0165] At box 602, the UE registers with the roaming core network (e.g., the core network of roaming network 406). For example, the UE may send a long-term registration request for registration with the roaming core network. The long-term registration request may include a long-term UE context assigned to the UE by the UE's home core network (e.g., the core network of home network 404).

[0166] At box 604, the UE receives an instruction from the roaming core network to revoke long-term registration, for example, due to excessive mobility of the UE or a violation or abnormal breach of the network sharing protocol between the roaming core network and the home core network. In one example, excessive mobility may be based on a registration update provided by the UE to the roaming core network. For example, a registration update may indicate that the UE has moved to a different registration area than when the UE last registered with the roaming core network. In one example, the roaming core network may detect a violation or abnormal breach of the network protocol based on the fact that the number of active long-term UE contexts stored at the roaming core network has reached or exceeded a threshold number of long-term UE contexts agreed upon in the network sharing protocol.

[0167] At box 606, the UE determines that it wants to switch to its home core network.

[0168] At box 608, the UE initiates registration with its home core network. The UE may send a registration request to the home core network, including information about the roaming core network revoking its long-term registration with it. In other cases, the UE may re-enter the home core network without re-registering and may notify the home core network of the long-term registration revocation by the roaming core network during the registration update process. In one example, the UE may include information associated with the revoked long-term UE context in its registration update message to the home core network. For example, the registration update message may include a field indicating the status of the long-term UE context revocation and the long-term UE context identifier of the revoked long-term UE context.

[0169] Figure 7 This is a flowchart illustrating an example operation of a network device providing a long-term UE context to a UE according to one aspect of this disclosure. The network device is located in a first core network (e.g., the core network of a first operator) and can implement core network entities of the first core network (e.g., ...). Figure 2 The operation of AMF 212). In one respect, the first core network corresponds to the above reference. Figure 4A and Figure 4BThe core network of the home network 404 is discussed. In some examples, network devices can use those with features such as... Figure 10 The apparatus shown in the diagram is used to perform these operations. Figure 7 The operations can include those mentioned above. Figures 4A-4B and Figures 5-6 A similar mechanism is being discussed. As shown in the figure, Figure 7 It includes multiple enumeration steps, but Figure 7 The operations in the enumeration process can include additional steps before, after, and between the enumeration steps. In some aspects, one or more of the enumeration steps can be omitted or performed in a different order.

[0170] At frame 702, the network device (at the first core network) receives a registration request from the UE.

[0171] At box 704, the network device (at the first core network) assigns a long-term UE context to the UE. The long-term UE context is configured to be maintained by a second core network and is configured to allow the UE to switch from communicating with the first core network to communicating with the second core network without re-registering with the second core network. The second core network is the core network of a second operator, different from the first operator. In some respects, the first core network may be part of the UE's home network, and the second core network may be part of the UE's roaming network.

[0172] In some aspects, the long-term UE context information provided to the UE includes at least one of the following: an identifier associated with the long-term UE context (e.g., a long-term UE context identifier), registration update timer information, information associated with a bearer configured for the UE (e.g., associated with (multiple) Protocol Data Unit (PDU) sessions), information associated with a service configured for the UE (e.g., associated with (multiple) PDU sessions), information associated with the UE's registration area (e.g., tracking area information), information associated with the UE's reachability configuration (e.g., paging capabilities and / or parameters), information associated with one or more of the UE's capabilities, or information associated with the UE's security configuration (e.g., parameters associated with encryption and / or integrity protection).

[0173] At box 706, the network device (at the first core network) responds to the registration request by sending a registration response to the UE, the registration response including information about the long-term UE context assigned to the UE.

[0174] In some aspects, the network device also determines whether to assign a long-term UE context to a UE based on at least one of the following: the UE's mobility mode, the UE's QoS, the UE's power supply, the UE's geographic location, or the network sharing protocol between the first core network and the second core network, for example, as referenced above. Figure 4AAs described in operation 413.

[0175] In some aspects, the network device also selects an identifier for the long-term UE context from a long-term UE context identifier pool, which is provided based on a network sharing protocol between the first operator and the second operator, for example, as referenced above. Figure 4A As described in operation 413.

[0176] In some aspects, the network device will also offload at least the UE to the second core network. In other aspects, the network device will also transform the first core network into an energy-efficient state. For example, offloading the UE to the second core network can be based on transforming the first core network into an energy-efficient state.

[0177] In some aspects, the network device also receives an indication of revocation of a long-term UE context from the UE (e.g., sent to the UE by a second core network). In response to the indication of revocation of the long-term UE context, the network device deletes the long-term UE context assigned to the UE.

[0178] In some aspects, the network apparatus (at the first core network) also allocates a second long-term UE context to the UE. The second long-term UE context is configured to be maintained by the first core network entity and is configured to allow the UE to switch from communicating with the second core network to communicating with the first core network without re-registering with the first core network. In some aspects, the network apparatus (at the first core network) also maintains a registration update timer associated with the second long-term UE context. For example, when the registration update timer expires, the first core network may expect to receive a registration update from the UE. The registration update (e.g., including the UE's serving cell and mobility information) can serve as an indication that the UE is active and that the second long-term UE context remains valid for use in the first core network.

[0179] Figure 8 This is a flowchart illustrating an example operation of a network device performing long-term registration with a UE according to one aspect of this disclosure. The network device is located in a first core network (e.g., the core network of a first operator) and can implement core network entities of the first core network (e.g., Figure 2 The operation of AMF 212). In one respect, the first core network corresponds to the above reference. Figure 4A and Figure 4B The roaming network discussed is 406. The network device can implement the core network entity of the first core network (e.g., Figure 2 The operation of AMF 212). In some examples, the network device can use features such as Figure 10 The apparatus shown in the diagram is used to perform these operations. Figure 8 The operations can include those mentioned above. Figures 4A-4B and Figures 5-6A similar mechanism is being discussed. As shown in the figure, Figure 8 It includes multiple enumeration steps, but Figure 8 The operations in the enumeration process can include additional steps before, after, and between the enumeration steps. In some aspects, one or more of the enumeration steps can be omitted or performed in a different order.

[0180] At box 802, the network device (at the first core network) receives a long-term registration request from the UE, which includes information about the UE's long-term UE context.

[0181] At box 804, the network device of the first core network (located in the first core network) sends registration update timer information to the UE in response to a long-term registration request. The registration update timer information is configured to be maintained by the UE and is configured to allow the UE to switch from communicating with the second core network to communicating with the first core network without re-registering with the first core network. The second core network is the core network of a second operator, which is different from the first operator. In one example, the UE's long-term UE context is assigned by the second core network. In some respects, the first core network is part of the UE's roaming network, and the second core network is part of the UE's home network.

[0182] In some respects, at least one of the UE's long-term UE context or registration update timer information is provided based on a network sharing protocol between the first operator and the second operator.

[0183] In some aspects, the long-term UE context information in the long-term registration request received at box 802 includes at least one of the following: an identifier associated with the long-term UE context (e.g., a long-term UE context identifier), registration update timer information, information associated with a bearer configured for the UE (e.g., associated with multiple Protocol Data Unit (PDU) sessions), information associated with a service configured for the UE (e.g., associated with multiple PDU sessions), information associated with the UE's registration area (e.g., tracking area information), information associated with the UE's reachability configuration (e.g., paging capabilities and / or parameters), information associated with one or more of the UE's capabilities, or information associated with the UE's security configuration (e.g., parameters associated with encryption and / or integrity protection).

[0184] In some respects, network devices also authenticate identifiers of long-term UE contexts, for example, as referenced above. Figure 4A As described in operation 420.

[0185] In some aspects, the network device also maintains the UE's long-term UE context in memory (e.g., Figure 10The maintained UE long-term context is used at memory 1050, and when the UE switches from communicating with the second core network to communicating with the first core network, for example, as referenced above. Figure 4B As described in operation 428.

[0186] In some aspects, the network device also revokes the UE's long-term UE context based on at least one of the UE's mobility mode (e.g., excessive mobility) or a network sharing agreement between the operator and a second operator. In some aspects, the network device also sends an indication to the UE that the UE's long-term UE context has been revoked.

[0187] Figure 9 This is a flowchart illustrating an example operation of a UE migrating between networks according to one aspect of this disclosure. In one aspect, the UE corresponds to the reference above. Figures 1A-1D UE 150 or the above references are discussed. Figure 4A and Figure 4B The UE402 is discussed. In some examples, the UE can use features such as Figure 10 The apparatus shown in the diagram is used to perform these operations. Figure 9 The operations can include those mentioned above. Figures 4A-4B and Figures 5-6 A similar mechanism is being discussed. As shown in the figure, Figure 9 It includes multiple enumeration steps, but Figure 9 The operations in the enumeration process can include additional steps before, after, and between the enumeration steps. In some aspects, one or more of the enumeration steps can be omitted or performed in a different order.

[0188] At box 902, the UE receives information about a long-term UE context assigned to the UE in association with a first core network. The long-term UE context is configured to enable the UE to switch from communicating with a second core network to communicating with the first core network without re-registering with the first core network. In some respects, one of the first core network or the second core network is part of the UE's home network, and the other of the first core network and the second core network is part of the UE's roaming network.

[0189] In some aspects, long-term UE context information includes at least one of the following: an identifier associated with the long-term UE context (e.g., a long-term UE context identifier), registration update timer information, information associated with a bearer configured for the UE (e.g., associated with multiple Protocol Data Unit (PDU) sessions), information associated with a service configured for the UE (e.g., associated with multiple PDU sessions), information associated with the UE's registration area (e.g., tracking area information), information associated with the UE's reachability configuration (e.g., paging capabilities and / or parameters), information associated with one or more of the UE's capabilities, or information associated with the UE's security configuration (e.g., parameters associated with encryption and / or integrity protection).

[0190] At box 904, the UE switches from communication with the second core network to communication with the first core network, wherein communication with the first core network is based on a long-term UE context. In some aspects, the handover responds to an energy efficiency state transition associated with the second core network. In some aspects, communication with the first core network may include receiving paging information from the first core network (e.g., when the UE is camped on the first core network). In some aspects, communication with the first core network may include sending and / or receiving registration messages associated with a registration update procedure.

[0191] In some respects, long-term UE context is assigned to the UE based on at least one of the following: the UE's mobility mode, the UE's QoS, the UE's energy, the UE's geographic location, or a network sharing protocol between the first operator and the second operator, for example, as referenced above. Figure 4A As described in operation 413.

[0192] In some respects, when the UE communicates with the second core network, the UE also maintains a long-term UE context associated with the first core network (e.g., in...). Figure 10 The memory (at location 1050) is used for communication with the first core network, where communication is based on a maintained long-term UE context. For example, when the UE switches to communicating with the first core network, the UE can retrieve the maintained long-term UE context from the memory and use the maintained long-term UE context for communication with the first core network.

[0193] In some aspects, the long-term UE context at box 902 can be assigned to the UE by the second core network for use in the first core network. For example, the second core network could be the UE's home core network, and the first core network could be the UE's roaming core network. Therefore, in some cases, the UE also sends a registration request to the second core network for registration with the second core network, and as part of receiving the long-term UE context information at box 902, in response to the registration request, the UE receives a registration response from the second core network including the long-term UE context information. In some cases, the UE also sends a long-term registration request to the first core network including the long-term UE context information. In response to the long-term registration request, the UE receives information associated with a registration update timer from the first core network. In some cases, based on the long-term UE context and based on the ongoing registration update timer associated with the first core network, the UE communicates with the first core network without re-registering with the first core network.

[0194] In other aspects, the long-term UE context at box 902 can be assigned to the UE by the first core network for use within that core network. For example, the first core network could be the UE's home core network, and the second core network could be the UE's roaming core network. Therefore, in some cases, the UE also sends a registration request to the first core network for registration with the first core network, and as part of the information of the long-term UE context received at box 902, the UE also receives a registration response from the first core network, including information about the long-term UE context, in response to the registration request. In some cases, the UE also receives an indication from the first core network that the long-term UE context associated with the first core network has been revoked. In response to the indication that the long-term UE context associated with the first core network has been revoked, the UE releases the long-term UE context. In some cases, the UE also sends a notification to the second core network to inform it that the long-term UE context associated with the first core network has been revoked.

[0195] Now for reference Figure 10 This diagram illustrates a block diagram of example components of a UE or network device. The device includes an electronic storage device 1010, a processor 1020, a memory 1050, and a network interface 1040. The various components can be communicatively coupled to each other. The processor 1020 can be and may include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a system-on-a-chip (SoC), or any other type of processor. The memory 1050 can be a volatile type of memory, such as RAM, or a non-volatile type of memory, such as NAND flash memory. The memory 1050 includes processor-readable instructions executable by the processor 1020 to cause the device to perform various operations, including those described herein, such as... Figure 3, Figures 4A-4B and Figure 9 The operation.

[0196] Electronic storage device 1010 can be and includes any type of electronic storage device for storing data, such as hard disk drives, solid-state drives and / or optical disks, and other types of electronic storage devices. Electronic storage device 1010 stores processor-readable instructions for causing the device to perform its operations, and stores data associated with such operations, such as data related to the 5G NR standard and other data. Network interface 1040 can implement wireless network technologies, such as 5G NR and / or other wireless network technologies.

[0197] Figure 10 The components shown are merely examples, and those skilled in the art will understand that the apparatus includes other components not shown, and may include any multiple of the components shown. Such and other embodiments are considered to be within the scope of this disclosure.

[0198] Other embodiments of this disclosure include the following examples.

[0199] Example 1.1. A method comprising: The first core network entity of the first core network receives the registration request from the user equipment (UE), wherein the first core network is the core network of the first operator; The first core network entity allocates a long-term UE context to the UE, the long-term UE context being configured to be maintained by a second core network and configured to allow the UE to switch from communicating with the first core network to communicating with the second core network without re-registering with the second core network, wherein the second core network is the core network of a second operator, which is different from the first operator; and In response to the registration request, a registration response including the long-term UE context assigned to the UE is sent to the UE.

[0200] Example 1.2. The method described in Example 1.1 further includes: Determine whether to provide the long-term UE context to the UE based on at least one of the following: The UE's mobility mode, The UE's Quality of Service (QoS) The energy of the UE, The geographical location of the UE, or The maximum number of long-term UE contexts for a UE based on the network sharing protocol between the first operator and the second operator.

[0201] Example 1.3. The method according to Example 1.1 or Example 1.2 further includes: The first core network entity selects an identifier for the long-term UE context from a long-term UE context identifier pool, wherein the long-term UE context identifier pool is provided based on a network sharing protocol between the first operator and the second operator.

[0202] Example 1.4. The method according to any one of Examples 1.1 to 1.3, wherein the long-term UE context assigned to the UE includes at least one of the following: The identifier of the long-term UE context, Register and update timer information. Information associated with the bearer configured for the UE, Information associated with the services configured for the UE. Information associated with the UE's registration area, Information associated with the reachability configuration of the UE, or Information associated with the security configuration of the UE, or Information associated with one or more capabilities of the UE.

[0203] Example 1.5. The method according to any one of Examples 1.1 to 1.4, wherein: The first core network is part of the UE's home network, and The second core network is part of the UE's roaming network.

[0204] Example 1.6. The method according to any one of Examples 1.1 to 1.5 further includes: offloading the communication of the UE to the second core network by the first core network entity.

[0205] Example 1.7. The method according to Example 1.6 further includes: transitioning from the first core network entity to an energy efficiency state.

[0206] Example 1.8. The method according to any one of Examples 1.1 to 1.7 further includes: The first core network entity receives from the UE an instruction from the second core network to revoke the long-term UE context; and The first core network entity deletes the long-term UE context of the UE in response to the instruction to revoke the long-term UE context received.

[0207] Example 1.9. The method according to any one of Examples 1.1 to 1.5 further includes: The first core network entity allocates a second long-term UE context to the UE. The second long-term UE context is configured to be maintained by the first core network entity and is configured to allow the UE to switch communication from the second core network to the first core network without re-registering with the first core network.

[0208] Example 1.10. The method according to Example 1.9 further includes: Maintain the registration update timer associated with the second long-term UE context.

[0209] Example 2.1. A method comprising: A long-term registration request is received from a user equipment (UE) by a first core network entity of the first core network, the long-term registration request including the long-term UE context of the UE, wherein the first core network is the core network of the first operator; and In response to the long-term registration request, the first core network entity sends registration update timer information to the UE. The registration update timer information is configured to be maintained by the UE and is configured to allow the UE to switch from communicating with the second core network to communicating with the first core network without re-registering with the first core network. The second core network is the core network of a second operator, which is different from the first operator.

[0210] Example 2.2. The method according to Example 2.1, wherein the first core network is part of the UE's roaming network, and wherein the second core network is part of the UE's home network.

[0211] Example 2.3. The method according to Example 2.1 or Example 2.2, wherein at least one of the long-term UE context or the registration update timer information of the UE is provided based on a network sharing protocol between the first operator and the second operator.

[0212] Example 2.4. The method according to any one of Examples 2.1 to 2.3, wherein the long-term UE context includes at least one of the following: The identifier of the long-term UE context, Information associated with the bearer configured for the UE, Information associated with the services configured for the UE. Information associated with the UE's registration area, Information associated with the reachability configuration of the UE, Information associated with the security configuration of the UE, or Information associated with one or more capabilities of the UE.

[0213] Example 2.5. The method described in Example 2.4 further includes: The identifier that authenticates the long-term UE context.

[0214] Example 2.6. The method according to any one of Examples 2.1 to 2.5 further includes: Maintain the long-term UE context of the UE at the first core network; and When the UE switches from the second core network to the first core network, the maintained long-term UE context is used for the UE.

[0215] Example 2.7. The method according to Examples 2.1 to 2.6 further includes: The first core network entity may revoke the long-term UE context of the UE based on at least one of the UE's mobility mode or the network sharing protocol between the first operator and the second operator.

[0216] Example 2.8. The method described in Example 2.7 further includes: The first core network entity sends an indication to the UE that the long-term UE context of the UE has been revoked.

[0217] Example 3.1. A method comprising: A user equipment (UE) receives a long-term UE context associated with a first core network, the long-term UE context being configured to enable the UE to switch from communicating with a second core network of a second operator to communicating with the first core network without re-registering with the first core network, wherein the first core network is the core network of the first operator, and wherein the second core network is the core network of a second operator different from the first operator; and The UE switches communication with the second core network to communication with the first core network, wherein the communication with the first core network is based on the long-term UE context.

[0218] Example 3.2. According to the method described in Example 3.1, one of the first core network or the second core network is part of the UE's home network, and the other of the first core network or the second core network is part of the UE's roaming network.

[0219] Example 3.3. The method according to any one of Examples 3.1 to 3.2 further includes: When the UE communicates with the second core network, the UE maintains the long-term UE context associated with the first core network.

[0220] Example 3.4. The method according to any one of Examples 3.1 to 3.3, wherein the long-term UE context includes at least one of the following: The identifier of the long-term UE context, Register and update timer information. Information associated with the bearer configured for the UE, Information associated with the services configured for the UE. Information associated with the UE's registration area, Information associated with the reachability configuration of the UE, Information associated with the security configuration of the UE, or Information associated with one or more capabilities of the UE.

[0221] Example 3.5. The method according to any one of Examples 3.1 to 3.4 further includes: The UE sends a registration request to the second core network to register with the second core network. The receipt of the long-term UE context includes: In response to the registration request, a registration response including the long-term UE context is received from the second core network.

[0222] Example 3.6. The method according to any one of Examples 3.1 to 3.5 further includes: The UE sends a long-term registration request, including the long-term UE context, to the first core network, and In response to the long-term registration request, the UE receives information associated with the registration update timer from the first core network.

[0223] Example 3.7. The method according to any one of Examples 3.6 further includes: The UE resides on the first core network without re-registering with the first core network, based on the long-term UE context and the ongoing registration update timer associated with the first core network.

[0224] Example 3.8. The method according to any one of Examples 3.1 to 3.4 further includes... The UE sends a registration request to the first core network to register with the first core network. The receipt of the long-term UE context includes: In response to the registration request, the UE receives a registration response, including the long-term UE context, from the first core network.

[0225] Example 3.9. The method according to any one of Examples 3.1 to 3.8 further includes: The UE receives an indication from the first core network that the long-term UE context associated with the first core network has been revoked; and In response to the indication that the long-term UE context associated with the first core network has been revoked, the long-term UE context is released by the UE.

[0226] Example 3.10. The method according to Example 3.9 further includes: The UE sends a notification to the second core network to inform the second core network that the long-term UE context associated with the first core network has been revoked.

[0227] Example 3.11. The method according to any one of Examples 3.1 to 3.10, wherein the switching to communication with the first core network is in response to an energy efficiency state transition associated with the second core network.

[0228] Example 4. An apparatus comprising: At least one processor; and At least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform at least the method according to any one of Examples 1.1 to 1.10.

[0229] Example 5. An apparatus comprising: At least one processor; and At least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform at least one of Examples 2.1 to 2.8.

[0230] Example 6. An apparatus comprising: At least one processor; and At least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform at least the method according to any one of Examples 3.1 to 3.11.

[0231] Example 7. A non-transitory processor-readable medium comprising program code that, when executed by one or more processors, causes the one or more processors to perform at least the method according to any one of Examples 1.1 to 1.10.

[0232] Example 8. A non-transitory processor-readable medium comprising program code that, when executed by one or more processors, causes the one or more processors to perform at least one of Examples 2.1 to 2.8.

[0233] Example 9. A non-transitory processor-readable medium comprising program code that, when executed by one or more processors, causes the one or more processors to perform at least the method according to any one of Examples 3.1 to 3.11.

[0234] The embodiments and aspects disclosed herein are examples of this disclosure and may be embodied in various forms. For example, although some embodiments herein are described as separate embodiments, each embodiment herein may be combined with one or more other embodiments herein. The specific structural and functional details disclosed herein should not be construed as limiting, but rather serve as the basis for the claims and as a representative basis for teaching those skilled in the art to use this disclosure in various ways in virtually any suitably detailed structure. Throughout the description of the drawings, the same reference numerals may refer to similar or identical elements.

[0235] According to this disclosure, the phrases “in one aspect,” “in some aspects,” “in all aspects,” “in some aspects,” or “in other aspects” can each refer to one or more of the same or different aspects. The phrase “multiple” can refer to two or more.

[0236] According to this disclosure, the phrases “in one embodiment,” “in an embodiment,” “in various embodiments,” “in some embodiments,” or “in other embodiments” can each refer to one or more of the same or different embodiments. A phrase of the form “A or B” means “(A), (B), or (A and B).” A phrase of the form “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).”

[0237] Any method, program, algorithm, or code described herein can be translated into or represented in a programming language or computer program. The terms "programming language" and "computer program" as used herein each include any language used to specify computer instructions, and include (but are not limited to) the following languages ​​and their derivatives: assembly language, Basic, batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, meta-languages ​​that specify the program itself, and all first-, second-, third-, fourth-, fifth-, or later computer languages. Databases and other data schemas, and any other meta-languages, are also included. No distinction is made between interpreted, compiled, or both compiled and interpreted languages. No distinction is made between compiled and source code versions of a program. Therefore, if a programming language can exist in more than one state (such as source, compilation, object, or link), a reference to a program is a reference to any and all such states. A reference to a program can encompass the actual instructions and / or the intent of those instructions.

[0238] While various aspects of this disclosure are shown in the accompanying drawings, they are not intended to limit the disclosure thereto, as the scope of this disclosure should be as broad as possible, and the specification should be read in the same manner. Therefore, the above description should not be construed as limiting, but merely as examples of specific aspects. Those skilled in the art will be able to conceive of other modifications within the scope and spirit of the appended claims.

Claims

1. A method for defining a first core network entity of a first core network, the method comprising: Receive a registration request from a user equipment (UE), wherein the first core network is the core network of the first operator; A long-term UE context is assigned to the UE, the long-term UE context being configured to be maintained by a second core network and configured to allow the UE to switch from communicating with the first core network to communicating with the second core network without re-registering with the second core network, wherein the second core network is the core network of a second operator, which is different from the first operator; as well as In response to the registration request, a registration response is sent to the UE, the registration response including the long-term UE context assigned to the UE.

2. The method according to claim 1, further comprising: Determine whether to provide the long-term UE context to the UE based on at least one of the following: The UE's mobility mode, The UE's Quality of Service (QoS) The energy of the UE, The geographical location of the UE, or The maximum number of long-term UE contexts for a UE based on the network sharing protocol between the first operator and the second operator.

3. The method according to claim 1 or 2, further comprising: An identifier is selected for the long-term UE context from a long-term UE context identifier pool, wherein the long-term UE context identifier pool is provided based on a network sharing protocol between the first operator and the second operator.

4. The method according to any one of claims 1 to 3, wherein the long-term UE context assigned to the UE comprises at least one of the following: The identifier of the long-term UE context, Register and update timer information. Information associated with the bearer configured for the UE, Information associated with the services configured for the UE. Information associated with the UE's registration area, Information associated with the reachability configuration of the UE, or Information associated with the security configuration of the UE, or Information associated with one or more capabilities of the UE.

5. The method according to any one of claims 1 to 4, wherein: The first core network entity is part of the UE's home network, and The second core network is part of the UE's roaming network.

6. The method according to any one of claims 1 to 5, further comprising: The UE's communication is offloaded to the second core network.

7. The method according to claim 6, further comprising: Switch to energy efficiency mode.

8. The method according to any one of claims 1 to 7, further comprising: The UE receives an instruction from the second core network to revoke the long-term UE context; as well as In response to receiving the indication of revocation of the long-term UE context, the long-term UE context of the UE is deleted.

9. The method according to any one of claims 1 to 5, further comprising: A second long-term UE context is assigned to the UE, the second long-term UE context being configured to be maintained by the first core network entity and configured to allow the UE to switch communication from the second core network to the first core network without re-registering with the first core network.

10. The method of claim 9, further comprising: Maintain the registration update timer associated with the second long-term UE context.

11. A method for defining a first core network entity of a first core network, the method comprising: Receive a long-term registration request from a user equipment (UE), the long-term registration request including the long-term UE context of the UE, wherein the first core network is the core network of the first operator; as well as In response to the long-term registration request, a registration update timer is sent to the UE. The registration update timer is configured to be maintained by the UE and to allow the UE to switch from communicating with a second core network to communicating with the first core network without re-registering with the first core network. The second core network is the core network of a second operator, which is different from the first operator.

12. The method of claim 11, wherein the first core network is part of the UE's roaming network, and wherein the second core network is part of the UE's home network.

13. The method according to claim 11 or 12, wherein at least one of the long-term UE context of the UE or the registration update timer information is provided based on a network sharing protocol between the first operator and the second operator.

14. The method according to any one of claims 11 to 13, wherein the long-term UE context comprises at least one of the following: The identifier of the long-term UE context, Information associated with the bearer configured for the UE, Information associated with the services configured for the UE. Information associated with the UE's registration area, Information associated with the reachability configuration of the UE, Information associated with the security configuration of the UE, or Information associated with one or more capabilities of the UE.

15. The method of claim 14, further comprising: The identifier that authenticates the long-term UE context.

16. The method according to any one of claims 11 to 15, further comprising: Maintain the long-term UE context of the UE; as well as When the UE switches from the second core network to the first core network, the maintained long-term UE context is used for the UE.

17. The method according to claims 11 to 16, further comprising: The long-term UE context of the UE is revoked based on at least one of the UE's mobility mode or the network sharing protocol between the first operator and the second operator.

18. The method of claim 17, further comprising: Send an indication to the UE that the long-term UE context of the UE has been revoked.

19. A method for a user equipment (UE), the method comprising: Receive a long-term UE context associated with a first core network and assigned to the UE, the long-term UE context being configured to enable the UE to switch from communicating with a second core network of a second operator to communicating with the first core network without re-registering with the first core network, wherein the first core network is the core network of the first operator, and wherein the second core network is the core network of the second operator, which is different from the first operator; as well as The communication with the second core network is switched to the communication with the first core network, wherein the communication with the first core network is based on the long-term UE context.

20. The method of claim 19, wherein one of the first core network or the second core network is part of the UE's home network, and wherein the other of the first core network or the second core network is part of the UE's roaming network.

21. The method according to any one of claims 19 to 20, further comprising: When the UE communicates with the second core network, the UE maintains the long-term UE context associated with the first core network.

22. The method according to any one of claims 19 to 21, wherein the long-term UE context comprises at least one of the following: The identifier of the long-term UE context, Register and update timer information. Information associated with the bearer configured for the UE, Information associated with the services configured for the UE. Information associated with the UE's registration area, Information associated with the reachability configuration of the UE, Information associated with the security configuration of the UE, or Information associated with one or more capabilities of the UE.

23. The method according to any one of claims 19 to 22, further comprising: Send a registration request to the second core network to register with the second core network. The receipt of the long-term UE context includes: In response to the registration request, a registration response including the long-term UE context is received from the second core network.

24. The method according to any one of claims 19 to 23, further comprising: Send a long-term registration request, including the long-term UE context, to the first core network, and In response to the long-term registration request, the UE receives information associated with the registration update timer from the first core network.

25. The method of claim 24, further comprising: Based on the long-term UE context and the ongoing registration update timer associated with the first core network, the UE resides on the first core network without re-registering with the first core network.

26. The method according to any one of claims 19 to 22, further comprising: Send a registration request to the first core network to register with the first core network. The receipt of the long-term UE context includes: In response to the registration request, a registration response including the long-term UE context is received from the first core network.

27. The method according to any one of claims 19 to 26, further comprising: Receive an indication from the first core network that the long-term UE context associated with the first core network has been revoked; as well as In response to the indication that the long-term UE context associated with the first core network has been revoked, the long-term UE context is released.

28. The method of claim 27, further comprising: A notification is sent to the second core network to inform it that the long-term UE context associated with the first core network has been revoked.

29. The method of any one of claims 19 to 28, wherein the switching to the communication with the first core network is in response to an energy efficiency state transition associated with the second core network.

30. An apparatus comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform at least the method according to any one of claims 1 to 18.

31. A user equipment, comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to perform at least the method according to any one of claims 19 to 29.

32. A computer program comprising instructions, wherein execution of the computer program by at least one processor of the apparatus causes the apparatus to perform the method according to any one of claims 1 to 18.

33. A computer program comprising instructions, wherein execution of the computer program by at least one processor of a user equipment causes the user equipment to perform the method according to any one of claims 19 to 29.

34. A computer-readable medium comprising instructions that, when executed by at least one processor of a device, cause the device to perform the method according to any one of claims 1 to 10.

35. A computer-readable medium comprising instructions that, when executed by at least one processor of a user equipment, cause the user equipment to perform the method according to any one of claims 19 to 29.

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