Enhancements for handover

Abstract

Example embodiments of the present disclosure relate to enhancements to terminal device handover. In one aspect, during a handover from a first cell of a first access network to a second cell of a second access network, a second core network receives a first closed group identification (ID) of the first cell from a first core network; and determines a second closed group ID associated with one of a CSG ID or a CAG ID based on the first closed group ID. In this way, the second closed group ID will be used by the target cell, and access control from the first cell to the second cell can be implemented by the second core network based on the second closed group ID and related subscription information.

Description

Technical Field

[0001] Various example embodiments relate to the field of communications, and particularly to enhanced devices, methods, apparatuses, and computer-readable storage media for handover of terminal devices. Background Technology

[0002] With the development of communication technology, version 19 proposed a research project on femtocell support in fifth-generation (5G) communication networks. In Long Term Evolution (LTE) femtocell networks, Closed Subscriber Groups (CSGs) designate a set of authorized users who are allowed access to specific CSG cells within a Public Land Mobile Network (PLMN) via a designated CSG identifier (ID). In 5G, Closed Access Groups (CAGs) serve a similar purpose, authorizing specific subscribers to access designated CAG cells associated with a CAG ID. However, some issues still exist with cells in communication networks, particularly femtocells in 4G, 5G, etc., which require further research and resolution. Summary of the Invention

[0003] In general, the exemplary embodiments of this disclosure provide a technical solution for improving or enhancing the switching of terminal devices between two cellular types.

[0004] In a first aspect, a second core network is provided. The second core network may include: at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the second core network to perform at least: during a handover of a device from a first cell of a first access network to a second cell of a second access network, receiving from the first core network associated with the first access network a first closed group identifier (ID) of the first cell, wherein the first cell belongs to one of a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), the second cell belongs to the other of the CSG or CAG, and the first closed group ID is associated with one of the CSG or CAG; and determining a second closed group ID associated with the other of the CSG ID or CAG ID based on the first closed group ID.

[0005] In a second aspect, a first access network is provided. The first access network may include: at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the first access network to perform at least: during a handover of a device from a first cell of the first access network to a second cell of the second access network, determining a closed group ID of the second cell based on the cell identifier (ID) of the second cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; and transmitting the closed group ID of the second cell to a first core network.

[0006] In a third aspect, an apparatus is provided. The apparatus may include: at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: during a handover from a first cell of a first access network to a second cell of a second access network, acquire a closed group identifier (ID) of the second cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; and send a measurement report including the closed group ID of the second cell to the first access network.

[0007] In a fourth aspect, a second core network is provided. The second core network may include: at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the second core network to perform at least the following: during a handover of a device from a first cell of a first access network to a second cell of a second access network, receiving from the first core network associated with the first access network a closed group identifier (ID) of the first cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; based on the received closed group ID of the first cell, obtaining from network functions a list of allowed closed group IDs associated with the other of the CSG or CAG of the device; and sending the list of allowed closed group IDs to the second access network.

[0008] In a fifth aspect, a method implemented at a second core network is provided. The method may include: during a handover of a device from a first cell of a first access network to a second cell of a second access network, receiving from a first core network associated with the first access network a first closed group identifier (ID) of the first cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), the second cell belongs to the other CSG or CAG, and the first closed group ID is associated with either the CSG or CAG; and determining a second closed group ID associated with the other CSG ID or CAG ID based on the first closed group ID.

[0009] In a sixth aspect, a method implemented at a first access network is provided. The method may include: during a handover of a device from a first cell in the first access network to a second cell in a second access network, determining a closed group ID of the second cell based on the cell identifier (ID) of the second cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; and sending the closed group ID of the second cell to a first core network.

[0010] In a seventh aspect, a method implemented at a device is provided. The method may include: during a handover of the device from a first cell of a first access network to a second cell of a second access network, acquiring a closed group identifier (ID) of the second cell, wherein the first cell belongs to either a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of the CSG or CAG; and sending a measurement report including the closed group ID of the second cell to the first access network.

[0011] In an eighth aspect, a method implemented at a second core network is provided. The method may include: during a handover of a device from a first cell of a first access network to a second cell of a second access network, receiving from a first core network associated with the first access network a closed group identifier (ID) of the first cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; based on the received closed group ID of the first cell, obtaining from network functions a list of allowed closed group IDs associated with the other of the CSG or CAG for the device; and sending the list of allowed closed group IDs to the second access network.

[0012] In a ninth aspect, an apparatus is provided. The apparatus may include: components for receiving, during a handover of the device from a first core network associated with the first access network, a first closed group identifier (ID) of the first cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), the second cell belongs to the other of the CSG or CAG, and the first closed group ID is associated with either the CSG or CAG; and components for determining, based on the first closed group ID, a second closed group ID associated with the other of the CSG ID or CAG ID.

[0013] In a tenth aspect, an apparatus is provided. The apparatus may include: components for determining a closed group ID of a second cell based on a cell identifier (ID) of the second cell during a handover of the device from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to either a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of the CSG or CAG; and components for transmitting the closed group ID of the second cell to a first core network.

[0014] In an eleventh aspect, an apparatus is provided. The apparatus may include: components for acquiring a closed group identifier (ID) of a second cell during a handover of the device from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to either a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of the CSG or CAG; and components for sending a measurement report including the closed group ID of the second cell to the first access network.

[0015] In a twelfth aspect, an apparatus is provided. The apparatus may include: components for receiving a closed group identifier (ID) of a first cell from a first core network associated with the first access network during a handover of the device from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; components for obtaining from network functions a list of allowed closed group IDs associated with the other of the CSG or CAG based on the received closed group ID of the first cell; and components for transmitting the list of allowed closed group IDs to the second access network.

[0016] In a thirteenth aspect, a non-transitory computer-readable medium is provided, comprising program instructions that, when executed by a device, cause the device to perform at least the method according to any one of the fifth to eighth aspects described above.

[0017] In a fourteenth aspect, a computer program including instructions is provided, which, when executed by a device, cause the device to perform at least the method according to any one of the fifth to eighth aspects described above.

[0018] In a fifteenth aspect, a second core network is provided. The second core network includes: a receiving circuitry configured to receive, during a handover of a device from a first cell of a first access network to a second cell of a second access network, a first closed group identifier (ID) of the first cell from a first core network associated with the first access network, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), the second cell belongs to the other of the CSG or CAG, and the first closed group ID is associated with either the CSG or CAG; and a determining circuitry configured to determine, based on the first closed group ID, a second closed group ID associated with the other of the CSG ID or CAG ID.

[0019] In a sixteenth aspect, a first access network is provided. The first access network may include: a determining circuit system configured to determine a closed group ID of the second cell based on a cell identifier (ID) of the second cell during a handover of a device from a first cell of the first access network to a second cell of the second access network, wherein the first cell belongs to either a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of the CSG or CAG; and a transmitting circuit system configured to transmit the closed group ID of the second cell to a first core network.

[0020] In a seventeenth aspect, an apparatus is provided. The apparatus may include: an acquisition circuitry configured to acquire a closed group identifier (ID) of the second cell during a handover from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to either a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of the CSG or CAG; and a transmission circuitry configured to transmit a measurement report including the closed group ID of the second cell to the first access network.

[0021] In an eighteenth aspect, a second core network is provided. The second core network may include: a receiving circuitry configured to receive, during a handover of a device from a first cell of a first access network to a second cell of a second access network, a closed group identifier (ID) of a first cell associated with the first access network, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; an obtaining circuitry configured to obtain, based on the received closed group ID of the first cell, a list of allowed closed group IDs associated with the other of the CSG or CAG from network functions; and a transmitting circuitry configured to transmit the list of allowed closed group IDs to the second access network.

[0022] It should be understood that the summary portion is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0023] Some exemplary embodiments will now be described with reference to the accompanying drawings, in which:

[0024] Figure 1 The illustration shows an example of a network environment in which some embodiments of the present disclosure may be implemented;

[0025] Figure 2 The diagram illustrates the signaling process for UE handover from an LTE cell to a 5G cell;

[0026] Figure 3A The illustration shows an example signaling process for UE handover between an enhanced 5G CAG cell and an LTE CSG cell, according to some embodiments of the present disclosure;

[0027] Figure 3B The illustration shows an example signaling process for UE handover between an enhanced 5G CAG cell and an LTE CSG cell, according to some embodiments of the present disclosure;

[0028] Figure 4 The illustration shows an example signaling process for UE handover between an enhanced 5G CAG cell and an LTE CSG cell, according to some embodiments of the present disclosure;

[0029] Figure 5 The illustration shows an example signaling process for UE handover between an enhanced 5G CAG cell and an LTE CSG cell, according to some embodiments of the present disclosure;

[0030] Figure 6 The illustration shows an example signaling process for UE handover between an enhanced 5G CAG cell and an LTE CSG cell, according to some embodiments of the present disclosure;

[0031] Figure 7 The illustration shows an example signaling process for UE handover between an enhanced 5G CAG cell and an LTE CSG cell, according to some embodiments of the present disclosure;

[0032] Figure 8A The illustration shows an example signaling process for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure;

[0033] Figure 8B The illustration shows an example signaling process for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure;

[0034] Figure 9 The illustration shows an example signaling process for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure;

[0035] Figure 10 The illustration shows an example signaling process for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure;

[0036] Figure 11 The illustration shows an example signaling process for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure;

[0037] Figure 12 The illustration shows an example signaling process for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure;

[0038] Figure 13 The illustration shows a flowchart of an example method implemented at a second core network according to some other embodiments of the present disclosure;

[0039] Figure 14 The illustration shows a flowchart of an example method implemented at a first access network according to some other embodiments of the present disclosure;

[0040] Figure 15 The illustration shows a flowchart of an example method implemented at terminal device 110 according to some other embodiments of the present disclosure;

[0041] Figure 16 The illustration shows a flowchart of an example method implemented at a second core network according to some other embodiments of the present disclosure;

[0042] Figure 17 The illustration shows a simplified block diagram of an apparatus suitable for implementing some embodiments of the present disclosure; and

[0043] Figure 18 A block diagram illustrating an example of a computer-readable medium according to some embodiments of the present disclosure is shown.

[0044] Throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0045] The principles of this disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and implementing this disclosure, and do not constitute any limitation on the scope of this disclosure. The disclosure described herein can be implemented in various other ways besides those described below.

[0046] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0047] In this disclosure, references to "an embodiment," "embodiment," and "example embodiment," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, those skilled in the art will understand that, whether explicitly described or not, combining it with other embodiments to affect such a feature, structure, or characteristic is within the scope of their knowledge.

[0048] It should be understood that although the terms “first” and “second”, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0049] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. The singular forms “a,” “an,” and “the” used herein also include the plural forms unless the context clearly indicates otherwise. Further understanding is that the terms “comprising,” “including,” “having,” “containing,” and / or “comprise”, as used herein, specify the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. As used herein, “at least one of the following: ” and “<at least one of a list of two or more elements>” and similar wording (where a list of two or more elements is connected by “and” or “or”) means at least any one of these elements, or at least any two or more of these elements, or at least all of these elements.

[0050] As used in this application, the term "circuit system" may refer to one or more or all of the following: (a) Pure hardware circuit implementation (such as implementation using only analog and / or digital circuit systems), and (b) A combination of hardware circuitry and software, such as (if applicable): (i) A combination of (multiple) analog and / or digital hardware circuits and software / firmware, and (ii) Any part of a hardware processor (including (multiple) digital signal processors), software, and (multiple) memories, which work together to enable a device (such as a mobile phone or server) to perform various functions, and (c) (Multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or a portion thereof, which require software (e.g., firmware) to operate, but may be absent when operation is not required.

[0051] The definition of "circuit system" applies to all uses of the term in this application, including in any claim. As another example, as used in this application, the term "circuit system" also covers only hardware circuitry or a processor (or processors) or a portion of hardware circuitry or a processor and its accompanying software and / or firmware. For example, if applicable to a particular claim element, the term "circuit system" also covers baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0052] As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as Long Term Evolution (LTE), LTE-A Advanced (LTE-A), Wideband Code Division Multiplexing (WCDMA), High-Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. Furthermore, communication between terminal devices and network devices in a communication network can be performed according to any suitable generation of communication protocol, including but not limited to first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, future fifth-generation (5G) communication protocols, and / or any other protocols currently known or to be developed in the future. Embodiments of this disclosure can be applied to various communication systems. Given the rapid development of communications, there will naturally be communication technologies and systems of future types that can embody this disclosure. This should not be construed as limiting the scope of this disclosure to the systems described above.

[0053] As used herein, the term "network device" or "network" refers to a node in a communication network through which terminal devices access the network and receive services. A network device can refer to a base station (BS) or access point (AP), such as a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), an NR NB (also known as a gNB), a Remote Radio Unit (RRU), a Radio Header (RH), a Remote Radio Header (RRH), a relay, a low-power node (such as a femtosecond or picosecond), etc., depending on the terminology and technology used.

[0054] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not a limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). Terminal devices can include, but are not limited to, mobile phones, cellular phones, smartphones, Voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices (such as digital cameras), gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEE), laptop mounted devices (LME), USB dongles, smart devices, wireless customer premises equipment (CPE), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. In the following description, the terms "terminal equipment", "communication equipment", "terminal", "user equipment" and "UE" are used interchangeably.

[0055] As mentioned above, version 19 introduced a research project on femtocell support in 5G. In LTE femtocell networks, a CSG (Cellular Support Group) designates a set of authorized users who are permitted to access a specific CSG cell within the PLMN by specifying a CSG ID. A CSG cell is a cell that broadcasts one or more CSG IDs. The base station hosting the CSG cell is called the Home eNodeB (HeNB) or a 4G / LTE femtocell base station. That is, these cells are managed by the HeNB or 4G / LTE femtocell base station. Membership in the CSG is defined in the user subscription and UE settings. When a UE attempts to connect to a CSG cell, the network's mobility management entity verifies access rights based on subscription data; that is, it determines whether the UE is permitted to do so, taking into account the subscription data.

[0056] In 5G, CAG (Confirmation AG) serves a similar purpose: authorizing a specific subscriber to access a designated CAG cell associated with a CAG ID. In other words, a CAG identifier represents a group of subscribers who are authorized / permitted to access one or more CAG cells associated with a CAG ID. A CAG cell is a cell that broadcasts one or more CAG IDs. The base station hosting the CAG cell is called the Home gNode B (HgNB) or 5G femtocell. That is, these cells are managed by the Home gNode B (HgNB) or 5G femtocell. The CAG concept is similar to the CSG concept in LTE, but was initially introduced in the context of PNI-NPN to prevent (multiple) UEs that are not permitted to access the NPN via (multiple) associated cells from automatically selecting and accessing (multiple) associated CAG cells. CAG-based access control was introduced in 3GPP Release 16. That is, as described in 3GPP Release 16, similar to CSG, the CAG concept appears in the context of Public Network Integration of Non-Public Networks (PNI-NPN) to prevent unauthorized UEs from accessing associated CAG cells, thereby ensuring controlled network access. In this disclosure, it is assumed that the CAG concept defined for PNI-NPN is reused in 5G femtosecond deployments to achieve femtosecond access control in 5G. This assumption minimizes the workload in 3GPP and has been hinted at in research project proposals submitted to the SA, SA2, and RAN plenary meetings.

[0057] The proposed research project (SWS-230037) in version 19 regarding femtocell support within the 5G framework acknowledges the need to facilitate access for subscribers to 5G femtocells and to have access control managed by the CAG owner or authorized administrator. Integrating 5G femtocells into the existing ecosystem requires addressing the complexities of access control, potentially leveraging concepts such as the CSG Subscriber Server (CSS) from EPS (Evolved Packet System).

[0058] Introducing 5G femtocells in Release 19 requires consideration of mobility between LTE CSG cells and 5G CAG cells. This is particularly important as enterprises gradually extend 5G femtocell coverage to LTE femtocell deployments, necessitating a seamless handover mechanism for UEs switching between the two cell types. Therefore, enabling seamless mobility between LTE CSG cells and 5G CAG cells presents a challenge. With the gradual introduction of 5G femtocells into LTE femtocell deployments, a technical solution for smooth handover between CSG and CAG cells becomes crucial.

[0059] In view of the above discussion and analysis, a technical solution for improving or enhancing UE handover is provided, particularly a technical solution for enhancing the seamless handover mechanism for UE switching between two cellular types. In some example embodiments of this disclosure, a second core network receives a first closed group identifier (ID) of a first cell from a first core network associated with a first access network, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other CSG or CAG, and the first closed group ID is associated with either the CSG or CAG, and then the second core network also determines a second closed group ID associated with the other CSG ID or CAG ID based on the first closed group ID. In this way, the determined second closed group ID will be used by the target cell, and access control from the first cell to the second cell can be implemented by the second core network based on the second closed group ID and related subscription information.

[0060] For illustrative purposes, the principles and exemplary embodiments of this disclosure for enhancing UE handover will be described below. However, it should be noted that these embodiments are given to enable those skilled in the art to understand the inventive concept of this disclosure and implement the technical solutions presented herein, and not to limit the scope of this disclosure in any way.

[0061] Figure 1 An example network environment 100 in which exemplary embodiments of the present disclosure may be implemented is illustrated. Environment 100 (which may be part of a communication network) includes terminal devices and network devices. Figure 1 As shown, the communication network 100 may include a terminal device 110 (hereinafter also referred to as user equipment 110 or UE 110). The communication network 100 may also include a first access network 120 and a second access network 130. The terminal device 110 may establish radio links to the first access network 120 and the second access network 130 by using dual connectivity (DC) technology or multiple connectivity technology. The first access network 120 (hereinafter also referred to as the source access network) may be, for example, a serving base station or a source base station, and the serving cell is a cell configured by the network for the terminal device to perform uplink and downlink transmissions. The second access network 130 (hereinafter also referred to as the target access network) may be, for example, the target base station to which the UE 110 will connect. Operational frequency band changes or switching are achieved through a handover (HO) procedure. The HO procedure triggers a handover of both the UL and DL of the terminal device from the source access network to the target access network.

[0062] like Figure 1As shown, source access network 120 serves corresponding areas 120-1 and 120-2 (also referred to as cells 120-1 and 120-2, the portion of the source access network used to serve the corresponding areas is also referred to herein as a cell). These source cells (e.g., cells 120-1 and 120-2) can form one of a Closed Subscriber Group (CSG) and a Closed Access Group (CAG). Similarly, target access network 130 serves corresponding areas 130-1 and 130-2 (also referred to as cells 130-1 and 130-2) using different frequency bands of DL and UL. These target cells (e.g., cells 130-1 and 130-2) can form the other of a CSG and a CAG. That is, source cell 120-1 or 120-2 belongs to one of a CSG and a CAG, and target cell 130-1 or 130-2 belongs to the other of a CSG and a CAG.

[0063] like Figure 1 As shown, the communication network 100 may further include a first core network 140 for the source access network 120, and the first core network 140 may include elements 140-1 and 140-2. The communication network 100 may further include a second core network 150 for the target access network 130, and the second core network 150 may include elements 150-1 and 150-2. If the source access network 120 is an LTE CSG cell, the first core network 140 may include a Mobility Management Entity (MME) as element 140-1 and a Home Subscriber Server (HSS) as element 140-2; and if the target access network 130 is a 5G CAG cell, the second core network 150 may include an Access and Mobility Management Function (AMF) as element 150-1 and a Unified Data Management (UDM) as element 150-2, and vice versa. The N26 interface is the interface between the 4G core network and the 5G core network (between the MME and the AMF) and is used for 4G and 5G interoperability.

[0064] It should be understood that the number of network devices and terminal devices is for illustrative purposes only and does not represent any limitation. System 100 may include any suitable number of network devices and / or terminal devices suitable for implementing embodiments of this disclosure. Although not shown, it should be understood that one or more terminal devices may be located in environment 100.

[0065] Communication in network environment 100 may be implemented according to any suitable communication protocol(s), including but not limited to third-generation (3G), fourth-generation (4G), fifth-generation (5G) or higher, wireless local area network communication protocols (such as IEEE 802.11), and / or any other protocol currently known or to be developed in the future. Furthermore, communication may utilize any suitable wireless communication technology, including but not limited to: multiple-input multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), Bluetooth, ZigBee and machine-type communication (MTC), enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), ultra-reliable low-latency communication (URLLC), carrier aggregation (CA), dual connectivity (DC), and new radio unlicensed (NR-U) technologies.

[0066] In the following text, reference will be made to Figure 2 The signaling process for UE handover from an LTE cell to a 5G cell is described in section 200.

[0067] For discussion purposes, please refer to Figure 1 The process described in section 200 illustrates the stages of the single-registration-based interoperability process from EPS to 5GS.

[0068] like Figure 2 As shown, in step 1, the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) initiates a handover. In step 2, the E-UTRAN sends a handover request message to the MME. In step 3, the MME sends a forwarding relocation request message to the Initial AMF via the N26 interface. In step 4, the Initial AMF invokes the Session Management Function (SMF). Nsmf_PDUSession_ CreateSMContext Service operation (UE Evolved Packet System (EPS) Packet Data Network (PDN) connection, initial AMFID, data forwarding information, target ID), and indication of HO preparation indication (to avoid handover UP path). The initial AMF ID uniquely identifies the initial AMF serving the UE.

[0069] In step 5, if a dynamic PCC is deployed, the SMF+PGW (PDN gateway)-C (for home routing scenarios, via the default V-SMF of H-SMF) can initiate an SMF-initiated SM policy modification to the Policy Control Function (PCF). In step 6, the SMF+PGW-C requests the PGW-U+UPF (User Plane Function) to allocate CN tunnel information for the PDU session. In step 7, the SMF+PGW-C sends a message to the initial AMF. Nsmf_PDUSession_CreateSMContextResponse. In step 8, only for home route roaming scenarios, the default V-SMF selects the default V-UPF and initiates the N4 session establishment process using the selected default V-UPF. In step 8a, based on the S-NSSAI received from SMF+PGW-C, the initial AMF can reselect the target AMF and call the selected target AMF. Namf_Communication_CreateUEContext ask.

[0070] At step 9, the target AMF sends a handover request message to the NG-RAN (Next Generation RAN). At step 10, the NG-RAN sends a handover request confirmation message to the target AMF. At step 11, the target AMF sends a handover request confirmation message to the SMF. Nsmf_PDUSession_ UpdateSMContext A request message is sent to update the N3 tunnel information. In step 12, if the NG-RAN accepts the N2 handover, the SMF+PGW-C performs preparations for the N2 handover by indicating the NG-RAN's N3 UP address and tunnel ID to the UPF. In step 13, the SMF+PGW-C sends a request message to the target AMF. Nsmf_PDUSession_UpdateSMContext Response. At step 13a, the target AMF calls the initial AMF. Namf_Communication_CreateUEContext Response (Reason). In step 14, the target AMF sends a "Forward Relocation Response" message to the MME. In step 15, it requests a response to create an indirect data forwarding tunnel between the MME and the SGW (Serving Gateway).

[0071] In Process 200, the challenges of switching between LTE and 5G networks, particularly the transition between CSG and CAG cells (e.g., from an LTE CSG cell to a 5G CAG cell and vice versa), revealed some issues.

[0072] Regarding the first issue, a significant problem arises during N26-based handover when a UE migrates from an LTE CSG cell to a 5G CAG cell: the target AMF lacks knowledge of the target NR cell's CAG ID and the list of CAG IDs subscribed to by the UE. This lack of information hinders the target AMF's ability to perform effective access control measures. In other words, during N26-based handover, when a UE moves from an LTE CSG cell to a 5G CAG cell, the target AMF will be unaware of the target NR cell's CAG ID and the list of subscribed CAG IDs, thus preventing it from performing access control.

[0073] Regarding the second issue, a significant challenge arises when transitioning from a 5G CAG cell to an LTE CSG cell. The mechanism for inferring CSG-related information from the CAG details provided within the EPS is unclear. This knowledge gap hinders the EPS's ability to extract key CSG-specific data from given CAG data during handover. In other words, in the case of handover from a 5G CAG cell to an LTE CSG cell, it is unknown how the EPS infers CSG information from the provided CAG information.

[0074] In the following text, reference will be made to Figure 3A Example signaling procedures 300A, according to some embodiments of this disclosure, are described for enhancing UE handover between 5G CAG cells and LTE CSG cells and resolving at least some of the problems mentioned above. For discussion purposes, reference may be made to... Figure 3A To describe process 300A. Process 300A may involve, for example: Figure 1 The terminal device 110, the first or source access network 120, the first core network 140 (e.g., element 140-1), and the second core network 150 (e.g., element 150-1) are shown. It should be understood that, although in Figure 1 The process 300A is described in the communication environment 100, but the same process can be applied to other communication scenarios with similar problems.

[0075] In process 300A, it should be noted that if the cell of the source access network 120 belongs to either CSG or CAG, then the cell of the target access network 130 belongs to the other CSG or CAG. If the cell of the source access network 120 belongs to CSG, then the first core network 140 used for the source access network 120 may include MME, and the second core network 150 used for the target access network 130 may include AMF. Conversely, if the cell of the source access network 120 belongs to CAG, then the first core network 140 used for the source access network 120 includes AMF, and the second core network 150 used for the target access network 130 may include MME.

[0076] It should be noted that process 300A is performed during the handover phase for terminal device 110 from a first cell (e.g., cell 120-1, also known as the source cell) of the first access network 120 to a second cell (e.g., cell 130-1, also known as the target cell) of the second access network 130.

[0077] like Figure 3AAs shown, in process 300A, the measurement report reported by the UE will include the closed group ID of the target cell. Specifically, terminal device 110 obtains (305) the closed group identifier (ID) of the second cell 130-1. If the second cell 130-1 is a 5G CAG cell, the closed group ID is the CAG ID, and if the second cell 130-1 is a 4G CSG cell, the closed group ID is the CSG ID. That is, the first cell 120-1 belongs to either CSG or CAG, and the second cell 130-1 belongs to the other CSG or CAG. In some embodiments, terminal device 110 decodes the 5G SIB1 broadcast message received from the second access network 130 to read the CAG-ID of the target cell 130-1, and includes the CAG ID and other relevant information in the measurement report.

[0078] Then, terminal device 110 sends (310) a measurement report including the closed group ID of second cell 130-1 to first access network 120. First access network 120 receives (315) the measurement report including the closed group ID of second cell 130-1. Then, first access network 120 sends (320) the measurement report including the closed group ID of second cell 130-1 to first core network 140 (e.g., element 140-1) via a handover request message. First core network 140 (e.g., element 140-1) receives (325) the closed group ID of second cell 130-1 via a handover request message. Then, first core network 140 (e.g., element 140-1) sends (330) the closed group ID of second cell 130-1 to second core network 150 (e.g., element 150-1) via a forwarding relocation request message. That is, the closed group ID of second cell 130-1 is available in the forwarding relocation request message.

[0079] Then, the second core network 150 (e.g., element 150-1) performs access control based on the closed group ID of the second cell 130-1 and subscription information 110 associated with another item in the CSG or CAG. For example, if the target cell 130-1 is a 5GCAG cell, the second core network 150 will include an AMF, and the AMF can perform CAG cell access control based on the target cell's CAG ID and CAG-related subscription information 110 (e.g., a list of allowed CAG IDs of the terminal device 110). The CAG-related subscription information 110 can be obtained from element 150-2 (e.g., UDM) of the second core network 150.

[0080] By including the target cell's closed group ID (e.g., CAG ID or CSG ID) in the measurement report and reporting that ID to the core network, the corresponding core network of the target cell can know the target cell's closed group ID. For example, the AMF for a 5G CAG cell can know the CAG ID of the target 5G CAG or NR cell and can also obtain a list of subscribed CAG IDs from the UDM. Alternatively, the MME for an LTE CSG cell can know the CSG ID of the target LTE CSG cell and can also obtain a list of subscribed CSG IDs from the HSS. Based on both the CAG ID and CAG-related subscription data, the AMF can perform access control for the 5G NR target cell, or based on the CSG ID and CSG-related subscription data, the MME can perform access control for the LTE target cell.

[0081] In the following text, reference will be made to Figure 3B Example signaling procedures 300B, according to some embodiments of this disclosure, are described for enhancing UE handover between 5G CAG cells and LTE CSG cells and resolving at least some of the problems mentioned above. For discussion purposes, reference may be made to... Figure 3B To describe process 300B. Process 300B may involve, for example: Figure 1 The terminal device 110, the first or source access network 120, and the first core network 140 (e.g., the first element 140-1) are shown.

[0082] In process 300B, it should be noted that if the cell of the source access network 120 belongs to one of the CSG and CAG, then the cell of the target access network 130 belongs to the other of the CSG and CAG. It should also be noted that process 300B is performed during the handover phase of the terminal device 110 from the first cell of the first access network 120 (e.g., cell 120-1, also referred to as the source cell) to the second cell of the second access network 130 (e.g., cell 130-1, also referred to as the target cell).

[0083] The following describes the differences between process 300A and process 300B. Access control is performed by the first core network based on the closed group ID and related subscription information of the second cell (345), instead of... Figure 3A The operation shown is performed by the second core network.

[0084] When the closed group ID of the second cell is received from the first access network 120, the first core network 140 (e.g., element 140-1) can retrieve subscription information from the combined User Data Management (UDM) and Home Subscriber Server (HSS). For example, if the first cell or source cell is a CSG cell and the second cell or target cell is a CAG cell, when the CAG ID of the target cell (which is included in the UE's measurement report) is received from the source eNB, the MME associated with the source eNB can also retrieve CAG-related subscription information (e.g., a list of allowed CAG IDs, one or more CAG IDs, etc.) from the combined UDM and HSS, and then perform access control based on the received CAG ID and the retrieved CAG-related subscription information. Alternatively, if the first cell or source cell is a CAG cell and the second cell or target cell is a CSG cell, when the CSG ID of the target cell (which is included in the UE's measurement report) is received from the source gNB, the AMF associated with the source gNB can also retrieve CSG-related subscription information (e.g., a list of allowed CSG IDs) from the combined UDM and HSS, and then perform access control based on the received CSG ID and the retrieved CSG-related subscription information.

[0085] In this process 300B, a combined UDM and HSS are used, and subscription information is retrieved from the combined UDM and HSS. When the closed group ID of the second cell and the relevant subscription information from the combined UDM and HSS are received, access control is performed directly by the first core network without transmitting the closed group ID of the second cell to the second core network.

[0086] In the following text, reference will be made to Figure 4 Example signaling procedures 400, according to some embodiments of this disclosure, are described for enhancing UE handover between 5G CAG cells and LTE CSG cells and resolving at least some of the problems mentioned above. For discussion purposes, reference may be made to... Figure 4 The description is from process 400. Process 400 may involve, for example, Figure 1 The terminal device 110, the first or source access network 120, and the first core network 140 (e.g., element 140-1) are shown.

[0087] In process 400, it should be noted that if the cell of the source access network 120 belongs to one of the CSG and CAG, then the cell of the target access network 130 belongs to the other of the CSG and CAG. It should also be noted that process 400 is performed during the handover phase for terminal device 110 from a first cell (e.g., cell 120-1, also referred to as the source cell) of the first access network 120 to a second cell (e.g., cell 130-1, also referred to as the target cell) of the second access network 130.

[0088] like Figure 4 As shown, in process 400, terminal device 110 acquires (405) the first closed group identifier (ID) of the second cell 130-1. In some embodiments where the target cell is a 5G NR cell, the first closed group ID is the CAG ID of the second cell, and terminal device 110 decodes the 5G SIB1 broadcast message received from the second access network 130 to read the CAG-ID of the target cell 130-1 and includes the CAG ID in the measurement report. In some embodiments where the second cell is a 4G LTE cell, the first closed group ID is the CSG ID of the second cell.

[0089] Then, terminal device 110 sends (410) a measurement report including the first closed group ID of the second cell 130-1 to first access network 120. First access network 120 receives (415) the measurement report including the first closed group ID of the second cell 130-1. Then, first access network 120 sends (420) the first closed group ID of the second cell 130-1 to first core network 140 (e.g., element 140-1) via a handover request message. First core network 140 (e.g., element 140-1) receives (425) the first closed group ID of the second cell 130-1 via a handover request message.

[0090] In this process 400, the first core network 140 (e.g., element 140-1) determines (430) the second closed group ID of the second cell based on the first closed group ID of the second cell. Then, the first core network 140 (e.g., element 140-1) performs (435) access control based on the determined second closed group ID and subscription information.

[0091] Assuming the CAG ID and CSG ID in the UE subscription information are allocated according to the same rules—that is, the CAG and CSG subscription information are consistent, for example, the CAG ID and CSG ID are allocated from the same value pool and follow the same semantics—the MME (based on CSG subscription information) can perform CAG-based access control for the target NR cell by identifying the CSG and CAG information. For example, it can be assumed that the target CAG ID is the same as the source CSG ID, or that the target CAG ID can be known via a configuration table that maps the target NR cell ID to the CAG ID. Therefore, during handover from the source CSG cell to the target CAG cell, the MME can directly use the CAG ID of the target cell reported by the UE to convert or map the CAG ID to the CSG ID according to the allocation rules, and then the MME can use the subscription data for the CSG to perform target cell access control. Alternatively, during a handover from the source CAG cell to the target CSG cell, the AMF can directly use the CSG ID of the target cell reported by the UE to convert or map the CSG ID to the CAG ID according to rules, and then the AMF can use the subscription data for the CAG to perform target cell access control.

[0092] In this process, by assigning CAG ID and CSG ID according to the same rules, it is not necessary to transmit the CAG ID of the target cell reported in the measurement report from the MME to the AMF, or it is not necessary to transmit the CSG ID of the target cell reported in the measurement report from the AMF to the MME.

[0093] In the following text, reference will be made to Figure 5 Example signaling procedures 500, according to some embodiments of this disclosure, are described for enhancing UE handover between 5G CAG cells and LTE CSG cells and resolving at least some of the problems mentioned above. For discussion purposes, reference may be made to... Figure 5 To describe process 500. Process 500 may involve, for example, Figure 1 The first core network 140 (e.g., element 140-1) and the second core network 150 (e.g., element 150-1) are shown.

[0094] In process 500, it should be noted that if the cell of the source access network 120 belongs to either the CSG or the CAG, then the cell of the target access network 130 belongs to the other CSG or the CAG. That is, element 140-1 of the first core network 140 is either the MME or the AMF, and element 150-1 of the second core network 150 is the other MME or the AMF. It should be noted that process 500 is performed during the handover phase for terminal device 110 from the first cell (e.g., cell 120-1, also referred to as the source cell) of the first access network 120 to the second cell (e.g., cell 130-1, also referred to as the target cell) of the second access network 130.

[0095] In this process 500, the measurement report reported by the UE will not include the target cell's closed group ID, but will include the source cell's closed group ID. For example, currently, the MME in... Forwarding Relocation Request The message sends a CSG ID, but this CSG ID is ignored by the AMF because this feature is not yet supported in the specification. However, in process 500, for example, the AMF will obtain the CAG ID based on the received CSG ID. Specifically, the first core network 140 (e.g., element 140-1) communicates via the N26 interface, for example, via... Forwarding Relocation Request message Send (505) the first closed group ID of the first cell associated with either the CSG ID or the CAG ID to the second core network. For example, the MME can do so via... Forwarding Relocation Request Message The source cell's CSG ID is sent to the AMF, or the AMF may send the source cell's CAG ID to the MME via the N26 interface. The second core network 150 (e.g., element 150-1) receives (510) the first closed group ID of the first cell. The second core network 150 (e.g., element 150-1) then determines (515) a second closed group ID associated with the other of the CSG ID or CAG ID based on the first closed group ID. In this process, it is assumed that the target cell will use the determined second closed group ID. For example, the AMF may determine the CAG ID that the target cell will use based on the received CSG ID of the source cell, and alternatively, the MME may determine the CSG ID that the target cell will use based on the received CAG ID of the source cell.

[0096] In some embodiments, the second core network 150 (e.g., element 150-1) maps the first closed group ID to a second closed group ID used by the second cell based on at least one operator-specific policy. In some embodiments, the second core network 150 (e.g., element 150-1) obtains the second closed group ID mapped to the first closed group ID from an element or network function 150-2 (e.g., UDM or HSS).

[0097] Then, the second core network 150 (e.g., element 150-1) performs (520) access control for the terminal equipment of the second cell based on the second closed group ID and subscription information associated with another item in the CSG or CAG. The subscription information can be obtained from element 150-2 of the second core network 150.

[0098] In this process, for example, the UE's measurement report does not include the CAG ID of the target cell (e.g., a 5G NR cell), but includes the CSG ID of the source cell (e.g., an LTE cell). The CAG ID is determined based on the received CSG ID (e.g., by mapping the CSG ID to a CAG ID according to certain operator policies), and assuming the target cell uses the mapped CAG ID, the AMF can know the target cell's CAG ID through this mapping. The AMF can then perform access control based on the mapped CAG ID and CAG-related subscription data.

[0099] In the following text, reference will be made to Figure 6 Example signaling procedures 600, according to some embodiments of this disclosure, are described for enhancing UE handover between 5G CAG cells and LTE CSG cells and resolving at least some of the problems mentioned above. For discussion purposes, reference may be made to... Figure 6 To describe process 600. Process 600 may involve, for example, Figure 1 The first access network 120, the first core network 140 (e.g., element 140-1), and the second core network 150 (e.g., element 150-1) are shown.

[0100] In process 600, it should be noted that if the cell of the source access network 120 belongs to either the CSG or the CAG, then the cell of the target access network 130 belongs to the other CSG or the CAG. That is, element 140-1 of the first core network 140 is either the MME or the AMF, and element 150-1 of the second core network 150 is the other MME or the AMF. It should be noted that process 600 is performed during the handover phase for terminal device 110 from the first cell (e.g., cell 120-1, also referred to as the source cell) of the first access network 120 to the second cell (e.g., cell 130-1, also referred to as the target cell) of the second access network 130.

[0101] In this process 600, the measurement report reported by the UE will not include the closed group ID of the target cell, but will include the closed group ID of the source cell. However, in this process 600, for example, the CAG ID of the target 5G NR cell can be obtained at the first access network, or the CSG ID of the target LTE cell can be obtained at the first access network. Specifically, the first access network 120 determines (605) the closed group ID of the second cell based on the cell identifier (ID) of the second cell. For example, the first access network 120 (e.g., the source eNB) can determine the CAG ID of the 5G NR target cell based on the target cell ID reported by the UE. Alternatively, the first access network 120 (e.g., the source gNB) can determine the CSG ID of the LTE target cell based on the target cell ID reported by the UE. In some embodiments, the first access network 120 maps the cell ID of the second cell to the closed group ID of the second cell based on a configuration table.

[0102] Then, the first access network 120 sends (610) the closed group ID of the second cell to the first core network 140 (e.g., element 140-1). The first core network 140 (e.g., element 140-1) receives (615) the closed group ID of the second cell, and then the first core network 140 (e.g., element 140-1) sends (620) the closed group ID of the second cell to the second core network 150 (e.g., element 150-1), and then the second core network 150 (e.g., element 150-1) receives (625) the closed group ID of the second cell. Then, the second core network 150 (e.g., element 150-1) performs (630) access control based on the closed group ID of the second cell and subscription information.

[0103] In this process, for example, the CAG ID of the target 5G NR cell can be determined by the source access network by mapping the target cell ID to the CAG ID. Then, the AMF will know the CAG ID of the target 5G NR cell and can perform CAG access control based on the target cell's CAG ID and CAG-related subscription data. Similarly, the CSG ID of the target LTE cell can be determined by the source access network by mapping the target cell ID to the CSG ID. Then, the MME will know the CSG ID of the target LTE cell and can perform CSG access control based on the target cell's CSG ID and CSG-related subscription data.

[0104] In the following text, reference will be made to Figure 7 Example signaling procedures 700, according to some embodiments of this disclosure, are described for enhancing UE handover between 5G CAG cells and LTE CSG cells and resolving at least some of the problems mentioned above. For discussion purposes, reference may be made to... Figure 7To describe process 700. Process 700 may involve, for example: Figure 1 The first core network 140 (e.g., element 140-1), the second core network 150 (e.g., element 150-1), and the second access network 130 are shown.

[0105] In process 700, it should be noted that if the cell of the source access network 120 belongs to either the CSG or the CAG, then the cell of the target access network 130 belongs to the other CSG or the CAG. That is, element 140-1 of the first core network 140 is either the MME or the AMF, and element 150-1 of the second core network 150 is the other MME or the AMF. It should be noted that process 700 is performed during the handover phase for terminal device 110 from the first cell (e.g., cell 120-1, also referred to as the source cell) of the first access network 120 to the second cell (e.g., cell 130-1, also referred to as the target cell) of the second access network 130.

[0106] In this process 700, the measurement report reported by the UE will not include the closed group ID of the target cell, but will include the closed group ID of the source cell. However, the second access network or the target access network knows the CAG ID of the target cell. The second access network or the target access network can perform access control based on the CAG ID of the target cell. Specifically, the first core network 140 (e.g., element 140-1) sends (705) the closed group ID of the first cell associated with either the CSG ID or the CAG ID to the second core network 150 (e.g., element 150-1) via the N26 interface. The second core network 150 (e.g., element 150-1) receives (710) the closed group ID of the first cell.

[0107] Then, based on the received closed group ID of the first cell, the second core network 150 (e.g., element 150-1) obtains (715) a list (e.g., one or more allowed closed group IDs) of the terminal device associated with another item in the CSG or CAG from its element or network function 150-2. The AMF receives the CSG ID from the MME and waits to perform access control until the UE performs a mobility registration update after the HO is performed. For example, the AMF obtains a list (e.g., one or more CAG IDs) of the allowed CAG IDs of the terminal device 110 from the UDM, and the MME obtains a list of the allowed CSG IDs of the terminal device 110 from the HSS. Then, the second core network 150 (e.g., element 150-1) sends (720) the list of allowed closed group IDs to the second access network 130. The second access network 130 performs (730) access control for the terminal device of the second cell based on the closed group ID of the second cell and the list of allowed closed group IDs. For example, the eNB performs CSG cell access control based on the CSG ID of the second cell and a list of allowed CSG IDs, or the gNB performs CAG cell access control based on the CAG ID of the second cell and a list of allowed CAG IDs. It should be noted that the second core network 150 (e.g., element 150-1) may also perform (735) access control based on the closed group ID of the second cell and an acquired list of allowed closed group IDs, instead of sending the list of allowed closed group IDs to the second access network 130 and performing access control there.

[0108] In this process, by sending the list of allowed CSG IDs or CAG IDs directly to the target access network, the target access network can perform access control based on the received list of allowed CSG IDs or CAG IDs and based on its own CSG ID or CAG ID.

[0109] In the following text, reference will be made to Figures 8 to 9. Figure 12 Example signaling procedures 800 to 1200 for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of this disclosure, are described. In these procedures, it is assumed that the terminal device or UE 110 has both 4G and 5G capabilities. It should be noted that during the application of procedures 800 to 1200, Figure 2 The relevant steps 0 to 2 and 4 to 16 described in TS 23.502 will remain unchanged. Figure 4 As described in .11.1.2.2.2-1, in step 10, NG-RAN anticipates not rejecting a handover to a femtospecific CAG cell at the target gNB on the grounds of handover failure. Furthermore, it should be noted that procedures 800 to 1200 apply to both intra-PLMN and inter-PLMN roaming scenarios.

[0110] for Figure 2 Step 3 as described in [the document], currently, MME is in [the context of this]. Forwarding Relocation Request The message includes the CSG ID, but this CSG ID is ignored by the AMF because this feature is not yet supported in the specification. Upon receiving a message containing the CSG ID from the MME... Forwarding Relocation Request At the same time, at least some of processes 800 to 1200 can be applied to step 3. These processes 800 to 1200 support different deployment requirements.

[0111] In the following text, reference will be made to Figure 8A This document describes an example signaling procedure 800A for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure.

[0112] like Figure 8A As shown, at step 0, UE 110 sends a message with CSG-ID to the EPS (eNB). UEMeasurementReport The message, where the eNB is an example of the first access network 120. As step 1, UE 110 moves to the vicinity of 5G-NR, where 5G-NR is an example of the second access network 130. In this step, UE 110 decodes the 5GSIB1 broadcast message received from 5G-NR to read the CAG-ID of the target cell, and then UE 110 includes the CAG-ID and related information, and uses the CAG-ID and related information as... UEMeasurementReport Part of the message, and sent to the eNB UEMeasurementReport The message. Then, the eNB, based on the data received from the UE... UEMeasurementReport This determines whether to trigger the HO.

[0113] In step 2, the eNB, through the UE, from UEMeasurementReport The target cell CAG-ID received in the middle is sent to the MME. Switching requirements Message. Then, in step 3, by sending via N26, which includes the target cell CAG-ID. change Send relocation request message and send to AMF Forwarding Relocation Request The message states that the MME is an example of element 140-1 in the first core network 140, and the AMF is an example of element 150-1 in the second core network 150. At step 4, the AMF queries the UDM. MobilityRestrictionList , MobilityRestrictionList This includes a list of allowed CAG IDs for the UE, such as one or more CAG IDs. Then, at step 5, the AMF is based on... MobilityRestrictionList(e.g., a list of allowed CAG IDs for the UE) and the received CAG ID of the target cell are used to perform CAG-based cell access control. For example, at step 6, if the AMF accepts the handover request from the MME, the handover to the target cell (5G-NR) is allowed; otherwise, the AMF rejects the handover request using an appropriate rejection code (e.g., access not allowed, etc.). The UE handover is then complete and served by both 5G-NR and the AMF (5GS). It should be noted that this procedure applies to both intra-PLMN and inter-PLMN roaming scenarios.

[0114] In signaling procedure 800A, the UE reports the target cell's CAG information to the source eNB via the UE measurement report. This requires updating the measurement report to include the CAG information. The eNB provides the target cell's CAG information to the MME, and the MME sends this data to the AMF in forwarding the relocation request. The AMF then uses this data based on information obtained from the UDM. MobilityRestrictionList The CAG ID received from the target cell is used to perform CAG-based access control.

[0115] In the following text, reference will be made to Figure 8B This document describes an example signaling procedure 800B for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure.

[0116] The differences between procedures 800A and 800B are described below. In procedure 800B, access control is performed by the MME based on the received CAG ID of the target CAG cell and CAG-related subscription information obtained from the combined UDM and HSS. For example, at step 3, the MME retrieves subscription information from the combined UDM and HSS, and at step 4, the MME performs access control for the target cell based on the received CAG ID and the subscription information retrieved from the combined UDM and HSS. Then, at step 5, the handover is accepted or rejected.

[0117] In this process 800B, a combined UDM and HSS are used, and the MME retrieves subscription information from the combined UDM and HSS. For example, when the CAG ID of the target cell (which is included in the measurement report) is received from the source eNB, the MME can directly retrieve the CAG-related subscription information (e.g., a list of allowed CAG IDs, which is part of the subscription information) from the combined UDM and HSS, and then perform access control based on the list of CAG IDs, instead of transmitting the target cell's CAG ID to the AMF and then performing access control at the AMF.

[0118] In the following text, reference will be made to Figure 9This document describes an example signaling procedure 900 for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure.

[0119] like Figure 9 As shown, at step 0, UE 110 sends a data entry with CAG-ID to the EPS (eNB). UEMeasurementReport In step 0, UE 110 sends a message with CSG-ID to the EPS (eNB). UEMeasurementReport The message, where the eNB is an example of the first access network 120. As step 1, UE 110 moves to the vicinity of 5G-NR, where 5G-NR is an example of the second access network 130. In this step, UE 110 decodes the 5GSIB1 broadcast message received from 5G-NR to read the CAG-ID of the target cell, and then UE 110 includes the CAG-ID and related information, and uses the CAG-ID and related information as... UEMeasurementReport Part of the message, and sent to the eNB UEMeasurementReport The message. Then, the eNB, based on the data received from the UE... UEMeasurementReport This determines whether to trigger the HO.

[0120] The differences between Procedure 800A and Procedure 900 are described below. In Procedure 900, it is assumed that the CAG ID and CSG ID in the UE subscription information are assigned according to the same rules. That is, the CAG and CSG subscription information are consistent; for example, the CAG ID and CSG ID are assigned from the same value pool and follow the same semantics. Therefore, the MME can directly use the CAG ID reported by the UE to convert or map the CAG ID to a CSG ID according to the allocation rules. The MME can use the access control rules for CSGs to perform target cell access control. That is, based on the CSG subscription information (including the UE's list of allowed CSG IDs obtained from the HSS, e.g., one or more CSG IDs), the MME can perform CAG-based access control for the target NR cell by identifying the CSG ID information and CAG ID information. The MME can decide whether to allow access, and if the CAG ID can be converted to a CSG ID, the MME will use the existence of the converted CSG ID in the list of allowed CSG IDs as the basis for access acceptance or access rejection.

[0121] In some embodiments, it may be assumed that the target CAG ID is the same as the source CSG ID. In some implementations, the target CAG may be known via a configuration table that maps the target NR cell ID to the CAG ID, and the CAG ID may then be converted to the CSG ID according to rules.

[0122] In the following text, reference will be made to Figure 10 This document describes an example signaling procedure 1000 for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of the present disclosure. In this procedure, the UE will not decode the 5GSIB1 broadcast message received from 5G-NR, and therefore will not include the CAG ID of the target cell in the measurement report, and thus will not need to update the measurement report normally sent by the UE.

[0123] like Figure 10 As shown, in step 1, the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) initiates a handover, and the E-UTRAN can be an example of a source eNB or the first access network 120. In step 2, the E-UTRAN sends a handover request message to the MME, and the MME can be an example of element 140-1 of the first core network 140. In step 3, the MME sends a forwarding relocation request message to the initial AMF via the N26 interface, and the initial AMF can be an example of element 150-1 of the second core network 150. If the UE's source cell is a CSG cell, the forwarding relocation request message can include CSG-related information of the source cell (such as the CSG ID). That is, in the forwarding relocation request message from the MME to the AMF in step 3, the source cell CSG ID is provided to the AMF, and therefore the CSG ID is available information in the forwarding relocation request message.

[0124] At step 3a, upon receiving CSG-related information (such as the CSG ID) from the source cell, the AMF can determine CAG-related information (such as the CAG ID) based on the source cell's CSG-related information. In some embodiments, the AMF maps the received CSG ID to the corresponding CAG ID based on operator-specific policies. These policies can be configured by the operator via network management within the AMF. In some embodiments, the AMF can retrieve the mapped CAG ID associated with the received CSG ID from another network function (such as the UDM). The AMF can be configured with information about when or how to retrieve data from the UDM, for example, based on the target cell or target gNB.

[0125] In this process 1000, it is assumed that the target NR cell uses a mapped CAG ID. If the policy does not allow mapping a CSG ID to a CAG ID, the handover will be rejected; or if the CSG ID cannot be mapped to a CAG ID due to the mapping algorithm, the handover will be rejected.

[0126] Then, at step 3b, upon receiving CSG-related information (such as the CSG ID) from the source cell, the AMF can be triggered to retrieve CAG subscription data (e.g., a list of CAG IDs allowed by the UE) from the UDM. If the mapped CAG ID is included in the list of allowed CAG IDs, the AMF will allow a handover to the target cell using the mapped CAG ID. Otherwise, if the mapped CAG ID is not included in the list of allowed CAG IDs, the AMF will reject the handover request to the target cell using an appropriate (e.g., correct) rejection code. In other words, the AMF performs access control based on the mapped CAG ID and CAG-related subscription data retrieved in step 3b (e.g., a list of allowed CAG IDs for the UE, which is part of a mobility restriction list). If the UE is a member of the target cell's CAG, meaning the UE is allowed to access the target cell according to the subscription data (e.g., the mobility restriction list), or the mapped CAG ID is in the list of allowed CAG IDs for the UE, then the HO should be allowed to proceed; otherwise, the HO will be rejected.

[0127] In the following text, reference will be made to Figure 11 An example signaling procedure 1100 for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of this disclosure, is described. In this procedure, the UE will not decode the 5GSIB1 broadcast message received from 5G-NR, and therefore will not include the CAG ID of the target cell in the measurement report, and thus will not need to update the measurement report normally sent by the UE.

[0128] like Figure 11 As shown, at step 1, the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) performs the handover initiation, and the E-UTRAN can be an example of a source eNB or a first access network 120. The source eNB may have a table configured to allow the source eNB to map the target NR cell ID reported by the UE to a CAG ID.

[0129] In step 2, the E-UTRAN sends a handover request message including the mapped CAG ID to the MME, and the MME can be an example of element 140-1 of the first core network 140. In step 3, the MME sends a forwarding relocation request message including the mapped CAG ID to the initial AMF via the N26 interface, and the initial AMF can be an example of element 150-1 of the second core network 150. Therefore, the forwarding relocation request message sent in step 3 can include CAG-related information (such as the CAG ID) of the target cell.

[0130] Then, at step 3a, the AMF obtains CAG subscription data (e.g., a list of allowed CAG IDs for the UE) from the UDM. If the mapped CAG ID obtained from the source eNB is included in the list of allowed CAG IDs, the AMF will allow a handover to the target cell using the mapped CAG ID. Otherwise, if the mapped CAG ID is not included in the list of allowed CAG IDs, the AMF will reject the handover request to the target cell using an appropriate rejection code. In other words, the AMF performs access control based on the mapped CAG ID determined by the source eNB and the CAG-related subscription data retrieved in step 3a (e.g., a list of allowed CAG IDs for the UE, which is part of a mobility restriction list). As used herein, a list of items (e.g., CAG IDs) refers to one or more items.

[0131] In the following text, reference will be made to Figure 12 An example signaling procedure 1200 for enhancing UE handover from an LTE CSG cell to a 5G CAG cell, according to some embodiments of this disclosure, is described. In this procedure, the UE will not decode the 5GSIB1 broadcast message received from 5G-NR, and therefore will not include the CAG ID of the target cell in the measurement report, and thus will not need to update the measurement report normally sent by the UE.

[0132] like Figure 12 As shown, in step 1, the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) initiates a handover, and the E-UTRAN can be an example of a source eNB or the first access network 120. In step 2, the E-UTRAN sends a handover request message to the MME, and the MME can be an example of element 140-1 of the first core network 140. In step 3, the MME sends a forwarding relocation request message to the initial AMF via the N26 interface, and the initial AMF can be an example of element 150-1 of the second core network 150. If the UE source cell is a CSG cell, the forwarding relocation request message can include CSG-related information of the source cell (such as the CSGID). That is, in the forwarding relocation request message from the MME to the AMF in step 3, the source cell CSG ID is provided to the AMF, and therefore the CSG ID is available information in the forwarding relocation request message.

[0133] In step 3a, upon receiving CSG-related information (such as the CSG ID) from the source cell, the AMF can be triggered to retrieve CAG-related subscription data from the UDM as part of the mobility restriction list, and then the AMF can retrieve the list of allowed CAG IDs of the UE from the CAG-related subscription data. That is, the list of allowed CAG IDs of the UE can be part of the mobility restriction list retrieved in step 3a. Then, in step 3b, the AMF provides the list of allowed CAG IDs to the target gNB. Based on the received list of allowed CAG IDs and the target gNB's CAG ID, the target gNB will perform CAG cell access control.

[0134] It should be noted that procedures 800 and 1000 to 1200 can also be applied to handovers from 5G NR cells to 4G LTE cells. In a handover from a 5G NR cell to a 4G LTE cell, the source cell is a 5G NR cell, and the target cell is a 4G LTE cell. The MME and AMF are swapped, and the UDM and HSS are swapped. In procedure 800, the UE reports the CSG ID of the target cell to the source gNB via a measurement report. In procedures 1000 to 1200, the UE reports the CAG ID of the source cell to the source gNB via a measurement report.

[0135] Constraints in current 4G specifications may include the exclusion of CAG information from measurement reports for NR cells by UEs served by eNBs, and the lack of understanding of 5G Mobility and Access Restriction Lists (MRLs) by 4G systems, which affects the ability of 4G systems to determine the compatibility between CAG cells and UE mobility restrictions.

[0136] Considering the constraints described above, procedures 800 to 1200 are designed to enable seamless mobility for the UE between LTE CSG cells and 5G CAG cells. For MME behavior: The MME transmits source CSG cell information to the 5G system during N26-based handover, as described in procedures 800 to 1200. For AMF behavior: Upon receiving a handover request containing CSG information from the MME as part of a forwarding relocation request, the AMF processes the request accordingly, as described in procedures 800 to 1200. For UE behavior: The UE provides the source and target cell's CAG or CSG information to the source radio access network (RAN) within the measurement report, as described in procedures 800 and 900, and the UE provides the source cell's CAG and CSG information to the source RAN within the measurement report, as described in procedures 1000 to 1200. For source RAN logic: The source RAN (e.g., source eNB or source gNB) uses logic to map cell IDs to corresponding CAG / CSG information, as described in procedure 1100. Furthermore, as described above, the process from 800 to 1200 does not require many changes to the call flow when switching from 4G EPS to 5G-NR, and vice versa.

[0137] Figure 13 A flowchart illustrating an example method 1300 implemented at a second core network according to some other embodiments of the present disclosure is shown. Reference will be made to this flowchart for discussion purposes. Figure 1 Method 1300 is described from the perspective of the second core network 150. Method 1300 can correspond to the second core network 150 (e.g., element 150-1) in... Figure 5 The process involves 500 operations.

[0138] like Figure 13 As shown, at block 1310, during the handover phase for a terminal device from a first cell in a first access network to a second cell in a second access network, the second core network 150 receives a first closed group identifier (ID) of the first cell from the first core network associated with the first access network. The first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other CSG or CAG. The first closed group ID is associated with either the CSG or CAG. At block 1320, the second core network 150 determines a second closed group ID associated with the other of the CSG ID or CAG ID based on the first closed group ID.

[0139] In some embodiments, the second core network performs access control for the device in the second cell based on the determined second closed group ID and subscription information. In some embodiments, the first closed group ID of the first cell is sent and received via the N26 interface through a forwarded relocation request message from the first core network to the second core network. In some embodiments, the second closed group ID is used by the second cell and is obtained by mapping the first closed group ID to the second closed group ID. In other words, determining the second closed group ID based on the first closed group ID includes mapping the first closed group ID to the second closed group ID. In some embodiments, the first closed group ID is mapped to the second closed group ID by the second core network based on at least one operator policy. In some embodiments, the second closed group ID is mapped to the first closed group ID by a network function. In other words, the mapping is performed by the network function.

[0140] In some embodiments, the first cell belongs to the CSG and the second cell belongs to the CAG, the first closed group ID of the first cell is the CSG ID of the first cell, and the second closed group ID is the CAG ID to be used by the second cell, and subscription information is obtained from the User Data Management (UDM); or the first cell belongs to the CAG and the second cell belongs to the CSG, the first closed group ID of the first cell is the CAG ID of the first cell, and the second closed group ID is the CSG ID to be used by the second cell, and subscription information is obtained from the Home Subscriber Server (HSS).

[0141] Figure 14 A flowchart illustrating an example method 1400 implemented at a first access network according to some other embodiments of the present disclosure is shown. Reference will be made to this flowchart for discussion purposes. Figure 1 Method 1400 is described from the perspective of the first access network 120. Method 1400 can correspond to the method described by the first access network in... Figure 6 The process involves 600 operations.

[0142] At box 1410, during a handover from a first cell of a first access network to a second cell of a second access network, the first access network 120 determines the closed group ID of the second cell based on the cell identifier (ID) of the second cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG. At box 1420, the first access network 120 sends the closed group ID of the second cell to the first core network.

[0143] In some embodiments, the closed group ID of the second cell is further sent to the second core network via a forwarding relocation request message. In some embodiments, the transmission of the closed group ID of the second cell is performed via a transmission configured such that the closed group ID of the second cell is further sent to the second core network via a forwarding relocation request message. In some embodiments, the closed group ID of the second cell is determined by mapping the cell ID of the second cell to the closed group ID of the second cell based on a configuration table. In some embodiments, determining the closed group ID of the second cell includes mapping the cell ID of the second cell to the closed group ID of the second cell based on a configuration table. In some embodiments, access control is performed by the second core network based on the closed group ID of the second cell and subscription information. In some embodiments, the transmission of the closed group ID of the second cell is performed via a transmission configured such that access control is performed by the second core network based on the closed group ID of the second cell and subscription information.

[0144] In some embodiments, the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is obtained from the User Data Management (UDM); or the first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is obtained from the Home Subscriber Server (HSS).

[0145] Figure 15 A flowchart illustrating an example method 1500 implemented at terminal device 110 according to some other embodiments of the present disclosure is shown. Reference will be made to this flowchart for discussion purposes. Figure 1 Method 1500 is described from the perspective of terminal device 110. Method 1500 can correspond to the method performed by the terminal device in... Figure 3A , Figure 3B and Figure 4 The operations performed at processes 300A, 300B, and 400.

[0146] like Figure 15 As shown, during the handover of the device from a first cell in a first access network to a second cell in a second access network, at box 1510, the terminal device obtains the closed group identifier (ID) of the second cell, where the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG. At box 1520, the terminal device sends a measurement report including the closed group ID of the second cell to the first access network.

[0147] In some embodiments, the closed group ID of the second cell is also sent from the first access network to the first core network via a handover request message. In some embodiments, the closed group ID of the second cell is also sent from the first core network to the second core network via a forwarding relocation request message. In some embodiments, the second core network performs access control for the second cell based on the closed group ID and subscription information of the second cell.

[0148] In some embodiments, the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is obtained from the User Data Management (UDM); or the first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is obtained from the Home Subscriber Server (HSS).

[0149] In some embodiments, the closed group ID of the second cell is the first closed group ID of the second cell, wherein the first closed group ID of the second cell is associated with one of CSG or CAG, and the first core network determines the second closed group ID of the second cell based on the first closed group ID of the second cell, wherein the second closed group ID of the second cell is associated with the other of CSG or CAG; and the first core network also performs access control based on the second closed group ID of the second cell and subscription information.

[0150] In some embodiments, the first closed group ID of the second cell is associated with the CAG, and the second closed group ID of the second cell is associated with the CSG, and the subscription information is CSG-related subscription information obtained from the Home Subscriber Server (HSS); or the first closed group ID of the second cell is associated with the CSG, and the second closed group ID of the second cell is associated with the CAG, and the subscription information is CAG-related subscription information obtained from the User Data Management (UDM).

[0151] In some embodiments, the first closed group ID of the second cell is the same as the second closed group ID of the first cell. In some embodiments, the first closed group ID of the second cell and the second closed group ID of the second cell are assigned from the same pool and follow the same semantics.

[0152] In some embodiments, the first core network performs access control for the second cell based on the closed group ID and subscription information of the second cell. In some embodiments, the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is CAG-related subscription information obtained from the combined User Data Management (UDM) and Home Subscriber Server (HSS); or the first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is CSG-related subscription information obtained from the combined UDM and HSS.

[0153] Figure 16 A flowchart illustrating an example method 1600 implemented at a second core network according to some other embodiments of the present disclosure is shown. Reference will be made to this flowchart for discussion purposes. Figure 1 Method 1600 is described from the perspective of the second core network 150. Method 1600 can correspond to the second core network 150 (e.g., element 150-1) in... Figure 7 The operations performed in process 700.

[0154] like Figure 16 As shown, during a handover of a device from a first cell in a first access network to a second cell in a second access network, at block 1610, the second core network receives the closed group identifier (ID) of the first cell from the first core network associated with the first access network, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other CSG or CAG. At block 1620, based on the received closed group ID of the first cell, the second core network obtains a list of allowed closed group IDs for the device associated with the other CSG or CAG from network functions. At block 1630, the second core network sends the list of allowed closed group IDs to the second access network.

[0155] In some embodiments, the closed group ID of the first cell is sent from the first core network to the second core network via a forwarding relocation request message, and is received by the second core network from the first core network. In some embodiments, the closed group ID of the first cell is a CSG ID, and the device's list of allowed closed group IDs is a list of allowed CAG IDs, and the second access network performs access control based on the list of allowed CAG IDs and the CAG ID of the second cell; or, the closed group ID of the first cell is a CAG ID, and the device's list of allowed closed group IDs is a list of allowed CSG IDs, and the second access network performs access control based on the list of allowed CSG IDs and the CSG ID of the second cell.

[0156] In some embodiments, an apparatus capable of performing method 1300 (e.g., second core network 150, such as element 150-1) may include components for performing the corresponding steps of method 1300. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module.

[0157] In some embodiments, the apparatus includes: components for receiving a first closed group identifier (ID) of a first cell from a first core network associated with the first access network during a handover of the device from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to one of a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), the second cell belongs to the other of a CSG or a CAG, and the first closed group ID is associated with one of a CSG or a CAG; and components for determining a second closed group ID associated with the other of a CSG ID or a CAG ID based on the first closed group ID.

[0158] In some embodiments, the second core network performs access control for the device in the second cell based on the determined second closed group ID and subscription information. In some embodiments, the first closed group ID of the first cell is sent via a forwarding relocation request message from the first core network to the second core network. In some embodiments, the second closed group ID will be used by the second cell and is obtained by mapping the first closed group ID to the second closed group ID.

[0159] In some embodiments, the first closed group ID is mapped to the second closed group ID by the second core network based on at least one operator policy. In some embodiments, the second closed group ID is mapped to the first closed group ID by network functions.

[0160] In some embodiments, the first cell belongs to the CSG and the second cell belongs to the CAG, the first closed group ID of the first cell is the CSG ID of the first cell, and the second closed group ID is the CAG ID to be used by the second cell, and subscription information is obtained from the User Data Management (UDM); or the first cell belongs to the CAG and the second cell belongs to the CSG, the first closed group ID of the first cell is the CAG ID of the first cell, and the second closed group ID is the CSG ID to be used by the second cell, and subscription information is obtained from the Home Subscriber Server (HSS).

[0161] In some embodiments, the device further includes components for performing additional steps in some embodiments of method 1300. In some embodiments, the components include at least one processor and at least one memory including computer program code configured to, together with the at least one processor, implement the performance of the device.

[0162] In some embodiments, an apparatus capable of performing method 1400 (e.g., a first access network 120) may include components for performing the corresponding steps of method 1400. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module.

[0163] In some embodiments, the apparatus includes: components for determining a closed group ID of a second cell based on a cell identifier (ID) of the second cell during a handover of the device from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to one of a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of a CSG or CAG; and components for transmitting the closed group ID of the second cell to a first core network.

[0164] In some embodiments, the enclosure group ID of the second cell is further sent to the second core network via a forwarded relocation request message. In some embodiments, the enclosure group ID of the second cell is determined by mapping the cell ID of the second cell to the enclosure group ID of the second cell based on a configuration table.

[0165] In some embodiments, access control is performed by a second core network based on the closed group ID and subscription information of the second cell. In some embodiments, the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is obtained from the User Data Management (UDM); or the first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is obtained from the Home Subscriber Server (HSS).

[0166] In some embodiments, the device further includes components for performing additional steps in some embodiments of method 1400. In some embodiments, the components include at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, implement the performance of the device.

[0167] In some embodiments, an apparatus capable of performing method 1500 (e.g., Figure 1 The terminal device may include components for performing the corresponding steps of method 1500. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module.

[0168] In some embodiments, the apparatus includes: components for acquiring a closed group identifier (ID) of a second cell during a handover of the device from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to one of a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of a CSG or CAG; and components for sending a measurement report including the closed group ID of the second cell to the first access network.

[0169] In some embodiments, the closed group ID of the second cell is also sent from the first access network to the first core network via a handover request message. In some embodiments, the closed group ID of the second cell is also sent from the first core network to the second core network via a forwarding relocation request message.

[0170] In some embodiments, the second core network performs access control for the second cell based on the closed group ID and subscription information of the second cell. In some embodiments, the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is obtained from the User Data Management (UDM); or the first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is obtained from the Home Subscriber Server (HSS).

[0171] In some embodiments, the closed group ID of the second cell is the first closed group ID of the second cell, wherein the first closed group ID of the second cell is associated with one of CSG or CAG, and the first core network determines the second closed group ID of the second cell based on the first closed group ID of the second cell, wherein the second closed group ID of the second cell is associated with the other of CSG or CAG; and the first core network also performs access control based on the second closed group ID of the second cell and subscription information.

[0172] In some embodiments, the first closed group ID of the second cell is associated with the CAG, and the second closed group ID of the second cell is associated with the CSG, and the subscription information is CSG-related subscription information obtained from the Home Subscriber Server (HSS); or the first closed group ID of the second cell is associated with the CSG, and the second closed group ID of the second cell is associated with the CAG, and the subscription information is CAG-related subscription information obtained from the User Data Management (UDM). In some embodiments, the first closed group ID of the second cell is the same as the second closed group ID of the first cell. In some embodiments, the first closed group ID and the second closed group ID of the second cell are assigned from the same pool and follow the same semantics.

[0173] In some embodiments, the first core network performs access control for the second cell based on the closed group ID and subscription information of the second cell. In some embodiments, the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is CAG-related subscription information obtained from the combined User Data Management (UDM) and Home Subscriber Server (HSS); or the first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is CSG-related subscription information obtained from the combined UDM and HSS.

[0174] In some embodiments, the device further includes components for performing additional steps in some embodiments of method 1500. In some embodiments, the components include at least one processor and at least one memory including computer program code configured to, together with the at least one processor, implement the performance of the device.

[0175] In some embodiments, an apparatus capable of performing method 1600 (e.g., second core network 150, particularly element 150-1) may include components for performing the corresponding steps of method 1600. These components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module.

[0176] In some embodiments, the apparatus includes: components for receiving a closed group identifier (ID) of a first cell from a first core network associated with the first access network during a handover of the device from a first cell of a first access network to a second cell of a second access network, wherein the first cell belongs to one of a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or CAG; components for obtaining a list of allowed closed group IDs of the device associated with the other of the CSG or CAG from network functions based on the received closed group ID of the first cell; and components for sending the list of allowed closed group IDs to the second access network.

[0177] In some embodiments, the closed group ID of the first cell is sent from the first core network to the second core network via a forwarding relocation request message. In some embodiments, the closed group ID of the first cell is a CSG ID, and the list of allowed closed group IDs of the device is a list of allowed CAG IDs obtained from the User Data Management (UDM), and the second core network or the second access network performs access control based on the list of allowed CAG IDs and the CAG ID of the second cell; or, the closed group ID of the first cell is a CAG ID, and the list of allowed closed group IDs of the device is a list of allowed CSG IDs obtained from the Home Subscriber Server (HSS), and the second core network or the second access network performs access control based on the list of allowed CSG IDs and the CSG ID of the second cell.

[0178] In some embodiments, the apparatus further includes components for performing additional steps in some embodiments of method 1600. In some embodiments, the components include at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, implement the performance of the apparatus.

[0179] Figure 17 This is a simplified block diagram of a device 1700 suitable for implementing embodiments of the present disclosure. The device 1700 can be provided to implement communication devices, such as terminal device 110, access networks 120, 130, and core network elements 140-1, 140-2, 150-1, and 150-2, as follows: Figure 1 As shown, device 1700 includes one or more processors 1710, one or more memories 1720 coupled to processor 1710, and one or more communication modules 1740 coupled to processor 1710.

[0180] The communication module 1740 is used for bidirectional communication. The communication module 1740 has at least one antenna to facilitate communication. The communication interface can represent any interface required for communication with other network devices.

[0181] Processor 1710 can be of any type suitable for a local technology network, and by way of non-limiting example, can include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), and processor based on a multi-core processor architecture. Device 1700 can have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0182] Memory 1720 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 1724, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disc (CD), digital video disk (DVD), and other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 1722 and other volatile memories that do not persist during power outages.

[0183] Computer program 1730 includes computer-executable instructions that are executed by the associated processor 1710. Program 1730 may be stored in ROM 1724. Processor 1710 may perform any suitable actions and processes by loading program 1730 into RAM 1722.

[0184] The embodiments of this disclosure can be implemented by a program, such that device 1700 can execute the functions shown in Figures 3 to 4. Figure 16 Any process discussed in this disclosure. Embodiments of this disclosure may also be implemented by hardware or by a combination of software and hardware.

[0185] In some embodiments, program 1730 may be tangibly contained in a computer-readable medium, which may be included in device 1700 (such as memory 1720) or other storage device accessible to device 1700. Device 1700 may load program 1730 from the computer-readable medium into RAM 1722 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc.

[0186] Figure 18 An example of a computer-readable medium 1800 in the form of a CD or DVD according to some embodiments of the present disclosure is illustrated. A program 1730 is stored on the computer-readable medium. It should be noted that although the computer-readable medium 1800 is depicted in the form of a CD or DVD, the computer-readable medium 1800 may be any other form suitable for carrying or storing the program 1730.

[0187] Generally, the various embodiments of this disclosure can be implemented using hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented using hardware, while others can be implemented using firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented using hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0188] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in a program module, which execute in a device on a target real or virtual processor to perform the above-mentioned... Figures 6 to 7 The method described is 600 or 700. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. In various embodiments, the functionality of a program module can be combined or split among program modules as needed. The machine-executable instructions of a program module can be executed on a local or distributed device. In a distributed device, a program module can reside on both local and remote storage media.

[0189] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0190] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0191] Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination of the foregoing. More specific examples of computer-readable storage media will include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. The term "non-transient" as used herein is a limitation on the medium itself (i.e., tangible, not signaling), not a limitation on the persistence of data storage (e.g., RAM and ROM).

[0192] Furthermore, although operations are described in a specific order, this should not be construed as requiring the operations to be performed in the specific order shown or sequentially, or to perform all of the shown operations to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, various features that may be described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0193] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above may be disclosed as exemplary forms of implementing the claims.

Claims

1. A second core network, 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 second core network to at least execute: During the handover of the device from a first cell of a first access network to a second cell of a second access network, the device receives a first closed group identifier (ID) of the first cell from a first core network associated with the first access network, wherein the first cell belongs to one of a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), the second cell belongs to the other of the CSG or the CAG, and the first closed group ID is associated with the CSG or the CAG. as well as Based on the first closed group ID, determine a second closed group ID associated with the other item in the CSG ID or the CAG ID.

2. The second core network according to claim 1, wherein the instructions, when executed by the at least one processor, further cause the second core network to perform at least: Based on the determined second closed group ID and subscription information, access control is performed on the device in the second cell.

3. The second core network according to claim 1, wherein the first closed group ID of the first cell is received via a forwarding relocation request message from the first core network to the second core network.

4. The second core network according to claim 1, wherein the second closed group ID will be used by the second cell, and the determination includes mapping the first closed group ID to the second closed group ID.

5. The second core network according to claim 4, wherein the mapping is based on at least one operator policy.

6. The second core network according to claim 4, wherein the mapping is performed by network functions.

7. The second core network according to claim 2, wherein: The first cell belongs to the CSG, the second cell belongs to the CAG, the first closed group ID of the first cell is the CSG ID of the first cell, and the second closed group ID is the CAG ID to be used by the second cell, and the subscription information is obtained from User Data Management (UDM); or The first cell belongs to the CAG, the second cell belongs to the CSG, the first closed group ID of the first cell is the CAG ID of the first cell, and the second closed group ID is the CSG ID to be used by the second cell, and the subscription information is obtained from the Home Subscriber Server (HSS).

8. A first access network, 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 first access network to perform at least the following: During the handover of the device from a first cell in the first access network to a second cell in the second access network, the closed group ID of the second cell is determined based on the cell identifier (ID) of the second cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or the CAG; and Send the closed group ID of the second cell to the first core network.

9. The first access network according to claim 8, wherein the transmission of the closed group ID of the second cell is performed via a transmission configured such that the closed group ID of the second cell is further transmitted to the second core network via a forwarding relocation request message.

10. The first access network according to claim 7, wherein determining the closed group ID of the second cell includes: Based on the configuration table, the cell ID of the second cell is mapped to the closed group ID of the second cell.

11. The first access network of claim 8, wherein the transmission of the closed group ID of the second cell is performed via a transmission configured such that access control is performed by the second core network based on the closed group ID and subscription information of the second cell.

12. The first access network of claim 11, wherein the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is obtained from User Data Management (UDM); or The first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information will be obtained from the Home Subscriber Server (HSS).

13. A method comprising: During the handover of the device from a first cell in a first access network to a second cell in a second access network, the device obtains the Closed Group Identifier (ID) of the second cell, wherein the first cell belongs to either a Closed Subscriber Group (CSG) or a Closed Access Group (CAG), and the second cell belongs to the other of the CSG or the CAG; and The device sends a measurement report, including the closed group ID of the second cell, to the first access network.

14. The method of claim 13, further comprising: The closed group ID of the second cell is sent from the first access network to the first core network via a handover request message.

15. The method of claim 14, further comprising: The closed group ID of the second cell is sent from the first core network to the second core network via a forwarded relocation request message.

16. The method of claim 15, further comprising: The second core network performs access control for the second cell based on the closed group ID and subscription information of the second cell.

17. The method of claim 16, wherein The first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is obtained from User Data Management (UDM); or The first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is obtained from the Home Subscriber Server (HSS).

18. The method of claim 14, wherein the enclosure group ID of the second cell is a first enclosure group ID of the second cell, wherein the first enclosure group ID of the second cell is associated with one of the CSG or the CAG, and wherein the method further comprises: The second closed group ID of the second cell is determined by the first core network based on the first closed group ID of the second cell, wherein the second closed group ID of the second cell is associated with another of the CSG or the CAG; as well as The first core network performs access control based on the second closed group ID and subscription information of the second cell.

19. The method of claim 18, wherein: The first closed group ID of the second cell is associated with the CAG, and the second closed group ID of the second cell is associated with the CSG, and the subscription information is CSG-related subscription information and is obtained from the Home Subscriber Server (HSS), or The first closed group ID of the second cell is associated with the CSG, and the second closed group ID of the second cell is associated with the CAG, and the subscription information is CAG-related subscription information and is obtained from User Data Management (UDM).

20. The method of claim 19, wherein the first closed group ID of the second cell is the same as the second closed group ID of the first cell.

21. The method of claim 19, wherein the first closed group ID of the second cell and the second closed group ID of the second cell are assigned from the same pool and follow the same semantics.

22. The method of claim 13, further comprising: The first core network performs access control for the second cell based on the closed group ID and subscription information of the second cell.

23. The method of claim 22, wherein the first cell belongs to the CSG, the second cell belongs to the CAG, the closed group ID of the second cell is the CAG ID of the second cell, and the subscription information is CAG-related subscription information obtained from the combined User Data Management (UDM) and Home Subscriber Server (HSS); or The first cell belongs to the CAG, the second cell belongs to the CSG, the closed group ID of the second cell is the CSG ID of the second cell, and the subscription information is CSG-related subscription information obtained from the combined UDM and HSS.

24. A second core network, 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 second core network to at least execute: During the handover of the device from a first cell of a first access network to a second cell of a second access network, the device receives the closed group identifier (ID) of the first cell from a first core network associated with the first access network, wherein the first cell belongs to either a closed subscriber group (CSG) or a closed access group (CAG), and the second cell belongs to the other of the CSG or the CAG. Based on the closed group ID received from the first cell, obtain one or more allowed closed group IDs associated with the device and the other of the CSG or CAG from the network functions; as well as Send one or more Allow Closed Group IDs to the second access network.

25. The second core network of claim 24, wherein the closed group ID of the first cell is received via a forwarding relocation request message from the first core network to the second core network.

26. The second core network of claim 24, wherein the instructions, when executed by the at least one processor, cause the second core network to perform at least: Access control is performed based on the one or more permitted closed group IDs and the closed group ID of the first cell; and wherein: The closed group ID of the first cell is a CSG ID, and the one or more allowed closed group IDs of the device are one or more allowed CAG IDs obtained from User Data Management (UDM). The second core network or the second access network performs access control based on the one or more allowed CAG IDs and the CAG ID of the second cell; or The closed group ID of the first cell is a CAG ID, and the one or more allowed closed group IDs of the device are one or more allowed CSG IDs obtained from the Home Subscriber Server (HSS). The second core network or the second access network performs access control based on the list of allowed CSG IDs and the CSG ID of the second cell.

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