Method and apparatus for accessing core network via gateway function

Abstract

Techniques for accessing a core network via an access point and a gateway function are provided. For example, a method includes determining one or more candidate gateway functions for accessing a core network via an access point; sending a request for accessing a core network using the one or more gateway functions to the one or more candidate gateway functions or core network functions; and receiving, for each candidate gateway function, a request response from the gateway function or the core network function, the request response configured to indicate whether access to the core network via the respective gateway function is rejected, and in the case of rejection, indicate a rejection cause. The method may be performed by a terminal device (e.g., a user equipment (UE)). A corresponding method that may be performed by a network device is also provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Indian Provisional Patent Application No. 202211045684 filed on August 10, 2022, the contents of which are incorporated herein by reference as if reproduced in their entirety. Technical Field

[0003] The subject disclosure generally relates to wireless communication systems, and more particularly to accessing a core network of a wireless communication system. More particularly, the subject disclosure provides methods and apparatus for accessing a core network via an access point and a gateway function. Background Art

[0004] Wireless communication systems are constantly evolving. There is a constant demand for higher data rates and higher quality of service. Reliability requirements are increasing, and methods and means are being developed to ensure reliable connections and data services while minimizing transmission delays.

[0005] Developing networks can provide new services to customers. One service is network slicing, which provides connectivity, quality of service, and data processing solutions tailored to specific customer needs. A network slice is a logical end-to-end virtual network that can be created dynamically and provides specific capabilities and features. Multiple network slices can be created on top of a common shared physical network infrastructure to run services that may have different requirements for latency, reliability, throughput, and mobility.

[0006] In addition, various options have been developed for accessing the telecommunication system via different access points that differ in supporting different slices. Depending on the slice required by the terminal device, a suitable access gateway should be selected. Using an access gateway requires determining whether a specific access gateway meets the slice requirements of the terminal device.

[0007] Therefore, there is a need to exchange information about the slicing requirements of various access gateways. Summary of the invention

[0008] According to a first aspect of the subject disclosure, a method for operating a terminal device in a communication network is provided. The communication network includes a core network and an access point. The method includes determining one or more candidate gateway functions for accessing the core network via the access point. The method also includes sending a request to one or more candidate gateway functions or core network functions for accessing the core network using one or more gateway functions. The method also includes receiving a request response from the gateway function or the core network function for each candidate gateway function, the request response being configured to indicate whether access to the core network via the corresponding gateway function is denied, and in the case of denial, indicating the denial reason.

[0009] In some embodiments, the rejection reason includes the gateway function not supporting one or more slices.

[0010] In some embodiments, the core network is a 3GPP core network, the access point is a non-3GPP access point, and the gateway function is for at least one of a trusted non-3GPP access and an untrusted non-3GPP access.

[0011] In some embodiments, the gateway function includes at least one of a Non-3GPP Interworking Function (N3IWF) and a Trusted Non-3GPP Gateway Function (TNGF).

[0012] In some embodiments, the method further comprises determining a set of one or more slices for use by the terminal device, wherein the request is configured to indicate the set of one or more slices.

[0013] In some embodiments, each slice of the one or more slices is identified by corresponding single network slice selection assistance information (S-NSSAI).

[0014] In some embodiments, the request response is configured to indicate a subset of slices of the determined set, wherein for the indicated subset, access via the corresponding gateway function is denied (or allowed).

[0015] In some embodiments, a plurality of candidate gateway functions are determined, and sending of the request to a second one of the candidate gateway functions is performed prior to receiving a request response from a first one of the candidate gateway functions.

[0016] In some embodiments, a plurality of candidate gateway functions are determined, and wherein sending the request to a second one of the candidate gateway functions is performed after receiving a request response from a first one of the candidate gateway functions.

[0017] In some embodiments, the request comprises a registration or authentication request and / or the request response comprises a registration or authentication response.

[0018] In this case, the method may further include selecting a candidate gateway function from the determined one or more gateway functions; and sending a registration or authentication request to the core network function via the selected gateway function.

[0019] In some embodiments, the core network functions include an access and mobility management function (AMF).

[0020] According to a second aspect of the subject disclosure, a method for operating a network device in a communication network is provided. The communication network includes a core network and an access point. The method includes receiving a request for a terminal device to use a gateway function when accessing the core network via the access point. The method also includes sending a request response, the request response being configured to indicate whether access of the terminal device to the core network via the gateway function is denied, and in the case of denial, indicating a denial reason.

[0021] In some embodiments, the rejection reason includes the gateway function not supporting one or more slices.

[0022] In some embodiments, the core network is a 3GPP core network, the access point is a non-3GPP access point, and the gateway function is for at least one of a trusted non-3GPP access and an untrusted non-3GPP access.

[0023] In some embodiments, the gateway function includes at least one of a Non-3GPP Interworking Function (N3IWF) and a Trusted Non-3GPP Gateway Function (TNGF).

[0024] In some embodiments, the request is configured to indicate a set of one or more slices for use by the terminal device.

[0025] In some embodiments, each slice of the one or more slices is identified by corresponding single network slice selection assistance information (S-NSSAI).

[0026] In some embodiments, the method further comprises determining a subset of slices of the indicated set, and the request response is configured to indicate the determined subset, wherein access via the gateway function is denied (or allowed) for the indicated subset.

[0027] In some embodiments, the network device includes a core network function, wherein the network device receives the request via a gateway function. Determining the subset may include obtaining gateway slice information for the requested gateway function; retrieving terminal slice information from the received request based on the indicated set of one or more slices; and determining the subset of allowed slices based on an overlap between the gateway slice information and the terminal slice information.

[0028] In some embodiments, the method further comprises, in response to determining that the overlap is a true subset of the indicated set, identifying an alternative gateway function based on the terminal slice information. In this case, the request response may be configured to indicate the alternative gateway function.

[0029] In some embodiments, the network device includes gateway functionality.

[0030] In some embodiments, the method further includes sending an authentication request for authentication of the terminal device to an access and mobility management function (AMF); receiving an authentication response indicating a rejection reason from the AMF; and including the rejection reason in a request response to the terminal device.

[0031] In some embodiments, the network device includes core network functionality.

[0032] In some embodiments, the request comprises a registration or authentication request and / or the request response comprises a registration or authentication response.

[0033] In some embodiments, the core network functions include an access and mobility management function (AMF).

[0034] According to a third aspect of the subject disclosure, there is provided a terminal device for use in a communication network comprising a core network and an access point. The terminal device comprises at least one processor; and at least one memory comprising computer program code. When executed by at least one process, the computer program code causes the terminal device to perform at least the steps of the method according to the first aspect.

[0035] Specifically, it causes the terminal device to determine one or more candidate gateway functions for accessing the core network via the access point; send a request for accessing the core network using one or more gateway functions to one or more candidate gateway functions or core network functions; and receive a request response from the gateway function or core network function for each candidate gateway function, the request response being configured to indicate whether access to the core network via the corresponding gateway function is denied, and in the case of denial, indicate the reason for denial.

[0036] In some embodiments, the rejection reason includes the gateway function not supporting one or more slices.

[0037] In some embodiments, the core network is a 3GPP core network, the access point is a non-3GPP access point, and the gateway function is for at least one of a trusted non-3GPP access and an untrusted non-3GPP access.

[0038] In some embodiments, the gateway function includes at least one of a Non-3GPP Interworking Function (N3IWF) and a Trusted Non-3GPP Gateway Function (TNGF).

[0039] In some embodiments, the computer program code causes the terminal device to further determine a set of one or more slices for use by the terminal device, wherein the request is configured to indicate the set of one or more slices.

[0040] In some embodiments, each slice of the one or more slices is identified by corresponding single network slice selection assistance information (S-NSSAI).

[0041] In some embodiments, the request response is configured to indicate a subset of slices of the determined set, wherein for the indicated subset, access via the corresponding gateway function is denied (or allowed).

[0042] In some embodiments, a plurality of candidate gateway functions are determined, and wherein sending the request to a second one of the candidate gateway functions is performed before or after receiving a request response from a first one of the candidate gateway functions.

[0043] In some embodiments, the request comprises a registration or authentication request and / or the request response comprises a registration or authentication response.

[0044] In some embodiments, the computer program code causes the terminal device to further select a candidate gateway function from the determined one or more gateway functions; and send a registration or authentication request to the core network function via the selected gateway function.

[0045] In some embodiments, the core network functions include an access and mobility management function (AMF).

[0046] According to a fourth aspect of the subject disclosure, there is provided a network device for use in a communication network comprising a core network and an access point. The network device comprises at least one processor; and at least one memory comprising computer program code. When executed by the at least one processor, the computer program code causes the network device to perform at least the steps of the method according to the second aspect.

[0047] Specifically, it causes the network device to receive a request for a terminal device to use a gateway function when accessing a core network via an access point; and to send a request response to the terminal device, wherein the request response is configured to indicate whether the terminal device's access to the core network via the gateway function is denied, and if denied, to indicate the reason for the denial.

[0048] In some embodiments, the rejection reason includes the gateway function not supporting one or more slices.

[0049] In some embodiments, the core network is a 3GPP core network, the access point is a non-3GPP access point, and the gateway function is for at least one of a trusted non-3GPP access and an untrusted non-3GPP access.

[0050] In some embodiments, the gateway function includes at least one of a Non-3GPP Interworking Function (N3IWF) and a Trusted Non-3GPP Gateway Function (TNGF).

[0051] In some embodiments, the request is configured to indicate a set of one or more slices for use by the terminal device.

[0052] In some embodiments, each slice of the one or more slices is identified by corresponding single network slice selection assistance information (S-NSSAI).

[0053] In some embodiments, the computer program code causes the network device to further determine a subset of slices of the indicated set, wherein the request response is configured to indicate the determined subset, wherein access via the gateway function is denied (or allowed) for the indicated subset.

[0054] In some embodiments, the network device includes a core network function, wherein the network device receives the request via a gateway function. Determining the subset includes obtaining gateway slice information for the requested gateway function; retrieving terminal slice information from the received request based on the indicated set of one or more slices; and determining the subset of slices based on an overlap between the gateway slice information and the terminal slice information.

[0055] In some embodiments, the computer program code causes the network device to further identify an alternate gateway function based on the terminal slice information in response to determining that the overlap is a true subset of the indicated set, wherein the request response is configured to indicate the alternate gateway function.

[0056] In some embodiments, the network device includes gateway functionality.

[0057] In some embodiments, the computer program code causes the network device to further send an authentication request for authentication of the terminal device to an access and mobility management function (AMF); receive an authentication response indicating a rejection reason from the AMF; and include the rejection reason in a request response to the terminal device.

[0058] In some embodiments, the network device includes core network functionality.

[0059] In some embodiments, the request comprises a registration or authentication request and / or the request response comprises a registration or authentication response.

[0060] In some embodiments, the core network functions include an access and mobility management function (AMF).

[0061] In a first aspect, a non-transitory computer readable medium is provided, the medium containing computer executable instructions, which when executed on one or more processors perform the steps of the method according to the first aspect or the second aspect.

[0062] Depending on the desired configuration, the above aspects and features can be implemented in systems, apparatuses, methods, articles, and / or non-transitory computer-readable media. The subject disclosure can be implemented in and / or used with many different types of devices, including but not limited to any of mobile phones, tablet computers, wearable computing devices, portable media players, and various other computing devices.

[0063] The subject disclosure is intended to provide a brief overview of some aspects and features disclosed in accordance with the subject disclosure. Therefore, it should be understood that the above-mentioned features are merely examples and should not be interpreted as narrowing the scope of the subject disclosure in any way. Other features, aspects and advantages of the subject disclosure will become clear through the following detailed description, drawings and claims.

[0064] List of abbreviations

[0065] In the subject matter of the present disclosure, the following abbreviations are used and should be understood in accordance with the given definitions:

[0066] 3GPP: Third Generation Partnership Project

[0067] 5G: Fifth generation (mobile communication network)

[0068] 5GC: 5G Core

[0069] 5GS: 5G System

[0070] AF: Application Function

[0071] AMF: Access and Mobility Management Function

[0072] AN: Access Network

[0073] APN: Access Point Name

[0074] AUSF: Authentication Server Function

[0075] BS: Base Station

[0076] CDMA: Code Division Multiple Access

[0077] CN: Core Network

[0078] CP: Control Plane

[0079] eNB: Evolved Node B

[0080] EAP: Extensible Authentication Protocol

[0081] EPC: Evolved Packet Core

[0082] ePCO: Extended PCO

[0083] EPS: Evolved Packet System

[0084] ETSI: European Telecommunications Standards Institute

[0085] E-UTRAN: Evolved UMTS Terrestrial Radio Access

[0086] FQDN: Fully Qualified Domain Name

[0087] IE: Information Element

[0088] IKE: Internet Key Exchange

[0089] IP: Internet Protocol

[0090] IPSec: IP Security

[0091] LTE: Long Term Evolution

[0092] MME: Mobility Management Entity

[0093] N3IWF: Non-3GPP Interworking Function

[0094] NAS: Non-Access Stratum

[0095] NR: New Radio

[0096] NSSAI: Network Slice Selection Assistance Information

[0097] NSSF: Network Slice Selection Function

[0098] PCF: Policy Control Function

[0099] PCO: Protocol Configuration Options

[0100] PDN: Packet Data Network

[0101] PDP: Packet Data Protocol

[0102] PGW: PDN Gateway

[0103] PGW-C: PGW control function

[0104] PLMN: Public Land Mobile Network

[0105] RAN: Radio Access Network

[0106] RCS: Rich Communication Services

[0107] RRC: Radio Resource Control (protocol)

[0108] RSD: Routing Descriptor

[0109] SGW: Serving Gateway

[0110] SIM: Subscriber Identity Module

[0111] SMF: Session Management Function

[0112] S-NSSAI: Single NSSAI

[0113] TNGF: Trusted Non-3GPP Gateway Function

[0114] TS: Technical Specification

[0115] UDM: Unified Data Management

[0116] UE: User Equipment

[0117] UPF: User Plane Function

[0118] URLLC: Ultra-Reliable Low-Latency Communications

[0119] URSP: UE Routing Selection Policy

[0120] VoNR: Voice over NR BRIEF DESCRIPTION OF THE DRAWINGS

[0121] The subject matter of the subject disclosure may be better understood when the following detailed description of various embodiments is considered in conjunction with the following drawings, in which:

[0122] Figure 1 A schematic diagram of an example communication system including a base station and a plurality of communication devices is shown;

[0123] Figure 2 A schematic diagram of an example mobile communication device is shown;

[0124] Figure 3 A schematic diagram of an example control device is shown;

[0125] Figure 4 A schematic diagram showing another example communication system having an access point, a gateway function, and a core network function;

[0126] Figure 5 A diagram showing a communication flow between a terminal device and a network device according to one embodiment;

[0127] Figure 6 A diagram showing the communication flow between elements according to another embodiment;

[0128] Figure 7 A flow chart of a method according to one aspect is shown;

[0129] Figure 8 A flow chart showing a method according to another aspect; and

[0130] Fig. 9A diagram showing a communication flow between a terminal device and a network device according to another embodiment. DETAILED DESCRIPTION

[0131] Before explaining the examples in detail, refer to Figures 1 to 3 Certain general principles of wireless communication systems and mobile communication devices are briefly explained to aid understanding of the technology behind the described examples.

[0132] In such Figure 1 In the wireless communication system 100 shown, wireless access is provided to mobile communication devices or terminal devices (e.g., user equipment UE) 102, 104, 105 via at least one base station (e.g., next generation NB, gNB) or similar wireless transmission and / or receiving node (such as access point). The base station can be controlled or assisted by at least one appropriate controller device so as to be able to operate the base station and manage mobile communication devices communicating with the base station. The controller device can be located in a radio access network (e.g., wireless communication system 100) or a core network (CN) (not shown) and can be implemented as a central device, or its functions can be distributed over several devices. The controller device can be part of the base station and / or provided by a separate entity such as a radio network controller. Figure 1 In the embodiment, control means 108 and 109 are shown to control the respective macro base stations 106 and 107. The control means of the base stations may be interconnected with other control entities. The control means are typically provided with storage capacity and at least one data processor. The control means and functions may be distributed among a plurality of control units. In some systems, the control means may be provided additionally or alternatively in a radio network controller.

[0133] exist Figure 1 In FIG. 1 , base stations 106 and 107 are shown connected to a wider communications network 113 via a gateway 112. A further gateway function may be provided to connect to another network.

[0134] As used herein, the term "base station" has the full meaning of its ordinary meaning and includes at least a wireless communication station installed in a fixed location and used to communicate as part of a wireless telephone system or radio system. The communication area (or coverage area) of a base station may be referred to as a "cell". A base station and UEs may be configured to communicate over a transmission medium using any of a variety of radio access technologies (RATs) (also referred to as wireless communication technologies) or telecommunication standards described below. Figure 1 As shown, while one of the base stations may act as a "serving cell" for the UE, each UE may also be able to receive signals from (and possibly within communication range of) one or more other cells (which may be provided by the base station and / or any other base station), which may be referred to as "neighboring cells."

[0135] Smaller base stations 116, 118, and 120 may also be connected to the network 113, for example, via a separate gateway function and / or via a controller of a macro-level station. Base stations 116, 118, and 120 may be micro or femto-level base stations, etc. In this example, stations 116 and 118 are connected via gateway 111, and station 120 is connected via controller device 108. In some embodiments, smaller stations may not be provided. Smaller base stations 116, 118, and 120 may be part of a second network (e.g., WLAN) and may be WLAN APs. Communication devices 102, 104, and 105 may access the communication system based on various access technologies, such as code division multiple access (CDMA) or wideband CDMA (WCDMA). Other non-limiting examples include time division multiple access (TDMA), frequency division multiple access (FDMA), and various schemes thereof, such as interleaved frequency division multiple access (IFDMA), single carrier frequency division multiple access (SC-FDMA), and orthogonal frequency division multiple access (OFDMA), space division multiple access (SDMA), etc.

[0136] An example of a wireless communication system is an architecture standardized by the Third Generation Partnership Project (3GPP). The latest 3GPP-based development is generally referred to as the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology. The various development stages of the 3GPP specification are called releases. The latest development of LTE is generally referred to as Advanced LTE (LTE-A). LTE (LTE-A) adopts a wireless mobile architecture called Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a core network called Evolved Packet Core (EPC). The base station of such a system is called an evolved or enhanced Node B (eNB) and provides E-UTRAN features to communication devices, such as user plane packet data convergence / radio link control / media access control / physical layer protocol (PDCP / RLC / MAC / PHY) and control plane radio resource control (RRC) protocol terminals. Other examples of radio access systems include those provided by base stations of systems based on technologies such as wireless local area networks (WLAN) and / or WiMax (Worldwide Interoperability for Microwave Access). The base station can provide coverage for an entire cell or similar radio service area. The core network elements include the Mobility Management Entity (MME), the Serving Gateway (S-GW) and the Packet Gateway (P-GW).

[0137] An example of a suitable communication system is the 5G or NR concept. The network architecture in NR can be similar to that of Advanced LTE. The base stations of the NR system can be called next generation Node B (gNB). Changes in the network architecture can depend on the need to support various radio technologies and more refined QoS support, as well as some on-demand requirements, such as QoS levels for supporting user point of view QoE. In addition, network-aware services and applications, as well as service and application-aware networks, can bring changes to the architecture. These are related to information-centric network (ICN) and user-centric content delivery network (UC-CDN) approaches. NR can use multiple-input multiple-output (MIMO) antennas, more base stations or nodes than LTE (the so-called small cell concept), including macro sites that operate in cooperation with smaller base stations, and may also adopt various radio technologies to obtain better coverage and enhanced data rates.

[0138] Future networks may utilize network function virtualization (NFV), which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that can be operationally connected or linked together to provide services. A virtualized network function (VNF) may include one or more virtual machines that run computer program code using standard or generic types of servers rather than custom hardware. Cloud computing or data storage may also be utilized. In radio communications, this may mean that node operations are performed at least in part in a server, host, or node that is operably coupled to a remote radio head. Node operations may also be distributed among multiple servers, nodes, or hosts. It should also be understood that the distribution of work between core network operations and base station operations may be different from LTE, or even non-existent.

[0139] An example 5G core network (CN) includes functional entities. The CN is connected to the UE via the radio access network (RAN). The UPF (User Plane Function) whose role is called PSA (PDU Session Anchor) can be responsible for forwarding frames back and forth between the DN (data network) and the tunnels established over 5G towards (multiple) UEs to exchange services with the DN.

[0140] The UPF is controlled by the SMF (Session Management Function), which receives policies from the PCF (Policy Control Function). The CN may also include an AMF (Access and Mobility Function or Access and Mobility Management Function).

[0141] Now refer to Figure 2 describing in more detail possible mobile communication devices, Figure 2A schematic partial cross-sectional view of a communication device 200 is shown. Such a communication device is generally referred to as a user equipment (UE) or terminal device. Suitable mobile communication devices can be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or mobile device, such as a mobile phone or a so-called "smart phone", a computer equipped with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal data assistant (PDA) or a tablet computer equipped with a wireless communication function, or any combination of these devices, etc. For example, a mobile communication device can provide communications for carrying data such as voice, e-mail (email), text messages, multimedia, etc. Therefore, users can be supplied and provided with a variety of services via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communications or multimedia services, or simply access to a data communication network system (such as the Internet). Broadcast or multicast data can also be provided to users. Non-limiting examples of content include downloads, television and radio programs, videos, advertisements, various alarms and other information.

[0142] In industrial applications, the communications device may be a modem integrated into an industrial actuator (e.g., a robotic arm) and / or a modem acting as an Ethernet hub, which would act as a connection point for one or more connected Ethernet devices (the connection may be wired or wireless).

[0143] The mobile device is typically equipped with at least one data processing entity 201, at least one memory 202, and other possible components 203 used in the software and hardware-assisted execution of the tasks it is designed to perform, including controlling access to and communication with access systems and other communication devices. The data processing, storage and other related control means may be provided on an appropriate circuit board and / or in a chipset. This feature is represented by reference numeral 204. The user can control the operation of the mobile device by means of a suitable user interface, such as a keypad 205, voice commands, a touch-sensitive screen or touchpad, a combination thereof, etc. A display 208, a speaker and a microphone may also be provided. In addition, the mobile communication device may include appropriate connectors (wired or wireless) to other devices and / or for connecting external accessories (e.g., a hands-free device).

[0144] The communication device 200 may receive signals over the air or radio interface 207 via suitable means for receiving, and may transmit signals via suitable means for transmitting radio signals. Figure 2 In the mobile device, the transceiver arrangement is schematically represented by block 206. The transceiver arrangement 206 may be provided, for example, by means of a radio component and an associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0145] If desired, the communication device 200 may additionally or alternatively be configured to communicate using one or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one or more mobile television broadcast standards (e.g., ATSC-M / H or DVB-H), and / or any other wireless communication protocol. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0146] generally, Figure 2 The communication device 200 shown includes a collection of components configured to perform core functions. For example, the collection of components can be implemented as a system on a chip (SOC), which can include parts for various purposes. Alternatively, the collection of components can be implemented as separate components or groups of components for various purposes. The collection of components can be (e.g., communicatively; directly or indirectly) coupled to various other circuits of the communication device 200.

[0147] The communication device 200 may include at least one antenna for communicating with a transmitter and a receiver (e.g., a transceiver device 206). Alternatively, the transmitting antenna and the receiving antenna may be separate. The communication device 200 may also include a processor (e.g., at least one data processing entity 201), which is configured to provide signals to the transmitter and the receiver and receive signals from the transmitter and the receiver, respectively, and control the functions of the communication device 200. The processor may be configured to control the functions of the transmitter and the receiver by implementing control signaling to the transmitter and the receiver via electrical conductors. Similarly, the processor may be configured to control other elements of the communication device 200 by implementing control signaling via electrical conductors, which connect the processor to other elements, such as a display (e.g., a display 208) or a memory (e.g., at least one memory 202). For example, a processor may be embodied in various ways, including circuitry, at least one processing core, one or more microprocessors with accompanying digital signal processor(s), one or more processors without accompanying digital signal processor(s), one or more coprocessors, one or more multi-core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits (e.g., application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), etc.), or some combination thereof. Thus, in some examples, a processor may include multiple processors or processing cores.

[0148] The communication device 200 may be capable of operating using one or more air interface standards, communication protocols, modulation types, access types, etc. The signals sent and received by the processor may include signaling information in accordance with the air interface standard of the applicable cellular system and / or any number of different wired or wireless network technologies, including but not limited to Wi-Fi, wireless local area network (WLAN) technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, 802.16, 802.3, ADSL, DOCSIS, etc. In addition, these signals may include voice data, user generated data, user requested data, etc.

[0149] For example, the communication device 200 and / or the cellular modem therein may be capable of operating according to various first generation (1G) communication protocols, second generation (2G or 2.5G) communication protocols, third generation (3G) communication protocols, fourth generation (4G) communication protocols, fifth generation (5G) communication protocols, Internet Protocol Multimedia Subsystem (IMS) communication protocols (e.g., Session Initiation Protocol (SIP)), etc. For example, the communication device 200 may be capable of operating according to 2G wireless communication protocols IS-136, Time Division Multiple Access TDMA, Global System for Mobile Communications GSM, IS-95, Code Division Multiple Access CDMA, etc. In addition, for example, the communication device 200 may be capable of operating according to 2.5G wireless communication protocols General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), etc. In addition, for example, the communication device 200 may be capable of operating according to 3G wireless communication protocols, such as Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access 2000 (CDMA2000), Wideband Code Division Multiple Access (WCDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), etc. The communication device 200 may also be capable of operating according to 3.9G wireless communication protocols, such as Long Term Evolution (LTE), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), etc. In addition, for example, the communication device 200 may be capable of operating according to 4G wireless communication protocols (such as LTE-Advanced, 5G, etc.) and similar wireless communication protocols that may be developed subsequently.

[0150] It should be understood that the processor may include a circuit system for implementing the audio / video and logic functions of the communication device 200. For example, the processor may include a digital signal processor device, a microprocessor device, an analog-to-digital converter, a digital-to-analog converter, etc. The control and signal processing functions of the communication device 200 may be allocated between these devices according to their respective capabilities. The processor may also include an internal voice encoder (VC), an internal data modem (DM), etc. In addition, the processor may include functions for operating one or more software programs, which may be stored in a memory. Typically, the processor and the stored software instructions may be configured to cause the communication device 200 to perform an action. For example, the processor may be able to operate a connection program, such as a web browser. The connection program may allow the communication device 200 to send and receive network content, such as location-based content, according to a protocol (such as a wireless application protocol (WAP), a hypertext transfer protocol (HTTP), etc.).

[0151] The communication device 200 may also include a user interface that may be operably coupled to the processor, including, for example, headphones or speakers, ringers, microphones, displays, user input interfaces, and the like. As described above, the display may include a touch-sensitive display, where a user may touch and / or make gestures to make selections, input values, and the like. The processor may also include a user interface circuit system that is configured to control at least some functions of one or more elements of the user interface, such as speakers, ringers, microphones, displays, and the like. The processor and / or the user interface circuit system including the processor may be configured to control one or more functions of one or more elements of the user interface by computer program instructions (e.g., software and / or firmware) stored on a memory accessible to the processor (e.g., volatile memory, non-volatile memory, and the like). The communication device 200 may include a battery for powering various circuits associated with the mobile terminal, for example, a circuit for providing mechanical vibration as a detectable output. The user input interface may include a device that allows the communication device 200 to receive data, such as a keypad (e.g., keypad 206) and / or other input devices. The keypad may also be a virtual keyboard presented on the display or an externally coupled keyboard.

[0152] The communication device 200 may also include one or more mechanisms for sharing and / or obtaining data. For example, the communication device 200 may include a short-range radio frequency (RF) transceiver and / or interrogator, and thus may share data with and / or obtain data from electronic devices based on RF techniques. The communication device 200 may include other short-range transceivers, such as infrared (IR) transceivers, Bluetooth TM Wireless technology Bluetooth TM(BT) transceiver, wireless universal serial bus (USB) transceiver, Bluetooth TM Low energy transceiver, ZigBee transceiver, ANT transceiver, cellular device to device transceiver, wireless LAN link transceiver and / or any other short-range radio technology. The communication device 200, in particular the short-range transceiver, can be capable of sending data to and / or receiving data from electronic devices near the device, such as within 10 meters. The communication device 200 including a Wi-Fi or wireless LAN modem can also be capable of sending and / or receiving data from electronic devices according to various wireless network technologies, including 6LoWpan, Wi-Fi, Wi-Fi low power, WLAN technology, such as IEEE 802.11 technology, IEEE 802.15 technology, IEEE 802.16 technology, etc.

[0153] The communication device 200 may include a memory that can store information elements related to the mobile subscriber, such as one or more subscriber identity modules (SIMs), one or more universal subscriber identity modules (USIMs), one or more removable user identity modules (R-UIMs), one or more eUICCs, one or more UICCs, etc. In addition, the communication device 200 may include other removable and / or fixed memories. The communication device 200 may include volatile memory and / or non-volatile memory. For example, the volatile memory may include random access memory (RAM), including dynamic and / or static RAM, on-chip or off-chip cache memory, etc. Non-volatile memory (which may be embedded and / or removable) may include, for example, read-only memory, flash memory, magnetic storage devices (e.g., hard disks, floppy disk drives, tapes), optical drives and / or media, non-volatile random access memory (NVRAM), etc. Like volatile memory, non-volatile memory may include a cache area for temporarily storing data. At least a portion of the volatile and / or non-volatile memory may be embedded in the processor. The memory may store one or more software programs, instructions, pieces of information, data, etc. that may be used by the apparatus to perform the operations disclosed herein.

[0154] The memory may include an identifier, such as an International Mobile Equipment Identity (IMEI) code, that can uniquely identify the communication device 200. The memory may include an identifier, such as an International Mobile Equipment Identity (IMEI) code, that can uniquely identify the communication device 200. In an example embodiment, the processor may be configured using computer code stored in the memory to cause the processor to perform the operations disclosed herein.

[0155] Some embodiments disclosed herein may be implemented using software, hardware, application logic, or a combination of software, hardware, and application logic. For example, the software, application logic, and / or hardware may reside in a memory, a processor, or an electronic component. In some example embodiments, the application logic, software, or instruction set is maintained on any of a variety of conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any non-transitory medium that can contain, store, communicate, propagate, or transmit instructions for use by or in conjunction with an instruction execution system, apparatus, or device (such as a computer or data processor circuit system), such as a computer or data processor circuit system. Figure 2 As shown, computer-readable media may include non-transitory computer-readable storage media, which may be any media that can contain or store instructions for use by or in connection with an instruction execution system or device, such as a computer.

[0156] In some embodiments, the communication device 200 (i.e., a user equipment (UE) in a network) includes a processor (e.g., at least one data processing entity 201) and a memory (e.g., at least one memory 202). The memory includes a memory that causes the communication device 200 to perform the following operations according to the reference Figure 7 The method described is performed by a computer program code.

[0157] Figure 3 An example embodiment of a control device for a communication system is shown, the control device being coupled to and / or used to control core network functions such as AMF / SMF. Other examples of control devices may be coupled to and / or used to control a station of an access system, such as a RAN node, such as a base station, eNB or gNB, a relay node or a core network node, such as an MME or S-GW or P-GW, or a core network function, such as AMF / SMF, or a server or host. The method may be implemented in a single control device or across more than one control device. The control device may be integrated with a node or module of a core network or RAN or located externally thereto. In some embodiments, the base station includes a separate control device unit or module. In other embodiments, the control device may be another network element, such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such a control device and a control device provided in a radio network controller. The control device 300 may be arranged to provide control of communications in a service area of ​​the system. The control device 300 includes at least one memory 301, at least one data processing unit 302, 303 and an input / output interface 304. Via the interface, the control device may be coupled to a receiver and a transmitter of the base station.The receiver and / or the transmitter may be implemented as a radio front end or a remote radio head.

[0158] Typically, the control device 300 has an antenna for sending and receiving radio signals. A radio frequency (RF) transceiver module coupled to the antenna receives the RF signal from the antenna, converts it to a baseband signal and sends it to a processor (e.g., at least one data processing unit 302, 303). The RF transceiver also converts the baseband signal received from the processor to an RF signal and sends it to the antenna. The processor processes the received baseband signal and calls different functional modules to perform features in the control device 300. A memory (e.g., at least one memory 301) stores program instructions and data for controlling the operation of the control device 300. In Figure 3 In the example of , the control device 300 also includes a protocol stack and a collection of control function modules and circuits. The PDU session processing circuit processes the PDU session establishment and modification process. The policy control module configures policy rules for the UE. The configuration and control circuits provide different parameters to configure and control relevant functions of the UE, including mobility management and session management. For example, suitable processors include dedicated processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application specific integrated circuits (ASICs), file programmable gate arrays (FPGAs) circuits, and other types of integrated circuits (ICs) and / or state machines.

[0159] In some embodiments, the control device 300 (i.e., a base station or a wireless transmission and / or reception point device) includes a processor (e.g., at least one data processing unit 302, 303) and a memory (e.g., at least one memory 301). The memory includes a memory that causes the control device 300 to perform the following reference Figure 8 The method is further described as a computer program code for executing the processing.

[0160] Figure 4 A schematic diagram of an example communication system 400 is shown. The system includes a terminal device (e.g., user equipment) 410, which communicates with an access point 420 via a first interface Y1. The access point 420 communicates with a gateway function 430 (e.g., a non-3GPP interworking function N3IWF) via a second interface 2Y. The gateway function 430 communicates with a core network function. Specifically, it communicates with an access and mobility management function (AMF) 440 via a third interface (N2). The gateway function 430 also communicates with a user plane function (UPF) 450. The gateway function 430 provides access to the core network via the access point 420 for the terminal device 410.

[0161] Figure 4 The example of shows a gateway function 430 in the form of N3IWF, which provides untrusted access. Other non-limiting examples of gateway functions include a trusted non-3GPP gateway function TNGF.

[0162] Figure 5 A diagram showing a communication flow between a terminal device and a network device according to an embodiment is shown. In this example, the communication of a user equipment UE is shown via a (trusted or untrusted) non-3GPP access point and a candidate gateway function and a core network function, wherein the core network function determines whether to allow or deny access to the core network via the candidate gateway function. If denied, it indicates the reason for the denial.

[0163] In step 1a, the UE connects to a non-3GPP access point through an authentication process. It is usually assigned an IP address.

[0164] In step 1b, in order for the UE to attach to the 5GC network, the UE selects N3IWF (in the case of untrusted access) or TNGF (in the case of trusted access) in the 5G Public Land Mobile Network (PLMN). The details of the selection of N3IFW are described in TS23.501 Section 6.3.6.

[0165] In step 2-5, the UE proceeds to establish an IPsec security association (SA) with the selected TNGF or N3IWF. Additionally or alternatively, it initiates an IKE_AUTH authentication process (according to the definition specifications of the selected TNGF and N3IWF).

[0166] In step 6, the TNGF or N3IWF selects an AMF based on the received access point parameters and local policy, as described in 3GPP TS 23.501 clause 6.3.5. The TNGF or N3IWF shall then forward the registration request received from the UE to the selected AMF within the N2 message.

[0167] In steps 7 and 8, the AMF may verify the identity and authentication of the UE using the authentication server function AUSF.

[0168] Therefore, the core network function receives a request from the terminal device via the gateway function. In this case, the request includes an authentication request.

[0169] In the example shown, the core network function (AMF) obtains the gateway slice information of the N3IWF, which indicates the slices supported by the N3IWF. The AMF also retrieves the terminal slice information, which indicates the slices required by the terminal device. Based on the overlap between the gateway slice information and the terminal slice information, the AMF can determine a subset of the (requested) slices that will be indicated as supported (or rejected).

[0170] For example, AMF obtains slice subscription information from Unified Data Management (UDM) and obtains allow / reject NSSAI from Network Slice Selection Function (NSSF). Slice information can be indicated by Network Slice Selection Assistance Information (NSSAI).

[0171] The AMF then determines that the TNGF or N3IWF selected by the UE does not support the slicing requirement. In step 9, the AMF rejects the UE's registration. The Extensible Authentication Protocol (EAP) message within the Registration Reject conveys the rejection reason (e.g., "the selected TNGF slice is not suitable / invalid" or "the selected N3IWF slice is not suitable / invalid"). The UE can then restart the discovery and selection of another TNGF or N3IWF. The request response includes an authentication response.

[0172] In some embodiments, the AMF may transmit information indicating another suitable TNGF or N3IWF that can meet the NSSAI requirements of the UE, i.e., terminal slice information. The UE may then directly connect to the provided TNGF or N3IWF.

[0173] In summary, the gateway function (TNGF or N3IWF) selects the core network function (AMF) to proceed with the UE's registration with the 5GS. The AMF (from the network slice selection function NSSF) receives the UE's allow / reject NSSAI. Since it also knows the (multiple) S-NSSAI supported by the TNGF or N3IWF, it can determine whether the UE's initial TNGF or N3IWF selection is inappropriate based on the slicing requirements. The registration is rejected, and the AMF can insert an indication of the rejection reason (e.g., a reason code) to indicate to the UE that the selected TNGF / N3IWF does not meet the terminal's slicing requirements.

[0174] In addition to this information, the AMF may also propose one or more suitable alternative TNGF / N3IWFs to which the UE may (seek to) connect.

[0175] The UE may restart the TNGF / N3IWF discovery and selection process, or if the AMF proposes any (multiple) TNGF / (multiple) N3IWF, the UE may directly select the TNGF / N3IWF provided by the AMF.

[0176] Figure 6 A diagram showing a communication flow between elements according to another embodiment is shown. In this example, communication of a user equipment UE is shown via a (trusted or untrusted) non-3GPP access point with a candidate gateway function for accessing a core network, wherein the candidate gateway function determines whether to allow or deny access to the core network via the candidate gateway function. If denied, it indicates the reason for the denial.

[0177] In step 1a, the UE connects to a non-3GPP access point through an authentication process. It is usually assigned an IP address.

[0178] In step 1b, in order for the UE to attach to the 5GC network, the UE selects a candidate gateway function in the 5G PLMN, such as N3IWF, as described in TS23.501 clause 6.3.6. Alternatively, for trusted access, it may select TNGF.

[0179] In steps 2 and 3, the UE proceeds to establish an IPsec security association (SA) with the selected N3IWF (or TNGF). In particular, it may initiate an IKE_AUTH authentication process (according to the definition specification of the TNGF or N3IWF).

[0180] In step 4, an EAP / signaling request is sent from the N3IWF (or TNGF) to the UE.

[0181] In step 5, the UE replies to the TNGF / N3IWF with an EAP response. In this response, the UE may send the requested NSSAI to the TNGF / N3IWF according to the operator's policy on NSSAI inclusion in the AS (3GPP TS 23.501, Section 5.15.9). Alternatively, the requested NSSAI may be provided via other L2 messages (security transactions).

[0182] In step 6, based on the requested NSSAI information (list of (multiple) S-NSSAIs), the TNGF / N3IWF may determine that it cannot support any (multiple) S-NSSAIs requested by the UE. It then simply "rejects" the UE's request with a reason code indicating that the TNGF / N3IWF is not suitable for the slices that the UE wants to use.

[0183] The UE then initiates the discovery and selection of another TNGF / N3IWF.

[0184] In summary, this embodiment provides a UE that (when selecting TNGF / N3IWF) discloses a list of (multiple) S-NSSAIs it wants to use. When TNGF / N3IWF finds that it does not support the requested (multiple) S-NSSAIs, TNGF / N3IWF can simply reject the UE request.

[0185] This reduces the signaling process and thus helps improve efficiency. The UE can reselect the TNGF / N3IWF even before initiating any AMF connection. The reselection may be triggered based on the requested NSSAI rather than the allowed NSSAI.

[0186] Figure 7A flow chart of a method 700 according to one aspect is shown. The method 700 is used to operate a terminal device in a communication network having a core network and an access point. Examples of networks include 3GPP core networks, such as 5GC networks. Examples of access points include non-3GPP access points. Examples of gateway functions include trusted non-3GPP access functions or non-trusted non-3GPP access functions, such as trusted non-3GPP gateway functions (TNGF) or non-3GPP interworking functions (N3IWF). Examples of core network functions include access and mobility management functions (AMF).

[0187] The method 700 includes determining (at step 710) one or more candidate gateway functions for accessing a core network via an access point.

[0188] The method 700 also includes (at step 720) sending a request to one or more candidate gateway functions or core network functions for accessing the core network using one or more gateway functions. For example, the request may indicate a set of one or more slices determined by the user equipment for use by the terminal device. The slice may be identified by corresponding single network slice selection assistance information (S-NSSAI).

[0189] The method 700 also includes (at step 730) receiving a request response from the gateway function or from the core network function for each candidate gateway function. The request response is configured to indicate whether access to the core network via the corresponding gateway function is denied, and in the case of denial, to indicate the denial reason. For example, the denial reason may include that the gateway function does not support one or more indicated slices. For example, the request response may indicate a subset of the slices of the determined set, for which access via the corresponding gateway function is denied (or allowed).

[0190] For each of the candidate gateway functions, steps 720 and 730 may be repeated. Such repetitions may occur in parallel or sequentially with each other.

[0191] Figure 8 A flow chart of a method 800 is shown. The method 800 is used to operate a network device in a communication network. The communication network includes a core network and an access point.

[0192] As described above, examples of networks include 3GPP core networks, such as 5GC networks. Examples of access points include non-3GPP access points. Examples of gateway functions include trusted non-3GPP access functions or non-trusted non-3GPP access functions, such as trusted non-3GPP gateway functions (TNGF) or non-3GPP interworking functions (N3IWF). Examples of core network functions include access and mobility management functions (AMF).

[0193] The method 800 includes (at step 810) receiving a request for a terminal device to use a gateway function when accessing a core network via an access point. For example, the request may indicate a set of one or more slices determined by the user equipment for use by the terminal device. The slice may be identified by corresponding single network slice selection assistance information (S-NSSAI).

[0194] In some examples, method 800 may include an optional step 820 (shown in dashed lines), namely determining a subset of slices in the indicated set to which access is denied (or allowed). The determination of the subset includes obtaining gateway slice information for the requested gateway function, and retrieving terminal slice information from the received request based on the indicated set of one or more slices: determining a slice subset based on an overlap between the gateway slice information and the terminal slice information.

[0195] The method 800 also includes (at step 830) sending a request response to the terminal device, the request response being configured to indicate whether access to the core network via the gateway function is denied, and in the case of denial, indicating the denial reason. For example, the denial reason may include that the gateway function does not support one or more indicated slices.

[0196] In the case of performing optional step 820, the request response may indicate a subset of slices of the determined set, for which access via the corresponding gateway function is denied (or allowed).

[0197] Fig. 9 A diagram showing a communication flow between a terminal device and a network device according to another embodiment. In this example, the UE contacts multiple candidate gateway functions. The request is sent to the 5GC, which determines how to respond to the request, including determining a rejection reason.

[0198] The communication flow starts with steps 1-6, which correspond to steps 1-6 defined in clause 6.13.2.1 of 3GPP TR 23700-17:

[0199] In step 1, the UE performs discovery of candidate N3IWFs in accordance with section 6.3.6 of 3GPP TS23.501 (Rel-17), including PLMN selection (possibly taking into account the need to select N3IWF in the local country), and including selection between N3IWF and EPDG, until the UE receives the IP address of the candidate N3IWF from the DNS; using the S-NAPTR DNS procedure, the UE can discover which N3IWF supports the slice support acquisition request process based on the dedicated S-NAPTR "service parameters" (equivalent to "x-3gpp-sgw:x-s5-gtp" defined in 3gpp TS29.303).

[0200] In step 2, the UE sends a slice support acquisition request to the first candidate N3IWF. The slice support acquisition request may optionally contain the slice set (S-NSSAI) that the UE wants to use (indicating to the N3IWF that it does not need to respond with slices outside of this set).

[0201] In step 3, the (first) N3IWF sends a Slice Support Acquisition Response containing the slice set (S-NSSAI) supported by the N3IWF. The slice set (S-NSSAI) is limited to the slice subset (S-NSSAI) indicated by the UE in the Slice Support Acquisition Request. It may also contain cache information to inform the UE how long the UE should consider this information valid.

[0202] As steps 4 and 5, steps 2 and 3 are repeated for the second candidate N3IWF.

[0203] The slice support acquisition service can be designed as an (HTTP) API exposed by the N3IWF to the UE and defined by 3GPP. From steps 2 to 5, a transport layer security (TLS) connection can be used between the UE and the N3IWF. The slice support acquisition service does not represent a change in the state of the N3IWF (because the UE is just acquiring information). It is assumed that the N3IWF provides a server certificate through IKE in the R17 specification.

[0204] In step 6, the UE selects the N3IWF it will contact to access the 5GC based on the information received from the N3IWF in the slice support acquisition response. In this case, the request includes an authentication request, and the UE sends the authentication request to the core network function via the selected gateway function.

[0205] Therefore, steps 1-6 correspond to the corresponding steps defined in 3GPP TR 23700-17 clause 6.13.2.1:

[0206] In step 7, according to 3GPP 23.502 (Rel-17) section 4.12.2.2 step 2-7, the UE connects to the 5GC through the selected N3IWF, which is the first candidate (N3IWF1). It should be noted that in this embodiment (selecting a suitable gateway function before initiating registration with the core network function), the Internet Key Exchange Security Association Initialization (IKE_SA_Init) process, which requires a lot of calculations, is only run once, thereby reducing the calculation requirements.

[0207] It should be noted that when the UE contacts the N3IWF based on the currently configured information, the N3IWF may also be selected based on the tracking area.

[0208] In step 8, AMF may verify the identity and authentication of the UE using AUSF. AMF obtains slice subscription information from UDM and obtains allow / reject NSSAI from NSSF. AMF determines that the N3IWF selected by the UE does not support the slice requirement.

[0209] In step 9, the AMF rejects the registration of the UE. The registration rejection conveys a specific reason. Examples of such indications of rejection reasons include "The selected N3IWF does not comply with the allowed NSSAI". In addition, the AMF may optionally provide information about another suitable alternative N3IWF (FQDN or (multiple) IP addresses) that may satisfy the NSSAI requirements of the UE. Fig. 9 In the example, the indication to replace N3IWF is designed as "alt_N3IWF".

[0210] Therefore, in step 9, the UE receives a request response from the core network function, which is a response to the request sent to the core network function. The request response is configured to indicate whether the connection access to the core network via the corresponding gateway function is denied, and indicates the denial reason in the case of denial.

[0211] In step 10, the UE may restart the discovery and selection of another / alternative N3IWF based on the information received from the AMF.

[0212] It should be understood that these devices may include or be coupled to other units or modules for transmission and / or reception, such as radio components or radio heads. Although these devices are described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

[0213] Note that while embodiments have been described for LTE and 5G NR, similar principles may also be applied to other networks and communication systems that need to perform fast connection reestablishment. Thus, while certain embodiments are described above by way of example with reference to certain example architectures of wireless networks, technologies, and standards, the embodiments may be applied to any other suitable form of communication system other than that shown and described herein.

[0214] It is also noted herein that while the above describes exemplary embodiments, there are numerous variations and modifications which may be made to the disclosed solution without departing from the scope of the subject disclosure.

[0215] In general, various exemplary embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects of the subject disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device, but the subject disclosure is not limited thereto. Although various aspects of the subject disclosure may be shown and described as block diagrams, flow charts, or using some other graphical representation, it is well understood that, as non-limiting examples, these blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof.

[0216] The example embodiments disclosed in the subject matter may be implemented by computer software executable by a data processor of a mobile device, such as in a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products, including software routines, applets and / or macros) may be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. A computer program product may include one or more computer executable components that are configured to perform an embodiment when the program is run. One or more computer executable components may be at least one software code or a portion thereof.

[0217] Furthermore, in this regard, it should be noted that any block of the logic flow shown in the figure can represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, boxes and functions. The software can be stored on physical media such as memory chips or memory blocks implemented in a processor, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants CDs. Physical media are non-transient media.

[0218] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment and may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an FPGA, a gate-level circuit, and a processor based on a multi-core processor architecture, as non-limiting examples.

[0219] Example embodiments of the subject disclosure may be implemented in various components such as integrated circuit modules. The design of integrated circuits is generally a highly automated process. Complex and powerful software tools are available to convert logic level designs into semiconductor circuit designs for etching and formation on semiconductor substrates.

[0220] The foregoing description provides a complete and informative description of exemplary embodiments of the subject disclosure by way of non-limiting examples. However, when read in conjunction with the accompanying drawings and the appended claims, various modifications and adaptations may be apparent to those skilled in the relevant art in view of the foregoing description. However, all of these and similar modifications of the teachings of the subject disclosure will still fall within the scope of the subject disclosure as defined in the appended claims. In fact, there are additional embodiments that may include a combination of one or more embodiments with any other embodiments previously discussed.

Claims

1. A method for operating a terminal device, the method comprising: selecting a candidate gateway function for accessing a core network via an access point; Sending a request for use of the candidate gateway function to the candidate gateway function or to a network function of the core network; as well as A response to the request is received from the candidate gateway function, or from the network function of the core network, the response comprising: an indication that access to the core network via the gateway function is denied, and an indication of a reason for rejection of the request, wherein the indication of the reason for rejection indicates that the candidate gateway function does not support one or more network slices.

2. The method according to claim 1, wherein the candidate gateway functions include: Non-3GPP Interworking Function (N3IWF), or Trusted Non-3GPP Gateway Function (TNGF).

3. The method according to claim 1 or 2, further comprising: determining a set of one or more network slices for use by the terminal device, and The request includes: an identifier of the set of one or more network slices.

4. The method of claim 3, wherein each of the one or more network slices is identified by corresponding single network slice assistance information (S-NSSAI).

5. The method according to claim 3 or 4, wherein the response comprises: An identifier of a subset of network slices in the set of one or more network slices determined for use by the terminal device.

6. The method of any one of claims 1 to 5, wherein the request comprises a registration request and the response comprises a registration response.

7. The method according to any one of claims 1 to 5, wherein the request comprises an authentication request and the response comprises an authentication response.

8. The method according to any one of claims 1 to 7, wherein the network function of the core network comprises: Access and Mobility Management Function (AMF).

9. A method comprising: receiving, by a network device, a request for accessing a core network via an access point of a communication network using a gateway function; as well as The network device sends a response to the request, the response comprising: an indication that access by the terminal device to the core network via the gateway function using the gateway function is denied, and an indication of a reason for rejection of the request, wherein the indication of the reason for rejection indicates that the candidate gateway function does not support one or more network slices.

10. The method according to claim 9, wherein the gateway function comprises: Non-3GPP Interworking Function (N3IWF), or Trusted Non-3GPP Gateway Function (TNGF).

11. The method according to claim 9 or 10, wherein the request comprises: An identifier of a set of one or more network slices for use by the terminal device.

12. The method of claim 11, wherein each of the one or more network slices is identified by corresponding single network slice selection assistance information (S-NSSAI).

13. The method according to claim 11 or 12, further comprising: Determining a subset of network slices in the set of one or more network slices for use by the terminal device, and wherein the response includes: an identifier of the determined subset.

14. The method of claim 13, wherein said determining said subset comprises: The network device obtains gateway slice information for the gateway function; Retrieving, by the network device, terminal slice information based on the identifier of the set of one or more network slices; as well as The network device determines a subset of the network slice based on the overlap between the gateway slice information and the terminal slice information.

15. The method according to claim 14, further comprising: In response to determining that the overlap is a true subset of the indicated set, an alternative gateway function is identified based on the terminal slice information, and wherein the request response is configured to indicate the alternative gateway function.

16. The method according to any one of claims 9 to 15, wherein the network device comprises the gateway functionality.

17. The method according to claim 16, further comprising: The network device sends an authentication request for authentication of the terminal device to an access and mobility management function (AMF); receiving, by the network device from the AMF, an authentication response, the authentication response comprising: the indication of the rejection reason; as well as The indication of the reason for the rejection is included in the response sent to the terminal device.

18. The method according to any one of claims 9 to 13, wherein the network device comprises a network function of the core network.

19. The method of claim 17, wherein the request comprises a registration request and the response comprises a registration response.

20. The method of claim 17, wherein the request comprises an authentication request and the response comprises an authentication response.

21. The method according to any one of claims 18 to 20, wherein the network function of the core network comprises: Access and Mobility Management Function (AMF).

22. A terminal device for use in a communication network comprising a core network and an access point, the terminal device comprising: at least one processor; as well as At least one memory comprises computer program code, wherein when the computer program code is executed by the at least one processor, the terminal device performs the method according to any one of claims 1 to 8.

23. A network device for a communication network including a core network and an access point, the network device comprising: at least one processor; as well as At least one memory comprising computer program code, wherein the computer program code, when executed by the at least one processor, causes the network device to perform the method according to any one of claims 9 to 21.

24. A non-transitory computer-readable medium comprising computer-executable instructions, which, when executed by at least one processor of a terminal device, cause the terminal device to perform the method according to any one of claims 1 to 8.

25. A non-transitory computer-readable medium comprising computer-executable instructions which, when executed by at least one processor of a network device, cause the network device to perform the method of any one of claims 9 to 21.

26. A computer program comprising computer executable instructions, which, when executed by a terminal device, cause the terminal device to execute the method according to any one of claims 1 to 8.

27. A computer program comprising computer executable instructions, which, when executed by a network device, cause the terminal device to perform the method according to any one of claims 9 to 21.

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