Method and system for managing discovery of edge application servers

Abstract

The invention provides a method and a system for managing discovery of edge application servers. A method executed by a centralized edge enabler server (EES) in an edge computing system, the method comprising: loading an edge application server (EAS) as an application programming interface (API) caller to a common API framework (CAPIF) core function; the CAPIF core function is used for authenticating the EAS; discovering, via the CAPIF core function, at least one service API issued by the EAS and obtaining information including an endpoint address of an API exposure function; and invoking the at least one service API based on the endpoint address of the API exposure function.

Description

[0001] This application is a divisional application of the invention patent application with the application date of November 2, 2020, Chinese application number 202080075847.X, and invention name “Method and system for managing discovery of edge application servers”. Technical Field

[0002] The present disclosure relates to wireless communication systems, and more particularly, to systems and methods for managing discovery of edge application servers. This application is based on and claims the benefit of Indian application No. 201941044495 filed on November 2, 2019 and No. 201941045559 filed on November 8, 2019, the disclosures of which are incorporated herein by reference. Background Art

[0003] In order to meet the increased demand for wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop improved 5G or quasi-5G communication systems. Therefore, 5G or quasi-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems". 5G communication systems are considered to be implemented in higher frequency (millimeter wave) bands (such as the 60GHz band) in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed in 5G communication systems. In addition, in 5G communication systems, development of system network improvements is being carried out based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, collaborative communications, collaborative multi-point (CoMP), receiving-end interference elimination, etc. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0004] The Internet, which is a human-centered connected network in which people generate and consume information, is now evolving into the Internet of Things (IoT), in which distributed entities (such as things) exchange and process information without human intervention. Through connection with cloud servers, the Internet of Everything (IoE), which combines IoT technology with big data processing technology, has emerged. Because the realization of IoT requires technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology" and "security technology", sensor networks, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied recently. Such an IoT environment can provide intelligent Internet technology services that create new value for human life by collecting and analyzing data generated between connected things. Through the integration and combination between existing information technology (IT) and various industrial applications, IoT can be applied to various fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart appliances and advanced medical services.

[0005] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine type communications (MTC), and machine-to-machine (M2M) communications can be implemented through beamforming, MIMO, and array antennas. Cloud radio access networks (RANs) as an application of the above-mentioned big data processing technologies can also be considered as an example of the convergence between 5G technologies and IoT technologies.

[0006] Edge computing systems are distributed computing paradigms that bring computing and data storage closer to the geographic locations where computing and data storage are needed to improve response time and save bandwidth. Application servers running on edge data networks in edge computing systems are called edge application servers, where edge application servers have different availability on different edge data networks. Due to operational and cost constraints, the deployment of edge application servers throughout the edge data network may be inconsistent.

[0007] Figure 1A general architecture of an edge computing system (1000) for enabling an edge application server (310) in a 3GPP network (200) according to the prior art is shown. Functional entities in the architecture include an edge enabler server (320), an edge application server (310), an edge enabler client (120), an application client (110), and an edge configuration server (400). The edge enabler server (320) and the edge application server (310) are part of an edge data network (300) of the edge computing system (1000), while the edge enabler client (120) and the application client (110) are part of a user equipment (UE) 100. The edge application server (310) is registered to the edge enabler server (320) through a reference point (i.e., edge (3)). In addition, the edge enabler server (320) maintains a registry of edge application servers (310). In addition, the edge enabler server (310) is registered with the edge configuration server (400) and provides a registry to the edge configuration server (400) through a reference point (ie, edge (6)) for purposes such as service continuity.

[0008] In addition, the edge enabler client (120) provides support functions required by the application client (110) via a reference point (i.e., edge (5)). The edge configuration server (400) provides support functions to the edge enabler client (120) via a reference point (i.e., edge (4)), wherein the support functions allow the UE (100) to establish a connection with the edge enabler server (320) via a reference point (i.e., edge (1)). The edge enabler server (320) provides support functions required by the edge application server (310) to operate in the edge data network (300). The edge enabler server (320) is deployed within a local data network access point that is geographically close to the point of attachment of the UE (100). The edge application server (310) and the edge enabler server (320) provide support functions to the 3GPP network (200) via edge (7) and edge (2), respectively, wherein edge (7) and edge (2) are reference points. When a connection is established between a UE (100) and an edge data network (300) through a 3GPP network (200), an application client (110) accesses required data or services from an edge application server (310) through an interface called application data traffic (500).

[0009] Generally, the UE (100) checks the availability of the edge application server (310) from the edge enabler server (320) before attempting to utilize services from the edge application server (310). A variety of discovery methods can be used to determine the availability of the edge enabler server (320) at the edge data network (300). However, the design of such methods is specific to the needs of deploying the edge application server (310) at the edge data network (300). For the service provider of the edge system (1000), the choice of discovery method is a critical business or technical decision.

[0010] Consider an example scenario in which a UE (100) is connected to a first edge data network at a first location and accesses an online video service supported by the first edge data network. Additionally, the UE (100) is relocated from the first location to a second location that includes a second edge data network, where the second edge data network also supports the online video service. The UE (100) may not be aware of the second edge data network at the second location. The UE (100) does not switch to the second edge data network and continues to access the online video service from the first edge data network. Due to being away from the first location, the latency of the UE (100) accessing the online video service from the first edge data network increases, which deteriorates the user's online video viewing experience.

[0011] In addition, the UE (100) includes a single network slice selection identifier (S-NSSAI) for multiple subscriptions. The subscribed S-NSSAI is provided based on subscriber information that the UE (100) subscribes to for use in a public land mobile network (PLMN). Certain subscribed S-NSSAIs are subject to network slice specific authentication and authorization procedures. The network slice specific authentication and authorization procedures are performed by an authentication, authorization and accounting server (AAA-S). The network slice specific authentication and authorization procedures occur between an EAP client on the UE (100) and an EAP server on the AAA-S. For S-NSSAIs that require the PLMN to utilize an authentication, authorization and accounting server (AAA-S) to perform slice-specific authentication and authorization, the network slice specific authentication and authorization procedures will be triggered by an access and mobility function (AMF). The home PLMN (H-PLMN) operator or a third party having a business relationship with the H-PLMN hosts the AAA-S. When the network slice specific authentication and authorization is successful for the S-NSSAI, the S-NSSAI is sent to the UE (100) in an allowed network slice selection identifier (NSSAI) in a configuration update command message or a registration accept. The allowed NSSAI is an NSSAI provided by the serving PLMN during the registration process, or an NSSAI indicating an S-NSSAI value that the UE (100) can use in the serving PLMN of the current registration area. The UE (100) is allowed to access services related to the S-NSSAI. For example, the UE (100) can establish a protocol data unit (PDU) session related to the S-NSSAI and access the service through the PDU session.

[0012] Certain UEs and access and mobility management functions AMF have the capability to support network slice specific authentication and authorization procedures. A UE that supports network slice specific authentication and authorization procedures shall indicate the UE's capabilities to the AMF. However, an AMF that supports network slice specific authentication and authorization procedures shall not indicate the AMF's capabilities to the UE. The UE (100) sends a registration request message including a request for NSSAI to the AMF. When network slice specific authentication and authorization fail for all S-NSSAIs in the allowed NSSAIs, the AMF performs a network initiated de-registration procedure described in clause 4.2.2.3.3 of 3GPP specification TS23.502. In addition, the AMF includes a list of rejected S-NSSAIs with appropriate rejection cause values ​​in the explicit de-registration request message. However, for a scenario in which the UE (100) has a PDU session for an emergency, the behavior of the UE (100) and the network is undefined. In addition, it is unclear how the UE supports systems other than fifth generation systems (e.g., Evolved Packet System (EPS)) to handle such a scenario.

[0013] Therefore, it is desirable to address the above-mentioned shortcomings or other deficiencies, or at least provide a useful alternative. Summary of the invention

[0014] Technical issues

[0015] The main purpose of the embodiments of this document is to provide a method and system for managing the discovery of edge application servers.

[0016] Another object of the embodiments of this invention is to provide a method for assisting a UE in selecting a correct discovery method. Thus, the UE can adjust its behavior according to the selected discovery method and use the discovery method to determine the availability of an edge application server in an edge data network.

[0017] Another object of the embodiments of the present invention is to provide a centralized edge enabler server for obtaining information about service APIs of all edge application servers of all edge data networks. In addition, in response to receiving a request for relocation of an application context from a first edge data network, the centralized edge enabler server can provide information about service APIs available at a second edge data network to the first edge data network. Therefore, the first edge data network can transmit the application context to the second edge data network to allow the UE to access the service with low latency.

[0018] Another object of embodiments herein is to provide a method for handling a PDU session during emergency services.

[0019] Solution to the problem

[0020] Therefore, an embodiment of the present invention provides a method for managing the discovery of an edge application server (310). The method includes sending an initial service provisioning request by an edge enabler client (120) of a UE (100) to an edge configuration server (400). In addition, the method includes receiving an initial service provisioning response including an information element from an edge configuration server (400) by the edge enabler client (120) of the UE (100), wherein the information element indicates a supported discovery mode. In addition, the method includes sending a request for discovering an edge application server (310) to at least one of an edge configuration server (400), a dedicated server for edge application server information, and a domain name system (DNS) server by the edge enabler client (120) of the UE (100) based on the supported discovery mode.

[0021] In an embodiment, the discovery mode is specific to at least one of a location of the UE (100) and an application in the UE (100).

[0022] In an embodiment, the method further comprises detecting, by the edge enabler client (120) of the UE (100), that the service provisioning configuration is no longer valid, and sending, by the UE (100), another provisioning request to the edge configuration server (400). In addition, the method comprises discovering, by the edge enabler client (120) of the UE (100), the edge application server using a discovery mode based on the received service provisioning information.

[0023] Therefore, embodiments of the present invention provide a method in which a centrally deployed edge enabler server (620) provides assistance to an edge enabler server (320) deployed in a local data network (300) or an edge enabler client (120) on a UE (100).

[0024] Therefore, an embodiment of the present invention provides a method for managing services provided to at least one of an edge application server (310) and an edge enabler client (120) of a UE (100). The method includes receiving, by a centralized edge enabler server (620), a request message including a service support request from at least one of an edge application server (310) and an edge enabler client (120) of a UE (100). In addition, the method includes configuring, by the centralized edge enabler server (620), a response message including service support information based on the received request message. In addition, the method includes sending, by the centralized edge enabler server (620), a response message including service support information to at least one of an edge application server (310) and an edge enabler client (120) of a UE (100).

[0025] In an embodiment, the method includes allowing, by a centralized edge enabler server (620), an edge application server (310) to publish edge application server information from at least one edge data network (300) based on a response message.

[0026] In an embodiment, the method includes allowing, by a centralized edge enabler server (620), an edge enabler client (120) to discover edge application servers (310) on at least one edge data network (300) based on the response message.

[0027] In an embodiment, the method includes exposing, by a centralized edge enabler server (620), a location reporting API to an edge application server (310) on at least one edge data network (300) based on a response message, and determining a valid location of the UE based on the location reporting API.

[0028] In an embodiment, the method includes exposing, by the centralized edge enabler server (620), a UE identifier API to an edge application server based on a response message to provide a valid UE identifier for the capability exposure API.

[0029] In an embodiment, the method includes enabling, by the centralized edge enabler server (620), subscription of information from the edge enabler client (120) to the centralized edge enabler server (620) based on the response message, wherein the information includes dynamic availability of the edge application server (310).

[0030] In an embodiment, the method includes determining, by a centralized edge enabler server (620), whether to relocate an application context of a UE (120) based on a response message, and providing instructions to an edge application server (310), and configuring, by the edge application server (310), the UE application context to be relocated based on the response message, and transmitting the UE application context to a target edge application server.

[0031] In an embodiment, the method includes providing, by a centralized edge enabler server (620), an IP address of a target edge application server, wherein the IP address serves a UE in motion when a UE application context is relocated.

[0032] In an embodiment, the method includes allowing, by a centralized edge enabler server (620), registration of an edge application server (310) from at least one edge data network (310) based on a response message to provide profile information.

[0033] Therefore, an embodiment of the present invention provides a system (1000) for managing the discovery of edge application servers (310). The system (1000) includes a UE (100), which includes an edge enabler client (120), one or more edge application servers (310) and a centralized edge enabler server (620). The centralized edge enabler server (620) is configured to receive a request message including a service support request from at least one of the edge application server (310) and the edge enabler client (120) of the UE (100). The centralized edge enabler server (620) configures a response message including service support information based on the request message. The centralized edge enabler server (620) sends a response message including service support information to at least one of the edge application server (310) and the edge enabler client (120) of the UE (100).

[0034] Therefore, an embodiment of the present invention provides a method for managing the discovery of edge application servers (310). The method includes receiving, by a centralized edge enabler server (620), a message including service application programming interface (API) publishing and discovery information from at least one edge application server (310). In addition, the method includes performing, by the centralized edge enabler server (620), at least one of the following operations: providing at least one of edge application access to a service API provided by at least one edge application server (310) in an edge data network (300) by providing a public API framework (CAPIF) function based on the received message; and providing at least one of the functions of edge application server service API publishing and discovery response to at least one edge application server (310) based on the received message.

[0035] In an embodiment, at least one of the edge applications is controlled by a third party server and a PLMN operator.

[0036] In an embodiment, at least one of the functions is a CAPIF core function for supporting loading of edge application servers (310), publishing of service APIs of edge application servers, discovery of service APIs of edge application servers, and billing of service API calls of edge application servers.

[0037] In an embodiment, the method includes providing, by the edge application server (310), at least one function for service API publishing and discovery response of the edge application server.

[0038] In an embodiment, the at least one function is an API exposure function, an API publishing function, and an API management function.

[0039] In an embodiment, the API exposure function supports calling of service APIs exposed from the edge application server (310) via CAPIF-2 or CAPIF-2e, and supports billing of service API calls of the edge application server via CAPIF-3.

[0040] In an embodiment, the API publishing function supports the publishing of service APIs of edge applications to the CAPIF core functions of the edge enabler server (320) via CAPIF-4.

[0041] In an embodiment, the API management function supports the management of service APIs of the CAPIF core functions of the edge application server (310) to the edge enabler server (320) via CAPIF-5.

[0042] In an embodiment, the edge application server (310) acts as an API exposing functions and service APIs, wherein the API exposing functions and service APIs are published to the centralized edge enabler server (620), wherein the centralized edge enabler server (620) makes the edge application service APIs available to each other.

[0043] In an embodiment, the edge application server (310) acts as an API caller and is offloaded to the centralized edge enabler server (620).

[0044] In an embodiment, the edge application server (310) authenticates with the centralized edge enabler server (620).

[0045] In an embodiment, the method further comprises discovering, by the edge application server (310), a service API published by the edge application server (310) via a centralized edge enabler server, the service API comprising an endpoint address of an API exposed function at which a service API call is to be executed.

[0046] Therefore, an embodiment of the present invention provides a method for handling a PDU session during an emergency service. The method includes detecting, by an AMF server (800), that a user equipment (UE) (100) has a PDU session for emergency services and that the UE (100) is establishing one of the PDU sessions for emergency services. In addition, the method includes detecting, by the AMF server (800), that network slice authentication and authorization fail for all allowed network slice selection identifiers (NSSAIs). In addition, the method includes, in response to detecting that the UE (100) has a PDU session for emergency services and that the UE (100) is establishing one of the PDU sessions for emergency services, and detecting that network slice authentication and authorization fail for all allowed NSSAIs, the AMF server (800) performs at least one of the following operations: not deregistering the UE (100), and sending a configuration update command including a rejected NSSAI and a rejection reason value to the UE (100).

[0047] In an embodiment, the method further comprises determining, by the AMF server (800), that a PDU session for emergency services is completed. Furthermore, the method comprises, in response to determining that the PDU session for emergency services is completed, deregistering by the AMF server (800) to the UE (100). Furthermore, the method comprises sending, by the AMF server (800), a deregistration request message with a rejection cause value to the UE (100). Furthermore, the method comprises selecting, by the UE (100), a cell on the network and initiating an attachment process to the network based on the deregistration request message. Furthermore, the method comprises disabling, by the UE (100), the N1 mode capability of 3GPP access.

[0048] Therefore, an embodiment of the present invention provides a UE (100) for managing the discovery of an edge application server (310). The UE (100) includes a processor (140), a memory (130), and an edge enabler client (120) coupled to the processor (140) and the memory (130). The edge enabler client (120) is configured to send an initial service provisioning request to an edge configuration server (400). In addition, the edge enabler client (120) is configured to receive an initial service provisioning response including an information element from the edge configuration server (400), wherein the information element indicates a supported discovery mode. In addition, the edge enabler client (120) is configured to send a request for discovering an edge application server (310) to at least one of an edge configuration server (400), a dedicated server for edge application server information, and a domain name system (DNS) server based on the supported discovery mode.

[0049] Therefore, an embodiment of the present invention provides a system (1000) for managing the discovery of edge application servers (310). The system (1000) includes one or more edge application servers (310) and a centralized edge enabler server (620). The centralized edge enabler server (620) is configured to receive a message including service application programming interface (API) publishing and discovery information from at least one edge application server (310). In addition, the centralized edge enabler server (620) is configured to perform at least one of the following operations based on the received message by providing a public API framework (CAPIF) function: providing at least one of edge application access to a service API provided by at least one edge application server (310) in an edge data network (300); and providing at least one of the functions of edge application server service API publishing and discovery response to at least one edge application server (310) based on the received message.

[0050] Therefore, an embodiment of the present invention provides a system for handling a PDU session during an emergency service. The system includes a UE (100) and an AMF server (800). The AMF server (800) is configured to detect that the UE (100) has a PDU session for emergency services and the UE (100) is establishing one of the PDU sessions for emergency services. In addition, the AMF server (800) is configured to detect that network slice authentication and authorization fail for all allowed network slice selection identifiers (NSSAI). In response to detecting that the UE (100) has a PDU session for emergency services and the UE (100) is establishing one of the PDU sessions for emergency services, and detecting that network slice authentication and authorization fail for all allowed NSSAIs, the AMF server (800) is configured to perform at least one of the following operations: not deregistering the UE (100); and sending a configuration update command including a rejected NSSAI and a rejection reason value to the UE (100).

[0051] Therefore, an embodiment of the present invention provides an AMF server (800) for handling a PDU session during an emergency service. The AMF server includes a processor (810) coupled to a memory (820). The processor (810) is configured to detect that the UE (100) has a PDU session for emergency services and the UE (100) is establishing one of the PDU sessions for emergency services. In addition, the processor (810) is configured to detect that network slice authentication and authorization fail for all allowed NSSAIs. In response to detecting that the UE (100) has a PDU session for emergency services and the UE (100) is establishing one of the PDU sessions for emergency services, and detecting that network slice authentication and authorization fail for all allowed NSSAIs, the processor (810) is configured to perform at least one of the following operations: avoiding registration with the UE (100), and sending a configuration update command including a rejected NSSAI and a rejection reason value #62 to the UE (100).

[0052] Therefore, an embodiment of the present invention provides a UE (100) for handling a PDU session during emergency services. The UE (100) includes a processor (140) coupled to a memory (130). The processor (140) is configured to receive a deregistration request message with a rejection cause value #62 from an AMF server (800). In addition, the processor (140) is configured to select an E-UTRAN cell of a network. In addition, the processor (140) is configured to initiate an attachment process to the network based on the deregistration request message. In addition, the processor (140) is configured to disable the N1 mode capability of the 3GPP access based on the attachment process.

[0053] An embodiment of the present invention provides a method executed by a centralized edge enabler server EES in an edge computing system, the method comprising: loading an edge application server EAS as an application programming interface API caller into a common API framework CAPIF core function; authenticating the EAS using the CAPIF core function; discovering at least one service API published by the EAS via the CAPIF core function, and obtaining information including an endpoint address of an API exposure function; and calling the at least one service API based on the endpoint address of the API exposure function.

[0054] An embodiment of the present invention provides a centralized edge enabler server EES in an edge computing system, wherein the centralized EES includes: a transceiver; and a controller, coupled to the transceiver, and configured to: load an edge application server EAS as an application programming interface API caller into a common API framework CAPIF core function, authenticate the EAS using the CAPIF core function, discover at least one service API published by the EAS via the CAPIF core function, obtain information including an endpoint address of an API exposure function, and call the at least one service API based on the endpoint address of the API exposure function.

[0055] These and other aspects of the embodiments herein will be better understood and appreciated when considered in conjunction with the following description and accompanying drawings. However, it should be understood that although the following description indicates preferred embodiments and a number of specific details therein, these descriptions are illustrative and not restrictive. Various changes and modifications may be made within the scope of the embodiments of the present disclosure without departing from the spirit of the present disclosure, and the embodiments of the present disclosure include all such modifications.

[0056] Advantageous Effects of the Invention

[0057] The main purpose of the embodiments of this document is to provide an effective method and system for managing the discovery of edge application servers.

[0058] Another object of embodiments herein is to provide an efficient method for handling PDU sessions during emergency services. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The method and apparatus are shown in the accompanying drawings, and the same reference numerals indicate corresponding parts in all drawings. With reference to the accompanying drawings, the embodiments of the present invention will be better understood according to the following description, in which:

[0060] Figure 1 The general architecture of an edge computing system (1000) for enabling an edge application server (310) in a 3GPP network according to the prior art is shown;

[0061] Figure 2 is a block diagram of a UE (100) according to an embodiment disclosed herein;

[0062] Figure 3a is a flow chart illustrating a method implemented by a UE (100) for managing discovery of an edge application server (310) according to an embodiment disclosed herein;

[0063] Figure 3b is a flow chart illustrating a method implemented by a centralized edge enabler server (620) for managing discovery of edge application servers (310) according to embodiments disclosed herein;

[0064] Figure 3c is a flow chart illustrating a method for handling a PDU session during emergency services according to an embodiment disclosed herein;

[0065] Figure 3d is a flow chart illustrating a method for managing services provided to at least one of an edge application server (310) and an edge enabler client (120) of a UE (100) according to an embodiment disclosed herein;

[0066] Figure 3e is a flow chart illustrating a method for handling a PDU session during emergency services according to an embodiment disclosed herein;

[0067] Figure 4 shows signaling between a UE (100) and an edge configuration server (400) for supplying a configuration from the edge configuration server (400) to the UE according to an embodiment disclosed herein;

[0068] Figure 5 The architecture of the proposed edge computing system (1000) for enabling edge application servers (310) in a 3GPP network according to the embodiments disclosed herein is shown;

[0069] Figure 6 The architecture of an edge computing system (1000) proposed for publishing and discovering service application programming interfaces (APIs) of edge application servers (310) by using a common API framework (CAPIF) core function according to an embodiment disclosed herein is shown;

[0070] Figure 7 is a timing diagram illustrating a method for managing application context relocation according to an embodiment disclosed herein;

[0071] Figure 8 An overview of a system (1000) for handling PDU sessions during emergency services according to embodiments disclosed herein is shown; and

[0072] Fig. 9 is a block diagram of an AMF server (800) according to an embodiment disclosed herein. DETAILED DESCRIPTION

[0073] The embodiments of the present invention and their various features and advantageous details are explained more fully with reference to the non-limiting embodiments shown in the accompanying drawings and described in detail in the following description. Descriptions of well-known components and processing techniques are omitted so as not to unnecessarily obscure the embodiments of the present invention. In addition, the various embodiments described herein are not necessarily mutually exclusive, because some embodiments can be combined with one or more other embodiments to form new embodiments. Unless otherwise stated, the term "or" used herein refers to a non-exclusive or. The examples used herein are merely to facilitate understanding of the ways in which the embodiments of the present invention can be practiced, and further enable those skilled in the art to practice the embodiments of the present invention. Therefore, these examples should not be interpreted as limiting the scope of the embodiments of the present invention.

[0074] According to the tradition of the art, embodiments can be described and illustrated according to the blocks that perform the described one or more functions. These blocks may be referred to as managers, units, modules, hardware components, etc. in this article, which are physically implemented by analog and / or digital circuits (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hard-wired circuits, etc.), and are optionally driven by firmware. For example, the circuit may be contained in one or more semiconductor chips or on a substrate support such as a printed circuit board. The circuit constituting the block may be implemented by dedicated hardware, or by a processor (for example, one or more programmed microprocessors and associated circuits) or by a combination of dedicated hardware for executing some functions of the block and a processor for executing other functions of the block. Without departing from the scope of the present disclosure, each block of the embodiment may be physically divided into two or more interacting and discrete blocks. Similarly, without departing from the scope of the present disclosure, the block of the embodiment may be physically combined into more complex blocks.

[0075] Therefore, an embodiment of the present invention discloses a method for managing the discovery of an edge application server (310). The method includes sending an initial service provisioning request by an edge enabler client (120) of a UE (100) to an edge configuration server (400). In addition, the method includes receiving an initial service provisioning response including an information element from an edge configuration server (400) by the edge enabler client (120) of the UE (100), wherein the information element indicates a supported discovery mode. In addition, the method includes sending a request for discovering an edge application server (310) to at least one of an edge enabler server (400), a dedicated server for edge application server information, and a domain name system (DNS) server by the edge enabler client (120) of the UE (100) based on the supported discovery mode.

[0076] Unlike existing methods and systems, the proposed method allows the edge computing service provider to assist the UE in selecting the correct discovery method. In addition, the UE can adjust its behavior according to the selected discovery method and use the discovery method to determine the availability of the edge application server in the edge data network. Therefore, the proposed method reduces the complexity of the edge computing system in selecting the correct discovery method to determine the availability of the edge application server in the edge data network.

[0077] Unlike existing methods and systems, a centralized edge enabler server contains information about service APIs of all edge application servers of all edge data networks. In response to receiving a request to relocate an application context, the centralized edge enabler server identifies a second edge data network suitable for transmitting the application context from a first edge data network. The centralized edge enabler server identifies the second edge data network based on information about the service APIs of edge application servers in the second edge data network. Since the application context is transmitted from the first edge data network to the second edge data network, the delay in accessing the service at the UE will be reduced. Therefore, the proposed method improves the user experience due to the reduced delay in accessing the service.

[0078] Now refer to the accompanying drawings, specifically Figures 2 to 9 , showing a preferred embodiment.

[0079] Figure 21 is a block diagram of a UE (100) according to an embodiment disclosed herein. Examples of UE (100) are, but are not limited to, smart phones, tablet computers, personal digital assistants (PDAs), Internet of Things (IoT), immersive devices, virtual reality devices, etc. In an embodiment, the UE (100) includes an application client (110), an edge enabler client (120), a memory (130), a processor (140), a communicator (150), an edge application server discovery controller (160), and an emergency service-based PDU session controller (170). The processor (140) is coupled to the application client (110), the edge enabler client (120), the memory (130), the communicator (150), the edge application server discovery controller (160), and the emergency service-based PDU session controller (170).

[0080] The edge enabler client (120) provides the support functions required by the application client (110) through the reference point (i.e., the edge (5)). The edge application server discovery controller (160) operates together with the edge enabler client (120). The edge application server discovery controller (160) is configured to send an initial service provisioning request to the edge configuration server (400) and receive an initial service provisioning response including an information element from the edge configuration server (400). The information element indicates the supported discovery mode. In addition, the edge application server discovery controller (160) is configured to send a request for discovering the edge application server (310) to at least one of the edge configuration server (400), a dedicated server for edge application server information, and a DNS server based on the supported discovery mode.

[0081] The emergency service based PDU session controller (170) receives a deregistration request message with a rejection cause value #62 from the AMF server (800). In addition, the emergency service based PDU session controller (170) selects an E-UTRAN cell of a network and initiates an attachment procedure to the network based on the deregistration request message. Based on the attachment procedure, the emergency service based PDU session controller (170) disables the N1 mode capability of the 3GPP access.

[0082] The memory (130) may include a non-volatile storage element. Examples of such non-volatile storage elements may include a magnetic hard disk, an optical disk, a floppy disk, a flash memory, or an electrically programmable memory (EPROM) or an electrically erasable programmable memory (EEPROM).

[0083] Additionally, in some examples, the memory (130) may be considered a non-transitory storage medium. The term "non-transitory" may indicate that the storage medium is not contained in a carrier wave or propagating signal. However, the term "non-transitory" should not be interpreted as meaning that the memory (130) is non-removable. In some examples, the memory (130) may be configured to store a larger amount of information than the memory (130), respectively. In certain examples, the non-transitory storage medium may store data that may change over time (e.g., in random access memory (RAM) or cache).

[0084] The processor (140) is configured to execute instructions stored in the memory (130). The communicator (150) is configured to perform internal communication between hardware components in the UE (100) and the server.

[0085] although Figure 2 The hardware components of the UE (100) are shown, but it should be understood that other embodiments are not limited thereto. In other embodiments, the UE (100) may include fewer or more components. In addition, the labels or names of the components are for illustrative purposes only and do not limit the scope of the present invention. One or more components can be combined to perform the same or substantially similar functions for managing the discovery of the edge application server (310).

[0086] Figure 3a Detailed description is a flowchart (S300a) showing a method implemented by a UE (100) for managing discovery of an edge application server (310) of an edge data network (300) according to an embodiment disclosed herein.

[0087] At S302a, the method includes sending, by the edge enabler client (120), an initial service provisioning request to the edge configuration server (400). At S304a, the method includes receiving, by the edge enabler client (120), an initial service provisioning response including an information element from the edge configuration server (400). The information element indicates supported discovery modes. At S306a, the method includes sending, by the edge enabler client (120), a request for discovering edge application servers (310) to at least one of the edge configuration server (400), a dedicated server for edge application server information, and a DNS server based on the supported discovery modes.

[0088] Figure 3b is a flow chart ( S300b ) illustrating a method implemented by a centralized edge enabler server ( 620 ) for managing discovery of edge application servers ( 310 ) according to an embodiment disclosed herein.

[0089] At S302b, the method includes receiving, by a centralized edge enabler server (620), a message including service application programming interface (API) publishing and discovery information from at least one edge application server (310). At S304b, the method includes providing at least one of edge application access to a service API provided by at least one edge application server (310) in the edge data network (300) by providing a public API framework (CAPIF) function based on the received message. At S306b, the method includes providing at least one of functions for edge application server service API publishing and discovery response to at least one edge application server (310) based on the received message.

[0090] Figure 3c is a flowchart (300c) showing a method for handling a PDU session during emergency services according to an embodiment disclosed herein. At S302c, the method includes detecting, by the AMF server (800), that the UE (100) has a PDU session for emergency services and that the UE (100) is establishing one of the PDU sessions for emergency services. At S304c, the method includes detecting, by the AMF server (800), that network slice authentication and authorization have failed for all allowed network slice selection identifiers (NSSAI). At S306c, the method includes avoiding registration by the AMF server to the UE (100). At S308c, the method includes sending a configuration update command to the UE (100) including a rejected NSSAI and a rejection cause value.

[0091] Figure 3d The invention discloses a flow chart (300d) of a method for managing services provided to at least one of an edge application server (310) and an edge enabler client (120) of a UE (100) according to an embodiment disclosed herein. At S302d, the method includes receiving a request message including a service support request from one or more edge application servers (310a and 310b) and a UE (100). At S304d, the method includes configuring a response message including service support information based on the request message. At S306d, the method includes sending a response message including service support information to at least one of an edge application server (310) and an edge enabler client (120) of a UE (100).

[0092] Figure 3eis a flow chart (300e) illustrating a method for handling a PDU session during emergency services according to an embodiment disclosed herein. At S302e, the method includes receiving a deregistration request message with a rejection cause value #62 from an AMF server (800). At S304e, the method includes selecting an E-UTRAN cell of a network. At S306e, the method includes initiating an attachment procedure to the network based on the deregistration request message. At S308e, the method includes disabling N1 mode capabilities of 3GPP access based on the attachment procedure.

[0093] The various actions, behaviors, blocks, steps, etc. in flow charts S300a, S300b, S300c, S300d, and S300e may be performed in the order presented, in a different order, or simultaneously. In addition, in some embodiments, some of these actions, behaviors, blocks, steps, etc. may be omitted, added, modified, or skipped without departing from the scope of the present invention.

[0094] Figure 4 The signaling between the UE (100) and the edge configuration server (400) for supplying the configuration from the edge configuration server (400) to the UE (100) according to the embodiments disclosed herein is shown. Various discovery methods that the UE (100) can use to determine the availability of the edge enabler server (320) at the edge data network (300) are given below:

[0095] 1) Distributed Discovery: The edge enabler client (120) can query the edge enabler server (320) to obtain information about the edge application server (310).

[0096] 2) Centralized discovery: The edge enabler client (120) can query the edge configuration server (400) to obtain information about the edge application server (310).

[0097] 3) Hybrid Discovery: The edge configuration server (400) can redirect the edge enabler client (120) to the edge enabler server (320). In addition, the edge enabler server (320) can provide the edge enabler client (120) with information about the edge application server (310).

[0098] 4) Discovery based on dedicated servers: The edge configuration server (400) can redirect the edge enabler client (120) to a dedicated server. In addition, for information security, the dedicated server can provide information about the edge application server (310).

[0099] 5) DNS-based discovery: The edge enabler client (120) can obtain information about the edge application server (310) by communicating with a dedicated / shared DNS server.

[0100] The edge enabler client (120) performs provisioning of configuration information, ie, information on the edge application server (310) obtained from the edge configuration server (400), to enable communication between the application client (110) and the edge application server (310) having the service.

[0101] In an embodiment, the UE (100) comprises a dedicated edge data network configuration client for receiving configuration information from the edge configuration server (400). In an embodiment, a DNS server may be used to provide a discovery method to the UE (100).

[0102] The proposed method for determining the availability of an edge enabler server (320) at an edge data network (300) is shown in steps 401-402. In step 401, the edge enabler client (120) sends an initial service provisioning request to the edge configuration server (400). In step 402, the edge configuration server (400) sends an initial service provisioning response including configuration information to the UE (100). Table 1 gives the information elements in the configuration information. "Discovery mode" and "Other provisioning related information" are information elements in the configuration information.

[0103] Table 1: Initial service provision response

[0104]

Table 1

[0105] Information Elements state describe Discovery Mode M Supported discovery modes Other supply related information M Other supply related information

[0106] The information element "discovery mode" indicates the discovery methods supported by the edge data network (300). In an embodiment, the discovery mode is specific to at least one of the UE (100), the location of the UE (100), the application, the application type, and the application category.

[0107] In an embodiment, the UE (100) determines the discovery mode based on the configuration information received in the provisioning response. For example, when the initial service provisioning response includes a DNS resolver configuration, the UE (100) determines that the discovery mode supported by the edge data network (300) is DNS-based discovery. In another example, when the initial service provisioning response includes an EAS configuration, the UE (100) determines that the discovery mode supported by the edge data network (300) is centralized discovery.

[0108] In an embodiment, the UE (100) continues to use a discovery mode unless the configuration information is explicitly changed by the edge configuration server (400) or changes due to the UE (100) sending another provisioning request. When the service area of ​​the UE (100) changes, the UE (100) sends another provisioning request.

[0109] In an embodiment, if multiple discovery methods are used in the deployment of edge computing services, and when the edge configuration server (400) distributes information about the edge application server (310) to different edge enabler servers (not shown), the edge configuration server (400) includes information about the entity from which the UE (100) needs to query information about the edge application server (310) and the discovery mode information element.

[0110] Such an implicit determination will fail in the case where the initial service provisioning response includes information about the edge enabler server (320) resulting in two discovery modes. Consider the two discovery modes to be distributed discovery and hybrid discovery. In the case of distributed discovery, the UE (100) needs to direct all future discovery requests to the edge enabler server (320). In the case of hybrid discovery, for all discovery requirements, the initial service provisioning request from the UE (100) should first be directed to the edge configuration server (400). Therefore, having an explicit indication of supported modes as described in the present invention is deterministic.

[0111] The indication of discovery mode in the initial service provisioning response clarifies the course of action of the UE (100). Therefore, the UE (100) can adjust its behavior based on the discovery mode. For example, the UE (100) can decide whether to subscribe to notifications from the edge enabler server (320) or the edge configuration server (400) based on the initial service provisioning response. The server names used herein are for illustrative purposes only and do not limit the scope of the present invention. In real time, various other server names based on the scenario can be used.

[0112] Figure 5The architecture of an edge computing system (1000) for enabling an edge application server (310) in a 3GPP network (200) according to an embodiment disclosed herein is shown. The architecture of the proposed edge computing system (1000) includes a UE (100), a 3GPP network (200), a centralized edge enabler server (620), and multiple edge data networks (300A, 300B). The edge application server (310A) and the edge enabler server (320A) of the edge data network (300A) communicate through the edge (3) (i.e., edge (3A)) of the edge data network (300A). The edge data network (300A) communicates with the UE (100) through application data traffic (500A). The edge data network (300A) communicates with the centralized edge enabler server (620) through a reference point referred to as edge (8A). The edge application server (310B) and edge enabler server (320B) of the edge data network (300B) communicate via edge (3) (i.e., edge (3B)) of the edge data network (300A). The edge data network (300A) communicates with the UE (100) via application data traffic (500B). The edge data network (300B) communicates with the centralized edge enabler server (620) via a reference point referred to as edge (8B). The centralized edge enabler server (620) communicates with the edge enabler client (120) of the UE (100) and the 3GPP network (200) via edge (1) and edge (2), respectively, where edge (1) and edge (2) are reference points.

[0113] The centralized edge enabler server (620) provides the support functions required by the edge application servers (310A, 310B). The edge (8A) and edge (8B) are reference points between the centralized edge enabler server (620) and the edge application servers (310A, 310B), wherein the edge (8A) and edge (8B) support interactions related to the edge enabler layer. The edge (8A) and edge (8B) allow the registration of availability information, such as time constraints, location constraints, etc., with the edge application servers (310A, 310B). In addition, the edge (8A) and edge (8B) allow the UE (100) to access network capability information, such as location information. The centralized edge enabler server (620) allows edge application servers (310A, 310B) to publish information about edge application servers (310A, 310B) from multiple edge data networks (300A, 300B) to provide profile / availability information of edge application servers (310A, 310B), such as available geographic areas of edge application servers (310A, 310B), operating hours of edge application servers (310A, 310B), etc.

[0114] The centralized edge enabler server (620) determines whether to relocate the application context of the UE (100) and provides relevant instructions to the source edge application server (310C). The source edge application server (310C) prepares the application context required for the relocated UE (100) and transmits the application context to the target edge application server (310D). When relocating the application context, the centralized edge enabler server (620) provides the IP address of the target edge application server (310D) to the UE (100).

[0115] The centralized edge enabler server (620) exposes a location reporting API to edge application servers (310A, 310B) on multiple edge data networks (300A, 300B) to support tracking or checking the effective location of the UE (100). The location reporting API exposed by the edge application servers (310A, 310B) relies on the SCEFN / NEF northbound API to monitor the event of the location of the UE (100).

[0116] The centralized edge enabler server (620) exposes a UE identifier API to the edge application servers (310A, 310B) to provide a valid UE identifier for the capability exposure API through the edge (8A) and edge (8B). The capability exposure API enables the edge application servers (310A, 310B) to anonymously point users through different service APIs exposed by the centralized edge enabler server (620).

[0117] The centralized edge enabler server (620) provides support functions required by the edge enabler client (120) located within the UE (100). The edge (1) supports interactions related to enabling edge computing between the centralized edge enabler server (620) and the edge enabler client (120). The edge (1) allows configuration information to be retrieved and provisioned for the UE (100). In addition, the edge (1) allows the discovery of edge application servers (310A, 310B) available in multiple edge data networks (300A, 300B).

[0118] A centralized edge enabler server (620) allows an edge enabler client (120) to discover edge application servers (310A, 310B) on multiple edge data networks (300A, 300B).

[0119] The centralized edge enabler server (620) allows subscriptions from edge enabler clients (120) to the centralized edge enabler server (620) for dynamic information, such as the dynamic availability of edge application servers (310A, 310B). In an embodiment, the subscription is highly specific to one of the edge application servers (310A, 310B). In another embodiment, the subscription generally includes all edge application servers (310A, 310B).

[0120] The centralized edge enabler server (620) provides the support functions required by the 3GPP network (200). The edge (2) is a reference point that allows edge enabler layer related interactions between the edge enabler servers (320A, 320B) and the 3GPP network (200). The edge (2) allows access to 3GPP network functions and APIs to retrieve network capability information.

[0121] In another embodiment, the centralized edge enabler server (620) may be deployed in a scenario where the distributed edge enabler server (320B) is not deployed within the edge data network (300A) and the centralized edge enabler server (620) supports the functions and reference points. In another embodiment, when the centralized edge enabler server (620) supports the functions and reference points, the centralized edge enabler server (620) may be deployed within the 3GPP network (200). In another embodiment, when the centralized edge enabler server (620) supports the functions and reference points, the centralized edge enabler server (620) may be deployed in another edge data network (300B).

[0122] Figure 6 The architecture of an edge computing system (1000) proposed for publishing and discovering service APIs (314A, 314B) of edge application servers (310A, 310B) by using CAPIF core functions (621) according to an embodiment disclosed herein is shown. The centralized edge enabler server (620) includes the CAPIF core functions (621). The PLMN trust domain (700) of the edge computing system (1000) includes edge application servers (310A, 310B), the centralized edge enabler server (620) and the PLMN edge application server (305B), wherein the edge application server (310B) and the PLMN edge application server (305B) are included in the edge data network (300B). The third-party edge application server (305A) and the edge application server (310A) are part of the edge data network (300A), and the third-party edge application server (305A) is not included in the PLMN trust domain (700).

[0123] The centralized edge enabler server (620) allows a third party or PLMN operator owned edge application server (305A, 305B) to access the service API (314A, 314B) provided by other edge application servers (310A, 310B) within and on the edge data network (300A, 300B) by providing CAPIF core functions (621). In an embodiment, the third party edge application server (305A) provides the service API and the third party edge application server (305A) exists outside the PLMN trust domain (700). Allowing the third party edge application server (305A) to utilize the CAPIF core functions (621) of the PLMN trust domain (700).

[0124] The centralized edge enabler server (620) provides the following functions for publishing and discovering the service APIs (314A, 314B) of the edge application servers (310A, 310B). The CAPIF core function (621) allows the loading (onboarding) of the edge application servers (310A, 310B) (i.e., API callers), publishing the service APIs (314A, 314B), discovering the service APIs (314A, 314B), and charging for the calls of the service APIs (314A, 314B).

[0125] The edge application server (310A, 310B) provides the following functions for publishing and discovering service APIs (314A, 314B). The API exposure function (311A) allows the call of the service API (314A) exposed from the edge application server (310A) via CAPIF (2e). The API exposure function (311B) allows the call of the service API (314B) exposed from the edge application server (310B) via CAPIF (2). In addition, the API exposure function (311A, 311B) allows the billing of the call of the service API (314A, 314B) via CAPIF (3). The API publishing function (312A, 312B) allows the publishing of the service API (314A, 314B) to the CAPIF core function (621) of the centralized edge enabler server (620) via CAPIF (4). The API management function (313A, 313B) allows the management of the service APIs (314A, 314B) to the CAPIF core function (621) via the CAPIF (5).

[0126] In addition, the following process is performed in accordance with the provisions in 3GPP TS23.222. The edge application server (310A, 310B) acts as an API exposure function (312A, 311B), and the edge application server (310A, 310B) publishes the service API (314A, 314B) to the CAPIF core function (621) of the centralized edge enabler server (620). The CAPIF core function (621) makes the service APIs (314A, 314B) of the edge data network (300A, 300B) available to each other. The edge application server (310A, 310B) acts as an API caller and is loaded onto the CAPIF core function (621). The edge application server (310A, 310B) (i.e., the API caller) uses the CAPIF core function (621) for authentication. The edge application server (310A, 310B) discovers the service API (314A, 314B) published by the edge application server (310A, 310B) via the CAPIF core function (621) by including the endpoint address of the API exposure function (311A, 311B). The service API call is performed based on the endpoint address. The edge application server (310A, 310B) obtains authorization to call the service API (314A, 314B) from the CAPIF core function (621). The edge application server (310A, 310B) calls the service API (314A, 314B) after performing authentication using the CAPIF core function (621).

[0127] Figure 7 is a timing diagram illustrating a method for managing application context relocation according to an embodiment disclosed herein. Consider an example scenario in which a UE (100) is playing an online video by receiving data of the online video from a first edge data network (i.e., a source edge data network) (300C). Later, while playing the online video, the UE (100) moves from a first geographic location and arrives at a second geographic location, where the second edge data network (target edge data network) (300D) is closer to the UE (100) than the first edge data network (300C). A centralized edge enabler server (620) supports application context relocation from a source edge data network (300C) to a target edge data network (300D), where the application context according to the example scenario is a location in the online video from which the UE (100) needs to switch to receiving data of the online video from the second edge data network (300D).

[0128] In step 701, in response to receiving a request from a UE (100), the source edge data network (300C) determines application context relocation. In step 702, the source edge data network (300C) sends a request for application context relocation to a centralized edge enabler server (620). In an embodiment, the request for application context relocation includes UE information, source application instance information, core network-network function information, application identifier, and edge enabler client registration context. In step 703, in response to receiving the request for application context relocation, the centralized edge enabler server (620) confirms to the source edge data network (300C).

[0129] At step 704A, the source edge data network (300C) transmits the application context to the centralized edge enabler server (620). At step 704B, the centralized edge enabler server (620) forwards the application context to the centralized edge application server 610. At step 705A, in response to receiving the application context, the centralized edge application server (610) confirms to the centralized edge enabler server (620). At step 705B, in response to receiving the confirmation from the centralized edge application server (610), the centralized edge enabler server (620) confirms to the source edge data network (300C). The centralized edge enabler server (620) temporarily saves the application context until the target edge data network (300D) is determined. At step 706, the centralized edge enabler server (620) determines information about the target edge data network (300D).

[0130] In step 707, the centralized edge enabler server (620) sends a request for application context relocation to the target edge data network (300D). In step 708, in response to receiving the request for application context relocation, the target edge data network (300D) confirms to the centralized edge enabler server (620). In step 709, the target edge data network (300D) sends an application context relocation response to the centralized edge enabler server (620). In an embodiment, the application context relocation response includes UE information, accepted Src application instance information and temporary edge application server information. In step 710, in response to receiving the application context relocation response, the centralized edge enabler server (620D) transmits the application context to the target edge data network (300D). In step 711, the centralized edge enabler server (620) sends an application context relocation response to the source edge data network (300C). At step 712, the source edge data network (300C) triggers an application function request to affect traffic routing.

[0131] Figure 8An overview of a system (1000) for handling PDU sessions during emergency services according to embodiments disclosed herein is shown.

[0132] For the case where the UE (100) has a PDU session for emergency services, the proposed method for managing the UE (100) and the network (not shown) is described as follows. The UE (100) sends a registration request message containing an NSSAI request to the AMF (800). The AMF server (800) processes the registration request message. The AMF server (800) initiates a network slice specific authentication and authorization process for the S-NSSAI present in the NSSAI request, which is subject to network slice specific authentication and authorization.

[0133] When network slice specific authentication and authorization fails for all S-NSSAIs in the allowed NSSAIs, and the UE (100) is establishing / has established a PDU session for emergency services, the AMF server (800) sends a NAS message (e.g., a configuration update command) with a list of rejected S-NSSAIs, and each of the list has an appropriate rejection cause value. In addition, the AMF server (800) keeps the emergency PDU session active and continues the emergency service. The network does not deregister the UE (100). In addition, when the PDU session for emergency services is released, the network deregisters the UE (100). For example, the AMF deactivates all non-emergency PDU sessions using NAS signaling or implicitly. In addition, the AMF server (800) indicates the implicit deactivation of all active PDU sessions to the UE (100) in a NAS message. In addition, the AMF server (800) sends the list of rejected NSSAIs to the UE (100) during the deregistration process (e.g., a deregistration request message).

[0134] When network slice specific authentication and authorization fails for all S-NSSAIs in the allowed NSSAIs, and the UE (100) does have a PDU session for emergency services, the AMF performs a network initiated deregistration procedure and includes a list of rejected S-NSSAIs, each with an appropriate rejection cause value, into an explicit deregistration request message. In response to receiving a deregistration request message with a rejection cause, which is relevant to a scenario such as a 5GMM cause value of #62 "No network slice available", when the UE (100) finds a suitable cell on an Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) cell, the UE (100) selects the E-UTRAN cell and initiates an attachment procedure to the EPS network. For example, when the UE (100) can access EPS services in the EPS network, the UE (100) redirects the UE (100) to the EPS network by including an appropriate cause (e.g., #31 "Redirection to Evolved Packet Core (EPC) required") in the deregistration request message. In another example, the UE (100) redirects the UE (100) to the EPS network by including an indicator requesting the UE (100) to select an E-UTRAN cell. Upon receiving the deregistration request with a rejection cause or indicator, the UE (100) performs at least one of the following actions:

[0135] 1) The UE (100) sets the fifth generation system (5GS) update status to the value "5U3 roaming not allowed" and stores the 5GS update status.

[0136] 2) The UE (100) deletes any 5G Globally Unique Temporary Identifier (5G-GUTI), the last visited registered Tracking Area Identity (TAI), the TAI list and the Key Set Identifier (ngKSI).

[0137] 3) The UE (100) resets the registration attempt counter and enters the state "5GMM-DEREGISTERED"

[0138] 4) If the E-UTRA capability is disabled, the UE (100) enables the E-UTRA capability.

[0139] 5) The UE (100) disables the N1 mode capability of 3GPP access.

[0140] 6) If the UE (100) operates in single registration mode, the UE processes EPS Mobility Management (EMM) parameters, EMM status, EPS update status, 4G Globally Unique Temporary Identifier (4G-GUTI), TAI list, key set identifier (eKSI) and attach attempt counter as specified in 3GPP TS 24.301 for the case where the EPS attach procedure is rejected (with an EMM cause corresponding to the value of 5GMM cause value #62 "No network slice available").

[0141] Fig. 9 8 is a block diagram of an AMF server (800) according to an embodiment disclosed herein. The AMF server (800) includes a processor (810), a memory (820), a communicator (830), and an emergency service-based PDU session controller (840). The processor (810) is provided together with the memory (820), the communicator (830), and the emergency service-based PDU session controller (840). Figure 2 The general operations of the processor (810), memory (820) and communicator (830) have been explained in .

[0142] The emergency service based PDU session controller (840) is configured to detect that the UE (100) has a PDU session for emergency services and the UE (100) is establishing one of the PDU sessions for emergency services. In addition, the emergency service based PDU session controller (840) is configured to detect that network slice authentication and authorization have failed for all allowed network slice selection identifiers (NSSAIs). In response to detecting that the UE (100) has a PDU session for emergency services and the UE (100) is establishing one of the PDU sessions for emergency services, and detecting that network slice authentication and authorization have failed for all allowed NSSAIs, the emergency service based PDU session controller (840) does not deregister the UE (100) and sends a configuration update command including a rejected NSSAI and a rejection cause value to the UE (100).

[0143] In addition, the emergency service based PDU session controller (840) is configured to determine that the PDU session for the emergency service is completed. In addition, the emergency service based PDU session controller (840) is configured to deregister the UE (100) in response to determining that the PDU session for the emergency service is completed. In addition, the emergency service based PDU session controller (840) is configured to send a deregistration request message with a rejection cause value to the UE (100).

[0144] The foregoing description of specific embodiments will fully reveal the general nature of the embodiments herein so that others can easily modify and / or adjust these specific embodiments for various applications by applying current knowledge without departing from the general concepts, and therefore, such adjustments and modifications should and are intended to be understood as being within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the words or terms used herein are for descriptive purposes and not for limitation. Therefore, although the embodiments herein have been described according to preferred embodiments, those skilled in the art will recognize that the embodiments herein can be modified to practice within the scope of the embodiments described herein.

Claims

1. A method performed by a centralized edge enabler server (EES) in an edge computing system, the method comprising: Load the edge application server EAS as an application programming interface API caller into the core function of the public API framework CAPIF; Authenticating the EAS using the CAPIF core functionality; discovering, via the CAPIF core function, at least one service API published by the EAS, and obtaining information including an endpoint address of an API exposed function; as well as The at least one service API is called based on the endpoint address of the API exposure function.

2. The method according to claim 1, wherein: The CAPIF core functionality provides the ability to discover service APIs published by the edge application server.

3. The method according to claim 1, wherein: The centralized EES provides the CAPIF core functionality to enable third-party edge application servers located outside the PLMN trust domain to access the at least one service API.

4. The method according to claim 1, wherein: The CAPIF core functionality allows for billing of service API calls.

5. The method according to claim 1, wherein: The calling of the at least one service API is performed based on information including an endpoint address of the API exposure function provided by the EAS.

6. The method according to claim 1, wherein: The CAPIF core functionality allows publication of service APIs provided by the EAS.

7. A centralized edge enabler server EES in an edge computing system, the centralized EES comprising: Transceiver; and A controller is coupled to the transceiver and is configured to: Load the edge application server EAS as an application programming interface API caller into the core function of the public API framework CAPIF, Authenticating the EAS using the CAPIF core functionality, discovering, via the CAPIF core function, at least one service API published by the EAS and obtaining information including an endpoint address of an API exposed function, and The at least one service API is called based on the endpoint address of the API exposure function.

8. The centralized EES according to claim 7, wherein: The CAPIF core functionality provides the ability to discover service APIs published by the edge application server.

9. The centralized EES according to claim 7, wherein: The centralized EES provides the CAPIF core functionality to enable third-party edge application servers located outside the PLMN trust domain to access the at least one service API.

10. The centralized EES according to claim 7, wherein: The CAPIF core functionality allows for billing of service API calls.

11. The centralized EES according to claim 7, wherein: The calling of the at least one service API is performed based on information including an endpoint address of the API exposure function provided by the EAS.

12. The centralized EES according to claim 7, wherein: The CAPIF core functionality allows publication of service APIs provided by the EAS.

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