Managing tracking areas in a wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. An user equipment (UE) receives, from a network entity, steering of roaming (SOR) information, performs a security check based on the SOR information, based on a successful security check, determines whether the SOR information includes SOR information for localized services, and based on the determination, removes a tracking area from a forbidden tracking area list.

Description

MANAGING TRACKING AREAS IN A WIRELESS COMMUNICATION SYSTEM

[0001] The disclosure pertains to a wireless communication system, and more particularly, to a method and system for managing tracking areas within a wireless communication system.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] In a first aspect of the disclosure, provided herein is method performed by an user equipment (UE) in a wireless communication system, the method comprising: receiving, from a network entity, steering of roaming (SOR) information; performing a security check based on the SOR information; based on a successful security check, determining whether the SOR information includes SOR information for localized services; and based on the determination, removing a tracking area from a forbidden tracking area list.

[0009] In a second aspect of the disclosure, provided herein is an user equipment (UE) in a wireless communication system, the UE comprising: at least one processor; and at least one memory, coupled to the at least one processor, storing instructions executable by the at least one processor to cause the UE to: receive, from a network entity, steering of roaming (SOR) information, perform a security check based on the SOR information, based on a successful security check, determine whether the SOR information includes SOR information for localized services, and based on the determination, remove a tracking area from a forbidden tracking area list.

[0010] These and other features, aspects, and advantages of the disclosure are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0011] FIG. 1 is a sequence diagram illustrating the handling of a Forbidden Tracking Area Identifier (FTAI) list according to an embodiment of the disclosure.

[0012] FIG. 2 is a block diagram of an user equipment (UE) that illustrates managing tracking areas in a wireless communication system according to an embodiment of the disclosure.

[0013] FIG. 3 is a flowchart that illustrates a method for managing tracking areas in a wireless communication system by the UE according to an embodiment of the disclosure.

[0014] FIG. 4 is a flowchart that illustrates a method for managing tracking areas in a wireless communication system by the UE according to an embodiment of the disclosure.

[0015] FIG. 5 is a sequence diagram that illustrates a scenario of handling the FTAI list according to an embodiment of the disclosure.

[0016] FIG. 6 is a sequence diagram that illustrates another example scenario of handling a forbidden tracking area (FTA) list based on network-provided information according to an embodiment of the disclosure.

[0017] FIG 7 is a sequence diagram illustrating another scenario of handling the FTAI list according to an embodiment of the disclosure.

[0018] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term "or" as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples are not be construed as limiting the scope of the embodiments herein.

[0019] As is traditional in the field, embodiments are described and illustrated in terms of blocks that carry out a described function or functions.　These blocks, which referred to herein as managers, units, modules, hardware components or the like, 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, hardwired circuits and the like, and optionally be driven by firmware and software. The circuits, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments be physically separated into two or more interacting and discrete blocks without departing from the scope of the proposed method. Likewise, the blocks of the embodiments be physically combined into more complex blocks without departing from the scope of the proposed method.

[0020] The accompanying drawings facilitate understanding of various technical features. The embodiments are not limited by these drawings and extend to any alterations, equivalents, and substitutes. Terms like first, second, etc., are used for distinction and do not limit the elements.

[0021] The Third Generation Partnership Project (3GPP) has introduced the concept of localized services to enhance user experiences by offering services limited to specific geographic areas and / or constrained by time. Localized services can be realized through various applications, such as live or on-demand audio / video streaming, electronic gaming, Internet Protocol Multimedia Subsystem (IMS), or through connectivity-based interactions like User Equipment (UE) to UE or UE to Data Network (DN). A service provider offering such services is referred to as a localized service provider, which may be an application provider or a network operator enabling localized delivery of services to end users through a hosting network.

[0022] In this context, a Credentials Holder (CH) may maintain a prioritized list of Standalone Non-Public Networks (SNPNs) and Group ID for Network Selection (GINs) for localized services in the SNPN, known as the CH_List. When a Mobile Station (MS) supports access to an SNPN providing localized services, the SNPN selection parameters for such access include:

[0023] a) A credentials holder-controlled prioritized list of preferred SNPNs for access to localized services in the SNPN, where each entry includes: i) An SNPN identity, ii) Validity information consisting of time validity information and optionally, iii) Location validity information and optionally location assistance information.

[0024] b) A credentials holder-controlled prioritized list of preferred GINs for access to localized services in the SNPN, where each entry includes: i) A GIN, ii) Validity information including time validity and optionally location validity, and iii) Optionally, location assistance information.

[0025] c) A combination of both the SNPN and GIN lists described above.

[0026] Despite the promising potential of localized services, several challenges and issues have emerged in their implementation and operation. The management of the CH_List can become complex, especially when dealing with multiple SNPNs and GINs, each with varying validity and location parameters. This complexity can lead to difficulties in ensuring seamless service delivery and maintaining an up-to-date and accurate CH_List.

[0027] Further, the dynamic nature of localized services, which are constrained by both geographic area and time, necessitates frequent updates and real-time management of the CH_List. This can strain network resources and increase the likelihood of errors or inconsistencies in service provision, potentially leading to user dissatisfaction.

[0028] Furthermore, the interoperability between different network operators and application providers offering localized services can be problematic. Ensuring that localized services are consistently and reliably delivered across different networks requires robust coordination and standardization, which may not always be present.

[0029] Furthermore, the privacy and security of users accessing localized services through SNPNs and GINs pose significant concerns. Protecting user data while enabling localized service access includes complex security protocols and mechanisms, which can be challenging to implement and manage effectively.

[0030] Thus, it is desired to address the above-mentioned disadvantages, issues, or other shortcomings or at least provide a useful alternative.

[0031] The principal object of the disclosure herein is to provide a method for managing tracking areas in a wireless communication system.

[0032] Yet another object of the disclosure is to enable the UE to receive and verify Steering of Roaming (SOR) information, including SNPN-specific data for localized services (SOR-SNPN-SI-LS), and to take appropriate action based on the verified information.

[0033] Yet another object of the disclosure is to facilitate the UE in identifying tracking areas associated with preferred SNPNs as defined in a credentials-holder-controlled prioritized list and to remove such tracking areas from a forbidden tracking area list when the associated validity conditions are met.

[0034] Yet another object of the disclosure is to enable the UE to detect changes in the validity status of SNPNs or GINs from not met to met and accordingly remove associated tracking areas which are part of the location validity information of the associated SNPNs or SINs, from forbidden tracking area lists for roaming and regional service provisioning.

[0035] Yet another object of the disclosure is to support time-based access control to the localized services by allowing the UE to compare the current time with time validity information associated with the preferred SNPNs or GINs and to dynamically update the tracking area restrictions for the tracking areas included in the location validity information of the associated SNPNs or GINs, based on the result.

[0036] In an aspect, the objectives are achieved by providing a method for managing tracking areas in the wireless communication system. Further, the method includes receiving by the UE the SOR information for localized services which is SOR-SNPN-SI-LS from a network apparatus. Further, the method includes performing by the UE a security verification on the received SOR-SNPN-SI-LS information. Further, the method includes identifying by the UE tracking areas included in location validity information corresponding to an SNPN in the SOR-SNPN-SI-LS information. In addition, the SNPN is identified by a credentials holder controlled prioritized list of preferred SNPNs for access for localized services in SNPN of the SOR-SNPN-SI-LS information. Further, the method includes deleting by the UE the tracking areas associated with the SNPN and the selected entry of the "list of subscriber data" or PLMN subscription identified from the forbidden Tracking Area lists.

[0037] According to an embodiment of the disclosure, the method includes deleting by the UE the tracking areas, which includes removing by the UE the tracking areas included in the location validity information corresponding to the SNPN identified by the credentials holder controlled prioritized list of preferred SNPNs for access for localized services in the SNPN, in the SOR-SNPN-SI-LS information.

[0038] According to an embodiment of the disclosure, the method includes deleting by the UE the tracking areas including removing by the UE tracking areas from forbidden tracking area lists associated with the SNPN and the selected entry of the "list of subscriber data" or Public Land Mobile Network (PLMN) subscription when the tracking areas are present in the forbidden tracking area lists.

[0039] According to an embodiment of the disclosure, the forbidden tracking area lists includes of at least one or both of "5GS forbidden tracking areas for roaming" or "5GS forbidden tracking areas for regional provision of service" or other forbidden tracking area list corresponding to any radio access technology.

[0040] In another aspect, the objectives are achieved by providing a method for managing tracking areas in a wireless communication system. The method includes determining by the UE that the UE supports access to the SNPN providing access for localized services in SNPN. Further, the method includes enabling by the UE access for localized services in the SNPN. Further, the method includes detecting by the UE that validity information of the SNPN identified by the credential holder's controlled prioritized list of preferred SNPNs for access for localized services in SNPN changes from not met to met. Further, the method includes detecting by the UE that validity information of any GIN (Group ID for Network Selection) identified by the credential's holder controlled prioritized list of preferred GINs for access for localized services in SNPN changes from not met to met.

[0041] Further, the method includes removing by the UE tracking areas included in location validity information of the SNPN from a list of 5GS forbidden tracking areas for roaming and the list of 5GS forbidden tracking areas for regional provision of service for the SNPN and for a selected entry of a list of subscriber data or Public Land Mobile Network (PLMN) subscription.

[0042] According to an embodiment of the disclosure, the method includes detecting by the UE that validity information of the SNPN identified by the credential holder's controlled prioritized list of preferred SNPNs for access for localized services in SNPN changes from not met to met. Further, the method includes monitoring by the UE validity information of the GIN broadcasted by the SNPN identified by the credentials holder controlled prioritized list of preferred GINs for access for localized services in SNPN changes from not met to met.

[0043] According to an embodiment of the disclosure, the method includes the validity information includes time validity information that matches with current time in the UE.

[0044] In another aspect, the objectives are achieved by providing the UE for managing tracking areas in a 5G system (5GS) for localized services in the SNPN. The UE includes a memory, a processor, and a tracking area controller coupled to the memory and the processor. Further, the network quality controller receives the SOR information from the network apparatus. Further, the network quality controller performs a security verification on the received SOR information. Further, it determines the SOR information comprises the SOR-SNPN-specific information for localized services (SOR-SNPN-SI-LS) upon successful verification. Further, the network quality controller identifies one or more tracking areas included in location validity information corresponding to the SNPN. The SNPN is identified by a credentials holder controlled prioritized list of preferred SNPNs for access to localized services. The network quality controller deletes the tracking areas identified by the SNPN and TAs listed in the credentials holder controlled prioritized list of preferred SNPNs for access for localized services in the SNPN from a forbidden TA list.

[0045] These and other aspects of the embodiments will be better understood with the following description and accompanying drawings. The descriptions, while indicating preferred embodiments and specific details, are for illustration and not limitation. Many changes and modifications can be made within the scope of the embodiments, which include all such modifications.

[0046] The existing systems for managing SNPN-based access for localized services often fail to dynamically update or manage the TA lists in response to changing validity information. In current systems, the UE (101) relies exclusively on a static configuration and lacks intelligent handling of temporary or geographically-bound SNPNs, leading to suboptimal access or service denial even when conditions are met. For example, even if the SNPN becomes valid for localized service access based on updated time or location, the UE (101) may not remove it from the forbidden list due to the absence of proactive checking or responsive handling.

[0047] According to an embodiment of the disclosure, the 5G Mobility Management (5GMM) sublayer states include, but are not limited to, the following: 5GMM-NULL, 5GMM-DEREGISTERED including sub-states 5GMM-DEREGISTEREDNORMAL-SERVICE, 5GMM-DEREGISTEREDLIMITED-SERVICE, 5GMM-DEREGISTEREDATTEMPTING-REGISTRATION, 5GMM-DEREGISTEREDPLMN-SEARCH, 5GMM-DEREGISTEREDNO-SUPI, 5GMM-DEREGISTEREDNO-CELL-AVAILABLE, 5GMM-DEREGISTEREDeCALL-INACTIVE, and 5GMM-DEREGISTEREDINITIAL-REGISTRATION-NEEDED. Additional states include 5GMM-REGISTERED-INITIATED, 5GMM-REGISTERED including sub-states 5GMM-REGISTEREDNORMAL-SERVICE, 5GMM-REGISTEREDNON-ALLOWED-SERVICE, 5GMM-REGISTEREDATTEMPTING-REGISTRATION-UPDATE, 5GMM-REGISTEREDLIMITED-SERVICE, 5GMM-REGISTEREDPLMN-SEARCH, 5GMM-REGISTEREDNO-CELL-AVAILABLE, and 5GMM-REGISTEREDUPDATE-NEEDED. Other states are 5GMM-DEREGISTERED-INITIATED and 5GMM-SERVICE-REQUEST-INITIATED.

[0048] According to an embodiment of the disclosure, the Evolved Mobility Management (EMM) sublayer states include, but are not limited to, the following: EMM-NULL, EMM-DEREGISTERED including sub-states EMM-DEREGISTEREDNORMAL-SERVICE, EMM-DEREGISTEREDLIMITED-SERVICE, EMM-DEREGISTEREDATTEMPTING-TO-ATTACH, EMM-DEREGISTEREDPLMN-SEARCH, EMM-DEREGISTEREDNO-IMSI, EMM-DEREGISTEREDATTACH-NEEDED, EMM-DEREGISTEREDNO-CELL-AVAILABLE, and EMM-DEREGISTEREDeCALL-INACTIVE. Additional states include EMM-REGISTERED-INITIATED, EMM-REGISTERED including sub-states EMM-REGISTEREDNORMAL-SERVICE, EMM-REGISTEREDATTEMPTING-TO-UPDATE, EMM-REGISTEREDLIMITED-SERVICE, EMM-REGISTEREDPLMN-SEARCH, EMM-REGISTEREDUPDATE-NEEDED, EMM-REGISTEREDNO-CELL-AVAILABLE, EMM-REGISTEREDATTEMPTING-TO-UPDATE-MM, and EMM-REGISTEREDIMSI-DETACH-INITIATED. Other states are EMM-DEREGISTERED-INITIATED, EMM-TRACKING-AREA-UPDATING-INITIATED, and EMM-SERVICE-REQUEST-INITIATED.

[0049] According to an embodiment of the disclosure, the Radio Access Technology (RAT) include, but is not limited to, NG-RAN cellular generations including 5G, 4G, 3G, and 2G core systems such as EPS and 5GS. Various forms of NR (New Radio) including NR in unlicensed bands, NR (LEO) satellite access, NR (MEO) satellite access, NR (GEO) satellite access, and NR (OTHERSAT) satellite access, NR Redcap, E-UTRA including E-UTRA in unlicensed bands, as well as NB-IoT, WB-IoT, and LTE-M are included.

[0050] According to an embodiment of the disclosure, the 5GS registration types include, but are not limited to, the following: initial registration, mobility registration updating, periodic registration updating, emergency registration, SNPN onboarding registration, disaster roaming initial registration, and disaster roaming mobility registration updating.

[0051] According to an embodiment of the disclosure, when the registration type is not set to disaster roaming initial registration or disaster roaming mobility registration updating, the 5GS registration type is considered to be set to one of the following: initial registration, mobility registration updating, periodic registration updating, emergency registration, or SNPN onboarding registration.

[0052] According to an embodiment of the disclosure, the PLMN selection as specified in 3GPP TS 23.122 may be performed without consideration of the Registered PLMN (RPLMN). In such a case, the mobile station (MS) selects and attempts registration on any available and allowable PLMN / access technology combinations in the following order: either the HPLMN (if the EHPLMN list is not present or is empty) or the highest priority EHPLMN that is available (if the EHPLMN list is present), each PLMN / access technology combination in the User Controlled PLMN Selector with Access Technology data file in the SIM in priority order, each PLMN / access technology combination in the Operator Controlled PLMN Selector with Access Technology data file in the SIM in priority order or stored in the mobile equipment (ME) in priority order, other PLMN / access technology combinations with a received high-quality signal in random order, and other PLMN / access technology combinations in order of decreasing signal quality.

[0053] According to an embodiment of the disclosure, the PLMN selection as specified in 3GPP TS 23.122 may be performed with consideration of the Registered PLMN (RPLMN). In such a case, the mobile station (MS) selects and attempts registration on any available and allowable PLMN / access technology combinations in the following order: either the RPLMN or the last registered PLMN, either the HPLMN (if the EHPLMN list is not present or is empty) or the highest priority EHPLMN that is available (if the EHPLMN list is present), each PLMN / access technology combination in the User Controlled PLMN Selector with Access Technology data file in the SIM in priority order, each PLMN / access technology combination in the Operator Controlled PLMN Selector with Access Technology data file in the SIM in priority order or stored in the mobile equipment (ME) in priority order, other PLMN / access technology combinations with a received high-quality signal in random order, and other PLMN / access technology combinations in order of decreasing signal quality.

[0054] According to an embodiment of the disclosure, a visited PLMN (VPLMN) is a PLMN different from the HPLMN (if the EHPLMN list is not present or is empty) or different from an EHPLMN (if the EHPLMN list is present).

[0055] An allowable PLMN, in the case of a Mobile Station (MS) operating in MS operation mode A or B, is a PLMN which is not in the list of "forbidden PLMNs" stored in the MS. In the case of an MS operating in MS operation mode C or an MS not supporting A / Gb mode and not supporting Iu mode, an allowable PLMN is a PLMN which is not in the list of "forbidden PLMNs" and not in the list of "forbidden PLMNs for General Packet Radio Service (GPRS) service" stored in the MS.

[0056] Further, an available PLMN is a PLMN(s) in the given area which is / are broadcasting capability to provide wireless communication services to the UE.

[0057] A Camped on a cell is a state in which the MS (or Mobile Equipment (ME) if there is no SIM) has completed the cell selection or reselection process and has selected a cell from which it intends to receive all available services. It is noted that the services may be limited and the PLMN or the Standalone Non-Public Network (SNPN) may not be aware of the existence of the MS (or ME) within the selected cell.

[0058] According to an embodiment of the disclosure, an EHPLMN is any of the PLMN entries included in the Equivalent HPLMN list.

[0059] Further, an Equivalent HPLMN list is to allow provision for multiple HPLMN codes. PLMN codes that are present within this list shall replace the HPLMN code derived from the IMSI for PLMN selection purposes. The list is stored on a Universal Subscriber Identification Module (USIM) and is known as the EHPLMN list. The EHPLMN list include the HPLMN code derived from the IMSI. If the HPLMN code derived from the IMSI is not present in the EHPLMN list, then it shall be treated as a Visited PLMN for PLMN selection purposes.

[0060] In addition, a Home PLMN is the PLMN where the MCC and MNC of the PLMN identity match the MCC and MNC of the IMSI.

[0061] Further, a Registered PLMN (RPLMN) is the PLMN on which certain LR (location registration which is also called as registration procedure) outcomes have occurred. In a shared network, the RPLMN is the PLMN defined by the PLMN identity of the CN operator that has accepted the LR.

[0062] According to an embodiment of the disclosure, a registration is the process of camping on a cell of the PLMN or the SNPN and doing any necessary LRs.

[0063] Further, an UPLMN is a PLMN / access technology combination in the "User Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order).

[0064] Further, an OPLMN is the PLMN / access technology combination in the "Operator Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order) or stored in the ME (in priority order).

[0065] The 5GS forbidden tracking areas for regional provision of service refers to the list of tracking areas in which the UE is prohibited from operating for normal services with the exception of emergency services. The MS adds the TA to this list upon receiving certain reject causes such as cause #12, #13, or #15.

[0066] When the UE (101) is not operating in SNPN access operation mode, the UE (101) maintains a list of 5GS forbidden tracking areas for roaming and a list of 5GS forbidden tracking areas for regional provision of service. However, when operating in SNPN access operation mode, the UE (101) stores these lists with the following granularity:

[0067] For 5GS forbidden tracking areas for roaming: per SNPN; and per entry of the "list of subscriber data", or, if the UE supports SNPN access using credentials from a credentials holder, then per equivalent SNPNs or per Public Land Mobile Network (PLMN) subscription.

[0068] For 5GS forbidden tracking areas for regional provision of service: per SNPN; and similarly, per entry of the "list of subscriber data", or per equivalent SNPNs or PLMN subscription, if the UE supports credential-based access.

[0069] According to an embodiment of the disclosure, the lists mentioned above are referred to as 5GS_forbidden_TA lists.

[0070] According to an embodiment of the disclosure, location validity information comprises one or more entries of location information. The validity information is considered to be met if the location validity information is unavailable and at least one time period of the time validity information coincides with the current time of the UE, or the location validity information is available, at least one time period of the time validity information coincides with the current time of the UE, and at least one location information entry matches the UE's current location.

[0071] The SNPN selected for localized services in SNPN refers to an SNPN that is selected by a Mobile Station (MS) supporting access to an SNPN providing localized services, provided such access is enabled. The selection of the SNPN may occur based on:

[0072] a) subclause 4.9.3.1.1 bullet a0);

[0073] b) subclause 4.9.3.2.1 bullet a0); or

[0074] c) manual selection by the user,

[0075] and where one of the following conditions is met:

[0076] i) the validity information of the SNPN is met;

[0077] ii) the validity information of Globally Unique Identifier(s) for Network (GIN(s)) broadcasted by the SNPN is met.

[0078] According to an embodiment of the disclosure, the SNPN selected for localized services in SNPN refers to the SNPN that is selected by the MS supporting access to the SNPN providing localized services, provided such access is enabled. The selection of the SNPN may occur based on:

[0079] a) subclause 4.9.3.1.1 bullet a0);

[0080] b) subclause 4.9.3.2.1 bullet a0); or

[0081] c) manual selection by the user, and where one of the following conditions is met:

[0082] i) the validity information of the SNPN is met;

[0083] ii) the validity information of Globally Unique Identifier(s) for Network (GIN(s)) broadcasted by the SNPN is met.

[0084] The SNPN access operation mode is the UE (101) operating in SNPN access operation mode only selects SNPNs. This includes the case when the UE (101) is accessing an SNPN over 3GPP access, the case when the UE (101) is accessing an SNPN over non-3GPP access, and the case where the UE (101) is accessing SNPN services via a PLMN.

[0085] Further, a 5GMM reject cause refers to certain Mobility Management (MM) rejection causes in the 5G system. When the UE (101) receives reject causes such as #12, #13, or #15 (not limited to these), it adds the corresponding TA to the 5GS_forbidden_TA lists. These rejection causes are hereafter referred to as Reject cause.

[0086] Further, the Steering of roaming SNPN selection information (SOR-SNPN-SI) refers to provisioning information used for SNPN selection. It includes:

[0087] a) a prioritized list of preferred SNPNs controlled by the credentials holder;

[0088] b) a prioritized list of preferred GINs controlled by the credentials holder; or

[0089] c) both lists.

[0090] FIG. 1 is a sequence diagram illustrating the handling of a Forbidden Tracking Area Identifier (FTAI) list according to an embodiment of the disclosure. The registration procedure is considered as an example in FIG. 1. In this context, the UE (101) supports access to the SNPN, providing access for localized services in the SNPN, and that access for localized services in the SNPN is enabled.

[0091] Further, FIG. 1 illustrates the involvement of a gNodeB (gNB) (102) and an Access and Mobility Management Function (AMF) (103) in the communication path. The gNB (102) is responsible for radio access and forwards relays signaling and data traffic towards the AMF (103). The AMF (103) manages key control-plane functionalities, including registration, connection, reachability, mobility, and access authorization within the 5G Core (5GC) network.

[0092] At step S1, the UE (101) attempts to access localized services and searches for the SNPN supporting localized services in the SNPN.

[0093] At step S2, the UE (101) is configured with information available in the CH-controlled prioritized list of the SNPNs and the GINs for localized services in the SNPN. The "Credentials Holder controlled prioritized list of preferred SNPNs for access for localized services in SNPN" includes:

[0094] i. SNPN-1;

[0095] ii. Time validity information indicating that access to localized services via SNPN-1 is permitted during the following time windows: 2:00 PM to 3:00 PM on the current day, 2:00 PM to 3:00 PM on the next day, and 3:00 PM to 4:00 PM on the day after that;

[0096] iii. location validity information indicating that Tracking Area Code (TAC)-1 of SNPN-1 is a valid area where localized services are provided.

[0097] At step S3, the UE (101) performs the SNPN selection for localized services in the SNPN as specified in clause 4.9.3.1.1 of 3GPP TS 23.122, assuming the current UE (101) time is 2:00 PM, which falls within the time validity window. At step S4, the UE (101) identifies that the TAC-1 of the SNPN-1 is currently available. At step S5, the UE (101) initiates a registration procedure or another NAS procedure with the network. At step S6, the UE (101) receives a registration reject message or equivalent NAS reject cause from the network. At step S7, the UE (101) adds SNPN-1 and TAC-1 to the 5GS_forbidden_TA list as per the defined behavior following a registration reject.

[0098] According to an embodiment of the disclosure, once the TA, such as (SNPN-1 TAC-1), is added to the 5GS_forbidden_TA list and in the absence of specific triggers such as a change, invalidation, or update of the entry in the list of subscriber data, removal of the USIM, or switch-off of the UE, the TA remains forbidden. Consequently, the TA continues to be restricted for localized services. In the example described above, the UE (101) may be unable to access the localized services during the time window of 2:00 PM to 3:00 PM on the next day or even during the period from 3:00 PM to 4:00 PM on the subsequent day, as Public Land Mobile Network (PLMN)-1 provides localized services only within TAC-1. The localized services are provided within limited geographic areas, such as specific TAs, and during defined time windows, either as one-time events or on a periodic basis.

[0099] To mitigate situations where the UE (101) is unable to access localized services within a designated time window or periodic interval due to the relevant TA, where a Standalone Non-Public Network (SNPN) provides such services being listed in the 5GS_forbidden_TA list, a mechanism is required for handling TAs present in the forbidden TA list of the UE (101). To address the aforementioned drawbacks, the invention discloses a combination of solutions that enable more dynamic and context-aware management of the 5GS_forbidden_TA list and introduce the dedicated list 5GS_FTAI_LS for access to localized services in the SNPN.

[0100] According to an embodiment of the disclosure, the term UE (101) and MS refer to the same entity. According to an embodiment of the disclosure, the MS may delete the list of 5GS_forbidden_TA lists or remove the TA from the 5GS_forbidden_TA lists associated with the SNPN when the UE (101) supports access to the SNPN providing access for localized services in SNPN and access for localized services in SNPN is enabled. Further, the validity information of the SNPN associated with the TA, as specified in the credentials holder controlled prioritized list of preferred SNPNs for access for localized services in SNPN, changes from not met to met or starts matching with the current time in the UE (101). Furthermore, the validity information of the global identifier of the network (GIN) broadcasted by the SNPN associated with the TA in the credentials holder controlled prioritized list of preferred GINs for access for localized services in SNPN changes from not met to met or starts matching with the current time in the UE (101).

[0101] Upon receiving steering of roaming (SOR) information and successfully completing the security check, the User Equipment (UE) (101) shall perform the following actions if the SOR information includes the SOR-SNPN-SI-LS:

[0102] 1. The UE (101) shall delete the Tracking Areas (TAs) identified by the SNPN(s) and / or the TA(s) in the credentials holder controlled prioritized list of preferred SNPNs for access to localized services in SNPN from the 5GS_forbidden_TA lists.

[0103] 2. The UE (101) shall delete the TAs identified by the Global Identification Numbers (GINs) broadcasted by the SNPN(s) and / or the TA(s) in the credentials holder controlled prioritized list of preferred GINs for access to localized services in SNPN from the 5GS_forbidden_TA lists.

[0104] 3. The UE (101) shall retain the knowledge that a TA is added to the 5GS_forbidden_TA lists for localized services. This retention occurs when the UE (101) supports access to the SNPN providing access for localized services in SNPN and such access is enabled.

[0105] According to an embodiment of the disclosure, the UE (101) maintains a separate and new list of 5GS_forbidden_TA lists (5GS_FTAI_LS) for localized services in SNPN. The MS may delete the list of 5GS_FTAI_LS or remove the TA from the list of 5GS_FTAI_LS associated with the SNPN when the UE (101) supports access to the SNPN providing access for localized services in the SNPN and such access is enabled.

[0106] The validity information of the SNPN associated with the TA in the credentials holder controlled prioritized list of preferred SNPNs for access for localized services in SNPN changes from not met to met or starts matching with the current time in the UE (101). Further, the validity information of the GIN (broadcasted by the SNPN) associated with the TA in the credentials holder controlled prioritized list of preferred GINs for access for localized services in SNPN changes from not met to met or starts matching with the current time in the UE (101).

[0107] Upon receiving the SOR information, the security check is successful, and the SOR includes the SOR-SNPN-SI-LS. The UE (101) shall delete the TAs identified by the SNPN(s) and / or the TA(s) in the credentials holder controlled prioritized list of preferred SNPNs for access to localized services in SNPN from the 5GS_FTAI_LS. Further, the UE (101) shall delete the TAs identified by the GIN(s) broadcasted by the SNPN(s) and / or the TA(s) in the credentials holder controlled prioritized list of preferred GINs for access to localized services in SNPN from the 5GS_FTAI_LS.

[0108] When the Mobile Station (MS) supports access to the Standalone Non-Public Network (SNPN) providing access for localized services in the SNPN, and access for localized services in the SNPN is enabled, the MS shall maintain one or more lists of 5GS_FTAI_LS, each associated with the SNPN. If the MS supports access to an SNPN using credentials from the credentials holder, equivalent SNPNs, or both, the MS shall maintain these lists per entry of the list of subscriber data or the Public Land Mobile Network (PLMN) subscription. The list of 5GS_FTAI_LS associated with the selected SNPN, and where applicable, with the selected entry of the list of subscriber data or PLMN subscription, shall be used by the MS.

[0109] Upon selection of a new SNPN, the MS shall retain the list of 5GS_FTAI_LS associated with the previously selected SNPN and its respective subscriber data or subscription entry. If the number of lists exceeds the storage capacity supported by the MS, the oldest stored list shall be deleted. Periodic deletion of all 5GS_FTAI_LS lists shall occur (e.g., in a period ranging from 12 to 24 hours) or upon power-off of the MS.

[0110] Further, the MS shall delete the list of 5GS forbidden tracking areas for roaming associated with an SNPN under the following conditions: 1) When the entry with the subscribed SNPN identifying the SNPN in the list of subscriber data is updated. 2) When the USIM is removed, provided the EAP-AKA' or 5G-AKA based primary authentication and key agreement was performed in the selected SNPN. 3) If the MS supports access to an SNPN using credentials from a credentials holder, equivalent SNPNs, or both, when the list of 5GS_FTAI_LS is associated with a list of subscriber data entry and that entry is updated, or when the PLMN subscription and USIM are removed.

[0111] An embodiment specifies that the number of 5GS_FTAI_LS lists supported by the MS is implementation-specific. When the MS supports access to the SNPN providing localized services, and such access is enabled, a message with cause value #15 (as defined in 3GPP TS 24.501) received by the MS operating in SNPN access mode over 3GPP access will trigger the addition of the TA to the list of 5GS_FTAI_LS associated with the selected SNPN. If applicable, this addition will apply to the selected entry of the list of subscriber data or PLMN subscription. Subsequently, the MS will search for a suitable cell within the same SNPN but belonging to a TA not included in the 5GS_FTAI_LS of the selected SNPN and corresponding subscriber data or subscription.

[0112] Furthermore, when the MS supports access to the SNPN providing localized services and such access is enabled, and the user selects an SNPN, the MS will initiate registration on this SNPN using the NG-RAN access technology. For this registration, the MS will ignore the contents of the 5GS_FTAI_LS.

[0113] According to an embodiment of the disclosure, the NAS of the MS or the MS itself will share the list of 5GS_FTAI_LS with the lower layers or access stratum. Generally, the conditions applied to the 5GS_forbidden_TA lists in the current art apply to 5GS_FTAI_LS as defined in 3GPP TS 24.501, TS 24.301, TS 23.122, and other specifications addressing 5GS_forbidden_TA lists. Exceptions or additions specific to 5GS_FTAI_LS are described in an embodiment of the disclosure.

[0114] FIG. 2 is a block diagram of the UE (101) illustrating the management of tracking areas in a wireless communication system according to an embodiment of the disclosure. Examples of the User Equipment (UE) (101) include, but are not limited to, Consumer Electronics (such as Mobile Phones and Smartphones), Tablets, Wearable Devices, Television, Computing Devices (such as Laptops, Notebooks, Desktops, Workstations, etc.), IoT Devices, Automotive Systems (such as connected cars, Autonomous Vehicles, Vehicle-to-Everything (V2X) communication devices, etc.), Enterprise Devices such as robotics, Specialized Equipment (such as Medical Devices, Public Safety Devices, etc.), and Media Devices (such as Gaming Consoles, Streaming Devices, etc.).

[0115] The wireless communication network system encompasses various types of networks, including but not limited to Cellular Networks (such as 2G, 3G, 4G, 5G, Beyond 5G (B5G) / 6G, or advanced cellular networks), Local Area Networks (LANs) (such as Wi-Fi, Li-Fi, etc.), Personal Area Networks (PANs) (such as Bluetooth, Zigbee, Z-Wave, etc.), Wide Area Networks (WANs) (such as Satellite Communication Networks, Long Range Wide Area Network, Narrowband IoT, Low-bandwidth communication for IoT, etc.), Metropolitan Area Networks (MANs), Machine-to-Machine (M2M), Ad Hoc and Mesh Networks, and Emerging and Advanced Networks.

[0116] The UE (101) comprises a processor (202), memory (204), an I / O interface (203), and a tracking area controller (205). The processor (202) of the UE (101) communicates with the memory (204), the I / O interface (203), and the tracking area controller (205). Configured to execute instructions stored in the memory (204), the processor (202) performs various processes. The processor (202) can include one or a plurality of processors and can be a general-purpose processor such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an Artificial Intelligence (AI) dedicated processor such as a neural processing unit (NPU).

[0117] Further, the memory (204) of the UE (101) includes storage locations addressable through the processor (202). The memory (204) is not limited to volatile memory and / or non-volatile memory and can include one or more computer-readable storage media. Non-volatile storage elements within the memory (204) can include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories.

[0118] The I / O interface (203) transmits information between the memory (204) and external peripheral devices. These peripheral devices are the input-output devices associated with the UE (101). The I / O interface (203) receives several pieces of information from the UE (101).

[0119] Operatively coupled to the memory (204) and the processor (202), the tracking area controller (205) facilitates data flow and coordination between components. This coupling enables the tracking area controller (205) to access and manage tracking area data in real-time. Implemented as an innovative integrated circuit within the network management apparatus, the tracking area controller (205) features a multi-core design in an embodiment of the disclosure, allowing for dynamic and context-aware management of tracking area information in the 5G communication system. The innovative integrated circuit for managing tracking areas combines analog and digital components to enhance performance and minimize power consumption. The analog components include a precision timing unit and a low-power signal detector to ensure reliable monitoring of time and location validity parameters. The digital components comprise a microcontroller unit (MCU) and a dedicated logic processor that collaboratively manage the 5GS_forbidden_TA lists and the 5GS_FTAI_LS, enabling timely updates and deletions based on context such as SOR reception, subscriber data changes, and SNPN validity evaluation.

[0120] The tracking area controller (205) receives the SOR information from a network apparatus. Security verification is performed on the received SOR information by the tracking area controller (205). This includes checking the integrity and authenticity of the SOR information using cryptographic techniques such as digital signatures and certificates. Upon successful verification, the tracking area controller (205) determines that the SOR information comprises the SOR-SNPN-specific information for localized services (SOR-SNPN-SI-LS). This specific information include details such as service types, quality of service parameters, and access control policies. One or more tracking areas included in location validity information corresponding to SNPN are identified by the tracking area controller (205). The SNPN is identified by the credentials holder controlled prioritized list of preferred SNPNs for access to localized services, which may be dynamically updated based on user preferences and network conditions.

[0121] Further, the tracking area controller (205) deletes one or more tracking areas included in the location validity information corresponding to the SNPN identified based on a credentials-holder-controlled prioritized list of preferred SNPNs for access to localized services in the SNPN. The tracking area controller (205) also facilitates deletion, by the UE, of tracking areas, which includes removing tracking areas from forbidden tracking area lists associated with the SNPN and the selected entry from a list of subscriber data or a Public Land Mobile Network (PLMN) subscription, when the tracking areas are present in the forbidden tracking area lists. The forbidden tracking area lists comprise at least one or both of: a list of 5GS forbidden tracking areas for roaming, and a list of 5GS forbidden tracking areas for regional provision of service.

[0122] The tracking area controller (205) deletes the tracking areas identified by the SNPN and TAs listed in the credentials holder controlled prioritized list of preferred SNPNs for access for localized services in the SNPN from a forbidden TA list. This deletion process includes updating internal databases and ensuring that the forbidden TA list is synchronized across all relevant network elements. Further, the tracking area controller (205) removes one or more tracking areas identified by GINs broadcasted by the SNPN. The GINs are included in the credentials holder controlled prioritized list of preferred GINs for access to localized services from at least one of the forbidden tracking area lists. This ensures that the UE (101) can seamlessly access localized services without encountering forbidden areas, thereby enhancing the user experience.

[0123] The tracking area controller (205) determines that the UE (101) supports access to the SNPN providing access for localized services in the SNPN. This determination includes checking the UE's capabilities, such as supported frequency bands, authentication methods, and service profiles. Access for localized services in the SNPN is enabled by the tracking area controller (205). The tracking area controller (205) detects that validity information of an SNPN identified by a credentials holder controlled prioritized list of preferred SNPNs for access for localized services in SNPN changes from not met to met. This change could be triggered by factors such as time-based policies, location updates, or network reconfigurations. Tracking areas included in location validity information of the SNPN are removed from a list of 5GS forbidden tracking areas for roaming and a list of 5GS forbidden tracking areas for regional provision of service for the SNPN and for a selected entry of a list of subscriber data or PLMN subscription by the tracking area controller (205). This ensures that the UE (101) can access the SNPN without restrictions, thereby improving service continuity and reliability.

[0124] The tracking area controller (205) monitors validity information of GIN broadcasted by the SNPN identified by the credentials holder controlled prioritized list of preferred GINs for access for localized services in the SNPN. This monitoring process includes continuously checking the broadcasted GINs against predefined criteria such as time windows, geographic boundaries, and service policies. This determination may be based on real-time data analytics and network status updates. Time validity information that matches with current time in the UE (101) is included in the validity information in the tracking area controller (205). This ensures that the UE (101) can access the SNPN services at the right time, enhancing the overall user experience.

[0125] In response to control by the UE (101), the tracking area controller (205) performs deletion of tracking areas by causing removal of one or more tracking areas corresponding to the GINs broadcasted by the SNPN. This deletion process includes sending control messages to network elements to update their tracking area lists. The GINs are part of the credentials holder controlled prioritized list of preferred GINs for localized service access from at least one forbidden tracking area list maintained by the UE (101). This ensures that the UE (101) can access localized services without encountering forbidden areas, thereby improving service availability and user satisfaction.

[0126] According to an embodiment of the disclosure, the tracking area controller (205) identifies that the UE (101) supports access to the SNPN configured to provide access for localized services. This identification process includes checking the UE's hardware and software capabilities, as well as its subscription details. Upon confirmation, the tracking area controller (205) enables access for localized services within the SNPN for the UE (101). The tracking area controller (205) continuously monitors the validity information associated with SNPNs listed in the credentials holder controlled prioritized list of preferred SNPNs. This monitoring process includes real-time data collection and analysis to ensure that the validity conditions are met. Upon detecting that the validity conditions such as time or location criteria of a particular SNPN transition from not met to met. Further the tracking area controller (205) detects validity information of any by a GIN (Group ID for Network Selection) (broadcasted by an SNPN) identified by a credentials holder controlled prioritized list of preferred GINs for access for localized services in SNPN changes from not met to met. Further, the tracking area controller (205) initiates removal of one or more tracking areas specified in the location validity information of the SNPN from the 5GS forbidden tracking area list for roaming, the 5GS forbidden tracking area list for regional provision of services, and from the relevant entries in the subscriber data or PLMN subscription records associated with the SNPN. This ensures that the UE (101) can access the SNPN services without restrictions, thereby enhancing service continuity and reliability.

[0127] The tracking area controller (205) monitors the validity information of the GIN broadcasted by the SNPN where the SNPN is identified based on a credentials holder controlled prioritized list of preferred GINs for access to localized services. This monitoring process includes continuously checking the broadcasted GINs against predefined criteria such as time windows, geographic boundaries, and service policies. Upon detecting that the validity information of the SNPN changes from a state of not met to met based on criteria such as time, location, or policy updates, the tracking area controller (205) determines that the SNPN is eligible to provide localized services and initiates necessary actions to restore access to the corresponding tracking areas. This includes updating internal databases, sending control messages to network elements, and ensuring that the UE (101) can seamlessly access the SNPN services.

[0128] FIG. 3 is a flowchart illustrating a method for managing tracking areas in a wireless communication system by the UE (101) according to an embodiment of the disclosure. At step 301, a security verification is performed on the SOR information received by the UE (101) from the network apparatus. At step 302, the UE (101) determines that the SOR information includes SOR-SNPN-specific information for localized services (SOR-SNPN-SI-LS) upon successful verification. The UE (101) checks for the presence of identifiers or flags indicating the availability of localized services. The extracted information is then stored in the UE's memory for further processing.

[0129] At step 303, tracking areas included in location validity information corresponding to the SNPN are identified. The SNPN is identified by a credentials holder controlled prioritized list of preferred SNPNs for access to localized services by the UE (101). The UE (101) cross-references the location validity information with the prioritized list to determine the relevant tracking areas. This step include accessing a database or a lookup table stored in the UE (101) to match the SNPN with its associated tracking areas.

[0130] At step 304, one or more tracking areas included in location validity information corresponding to the SNPN are identified again. The SNPN is identified by a credentials holder controlled prioritized list of preferred SNPNs for access to localized services by the UE (101). At step 305, deleting the tracking areas associated with the SNPN and the selected entry of the "list of subscriber data" or PLMN subscription from forbidden tracking area lists. In addition, the tracking areas identified by the SNPN and TAs listed in the credentials holder controlled prioritized list of preferred SNPNs for access to localized services in the SNPN are deleted from at least one forbidden tracking area list by the UE (101). The UE (101) ensures that these tracking areas are no longer restricted, allowing for seamless access to localized services. The deletion process includes modifying data structures or entries in the memory (204).

[0131] FIG. 4 is a flowchart illustrating a method for managing tracking areas in a wireless communication system by the UE (101) according to an embodiment of the disclosure. At step 401, the UE (101) determines that it supports access to the SNPN providing localized services by the Tracking Area Controller (205). At step 402, access for localized services in the SNPN is enabled by the Tracking Area Controller (205). The Tracking Area Controller (205) may send specific instructions or parameters to the UE (101) to enable this access. The UE (101) updates its settings accordingly to facilitate seamless connectivity.

[0132] At step 403, the Tracking Area Controller (205) detects that the validity information of the SNPN identified by a credentials holder controlled prioritized list of preferred SNPNs for localized services changes from not met to met. The UE (101) checks the validity information against the prioritized list to determine if the conditions for access are met. Upon detecting a change, the UE (101) updates its internal state to reflect the new status. At step 404, detecting that validity information by the UE (101), of any GIN (broadcasted by an SNPN) identified by a credential holder controlled prioritized list of preferred GINs for access for localized services in SNPN changes from not met to met.

[0133] At step 405, tracking areas included in the location validity information of the SNPN are deleted from at least one of a list of 5GS forbidden tracking areas for roaming and a list of 5GS forbidden tracking areas for regional provision of service for the SNPN and for a selected entry of a list of subscriber data or PLMN subscription. The UE (101) ensures that these tracking areas are no longer restricted, allowing for seamless access to localized services. The deletion process include modifying data structures or entries in the memory (204).

[0134] FIG. 5 is a sequence diagram illustrating a scenario of handling an FTAI list according to an embodiment of the disclosure. Consider a scenario where the UE (101) supports access to the SNPN offering localized services and such access is enabled.

[0135] At step S1, the UE (101) attempts to access localized services and searches for the SNPN supporting such services. This step involves scanning the available networks to identify the SNPN. Specific identifiers or parameters may be used by the UE (101) to filter and select the appropriate SNPN. The scanning process includes measuring signal strength, evaluating network capabilities, and verifying the presence of required service identifiers.

[0136] At step S2, the UE (101) is provisioned with information in a Credentials Holder (CH)-controlled prioritized list of SNPNs / GINs for localized services. This step involves receiving and storing the prioritized list in the UE's memory. The list includes details such as SNPN identifiers, time validity information, and location validity information. The UE (101) uses this information to manage access to localized services, including i) SNPN-1, ii) Time validity information (e.g., 2 PM to 3 PM of the day, 2 PM to 3 PM of the next day, 3 PM to 4 PM of the day later), iii) Location validity information indicating TAC-1 of SNPN-1 provides localized services.

[0137] At step S3, the UE (101) performs the SNPN selection for localized services in accordance with Section 4.9.3.1.1 of 3GPP TS 23.122, assuming the current time is 2 PM. This step involves selecting the appropriate SNPN based on the current time and the prioritized list. The UE (101) ensures that the selected SNPN meets the time and location validity criteria.

[0138] At step S4, the UE (101) detects TAC-1 of SNPN-1, which is broadcasted by the gNB (102). This step involves monitoring the broadcast signals from the gNB (102) to identify the tracking area code (TAC) of the SNPN. The UE (101) confirms that the detected TAC matches the one specified in the prioritized list. The detection process include decoding system information blocks (SIBs) and verifying the TAC against the stored list.

[0139] At step S5, the UE (101) initiates a Registration or NAS procedure with the AMF (103) through the gNB (102). This step involves sending a registration request to the Access and Mobility Management Function (AMF) (103) via the gNB (102). Relevant information such as the UE's identity and the selected SNPN is included in the request. The registration request include additional parameters such as security credentials, service preferences, and capability information.

[0140] At step S6, the UE (101) receives the reject cause from the network. This step involves receiving a rejection message from the network indicating that the registration attempt was unsuccessful. The rejection message includes a cause code specifying the reason for the rejection. The UE (101) may analyze the cause code to determine the appropriate action, such as retrying the registration or updating internal lists.

[0141] At step S7, in response to the rejection, the UE (101) adds the identified SNPN-1 and TAC-1 to the 5GS_forbidden_TA list maintained internally. This prevents further registration attempts within the same tracking area during the restricted period. The UE (101) updates its internal lists to mark the tracking area as forbidden, ensuring that it does not attempt to register in the same area again during the restricted period. The update process include setting timers and flags to manage the forbidden status.

[0142] At step S8, upon expiration of the configured time validity (e.g., at 3 PM the next day) and based on the CH list configuration, the UE (101) deletes the entry (SNPN-1, TAC-1) from the 5GS_forbidden_TA list. This step involves checking the current time against the validity information and removing the entry if the time window has expired.

[0143] At step S9, after the forbidden entry is deleted, the UE (101) may reinitiate a Registration Request toward SNPN-1 in TAC-1, thereby attempting access to localized services again. This step involves sending a new registration request to the network as the tracking area is no longer marked as forbidden. The UE (101) follows the standard registration procedure to gain access to the localized services. The reinitiation process include re-evaluating network conditions and updating internal states.

[0144] Further, once the TA (SNPN-1, TAC-1) is added to the 5GS_forbidden_TA list and in the absence of specific triggers such as a change, invalidation, or update to the list of subscriber data, removal of the USIM, or UE (101) switch-off, the TA remains marked as forbidden. Accordingly, the UE (101) may be unable to access localized services during future permitted windows, for example, between 2 PM and 3 PM the following day or between 3 PM and 4 PM the day after, since the localized service is exclusively available in TAC-1 of SNPN-1. This ensures that the UE (101) does not attempt to access restricted areas, thereby optimizing network resources and improving user experience. The forbidden status may be managed through periodic checks and updates based on network policies.

[0145] To mitigate this limitation, a solution is provided where the UE (101) removes the corresponding TA (SNPN-1, TAC-1) from the 5GS_forbidden_TA list at the onset of the valid time window (e.g., at 2 PM the next day). If the TA is again marked as forbidden due to another rejection event, the UE (101) is configured to repeat the removal action at the start of the next valid window (e.g., at 3 PM on the day after) based on the validity information in the CH list. This ensures that the UE (101) can access localized services during the permitted windows even if previous attempts were unsuccessful. The UE (101) continuously monitors the validity information and updates its internal lists accordingly to optimize access to localized services. The monitoring process include real-time checks and dynamic updates based on network feedback.

[0146] FIG. 6 is a sequence diagram illustrating another example scenario of handling a forbidden tracking area (FTA) list based on network-provided information according to an embodiment of the disclosure. As shown in FIG. 6, when the UE (101) supports access to SNPN that provides access for localized services in SNPN and access for such localized services is enabled, the following steps occur.

[0147] At step S1, the UE (101) attempts to obtain access to localized services by searching for a suitable SNPN that supports such services. This step involves scanning the available networks to identify the SNPN. The scanning process include evaluating signal strength, network capabilities, and service identifiers to select the appropriate SNPN.

[0148] At step S2, the UE (101) is configured with the CH-controlled prioritized list of SNPNs or the GINs for access to localized services in the SNPN. The list includes (i) SNPN-1, (ii) Time validity information including 2:00 PM to 3:00 PM on the current day, 2:00 PM to 3:00 PM on the next day, and 3:00 PM to 4:00 PM on the following day, and (iii) Location validity information indicating that TAC-1 of SNPN-1 provides localized services.

[0149] At step S3, the UE (101) performs the SNPN selection for the localized services in SNPN as per 4.9.3.1.1 of TS 23.122, assuming the current UE (101) time is 2:00 PM. This step involves selecting the appropriate SNPN based on the current time and the prioritized list.

[0150] At step S4, the UE (101) identifies TAC-1 of SNPN-1, for example, via system information broadcasted by the gNB (102). This step involves monitoring the broadcast signals from the gNB (102) to identify the tracking area code (TAC) of the SNPN. The detection process include decoding system information blocks (SIBs) and verifying the TAC against the stored list.

[0151] At step S5, the UE (101) triggers the registration procedure or other NAS procedure with the Access and the AMF (103). This step involves sending a registration request to the Access and Mobility Management Function (AMF) (103) via the gNB (102). Relevant information such as the UE's identity and the selected SNPN is included in the request. The registration request include additional parameters such as security credentials, service preferences, and capability information.

[0152] At step S6, the UE (101) receives the registration reject message, which includes the reject cause indicating that access to the SNPN at the TAC-1 is currently not allowed. This step involves receiving a rejection message from the network indicating that the registration attempt was unsuccessful. The rejection message includes a cause code specifying the reason for the rejection. The UE (101) may analyze the cause code to determine the appropriate action, such as retrying the registration or updating internal lists.

[0153] At step S7, based on the reject cause, the UE (101) adds (SNPN-1, TAC-1) to the 5GS_forbidden_TA list, which prevents further access attempts to the same SNPN at the same tracking area. This step involves updating the internal lists to mark the tracking area as forbidden, ensuring that the UE (101) does not attempt to register in the same area again during the restricted period. The update process include setting timers and flags to manage the forbidden status.

[0154] At step S8, the UE (101) receives SOR-SNPN-SI-LS information with (i) SNPN-1, (ii) Time validity information 2:00 PM to 3:00 PM of the day, 2:00 PM to 3:00 PM of the next day, and 3:00 PM to 4:00 PM of the day later, and (iii) Location validity information indicating TAC-1 of SNPN-1 provides localized services. This step involves receiving updated information from the network, which include changes to the validity information or new instructions for accessing localized services.

[0155] At step S9, based on the received SOR-SNPN-SI or SOR-SNPN-SI-LS information, the UE (101) deletes the entry (SNPN-1, TAC-1) from the 5GS_forbidden_TA list or clears the 5GS_forbidden_TA list entirely, thereby enabling consequent attempts to access localized services in SNPN-1 at TAC-1. This step involves updating the internal lists to remove the forbidden status, allowing the UE (101) to reattempt access to localized services.

[0156] Further, once the TA (SNPN-1, TAC-1) is added to the 5GS_forbidden_TA list without triggers such as change, invalidation, or update of the entry in the list of subscriber data, USIM removal, or switch-off of the UE, the TA will continue to be marked as forbidden and hence remain forbidden for localized services. In the example above, the UE (101) may be unable to access localized services from 2:00 PM to 3:00 PM the next day or even from 3:00 PM to 4:00 PM the day after since the SNPN-1 provides localized services only in TAC-1. This ensures that the UE (101) does not attempt to access restricted areas, thereby optimizing network resources and improving user experience. The forbidden status may be managed through periodic checks and updates based on network policies.

[0157] Therefore, as a solution, the UE (101) shall remove the TA from the 5GS_forbidden_TA list or delete the 5GS_forbidden_TA list upon receiving the SOR-SNPN-SI or SOR-SNPN-SI-LS information. This step involves updating the internal lists to remove the forbidden status, allowing the UE (101) to reattempt access to localized services.

[0158] FIG. 7 is a sequence diagram illustrating another scenario of handling the FTAI list according to an embodiment of the disclosure. When the UE (101) supports access to the SNPN providing localized services and access for localized services in the SNPN is enabled, the following steps occur. The sequence diagram outlines the steps taken by the UE (101) to manage access to localized services, ensuring handling of forbidden tracking areas based on time and location validity information.

[0159] At step S1, the UE (101) attempts to access localized services and searches for supporting localized services in the SNPN. This step involves scanning the available networks to identify the SNPN. The scanning process include evaluating signal strength, network capabilities, and service identifiers to select the appropriate SNPN.

[0160] At step S2, the UE (101) is configured with information in the Credentials Holder (CH)-controlled prioritized list of SNPNs / GINs for localized services in the SNPN. This list includes i) SNPN-1, ii) Time validity information (2 PM to 3 PM of the day, 2 PM to 3 PM of the next day, 3 PM to 4 PM of the following day), iii) Location validity information indicating that TAC-1 of SNPN-1 provides localized services.

[0161] At step S3, the UE (101) performs the SNPN selection for localized services in the SNPN as per Section 4.9.3.1.1 of TS 23.122, assuming the current UE time is 2 PM. This step involves selecting the appropriate SNPN based on the current time and the prioritized list.

[0162] At step S4, the UE (101) identifies TAC-1 of SNPN-1, for example, based on the broadcasted TAC from the gNB (102). This step involves monitoring the broadcast signals from the gNB (102) to identify the tracking area code (TAC) of the SNPN. The detection process includes decoding system information blocks (SIBs) and verifying the TAC against the stored list.

[0163] At step S5, the UE (101) triggers the registration procedure or another NAS procedure with the network. This step involves sending a registration request to the Access and Mobility Management Function (AMF) (103) via the gNB (102). Relevant information such as the UE's identity and the selected SNPN is included in the request. The registration request includes additional parameters such as security credentials, service preferences, and capability information.

[0164] At step S6, the UE (101) receives a reject cause from the network indicating unsuccessful registration or access. This step involves receiving a rejection message from the network indicating that the registration attempt was unsuccessful. The rejection message includes a cause code specifying the reason for the rejection. The UE (101) may analyze the cause code to determine the appropriate action, such as retrying the registration or updating internal lists.

[0165] At step S7, the UE (101) adds SNPN-1 and TAC-1 to the 5GS_FTAI_LS list. This step involves updating the internal lists to mark the tracking area as forbidden, ensuring that the UE (101) does not attempt to register in the same area again during the restricted period. The update process include setting timers and flags to manage the forbidden status.

[0166] The 5GS_FTAI_LS is a new list used to add forbidden TAs upon receiving a reject cause from the network when access to localized services in SNPN is enabled in the UE (101). Ideally, this new list inherits all properties of the existing 5GS_forbidden_TA list as defined in the prior art. Additionally, the new list follows further properties as described in an embodiment of the disclosure. The new list includes additional parameters such as time and location validity information, service quality requirements, and access restrictions.

[0167] According to an embodiment of the disclosure, the trigger for initiating SNPN selection by the UE (101) can be based on the time validity information associated with the given SNPN. For example, the UE (101) may determine that the current time falls within a predefined valid time window during which access to localized services through the SNPN is permitted.

[0168] According to an embodiment of the disclosure, the trigger can be based on Steering of Roaming (SOR) information such as the SOR-SNPN-SI-LS information received from the network. This information may direct the UE (101) to prioritize or select a particular SNPN for accessing localized services. The SOR information include additional parameters such as service quality requirements and access restrictions.

[0169] According to an embodiment of the disclosure, the disclosure enables the UE (101) to seamlessly access localized services in the SNPN environment, ensuring uninterrupted connectivity and service continuity even in dynamic conditions where time or network-triggered events affect SNPN availability. The seamless access may be achieved through real-time monitoring and dynamic updates based on network feedback.

[0170] According to an embodiment of the disclosure, the method further comprises: determining whether validity information changes from not met to met; and based on the determination, removing the tracking area associated with validity information of an SNPN from the forbidden tracking area list.

[0171] According to an embodiment of the disclosure, wherein the UE supports access to the SNPN for the localized services, and wherein an access for the localized services is enabled.

[0172] According to an embodiment of the disclosure, wherein the validity information comprises the validity information of SNPN identified by a prioritized list of SNPN for localized services.

[0173] According to an embodiment of the disclosure, wherein the validity information comprises validity information of Group ID for network selection (GIN) identified by a prioritized list of GIN for localized services, and wherein the GIN is broadcasted by the SNPN.

[0174] According to an embodiment of the disclosure, wherein the tracking area is associated with an SNPN identified by a prioritized list of SNPN for localized services.

[0175] According to an embodiment of the disclosure, wherein the forbidden tracking area list comprises a list of forbidden tracking area for roaming.

[0176] According to an embodiment of the disclosure, wherein the forbidden tracking area list comprises a list of forbidden tracking area for regional provision of service.

[0177] According to an embodiment of the disclosure, wherein the UE is further caused to: determine whether validity information changes from not met to met; and based on the determination, remove the tracking area associated with the validity information of an SNPN from the forbidden tracking area list.

[0178] The foregoing description of the specific embodiments will so fully reveal the general nature of an embodiment herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiment without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiment. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while an embodiment herein have been described in terms of preferred embodiment, those skilled in the art will recognize that an embodiment herein can be practiced with modification within the scope of an embodiment as described herein.

Claims

1.A method performed by an user equipment (UE) in a wireless communication system, the method comprising:receiving, from a network entity, steering of roaming (SOR) information;performing a security check based on the SOR information;based on a successful security check, determining whether the SOR information includes SOR information for localized services; andbased on the determination, removing a tracking area from a forbidden tracking area list.2.The method of claim 1, further comprising:determining whether validity information changes from not met to met; andbased on the determination, removing the tracking area associated with validity information of a Standalone Non-Public Network (SNPN) from the forbidden tracking area list.3.The method of claim 2,wherein the UE supports access to the SNPN for the localized services, andwherein an access for the localized services is enabled.4.The method of claim 2, wherein the validity information comprises the validity information of SNPN identified by a prioritized list of SNPN for localized services.5.The method of claim 2,wherein the validity information comprises validity information of Group ID for network selection (GIN) identified by a prioritized list of GIN for localized services, andwherein the GIN is broadcasted by the SNPN.6.The method of claim 1, wherein the tracking area is associated with an SNPN identified by a prioritized list of SNPN for localized services.7.The method of claim 1, wherein the forbidden tracking area list comprises a list of forbidden tracking area for roaming.8.The method of claim 1, wherein the forbidden tracking area list comprises a list of forbidden tracking area for regional provision of service.9.An user equipment (UE) in a wireless communication system, the UE comprising:at least one processor; andat least one memory, coupled to the at least one processor, storing instructions executable by the at least one processor to cause the UE to:receive, from a network entity, steering of roaming (SOR) information,perform a security check based on the SOR information,based on a successful security check, determine whether the SOR information includes SOR information for localized services, andbased on the determination, remove a tracking area from a forbidden tracking area list.10.The UE of claim 9, wherein the UE is further caused to:determine whether validity information changes from not met to met; andbased on the determination, remove the tracking area associated with validity information of a Standalone Non-Public Network (SNPN) from the forbidden tracking area list.11.The UE of claim 10,wherein the UE supports access to the SNPN for the localized services, andwherein an access for the localized services is enabled.12.The UE of claim 10, wherein the validity information comprises the validity information of the SNPN identified by a prioritized list of SNPN for localized services.13.The UE of claim 10,wherein the validity information comprises validity information of Group ID for network selection (GIN) identified by a prioritized list of GIN for localized services, andwherein the GIN is broadcasted by the SNPN.14.The UE of claim 9, wherein the tracking area is associated with an SNPN identified by a prioritized list of SNPN for localized services.15.The UE of claim 9, wherein the forbidden tracking area list comprises a list of forbidden tracking area for roaming, or a list of forbidden tracking area for regional provision of service.

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