System and method for optimizing user equipment selection of independent non-public networks

Abstract

Systems and methods for optimizing user equipment selection of independent non-public networks are disclosed. A method for optimizing selection of a User Equipment (UE) for an Independent Non-Public Network (SNPN) includes receiving SNPN selection parameters associated with a Public Land Mobile Network (PLMN) subscription list corresponding to one or more Global Subscriber Identity Modules (USIMs) from a PLMN or SNPN, where the SNPN selection parameters include the SNPN list and a plurality of configuration parameters for the one or more USIMs supported by the PLMN; and selecting at least one SNPN from the SNPN list based on the PLMN subscription list, and storing an SNPN selection parameter and a USIM associated with the SNPN selection parameter.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims priority from Indian provisional application No. 202341054251 filed in the Indian Intellectual Property Office on August 12, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to the field of Standalone Non-Public Networks (SNPNs), and more particularly, to systems and methods for optimizing selection of SNPNs by a User Equipment (UE). Background Art

[0004] Non-public networks (NPNs) are designed for non-public use and are intended for exclusive use by enterprises and other private entities. These networks can be configured in various ways, including as a standalone network, hosted by a public land mobile network (PLMN), or provided as a network slice of a PLMN. NPNs can be deployed as SNPNs that operate independently of PLMN network functions, or as public network integrated NPNs supported by PLMNs. SNPN devices are equipped with a "Subscriber Data List" that contains a subscriber identifier (Subscription Permanent Identifier or SUPI), an authentication certificate, an SNPN identity, and optionally an access identity and pre-configured rules. The aforementioned information allows users to register without relying heavily on a global subscriber identity module (USIM).

[0005] According to technical specifications such as the 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 23.122, the UE is configured with a "Subscriber Data List" which may include a network specific identifier or an International Mobile Subscriber Identity (IMSI) depending on the authentication process used. The Subscriber Data List facilitates the selection of the SNPN and may include a certificate for accessing the SNPN via a certificate holder. If the UE is equipped with a USIM with a PLMN subscription, the UE may be configured with SNPN selection parameters. The parameters include a priority list of user-controlled and certificate holder-controlled preferred SNPNs and a Group ID (GIN) for network selection. The Subscriber Data List may also contain time validity and location assistance information for local services.

[0006] In addition, as outlined in 3GPP TS24.501, specific protocols govern the handling of the UE when the UE is deemed to be illegal or encounters certain conditions. For example, the UE must delete or invalidate certain network data in specified circumstances, and if the UE does not support a certificate from a certificate holder, the UE considers certain SNPN entries invalid until the device is updated or restarted. Current specifications and documentation are insufficient to provide solutions for managing SNPN selection parameters, particularly in scenarios involving storing, deleting, and invalidating these parameters when selection data associated with PLMN subscriptions for various USIMs is received.

[0007] However, existing SNPN techniques do not adequately address the handling of permanent rejection reasons and the complexities caused by the inclusion of multiple entries with the same subscriber identifier in the subscriber data list. Summary of the invention

[0008] This summary is provided to introduce several aspects that are further described in the detailed description of the present disclosure in a simplified form. This summary is neither intended to identify key or essential aspects of the present disclosure nor to determine the scope of the present disclosure.

[0009] According to one aspect of the present disclosure, a method for optimizing a user equipment (UE) selection of a standalone non-public network (SNPN) includes: receiving, from a public land mobile network (PLMN) or SNPN, SNPN selection parameters associated with a PLMN subscription list corresponding to one or more global subscriber identity modules (USIMs), wherein the SNPN selection parameters include a SNPN list and a plurality of configuration parameters for the one or more USIMs supported by the PLMN; and selecting at least one SNPN from the SNPN list based on the PLMN subscription list, and storing the SNPN selection parameters and the USIM associated with the SNPN selection parameters.

[0010] According to one aspect of the present disclosure, a method for optimizing a user equipment (UE) selection of a standalone non-public network (SNPN) includes: selecting at least one SNPN from a SNPN list based on a PLMN subscription list and associated multiple SNPN selection parameters, wherein multiple SNPN selection parameters associated with the PLMN subscription list corresponding to one or more global subscriber identity modules (USIMs) are pre-configured at the UE, and wherein the multiple SNPN selection parameters include the SNPN list and multiple configuration parameters for the one or more USIMs supported by the PLMN.

[0011] According to one aspect of the present disclosure, a method for optimizing selection of a stand-alone non-public network (SNPN) by a user equipment (UE) includes selecting at least one SNPN from a subscriber data list, wherein the subscriber data list includes multiple entries corresponding to each of the one or more SNPNs, wherein each entry includes at least one of a subscription permanent identifier (SUPI), an authentication certificate, an SNPN ID, and a verification status indicator, and wherein the subscriber data list is pre-configured at the UE and the corresponding network entity.

[0012] According to one aspect of the present disclosure, a system for optimizing a user equipment (UE) selection of a standalone non-public network (SNPN) comprises: at least one memory; at least one processor operably connected to the at least one memory and configured to: receive SNPN selection parameters associated with a PLMN subscription list corresponding to one or more global subscriber identity modules (USIMs) from a public land mobile network (PLMN) or SNPN, wherein the SNPN selection parameters include a SNPN list and a plurality of configuration parameters for the one or more USIMs supported by the PLMN; and select at least one SNPN from the SNPN list based on the PLMN subscription list, and store the SNPN selection parameters and the USIM associated with the SNPN selection parameters.

[0013] According to one aspect of the present disclosure, a system for optimizing a user equipment (UE) selection of a stand-alone non-public network (SNPN) comprises: at least one memory; at least one processor operably connected to the at least one memory and configured to select at least one SNPN from the SNPN list based on a PLMN subscription list and associated multiple SNPN selection parameters, wherein the multiple SNPN selection parameters associated with the PLMN subscription list corresponding to one or more global subscriber identity modules (USIMs) are pre-configured at the UE, and wherein the multiple SNPN selection parameters include the SNPN list and multiple configuration parameters for the one or more USIMs supported by the PLMN.

[0014] According to one aspect of the present disclosure, a system for optimizing a user equipment (UE) selection of a stand-alone non-public network (SNPN) comprises: at least one memory; at least one processor operably connected to the at least one memory and configured to select at least one SNPN from a subscriber data list, wherein the subscriber data list comprises a plurality of entries corresponding to each of one or more SNPNs, wherein each entry comprises at least one of a subscription permanent identifier (SUPI), an authentication certificate, an SNPN ID, and a verification status indicator, and wherein the subscriber data list is pre-configured at the UE and the corresponding network entity.

[0015] At least some of the above and other features of the present invention are set forth in the claims.

[0016] In order to further illustrate the advantages and features of the present disclosure, a more specific description of the present disclosure will be presented by referring to the specific embodiments of the present disclosure shown in the accompanying drawings. These drawings only depict typical embodiments of the present disclosure and therefore should not be considered to limit its scope. Additional features and details will be used in the accompanying drawings to describe and explain the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0018] Figure 1 is an architecture showing access to PLMN services via SNPN using PLMN subscription according to the related art;

[0019] Figure 2A and Figure 2B A series of operations depicting a problem in a registration process for a UE when handling different PLMNs and SNPNs according to a conventional technique of the related art are shown;

[0020] Figure 3 A series of operations depicting a problem in a registration process for a UE when handling different PLMNs and SNPNs according to another conventional technique of the related art are shown;

[0021] Figure 4 A series of operations depicting a problem in a registration process for a UE when handling different PLMNs and SNPNs according to yet another conventional technique of the related art are shown;

[0022] Figure 5 A series of operations depicting a problem in a registration procedure for a UE when handling different PLMNs and SNPNs according to yet another conventional technique in the related art are shown.

[0023] Fig. 6A and Figure 6B A series of operations depicting a successful registration process for a UE when handling different PLMNs and SNPNs according to an embodiment of the present disclosure are shown;

[0024] Fig. 7A and Figure 7B A series of operations depicting a successful registration process for a UE when handling different PLMNs and SNPNs according to another embodiment of the present disclosure is shown;

[0025] Fig. 8A and Figure 8BA series of operations depicting a successful registration process for a UE when handling different PLMNs and SNPNs according to another embodiment of the present disclosure is shown;

[0026] Fig.9A and Fig. 9B A series of operations depicting a successful registration process for a UE when handling different PLMNs and SNPNs according to another embodiment of the present disclosure is shown;

[0027] Fig.10 A series of operations depicting a successful registration process for a UE when handling different PLMNs and SNPNs according to another embodiment of the present disclosure is shown;

[0028] Fig.11 A flow chart of a method for optimizing UE selection of SNPN according to an embodiment of the present disclosure is shown;

[0029] Fig.12 A flowchart of a method for optimizing UE selection of SNPN according to another embodiment of the present disclosure is shown;

[0030] Fig.13 A flowchart showing a method for optimizing UE selection of SNPN according to another embodiment of the present disclosure; and

[0031] Fig.14 An embodiment of a system according to an embodiment of the present disclosure is shown.

[0032] In addition, those skilled in the art will appreciate that the elements in the drawings are shown for simplicity and may not necessarily be drawn to scale. For example, a flow chart illustrates the most important steps involved in the method to help improve understanding of various aspects of the present disclosure. In addition, with respect to the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may only show those specific details relevant to understanding the embodiments of the present disclosure so as not to obscure the drawings with details that would be readily apparent to one of ordinary skill in the art having the benefit of the description herein. DETAILED DESCRIPTION

[0033] For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to various embodiments and specific language will be used to describe these embodiments. It is therefore not intended to limit the scope of the present disclosure, and changes and further modifications in the illustrated systems and further applications of the principles of the present disclosure illustrated therein are considered to be within the ordinary scope of those skilled in the art to which the present disclosure relates.

[0034] The terms used in the present disclosure are provided only for describing specific embodiments and are not intended to limit the scope of other embodiments. Unless the context clearly stipulates otherwise, the singular form includes plural indicators. The terms and words used herein, including technical or scientific terms, may have the same meaning as those generally understood by those skilled in the art. Terms usually defined in dictionaries may be interpreted as having the same or similar meaning as the contextual meaning of the relevant art or the same or similar meaning as the contextual meaning of the relevant art. Unless otherwise defined, terms should not be interpreted as ideal or overly formal meanings. Even if a term is defined in the present disclosure, the term should not be interpreted as excluding embodiments of the present disclosure in certain cases.

[0035] Those skilled in the art will understand that both the foregoing general description and the following detailed description are illustrative of the present disclosure and are not intended to be limiting.

[0036] Regardless of whether a feature or element is limited to only one use, it can still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element”. In addition, the use of the term “one or more” or “at least one” feature or element does not exclude the absence of the feature or element, unless otherwise specified by limiting language, including but not limited to “requires one or more…” or “requires one or more elements”.

[0037] Reference is made herein to some "embodiments". An embodiment is an example of a possible implementation of any feature and / or element of the present disclosure. Some embodiments have been described for the purpose of explaining one or more possible ways that a particular feature and / or element of the proposed disclosure satisfies the requirements of uniqueness, utility, and non-obviousness.

[0038] The use of phrases and / or terms including, but not limited to, "a first embodiment," "another embodiment," "an alternative embodiment," "an embodiment," "an embodiment," "an embodiment," "multiple embodiments," "some embodiments," "other embodiments," "another embodiment," "further embodiments," "additional embodiments," or other variations thereof, do not necessarily refer to the same embodiment. Unless otherwise stated, one or more specific features and / or elements described in conjunction with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may not be found in an embodiment. Although one or more features and / or elements may be described herein only in the context of a single embodiment, or in the context of more than one embodiment, or in the context of all embodiments, the features and / or elements may alternatively be provided separately or in any appropriate combination or not provided at all. Conversely, any features and / or elements described in the context of a separate embodiment may alternatively be implemented as existing together in the context of a single embodiment.

[0039] Any and all details set forth herein are used in the context of some embodiments and therefore should not be construed as limiting factors of the disclosure presented.

[0040] The terms "include", "comprises" or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process or method that includes a series of steps includes not only those steps but may also include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or subsystems or elements or structures or components following "includes..." do not exclude the presence of other devices or other subsystems or other elements or other structures or other components or additional devices or additional subsystems or additional elements or additional structures or additional components, without more constraints.

[0041] The term "coupling" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not these elements are in physical contact with each other. The terms "send", "receive" and "communication" and their derivatives cover both direct and indirect communication. The terms "include" and "comprise" and their derivatives refer to including but not limited to. The term "or" is an inclusive term meaning "and / or". The phrase "associated with..." and its derivatives refer to including, being included in, interconnected with, including, being included in, connected to or connected with, coupled to or coupled with, can communicate with, collaborate with, interlace, juxtapose, be close to, be bound to or bound with, have, have the nature of, have and or with, etc. The term "controller" refers to any device, system or part thereof that controls at least one operation. The function associated with any particular controller can be centralized or distributed, can be local or remote. When used with a list of items, the phrase "at least one of..." means that different combinations of one or more of the listed items can be used, and only one item in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C, and any variations thereof. As additional examples, the expression "at least one of a, b, or c" may refer to only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. Similarly, the term "set" refers to one or more items. Thus, a set of items may be a single item or a set of two or more items.

[0042] In addition, the multiple functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and implemented in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or a part thereof suitable for being implemented in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disc (CD), a digital video disc (DVD) or any other type of memory. "Non-transitory" computer-readable media does not include wired, wireless, optical or other communication links that transmit temporary electrical signals or other signals. Non-transitory computer-readable media include media that can permanently store data and media that can store data and rewrite it later, such as rewritable optical discs or erasable memory devices.

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0044] Figure 1 1 is an architecture 100 illustrating accessing PLMN services via SNPN using PLMN subscription according to the related art.

[0045] The architecture 100 includes a user equipment (UE) 102, a radio access network (RAN) 104, a service independent non-public network (SNPN) 106, and various data networks 108a, 108b, and 108c. The architecture 100 also includes a home public land mobile network (HPLMN) 112 and a non-3GPP interworking function (N3IWF) 113 associated with the HPLMN 112, which are connected to external data networks and servers (such as news, games, etc.) server 110 and server 114, respectively.

[0046] In an embodiment, a UE 102 equipped with a PLMN certificate and a SNPN certificate is connected to a RAN 104, which in turn interfaces with a serving SNPN 106. The RAN 104 may be configured to provide a wireless connection to the UE 102. The RAN 104 includes base stations and other infrastructure that facilitate communication between the UE 102 and the core network. The RAN 104 may be configured to handle tasks such as signal processing, radio resource management, and mobility management to ensure efficient and reliable communication. In addition, the serving SNPN 106 includes a user plane function (UPF) 107 and other 5G network functions (NFs). The architecture 100 allows the UE 102 to access various local data networks and remote data networks, such as a local edge data network 108a and a wider data network 108b.

[0047] The UPF 107 plays a vital role in managing and routing user data traffic between the UE 102 and various data networks. The UPF 107 can be configured to handle data forwarding and packet routing functions, ensuring that data packets are efficiently and accurately transmitted on the network. The UPF 107 acts as a gateway, interfacing with the RAN 104 and external data networks (such as local edge data networks and broader Internet services). The UPF 107 is responsible for Quality of Service (QoS) enforcement, traffic management, and policy application, which are essential to maintaining service quality and performance.

[0048] In another embodiment of the architecture, the N3IWF 113 within the HPLMN 112 facilitates connections to non-3GPP networks, acting as a bridge for secure communications between the 5G core network and external networks. The HPLMN 112 ensures that the UE 102 can access services provided by remote servers via the overlay network, including services for news and games.

[0049] Figure 2A and Figure 2B A series of operations 200 are shown that depict issues in the registration process for a UE 102 when dealing with different PLMNs and SNPNs, in accordance with conventional techniques of the related art.

[0050] In the above scenario, a series of operations correspond to communications between UE 102 and various network entities, including access and mobility management functions (AMFs) associated with different PLMNs and SNPNs.

[0051] At operation 201, UE 102 is inserted with SIM1, and the home PLMN (HPLMN) associated with SIM1 is PLMN1 202. Subsequently, at operation 203, UE 102 may initiate a registration process with the network using SIM1, wherein UE 102 communicates with an access and mobility management function (AMF) of PLMN1 202 to complete the registration process.

[0052] At operation 205, AMF / PLMN1 202 may send a downlink non-access stratum (DL NAS) message to UE 102 to share the PLMN subscription information. Upon receiving the DL NAS message, UE 102 may store the PLMN subscription information in its non-volatile memory. The information may include a certificate holder list containing details about SNPN-1, SNPN-2, and a group ID (GIN) for network selection tagged as ID1, as shown in operation 207.

[0053] At operation 209, SIM1 is removed, prompting UE 102 to send a deregistration request to the AMF of PLMN1 202. Furthermore, at operation 211, SIM1 is deregistered and the connection is effectively closed.

[0054] At operation 213, UE 102 may be inserted into SIM2, where the HPLMN of SIM2 is PLMN2. Due to mobility, at operation 215, UE 102 moves out of the coverage area of ​​PLMN1 202 and enters an area covered by PLMN3 204, SNPN1 206, and SNPN2 208.

[0055] At operation 217, a serious error occurs where the UE 102 incorrectly assumes that SNPN1 206 can provide service for PLMN2 and selects SNPN1 206 for registration. Therefore, at operation 219, the UE 102 incorrectly uses the PLMN subscription certificate for SNPN1 206 in the case of SIM2.

[0056] In operation 221, UE 102 sends a registration request to the AMF of SNPN1 206, which results in a registration rejection message (#75) due to an incorrect certificate, as shown in operation 223. Then, UE 102 attempts to register with SNPN2 208 in operation 225, and in operation 227, UE 102 sends a registration request to SNPN2 208. In operation 229, UE 102 attempts to register with SNPN2 again, but UE 102 fails to register and results in a rejection message (#75).

[0057] The above series of operations shows an erroneous registration attempt, illustrating a serious problem in managing multiple PLMN and SNPN subscriptions within a UE, resulting in repeated registration failures.

[0058] Figure 3 A series of operations 300 depicting issues in the registration process for a UE 102 when dealing with different PLMNs and SNPNs according to another conventional technique in the related art is shown.

[0059] At operation 301, UE 102 is inserted with SIM1 by the user, where the home public land mobile network (HPLMN) is PLMN1 202. The insertion of SIM1 triggers the initial network registration process. Subsequently, at operation 303, UE 102 registers with the network using SIM1. During registration, UE 102 communicates with the AMF associated with PLMN1 202 and successfully completes the registration process.

[0060] After registration, at operation 305, the AMF of PLMN1 202 sends a DL NAS message to UE 102. The DL NAS message is used to share PLMN subscription information. At operation 307, UE 102 stores the PLMN subscription information in non-volatile memory, ensuring that the data is retained even if the device is powered off. The stored information includes a certificate holder list, which includes SNPN1 206, SNPN2 208, and a GIN tagged as ID1.

[0061] In addition, UE 102 moves out of the coverage area of ​​PLMN1 202 due to mobility and enters the coverage area of ​​PLMN3 204, SNPN1 206, and SNPN2 208, as shown in operation 309. At operation 311, UE 102 initiates a registration request to SNPN1 206 to establish communication. At operation 313, UE 102 receives a registration rejection with rejection reason #3 from SNPN1 206. Rejection reason #3 may be sent to the UE because the UE fails the authentication check or because the identity of the UE is not accepted by the network. At operation 315, UE 102 marks SIM1 as invalid for SNPN1 206. At operation 317, UE 102 reselects SNPN2 208 and attempts to register with SNPN2 208.

[0062] At operation 319, UE 102 initiates a registration request to SNPN2 208 to establish communication with SNPN2 208. At operation 321, UE 102 receives a registration rejection with rejection cause #3. At operation 323, UE 102 marks SIM1 as invalid for SNPN2.

[0063] Figure 4 A series of operations 400 depicting issues in the registration process for the UE 102 when dealing with different PLMNs and SNPNs according to yet another conventional technique in the related art is shown.

[0064] At operation 401, UE 102 is inserted with SIM1 by the user, and the home public land mobile network (HPLMN) is PLMN1 202. The insertion triggers the initial network registration process. Subsequently, at operation 403, UE 102 registers with the network using SIM1. During registration, UE 102 communicates with the AMF associated with PLMN1 202 and successfully completes the registration process.

[0065] After registration, at operation 405, the AMF of PLMN1 202 sends a DL NAS message to UE 102. The DL NAS message is used to share PLMN subscription information. At operation 407, UE 102 stores the PLMN subscription information in non-volatile memory, ensuring that the data is retained even if the device is powered off. The stored information includes a certificate holder list, which includes SNPN1 206, SNPN2 208, and a GIN tagged as ID1.

[0066] In addition, UE 102 moves out of the coverage area of ​​PLMN1 due to mobility, and UE 102 enters the coverage area of ​​SNPN1 206, as shown in operation 409. At operation 411, UE 102 initiates a registration request to SNPN1 206. However, at operation 413, SNPN1 206 rejects the registration request with 5GMM cause #3.

[0067] After the registration rejection, at operation 415, UE 102 marks SIM1 as invalid for SNPN1 206. At operation 417, UE 102 reselects to SNPN2 208 and attempts to register. However, as shown in operation 419, UE 102 requests SNPN2 to register, and at operation 421, SNPN2 208 also rejects the registration request with the same 5GMM reason #3.

[0068] At operation 423, UE 202 marks SIM1 as invalid for SNPN2 208, indicating that UE 102 cannot register with SNPN1 206 or SNPN2 208 because the SIM1 certificate is not valid for these networks, as depicted in the series of rejections and status updates.

[0069] Figure 5 A series of operations 500 depicting issues in the registration process for a UE 102 when dealing with different PLMNs and SNPNs according to another conventional technique in the related art is shown.

[0070] At operation 501, UE 102 is inserted with two sets of certificates for SNPN1: Entry 1 (SNPN1 / SUPI1 / TLS1) and Entry 2 (SNPN1 / SUPI2 / TLS2). An initial registration process is triggered. TLS1 and TLS2 may represent different Transport Layer Security (TLS) types / protocols.

[0071] At operation 503, UE 102 selects the certificate of entry 1 for registration. After the above operations, at operation 505, UE 102 sends a registration request to SNPN1 206 using SUPI1.

[0072] At operation 507, SNPN1 206 rejects the registration request with 5GMM cause #3. As a result of the rejection, at operation 509, UE 102 marks SNPN1 206 as invalid for both entry 1 and entry 2. The rejection indicates that UE 102 cannot register with SNPN1 206 using the provided credentials for entry 2.

[0073] Fig. 6A and Figure 6B A series of operations 600 depicting a successful registration process for a UE 102 when handling different PLMNs and SNPNs in accordance with an embodiment of the present disclosure is shown.

[0074] At operation 601, UE 102 is inserted with SIM1 by a user, and the home public land mobile network (HPLMN) is PLMN1 202. The insertion of SIM1 triggers an initial network registration process.

[0075] At operation 603, UE 102 registers with the network using SIM1. During registration, UE 102 communicates with the AMF associated with PLMN1 202 and successfully completes the registration process.

[0076] At operation 605, the AMF of PLMN1 202 sends a DL NAS message to the UE 102. The DL NAS message serves as a confirmation of successful registration.

[0077] At operation 607, UE 102 stores the PLMN subscription information along with other 5GMM parameters in non-volatile memory, ensuring that the data is retained even if the device is powered off. The stored information includes a certificate holder list including SNPN1, SNPN2, and a GIN tagged as ID1. The stored information may also include the SUPI of SIM1.

[0078] For example, UE 102 stores SNPN selection parameters associated with PLMN subscription (as described in 3GPP TS 23.122) and other 5GMM parameters stored with the SUPI of the USIM in non-volatile memory. For example, the PLMN subscription information may include SNPN selection parameters associated with the PLMN subscription.

[0079] At operation 609 , SIM1 is removed, prompting UE 102 to send a deregistration request to the AMF of PLMN1 202 .

[0080] At operation 611 SIM1 is deregistered and the connection is effectively closed.

[0081] At operation 613, UE 102 is inserted into SIM2, wherein the HPLMN of SIM2 is PLMN2.

[0082] At operation 615, UE 102 deletes the PLMN subscription based on detecting a different SUPI for SIM2. For example, UE 102 deletes the SNPN selection parameters - PLMN subscription parameters stored for SIM1.

[0083] At operation 617 , the UE 102 moves out of the coverage area of ​​PLMN1 202 and enters an area covered by PLMN3 204 , SNPN1 206 , and SNPN2 208 .

[0084] At operation 619, the UE 102 selects the PLMN3 204 that provides a roaming service for the newly inserted SIM2.

[0085] At operation 621 , UE 102 initiates a registration request to PLMN3 204 .

[0086] At operation 623, UE 102 receives confirmation from PLMN3 204 that the registration is accepted and thus the connection is established.

[0087] Fig. 7A and Figure 7B A series of operations 700 depicting a successful registration process for a UE 102 when handling different PLMNs and SNPNs in accordance with another embodiment of the present disclosure is shown.

[0088] At operation 701, UE 102 is inserted with SIM1 by a user, and the home public land mobile network (HPLMN) is PLMN1 202. The insertion of SIM1 triggers an initial network registration process.

[0089] At operation 703, UE 102 registers with the network using SIM1. During registration, UE 102 communicates with the AMF associated with PLMN1 202 and successfully completes the registration process.

[0090] At operation 705, the AMF of PLMN1 202 sends a DL NAS message to the UE 102. The DL NAS message is used to share PLMN subscription information.

[0091] At operation 707, UE 102 stores the PLMN subscription information along with other 5GMM parameters in non-volatile memory, ensuring that the data is retained even if the device is powered off. The stored information includes a certificate holder list including SNPN1 206, SNPN2 208, and a GIN tagged as ID1.

[0092] At operation 709 , SIM1 is removed, prompting UE 102 to send a deregistration request to the AMF of PLMN1 202 .

[0093] At operation 711 SIM1 is deregistered and the connection is effectively closed.

[0094] At operation 713, UE 102 is inserted into SIM2, wherein the HPLMN of SIM2 is PLMN2.

[0095] At operation 715, UE 102 does not delete the PLMN subscription because SIM2 has a different SUPI and does not use the PLMN subscription associated with SIM1. In addition, UE 102 may use the PLMN subscription details whenever the same SIM1 is inserted.

[0096] At operation 717, UE 102 moves out of the coverage area of ​​PLMN1 202 and enters an area covered by PLMN3 204, SNPN1 206, and SNPN2 208. At operation 719, UE 102 initiates a registration request.

[0097] At operation 721, UE 102 receives confirmation from PLMN3 204 that the registration is accepted and thus the connection is established.

[0098] At operation 723, the AMF of PLMN1 202 sends a DL NAS message to the UE 102. The DL NAS message serves as confirmation of successful acceptance.

[0099] At operation 725, UE 102 stores the PLMN subscription information in non-volatile memory along with other 5GMM parameters and SUPI of SIM2, deleting the old subscription of SIM1. The stored information includes a certificate holder list including SNPN1 206, SNPN2 208, and a GIN tagged as ID1.

[0100] Fig. 8A and Figure 8BA series of operations 800 depicting a successful registration process for a UE 102 when handling different PLMNs and SNPNs in accordance with another embodiment of the present disclosure is shown.

[0101] At operation 801, UE 102 is inserted with SIM1 by a user, and the home public land mobile network (HPLMN) is PLMN1 202. The insertion of SIM1 triggers an initial network registration process.

[0102] At operation 803, UE 102 registers with the network using SIM1. During registration, UE 102 communicates with the AMF associated with PLMN1 202 and successfully completes the registration process.

[0103] At operation 805, the AMF of PLMN1 202 sends a DL NAS message to the UE 102. The DL NAS message is used to share PLMN subscription information.

[0104] At operation 807, UE 102 stores the PLMN subscription information along with other 5GMM parameters in non-volatile memory, ensuring that the data is retained even if the device is powered off. The stored information includes a certificate holder list including SNPN1 206, SNPN2 208, and a GIN tagged as ID1.

[0105] At operation 809, UE 102 moves out of the coverage area of ​​PLMN1 202 due to mobility and enters the coverage area of ​​SNPN1 206. When moving out of the coverage area of ​​PLMN1 202 and entering the coverage area of ​​SNPN1 206, at operation 811, UE 102 sends a registration request to the AMF of SNPN1 206, and at operation 813, SNPN1 206 accepts the registration request and sends a confirmation.

[0106] At operation 815, the UE 102 sends a deregistration request to the AMF of the PLMN1 202, wherein SIM1 is deregistered and the connection is effectively closed.

[0107] At operation 817 , SIM1 is removed, and at operation 819 , SIM2 is inserted, wherein the HPLMN is PLMN2.

[0108] Upon insertion of SIM2, UE 102 powers up in SNPN selection mode at operation 821. At operation 823, UE 102 finds the stored SNPN subscription details associated with SIM1 and deletes the old PLMN subscription details stored in UE 102 accordingly.

[0109] Fig.9A and Fig. 9BA series of operations 900 depicting a successful registration process for a UE 102 when handling different PLMNs and SNPNs in accordance with another embodiment of the present disclosure is shown.

[0110] At operation 901, UE 102 is inserted with SIM1 by a user, and the home public land mobile network (HPLMN) is PLMN1 202. Insertion of SIM1 triggers an initial network registration process.

[0111] At operation 903, UE 102 registers with the network using SIM1. During registration, UE 102 communicates with the AMF associated with PLMN1 202 and successfully completes the registration process.

[0112] At operation 905, the AMF of PLMN1 202 sends a DL NAS message to the UE 102. The DL NAS message is used to share PLMN subscription information.

[0113] At operation 907, UE 102 stores the PLMN subscription information along with other 5GMM parameters in non-volatile memory, ensuring that the data is retained even if the device is powered off. The stored information includes a certificate holder list including SNPN1 206, SNPN2 208, and a GIN tagged as ID1.

[0114] At operation 909, UE 102 moves out of the coverage area of ​​PLMN1 202 due to mobility and enters the coverage area of ​​SNPN1 206. When moving out of the coverage area of ​​PLMN1 202 and entering the coverage area of ​​SNPN1 206, at operation 911, UE 102 sends a registration request to the AMF of SNPN1 206, and at operation 913, SNPN1 206 rejects the registration request and sends a confirmation with 5GMM cause #3.

[0115] At operation 915, UE 102 marks SIM1 as invalid for the selected PLMN subscription.

[0116] At operation 917 , UE 102 moves to the coverage area of ​​SNPN2 208 .

[0117] Upon moving to the coverage area of ​​SNPN2 208, at operation 919, UE 102 does not attempt PLMN subscription in SNPN2 208 because UE 102 has marked SIM1 as invalid for the entire PLMN subscription.

[0118] At operation 921, the UE 102 is turned off and on.

[0119] At operation 923, the UE 102 selects SNPN1 206 from the PLMN subscription.

[0120] At operation 925 , UE 102 sends a registration request to SNPN1 206 .

[0121] At operation 927, the UE 102 receives the acceptance confirmation.

[0122] Fig.10 A series of operations 1000 depicting a successful registration process for a UE 102 when handling different PLMNs and SNPNs in accordance with another embodiment of the present disclosure is shown.

[0123] At operation 1001, UE 102 is inserted with two sets of certificates for SNPN1: Entry 1 (SNPN1 / SUPI1 / TLS1) and Entry 2 (SNPN1 / SUPI2 / TLS2). An initial registration procedure is triggered.

[0124] At operation 1003, UE 102 selects the certificate of entry 1 for registration.

[0125] At operation 1005 , UE 102 sends a registration request to SNPN1 206 using SUPI1.

[0126] At operation 1007, SNPN1 206 rejects the registration request with 5GMM cause #3. As a result of the rejection, at operation 1009, the UE marks SNPN1 as invalid for entry 1 only.

[0127] At operation 1011, UE 102 selects the certificate of entry 2 for registration.

[0128] At operation 1013, UE 102 sends a registration request to SNPN1 206 using SUPI2.

[0129] At operation 1015 , SNPN1 206 accepts the registration request, thereby successfully completing the registration process using entry 2 .

[0130] Fig.11 A flow chart of a method 1100 for optimizing the selection of a SNPN by a UE 102 according to an embodiment of the present disclosure is shown.

[0131] At operation 1102, method 1100 includes establishing a radio resource connection (RRC) connection with a PLMN or SNPN.

[0132] At operation 1104, method 1100 includes receiving, from a PLMN or SNPN, SNPN selection parameters associated with a PLMN subscription list corresponding to one or more universal subscriber identity modules (USIMs), wherein the SNPN selection parameters include the SNPN list and other configuration parameters (multiple configuration parameters) for one or more USIMs supported by the PLMN.

[0133] At operation 1106, the method 1100 further includes selecting at least one SNPN from the SNPN list based on the PLMN subscription list, and storing the SNPN selection parameters with the associated USIM. At operation 1106, the method 1100 further includes selecting at least one SNPN from the SNPN list based on the PLMN subscription list, and storing the PLMN subscription with the SUPI of the USIM associated with the PLMN subscription.

[0134] Fig.12 A flow chart of a method 1200 for optimizing the selection of a SNPN by a UE 102 according to another embodiment of the present disclosure is shown.

[0135] At operation 1202, the method 1200 includes selecting at least one SNPN from the SNPN list based on the PLMN subscription list and the associated plurality of SNPN selection parameters. The plurality of SNPN selection parameters associated with the PLMN subscription list corresponding to the one or more USIMs are pre-configured at the UE 102, and the plurality of SNPN selection parameters include the SNPN list and other configuration parameters for the one or more USIMs supported by the PLMN.

[0136] At operation 1204, method 1200 includes sending a registration request for the selected at least one SNPN to a network entity.

[0137] At operation 1206 , the method includes receiving a reject request message including a reject reason.

[0138] At operation 1208, method 1200 includes marking the USIM as invalid for the corresponding selected PLMN subscription.

[0139] Fig.13 A flow chart of a method 1300 for optimizing the selection of SNPN by the UE 102 according to another embodiment of the present disclosure is shown.

[0140] At operation 1302, method 1300 includes selecting at least one SNPN from a subscriber data list, wherein the subscriber data list includes multiple entries corresponding to each of the one or more SNPNs, each entry including at least one of a SUPI, an authentication certificate, a SNPN ID, and a verification status indicator associated with one or more USIMs, and pre-configuring the subscriber data list at the UE 102 and the corresponding network entity.

[0141] At operation 1304, method 1300 includes sending a registration request for the selected at least one SNPN to a network entity.

[0142] At operation 1306 , method 1300 includes receiving a reject request message including a reject reason.

[0143] At operation 1308, method 1300 includes marking a selected entry in the "Subscriber Data List" having an SNPN identifier of the current SNPN as invalid, or marking the current cell or tracking area identifier (TAI) or registration area or SNPN as prohibited for the corresponding selected entry of the at least one SNPN in the subscriber data list based on the received rejection reason.

[0144] At operation 1308, the method 1300 further includes: if a registration rejection message with 5GMM cause: #3 or #6 or #7 is received, the selected entry with the SNPN identifier of the current SNPN in the "Subscriber Data List" is marked as invalid until the UE 102 is turned off, the entry is updated, or the timer T3245 expires. If the network does not accept the mobile equipment (ME), the rejection cause #6 may be sent. If the UE is not allowed to operate 5G system (5GS) services, the rejection cause #7 may be sent.

[0145] In some embodiments, at operation 1308, the method 1300 further includes: if a registration rejection message with 5GMM cause: #12 is received, the current TAI is marked and stored in the list of "5GS prohibited tracking areas for regional provision of services" for the current SNPN and the selected entry of the "subscriber data list" or the selected PLMN subscription. In a prohibited tracking area (e.g., a tracking area in which the UE is not allowed to operate by subscription), if the UE requests service, or if the network initiates a deregistration procedure, a rejection cause #12 may be sent. The UE 102 should not further select a TAI list until the TAI is removed from the list of "5GS prohibited tracking areas for regional provision of services".

[0146] In some other embodiments, at operation 1308, the method 1300 further includes: if a registration rejection message with 5GMM cause: #13 or #15 is received, marking and storing the current TAI in the list of "5GS prohibited tracking areas for roaming" for the current SNPN and in the selected entry of the "subscriber data list" or the selected PLMN subscription. In the tracking area of ​​the PLMN, if the UE requests service or the network initiates a deregistration procedure, and the subscription provides roaming services to the UE through the tracking area but the UE is not in the tracking area, the rejection cause #13 may be sent. In a prohibited tracking area (e.g., a tracking area in which the UE is not allowed to operate), if the UE requests service or the network initiates a deregistration procedure, and the UE should find another allowed tracking area in the same PLMN or equivalent PLMN or the same SNPN or equivalent SNPN, the rejection cause #15 may be sent. The UE 102 should not further select the TAI list until the TAI is removed from the list of "5GS prohibited tracking areas for roaming".

[0147] In some other embodiments, at operation 1308, method 1300 includes: if a registration rejection message with 5GMM cause: #74 is received, the SNPN identification is marked and stored in a "temporarily prohibited SNPN" list maintained for the selected entry. In a cell belonging to the SNPN, if the UE requests access, or if the network initiates a deregistration procedure, and the UE is not subscribed to operate or the UE is not allowed to operate upload services in the cell, then the rejection cause #74 may be sent. The UE 102 should not select the SNPN for the selected entry until the SNPN is removed from the "temporarily prohibited SNPN" list.

[0148] In some other embodiments, at operation 1308, method 1300 includes: if a registration rejection message with 5GMM cause: #75 is received, marking the SNPN identifier and storing it in a "permanently prohibited SNPN" list maintained for the selected entry. Rejection cause #75 may be sent if the UE requests access to a cell belonging to a SNPN with a globally unique SNPN identifier, or if the network initiates a deregistration procedure for which the UE is not subscribed to operate, the UE's subscription has expired, or the UE is not allowed to operate upload services. The UE 102 should not select the SNPN for the selected entry until the SNPN is removed from the "permanently prohibited SNPN" list.

[0149] Fig.14 14 shows an embodiment of a system 1400 according to an embodiment of the present disclosure. Fig.14As shown, system 1400 includes a processor 1402 , a memory 1404 , a storage component 1406 , an input component 1408 , an output component 1410 , a communication interface 1412 , and a bus 1414 .

[0150] As used herein, processor 1402 means any type of computing circuit that may include hardware elements and software elements. Processor 1402 may be implemented as a multi-core processor, a single-core processor, or a combination of one or more multi-core processors and / or one or more single-core processors, a distributed processing system, etc. Processor 1402 may be a central processing unit (CPU), a graphics processing unit (GPU), an accelerated processing unit (APU), an application-specific integrated circuit (ASIC), or another type of processing component.

[0151] The memory 1404 includes a non-transitory computer-readable medium. The memory 1404 includes a random access memory (RAM), a read-only memory (ROM), and / or another type of dynamic or static storage device (e.g., flash memory, magnetic memory, and / or optical memory) that stores information and / or instructions used by the processor 1402. The memory 1404 includes machine-readable instructions that can be executed by the processor 1402. When executed by the processor 1402, these machine-readable instructions cause the processor 1402 to perform one or more method steps of the above-described embodiments.

[0152] The storage component 1406 stores information or software related to the operation and use of the system 1400. For example, the storage component 1406 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optical disk, and / or a solid-state disk), a compact disk (CD), a digital versatile disk (DVD), a floppy disk, a cassette, a magnetic tape, and / or another type of non-transitory computer-readable medium, and corresponding drives.

[0153] Input component 1408 may be configured to receive information, such as user input. For example, input component 1408 may include, but is not limited to, a touch screen display, a keyboard, a keypad, a mouse, a button, a switch, and / or a microphone. Output component 1410 is configured to transmit information from system 1440 to a user or other system using various devices and techniques customized for specific application needs. Output component 1410 may include visual output devices for presenting graphical or textual information, such as display screens (LCD, LED, OLED), projectors, and heads-up displays (HUDs). In addition, audio feedback and alerts are provided through auditory outputs of speakers and headphones, while tactile output devices such as vibration motors in smart phones or game controllers provide tactile feedback. Functionally, output components play a variety of roles, including displaying graphical user interface (GUI) elements for user interaction, delivering notifications and alerts through sound, visual indicators, or vibrations, and presenting complex data visualizations such as charts and graphs for easier understanding.

[0154] In an embodiment, the output component 1410 may be configured to receive processed data from the processor 1402, the processor 1402 determines the information to be communicated, and the output component 1410 may access the memory 1404 and the storage component 1406 to retrieve and display the stored information, such as documents, media files, or application states. In addition, the output component 1410 may be configured to meet the specific requirements of different applications, such as high-resolution visual output and immersive audio for gaming systems or clear and accurate data visualization and alarm mechanisms for industrial control systems. Through these different output methods, the output component 1410 ensures the effective communication of information, thereby enhancing both system functionality and user experience.

[0155] The present disclosure provides significant advantages and a robust method for optimizing the selection of SNPN by UE 102. By introducing SNPN selection parameters associated with PLMN subscription lists corresponding to multiple USIMs, the method ensures an efficient network selection process. Including a pre-configured SNPN list and other related configuration parameters supported by the PLMN enhances the ability of the UE to seamlessly select the most appropriate SNPN based on stored data. The capability is further refined by allowing the method to dynamically update the PLMN subscription list based on the connection state of the UE 102, thereby ensuring real-time adaptability and improved network performance. In addition, the present disclosure provides a priority list including user and certificate holder control, allowing customized and preference-based SNPN selection to meet different user needs and service requirements. In addition, the present disclosure also addresses the robustness of network selection by storing SNPN selection parameters in non-volatile memory, thereby retaining critical data across power cycles. The present disclosure also introduces a mechanism for effectively handling registration rejections by invalidating the associated USIM and corresponding SNPN entries based on predefined rejection reasons, which not only ensures the integrity of the PLMN subscription list, but also enhances the security and reliability of the network selection process.

[0156] This article discusses the various reasons for rejecting an access request. These reasons are outlined in 3GPP TS 24.501.

[0157] The above modules, processes, systems and devices may be implemented in hardware, hardware programmed by software, software instructions stored on a non-transitory computer-readable medium, or a combination thereof. Embodiments of the methods, processes, modules, devices and systems (or their subcomponents or modules) may be implemented on a general-purpose computer, a special-purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit components, an ASIC or other integrated circuit, a digital signal processor, a hard-wired electronic or logic circuit (such as a discrete element circuit), a programmed logic circuit (such as a programmable logic device (PLD), a programmable logic array (PLA), a field programmable gate array (FPGA), a programmable array logic (PAL) device, etc.). In general, any process capable of implementing the functions or steps described herein may be used to implement embodiments of the method, system or computer program product (software program stored on a non-transitory computer-readable medium).

[0158] In addition, embodiments of the disclosed methods, processes, modules, devices, systems, and computer program products can be easily implemented in whole or in part in software using, for example, an object or object-oriented software development environment that provides portable source code that can be used on a variety of computer platforms. Alternatively, embodiments of the disclosed methods, processes, modules, devices, systems, and computer program products can be implemented in part or in whole in hardware using, for example, standard logic circuits or very large scale integration (VLSI) designs. Other hardware or software can be used to implement embodiments, depending on the speed and / or efficiency requirements of the system, the specific functions, and / or the specific software or hardware systems, microprocessors, or microcomputers utilized.

[0159] In this disclosure, unless otherwise specifically stated, the use of the singular includes the plural, and the use of "or" means "and / or". In addition, the use of the terms "including" or "having" is non-limiting. Any range described herein will be understood to include the endpoints and all values ​​between the endpoints. The features of the disclosed embodiments may be combined, rearranged, omitted, etc. within the scope of this disclosure to produce additional embodiments. In addition, certain features may sometimes be used advantageously without the corresponding use of other features.

[0160] The accompanying drawings and the foregoing description give examples of embodiments. It will be appreciated by those skilled in the art that one or more of the elements described may be well combined into a single functional element. Alternatively, some elements may be divided into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, the order of the processes described herein may be changed, and are not limited to the manner described herein.

Claims

1. A method for optimizing selection of a standalone non-public network (SNPN) by a user equipment (UE), the method comprising: receiving, from a public land mobile network PLMN or SNPN, SNPN selection parameters associated with a PLMN subscription list corresponding to one or more global subscriber identity modules USIM, wherein the SNPN selection parameters include the SNPN list and a plurality of configuration parameters supported by the PLMN for the one or more USIMs; as well as At least one SNPN is selected from the SNPN list based on the PLMN subscription list, and SNPN selection parameters and a USIM associated with the SNPN selection parameters are stored.

2. The method according to claim 1, further comprising: At least one of the SNPN and the PLMN is selected based on a subscription permanent identifier SUPI associated with the one or more USIMs.

3. The method of claim 1, wherein SNPN selection parameters and the USIM associated with the SNPN selection parameters are stored in a non-volatile memory of the UE.

4. The method according to claim 1, further comprising: sending a registration request for the selected at least one SNPN to a network entity; receiving a request rejection message including a rejection reason; as well as Based on the received rejection cause, the corresponding entry of the selected at least one SNPN in the USIM and the PLMN subscription list associated with the SNPN selection parameter is invalidated. 5 . The method of claim 4 , wherein the rejection reason comprises at least one of rejection reason #3, rejection reason #6, and rejection reason #7.

6. A method for optimizing selection of a standalone non-public network (SNPN) by a user equipment (UE), the method comprising: selecting at least one SNPN from the SNPN list based on the PLMN subscription list and the associated plurality of SNPN selection parameters, wherein the plurality of SNPN selection parameters associated with a PLMN subscription list corresponding to one or more global subscriber identity modules USIM are preconfigured at the UE, and The multiple SNPN selection parameters include the SNPN list and multiple configuration parameters for the one or more USIMs supported by the PLMN.

7. A method for optimizing selection of a standalone non-public network (SNPN) by a user equipment (UE), the method comprising: Select at least one SNPN from the subscriber data list, wherein the subscriber data list comprises a plurality of entries corresponding to each of the one or more SNPNs, wherein each entry comprises at least one of a subscription permanent identifier SUPI, an authentication certificate, a SNPN ID and a verification status indicator, and The subscriber data list is pre-configured at the UE and the corresponding network entity.

8. The method according to claim 7, comprising: sending a registration request for the selected at least one SNPN to a network entity; receiving a request rejection message including a rejection reason; as well as Based on the received rejection cause, the current tracking area identity TAI or SNPN is marked as prohibited for the corresponding selected entry of the at least one SNPN in the subscriber data list.

9. The method of claim 8, wherein the rejection reason comprises at least one of a rejection reason #12, a rejection reason #13, a rejection reason #15, a rejection reason #74, and a rejection reason #75.

10. A system for optimizing selection of a standalone non-public network (SNPN) by a user equipment (UE), the system comprising: at least one memory; at least one processor operably connected to the at least one memory and configured to: receiving, from a public land mobile network PLMN or SNPN, SNPN selection parameters associated with a PLMN subscription list corresponding to one or more global subscriber identity modules USIM, wherein the SNPN selection parameters include the SNPN list and a plurality of configuration parameters for the one or more USIMs supported by the PLMN; as well as At least one SNPN is selected from the SNPN list based on the PLMN subscription list, and SNPN selection parameters and a USIM associated with the SNPN selection parameters are stored.

11. The system of claim 10, the at least one processor being further configured to select at least one of a SNPN and a PLMN based on a subscription permanent identifier (SUPI) associated with the one or more USIMs.

12. The system of claim 10, wherein SNPN selection parameters and the USIM associated with the SNPN selection parameters are stored in a non-volatile memory of the UE.

13. The system of claim 10, wherein the at least one processor is further configured to: sending a registration request for the selected at least one SNPN to a network entity; receiving a request rejection message including a rejection reason; and Based on the received rejection cause, the corresponding entry of the selected at least one SNPN in the USIM and the PLMN subscription list associated with the SNPN selection parameter is invalidated.

14. The system of claim 13, wherein the rejection reason comprises at least one of rejection reason #3, rejection reason #6, and rejection reason #7.

15. A system for optimizing selection of a standalone non-public network (SNPN) by a user equipment (UE), the system comprising: at least one memory; at least one processor operably connected to the at least one memory and configured to select at least one SNPN from the SNPN list based on the PLMN subscription list and the associated plurality of SNPN selection parameters, wherein a plurality of SNPN selection parameters associated with a PLMN subscription list corresponding to one or more global subscriber identity modules USIM are preconfigured at the UE, and The multiple SNPN selection parameters include the SNPN list and multiple configuration parameters for the one or more USIMs supported by the PLMN.

16. The system of claim 15, wherein the at least one processor is further configured to: sending a registration request for the selected at least one SNPN to a network entity; receiving a request rejection message including a rejection reason; and Based on the received rejection cause, the USIM associated with the SNPN selection parameter and the corresponding entry of the selected at least one SNPN in the PLMN subscription list are invalidated.

17. A system for optimizing selection of a standalone non-public network (SNPN) by a user equipment (UE), the system comprising: at least one memory; at least one processor operatively connected to the at least one memory and configured to select at least one SNPN from the subscriber data list, wherein the subscriber data list comprises a plurality of entries corresponding to each of the one or more SNPNs, wherein each entry comprises at least one of a subscription permanent identifier SUPI, an authentication certificate, a SNPN ID and a verification status indicator, and The subscriber data list is pre-configured at the UE and the corresponding network entity.

18. The system of claim 17, wherein the at least one processor is further configured to: sending a registration request for the selected at least one SNPN to a network entity; receiving a request rejection message including a rejection reason; and Based on the received rejection cause, the current tracking area identity TAI or SNPN is marked as prohibited for the corresponding selected entry of the at least one SNPN in the subscriber data list.

19. The system of claim 17, wherein the rejection reason comprises at least one of a rejection reason #12, a rejection reason #13, a rejection reason #15, a rejection reason #74, and a rejection reason #75.

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