Method and system for preventing service fallback of user equipment in a network

Abstract

The present disclosure provides a method (500) and a system (108) for preventing service fallback of a user equipment (UE) (104) in a network (106) The method (500) includes monitoring key performance indicators (KPIs) associated with a first network serving the UE (104) and detecting an outage condition based on the degradation of the monitored KPIs. Upon detection, the system triggers an application programming interface to update a user equipment usage type (UUT) parameter associated with the UE (104). Based on the updated UUT value, the system (108) determines whether the UE (104) is restricted from establishing connectivity with a second network and suppresses transmission of predefined messages toward an Access and Mobility Management Function (AMF) to prevent undesired service fallback. The method (500) and system (108) reduces unnecessary signaling and retry attempts, and ensure compliance with subscriber policies without requiring manual intervention at the UE (104).

Description

METHOD AND SYSTEM FOR PREVENTING SERVICE FALLBACK OF USER EQUIPMENT IN A NETWORK TECHNICAL FIELD

[0001] The present disclosure relates generally to the field of telecommunications. In particular, the present disclosure relates to a method and a system for preventing service fallback of a user equipment (UE) in a network.DEFINITIONS

[0002] As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.

[0003] The term “Unified Data Management (UDM)” used hereinafter in the specification refers to a network function responsible for managing subscriber data, such as user profiles, authentication information, and network access preferences.

[0004] The term “Home Subscriber Server (HSS)” used hereinafter in the specification refers to a network function that stores information of the subscribers, including their home network, service profiles, and security credentials.

[0005] The term “Access and Mobility Management Function (AMF)” used hereinafter in the specification refers to a network function responsible for managing user sessions, handling mobility procedures, and coordinating resource allocation.

[0006] The term “Session Management Function (SMF)” used hereinafter in the specification refers to a network function responsible for managing network services, such as QoS and policy control.

[0007] The term “Packet Data Network Gateway (PGW)” used hereinafter in the specification refers to a network function that provides connectivity to the internet and other external networks.

[0008] The term “Mobility Management Entity (MME)” used hereinafter in the specification refers to a network function responsible for managing user mobility and session continuity.

[0009] The term “5G core network” used hereinafter in the specification refers to the core network infrastructure of a 5G cellular network, which provides connectivity and services to 5G devices.

[0010] The term “Network Function Virtualization (NFV)” used hereinafter in the specification refers to a network architecture where various network functions are deployed as software applications on virtualized hardware or cloud infrastructure.

[0011] The term “Key Performance Indicator (KPI)” used hereinafter in the specification refers to a measurable value that indicates how well a specific activity, feature, or process is being executed.

[0012] The term “Non-Access Stratum (NAS)” used hereinafter in the specification refers to a layer in a 5G protocol stack responsible for higher-layer functions, such as security, mobility management, and session management.

[0013] The term “UE Usage Type (UUT)” used hereinafter in the specification refers to a classification or categorization of network traffic based on one or more characteristics, such as the type of data being transmitted, the applications generating the traffic, or the services being utilized. Further the UUT classification helps in managing one or more network resources efficiently, implementing one or more quality of service (QoS) policies, and optimizing traffic routing and prioritization.

[0014] The term “Radio Access Technology (RAT)” used hereinafter in the specification refers to the technology used by mobile devices or user equipment (UE) to connect to a cellular network. The RAT type refers to the specific protocol and standards that govern the way devices communicate with base stations, which are responsible for providing the wireless connection. Further, each RAT has its own set of protocols and standards for communication, which define the frequency bands, modulation techniques, and other parameters used for transmitting and receiving data. Examples of RATs include GSM (Global System for Mobile Communications), CDMA (Code Division Multiple Access), UMTS (Universal Mobile Telecommunications System), LTE (Long Term Evolution), and 5G. The choice of RAT depends on a variety of factors, including the network infrastructure, the available spectrum, and the mobile device's / device's capabilities. Mobile devices often support multiple RATs, allowing them to connect to different types of networks and provide optimal performance based on the available network resources.

[0015] The term “Update Location Answer (ULA)” used hereinafter in the specification refers to a part of a network procedure where the network updates the location of a mobile device (i.e. UE - User Equipment) in the network.

[0016] These definitions are in addition to those expressed in the art.BACKGROUND

[0017] The following description of related art is intended to provide background information pertaining to the field of the disclosure. This section may include certain aspects of the art that may be related to various features of the present disclosure. However, it should be appreciated that this section be used only to enhance the understanding of the reader with respect to the present disclosure, and not as admissions of prior art.

[0018] In telecommunications networks, the deployment of 5G technology offers enhanced connectivity, higher data speeds, and reduced latency compared to its predecessors. Subscribers configured for 5G-only services are provisioned with profiles that restrict their access exclusively to 5G networks, ensuring they benefit from the superior performance of these networks. However, network disruptions, particularly failures within the 5G network, pose significant challenges.

[0019] During a 5G network failure, subscribers may be redirected to fallback networks, such as 4G, to maintain service continuity. For 5G-only subscribers, this redirection is undesirable and unnecessary, as their subscription profiles explicitly prohibit mobility to 4G networks. Such redirection attempts lead to repeated service rejections from the core network, creating inefficiencies and impacting the user experience. Additionally, manual interventions are often required on the subscriber's part to resolve such issues, adding to operational complexity and delays.

[0020] Existing network mechanisms do not adequately address the scenario where 5G-only subscribers are affected by core network failures. The lack of an automated process to prevent these subscribers from being redirected to 4G networks results in wasted network resources and degraded service reliability.

[0021] Hence, there is a need to provide a method and a system that can address the shortcomings of existing solutions.SUMMARY OF THE DISCLOSURE

[0022] In an exemplary embodiment, a method for preventing service fallback of a user equipment (UE) in a network is described. The method includes monitoring, by a first network entity, one or more network performance parameters in a first network serving the UE. The method includes detecting, by the first network entity, an outage in the first network based on the monitored one or more performance parameters. The method includes triggering, by the first network entity, a firstapplication programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network. The method includes transmitting, by the first network entity, an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API. The method includes determining, by the first network entity, based on the updated UUT value, that the UE is restricted to establish a network connectivity with a second network. The method includes suppressing, by the first network entity, transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE in the second network.

[0023] In some embodiments, the method further includes determining, by the first network entity, that the UE is permitted to establish the network connectivity with the second network based on the updated UUT value and transmitting, by the first network entity, the first message to the second network entity.

[0024] In some embodiments, upon receiving the first message, the second network entity selects a network gateway within the second network based on the updated UUT value to manage the network connectivity of the UE with the second network.

[0025] In some embodiments, the method further includes allocating, by the first network entity, a time period for the UE to attempt to reconnect to the first network, wherein the UE transmits a reestablishment connection request to the second network entity to reconnect to the first network on expiration of the allocated time period.

[0026] In some embodiments, the first message is an “Unknown 5GS Subscription” message.

[0027] In some embodiments, the first network is a fifth generation (5G) network and second network is a fourth generation (4G) network.

[0028] In an exemplary embodiment, a system for preventing service fallback of a user equipment (UE) in a network is described. The system includes a monitoring unit, a detection unit, a transmitting unit, and a control unit at a first network entity. The monitoring unit, the detection unit, the transmitting unit, and the control unit are communicable coupled to operatively coupled with one another. The monitoring unit is configured to monitor one or more network performance parameters in a first network serving the UE. The detection unit is configured to detect an outage in the first network based on the monitored one or more performance parameters. The detection unit is further configured to trigger a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network. The transmitting unit is configured to transmit an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API. The control unit is configured to determine based on the updated UUT value, that the UE is restricted to establish a network connectivity with a second network and suppress transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE in the second network.

[0029] In an exemplary embodiment, user equipment (UE) for preventing service fallback in a network, the UE includes a memory and a processor communicably coupled to the memory, where the processor is configured to transmit, to a system, a request to monitor one or more performance parameters to detect an outage in a first network, and receive from the system, a response associated with the request. The response is received based on monitoring, by the system, the one or more performance parameters in the first network serving the UE, detecting, by the system,the outage in the first network based on the monitored one or more performance parameters, triggering, by the system, a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network, transmitting, by the system, an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API, determining, by the system, based on the updated UUT value, that the UE is restricted to establish a network connectivity with a second network and suppressing, by the system, transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE in the second network.OBJECTIVES OF THE DISCLOSURE

[0030] Some of the objectives of the present disclosure, which at least one embodiment herein satisfies, are as follows:

[0031] An objective of the present disclosure is to provide a method and a system for preventing the redirection of subscribers configured for a first network (5G) to a second network (4G) during a failure in the first network, thereby avoiding unnecessary service rejection attempts.

[0032] Another objective of the present disclosure is to provide a method and a system for enabling automating network responses during the first network failure by utilizing subscriber profiles and signaling mechanisms to ensure service continuity without manual intervention.

[0033] Another objective of this disclosure is to provide a method and a system for optimizing network resource utilization by dynamically managing the connectivity of a user equipment during the first network failure, ensuring efficient allocation of resources and preventing unnecessary redirection to fallback networks.

[0034] Yet another objective of the present disclosure is to provide a method and a system for improving the user experience by eliminating unnecessary connection attempts to unavailable networks during core network outages.

[0035] Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

[0036] The accompanying drawings, which are incorporated herein, and constitute a part of this disclosure, illustrate exemplary embodiments of the disclosed methods and systems in which like reference numerals, refer to the same parts throughout the different drawings. Components in the drawings are not necessarily to scale; emphasis is instead being placed upon clearly illustrating the principles of the present disclosure. Some drawings may indicate the components using block diagrams and may not represent the internal circuitry of each component. It will be appreciated by those skilled in the art that disclosure of such drawings includes disclosure of electrical components, electronic components, or circuitry commonly used to implement such components.

[0037] FIG. 1 illustrates an exemplary network architecture in which or with which a system configured for preventing service fallback of a user equipment (UE) in a network may be implemented, in accordance with an embodiment of the present disclosure.

[0038] FIG. 2A illustrates an exemplary diagram of a system architecture for preventing service fallback of the UE in the network, in accordance with an embodiment of the present disclosure.

[0039] FIG. 2B illustrates an exemplary block diagram of the system configured for preventing service fallback of the UE in the network, in accordance with an embodiment of the present disclosure.

[0040] FIG. 3 illustrates an exemplary flow diagram of a method for preventing service fallback of the UE in the network, in accordance with an embodiment of the present disclosure.

[0041] FIG. 4 illustrates another exemplary network architecture with implementation of the system preventing service fallback of the UE in the network, in accordance with an embodiment of the present disclosure.

[0042] FIG. 5 illustrates an exemplary flowchart of the method for preventing service fallback of the UE in the network, in accordance with an embodiment of the present disclosure.

[0043] FIG. 6 illustrates an example computer system in which or with which the embodiments of the present disclosure may be implemented.

[0044] The foregoing shall be more apparent from the following more detailed description of the disclosure.LIST OF REFERENCE NUMERALS100 - Network architecture102 -User(s)104 - User Equipments (UEs)106 - Network108 - System200A - System Architecture202, 416 - Unified Data Management (UDM)204 - Home Subscriber Server (HSS)206, 408 - Access and Mobility Management Function (AMF)208, 410 - Session Management Function (SMF)210 -Packet Data Network Gateway (PGW) / 4G Packet Data Network Gateway (4G PGW)212 - Mobility Management Entity (MME)200B - Block diagram214 - One or more processor(s)216 - Memory218 - Interface(s)220 -Monitoring unit222 - Detection unit224 -Transmitting unit226 - Control unit210 - Database300 - Flow diagram301 - UDM provisioning unit (PS)302, 304, 306, 308, 310, 312, 314, 316- Steps 400- Network architecture402- Radio Access Network (RAN)404- User Plane Function (UPF)412- Network Exposure Function (NEF)414- Policy Control Function (PCF)418- Binding Support Function (BSF)422- Equipment Identity Register (EIR)424- Diameter Routing Agent (DRA)426- Charging Function-Policy Control (CHF-PC) 428- Network Slice Selection Function (NSSF) 430- Signaling Transfer Point (STP)432- Network Data Analytics Function (NWDAF) 434- Short Message Service Function (SMSF) 436- Gateway Mobile Location Center (GMLC) 438- Location Management Function (LMF) 440- Location Services (LCS client)500 - Method Flow Diagram600 - Computer system610 - External Storage Device620 - Bus630 - Main Memory640 - Read Only Memory650 - Mass Storage Device660 - Communication Port670 - ProcessorDETAILED DESCRIPTION

[0045] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address any of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein. Example embodiments of the present disclosure are described below, as illustrated in various drawings in which like reference numerals refer to the same parts throughout the different drawings.

[0046] The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in theart with an enabling description for implementing an exemplary embodiment. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the disclosure as set forth.

[0047] Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.

[0048] Also, it is noted that individual embodiments may be described as a process that is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional steps not included in a figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination can correspond to a return of the function to the calling function or the main function.

[0049] The word “exemplary” and / or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the subject matter disclosed herein is not limited by such examples. In addition, any aspect or design described herein as “exemplary” and / or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,”and other similar words are used in either the detailed description or the claims, such terms are intended to be inclusive like the term “comprising” as an open transition word without precluding any additional or other elements.

[0050] Reference throughout this specification to “one embodiment” or “an embodiment” or “an instance” or “one instance” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0051] The terminology used herein is to describe particular embodiments only and is not intended to be limiting the disclosure. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any combinations of one or more of the associated listed items. It should be noted that the terms “mobile device”, “user equipment”, “user device”, “communication device”, “device” and similar terms are used interchangeably for the purpose of describing the invention. These terms are not intended to limit the scope of the invention or imply any specific functionality or limitations on the described embodiments. The use of these terms is solely for convenience and clarity of description. The invention is not limited to any particular type of device or equipment, and it should be understood that otherequivalent terms or variations thereof may be used interchangeably without departing from the scope of the invention as defined herein.

[0052] While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment, as well as other embodiments of the disclosure, will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

[0053] Wireless communication technology has rapidly evolved over the past few decades. The first generation of wireless communication technology was analog, offering only voice services. Further, text messaging and data services became possible when the second-generation (2G) technology was introduced. The third generation (3G) technology marked the introduction of high-speed internet access, mobile video calling, and location-based services. The fourth generation (4G) technology revolutionized the wireless communication with faster data speeds, improved network coverage, and security. Currently, fifth generation (5G) technology is being deployed, offering significantly faster data speeds, lower latency, and the ability to connect many devices simultaneously. Further, 6G successor to 5G is expected to provide significantly high data speed with reduced latency, which may offer improved connectivity for a vast number of devices concurrently. The capabilities of 6G enable new types of applications and services, such as advanced augmented reality (AR) and virtual reality (VR), holographic communications, and more immersive digital experiences. These advancements represent a significant leap forward from previous generations, enabling enhanced mobile broadband, improved Internet of Things (loT) connectivity, and more efficient use of network resources. The sixth generation (6G)technology promises to build upon these advancements, pushing the boundaries of wireless communication even further. While the 5G technology is still being rolled out globally, research and development into the 6G are rapidly progressing, with the aim of revolutionizing the way of connecting and interacting with technology.

[0054] In modern cellular networks, ensuring seamless connectivity and uninterrupted service for subscribers is of paramount importance. With the increasing reliance on mobile services for daily communication, entertainment, work, and other activities, any network failure can have significant consequences. Network failures (such as outages, degraded signal quality, or disruptions in coverage) may severely affect the user experience, leading to poor performance, dropped calls, slow data speeds, or even complete service loss. To mitigate these risks and maintain service continuity, network operators deploy a variety of strategies to minimize the impact of such failures and ensure users remain connected.

[0055] One of the most common strategies for maintaining connectivity in case of network failures is redirecting users to alternative networks. For example, if a subscriber's device is connected to a 5G network and a failure occurs in that network, the operator may automatically reroute the device to an available 4G (LTE) network. This redirection ensures that the subscriber can continue to access essential services like calls, text messages, and data, even if the preferred 5G network is temporarily unavailable.

[0056] However, while this strategy can prevent a complete service outage, it often comes with trade-offs in terms of service quality. Redirecting a 5G user to 4G may lead to noticeable performance degradation, as the two networks are built on different technologies and have different capabilities. Moreover, this redirection can lead to service disruptions and poor performance for devices that are exclusively designed to operate on 5G networks.

[0057] Hence, there is a need to provide a method and a system that can address the shortcomings of existing solutions.

[0058] The present disclosure provides the method and the system to prevent unnecessary redirection of 5G-only devices to 4G networks during 5G network failures. The method and the system aims to provide a more reliable and efficient user experience by restricting network access based on device capabilities. The system detects an issue (failure) within a first network or a 5G Core (5GC) network through a degradation in Key Performance Indicators (KPIs). Once the failure is detected, the system may trigger the User Equipment Usage Type (UUT) application programming interface (API) for the affected Home Public Land Mobile Network (HPLMN) or Visited Public Land Mobile Network (VPLMN) via a provisioning unit. This action allows the network to initiate the necessary redirection of affected services. After enabling UUT, the Home Subscriber Server (HSS) may begin sending the updated UUT value in the Update Location Answer (ULA) message, as per the HPLMN / VPLMN configuration. At the same time, the UDM may set an "Unknown 5GS Subscription" flag in the AMF (Access and Mobility Management Function) registration response, but only for subscribers who are not restricted to New Radio (NR) exclusively. Subscribers with NR-only profiles will not receive this update.

[0059] The Mobility Management Entity (MME) may then use the updated UUT value to select a 4G Packet Gateway (PGW) to maintain service continuity. To prevent further attempts to connect to the 5GC network, the AMF may send a "N1 Mode Not Allowed" message within the Non-Access Stratum (NAS) code. This ensures that devices avoid retrying to connect to the 5GC network until the failure is resolved.

[0060] This workflow ensures a seamless transition to 4G for users affected by the 5G failures, minimizing service disruption and maintaining service quality while the issue is being addressed.

[0061] The various embodiments throughout the disclosure will be explained in more detail with reference to FIG. 1 - FIG. 6.

[0062] FIG. 1 illustrates an exemplary network architecture (100) in which or with which a system (108) configured for preventing service fallback of a user equipment (UE) (104) in a network (106) may be implemented, in accordance with an embodiment of the present disclosure.

[0063] As illustrated in FIG. 1, the network architecture (100) may include one or more user equipment (UE) ( 104- 1 , 104-2... 104-N) associated with one or more users (102-1, 102-2... 102 -N) in an environment. A person of ordinary skill in the art will understand that one or more users (102-1, 102-2... 102-N) may collectively referred to as the users (102). Similarly, a person of ordinary skill in the art will understand that one or more UEs (104-1, 104-2... 104-N) may be collectively referred to as the UE (104). Although only three UEs (104) are depicted in FIG. 1, however, any number of the UE (104) may be included without departing from the scope of the ongoing description.

[0064] In an embodiment, the UE (104) may include smart devices operating in a smart environment, for example, an Internet of Things (loT) system. In such an embodiment, the UE (104) may include, but is not limited to, smartphones, smart watches, smart sensors (e.g., mechanical, thermal, electrical, magnetic, etc.), networked appliances, networked peripheral devices, networked lighting system, communication devices, networked vehicle accessories, networked vehicular devices, smart accessories, tablets, smart television (TV), computers, smart security system, smart home system, other devices for monitoring or interacting with or for the users (102) and / or entities, or any combination thereof. A person of ordinary skill in the art will appreciate that the UE (104) may include, but not limited to, intelligent, multisensing, network-connected devices, that may integrate seamlessly with each otherand / or with a central server or a cloud-computing system or any other device that is network-connected.

[0065] Additionally, in some embodiments, the UE (104) may include, but is not limited to, a handheld wireless communication device (e.g., a mobile phone, a smartphone, a phablet device, and so on), a wearable computer device (e.g., a headmounted display computer device, a head-mounted camera device, a wristwatch computer device, and so on), a Global Positioning System (GPS) device, a laptop computer, a tablet computer, or another type of portable computer, a media playing device, a portable gaming system, and / or any other type of computer device with wireless communication capabilities, and the like. In an embodiment, the UE (104) may include, but are not limited to, any electrical, electronic, electromechanical, or equipment, or a combination of one or more of the above devices, such as virtual reality (VR) devices, augmented reality (AR) devices, laptop, a general-purpose computer, desktop, personal digital assistant, tablet computer, mainframe computer, or any other computing device, wherein the UE (104) may include one or more in-built or externally coupled accessories including, but not limited to, a visual aid device such as a camera, an audio aid, a microphone, a keyboard, and input devices for receiving input from the user (102) or the entity such as touchpad, touch-enabled screen, electronic pen, and the like. A person of ordinary skill in the art will appreciate that the UE (104) may not be restricted to the mentioned devices and various other devices may be used.

[0066] Referring to FIG. 1, the UE (104) may communicate with the system (108) through a network (wireless communication network) (106) for sending or receiving various types of data. In an embodiment, the network (106) may include at least one of a fifth generation (5G) network, sixth generation (6G) network, or the like. The network (106) may enable the UE (104) to communicate with other devices in the network architecture (100) and / or with the system (108). The network (106) may include a wireless card or some other transceiver connection to facilitate thiscommunication. In another embodiment, the network (106) may be implemented as, or include any of a variety of different communication technologies such as a wide area network (WAN), a local area network (LAN), a wireless network, a mobile network, a Virtual Private Network (VPN), the Internet, the Public Switched Telephone Network (PSTN), or the like.

[0067] In an embodiment, the network (106) may include, by way of example but not limitation, at least a portion of one or more networks having one or more nodes that transmit, receive, forward, generate, buffer, store, route, switch, process, or a combination thereof, etc. one or more messages, packets, signals, waves, voltage or current levels, some combination thereof, or so forth. The network (106) may also include, by way of example but not limitation, one or more of a wireless network, a wired network, an internet, an intranet, a public network, a private network, a packet-switched network, a circuit-switched network, an ad hoc network, an infrastructure network, a Public-Switched Telephone Network (PSTN), a cable network, a cellular network, a satellite network, a fiber optic network, or some combination thereof.

[0068] In an embodiment, the UE (104) is communicatively coupled with the network (106). The network (106) may receive a connection request from the UE (104). The network (106) may send an acknowledgment of the connection request to the UE (104). The UE (104) may transmit a plurality of signals in response to the connection request.

[0069] In an embodiment, the UE (104) is registered with a Home Public Land Mobile Network (HPLMN) and is capable of roaming in a Visited Public Land Mobile Network (VPLMN). The UE (104) establishes connectivity with the system (108) deployed in a core network. In an aspect, the UE (104) may transmit a request to monitor one or more performance parameters to detect an outage in a first network. Furthermore, the UE (104) may receive a response associated with the request, which is received based on the system (108) being configured to prevent service fallback forthe UE (104). The process of preventing the service fallback of the UE (104) is described in further detail with reference to FIG. 2 to FIG. 6.

[0070] Although FIG. 1 shows exemplary components of the network architecture (100), in other embodiments, the network architecture (100) may include fewer components, different components, differently arranged components, or additional functional components than depicted in FIG. 1. Additionally, or alternatively, one or more components of the network architecture (100) may perform functions described as being performed by one or more other components of the network architecture (100).

[0071] FIG. 2A illustrates an exemplary diagram of a system architecture (201) for preventing service fallback of the UE (104) in the network (106), in accordance with an embodiment of the present disclosure. FIG. 2A is explained in conjunction with FIGI. FIG. 2A describes the system architecture (201) involved in the present disclosure for preventing service fallback of the UE (104) that is a 5G-only subscriber to a second network during the network outage of a first network. In an aspect, the first network is a 5G network, and the second network is a 4G network.

[0072] The system architecture (201) comprises one or more components such as a Unified Data Management (UDM) (202), a Home Subscriber Server (HSS) (204), an Access and Mobility Management Function (AMF) (206), a Session Management Function (SMF) (298), a Packet Gateway (PGW) (210), and a Mobility Management Entity (MME) (212).

[0073] The UDM (202) is a component in the first network (5G) responsible for managing subscription data and user profiles for 5G subscribers. The UDM (202) includes active monitoring and coordination with other network functions. The UDM (202) plays a critical role in failure detection by monitoring the operational status of the first network (5G) across both Home Public Land Mobile Network (HPLMN) andVisited Public Land Mobile Network (VPLMN) of the UE (104). For example, in the event of a failure in the first network (5G), the UDM (202) communicates directly with the HSS (204) using a UE Usage Type (UUT) application programming interface (API) to update one or more UUT values. The UUT describes the type of service or the usage characteristics that the UE (104) is allowed to use in a given network. The UUT value helps the network determine how the UE (104) should be handled regarding service availability and access, particularly in the context of 5G and 4G networks. Additionally, the UDM (202) ensures the redirection of impacted subscribers by sending an “Unknown 5GS Subscription” error code to the AMF (206) over an N8 interface.

[0074] The error code allows the AMF (206) to identify the UE (104) unable to connect and prevent repeated connection attempts. Simultaneously, the UDM (202) interacts with the SMF (208) over an N10 interface to maintain session and mobility management for unaffected subscribers. For example, if a subscriber in the first network experiences a failure, the UDM (202) identifies the issue, informs the HSS (204) to activate fallback settings, and coordinates with the AMF (206) to notify the UE (104), and if required redirecting them to the second network seamlessly. This ensures service continuity while optimizing resource utilization in the first network. The N8 interface between the UDM (202) and AMF (206) enables the exchange of subscription updates and the transmission of error codes, such as the “Unknown 5GS Subscription” code, which helps the AMF (206) identify and redirect affected subscribers which are not specified as NR only subscriber. The “Unknown 5GS Subscription” error is used in the 5G network registration to indicate that the AMF (206) is not able to locate the necessary subscriber data in the network's subscriber database, typically managed by the HSS (204) or the UDM (202). The error code suggests that the UE (104) does not have a valid or registered 5G subscription, so it cannot be granted access to the first network or 5G services.

[0075] In an embodiment, the function of the UDM (202) includes a feature that prevents the “Unknown 5GS Subscription” error from being sent in the registration response to the AMF (206) under specific scenarios, such as when the HPLMN or the VPLMN is down or experiencing an outage. This feature applies explicitly to the UE (104) that only allows New Radio (NR) (first network) access and that UE (104) is restricted from accessing the second network (4G) by their subscription profiles. There is no requirement to redirect their traffic to the second network during an outage in the first network. This approach prevents unnecessary redirection attempts and ensures compliance with subscriber profile restrictions or the UE (104).

[0076] Conversely, the UDM (202) sends the “Unknown 5GS Subscription” error code to the AMF (206) in scenarios when the UE (104) is allowed to redirect into the second network. Upon receiving the “Unknown 5GS Subscription” error code, the AMF (206) responds by transmitting an N1 mode not allowed message in the 5G Mobility Management (MM) cause towards the UE (104). The N1 Mode defines the interaction between the UE (104) and the AMF (206) during tasks such as UE registration, authentication, and mobility management. This ensures that the UE (104) does not attempt further connection attempts to the first network.

[0077] The HSS (204) coordinates fallback scenarios when the first network experiences failures. With a direct communication link to the UDM (202), the HSS (204) receives updates regarding the UE (104) that is affected, including the fallback eligibility status of the affected subscribers. For example, upon notification from the UDM (202), the HSS (204) updates the User Update Trigger (UUT) value in an Update Location Answer (ULA) message and communicates it to the MME (212) over an S6a interface. The ULA message ensures that the network components (such as the AMF (206) or the MME (212)) are updated with the correct information about the registration and location status of the UE (104), allowing for proper management of connectivity, mobility, and services. The S6a interface is an important part of the 5G core networkarchitecture (and also in 4G LTE) and is primarily responsible for the communication between the HSS (204) and the UDM (202). The S6a interface plays a crucial role in subscriber authentication, authorization, and the management of user profiles. The S6a interface is used for exchanging information related to subscriber data, such as authentication credentials, subscription details, and user equipment (UE) capabilities. The S6a interface enables the MME (212) to identify eligible subscribers and coordinate their transition to the second network. The communication ensures that the second network can handle subscriber fallback requests effectively. Moreover, the HSS (204) collaborates with the MME (212) to facilitate a transition for eligible subscribers from the first network to the second network, ensuring minimal disruption to services. For example, if the UE (104) is not restricted to 5G-only subscriber and it is allowed to redirect to the second network (4G), the HSS (204) ensures the UE (104) profile is updated to allow access to the second network, thereby preserving continuity of service.

[0078] The AMF (206) is a critical network function in the first network that manages signaling and mobility for the UE (104). The AMF (206) handles registration, connection establishment, and session control by interacting with the UDM (202) and the UE (104). The AMF (206) also addresses fallback scenarios during first network failures. When the UDM (202) detects a failure and sends the “Unknown 5GS Subscription” error code via the N8 interface, the AMF (206) identifies affected NR-only subscribers and prevents repeated connection attempts, reducing unnecessary signaling. The AMF (206) efficiently notifies the UE (104) that is impacted by sending an “N1 mode not allowed” message, instructing the UE (104) to switch to fallback networks, such as the second network. Additionally, the AMF (206) collaborates with the SMF (208) to maintain session continuity for unaffected subscribers, ensuring minimal disruption to active sessions.

[0079] The SMF (208) ensures session continuity during fallback scenarios triggered by the first network failure. The SMF (208) communicates with the UDM (202) over the N10 interface to handle session-related processes and determine the fallback requirements for affected subscribers. The N10 interface between the UDM (202) and the SMF (208) facilitates session signaling, allowing the SMF (208) to manage ongoing sessions and reallocate resources efficiently during fallback scenarios. For unaffected subscribers, the SMF (208) ensures that their active sessions remain uninterrupted, maintaining a seamless user experience. Simultaneously, the SMF (208) coordinates with other network components, such as the AMF (206), to reallocate resources efficiently for fallback-eligible subscribers, ensuring optimal network capacity utilization.

[0080] The MME (212) is configured to enable backward compatibility for the UE (104), transitioning to the second network during fallback scenarios. The MME (212) receives updated UUT values from the HSS (204) via the S6a interface, which helps identify subscribers eligible for fallback. The S6a interface between the HSS (204) and MME (212) ensures that fallback-related subscriber parameters, such as updated UUT values, are transmitted to the MME (212). Once identified, the MME (212) executes traffic redirection by selecting an appropriate Packet Data Network Gateway (PGW) (210) to manage data services for these subscribers. Additionally, the MME (212) ensures efficient load balancing by managing the second network resources to integrate fallback subscribers seamlessly, minimizing the risk of congestion and maintaining the quality of service for the existing 4G users.

[0081] The PGW (210) manages fallback scenarios for subscribers transitioning from the first network to the second network due to the first network failures. The PGW (210) ensures fallback data routing by establishing and maintaining data sessions for these subscribers, enabling seamless access to external networks.Moreover, the PGW (210) guarantees service continuity by preventing disruptions in data services, even during transition.

[0082] Thus, the system architecture (201) enables efficient management of service fallback during outages in the first network by dynamically coordinating subscriber profile updates, access control signaling, and mobility management across core network functions. By selectively restricting or permitting redirection of the UE (104) based on subscription policies and updated UUT values, the system architecture (201) prevents unauthorized fallback for NR-only subscribers while ensuring seamless continuity of service for eligible subscribers. This coordinated approach minimizes unnecessary signaling, optimizes network resource utilization, and ensures policy-compliant handling of service fallback scenarios across the HPLMN and the VPLMN.

[0083] FIG. 2B illustrates an exemplary block diagram of the system (108) configured for preventing service fallback of the UE (104) in the network, in accordance with an embodiment of the present disclosure. FIG. 2B is explained in conjunction with FIGs 1 and 2A.

[0084] In an exemplary implementation, the system (108) may be embedded within, or operatively associated with, a first network entity. In an aspect, the first network entity may include at least the UDM (202) and the HSS (204) of the core network. In such an implementation, the UDM includes a provisioning unit that hosts and executes the system (108) as a logical module. The provisioning unit is configured to manage subscriber profiles and service-related parameters and to implement processing, monitoring, detection, transmission, and control functions for preventing service fallback of the UE (104).

[0085] In an embodiment, the system (108) may include one or more processor(s) (214). The one or more processor(s) (214) may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors,central processing units, logic circuitries, and / or any devices that process data based on operational instructions. Among other capabilities, the one or more processor(s) (214) may be configured to fetch and execute computer-readable instructions stored in memory (216) of the system (108). The memory (216) may be configured to store one or more computer-readable instructions or routines in a non-transitory computer-readable storage medium, which may be fetched and executed to perform the one or more network procedures. The memory (216) may include any non-transitory storage device, including, for example, volatile memory such as a Random-Access Memory (RAM), or a non-volatile memory such as an Erasable Programmable Read Only Memory (EPROM), a flash memory, and the like.

[0086] In an embodiment, the system (108) may include an interface(s) (218). The interface(s) (218) may include a variety of interfaces, for example, interfaces for data input and output devices (VO), storage devices, and the like. In an embodiment, the interface(s) (218) may facilitate communication through the system (108).

[0087] In an exemplary embodiment, the system (108) may include one or more functional units with functions that include, but are not limited to, testing, storage, and peripheral functions, such as a monitoring unit (220), a detection unit (222), a transmitting unit (224), and a control unit (226). In an implementation, the one or more functional units may be operatively coupled to one another. The interface(s) (218) may also provide a communication pathway for the one or more functional units of the system (108).

[0088] In an embodiment, the one or more functional units may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the processor(s) (214). In examples described herein, such combinations of hardware and programming may be implemented in several different ways. For example, the programming for the one or more functional units such as the monitoring unit (220),the detection unit (222), the transmitting unit (224), and the control unit (226) may be processor-executable instructions stored on a non-transitory machine-readable storage medium and the hardware for the one or more functional units may comprise a processing resource (for example, the one or more processors 202), to execute such instructions. In the present examples, the machine-readable storage medium may store instructions that, when executed by the processing resource, implement the one or more functional units. In such examples, the system (108) may comprise the machine-readable storage medium storing the instructions and the processing resource to execute the instructions, or the machine-readable storage medium may be separate but accessible to the system (108) and the processing resource. In other examples, the one or more functional units may be implemented by electronic circuitry.

[0089] In an embodiment, the system (108) may include a database (228) that may store data that may be generated as a result of functionalities implemented by any of the components of the processor (202) or the one or more functional units. In an embodiment, the database (228) may be indicative of including, but not limited to, a relational database, a distributed database, a cloud-based database, or the like.

[0090] In an embodiment, the one or more function units may be present at the same location or may be distributed at different locations within the system (108). Additionally, a unit of the system (108) may comprise one or more sub-units, which can be centralized or distributed at various locations and may collectively be referred to as that particular unit. For ease of reference, FIG. 2B depicts units / components of the system (108) by way of representation of blocks and FIG. 2B does not represent the internal circuitry or connections of each component / unit of the system (108). It will be appreciated by those skilled in the art that the disclosure of such drawings / block diagrams includes disclosure of electrical components and connections between said electronic components, and electronic components or circuitry commonly used to implement such components.

[0091] Further, in accordance with the present disclosure, it is to be acknowledged that the functionality described for the one or more functional units can be implemented interchangeably. While specific embodiments may disclose a particular functionality of these units for clarity, it is recognized that various configurations and combinations thereof are within the scope of the disclosure. The functionality of specific units as disclosed in the disclosure should not be construed as limiting the scope of the present disclosure. Consequently, alternative arrangements and substitutions of units, provided they achieve the intended functionality described herein, are considered to be encompassed within the scope of the present disclosure.

[0092] In an embodiment, the transmitting unit (224) includes a transmitter having capabilities to transmit data / signals.

[0093] In an embodiment, the system (108) is configured for preventing service fallback of the UE (104) with the help of the interconnection between the one or more functional units of the system (108).

[0094] In an embodiment, the monitoring unit (220) is configured to monitor one or more network performance parameters in a first network serving the UE (104). In an example, the first network serving the UE (104) may indicate the 5GCore network. The one or more network performance parameters are key performance indicators (KPIs), which are one or more measurable values that indicate how effectively the 5Gcore (5GC) network or any telecommunications network is working. The monitoring used herein refers to a process of continuously observing or tracking the one or more KPIs within the network (106). The one or more network performance parameters may include, but are not limited to, a latency, a throughput, a packet loss rate, and a signal strength.

[0095] As used herein, latency is a time taken for data to travel from a source to a destination in a network. Further, as used herein, ‘throughput’ is an amount of datatransferred over the network within a given time frame. Also, as used herein, ‘packet loss rate’ is a percentage of one or more packets lost or dropped during transmission over the network. Further, as used herein, ‘signal strength’ or quality of the signal received by the UE (104), within the network.

[0096] The monitoring unit (220) may continuously monitor the one or more network performance parameters (KPIs) to promptly identify any network problems. Additionally, these KPIs are used to assess and monitor one or more aspects of performance and functionality.

[0097] In an embodiment, the detection unit (222) is configured to detect an outage in the first network based on the one or more network performance parameters monitored by the monitoring unit (220). The outage used herein refers to any condition indicating reduced operational capability, service degradation, or loss of availability of the first network. The monitoring is performed to identify degradation, abnormal behavior, or outage conditions in the first network that may impact service continuity for the UE (104), thereby enabling timely detection and initiation of network-controlled actions to prevent undesired service fallback.

[0098] In an exemplary implementation, the monitoring unit (220) may be configured to monitor the one or more network performance parameters (KPIs), by receiving periodic performance reports and real-time event notifications from the one or more network functions in the first network, such as the AMF (206), the SMF (208), and other core network functions. For example, the monitoring unit (220) tracks registration request failure counts and signaling response times reported by the AMF (206), session establishment delays reported by the SMF (208), and availability or heartbeat status of subscriber data services reported by the UDM (202). The detection unit (222) may evaluate the monitored one or more network performance parameters (KPIs) by comparing their values against one or more predefined thresholds to determine whether a degradation or outage condition exists. Further, a failure in the 5GCore (5GC) network is identified when the values of the one or more network performance parameters fall below one or more predefined thresholds, thereby indicating impaired network health or service availability. Such KPI degradation reflects an outage or service impact in the first network (5GC network).

[0099] In an embodiment, upon detecting the outage or service degradation in the first network, the detection unit (222) may be configured to trigger a first application programming interface (API) for an affected home public land mobile network (HPLMN) or visited public land mobile network (VPLMN). The affected HPLMN and the affected VPLMN, respectively, refer to an HPLMN where the outage is detected and the VPLMN where the outage is detected. The HPLMN refers to the network of the mobile operator to which the UE (104) (or subscriber) is originally subscribed. The HPLMN is the home network where the subscriber's user profile, service subscription, and billing details are stored and managed. The HPLMN is responsible for authenticating the UE (104) and providing access to mobile services. The VPLMN refers to any network that the UE (104) (or subscriber) connects to when they are roaming outside of their HPLMN. This is typically the network of a local operator in a foreign country or region that has a roaming agreement with the subscriber’s home network. The VPLMN provides the UE (104) (or subscriber) with connectivity (e.g., voice calls, data services) while they are visiting or roaming in that area, but the services are billed through the subscriber’s home network.

[0100] Additionally, the first API corresponds to a UE Usage Type (UUT) API. The UE Usage Type (UUT) refers to a parameter that categorizes the UE (104) based on its access permissions and service preferences within the first network. The UE Usage Type (UUT) describes the type of service or the usage characteristics that the UE is allowed to use in a given network. The UUT helps the network determine how the UE (104) should be handled in terms of service availability and access, particularly in the context of 5G and 4G networks. The UUT determines the network technologies(e.g., 4G or 5G) and services that the UE (104) can access. For example, the UUT value indicates that the UE (104) is exclusively authorized to connect to the first network, restricting access to the second network. This is applicable to the UE (104), which is optimized for 5G services in the first network without fallback capabilities. The UUT defines the eligibility of the UE (104) for fallback connectivity in the second network, corresponding to the second network.

[0101] In an embodiment, triggering the first API means the detection unit (222) invokes the UE Usage Type (UUT) API in response to the detected outage or service degradation. The triggering is performed by the detection unit (224) by generating and transmitting an internal request or control signal to a subscriber data management function, such as the UDM or the HSS, indicating the affected HPLMN or VPLMN and requesting an update or activation of UUT-related handling for the impacted UE (104).

[0102] In an embodiment, upon triggering the first API, the transmitting unit (224) is configured to transmit an updated UUT value to a second network entity for the affected HPLMN and the VPLMN. In an aspect, the second network entity may include the MME (212) or the AMF (206). The transmitting unit (224) interacts with the HSS (204) through the interface(s) (206) to update the UUT value. The update ensures that the HSS (204) communicates the new UUT value to downstream components to manage network connectivity effectively during the outage of the first network.

[0103] In an embodiment, the HSS (204) is configured to transmit the updated UUT value in an Update Location Answer (ULA) location update response message to the MME (212). The ULA includes subscriber-related information, such as authentication data, the UE usage type (UUT) values, and allowed network access, enabling efficient network registration and service provisioning. The ULA message ensures that the MME (212) is aware of the updated network conditions, and the MME(212) may make decisions to maintain UE connectivity. The communication between the HSS (214) and the MME (222) is facilitated through standard signaling interfaces as defined in the network architecture (200A). The ULA message carries critical subscriber information, such as authentication details and the UUT value, which is pivotal in determining service continuity during network failures.

[0104] In an embodiment, the control unit (226) is configured to determine, based on the updated UUT value, that the UE (104) is restricted from establishing network connectivity with a second network. The second network may be the 4G network. The determination is performed by evaluating the updated UUT value against one or more predefined access rules or subscription policies stored in the network, where the updated UUT value indicates whether the UE (104) is authorized for internetwork fallback or restricted to access only the first network. When the updated UUT value corresponds to a restriction profile that disallows access to the second network, the control unit (226) identifies the UE (104) as ineligible for fallback and enforces the restriction accordingly. In an example, the updated UUT value includes an access classification indicator specifying network technology eligibility for the UE (104). For instance, a first UUT value may indicate that the UE (104) is authorized to access both the first network and the second network, whereas a second UUT value may indicate that the UE (104) is restricted to access only the first network. When the updated UUT value corresponds to the second UUT value, the control unit (226) determines that the UE (104) is not eligible for fallback to the second network and enforces the restriction accordingly.

[0105] In an embodiment, based on the determination, the control unit (226) is configured to suppress transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, to prevent service fallback of the UE (104) in the second network. The first message is an “Unknown 5GS Subscription” message. The suppression is performed by inhibiting the generation or forwarding of the firstmessage by the UDM (202) toward the AMF (206), or by selectively blocking the delivery of the first message based on the updated UUT value and associated access restriction rules. As a result, the second network entity (AMF (206)) is prevented from initiating fallback-related signaling for the UE (104), thereby avoiding redirection of the UE (104) to the second network. In an example, when the updated UUT value indicates that the UE (104) is restricted to access only the first network, the control unit (226) prevents the from including the “Unknown 5GS Subscription” message in a registration response sent to the AMF (206). Consequently, the AMF (206) does not transmit a fallback-triggering signaling message toward the UE (104), and the UE (104) remains in the first network (5G).

[0106] In an embodiment, if the control unit (226) determines that the UE (104) is permitted to establish the network connectivity with the second network based on the updated UUT value, the control unit (226) is configured to the first message to the second network entity. Upon receiving the first message, the control unit (226) selects a network gateway within the second network based on the updated UUT value to manage the network connectivity of the UE with the second network. In an aspect, the UUT value enables the MME (212) to select an appropriate 4G Packet Gateway (PGW) (210) for eligible UE (104), ensuring seamless fallback to the second network (4G) without service interruptions. In an embodiment, the MME (212) ensures that the selected 4G PGW (210) has sufficient capacity to handle the additional load, preventing network congestion and maintaining high-quality service for the UE (104).

[0107] In an example, the ‘Unknown 5GS Subscription’ message indicate that the AMF (216) cannot locate the necessary subscriber data in the network's subscriber database (228), typically managed by the HSS (204) or the UDM (202). This error code suggests that the UE (104) does not have a valid or registered 5G subscription, and as a result, it cannot be granted access to the 5G Core or 5G services. The AMF (206) then sends the error code to the UE (104). The error code is transmitted when the UE(104) atempts to register with the first network during the outage. The UE (104) initiates a registration process by sending an AMF registration request to the AMF (206) through the Radio Access Network (RAN). The AMF registration request includes the Subscriber Identity Module (SIM) information, such as IMSI (International Mobile Subscriber Identity) or GUTI (Globally Unique Temporary Identifier), which helps the network identify the subscriber. The AMF (206) transmits the error code in an AMF registration response message, instructing the UE (104) to cease connection attempts to the first network, ensuring that the UE (104) does not repeatedly atempt to connect to the first network when it is unavailable, thereby optimizing network resource utilization and avoiding unnecessary signaling traffic. The AMF (206), upon receiving the error code, transmits a service restriction message, such as an “N1 Mode Not Allowed” Non-Access Stratum (NAS) code, to the UE (104), explicitly preventing further connection atempts to the first network (5G). The “N1 Mode Not Allowed error code” indicates that the AMF (206) is rejecting the UE’s attempt to use a specific registration mode (referred to as N1 Mode) due to a policy or configuration issue that prohibits the requested mode in the current context.

[0108] In an embodiment, upon receiving the error code, the UE (104) is configured to transmit a service registration message to the MME (212). The service registration message informs the MME (212) of the intention of the UE (104) to establish connectivity in the fallback network (the second network). The MME (212) utilizes the information provided by the HSS (204) and the updated UUT value to select appropriate resources, such as the Packet Data Network Gateway (PGW) (220), to maintain the connectivity of the UE (104). This step ensures seamless transition and service continuity for the UE (104) during the first network outage.

[0109] In an embodiment, the control unit (226) may be further configured to allocate a time period for the UE (104) to atempt to reconnect to the first network, where the UE (104) transmits a reestablishment connection request to the secondnetwork entity (AMF) to reconnect to the first network on expiration of the allocated time period. For example, the control unit (226) allocates a retry time period of 30 seconds for the UE (104) after detection of the outage in the first network. During the 30-second time period, the UE (104) refrains from initiating fallback registration toward the second network. Upon expiration of the 30-second time period, the UE (104) transmits a reestablishment request message toward the AMF (206), requesting reconnection to the first network. Based on the availability status of the first network at that time, the AMF (206) either allows re-registration in the first network or maintains the restriction on fallback connectivity.

[0110] In an exemplary aspect, the system (108) may configured to detect failure in the first network by degradation in the one or more KPIs. Once failure is detected, the UDM (202) triggers, enabling the UUT API for the affected HPLMN or the VPLMN. After enabling the UUT, the HSS (204) starts sending the updated UUT value in the ULA location update response message as per the HPLMN or the VPLMN. The UDM (202) sends an “Unknown 5GS Subscription” error in the AMF (206) registration response based on the HPLMN or VPLMN. The UDM (202) will not send the error for a subscriber whose profile indicates the NR-only access. Based on the updated UUT value, the MME (212) will select the appropriate 4G PGW (210) to ensure continued service. Based on the “Unknown 5GS Subscription” error in the AMF (206) registration response, the AMF (206) sends an “N1 Mode Not Allowed” message in the NAS code to prevent further connection attempts to the 5GC network.

[0111] Thus, the system (108) ensures network-controlled prevention of undesired service fallback of the UE (104) by dynamically monitoring network conditions, detecting outages in the first network, and managing UE access behavior using updated UE Usage Type (UUT) values. By suppressing unnecessary signaling toward the second network and enabling controlled re-establishment toward the first network, the system (108) maintains compliance with subscriber policies, reducessignaling overhead, avoids repeated connection retries, and preserves core network resources. The system (108) further eliminates the need for manual intervention at the UE side, improves service continuity for eligible subscribers, and enhances overall network stability during outage and recovery scenarios.

[0112] FIG. 3 illustrates an exemplary flow diagram of a method (300) for preventing service fallback of the UE (104) in the network, in accordance with an embodiment of the present disclosure. The method (300) is performed by the system (108). FIG. 3 is explained in conjunction with FIGS. 1, 2A, and 2B.

[0113] At step 302, the UDM PS (provisioning unit (301) detects the service impact or failure detection due to the one or more KPIs degrade in the Home Public Land Mobile Network (HPLMN), or the Visited Public Land Mobile Network (VPLMN) associated with the first network. The provisioning unit (301) analyzes realtime data from components, including the UDM (202), HSS (204), and the AMF (206). This analysis helps identify degraded performance or outages in the first network, triggering necessary corrective actions.

[0114] At step 304, on detecting the service impact, the provisioning unit (301) enables the UUT value corresponding to the service-impacted first network within the HSS (204). The UUT value is updated in the subscriber profile maintained in the database (228) to reflect the fallback eligibility of the UE (104). The provisioning unit (301) communicates with the HSS (204) to ensure that only eligible subscribers with fallback permissions are flagged for redirection to the second network.

[0115] At step 306, the provisioning unit (301) sends the error code corresponding to the service- impacted first network to the UDM (212). The error code, such as “Unknown 5GS Subscription,” is generated to indicate a temporary restriction on 5G connectivity for affected subscribers. The error code is selectively applied basedon subscriber profiles stored in the database (210) to ensure that subscribers restricted to New Radio (NR)-only access are excluded from fallback procedures.

[0116] At step 308, the HSS (204) provides the UUT value in an Update Location Answer (ULA) location update response message to the MME (212).

[0117] At step 310, the UDM (202) sends the “Unknown 5GS Subscription,” error code to the UE (104) by the AMF (206) as part of the AMF registration process for the first network. The error code explicitly informs the UE (104) of its restricted access to the first network and directs the UE (104) to fall back to the second network. This step optimizes network resource utilization by preventing repeated connection attempts by the UE (104) to the first network.

[0118] At step 312, when the AMF (206) detects an issue with the user’s registration or network access, the AMF (206) may respond with the N1 mode not allowed error. The N 1 error code indicates that the UE (104) is not allowed to establish a connection in the first Network due to a failure in the registration process or because the UE (104) subscription does not support 5G access. In such cases, the AMF (206) ensures that no further connection attempts are made on the first network by the UE (104).

[0119] At step 314, upon receiving the error response, the UE (104) transmits a service registration message or a message indicating “next attempt” towards the MME (212) for managing network connectivity in the second network. The MME (212) coordinates the fallback process, ensuring uninterrupted service continuity for eligible subscribers. The fallback mechanism is designed to maintain high-quality service and minimize the impact of the service impact in the first network while adhering to subscriber policies stored in the database (210). Upon receiving the error code, the UE (104) is configured to transmit a service registration message to the MME (212) associated with the second network. The service registration message informsthe MME (212) of the intention of the UE (104) to establish connectivity in the fallback network. The MME (212) utilizes the information provided by the HSS (204) and the updated UUT value to select appropriate resources, such as the 4G PGW (210), to maintain the connectivity of the UE (104). This step ensures seamless transition and service continuity for the UE (104) during the first network outage. Based on the updated UUT value, the MME (222) will select the appropriate 4G PGW (220) to ensure continued service.

[0120] At step 316, the MME (212) uses the updated UUT value to select a PGW (210) in the second network (4G) for eligible subscribers. The MME (212) ensures that the selected PGW (210) has sufficient resources to handle the additional subscriber load, facilitating a seamless transition of data services from the first network to the second network.

[0121] FIG. 4 illustrates another exemplary network architecture (400) with implementation of the system (108) for preventing service fallback of the UE (104) in the network (106), in accordance with an embodiment of the present disclosure. FIG.4 describes the implementation of the system (108), as previously described with reference to FIG. 2B within the network architecture (400).

[0122] The network architecture (400) comprises a Location Management Function (LMF) (438), a Location Services (LCS) Client (440), a Gateway Mobile Location Center (GMLC) (436), a 5G Equipment Identity Register (EIR) (422), the Authentication Server Function (AUSF) (420), the UDM (416), the AMF (410), the RAN (402) (Next Generation Node B (gNB)), UPF (404), the DN (406), the SMF (408), the NEF (412), the PCF (414), the NSSF (428), a Short Message Service Function (SMSF) (434), a Network Data Analytics Function (NWDAF) (432), a Charging Function - Policy Control (CHF-PC) (426), a Signaling Transfer Point (STP) (430), a Diameter Routing Agent (DRA) (424), and a Binding Support Function (BSF) (418).

[0123] In an aspect, the LMF (438) is a core network function responsible for managing the location of the UE (104) to support services (e.g., mobility management, handovers, and location-based services). The LMF (438) tracks and updates the geographical location of the UE (104) (e.g., mobile devices) within the network. The LMF (438) monitors the UE's position as the UE (104) moves across different areas and cells within the network. The LMF (438) supports location-based services (e.g., real-time location sharing, navigation, or emergency services), ensuring that the location of the UE (104) is accurately known and managed.

[0124] In an aspect, the LCS (440) Client refers to a device or application that requests and uses location-based services provided by the network. The LCS (440) client interacts with the network to obtain the geographical location of the UE (104) for various services. The LCS (440) client requests location data from the network, such as the geographical position of the UE (104).

[0125] In one aspect, the GMLC (436) is a network element in the telecommunication network that supports the location-based services (LBS). The GMLC (436) is an interface between the mobile network and external Location-Based Services (LBS) providers (e.g., emergency services, navigation applications, or asset tracking systems). The GMLC (436) handles requests for location information and ensures that the GMLC (436) is securely relayed to the requesting service.

[0126] In an aspect, the 5G EIR (422) is a network element in the telecommunication networks that manages and tracks the identity of mobile devices (UEs) based on their unique identifiers, such as International Mobile Equipment Identity (IMEI) number. The EIR (422) helps ensure network security, prevent fraud, and maintain the integrity of the mobile network.

[0127] In an aspect, the SMSF (434) is a network element responsible for managing and delivering Short Message Service (SMS) messages in the 5Genvironment. The SMSF (434) handles SMS operations to ensure the correct delivery of text messages between users, applications, and networks. The SMSF (434) provides interoperability for SMS across different generations of telecommunication network technologies. The SMSF (434) is responsible for SMS routing, interworking with legacy Short Message Service Centers (SMSCs), session management, and SMS storage when the recipient is unavailable. The SMSF (434) ensures SMS continuity, even for roaming users, and supports SMS over IP, providing a seamless messaging experience in the network.

[0128] In an aspect, the NWDAF (432) is a network element responsible for collecting, analyzing, and providing insights based on network data to optimize network operations, improve performance, and enable data-driven decision-making. The NWDAF (432) performs network management and enhances the network's overall efficiency by supporting key functions (e.g., traffic management, quality of service (QoS), network slice optimization, and predictive maintenance).

[0129] In an aspect, the CHF -PC (426) is a network element used in charging and policy control. The CHF-PC (426) is responsible for enforcing charging rules and ensuring that network services, such as data usage, voice, and SMS, are billed correctly while also applying policy rules that govern how network resources are allocated. The CHF is responsible for handling both the charging and policy control aspects of the network. The CHF-PC (426) ensures that the PCF (414) and the CHF work together to apply consistent and synchronized rules for both quality of service (QoS) and billing.

[0130] In an aspect, the STP (430) is a network element responsible for routing signaling messages, ensuring interoperability between different network elements, and performing functions (e.g., protocol conversion, security, and load balancing). The STP (430) routes signaling between the network functions and provides interoperability with legacy systems. By enabling efficient signaling, the STP (430) ensures seamlessconnectivity, mobility, and communication across different generations of mobile networks.

[0131] In an aspect, the DRA (424) is a network element that routes Diameter signaling messages between network functions, enabling authentication, authorization, accounting, charging, and policy control. Diameter is a protocol used for authentication, authorization, accounting (AAA), and policy control in various network services. The DRA (424) ensures efficient message routing between the network functions and legacy systems, helping to maintain interoperability across network generations and supporting scalable, reliable network operations.

[0132] In an aspect, the BSF (418) is a network element used in the management of user bindings for mobility and session management. The BSF (418) ensures that the user equipment’s identity and context are properly handled as the UEs move across different network slices or access points. The BSF (418) manages user bindings between a user’s identity and their current context regarding mobility, session management, and network access. The BSF (418) supports mobility management, session continuity, and seamless handovers between different network access points or slices by maintaining accurate and up-to-date binding information. The BSF (418) ensures that the network functions (e.g., AMF, SMF, PCF, and UPF), can efficiently handle the user’s session and provide consistent service quality as the user moves across the network.

[0133] An NL7 interface is an interface that enables the communication between the LMF and other location-related functions for location services in an Internet protocol (IP) Multimedia Subsystem (IMS). In an aspect, the IMS is an architecture for delivering multimedia services such as voice, video, messaging, and data over the IP networks.

[0134] A NL1 interface is an interface used between the LMF (438) and the AMF (410). The NL1 manages user mobility and authentication during the registration and handover processes. The NL1 interface allows the LMF (438) and the AMF (410) to handle location and mobility management and ensures a smooth user experience as the user equipment (UE) moves through the network and maintains its active session.

[0135] A NL2 interface is a communication interface between the GMLC (436) and the AMF (410) in the network to support the location-based services (LBS) to provide location information for emergency services, tracking, and other locationdependent services. The NL2 interface ensures a smooth user experience during mobility events, maintains consistent session quality, and efficiently manages the network’s resources as users move through different cells or network slices.

[0136] A NL6 interface is an interface between the GMLC (436) and the UDM (416) used to communicate the location data when location-based services or subscriber-related information is required for delivering accurate location data. The NL6 interface allows the GMLC (436) to query the UDM (416) to validate the subscriber and ensure they are authorized for the requested location service.

[0137] A NL17 interface is an interface between the EIR (422) and the AMF (410) for managing the security and integrity of the user equipment (UE) attempting to access the network. The NL17 interface helps in maintaining network security by facilitating communication between the EIR (422) and the AMF (410) to authenticate devices, ensuring that only authorized and non-compromised UEs can access the network.

[0138] A N12 interface is an interface between the AUSF, and the AMF (410) used for the authentication and security procedures during the initial registration and mobility management of the user equipment (UE) in the network. The N12 interfacehelps ensure a robust and secure network by coordinating the authentication procedure and providing a secure mechanism for validating user identity.

[0139] A N13 interface is an interface between the AUSF and the UDM (416) used for the authentication process of the user equipment (UE) and ensures that the UE trying to connect to the network is legitimate and authorized to access services. The N13 interface supports the AUSF in retrieving authentication data necessary for verifying the identity of the UE from the UDM (416) to ensure the secure and authenticated access to the network.

[0140] A N8 interface is an interface between the UDM (416) and the AMF responsible for supporting network procedures (e.g., subscriber management, authentication, and service access). The N8 interface facilitates communication between the AMF (410) and the UDM (416) to retrieve or update the subscriber's profile during registration, authentication, or mobility management procedures.

[0141] A N14 interface is an interface used by the AMF (410) for coordinating session management and mobility management, enabling these two core network functions to work together in supporting the user's session, particularly during handovers or mobility events. The N14 interface facilitates the exchange of information required for session management, mobility management, and bearer resource management. It ensures that user sessions are maintained without interruption, even as the user moves across different areas of the network.

[0142] A N16 interface is an interface used by the SMF (408) for service data flow (SDF) management. The N16 interface is responsible for the interaction between the SMF (408) and the application functions (AFs), such as service platforms or applications that require session management and data flow control. The N16 interface communication ensures that user sessions are optimized for the specific needs of each service, leading to a more tailored and efficient user experience.

[0143] A Nil interface is an interface between the AMF (410) and the SMF (408) for managing session establishment, modification, and termination, as well as handling mobility management and user authentication across the network. The Nil interface allows the AMF (410) to manage the UE’s mobility, ensure correct bearer allocation, and communicate with the SMF (408) for session-related activities (e.g., session establishment, modification, and release).

[0144] A N10 interface is an interface between the UDM (416) and the SMF (408) for managing subscription data and session information related to user services, such as retrieving subscriber profiles and policy information and ensuring that the session is established and maintained according to the subscriber's preferences and network policies. The N10 interface facilitates the exchange of subscriber profile information between the SMF (408) and the UDM (416).

[0145] A N15 interface is an interface between the PCF (414) and the AMF responsible for enabling the AMF (410) to interact with the PCF (414) for policy control and decision-making related to mobility management and session management for the user equipment (UE). The N15 interface helps the AMF (410), and the PCF (414) to enforce the QoS policies and ensure that the appropriate policies are applied to the users' sessions based on their behavior, subscription, and network conditions.

[0146] A N22 interface is an interface between the AMF (410) and the NSSF (428) that enables the AMF (410) to interact with the NSSF (428) to obtain information about network slice selection for a particular user equipment or session. This interaction ensures that the appropriate network slice is selected for the user equipment based on subscription, service requirements, and network conditions.

[0147] A N21 interface is an interface between the UDM (416) and the SMSF (434) that enables the SMSF (434) to interact with the UDM (416) to manage Short Message Service (SMS) functionality, particularly for storing, retrieving, andprocessing subscriber-related data and settings related to SMS services. The N21 interface enables the SMSF (434) to access and manage subscriber information related to SMS services. Through the N21 interface, the SMSF (434) can retrieve the necessary subscriber profiles, manage SMS service activation and deactivation, handle message routing, and ensure that SMS services are properly authorized and authenticated.

[0148] A N20 interface is an interface between the SMSF (434) and the AMF (410) for effective management of SMS services. The N20 interface facilitates the exchange of information related to SMS delivery, mobility management, and session management. Through the N20 interface, the AMF (410) and the SMSF (434) ensure that SMS messages are delivered correctly, even when the UE is moving between cells or undergoing other mobility events. The N20 interface helps maintain the integrity of SMS services by ensuring that mobility context, delivery status, and subscriber preferences are communicated between the two functions to provide seamless SMS service.

[0149] A N23 interface is an interface between the PCF (414) and the NWDAF (432), enabling the PCF (414) to incorporate real-time network data and analytics into its policy control decisions. The N23 interface allows the PCF (414) to request and receive network data from the NWDAF (432) to inform its policy decisions. By leveraging insights provided by the NWDAF (432), the PCF (414) can dynamically adjust policies to optimize network performance, service quality, and resource utilization. The N23 interface helps ensure that policies are context-aware and responsive to changing network conditions, enhancing overall user experience and network efficiency.

[0150] A N34 interface is an interface between the NWDAF (432) and the NSSF (428) that facilitates the exchange of data related to network slicing and network performance analytics. By providing detailed network analytics (including slice performance, traffic forecasting, and load balancing data), the NWDAF (432) ensuresthat the NSSF (428) can select an appropriate network slice for each UE or network service.

[0151] A N40 interface is an interface between the SMF (408) and the CHF-PC (426) for enabling accurate charging and policy enforcement in the network. The N40 allows for the real-time exchange of charging data, policy control decisions, and service usage reports. By using the N40 interface, the SMF (408) and the CHF -PC (426) work together to ensure that users are billed appropriately for their network usage and that network policies are adhered to during the lifecycle of a user session.

[0152] A N28 interface is an interface between the PCF (414) and the CHF-PC (426) that facilitates the exchange of charging and policy control information, ensuring that policy decisions made by the PCF (414) are aligned with charging rules managed by the CHF-PC (426). The N28 interface facilitates the exchange of charging data and real-time updates, ensures that users are billed correctly for the services consumed, and that quality of service (QoS) levels are maintained across the network.

[0153] A N52 interface is an interface between the UDM (416) and the NEF (412) that enables the UDM (416) to expose relevant subscriber data and authentication information to other network functions or external applications via the NEF (412). The N52 interface is used for providing subscriber-related data (e.g., authentication details, subscription information, and other user-related data) to third-party services or applications that require such data for certain functionalities (e.g., network slicing, quality of service enforcement, or policy decisions).

[0154] A N29 interface is an interface between the SMF (408) and the NEF (412) for providing session-related information and policy decisions from the SMF (408) to external network entities and third-party applications via the NEF (412). A N29 interface is also an interface between the NEF (412) and the BSF (418) used for binding and authentication purposes, facilitating the interaction between the NEF (412)and the BSF (418) to expose relevant binding and user context information to third-party services or applications securely. The N29 interface is useful in location-based services, mobility management, authentication or authorization of external applications, and network slice management.

[0155] A N51 interface is an interface between the AMF (410) and the NEF (412) that enables the AMF (410) to expose mobility management and authentication data to external applications or services via the NEF (412). The N51 interface supports location-based services, authentication services, network slice management, and policy enforcement. By facilitating the secure and controlled exposure of mobility data, authentication context, and policy information, the N51 interface enables third-party applications to interact with the network.

[0156] A SGd interface is an interface between the SMSF (434) and the DRA (424) that supports SMS routing, message delivery, and policy enforcement within the network. By using Diameter signaling, the SGd interface allows the SMSF (434) to interact with the DRA (424) for functions (e.g., user profile retrieval, SMS routing decisions, charging, and accounting). The SGd interface enables the network to deliver SMS services efficiently and securely, ensuring correct message routing, billing, and policy enforcement.

[0157] A signaling transport (SIGTRAN) interface / protocol is an interface between the SMSF (434) and the STP (430) for facilitating signaling related to the Short Message Service (SMS) within the network and for routing and transferring SMS-related signaling messages across different parts of the network and the SS7 networks. The SIGTRAN facilitates the routing of SMS messages, user profile handling, delivery confirmation, and charging through Diameter and SS7-based signaling adapted for IP transport.

[0158] A Gy, Sy interface is a signaling interface used between the CHF -PC (426) and the DRA (424) for managing charging and policy control operations related to user sessions and data flows. The Gy, Sy interface ensures that Diameter signaling for charging, policy enforcement, and QoS is efficiently routed between the CHF -PC (426) and other network components (e.g., policy and Charging Rules Function (PCRF), home subscriber server (HSS) (214), and billing systems. By handling the interactions between the CHF -PC (426) and the DRA (424), the Gy, Sy interface enables the effective application of charging rules and policy enforcement in the network.

[0159] In an aspect, a Sd interface is an interface between the PCF (414) and the DRA (424) responsible for ensuring that policy decisions made by the PCF (414) are properly enforced and charging information is accurately routed and exchanged between various network components (e.g., PCRF, CHF (Charging Function), and billing systems).

[0160] In an aspect, an Rx interface is an interface between the PCF (414) and the BSF (418) for managing policy control and binding information related to user data sessions and mobility management. The Rx interface enables the PCF (414) to access and utilize binding information provided by the BSF (418) for efficient policy enforcement. Also, a Rx interface is an interface between the DRA (424) and the BSF (418) for the Diameter-based signaling in the network. The Rx interface ensures that charging rules and quality of service (QoS) policies are applied consistently and accurately to user sessions by enabling the necessary information exchange between the DRA (424) and the BSF (418).

[0161] In an embodiment, the procedure for NWD AF registration initiates with the UDM (416) using a PUT request. In an aspect, the NWDAF (432) sends a registration request containing the Subscription Permanent Identifier (SUPI), NWDAF registration identity, and other registration information to the UDM (416). The UDM(416) either accepts the request with a "200 OK" or "201 Created" response or rejects it with a "403 Forbidden" response when subscription data or authorization is missing. Based on the response, the registration may be successfully created or rejected due to missing subscription data or authorization failures.

[0162] Unlike conventional methods that rely on static fallback rules or UE-initiated actions, by implementing the system (108), the network architecture (400) enables the network to intelligently decide whether a UE should remain on the first network or be transitioned to a second network, such as from 5Gto 4G, without manual intervention at the UE. For example, the system (108) continuously monitors the one or more key performance parameters to proactively identify service degradation or outages in the first network. Upon detection, the system (108) dynamically controls network behavior by updating the user equipment usage type (UUT) values and selectively applying standardized error codes and registration controls. As a result, the network architecture (400) ensures policy-compliant service continuity, reduces unnecessary reconnection attempts, and improves adaptability to dynamic network conditions.

[0163] FIG. 5 illustrates an exemplary method (500) flow for preventing service fallback of the UE (104) in the network (106), in accordance with an embodiment of the present disclosure. FIG. 5 is described with reference to FIG. 2B

[0164] At step 502, the method (500) includes monitoring, by the first network entity, one or more network performance parameters in a first network serving the UE (104). In an aspect, the first network entity may include the UDM and the HSS. In an example, the first network is the 5G network.

[0165] At step 504, the method (500) includes detecting, by the first network entity, the outage in the first network based on the monitored one or more performance parameters.

[0166] At step 506, the method (500) includes triggering, by the first network entity, the first API for the affected at least the HPLMN and the VPLMN in response to the detected outage in the first network.

[0167] At step 508, the method (500) includes transmitting, by the first network entity, the updated User Equipment Usage Type (UUT) value to the second network entity for the affected HPLMN and the VPLMN upon triggering the first API. In an aspect, the second network entity may include the MME and the AMF.

[0168] At step 510, the method (500) includes determining, by the first network entity, based on the updated UUT value, that the UE (104) is restricted to establish the network connectivity with the second network. In an example, the second network is the 4G network.

[0169] At step 512, the method (500) includes suppressing, by the first network entity, transmission of the first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE (104) in the second network. In an aspect, the first message is the Unknown 5GS Subscription message.

[0170] In an aspect, the method further includes determining, by the first network entity, that the UE is permitted to establish the network connectivity with the second network based on the updated UUT value and transmitting, by the first network entity, the first message to the second network entity. In an aspect, upon receiving the first message, the second network entity selects a network gateway within the second network based on the updated UUT value to manage the network connectivity of the UE (104) with the second network.

[0171] In an aspect, the method further includes allocating, by the first network entity, the time period for the UE (104) to attempt to reconnect to the first network, where the UE (104) transmits the reestablishment connection request to the secondnetwork entity to reconnect to the first network on expiration of the allocated time period.

[0172] In an embodiment, a system for preventing service fallback of a user equipment (UE) in a network is described. The system includes a monitoring unit, a detection unit, a transmitting unit, and a control unit at a first network entity. The monitoring unit, the detection unit, the transmitting unit, and the control unit are communicable coupled to operatively coupled with one another. The monitoring unit is configured to monitor one or more network performance parameters in a first network serving the UE. The detection unit is configured to detect an outage in the first network based on the monitored one or more performance parameters. The detection unit is further configured to trigger a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network. The transmitting unit is configured to transmit an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API. The control unit is configured to determine based on the updated UUT value, that the UE is restricted to establish a network connectivity with a second network and suppress transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE in the second network.

[0173] In an exemplary embodiment, user equipment (UE) for preventing service fallback in a network, the UE includes a memory and a processor communicably coupled to the memory, where the processor is configured to transmit, to a system, a request to monitor one or more performance parameters to detect an outage in a first network, and receive from the system, a response associated with the request. The response is received based on monitoring, by the system, the one or more performance parameters in the first network serving the UE, detecting, by the system,the outage in the first network based on the monitored one or more performance parameters, triggering, by the system, a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network, transmitting, by the system, an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API, determining, by the system, based on the updated UUT value, that the UE is restricted to establish a network connectivity with a second network and suppressing, by the system, transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE in the second network.

[0174] FIG. 6 illustrates an example computer system 600 in which or with which the embodiments of the present disclosure may be implemented.

[0175] As shown in FIG. 6, the computer system 600 may include an external storage device 610, a bus 620, a main memory 630, a read-only memory 640, a mass storage device 650, a communication port(s) 660, and a processor 670. A person skilled in the art will appreciate that the computer system 600 may include more than one processor and communication ports. The processor 670 may include various modules associated with embodiments of the present disclosure. The communication port(s) 660 may be any of an RS-232 port for use with a modem-based dialup connection, a 10 / 100 Ethernet port, a Gigabit or 10 Gigabit port using copper or fiber, a serial port, a parallel port, or other existing or future ports. The communication ports(s) 660 may be chosen depending on a network, such as a Local Area Network (LAN), Wide Area Network (WAN), or any network to which the computer system 600 connects.

[0176] In an embodiment, the main memory 630 may be Random Access Memory (RAM), or any other dynamic storage device commonly known in the art. The read-only memory 640 may be any static storage device(s) e.g., but not limited to, aProgrammable Read Only Memory (PROM) chip for storing static information e.g., start-up or basic input / output system (BIOS) instructions for the processor 670. The mass storage device 650 may be any current or future mass storage solution, which can be used to store information and / or instructions. Exemplary mass storage solutions include, but are not limited to, Parallel Advanced Technology Attachment (PAT A) or Serial Advanced Technology Attachment (SATA) hard disk drives or solid-state drives (internal or external, e.g., having Universal Serial Bus (USB) and / or Firewire interfaces).

[0177] In an embodiment, the bus 620 may communicatively couple the processor(s) 670 with the other memory, storage, and communication blocks. The bus 620 may be, e.g. a Peripheral Component Interconnect PCI) / PCI Extended (PCI-X) bus, Small Computer System Interface (SCSI), Universal Serial Bus (USB), or the like, for connecting expansion cards, drives, and other subsystems as well as other buses, such a front side bus (FSB), which connects the processor 670 to the computer system 600.

[0178] In another embodiment, operator, and administrative interfaces, e.g., a display, keyboard, and cursor control device may also be coupled to the bus 620 to support direct operator interaction with the computer system 600. Other operator and administrative interfaces can be provided through network connections connected through the communication port(s) 660. Components described above are meant only to exemplify various possibilities. In no way should the aforementioned exemplary computer system 600 limit the scope of the present disclosure.

[0179] In an exemplary embodiment, user equipment (UE) for preventing service fallback in a network, the UE includes a memory and a processor communicably coupled to the memory, where the processor is configured to transmit, to a system, a request to monitor one or more performance parameters to detect an outage in a first network, and receive from the system, a response associated with therequest. The response is received based on monitoring, by the system, the one or more performance parameters in the first network serving the UE, detecting, by the system, the outage in the first network based on the monitored one or more performance parameters, triggering, by the system, a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network, transmitting, by the system, an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API, determining, by the system, based on the updated UUT value, that the UE is restricted to establish a network connectivity with a second network and suppressing, by the system, transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE in the second network.

[0180] The present disclosure offers significant technical advancements by optimizing network signaling and access control during network outage conditions. By dynamically monitoring key performance indicators and managing UE Usage Type (UUT) values at the core network level, the system ensures that service fallback behavior is controlled in a network-driven manner. This approach prevents unnecessary signaling toward secondary networks, reduces repeated registration and session establishment attempts, and avoids congestion and resource exhaustion in both the first network and the second network during service degradation scenarios.

[0181] The present disclosure enables seamless handling of outage and recovery scenarios without requiring manual intervention at the UE side, thereby improving service continuity, network stability, and efficient utilization of core network resources.

[0182] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing fromthe basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

[0183] The method and system of the present disclosure may be implemented in a number of ways. For example, the methods and systems of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above unless specifically stated otherwise. Further, in some embodiments, the present disclosure may also be embodied as programs recorded in a recording medium, the programs including machine-readable instructions for implementing the methods according to the present disclosure. Thus, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0184] While considerable emphasis has been placed herein on the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be implemented merely as illustrative of the disclosure and not as a limitation.TECHNICAL ADVANTAGES

[0185] The present disclosure described herein above has several technical advantages including, but not limited to, the realization of the system and the method that:

[0186] The present disclosure provides a method that ensures that users with profiles restricted to a first network are not redirected to a second network, thereby maintaining compliance with the subscription policies of the users and avoiding unnecessary disruptions;

[0187] The present disclosure provides a method that reduces connection retry attempts and restricts access to the first network during outage conditions, thereby minimizing network congestion and preserving network resources for unaffected subscribers.

[0188] The present disclosure provides a method that facilitates a smooth transition of eligible subscribers from the first network to the second network by dynamically updating User Equipment Usage Type (UUT) values and selecting appropriate packet gateway entities associated with the second network.

[0189] The present disclosure provides a method that enables prompt detection of failures in the first network and selectively triggers fallback mechanisms, thereby ensuring uninterrupted service continuity for eligible subscribers and improving overall user experience.

[0190] The present disclosure provides a method that eliminates the need for manual intervention at a User Equipment (UE) when an outage is detected in the first network, thereby simplifying mobility handling and reducing user dependency.

[0191] The present disclosure provides a method that prevents unnecessary rejection responses from a core network for subscribers restricted to fifth-generation(5G)-only access, thereby ensuring seamless and policy-compliant handling of restricted subscriber scenarios.

Claims

We Claim1. A method (500) for preventing service fallback of a user equipment (UE) (104) in a network (106), the method (500) comprising:monitoring (502), by a first network entity, one or more network performance parameters in a first network serving the UE (104);detecting (504), by the first network entity, an outage in the first network based on the monitored one or more performance parameters;triggering (506), by the first network entity, a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network;transmitting (508), by the first network entity, an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API;determining (510), by the first network entity, based on the updated UUT value, that the UE (104) is restricted to establish a network connectivity with a second network; andsuppressing (512), by the first network entity, transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE (104) in the second network.

2. The method (500) as claimed in claim 1, further comprising:determining, by the first network entity, that the UE (104) is permitted to establish the network connectivity with the second network based on the updated UUT value; andtransmitting, by the first network entity, the first message to the second network entity.

3. The method (500) as claimed in claim 2, wherein upon receiving the first message, the second network entity selects a network gateway within the second network based on the updated UUT value to manage the network connectivity of the UE (104) with the second network.

4. The method (500) as claimed in claim 1, further comprising:allocating, by the first network entity, a time period for the UE (104) to attempt to reconnect to the first network, wherein the UE (104) transmits a reestablishment connection request to the second network entity to reconnect to the first network on expiration of the allocated time period.

5. The method (500) as claimed in claim 1, wherein the first message is an “Unknown 5GS Subscription” message.

6. The method (500) as claimed in claim 1, wherein the first network is a fifth generation (5G) network and the second network is a fourth generation (4G) network.

7. A system (108) for preventing service fallback of a user equipment (UE) (104) in a network, the system (108) comprising:a monitoring unit (220), a detection unit (222), a transmitting unit (224), and a control unit (226) at a first network entity, wherein the monitoring unit(220), the detection unit (222), the transmitting unit (224), and the control unit (226) are communicably coupled to with one another;wherein the monitoring unit (220) is configured to monitor one or more network performance parameters in a first network serving the UE (104);wherein the detection unit (222) is configured to:detect an outage in the first network based on the monitored one or more performance parameters;trigger a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network;wherein the transmitting unit (224) is configured to transmit an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API;wherein the control unit (226) is configured to:determine based on the updated UUT value, that the UE (104) is restricted to establish a network connectivity with a second network; andsuppress transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE (104) in the second network.

8. The system (108) as claimed in claim 7, wherein the control unit (226) is further configured to:determine that the UE (104) is permitted to establish the network connectivity with the second network based on the updated UUT value; andtransmit the first message to the second network entity.

9. The system (108) as claimed in claim 7, wherein upon receiving the first message, the second network entity selects a network gateway within the second network based on the updated UUT value to manage the network connectivity of the UE (104) with the second network.

10. The system (108) as claimed in claim 7, wherein the control unit (226) is further configured to:allocate a time period for the UE (104) to attempt to reconnect to the first network, wherein the UE (104) transmits a reestablishment connection request to the second network entity to reconnect to the first network on expiration of the allocated time period.

11. The system (108) as claimed in claim 7, wherein the first message is an “Unknown 5GS Subscription” message.

12. The system (108) as claimed in claim 7, wherein the first network is a fifth generation (5G) network, and the second network is a fourth generation (4G) network.

13. A user equipment (UE) (104) for preventing service fallback in a network, the UE (104) comprising:a memory; anda processor communicably coupled to the memory, wherein the processor is configured to:transmit, to a system (108), a request to monitor one or more performance parameters to detect an outage in a first network,and receive from the system (108), a response associated with the request wherein the response is received based on:monitoring, by the system (108), the one or more performance parameters in the first network serving the UE (104);detecting, by the system (108), the outage in the first network based on the monitored one or more performance parameters;triggering, by the system (108), a first application programming interface (API) for an affected at least a Home Public Land Mobile Network (HPLMN) and a Visited Public Land Mobile Network (VPLMN) in response to the detected outage in the first network;transmitting, by the system (108), an updated User Equipment Usage Type (UUT) value to a second network entity for the affected HPLMN and the VPLMN upon triggering the first API;determining, by the system (108), based on the updated UUT value that the UE (104) is restricted to establish a network connectivity with a second network; andsuppressing, by the system (108), transmission of a first message in the second network entity for the affected HPLMN and the VPLMN, based on the determination, for preventing service fallback of the UE (104) in the second network.

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