FORM 2
THE PATENTS ACT, 1970 (39 OF 1970) & THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“METHOD AND SYSTEM FOR PERFORMING NETWORK REGISTRATION IN A WIRELESS COMMUNICATION
NETWORK”
We, Jio Platforms Limited, an Indian National, of Office - 101, Saffron, Nr. Centre Point, Panchwati 5 Rasta, Ambawadi, Ahmedabad - 380006, Gujarat, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

5 METHOD AND SYSTEM FOR PERFORMING NETWORK
REGISTRATION IN A WIRELESS COMMUNICATION NETWORK
FIELD OF THE DISCLOSURE
10 The present disclosure relates generally to the field of network registration. More particularly, the present invention relates to method and system for configurable error mapping for network registration in a wireless communication system.
BACKGROUND
15
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
20 enhance the understanding of the reader with respect to the present disclosure, and not as admissions of prior art.
In existing systems, one of the significant issues that exists is the prolonged periods during which devices remain deregistered after receiving registration rejection
25 messages from the 5G network. This occurs due to the lack of proper mechanisms to handle registration failures for 4G only SIMs in 5G networks. As a result of prolonged deregistration periods, users experience disrupted connectivity, leading to a poor user experience. Devices (such as User Equipment(s)) are unable to perform a quick transition to a compatible network (such as 4G) after being rejected
30 by the 5G network, resulting in a loss of network access and service disruptions. The existing method or system often lacks clarity in the reasons for registration rejection, making it difficult for devices to understand the cause of the failure and take appropriate corrective actions. This lack of transparency further exacerbates the issue of prolonged deregistration. The inability of devices to quickly switch
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5 between networks following a registration rejection leads to inefficient utilization of network resources. This inefficiency can strain network capacity and impact overall network performance. In some cases, the existing method and systems may not adequately address security concerns during the registration process, particularly when authenticating the identity of devices attempting to connect to the
10 network. This can pose risks to network integrity and user privacy.
Therefore, in light of the foregoing discussion, there exists a need for an improved method and system that can effectively handle the registration of 4G only SIMs in 5G networks, ensuring seamless connectivity, efficient network resource 15 utilization, and enhanced security, without causing prolonged deregistration periods and ensuring continuous connectivity for the users.
OBJECTS OF THE INVENTION
20 Some of the objects of the present disclosure, which at least one embodiment disclosed herein satisfies are listed herein below.
It is an object of the present invention to provide a system and method configurable error mapping for network registration in a wireless communication system.
25
It is another object of the present invention to provide a system and method configurable error mapping for network registration in a wireless communication system that prevent devices with 4G only SIMs from remaining in a deregistered state for an extended period when they receive rejections from the 5G network due
30 to the absence of user data provisioning in the 5G Authentication Server Function/User Data Management (AUSF/UDM). This aims to ensure that the device or user equipment (UE) can quickly attempt to connect to a 4G network instead of waiting for long durations.
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5 It is yet another object of the present invention to provide a system and method configurable error mapping for network registration in a wireless communication system that ensure seamless connectivity for users by enabling devices to swiftly transition to a 4G network in the event of a registration rejection from the 5G network. This is particularly important for users who rely on continuous network
10 access for their communication and data needs.
It is yet another object of the present invention to provide a system and method configurable error mapping for network registration in a wireless communication system that provides flexibility in mapping HTTP error codes received from the 15 AUSF/UDM to specific NAS (Non-Access Stratum) cause codes. This flexibility allows the network to dynamically adjust its response based on different scenarios and error codes, thereby enhancing the adaptability of the network to various registration challenges.
20 It is yet another object of the present invention to provide a system and method configurable error mapping for network registration in a wireless communication system that by reducing the time that devices spend in a deregistered state, the invention aims to enhance the overall efficiency and performance of the network. This can lead to improved network resource management and a better allocation of
25 network capacity to active users.
It is yet another object of the present invention to provide a system and method configurable error mapping for network registration in a wireless communication system that intends to improve the user experience by minimizing disruptions in 30 connectivity. By ensuring that devices can quickly reconnect to the network after a registration rejection, users can enjoy uninterrupted access to network services, leading to higher satisfaction and a better overall experience.
4

5 It is yet another object of the present invention to provide a system and method configurable error mapping for network registration in a wireless communication system that aims to facilitate a smooth transition for users moving between 4G and 5G networks. By providing a mechanism that allows devices to quickly adapt to the appropriate network based on their capabilities and the available infrastructure, the
10 invention ensures that users can seamlessly access the best possible network without facing prolonged connectivity issues.
SUMMARY
15 This section is provided to introduce certain aspects of the present disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
20 The present disclosure relates generally to the field of wireless communication systems. More particularly, the present disclosure relates to network registration management and error handling. More particularly, the present invention relates to method and system for configurable error mapping for network registration in a wireless communication system.
25
According to an aspect of the present disclosure, a method implemented by a network node for network registration in a wireless communication network is disclosed. The method includes receiving, at the network node from a user equipment (UE), a registration request for establishment of a connection between
30 the UE and a first network. Next, the method includes authenticating, by the network node, an identity of the UE based on a communication with an authentication network node for the received registration request. Next, the method includes receiving, at the network node, a registration reject message from the authentication network node based on a failure of the authentication of the identity
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5 of the UE. Next, the method includes mapping, by the network node, the registration reject message with a plurality of error codes to identify an error cause code. Thereafter, the method includes transmitting, by the network node, the registration reject message to the UE along with the identified error cause code.
10 In an exemplary aspect of the present disclosure, the network node is an Access and Mobility Management Function (AMF) associated with the first network, wherein the first network is a 5th Generation (5G) Network.
In an exemplary aspect of the present disclosure, the authentication network node 15 corresponds to an Authentication Server Function (AUSF) associated with the first network.
In an exemplary aspect of the present disclosure, the registration reject message comprises at least one of a plurality of HTTP error cause codes. 20
In an exemplary aspect of the present disclosure, the plurality of error codes corresponds to Non-Access Stratum (NAS) cause codes associated with the registration reject message.
25 In an exemplary aspect of the present disclosure, the error cause code corresponds to non-allowance of N1 mode by the first network.
In an exemplary aspect of the present disclosure, the registration request is received from the UE enabled with a subscriber identity module (SIM) configured to operate 30 on a second network.
In an exemplary aspect of the present disclosure, the transmission of the registration reject message to the UE along with the identified error cause code indicates the
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5 UE to disable N1 mode and attempt to establish a connection with the second network, wherein the second Network is a 4th Generation (4G) network.
In an exemplary aspect of the present disclosure, the registration request is received from the UE enabled with a subscriber identity module (SIM) which is configured 10 to operate on a second network.
In an exemplary aspect of the present disclosure, wherein the transmission of the registration reject message to the UE along with the identified error cause code indicates the UE to disable N1 mode and attempt to establish a connection with the 15 second network.
According to another aspect of the present disclosure, a network node for configurable error mapping for network registration in a wireless communication system is disclosed. The network node includes: a receiving unit configured to
20 receive, from a user equipment (UE), a registration request for establishment of a connection between the UE and a first network. Next, an authentication unit configured to authenticate an identity of the UE based on a communication with an authentication network node for the received registration request. Next, the receiving unit configured to receive a registration reject message from the
25 authentication network node based on a failure of the authentication of the identity of the UE. Next, a mapping unit configured to map the registration reject message with a plurality of error codes to identify a corresponding error cause code, and a transmitting unit configured to transmit the registration reject message to the UE along with the identified error cause code.
30
According to yet another aspect of the present disclosure, a non-transitory computer-readable storage medium storing instruction, the storage medium comprising executable code which, when executed by one or more units of a system, causes: a receiving unit to receive, from a user equipment (UE), a
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5 registration request for establishment of a connection between the UE and a first network; an authentication unit to authenticate an identity of the UE based on a communication with an authentication network node for the received registration request; the receiving unit to receive a registration reject message from the authentication network node based on a failure of the authentication of the identity
10 of the UE; a mapping unit to map the registration reject message with a plurality of error codes to identify a corresponding error cause code; and a transmitting unit to transmit the registration reject message to the UE along with the identified error cause code.
15 BRIEF DESCRIPTION OF DRAWINGS
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,
20 emphasis 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
25 implement such components.
FIG. 1 illustrates an exemplary block diagram representation of 5th generation core (5GC) network architecture, in accordance with exemplary embodiment of the present disclosure. 30
FIG. 2 illustrates an exemplary block diagram of a system, in accordance with exemplary embodiments of the present disclosure.
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5 FIG. 3 illustrates an exemplary sequence diagram indicating the process of mapping HTTP error cause code to NAS cause code, in accordance with exemplary embodiments of the present disclosure.
FIG. 4 illustrates another exemplary method flow diagram indicating the process 10 for network registration in a wireless communication network, in accordance with exemplary embodiments of the present disclosure.
Fig. 5 illustrates an exemplary block diagram of a computing device upon which an embodiment of the present disclosure may be implemented. 15
The foregoing shall be more apparent from the following more detailed description of the disclosure.
DESCRIPTION
20
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
25 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
30 are described below, as illustrated in various drawings in which like reference numerals refer to the same parts throughout the different drawings.
The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the
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5 ensuing description of the exemplary embodiments will provide those skilled in the art 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.
10
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
15 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.
20 Also, it is noted that individual embodiments may be described as a process which 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
25 is terminated when its operations are completed but could have additional steps not included in a figure.
In addition, each block may indicate some of modules, segments, or codes including one or more executable instructions for executing a specific logical function(s). 30 Further, functions mentioned in the blocks occur regardless of a sequence in some alternative embodiments. For example, two blocks that are contiguously illustrated may be simultaneously performed in fact or be performed in a reverse sequence depending on corresponding functions.
10

5 Herein, the term "unit" indicates software or hardware components, such as a field-programmable gate array (FPGA) and an application-specific integrated circuit (ASIC). However, the meaning of the "unit" is not limited to software or hardware. For example, a "unit" may be configured to be in a storage medium that may be addressed and may also be configured to be reproduced one or more processor.
10 Accordingly, a "unit" may include components such as software components, object-oriented software components, class components, and task components and processors, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuit, data, database, data structures, tables, arrays, and variables. The functions provided in the components and the "units"
15 may be combined with a smaller number of components, and the "units" or may be further separated into additional components and "units". In addition, the components and the "units" may also be implemented to reproduce one or more central processing units (CPUs) within a device or a security multimedia card.
20 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
25 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 in a manner similar to the term “comprising” as an open transition word without precluding any additional or other
30 elements.
As used herein, an “electronic device”, or “portable electronic device”, or “user device” or “communication device” or “user equipment” or “device” refers to any electrical, electronic, electromechanical and computing device. The user device is
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5 capable of receiving and/or transmitting one or parameters, performing function/s, communicating with other devices. The user equipment may have a processor, a display, a memory, a battery and an input-means such as a hard keypad and/or a soft keypad. The user equipment may be capable of operating on any radio access technology including but not limited to IP-enabled communication, Zig Bee,
10 Bluetooth, Bluetooth Low Energy, Near Field Communication, Z-Wave, Wi-Fi, Wi-Fi direct, etc. For instance, the user equipment may include, but not limited to, a mobile phone, smartphone, virtual reality (VR) devices, augmented reality (AR) devices, laptop, a general-purpose computer, desktop, personal digital assistant, tablet computer, mainframe computer, or any other device as may be obvious to a
15 person skilled in the art for implementation of the features of the present disclosure.
Further, the user device may also comprise a “processor” or “processing unit” includes processing unit, wherein processor refers to any logic circuitry for processing instructions. The processor may be a general-purpose processor, a
20 special purpose processor, a conventional processor, a digital signal processor, a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits, Field Programmable Gate Array circuits, any other type of integrated circuits, etc. The processor may perform signal coding data processing, input/output processing,
25 and/or any other functionality that enables the working of the system according to the present disclosure. More specifically, the processor is a hardware processor.
As portable electronic devices and wireless technologies continue to improve and grow in popularity, the advancing wireless technologies for data transfer are also 30 expected to evolve and replace the older generations of technologies. In the field of wireless data communications, the dynamic advancement of various generations of cellular technology are also seen. The development, in this respect, has been incremental in the order of second generation (2G), third generation (3G), fourth
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5 generation (4G), and now fifth generation (5G), and more such generations are expected to continue in the forthcoming time.
Hereinafter, terms identifying an access node, terms indicating network entities, terms indicating messages, terms indicating an interface between network entities, 10 and terms indicating various pieces of identification information, as used in the following description, are exemplified for convenience of explanation. Accordingly, the disclosure is not limited to terms to be described below, and other terms indicating objects having equal technical meanings may be used.
15 In the following descriptions, the term "base station" refers to an entity for allocating resources to a user equipment (UE) and may be used interchangeably with at least one of a gNode B, an eNode B, a node B, a base station (BS), a radio access unit, a radio access network (RAN), a base station controller (BSC), or a node over a network. The term "terminal" may be used interchangeably with a user
20 equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions. However, the disclosure is not limited to the aforementioned examples.
Radio Access Technology (RAT) refers to the technology used by mobile devices/ 25 user equipment (UE) to connect to a cellular network. It 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 30 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
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5 devices often support multiple RATs, allowing them to connect to different types of networks and provide optimal performance based on the available network resources.
In addition, 5G communication systems need to support services capable of 10 simultaneously reflecting and satisfying various requirements of users, service providers, etc. Services considered for the 5G communication systems include enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliability low-latency communication (URLLC) services.
15 As discussed in the background section, one of the significant issues in the prior art is the prolonged periods during which devices remain deregistered after receiving registration rejection messages from the 5G network. This occurs due to the lack of proper mechanisms to handle registration failures for 4G only SIMs in 5G networks. As a result of prolonged deregistration periods, users experience disrupted
20 connectivity, leading to a poor user experience. Devices are unable to quickly transition to a compatible network (such as 4G) after being rejected by the 5G network, resulting in a loss of network access and service disruptions. The prior art often lacks clarity in the reasons for registration rejection, making it difficult for devices to understand the cause of the failure and take appropriate corrective
25 actions. This lack of transparency further exacerbates the issue of prolonged deregistration. The inability of devices to quickly switch between networks following a registration rejection leads to inefficient utilization of network resources. This inefficiency can strain network capacity and impact overall network performance. In some cases, the prior art may not adequately address security
30 concerns during the registration process, particularly when authenticating the identity of devices attempting to connect to the network. This can pose risks to network integrity and user privacy.
14

5 The present disclosure aims to overcome the above-mentioned and other existing problems in this field of technology.
The present disclosure addresses the problems in the existing art by providing a method and system that enable efficient registration of 4G only SIMs in 5G
10 networks, thereby overcoming the issues of prolonged deregistration periods and ensuring continuous connectivity for users. The method begins by receiving a registration request from a user equipment (UE) attempting to establish a connection with a 5G network. This step is crucial as it initiates the registration process for UEs with 4G only SIMs in a 5G network environment. To ensure
15 security and authorization, the method involves authenticating the UE's identity based on communication with an authentication network node, such as the Authentication Server Function (AUSF). This step prevents unauthorized access and ensures that only legitimate UEs attempt to connect to the network. Upon encountering a failure in the authentication process, the method acknowledges the
20 issue of 4G only SIMs not being provisioned in the 5G network by receiving a registration reject message from the authentication network node.
One of the key aspects of the method is the mapping of the registration reject message with a plurality of error codes to identify a specific error cause code. This
25 step addresses the problem of unclear rejection reasons in the prior art by providing clarity on the cause of the registration failure. This clarity allows for more precise handling of registration rejections and enables the network to provide specific instructions to the affected UE. The transmission of the registration reject message to the UE, along with the identified error cause code, is a critical step in informing
30 the UE of the exact reason for the registration failure. As used herein, error cause code corresponds to a code (e.g., example, HTTP failure cause code 404, HTTP bad request code 400) used to indicate the specific reasons for the rejection of the registration request. This enables the UE to take appropriate actions, such as attempting to connect to a 4G network, thereby avoiding prolonged deregistration
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5 periods. The method specifically addresses the issue of 4G only SIMs attempting to connect to a 5G network by identifying an error cause code corresponding to the non-allowance of N1 mode by the 5G network. This direct response ensures that the UE can quickly switch to a compatible network, maintaining continuous connectivity.
10
It would be appreciated by the person skilled in the art that, the present disclosure provides a comprehensive solution to the problems identified in the prior art by ensuring that UEs with 4G only SIMs can efficiently register in compatible networks without experiencing prolonged periods of deregistration and
15 connectivity disruption. The present disclosure offers a secure, clear, and efficient process for handling registration failures and enables UEs to maintain continuous connectivity by swiftly transitioning to compatible networks.
Hereinafter, exemplary embodiments of the present disclosure will be described 20 with reference to the accompanying drawings.
FIG. 1 illustrates an exemplary block diagram representation of 5th generation core (5GC) network architecture [100], in accordance with exemplary embodiment of the present disclosure. As shown in FIG. 1, the 5GC network architecture [100]
25 includes a user equipment (UE) [102], a radio access network (RAN) or gNodeB [104], a plurality if network functions or network entities such as, an access and mobility management function (AMF) [106], a Session Management Function (SMF) unit [108], a Service Communication Proxy (SCP) [110], an Authentication Server Function (AUSF) [112], a Network Slice Specific Authentication and
30 Authorization Function (NSSAAF) [114], a Network Slice Selection Function (NSSF) [116], a Network Exposure Function (NEF) [118], a Network Repository Function (NRF) [120], a Policy Control Function (PCF) [122], a Unified Data Management (UDM) [124], an application function (AF) [126], a User Plane Function (UPF) [128], a data network (DN) [130], wherein all the components are
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5 assumed to be connected to each other in a manner as obvious to the person skilled in the art for implementing features of the present disclosure.
The User Equipment (UE) [102] interfaces with the network via the Radio Access Network (RAN) [104]; the Access and Mobility Management Function (AMF)
10 [106] manages connectivity and mobility, while the Session Management Function (SMF) unit [108] administers session control; the service communication proxy (SCP) [110] routes and manages communication between network services, enhancing efficiency and security, and the Authentication Server Function (AUSF) [112] handles user authentication; the Non-Standalone Access Architecture
15 Function (NSSAAF) [114] for integrating the 5G core network with existing 4G LTE networks i.e., to enable Non-Standalone (NSA) 5G deployments, the Network Slice Selection Function (NSSF) [116], Network Exposure Function (NEF) [118], and Network Repository Function (NRF) [120] enable network customization, secure interfacing with external applications, and maintain network function
20 registries respectively; the Policy Control Function (PCF) [122] develops operational policies, and the Unified Data Management (UDM) [124] manages subscriber data; the Application Function (AF) [126] enables application interaction, the User Plane Function (UPF) [128] processes and forwards user data, and the Data Network (DN) [130] connects to external internet resources;
25 collectively, these components are designed to enhance mobile broadband, ensure low-latency communication, and support massive machine-type communication, solidifying the 5GC as the infrastructure for next-generation mobile networks.
Radio Access Network (RAN) [104] is the part of a mobile telecommunications
30 system that connects user equipment (UE) [102] to the core network (CN) and
provides access to different types of networks (e.g., 5G network). It consists of radio
base stations and the radio access technologies that enable wireless communication.
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5 Access and Mobility Management Function (AMF) [106] (alternatively referred to as AMF unit [106]) is a 5G core network function responsible for managing access and mobility aspects, such as UE registration, connection, and reachability. It also handles mobility management procedures like handovers and paging.
10 Session Management Function (SMF) [108] is a 5G core network function responsible for managing session-related aspects, such as establishing, modifying, and releasing sessions. It coordinates with the User Plane Function (UPF) for data forwarding and handles IP address allocation and QoS enforcement.
15 Service Communication Proxy (SCP) [110] is a network function in the 5G core network that facilitates communication between other network functions by providing a secure and efficient messaging service. It acts as a mediator for service-based interfaces.
20 Authentication Server Function (AUSF) [112] is a network function in the 5G core responsible for authenticating UEs during registration and providing security services. It generates and verifies authentication vectors and tokens.
Network Slice Specific Authentication and Authorization Function (NSSAAF) 25 [114] is a network function that provides authentication and authorization services specific to network slices. It ensures that UEs can access only the slices for which they are authorized.
Network Slice Selection Function (NSSF) [116] is a network function responsible 30 for selecting the appropriate network slice for a UE based on factors such as subscription, requested services, and network policies.
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5 Network Exposure Function (NEF) [118] is a network function that exposes capabilities and services of the 5G network to external applications, enabling integration with third-party services and applications.
Network Repository Function (NRF) [120] is a network function that acts as a 10 central repository for information about available network functions and services. It facilitates the discovery and dynamic registration of network functions.
Policy Control Function (PCF) [122] is a network function responsible for policy control decisions, such as QoS, charging, and access control, based on subscriber 15 information and network policies.
Unified Data Management (UDM) [124] is a network function that centralizes the management of subscriber data, including authentication, authorization, and subscription information. 20
Application Function (AF) [126] is a network function that represents external applications interfacing with the 5G core network to access network capabilities and services.
25 User Plane Function (UPF) [128] is a network function responsible for handling user data traffic, including packet routing, forwarding, and QoS enforcement.
Data Network (DN) [130] refers to a network that provides data services to user equipment (UE) in a telecommunications system. The data services may include 30 but are not limited to Internet services, private data network related services.
In an exemplary embodiment, the UE [102] is enabled with a Subscriber Identity Module (SIM) configured to operate only on a 4G network. The UE [102] attempts to register or latch to a 5G core network either through initiation NAS registration
19

5 process or through 4G to 5G idle mode mobility registration process. A registration request is generated based on the attempt of the UE [102] to connect to the 5GC. The generated registration request may be transmitted to the AMF [106]. Upon receiving the registration request from the UE [102], the AMF [106] communicates the registration request to the AUSF [112] or UDM [124] in order to authenticate
10 and register the UE [102] to the 5G services. However, the AUSF [112] or UDM [124] rejects the registration request from the AMF [106] since the SIM is configured to operate only on the 4G network.
A registration reject message (alternatively referred to as message) transmitted from 15 the AUSF [112] or the UDM [124] to the AMF [106] may include e.g., HTTP error cause code (i.e., HTTP failure cause code 404, HTTP bad request code 400, HTTP unauthorized code 401, HTTP forbidden code 403, HTTP not found code 404, etc.) since the registration request is received from the SIM that is configured to operate only on the 4G network. Thus, the UE [102] cannot be registered or cannot be 20 latched to the 5G core network. In response to receiving the registration reject message from the AUSF [112] or UDM [124], the AMF [106] is configured to map the registration reject message with a first information.
The AMF [106] may map the registration reject message e.g., HTTP error cause 25 code with the first information e.g., the NAS cause code (i.e., N1 mode not allowed). The first information e.g., the NAS cause code (i.e., N1 mode not allowed) is based on HTTP error cause code (“User not found”) received from the AUSF [112] or UDM [124].
30 As used herein, the HTTP error code corresponds to an error (such as 404 NOT Found) received during communication between client devices (such as UEs) and network, indicating the failure or unavailability of the requested resource on the network.
20

5 As used herein, the NAS cause code corresponds to an error (such as 'N1 mode not allowed') received during communication between user equipment (UE) and the mobile network's Non-Access Stratum (NAS), indicating the failure or unavailability of certain network functions or procedures required for the establishment or maintenance of a mobile connection. Further, NAS cause codes
10 facilitate in diagnosing and troubleshooting issues within the mobile network, providing valuable insights into the reasons behind connection failures or disruptions experienced by the UE.
Overall, the NAS cause code provides the reason for the rejections and 15 communicates the same to the UE [102]. Every cause code denotes a distinct reason for the rejection and the same depends on the kind of HTTP error cause codes. Still further, the AMF is configured to contact AUSF/UDM for authentication.
Thereafter, the UE [102] is configured to receive the registration reject message 20 mapped with the first information e.g., the NAS cause code, from the AMF [106]. The registration reject message mapped with the first information e.g., the NAS cause code (i.e., N1 mode not allowed) indicates the UE to disable N1 mode and immediately attempt to register or establish connection with the 4G network. Thus, the UE can establish a connection with the 4G network as soon as the registration 25 reject message mapped with the NAS cause code is received by the UE, thereby allowing the UE to establish a connection with the 4G network without configuring a timer and without being in a deregistered state for a long time.
FIG. 2 illustrates an exemplary block diagram of a system [200] comprising a 30 network node (such as AMF) in communication with a UE, in accordance with exemplary embodiments of the present disclosure. As shown in FIG. 2, the system [200] includes a receiving unit [202], an authentication unit [204], a mapping unit [206], and a transmitting unit [208].
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5 The network node includes the receiving unit [202]. The receiving unit [202] within the network node (such as AMF [106]) facilitates establishing a connection between the User Equipment (UE) [102] and a first network, such as a 5th Generation (5G) network. The receiving unit [202] is specifically configured to handle incoming communication from the UE [102], which is seeking to access the network's
10 services. The primary function of the receiving unit [202] is to receive a registration request from the UE [102]. The registration request is a communication sent by the UE [102] to the network, indicating its desire to establish a connection with the first network. The registration request typically contains essential information about the UE [102], such as its identity and the type of services it wishes to access. Upon
15 receiving the registration request, the receiving unit [202] processes the incoming communication and transmits the relevant information to other components within the network node (such as AMF [106]), such as the authentication unit [204]. The successful reception of the registration request by the receiving unit [202] initiates the subsequent steps in the registration process, including the authentication of the
20 UE's [102] identity and the eventual establishment of a connection between the UE [102] and the first network.
The network node includes the authentication unit [204]. The authentication unit [204] facilitates in ensuring the security and integrity of the network by verifying
25 the identity of the User Equipment (UE) [102] attempting to establish a connection. The process begins when the UE [102] sends a registration request to the network, indicating a request to connect to the first network (such as 5G network). Upon receiving this registration request, the authentication unit initiates communication with an authentication network node, such as an Authentication Server Function
30 (AUSF) [112]. The primary function of this communication is to authenticate the identity of the UE [102], ensuring that only authorized devices (such as UE [102]) can access the network's services. The authentication process involves various security protocols and checks, which may include verifying digital certificates, checking credentials such as usernames and passwords, or other forms of identity
22

5 verification. Once the authentication is successful, the UE [102] is granted access to the network, allowing it to establish a connection and utilize the network's services. However, if the authentication fails, the network node (such as AMF [106]) will not allow the connection to be established, and the UE [102] will be notified of the failure, typically through a registration reject message.
10
The registration reject message is then sent to the network node (such as AMF [106]), where it is received by the receiving unit [202]. The receiving unit [202] is responsible for processing this message and taking appropriate actions based on its contents. Typically, the registration reject message will include information about
15 the reason for the rejection, such as an error code or a description of the authentication failure. This information is crucial for diagnosing the issue and for the UE [102] to take corrective actions, such as reattempting registration with the correct credentials or seeking technical support.
20 The network node includes the mapping unit [206]. The mapping unit [206] facilitates in handling registration reject messages received from the authentication network node. When the authentication of a User Equipment's (UE) identity fails, a registration reject message is generated and sent to the network node. The message may comprise error codes that indicate the specific reasons for the rejection of the
25 registration request. The role of the mapping unit is to interpret these error codes and map them to a corresponding error cause code. This involves analyzing the error codes provided in the registration reject message and matching them to predefined error cause codes that are understood by both the network and the UE. These error cause codes provide a more detailed and standardized explanation of
30 why the registration request was rejected. For example, an error code in the registration reject message might indicate a failure in authentication due to incorrect credentials. The mapping unit would then map this error code to a specific error cause code that corresponds to "authentication failure." This mapped error cause code is then used in subsequent communications with the UE to inform it of the
23

5 specific reason for the registration rejection. By mapping the error codes to corresponding error cause codes, the mapping unit facilitates clearer communication between the network and the UE. It helps in diagnosing the issue that led to the registration rejection and enables the UE to take appropriate corrective actions, such as reattempting registration with the correct credentials or
10 addressing any other identified issues.
The network node includes the transmitting unit [208]. The transmitting unit [208] transmits the registration reject message to the UE [102], along with the identified error cause code. When the UE [102] attempts to register with the network and the
15 authentication process fails, a registration reject message is generated by the authentication network node (such as AUSF [112]) and received by the receiving unit [202] of the network node (such as AMF [106]). The message is then processed by the mapping unit, which maps the message with a plurality of error codes to identify the specific error cause code that corresponds to the reason for the rejection.
20 Once the error cause code is identified, it is the responsibility of the transmitting unit [208] to send this information back to the UE. The transmitting unit takes the registration reject message and the identified error cause code and packages them into a response that is sent to the UE. This response informs the UE that its registration request has been rejected and provides the specific reason for the
25 rejection, as indicated by the error cause code. The transmission of the registration reject message along with the error cause code is crucial for several reasons. Firstly, it provides transparency to the UE [102] about the registration process, allowing it to understand why its request was denied. Secondly, it enables the UE to take corrective actions based on the specific error cause, such as updating its credentials
30 or addressing any configuration issues. Lastly, it ensures efficient communication between the network node and the UE, facilitating a more secure and reliable registration process.
24

5 FIG. 3 illustrates an exemplary sequence diagram indicating the process of mapping HTTP error cause code to NAS cause code, in accordance with exemplary embodiments of the present disclosure. As shown in FIG. 3, the sequence diagram [300] includes the UE [102], a Mobility Management Entity (MME) [302], the AMF [106], and the AUSF [112]. The sequence of steps is performed by the UE
10 [102], the MME [302], the AMF [106], and the AUSF [112] for mapping HTTP error cause code to NAS cause code.
At step S1, the UE [102] sends a registration request to the AMF [106] to establish a connection with the 5G network. This is the initial step where the UE [102] 15 indicates its intention to connect to the network (such as 5G network).
At step S2, upon receiving the registration request, the AMF [106] forwards the necessary information to the AUSF [112] to authenticate the identity of the UE [102] for ensuring that only authorized UEs can access the network. 20
At step S3, If the AUSF [112] fail to authenticate the UE [102], for reasons such as incorrect credentials, identity or security issues, it sends a message back to the AMF [106] indicating the failure.
25 At step S4, the AMF [106] receives the authentication failure message from the AUSF [112]. This informs the AMF that the UE could not be authenticated and, therefore, cannot be allowed to connect to the network. Next, the AMF [106] internally checks the failure message and maps the error using HTTP2 to NAS (Non-Access Stratum) cause code mapping. The AMF [106] decides which 5GMM
30 (5G Mobility Management) cause to include in the Registration Reject message that will be sent back to the UE.
As used herein, “5GMM" stands for 5G Mobility Management, a specific subset of the NAS protocol responsible for managing mobility-related procedures in 5G
25

5 networks. The mobility-related procedures may include but are not limited to registration, authentication, paging, handovers, and mobility state management for UE.
A "5GMM cause code" indicates the reason for a particular issue, event or condition 10 occurring within the 5G Mobility Management procedures. The network may send a 5GMM cause code to the UE to convey the reason associated with failure IN mobility related procedures.
At step S5, the AMF [106] sends the Registration Reject message to the UE [102]. 15 This message includes the 5GMM cause code that was decided in the previous step, informing the UE [102] why the registration was rejected.
At step S6, upon receiving the Registration Reject message with the cause code (i.e., N1 mode not allowed), the UE [102] understands that N1 mode is not allowed 20 and thus disable its N1 capabilities, which are related to 5G access, and instead try to latch or attach to the network using 4G capabilities at the MME [302].
At step S7 and S8, the UE [102] initiating the procedure to attach to the 4G network, following the rejection from the 5G network due to failed authentication. The UE 25 attempt to register with the 4G network to gain network access for various network services.
FIG. 4 illustrates another exemplary method flow diagram indicating the process for network registration in a wireless communication system, in accordance with 30 exemplary embodiments of the present disclosure. As shown in FIG. 4, the method [400] starts at step [402].
At step 404, the method [400] as disclosed by the present disclosure comprises receiving, at a network node (such as AMF [106]) from a UE [102], a registration
26

5 request for establishment of a connection between the UE [102] and a first network (such as 5G network). The first network is a 5th Generation (5G) network.
The registration request corresponds to a communication from the UE [102]. The registration request may include necessary identification and access information
10 which the first network (such as 5G network) requires to initiate the UE's authentication process. The information typically includes the UE's identity, subscription details, and the type of services it wishes to access. The network node (such as AMF [106]) then processes this registration request to determine whether the UE [102] is authorized to connect to and use the network services.
15
Next, at step 406, the method [400] as disclosed by the present disclosure comprises authenticating, by the network node such as AMF [106], an identity of the UE [102] based on a communication with an authentication network node for the received registration request. The authentication network node corresponds to one of an
20 AUSF [112] and UDM [124] associated with the first network.
The authentication process is executed following the reception of the registration request from the UE [102]. The authentication is performed by the authentication network node (such as the AUSF [112] or UDM [124]) depending on the network's
25 architecture and the specifics of the implementation. The communication between the AMF [106] and the authentication network node (such as the AUSF [112] or UDM [124]) involves exchanging information and credentials provided by the UE [102] as part of the registration request. The authentication network node (such as the AUSF [112] or UDM [124]) examines these credentials, which could include a
30 range of data points from basic identification numbers to more complex cryptographic tokens or certificates. Either the UE's identity is successfully authenticated, allowing the registration process to proceed to the next step, or it fails. In the event of failure, subsequent steps would involve notifying the UE [102] of the unsuccessful attempt, typically involving the issuing of a registration reject
27

5 message with appropriate cause codes to inform the UE of the reason behind the authentication failure. This ensures that only UEs with verified identities can establish a connection with the first network (such as 5G network), thereby maintaining the integrity and security of the network.
10 Next, at step 408, the method [400] as disclosed by the present disclosure comprises receiving, at the network node (such as AMF [106]), a registration reject message from the authentication network node (such as AUSF [112] or UDM [124]) based on a failure of the authentication of the identity of the UE [102].
15 The reception of the registration reject message by the AMF [106] is based on failure to authenticate the identity of the User Equipment (UE) [102]. The authentication failure can result from various issues, such as discrepancies in the credentials provided by the UE, the absence of requisite authorization, or other security-related concerns that prevent the authentication network node from
20 verifying the UE's identity. The registration reject message serves as a notification to the AMF [106] that the authentication process has not been successful, and as a result, the UE [102] cannot be granted access to the first network (such as 5G network). The reception of the registration reject message triggers the network node (such as AMF [106]) to take further action, which typically involves informing the
25 UE [102] about the unsuccessful registration attempt, often including specific cause codes that explain the reason for the rejection. This information allows the UE [106] to recognize the nature of the problem and to take corrective measures if possible. In an exemplary embodiment, the UE [102] is a 4G only SIM and is not provisioned in 5G network.
30
Next, at step 410, the method [400] as disclosed by the present disclosure comprises mapping, by the network node such as AMF [106], the registration reject message with a plurality of error codes to identify an error cause code. The plurality of error
28

5 codes corresponds to Non-Access Stratum (NAS) cause codes associated with the registration reject message.
The AMF [106] node maps the received registration reject message (For example, HTTP failure cause code 404, HTTP bad request code 400, HTTP unauthorized
10 code 401, HTTP forbidden code 403, HTTP not found code 404, etc.) from the AUSF [112] or UDM [124] with a plurality of NAS cause error codes to identify an error cause code. The error cause code may be “Illegal UE” or "USER_NOT_FOUND", as per 3GPP specification, however, this way of mapping and further processing is greater time consuming. To overcome this issue, the AMF
15 [106] nodes, as per the present disclosure, maps this HTTP error cause code with "N1 mode not allowed" in the NAS cause code.
Next, at step 412, the method [400] as disclosed by the present disclosure comprises transmitting, by the network node such as AMF [106], the registration reject 20 message to the UE [102] along with the identified error cause code.
Following the mapping process where the AMF [106] has identified the specific error cause code associated with the authentication failure, the network node is then tasked with transmitting this information back to the UE [102]. This transmission
25 includes both the registration reject message—which is a notification that the UE’s request for network access has been denied and the identified error cause code which provides clarity on the specific reason for the registration failure. The error cause code is essential as it helps the user or the technical team supporting the UE to understand the nature of the problem that led to the authentication failure. With
30 this information, appropriate remedial actions can be planned and executed. For instance, if the error cause code indicates an issue with the UE's credentials, the user may need to enter the correct credentials or reset them if necessary.
29

5 For example, the AMF [106] sends the registration reject message along with the identified error cause code "N1 mode not allowed" to the UE [102]. On receiving the reject message with this NAS cause code, the UE [102] device disables the N1 mode and immediately attempts to establish a connection with a second network, wherein the second network is a 4th Generation (4G) network.
10
In an implementation of the present disclosure, a subsequent registration request for the establishment of a connection with the first network (such as a 5G network) may be transmitted by the UE upon the expiry of a predetermined time period. The predetermined time period may correspond to a defined interval during which the
15 UE may not send any further registration requests to establish a connection with the first network. This allows the UE to remain latched with the second network (such as a 4G network) for a longer duration in case of connection failure with the first network. Further, the proposed solution also permits the UE to retry latching to the 5G network after the predetermined time period (e.g., 12 hours), thereby preventing
20 permanent rejection of the registration request and offering the UE options for connecting to the 5G network. This reduces the number of attempts made by the UE to attach to the 5G network, enhances efficiency, and ensures seamless and uninterrupted services for the UE user.
25 Thereafter, the method [400] terminates at step [414].
In an example, a smartphone (UE) is attempting to connect to a 5th Generation (5G) mobile network. The smartphone sends a registration request to the network's Access and Mobility Management Function (AMF) to establish a connection. The 30 AMF forwards this request to the Authentication Server Function (AUSF) to authenticate the smartphone's identity. If the authentication fails, the AUSF sends a registration reject message back to the AMF, indicating the failure. The AMF then maps this reject message with a set of error codes to identify the specific reason for the failure, which could be due to non-allowance of N1 mode by the 5G network.
30

5 Finally, the AMF sends the registration reject message along with the identified error cause code back to the smartphone. This informs the smartphone that it cannot connect to the 5G network and should instead attempt to establish a connection with a 4th Generation (4G) network, for which it might be configured with a Subscriber Identity Module (SIM).
10
In an exemplary aspect of the present disclosure, the present description is not restricted to only 5G or 4G networks. The present disclosure may be implemented between two different or higher and lower Network(s) technology with the same scope of the implementation of the invention.
15
FIG. 5 illustrates an exemplary block diagram of a computer system [500] upon which an embodiment of the present disclosure may be implemented. In an implementation, the computing device implements the method for mapping HTTP error cause code to NAS cause code using the system [200]. In another
20 implementation, the computing device itself implements the method for mapping HTTP error cause code to NAS cause code by using one or more units configured within the computing device, wherein said one or more units are capable of implementing the features as disclosed in the present disclosure.
25 The computer system [500] may include a bus [502] or other communication mechanism for communicating information, and a processor [504] coupled with bus [502] for processing information. The processor [504] may be, for example, a general-purpose microprocessor. The computer system [500] may also include a main memory [506], such as a random-access memory (RAM), or other dynamic
30 storage device, coupled to the bus [502] for storing information and instructions to be executed by the processor [504]. The main memory [506] also may be used for storing temporary variables or other intermediate information during execution of the instructions to be executed by the processor [504]. Such instructions, when stored in non-transitory storage media accessible to the processor [504], render the
31

5 computer system [500] into a special-purpose machine that is customized to perform the operations specified in the instructions. The computer system [500] further includes a read only memory (ROM) [508] or other static storage device coupled to the bus [502] for storing static information and instructions for the processor [504].
10
A storage device [510], such as a magnetic disk, optical disk, or solid-state drive is provided and coupled to the bus [502] for storing information and instructions. The computer system [500] may be coupled via the bus [502] to a display [512], such as a cathode ray tube (CRT), for displaying information to a computer user. An
15 input device [514], including alphanumeric and other keys, may be coupled to the bus [502] for communicating information and command selections to the processor [504]. Another type of user input device may be a cursor control [516], such as a mouse, a trackball, or cursor direction keys, for communicating direction information and command selections to the processor [504], and for controlling
20 cursor movement on the display [512]. The input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allow the device to specify positions in a plane.
The computer system [500] may implement the techniques described herein using 25 customized hard-wired logic, one or more ASICs or FPGAs, firmware and/or program logic which in combination with the computer system [500] causes or programs the computer system [500] to be a special-purpose machine. According to one embodiment, the techniques herein are performed by the computer system [500] in response to the processor [504] executing one or more sequences of one or 30 more instructions contained in the main memory [506]. Such instructions may be read into the main memory [506] from another storage medium, such as the storage device [510]. Execution of the sequences of instructions contained in the main memory [506] causes the processor [504] to perform the process steps described
32

5 herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions.
The computer system [500] also may include a communication interface [518] coupled to the bus [502]. The communication interface [518] provides a two-way
10 data communication coupling to a network link [520] that is connected to a local network [522]. For example, the communication interface [518] may be an integrated services digital network (ISDN) card, cable modem, satellite modem, or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, the communication interface [518] may be a
15 local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, the communication interface [518] sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.
20
The computer system [500] can send messages and receive data, including program code, through the network(s), the network link [520] and the communication interface [518]. In the Internet example, a server [530] might transmit a requested code for an application program through the Internet [528], the Internet Service
25 Provider (ISP) [526], the local network [522] and the communication interface [518]. The received code may be executed by the processor [504] as it is received, and/or stored in the storage device [510], or other non-volatile storage for later execution.
30 According to yet another aspect of the present disclosure, a non-transitory computer-readable storage medium storing instruction, the storage medium comprising executable code which, when executed by one or more units of a system, causes: a receiving unit [202] to receive, from a user equipment (UE) [102], a registration request for establishment of a connection between the UE [102] and

5 a first network; an authentication unit [204] to authenticate an identity of the UE [102] based on a communication with an authentication network node for the received registration request; the receiving unit [202] to receive a registration reject message from the authentication network node based on a failure of the authentication of the identity of the UE [102]; a mapping unit [206] to map the
10 registration reject message with a plurality of error codes to identify a corresponding error cause code; and a transmitting unit [208] to transmit the registration reject message to the UE [102] along with the identified error cause code.
15 While considerable emphasis has been placed herein on the disclosed embodiments, it will be appreciated that many embodiments can be made and that many changes can be made to the embodiments without departing from the principles of the present disclosure. These and other changes in the embodiments of the present disclosure will be apparent to those skilled in the art, whereby it is to be understood
20 that the foregoing descriptive matter to be implemented is illustrative and non-limiting.

5 We Claim:
1. A method implemented by a network node, the method comprising:
receiving, at the network node from a user equipment (UE) [102], a
registration request for establishment of a connection between the UE [102]
and a first network;
10 authenticating, by the network node, an identity of the UE [102] based
on a communication with an authentication network node for the received registration request;
receiving, at the network node, a registration reject message from the authentication network node based on a failure of the authentication of the 15 identity of the UE [102];
mapping, by the network node, the registration reject message with a plurality of error codes to identify an error cause code; and
transmitting, by the network node, the registration reject message to the UE [102] along with the identified error cause code. 20
2. The method as claimed in claim 1, wherein the network node is an Access and Mobility Management Function (AMF) associated with the first network, wherein the first network is a 5th Generation (5G) network.
3. The method as claimed in claim 1, wherein the authentication network node
corresponds to an Authentication Server Function (AUSF) [112] associated
25 with the first network.
4. The method as claimed in claim 1, wherein the registration reject message comprises at least one of a plurality of HTTP failure cause codes.
5. The method as claimed in claim 1, wherein the plurality of error codes corresponds to Non-Access Stratum (NAS) cause codes associated with the
30 registration reject message.
6. The method as claimed in claim 1, wherein the error cause code corresponds
to non-allowance of N1 mode by the first network.

5 7. The method as claimed in claim 1, wherein the registration request is received from the UE [102] enabled with a subscriber identity module (SIM) configured to operate on a second network.
8. The method as claimed in claim 7, wherein the transmission of the registration
reject message to the UE [102] along with the identified error cause code
10 indicates the UE [102] to disable N1 mode and attempt to establish a connection with the second network, wherein the second network is a 4th Generation (4G) network.
9. A network node comprising:
a receiving unit [202] configured to receive, from a user equipment 15 (UE) [102], a registration request for establishment of a connection between the UE [102] and a first network;
an authentication unit [204] configured to authenticate an identity of the
UE [102] based on a communication with an authentication network node for
the received registration request;
20 the receiving unit [202] configured to receive a registration reject
message from the authentication network node based on a failure of the authentication of the identity of the UE [102];
a mapping unit [206] configured to map the registration reject message with a plurality of error codes to identify a corresponding error cause code; 25 and
a transmitting unit [208] configured to transmit the registration reject message to the UE [102] along with the identified error cause code.
10. The network node as claimed in claim 9, wherein the network node is an
Access and Mobility Management Function (AMF) associated with the first
30 network, wherein the first network is a 5th Generation (5G) network.
11. The network node as claimed in claim 9, wherein the authentication network
node corresponds to an Authentication Server Function (AUSF) 112
associated with the first network.

5 12. The network node as claimed in claim 9, wherein the registration reject
message comprises at least one of a plurality of HTTP failure cause codes. 13. The network node as claimed in claim 9, wherein the plurality of error codes
corresponds to Non-Access Stratum (NAS) cause codes associated with the
registration reject message. 10
14. The network node as claimed in claim 9, wherein the error cause code
corresponds to non-allowance of N1 mode by the first network.
15. The network node as claimed in claim 9, wherein the registration request is
received from the UE [102] enabled with a subscriber identity module (SIM)
configured to operate on a second network. 15
16. The network node as claimed in claim 15, wherein the transmission of the
registration reject message to the UE [102] along with the identified error
cause code indicates the UE [102] to disable N1 mode and attempt to
establish a connection with the second network, wherein the second network
is a 4th Generation (4G) network.
20
Dated this 3rd day of July 2023
(GARIMA SAHNEY)
IN/PA-1826
(AGENT FOR THE APPLICANT(S)
25 OF SAIKRISHNA & ASSOCIATES