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 HANDOVER FROM WLAN TO NEW RADIO (NR) IN A WIRELESS 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.

METHOD AND SYSTEM FOR PERFORMING HANDOVER FROM WLAN TO NEW RADIO (NR) IN A WIRELESS NETWORK
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates generally to the field of wireless communication systems. More particularly, the present disclosure relates to methods and systems for performing handover from WLAN to New Radio (NR) in a wireless network.
BACKGROUND
[0002] 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.
[0003] Wireless communication technology has rapidly evolved over the past few decades, with each generation bringing significant improvements and advancements. The first generation of wireless communication technology was based on analog technology and offered only voice services. However, with the advent of the second-generation (2G) technology, digital communication and data services became possible, and text messaging was introduced. 3G technology marked the introduction of high-speed internet access, mobile video calling, and location-based services. The fourth-generation (4G) technology revolutionized wireless communication with faster data speeds, better network coverage, and improved security. Currently, the fifth-generation (5G) technology is being deployed, promising even faster data speeds, low latency, and the ability to connect

multiple devices simultaneously. With each generation, wireless communication technology has become more advanced, sophisticated, and capable of delivering more services to its users.
[0004] Existing telecommunications networks face several challenges when handling handovers, particularly when transitioning between different types of access networks. For example, when a User Equipment (UE) attempts to handover from a Wireless Local Area Network (WLAN) access evolved packet data gateway (ePDG) to a New Radio (NR) Access Network, it sends a Protocol Data Unit (PDU) Session Establishment request to the Access and Mobility Management Function (AMF). This request is meant to indicate that the UE wants to continue using an existing PDU session in the new network environment. However, problems arise when the AMF is unable to find the Session Management Function (SMF) that was responsible for managing the PDU session in the WLAN network. This failure to identify the correct SMF can occur for various reasons, such as network configuration changes, SMF unavailability, or mismatches in the PDU Identifier (PDU ID) provided by the UE. As a result of this failure, the handover process is typically aborted, and the UE receives a negative response from the AMF. This can lead to several issues: . Some devices may persistently reattempt the handover, causing unnecessary
network traffic and potential battery drain on the UE. . Other devices may temporarily refrain from attempting any initial PDU Session
Establishment after receiving a negative response for the WLAN to NR
handover. This can lead to a period during which all call attempts to or from the
UE fail, significantly impacting the user experience.
[0005] Thus, in order to improve the third generation partnership project (3GPP) radio access network capacity and performance as well the above limitation, there exists an imperative need in the art to efficiently handle handover of UEs from

WLAN to New Radio (NR) in a wireless communication network, which the present disclosure aims to address.
OBJECTS OF THE INVENTION
[0006] Some of the objects of the present disclosure, which at least one embodiment disclosed herein satisfies are listed herein below.
[0007] It is an object of the present disclosure to provide a system and a method for performing handover from WLAN to NR.
[0008] It is another object of the present disclosure to provide a system and a method for performing handover from WLAN to NR that reduces the likelihood of call failures due to unestablished internet protocol multimedia subsystem (IMS) PDU sessions.
[0009] It is another object of the present disclosure to provide a system and a method for performing handover from WLAN to NR that improves the efficiency of handover procedures by converting failed handover attempts into initial PDU session establishments.
[0010] It is another object of the present disclosure to provide a system and a method for performing handover from WLAN to NR that enhances the user experience by minimizing disruptions in connectivity during network transitions.
[0011] It is another object of the present disclosure to provide a system and a method for performing handover from WLAN to NR that optimizes network resource utilization by preventing unnecessary reattempts of failed handover procedures.

[0012] It is another object of the present disclosure to provide a system and a method for performing handover from WLAN to NR that ensures seamless connectivity for users by dynamically adapting to changes in network conditions and configurations.
SUMMARY
[0013] 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.
[0014] According to an aspect of the present disclosure, a method implemented by a network node is disclosed. The method includes receiving, from a user equipment (UE), a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier (PDU ID) of an existing PDU session on a first type of network. The method further includes identifying, by the network node, an existing network node corresponding to the PDU ID tagged in the PDU session establishment request. Thereafter, the method includes initiating, by the network node, a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID.
[0015] In an aspect, the network node is an Access and Mobility Management Function (AMF).
[0016] In an aspect, the existing network node is an existing Session Management Function (SMF) responsible for facilitating the existing PDU session on the first type of network.

[0017] In an aspect, failure of the identification of the existing network node corresponding to the PDU ID is based on a failure in mapping of the existing SMF for the received PDU ID.
[0018] In an aspect, the target network node is a new SMF to initiate the new PDU session establishment procedure of the UE with a second type of network.
[0019] In an aspect, the method further comprises performing, by the network node, a handover of the UE from the first type of network to a second type of network based on an identification of the existing network node corresponding to the tagged PDU ID.
[0020] In an aspect, the first type of network is a wireless local-area network (WLAN) and the second type of network is a New Radio (NR) Access Network.
[0021] Another aspect of the present disclosure provides a network node comprising a receiving unit configured to receive, from a user equipment (UE), a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier (PDU ID) of an existing PDU session on a first type of network. The network node further comprises an identifying unit configured to identify an existing network node corresponding to the PDU ID tagged in the PDU session establishment request. The network node further comprises an initiating unit configured to initiate a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID.
[0022] Yet another aspect of the present disclosure, a non-transitory computer-readable storage medium storing instruction for performing handover from WLAN to NR is disclosed. The instructions include executable code which, when executed by one or more units of a system, may cause a receiving unit to receive, from a user

equipment (UE), a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier (PDU ID) of an existing PDU session on a first type of network; an identifying unit to identify an existing network node corresponding to the PDU ID tagged in the PDU session establishment request; and an initiating unit to initiate a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID.
BRIEF DESCRIPTION OF DRAWINGS
[0023] 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 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.
[0024] FIG. 1 illustrates an exemplary block diagram representation of 5th generation core (5GC) network architecture, in accordance with exemplary embodiment of the present disclosure.
[0025] FIG. 2 illustrates an exemplary block diagram of a system for performing handover from WLAN to New Radio (NR) in a wireless network, in accordance with exemplary embodiments of the present disclosure.

[0026] FIGs. 3A and 3B illustrates an exemplary signal flow diagram illustrating methods and systems for performing handover from WLAN to New Radio (NR) in a wireless network, in accordance with exemplary embodiments of the present disclosure.
[0027] FIG. 4 illustrates an exemplary method flow diagram illustrating methods and systems for performing handover from WLAN to New Radio (NR) in a wireless network, in accordance with exemplary embodiments of the present disclosure.
[0028] FIG. 5 illustrates an exemplary block diagram of a computing device upon which an embodiment of the present disclosure may be implemented.
[0029] FIG. 6 illustrates an exemplary sequence diagram for performing handover from WLAN to New Radio (NR) in a wireless network, in accordance with exemplary embodiments of the present disclosure.
[0030] The foregoing shall be more apparent from the following more detailed description of the disclosure.
DETAILED DESCRIPTION
[0031] 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

5 which like reference numerals refer to the same parts throughout the different drawings.
[0032] The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather,
10 the 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.
15
[0033] 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
20 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 other equivalent terms or variations thereof may be used interchangeably without departing from the scope of the invention as defined herein.
25
[0034] 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
30 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.
9

5 [0035] 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.
10 A process is terminated when its operations are completed but could have additional steps not included in a figure.
[0036] The word “exemplary” and/or “demonstrative” is used herein to mean serving as an example, instance, or illustration. For the avoidance of doubt, the
15 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
20 “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 elements.
25 [0037] 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 capable of receiving and/or transmitting one or parameters, performing function/s, communicating with other user devices and transmitting data to the
30 other user 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, Bluetooth, Bluetooth Low Energy, Near Field Communication, Z-Wave, Wi-Fi, Wi-Fi direct, etc. For
10

5 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 person skilled in the art for implementation of the features of the present disclosure.
10
[0038] 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 special purpose processor, a conventional processor, a digital signal processor, a
15 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, and/or any other functionality that enables the working of the system according to
20 the present disclosure. More specifically, the processor is a hardware processor.
[0039] As portable electronic devices and wireless technologies continue to improve and grow in popularity, the advancing wireless technologies for data transfer are also expected to evolve and replace the older generations of
25 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 generation (4G), and now fifth generation (5G), and more such generations are expected to continue in the forthcoming time.
30
[0040] Radio Access Technology (RAT) refers to the technology used by mobile devices/ 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
11

5 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),
10 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.
15
[0041] As used herein, the Access and Mobility Management Function (AMF) is a part of the 3GPP 5G Architecture. The primary tasks of AMF include but not limited to Registration Management, Connection Management, Reachability Management, Mobility Management and various function relating to security and
20 access management and authorization.
[0042] As used herein, the Session Management Function (SMF) is a part of control plane function within 5G Core Network. The main function of SMF includes but are not limited to PDU Session Management; IP Address Allocation; 25 general packet radio service tunnelling protocol-user plane (GTP-U) Tunnel Management; and Downlink Notification Management.
[0043] As used herein, the PDU Session Management includes setup, modification and release of PDU sessions. 30
[0044] As discussed in the background section, the Existing telecommunications networks face several challenges when handling handovers, particularly when transitioning between different types of access networks. For example, when a User Equipment (UE) attempts to handover from a Wireless Local Area Network
12

5 (WLAN) access (ePDG) to a New Radio (NR) Access Network, it sends a Protocol Data Unit (PDU) Session Establishment request to the Access and Mobility Management Function (AMF). This request is meant to indicate that the UE wants to continue using an existing PDU session in the new network environment.
10 [0045] However, problems arise when the AMF is unable to find the Session Management Function (SMF) that was responsible for managing the PDU session in the WLAN network. This failure to identify the correct SMF can occur for various reasons, such as network configuration changes, SMF unavailability, or mismatches in the PDU Identifier (PDU ID) provided by the UE. As a result of this 15 failure, the handover process is typically aborted, and the UE receives a negative response from the AMF. This can lead to several issues: . Some devices may persistently reattempt the handover, causing unnecessary
network traffic and potential battery drain on the UE.
. Other devices may temporarily refrain from attempting any initial PDU Session
20 Establishment after receiving a negative response for the WLAN to NR
handover. This can lead to a period during which all call attempts to or from the UE fail, significantly impacting the user experience.
[0046] To overcome these and other inherent problems in the art, the present 25 disclosure proposes a solution of implementing a method wherein the network node, upon receiving a PDU session establishment request from the UE, identifies an existing network node corresponding to the PDU ID tagged in the request. If the identification fails, the network node initiates a new PDU session establishment procedure via a target network node instead of aborting the handover process. To 30 further address the issue of failed handovers, the present disclosure introduces a method wherein the network node, identified as an Access and Mobility Management Function (AMF), performs a handover of the UE from the first type of network (e.g., WLAN) to a second type of network (e.g., NR Access Network) based on the identification of the existing network node corresponding to the tagged
13

5 PDU ID. This ensures a smoother transition between different types of networks. Additionally, the present disclosure aims to mitigate the problem of call failures during handover attempts by proposing a network node comprising a receiving unit, an identifying unit, and an initiating unit. These units work together to receive the PDU session establishment request, identify the corresponding existing network
10 node, and initiate a new PDU session establishment procedure if necessary. This approach reduces the chances of IMS PDU for the UE not being in an established state, thereby enhancing the user experience. Furthermore, the present disclosure provides a solution to the challenge of reattempts and delays in initial PDU Establishment by converting a failed handover attempt into an initial PDU
15 Establishment.
[0047] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.
20 [0048] 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] includes a user equipment (UE) [102], a radio access network (RAN) or gNodeB [104], a plurality if network functions or network entities such
25 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 Authorization Function (NSSAAF) [114], a Network Slice Selection Function (NSSF) [116], a Network Exposure Function (NEF) [118], a
30 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 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.
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5 [0049] The User Equipment (UE) [102] interfaces with the network via the Radio Access Network (RAN) [104]; the Access and Mobility Management Function (AMF) [106] manages connectivity and mobility, while the Session Management Function (SMF) unit [108] administers session control; the service communication
10 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 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
15 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 registries respectively; the Policy Control Function (PCF) [122] develops operational policies, and the Unified Data Management (UDM) [124] manages
20 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; collectively, these components are designed to enhance mobile broadband, ensure low-latency communication, and support massive machine-type communication,
25 solidifying the 5GC as the infrastructure for next-generation mobile networks.
[0050] Radio Access Network (RAN) [104] is the part of a mobile telecommunications system that connects user equipment (UE) [102] to the core network (CN) and provides access to different types of networks (e.g., 5G network). 30 It consists of radio base stations and the radio access technologies that enable wireless communication.
[0051] Access and Mobility Management Function (AMF) [106] (alternatively referred to as AMF unit [106]) is a 5G core network function responsible for
15

5 managing access and mobility aspects for both 3GPP and non-3GPP network accesses, including WLAN. It handles procedures such as UE registration, connection establishment, and reachability. Moreover, the AMF supports registration management, access control, and mobility management functions for both 3GPP and non-3GPP access to handle mobility management procedures like
10 handovers and paging.
[0052] 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 15 forwarding and handles IP address allocation and QoS enforcement.
[0053] 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 20 service-based interfaces.
[0054] 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.
25
[0055] Network Slice Specific Authentication and Authorization Function (NSSAAF) [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.
30
[0056] Network Slice Selection Function (NSSF) [116] is a network function responsible for selecting the appropriate network slice for a UE based on factors such as subscription, requested services, and network policies.
16

5 [0057] 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.
[0058] Network Repository Function (NRF) [120] is a network function that acts
10 as a central repository for information about available network functions and
services. It facilitates the discovery and dynamic registration of network functions.
[0059] Policy Control Function (PCF) [122] is a network function responsible for policy control decisions, such as QoS, charging, and access control, based on 15 subscriber information and network policies.
[0060] Unified Data Management (UDM) [124] is a network function that centralizes the management of subscriber data, including authentication, authorization, and subscription information. 20
[0061] 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 [0062] User Plane Function (UPF) [128] is a network function responsible for handling user data traffic, including packet routing, forwarding, and QoS enforcement.
[0063] Data Network (DN) [130] refers to a network that provides data services 30 to user equipment (UE) [102] in a telecommunications system. The data services may include but are not limited to Internet services, private data network related services.
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5 [0064] FIG. 2 illustrates an exemplary block diagram of a system [200] for performing handover from WLAN to New Radio (NR) in a wireless network, in accordance with exemplary embodiments of the present disclosure. As shown in FIG. 2, the system [200] includes a receiving unit [202], an identifying unit [204], an initiating unit [206], and a processing unit [208], wherein all the components are
10 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. Also, in FIG. 2 only a few units are shown, however, the system [200] may comprise multiple such units or the system [200] may comprise any such numbers of said units, as required to implement the features of the present disclosure. In an embodiment, the system
15 [200] may be incorporated in the network node (such as AMF [106]).
[0065] The system [200] comprises the receiving unit [202] configured to receive, from a user equipment (UE) [102], a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a
20 PDU Identifier (PDU ID) of an existing PDU session on a first type of network. The receiving unit [202] is designed to handle requests that specifically indicate the continuation of an existing PDU session by including the PDU ID associated with that session. In scenarios such as handovers, where the UE [102] moves from a first type of network, like a Wireless Local Area Network (WLAN), to a second type of
25 network, such as a New Radio (NR) Access Network the inclusion of the PDU ID in the request helps the network node to identify the specific PDU session that the UE [102] intends to maintain across different network types. Furthermore, the receiving unit [202] facilitates in ensuring seamless connectivity for the UE [102] during network handover. By accurately receiving and processing the PDU session
30 establishment request, the receiving unit [202] enables the network node to take appropriate actions to continue the existing PDU session or initiate a new session, if necessary, thereby enhancing the overall user experience.
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5 [0066] The system [200] comprises the identifying unit [204] communicatively coupled to the receiving unit [202]. The identifying unit [204] is configured to identify an existing network node corresponding to the PDU ID tagged in the PDU session establishment request received from the user equipment (UE) [102]. The identifying unit [204] compares the PDU ID provided in the request with a database
10 or registry of existing PDU sessions managed by various network nodes. When a match is found, the identifying unit [204] determines the specific network node associated with that PDU session to ensure that the correct network node is identified for the continuation or modification of the PDU session, thereby facilitating seamless connectivity for the UE [102] as it transitions between
15 different types of networks. If the existing network node (such as existing SMF [108]) is successfully identified, the network node (such as AMF [106]) can proceed with the appropriate actions to maintain or modify the PDU session as requested by the UE [102]. However, if the identification fails, the network node (such as AMF [106]) can take alternative measures, such as initiating a new PDU session
20 establishment procedure via a target network node, to ensure continuity of service for the UE [102]. This flexibility in response enhances the network's ability to adapt to various scenarios and maintain a high level of service quality.
[0067] The system [200] comprises the initiating unit [206] communicatively 25 coupled to the identifying unit [204]. The initiating unit [206] is configured to initiate a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID. The network node, AMF [106] node initiates a new PDU establishment procedure via a target network node, such as new SMF node [108A] based on a 30 failure of the identification of the existing network node, SMF node [108] corresponding to the PDU ID. In an exemplary aspect, the AMF node [106] initiates a new PDU session establishment procedure towards new SMF node [108A] in an event that existing SMF [108] for the tagged PDU ID given in PDU Establishment request from UE [102] is not found. In another exemplary aspect, the AMF node
19

5 [106] continues performing the handover procedure with the obtained SMF [108] in an event that SMF [108] for the tagged PDU ID given in PDU Establishment request from UE [102] is found.
[0068] The initiating unit [206] operates by triggering the establishment of a new 10 PDU session with the target network node, when the identifying unit [204] fails to match the PDU ID with an existing network node to ensure that the UE [102] can still establish a PDU session and maintain connectivity, even if the existing network node [such as SMF [108] is unavailable or cannot be identified for some reason. Furthermore, the initiating unit [206] facilitates in maintaining the quality of service 15 for the UE [102] during network transitions, such as handovers from a WLAN to an NR Access Network. By initiating a new PDU session establishment procedure, the initiating unit [206] helps to prevent service interruptions and call failures that might occur due to the inability to identify the existing network node.
20 [0069] The system [200] comprises the processing unit [208] configured to perform a handover of the UE [102] from the first type of network to a second type of network based on an identification of the existing network node corresponding to the tagged PDU ID. When the identification is successful, the handover procedure continues with the already identified session management function
25 (SMF). However, if there is a discrepancy in mapping and the existing SMF cannot be pinpointed, the processing unit is structured to bypass this issue by facilitating the creation of a new PDU session with a new SMF that is suited for the second type of network.
30 [0070] Referring to FIG. 3A an exemplary method flow diagram [300] for performing handover from WLAN to New Radio (NR) in a wireless network is shown, in accordance with exemplary embodiments of the present invention is shown. In an implementation the method [300] is performed by the system [200]. As shown in FIG. 3A, the method [300] starts at step [302].
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5 [0071] Next, at step [304], the method [300] comprises receiving, at an AMF [106], a PDU Establishment request from the UE [102] with the existing PDU type to transition the IMS PDU to NR. The AMF [106] begins to manage the handover of the PDU session, acknowledging the request from the UE [102] that indicates its
10 desire to continue an established PDU session in a new network environment, specifically transitioning from a WLAN to an NR Access Network.
[0072] Next, at step [306], the method [300] comprises checking, by the AMF [106], the SMF [108] where the IMS PDU Session was established through WLAN 15 access. The AMF [106] conducts a search or a query at the network repository function (NRF) to locate the existing SMF [108] that correlates with the PDU ID provided by the UE [102].
[0073] Next, at step [308], the method [300] comprises initiating, by the AMF 20 [106], a new PDU session establishment procedure towards an SMF [108] in the event the SMF [108] for the PDU ID given in the PDU Establishment request from the UE [102] is not found. Instead of terminating the session or leaving the UE [102] without service, the AMF [106] proactively initiates a new PDU session with an alternative SMF [108]. 25
[0074] Next, at step [310], the method [300] further includes the step of continuing to perform, by the AMF, the handover procedure with the obtained SMF in the event the SMF [108] for the PDU ID given in the PDU Establishment request from the UE is found. If the existing SMF [108] is successfully identified, the AMF 30 [106] continues with the handover process, ensuring a smooth transition for the UE [102] to the new NR Access Network.
[0075] The method terminates at step [312] after the handover procedure is completed.
21

5 [0076] Referring to FIG. 3B, an exemplary flow diagram illustrating method [300] for performing handover from WLAN to New Radio (NR) in a wireless network is shown, in accordance with exemplary embodiments of the present disclosure.
10
[0077] In the preferred and non-limiting embodiment of the present disclosure.
[0078] At step 320, the IMS PDUs are established through WLAN access (ePDG). The PDU is associated with a PDU ID
15
[0079] At step 322, the User Equipment (UE) [102] initiates the process by attempting to move the IMS PDU to New Radio (NR) by sending a PDU Establishment Request with an Existing PDU type. The request signifies the UE's [102] intention to maintain the continuity of the ongoing PDU session during the
20 transition from a WLAN network to an NR network, which is part of the 5G system.
[0080] At step 324, the AMF [106] attempts to locate the SMF [108] where the IMS PDU Session was established through WLAN access.
25 [0081] At step 326,, if the AMF [106] determines that the SMF [108] for the PDU ID is not found.
[0082] At step 328, if the PDU ID is not found, the method [300] includes initiating a new PDU Session Establishment procedure towards the SMF [108]. 30
[0083] At step 330, the SMF [108] is found for the PDU ID.
[0084] At step 332, if the SMF [108] is found for the PDU ID, the AMF [106] continues with the handover procedure with the identified SMF [108], ensuring the
22

5 UE’s [102] PDU session is maintained without interruption thereby maintaining service continuity and quality, as the established PDU session is seamlessly transitioned to the NR network.
[0085] Referring to FIG. 4, an exemplary method flow diagram [400] illustrating 10 methods and systems for performing handover from WLAN to New Radio (NR) in a wireless network, in accordance with exemplary embodiments of the present disclosure. As shown in FIG. 4, the method [400] implemented by the system [200], or the network node (such as the AMF [106]) starts at step [302].
15 [0086] At step [404], the method [400] as disclosed by the present disclosure comprises receiving, from a user equipment (UE) [102], a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier (PDU ID) of an existing PDU session on a first type of network. The receiving unit [202] is designed to handle requests that
20 specifically indicate the continuation of an existing PDU session by including the PDU ID associated with that session. In scenarios such as handovers, where the UE [102] moves from a first type of network, like a Wireless Local Area Network (WLAN), to a second type of network, such as a New Radio (NR) Access Network the inclusion of the PDU ID in the request helps the network node to identify the
25 specific PDU session that the UE [102] intends to maintain across different network types. Furthermore, the receiving unit [202] facilitates in ensuring seamless connectivity for the UE [102] during network handover. By accurately receiving and processing the PDU session establishment request, the receiving unit [202] enables the network node to take appropriate actions to continue the existing PDU
30 session or initiate a new session, if necessary, thereby enhancing the overall user experience.
[0087] Next, at step [406], the method [400] as disclosed by the present disclosure comprises identifying, by the network node, an existing network node
23

5 corresponding to the PDU ID tagged in the PDU session establishment request. After receiving the establishment request from the UE [102], the network node, such as AMF [106] identifies an existing network node, such as, Session Management Function (SMF) [108] corresponding to the PDU ID tagged in the PDU establishment request, where the IMS PDU Session was established through
10 WLAN access. The identifying unit [204] compares the PDU ID provided in the request with a database or registry of existing PDU sessions managed by various network nodes. When a match is found, the identifying unit [204] determines the specific network node associated with that PDU session to ensure that the correct network node is identified for the continuation or modification of the PDU session,
15 thereby facilitating seamless connectivity for the UE [102] as it transitions between different types of networks. If the existing network node (such as existing SMF [108]) is successfully identified, the network node (such as AMF [106]) can proceed with the appropriate actions to maintain or modify the PDU session as requested by the UE [102]. However, if the identification fails, the network node (such as AMF
20 [106]) can take alternative measures, such as initiating a new PDU session establishment procedure via a target network node, to ensure continuity of service for the UE [102]. This flexibility in response enhances the network's ability to adapt to various scenarios and maintain a high level of service quality
25 [0088] Next, at step [408], the method [400] as disclosed by the present disclosure comprises initiating, by the network node, a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID. The network node, AMF [106] node initiates a new PDU establishment procedure via a target network node, such
30 as new SMF node [108A] based on a failure of the identification of the existing network node, SMF node [108] corresponding to the PDU ID. In an exemplary aspect, the AMF node [106] initiates a new PDU session establishment procedure towards new SMF node [108A] in an event that existing SMF [108] for the tagged PDU ID given in PDU Establishment request from UE [102] is not found. In another
24

5 exemplary aspect, the AMF node [106] continues performing the handover procedure with the obtained SMF [108] in an event that SMF [108] for the tagged PDU ID given in PDU Establishment request from UE [102] is found.
[0089] The initiating unit [206] operates by triggering the establishment of a new 10 PDU session with the target network node, when the identifying unit [204] fails to match the PDU ID with an existing network node to ensure that the UE [102] can still establish a PDU session and maintain connectivity, even if the existing network node [such as SMF [108] is unavailable or cannot be identified for some reason. Furthermore, the initiating unit [206] facilitates in maintaining the quality of service 15 for the UE [102] during network transitions, such as handovers from a WLAN to an NR Access Network. By initiating a new PDU session establishment procedure, the initiating unit [206] helps to prevent service interruptions and call failures that might occur due to the inability to identify the existing network node.
20 [0090] In an example, a user with a smartphone (UE [102]) that is currently connected to a coffee shop's WLAN network where they have an ongoing Voice over Internet Protocol (VoIP) call running over an IMS PDU session. As they leave the coffee shop, they move out of the WLAN coverage and their smartphone automatically attempts to switch the call to the NR network provided by their
25 cellular service. Upon this action, the smartphone sends a PDU session establishment request to the network node, which in this case is the Access and Mobility Management Function (AMF [106]). This request includes the PDU ID that was being used for the VoIP call on the WLAN network. The AMF [106] receives this request and looks for the SMF [108] that was handling the PDU session
30 for the WLAN network. However, suppose the AMF [106] cannot find a matching SMF [108] because the SMF is offline or the PDU ID mapping is outdated. The traditional approach would be to send a failure message to the smartphone, leading to the call dropping. This situation leads to a poor user experience. Instead, in the present disclosure, the AMF [106] will initiate a new PDU session establishment
25

5 procedure. The AMF [106] selects a new SMF (which could be the same or different from the one used in WLAN) to set up a new IMS PDU session for the NR network. The process is seamless to the user, who notices little to no interruption in their VoIP call as they switch from WLAN to NR coverage. Furthermore, if the AMF [106] successfully identifies the original SMF [108] that facilitated the PDU session
10 over WLAN, it proceeds to perform the handover by connecting with the identified SMF and transitioning the PDU session from the WLAN to the NR network. In either case, the call does not drop, and the service continues uninterrupted.
[0091] Thereafter, the method [400] terminates at step [410].
15
[0092] As is evident from the above, the present disclosure provides a technically advanced solution for performing handover from WLAN to New Radio (NR) in a wireless network. The proposed invention reduces the time of IMS PDU not being in established and thereby user does not face call failures. Further, the present
20 disclosure prevents failure of call of the UE when a handover takes places from the WLAN to NR in a wireless communication network. With the help of the features of the present disclosure, the AMF, instead of sending a negative response, attempt into an initial PDU establishment which prevent the reattempting of handover process, saves time, prevent delays during the handover process.
25
[0093] FIG. 5 illustrates an exemplary block diagram of a computer device [500] [also referred to herein as a computer system] upon which an embodiment of the present disclosure may be implemented. In an implementation, the computing device implements the method for performing handover from WLAN to New Radio
30 (NR) in a wireless network using the system [200]. In another implementation, the computing device itself implements the method for performing handover from WLAN to New Radio (NR) in a wireless network 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.
26

5 [0094] The computer system [500] encompasses a wide range of electronic devices capable of processing data and performing computations. Examples of computer system [500] include, but are not limited only to, personal computers, laptops, tablets, smartphones, servers, and embedded systems. The devices may
10 operate independently or as part of a network and can perform a variety of tasks such as data storage, retrieval, and analysis. Additionally, computer system [500] may include peripheral devices, such as monitors, keyboards, and printers, as well as integrated components within larger electronic systems, showcasing their versatility in various technological applications.
15
[0095] 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
20 include a main memory [506], such as a random-access memory (RAM), or other dynamic 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
25 instructions, when stored in non-transitory storage media accessible to the processor [504], render the 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
30 instructions for the processor [504].
[0096] 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
27

5 display [512], such as a cathode ray tube (CRT), for displaying information to a computer user. An 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 controller [516], such as a mouse, a trackball, or cursor direction keys, for
10 communicating direction information and command selections to the processor [504], and for controlling cursor movement on the display [512]. This 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.
15 [0097] The computer system [500] may implement the techniques described herein using 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
20 [500] in response to the processor [504] executing one or more sequences of one or 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
25 herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions.
[0098] The computer system [500] also may include a communication interface [518] coupled to the bus [502]. The communication interface [518] provides a two-30 way 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
28

5 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.
10
[0099] 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
15 Internet Service Provider (ISP) [526], the Host [524], 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.
20 [0100] The computing device [500] encompasses a wide range of electronic devices capable of processing data and performing computations. Examples of computing device [500] include, but are not limited only to, personal computers, laptops, tablets, smartphones, servers, and embedded systems. The devices may operate independently or as part of a network and can perform a variety of tasks
25 such as data storage, retrieval, and analysis. Additionally, computing device [500] may include peripheral devices, such as monitors, keyboards, and printers, as well as integrated components within larger electronic systems, showcasing their versatility in various technological applications.
30 [0101] FIG. 6 illustrates an exemplary sequence diagram for performing handover from WLAN to New Radio (NR) in a wireless network, in accordance with exemplary embodiments of the present disclosure.
[0102] At step S1, the User Equipment (UE) [102] initiates a Protocol Data Unit 35 (PDU) session establishment request. The request contains a PDU Identifier (PDU
29

5 ID) associated with an existing PDU session on a first type of network, such as a Wireless Local Area Network (WLAN) [602].
[0103] At step S2, the AMF [106] extracts the PDU ID from the received request to identify the appropriate SMF [108] responsible for the existing PDU session on 10 the first network.
[0104] At step S3, the AMF attempts to find the SMF [108] that is responsible for
the existing PDU session using the PDU ID provided. This involves looking up the
mapping of the PDU ID to the SMF [108].
15
[0105] At step S4, if the AMF [106] finds SMF1 [108A], the AMF initiates the
PDU session established with the SMF1 [108A].
[0106] At step S5, if the AMF [106] fails to identify the existing SMF 20 corresponding to the PDU ID (possibly due to various reasons such as network issues or mapping errors), the AMF [106] initiates a new PDU session establishment procedure i.e., selecting a new SMF, such as SMF2 [108B], to facilitate the establishment of a new PDU session.
25 [0107] At step S6, the new connection is established between the UE and the new SMF, thus successfully transitioning the PDU session from the first type of network (WLAN) to the second type of network (New Radio, NR).
[0108] Yet another aspect of the present disclosure, a non-transitory computer-30 readable storage medium storing instruction for performing handover from WLAN to NR is disclosed. The instructions include executable code which, when executed by one or more units of a system, may cause a receiving unit [202] to receive, from a user equipment (UE) [102], a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier 35 (PDU ID) of an existing PDU session on a first type of network; an identifying unit
30

5 [204] to identify an existing network node corresponding to the PDU ID tagged in the PDU session establishment request; and an initiating unit [206] to initiate a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID.
10 [0109] Further, in accordance with the present disclosure, it is to be acknowledged that the functionality described for the various the components/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
15 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.
20
[0110] Further, in accordance with the present disclosure, it is to be acknowledged that the functionality described for the various the components/units can be implemented interchangeably. While specific embodiments may disclose a particular functionality of these units for clarity, it is recognized that various
25 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
30 of the present disclosure.
[0111] 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
31

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 that the foregoing descriptive matter to be implemented is illustrative and non-limiting.

We Claim:
1. A method implemented by a network node, the method comprising:
receiving, from a user equipment (UE) [102], a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier (PDU ID) of an existing PDU session on a first type of network;
identifying, by the network node, an existing network node corresponding to the PDU ID tagged in the PDU session establishment request; and
initiating, by the network node, a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID.
2. The method as claimed in claim 1, wherein the network node is an Access and Mobility Management Function (AMF) [106].
3. The method as claimed in claim 1, wherein the existing network node is an existing Session Management Function (SMF) [108] responsible for facilitating the existing PDU session on the first type of network.
4. The method as claimed in claim 3, wherein failure of the identification of the existing network node corresponding to the PDU ID is based on a failure in mapping of the existing SMF [108] for the received PDU ID
5. The method as claimed in claim 1, wherein the target network node is a new SMF to initiate the new PDU session establishment procedure of the UE with a second type of network.
6. The method as claimed in claim 1 further comprises:

performing, by the network node, a handover of the UE from the first type of network to a second type of network based on an identification of the existing network node corresponding to the tagged PDU ID.
7. The method as claimed in claim 6, wherein the first type of network is a wireless local-area network (WLAN) and the second type of network is a New Radio (NR) Access Network.
8. A network node comprising:
a receiving unit [202] configured to receive, from a user equipment (UE) [102], a Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier (PDU ID) of an existing PDU session on a first type of network;
an identifying unit [204] configured to identify an existing network node corresponding to the PDU ID tagged in the PDU session establishment request; and
an initiating unit [206] configured to initiate a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID.
9. The network node as claimed in claim 8, wherein the network node is an Access and Mobility Management Function (AMF) [106].
10. The network node as claimed in claim 8, wherein the existing network node is an existing Session Management Function (SMF) [108] responsible for facilitating the existing PDU session on the first type of network.
11. The network node as claimed in claim 10, wherein failure of the identification of the existing network node corresponding to the PDU ID is based on a failure in mapping of the existing SMF [108] for the received PDU ID.

12. The network node as claimed in claim 8, wherein the target network node is a new SMF to initiate the new PDU session establishment procedure of the UE [102] with a second type of network.
13. The network node as claimed in claim 8 further comprises:
a processing unit [208] configured to perform a handover of the UE [102] from the first type of network to a second type of network based on an identification of the existing network node corresponding to the tagged PDU ID.
14. The network node as claimed in claim 13, wherein the first type of network is a wireless local-area network (WLAN) and the second type of network is a New Radio (NR) Access Network.
15. A non-transitory computer-readable storage medium storing instruction for performing handover from WLAN to New Radio (NR), 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 Protocol Data Unit (PDU) session establishment request, wherein the PDU session establishment request comprises a PDU Identifier (PDU ID) of an existing PDU session on a first type of network;
an identifying unit [204] to identify an existing network node corresponding to the PDU ID tagged in the PDU session establishment request; and
an initiating unit [206] to initiate a new PDU session establishment procedure via a target network node based on a failure of the identification of the existing network node corresponding to the PDU ID.