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 CLEANUP OF NETWORK RESOURCES AFTER HANDOVER PROCEDURE”
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 CLEANUP OF NETWORK RESOURCES
AFTER HANDOVER PROCEDURE
FIELD OF THE DISCLOSURE
10 [0001] The present disclosure relates generally to the field of wireless communication system. More particularly, the present disclosure relates to method and system for cleanup of network resources after handover procedure.
BACKGROUND
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[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
20 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
25 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
30 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
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5 technology has become more advanced, sophisticated, and capable of delivering more services to its users.
[0004] Existing solutions in the art of network resource management, particularly in the context of handover procedures in 5G and 4G networks, often
10 face challenges related to the efficient release of network resources when a User Equipment (UE) moves from one network to another. For example, during a handover from a 5G network to a 4G network or from one 5G network to another, the Access and Mobility Management Function (AMF) is expected to receive a deregistration request from the Unified Data Management (UDM) unit to release
15 the resources allocated to the UE. However, due to potential issues in the network or at the UDM, this deregistration request may not reach the AMF in a timely manner or at all. As a result, the resources allocated for the UE at the AMF, Policy Control Function (PCF), and Session Management Function (SMF) units may remain occupied unnecessarily, leading to inefficiencies and reduced network
20 capacity.
[0005] Moreover, existing standards do not provide a clear solution for the scenario where the UDM-initiated deregistration request fails to reach the AMF. This lack of guidance leaves a gap in the network's ability to handle such situations 25 effectively, resulting in potential resource wastage and suboptimal network performance. Consequently, there is a need for improved mechanisms to ensure the timely release of network resources following a handover procedure, especially in cases where the expected deregistration request from the UDM is not received.
30 [0006] Thus, there exists an imperative need in the art to provide an efficient system and method for cleanup of network resources after handover procedure.
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5 OBJECTS OF THE INVENTION
[0007] Some of the objects of the present disclosure, which at least one embodiment disclosed herein satisfies are listed herein below.
10 [0008] It is an object of the present disclosure to provide a system and method for cleanup of network resources after handover procedure.
[0009] It is another object of the present disclosure to provide a system and method for cleanup of network resources after handover procedure that ensures 15 timely release of network resources allocated to a User Equipment (UE) in the event that a deregistration request from the Unified Data Management (UDM) unit is not received by the Access and Mobility Management Function (AMF) unit within a predetermined boundary time.
20 [0010] It is another object of the present disclosure to provide a system and method for cleanup of network resources after handover procedure that initiates a guard timer after a successful handover of the UE from a source network to a target network, thereby monitoring for the receipt of a deregistration request within a set timeframe.
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[0011] It is another object of the present disclosure to provide a system and method for cleanup of network resources after handover procedure that triggers a cleanup procedure for releasing the set of network resources allocated at the AMF unit, Session Management Function (SMF) unit, and Policy Control Function (PCF)
30 unit in the absence of the deregistration request before the expiry of the guard timer.
[0012] It is another object of the present disclosure to provide a system and method for cleanup of network resources after handover procedure that enhances
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5 network efficiency by preventing unnecessary resource allocation and increasing network capacity by ensuring that resources are only occupied by active UEs.
[0013] It is another object of the present disclosure to provide a system and method for cleanup of network resources after handover procedure that is adaptable 10 to different network configurations and handover scenarios, including handovers between 4G and 5G networks as well as within 5G networks where the AMF is also changed.
[0014] It is another object of the present disclosure to provide a system and 15 method for cleanup of network resources after handover procedure that maintains network resources and session continuity if the UDM deregistration request is received before the expiration of the guard timer, thereby ensuring uninterrupted service for the UE.
20 [0015] It is another object of the present disclosure to provide a system and method for cleanup of network resources after handover procedure that is configurable, allowing network operators to set the guard timer based on the expected time frame within which the deregistration request should be received post-handover.
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SUMMARY OF THE DISCLOSURE
[0016] This section is provided to introduce certain aspects of the present disclosure in a simplified form that are further described below in the detailed 30 description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
[0017] According to an aspect of the present disclosure, a method for managing network resources subsequent to a handover procedure in a communication
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5 network, the method comprising initiating, by an access and mobility management function (AMF) unit, a guard timer after successful handover of a User Equipment (UE) from a source network to a target network. The method further includes monitoring, by the AMF unit, for a deregistration request from a Unified Data Management (UDM) unit for the UE within a predetermined boundary time set by
10 the guard timer. Thereafter, the method further includes initiating, by the AMF unit, a cleanup procedure for a set of network resources, corresponding to the handover, allocated to the UE in absence of receiving the deregistration request from the UDM unit before expiry of the guard timer, wherein the cleanup procedure comprises releasing the set of network resources allocated, for the handover, at the AMF unit,
15 Session Management Function (SMF) unit, and Policy Control Function (PCF) unit.
[0018] In an aspect, the method comprises invoking, by the AMF unit, a Release session management (SM) Context service operation towards the SMF unit to release a set of protocol data unit (PDU) sessions for the UE as part of the cleanup 20 procedure.
[0019] In an aspect, the guard timer is configured based on a predetermined value that corresponds to an expected time frame within which the deregistration request from the UDM unit should be received post-handover.
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[0020] In an aspect, the method comprises initiating, by the AMF unit, a UE Policy Association termination procedure to delete UE policy and access and mobility (AM) policy associated resources with the PCF unit as part of the cleanup procedure.
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[0021] In an aspect, the method comprises halting, by the AMF unit, the cleanup procedure if the deregistration request from the UDM unit is received before the expiry of the guard timer.
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5 [0022] In an aspect, the method comprises transmitting, by the AMF unit, a deregistration service operation towards the UDM unit to remove the association with the UE following the resource cleanup procedure.
[0023] In an aspect, the guard timer is configurable. 10
[0024] In an aspect, the method comprises maintaining, by the AMF unit, the network resources and session continuity if the UDM deregistration request is received before the expiration of the guard timer.
15 [0025] In an aspect, the source network comprises at least one of a Next Generation Radio Access Network (NGRAN) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and the target network comprises at least one of the NGRAN and the E-UTRAN.
20 [0026] Another aspect of the present disclosure comprises a system for managing network resources subsequent to a handover procedure in a communication network, the system comprising an access and mobility management function (AMF) unit comprising a processing unit configured to initiate a guard timer after successful handover of a User Equipment (UE) from a
25 source network to a target network. The AMF unit further comprises a monitoring unit configured to monitor for a deregistration request from a Unified Data Management (UDM) unit for the UE within a predetermined boundary time set by the guard timer; and the AMF unit further comprises the processing unit configured to initiate a cleanup procedure for a set of network resources, corresponding to the
30 handover, allocated to the UE in absence of receiving the deregistration request from the UDM unit before expiry of the guard timer, wherein the cleanup procedure comprises releasing the set of network resources allocated, for the handover, at the AMF unit, Session Management Function (SMF) unit, and Policy Control Function (PCF) unit.
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[0027] Yet another aspect of the present disclosure, a non-transitory computer-readable storage medium storing instruction managing network resources subsequent to a handover procedure in a communication network is disclosed. The storage medium comprising executable code which, when executed by one or more
10 units of a system, causes: a processing unit configured to initiate a guard timer after successful handover of a User Equipment (UE) from a source network to a target network; a monitoring unit configured to monitor for a deregistration request from a Unified Data Management (UDM) unit for the UE within a predetermined boundary time set by the guard timer; and the processing unit configured to initiate
15 a cleanup procedure for a set of network resources, corresponding to the handover, allocated to the UE in absence of receiving the deregistration request from the UDM unit before expiry of the guard timer, wherein the cleanup procedure comprises releasing the set of network resources, for the handover, at the AMF unit, Session Management Function (SMF) unit, and Policy Control Function (PCF) unit.
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BRIEF DESCRIPTION OF DRAWINGS
[0028] The accompanying drawings, which are incorporated herein, and constitute a part of this disclosure, illustrate exemplary embodiments of the
25 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
30 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.
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5 [0029] FIG. 1 illustrates an exemplary block diagram representation of 5th generation core (5GC) network architecture, in accordance with exemplary embodiment of the present disclosure.
[0030] FIG. 2 illustrates an exemplary block diagram of a system for cleanup of network resources after handover procedure, in accordance with exemplary
10 embodiments of the present disclosure.
[0031] FIG. 3 illustrates an exemplary sequence diagram illustrating call flow diagram indicating the process for managing network resources subsequent to a handover procedure in a communication network, in accordance with exemplary 15 embodiments of the present disclosure.
[0032] FIG. 4 illustrates an exemplary method flow diagram indicating the process for managing network resources subsequent to a handover procedure in a communication network, in accordance with exemplary embodiments of the present 20 disclosure.
[0033] FIG. 5 illustrates an exemplary block diagram of a computing device upon which an embodiment of the present disclosure may be implemented.
25 [0034] The foregoing shall be more apparent from the following more detailed description of the disclosure.
DETAILED DESCRIPTION
30 [0035] 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 may each be used independently of one
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5 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.
[0036] The ensuing description provides exemplary embodiments only, and is 10 not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in 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 15 of the disclosure as set forth.
[0037] 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 20 specific details. For example, circuits, systems, processes, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail.
[0038] Also, it is noted that individual embodiments may be described as a 25 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 may be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed but could have additional 30 steps not included in a figure.
[0039] 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
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5 aspect or design described herein as “exemplary” and/or “demonstrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it meant to preclude equivalent exemplary structures and techniques known to those of ordinary skill in the art. Furthermore, to the extent that the terms “includes,” “has,” “contains,” and other similar words are used in either the detailed
10 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.
[0040] As used herein, a “processing unit” or “processor” or “operating
15 processor” includes one or more processors, wherein processor refers to any logic circuitry for processing instructions. A processor may be a general-purpose processor, a 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
20 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 the present disclosure. More specifically, the processor or processing unit is a hardware processor.
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[0041] As used herein, “a user equipment”, “a user device”, “a smart-user-device”, “a smart-device”, “an electronic device”, “a mobile device”, “a handheld device”, “a wireless communication device”, “a mobile communication device”, “a communication device” may be any electrical, electronic and/or computing device
30 or equipment, capable of implementing the features of the present disclosure. The user equipment/device may include, but is not limited to, a mobile phone, smart phone, laptop, a general-purpose computer, desktop, personal digital assistant, tablet computer, wearable device or any other computing device which is capable of implementing the features of the present disclosure. Also, the user device may
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5 contain at least one input means configured to receive an input from at least one of a transceiver unit, a processing unit, a storage unit, a detection unit and any other such unit(s) which are required to implement the features of the present disclosure.
[0042] As used herein, “storage unit” or “memory unit” refers to a machine or 10 computer-readable medium including any mechanism for storing information in a form readable by a computer or similar machine. For example, a computer-readable medium includes read-only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory devices or other types of machine-accessible storage media. The storage unit stores at least the data 15 that may be required by one or more units of the system to perform their respective functions.
[0043] As portable electronic devices and wireless technologies continue to improve and grow in popularity, the advancing wireless technologies for data
20 transfer are also 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 generation (4G), and now fifth generation (5G),
25 and more such generations are expected to continue in the forthcoming time.
[0044] 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 30 base stations, which are responsible for providing the wireless connection. Further, each RAT has its own set of protocols and standards for communication, which define the frequency bands, modulation techniques, and other parameters used for transmitting and receiving data. Examples of RATs include GSM (Global System for Mobile Communications), CDMA (Code Division Multiple Access), UMTS
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5 (Universal Mobile Telecommunications System), LTE (Long-Term Evolution), and 5G. The choice of RAT depends on a variety of factors, including the network infrastructure, the available spectrum, and the mobile device's/device's capabilities. Mobile devices often support multiple RATs, allowing them to connect to different types of networks and provide optimal performance based on the available network
10 resources. The invention herein relates to the situations when the user equipment (UE) operates in the fifth generation (5G) communication system.
[0045] As discussed in the background section, existing solutions in the art of network resource management, particularly in the context of handover procedures
15 in 5G and 4G networks, often face challenges related to the efficient release of network resources when a User Equipment (UE) moves from one network to another. For example, during a handover from a 5G network to a 4G network or from one 5G network to another, the Access and Mobility Management Function (AMF) is expected to receive a deregistration request from the Unified Data
20 Management (UDM) unit to release the resources allocated to the UE. However, due to potential issues in the network or at the UDM unit, this deregistration request may not reach the AMF in a timely manner or at all. As a result, the resources allocated for the UE at the AMF, Policy Control Function (PCF), and Session Management Function (SMF) units may remain occupied unnecessarily, leading to
25 inefficiencies and reduced network capacity. Moreover, existing standards do not provide a clear solution for the scenario where the UDM-initiated deregistration request fails to reach the AMF. This lack of guidance leaves a gap in the network's ability to handle such situations effectively, resulting in potential resource wastage and suboptimal network performance. Consequently, there is a need for improved
30 me chanis ms to ensure the tim e l y r elease o f network resources f ollowing a handover procedure, especially in cases where the expected deregistration request from the UDM unit is not received.
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5 [0046] To overcome these and other inherent problems in the art, the present disclosure proposes a solution of implementing a guard timer within the AMF unit that is initiated following the successful handover of a User Equipment (UE) from a source network to a target network. The guard timer serves as a contingency mechanism to ensure the timely release of network resources by setting a
10 predetermined boundary time for a deregistration request from the Unified Data Management (UDM) unit to be received. If the UDM deregistration request is not received within this boundary time, the AMF unit proactively initiates a cleanup procedure for the network resources allocated to the UE. This cleanup procedure includes releasing the network resources held at the AMF unit, as well as
15 coordinating the release of the UE's session and policy association resources with the Session Management Function (SMF) unit and the Policy Control Function (PCF) unit respectively. The invention's approach effectively mitigates the risk of network resources remaining unnecessarily occupied due to the absence of a deregistration request, which could arise from various issues such as network
20 failures or delays at the UDM unit. By allowing the guard timer to be configurable, the system can be tailored to different network environments and operational scenarios, offering flexibility and adaptability. Furthermore, if a deregistration request is received before the guard timer expires, the cleanup procedure is halted, thereby maintaining the allocated resources and session continuity for the UE.
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[0047] By addressing the absence of a clear standard for handling situations where a UDM deregistration request fails to reach the AMF, the invention fills a critical gap in the network's resource management capabilities. It provides an end-to-end user resource cleanup for nodes within the 5G Core (5GC), namely the AMF,
30 PCF, SMF, and UDM unit, thus avoiding resource wastage and enhancing overall network performance. The proposed invention not only ensures an efficient cleanup of resources post-handover but also supports the network's capacity to seamlessly manage handovers between different generations of network technology, such as 4G and 5G.
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[0048] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. [0049] FIG. 1 illustrates an exemplary block diagram representation of 5th generation core (5GC) network architecture [100], in accordance with exemplary
10 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 as, an access and mobility management function (AMF) [106], a Session Management Function (SMF) unit [108], a Service Communication Proxy (SCP)
15 [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 Network Repository Function (NRF) [120], a Policy Control Function (PCF) [122], a Unified Data Management (UDM) [124], an application function (AF) [126], a
20 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.
[0050] The User Equipment (UE) [102] interfaces with the network via the 25 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 proxy (SCP) [110] routes and manages communication between network services, enhancing efficiency and security, and the Authentication Server 30 Function (AUSF) [112] handles user authentication; the 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
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5 applications, and maintain network function 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
10 external internet resources; 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.
15 [0051] 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). It consists of radio base stations and the radio access technologies that enable wireless communication.
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[0052] 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 25 handovers and paging.
[0053] 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
30 (UPF) for data forwarding and handles IP address allocation and QoS enforcement.
[0054] Service Communication Proxy (SCP) [110] is a network function in the 5G core network that facilitates communication between other network
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5 functions by providing a secure and efficient messaging service. It acts as a mediator for service-based interfaces.
[0055] Authentication Server Function (AUSF) [112] is a network function in the 5G core responsible for authenticating UEs during registration and providing 10 security services. It generates and verifies authentication vectors and tokens.
[0056] 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 15 the slices for which they are authorized.
[0057] 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. 20
[0058] 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.
25 [0059] Network Repository Function (NRF) [120] is a network function that acts as a central repository for information about available network functions and services. It facilitates the discovery and dynamic registration of network functions.
[0060] Policy Control Function (PCF) [122] is a network function 30 responsible for policy control decisions, such as QoS, charging, and access control, based on subscriber information and network policies.
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5 [0061] Unified Data Management (UDM) [124] is a network function that centralizes the management of subscriber data, including authentication, authorization, and subscription information.
[0062] Application Function (AF) [126] is a network function that represents 10 external applications interfacing with the 5G core network to access network capabilities and services.
[0063] User Plane Function (UPF) [128] is a network function responsible for handling user data traffic, including packet routing, forwarding, and QoS 15 enforcement.
[0064] 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 but are not limited to Internet services, private data network related 20 services.
[0065] FIG. 2 illustrates an exemplary block diagram of a system [200] for cleanup of network resources after handover procedure, in accordance with exemplary embodiments of the present disclosure. As shown in FIG. 2, the system
25 [200] includes a processing unit [202], a monitoring unit [204], and a transmitting unit [206], 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. 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
30 any such numbers of said units, as required to implement the features of the present disclosure. In an embodiment, the system [200] may be incorporated in the AMF unit [106].
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5 [0066] The system [200] includes a processing unit [202] configured to initiate a guard timer after the successful handover of a User Equipment (UE) [102] from a source network to a target network. The source network could be either a Next Generation Radio Access Network (NGRAN) or an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and similarly, the target network could be one
10 of these networks as well. Once the UE [102] has successfully transitioned from the source network to the target network, the processing unit [202] within the Access and Mobility Management Function (AMF) unit [106] is responsible for initiating a guard timer. This timer sets a predetermined boundary time within which the AMF unit [106] expects to receive a deregistration request from the Unified Data
15 Management (UDM) unit [124] for the UE [102]. The initiation of the guard timer by the processing unit [202] facilitates in ensuring that network resources are not unnecessarily held up due to potential delays or failures in receiving the deregistration request from the UDM unit [124].
20 [0067] The system [200] includes the monitoring unit [204] communicatively coupled to the processing unit [202]. The monitoring unit [204] is configured to monitor for a deregistration request from a Unified Data Management (UDM) unit [124] for the User Equipment (UE) [102] within a predetermined boundary time set by the guard timer. The predetermined boundary time is determined based on the
25 configuration of the guard timer, which is initiated by the processing unit [202] following a successful handover of the UE [102] from a source network to a target network. The monitoring unit [204] continuously observes the incoming communication to the Access and Mobility Management Function (AMF) unit [106] during this boundary time, specifically looking for a signal or message that
30 indicates the UDM unit [124] has sent a deregistration request for the UE [102]. If such a request is received within the set time frame, the monitoring unit [204] informs the processing unit [202], which then takes appropriate action to halt any cleanup procedures that might have been initiated due to the absence of the deregistration request. This ensures that network resources are managed efficiently
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5 and are not prematurely released, maintaining network stability and resource optimization.
[0068] The processing unit [202] is further configured to initiate a cleanup procedure for a set of network resources allocated to the User Equipment (UE)
10 [102] in the absence of receiving the deregistration request from the Unified Data Management (UDM) unit [124] before the expiry of the guard timer. The cleanup procedure facilitates in managing network resources efficiently, particularly in scenarios where the expected deregistration request from the UDM unit [124] does not reach the Access and Mobility Management Function (AMF) unit [106] within
15 the predetermined boundary time. The absence of the deregistration request signifies that the resources allocated to the UE [102] are potentially no longer required, as the UE [102] may have successfully transitioned to the target network.
[0069] The cleanup procedure comprises releasing the set of network resources 20 allocated at various units within the communication network. Specifically, the processing unit [202] within the AMF unit [106] takes the lead in coordinating this resource release process. The resources to be released include those allocated at the AMF unit [106] itself, which may involve clearing the user context and any associated session information. Additionally, the processing unit [202] 25 communicates with the Session Management Function (SMF) unit [108] to release the Protocol Data Unit (PDU) sessions that were established for the UE [102]. This involves invoking a Release Session Management (SM) Context service operation towards the SMF unit [108].
30 [0070] Furthermore, the processing unit [202] coordinates with the Policy Control Function (PCF) unit [122] to terminate any policy associations and release access and mobility policy resources that were associated with the UE [102]. This step ensures that any policy rules or settings applied to the UE's sessions are appropriately cleared.
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[0071] By initiating this cleanup procedure, the processing unit [202] ensures that network resources are not unnecessarily occupied by UEs that have already transitioned to a different network, thereby optimizing the utilization of network resources and maintaining network efficiency. This proactive approach to resource
10 management is particularly important in dynamic network environments where handovers and network transitions are frequent.
[0072] The processing unit [202] is further configured to invoke a Release session management (SM) Context service operation towards the Session
15 Management Function (SMF) unit [108] to release a set of Protocol Data Unit (PDU) sessions for the User Equipment (UE) [102] as part of the cleanup procedure. The resources allocated for the PDU sessions are released when they are no longer needed, thereby optimizing resource utilization and preventing unnecessary resource allocation.
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[0073] Additionally, the processing unit [202] is configured to configure the guard timer based on a predetermined value that corresponds to an expected time frame within which the deregistration request from the Unified Data Management (UDM) unit [124] should be received post-handover. The expected time frame may
25 range from a few milliseconds to several seconds, depending on the network's operational parameters and conditions. The configuration ensures that the system has a defined window of time to wait for the deregistration request before initiating the cleanup procedure, allowing for flexibility and adaptability to different network conditions and scenarios.
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[0074] The processing unit [202] is also configured to initiate a UE Policy Association termination procedure to delete UE policy and access and mobility (AM) policy associated resources with the Policy Control Function (PCF) unit [122] as part of the cleanup procedure. This action ensures that any policies applied to the
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5 UE's sessions are appropriately terminated, and the associated resources are released.
[0075] Furthermore, the processing unit [202] is configured to halt the cleanup procedure if the deregistration request from the UDM unit [124] is received before 10 the expiry of the guard timer. This capability allows the system to stop the resource release process if the deregistration request arrives within the expected time frame, ensuring that resources are not unnecessarily released.
[0076] The guard timer within the system is configurable, allowing for 15 flexibility in setting the time frame based on network conditions, operator preferences, or other factors. This configurability ensures that the system can adapt to various operational requirements.
[0077] Lastly, the processing unit [202] is configured to maintain the network 20 resources and session continuity if the UDM unit [124] deregistration request is received before the expiration of the guard timer. This ensures that the UE's sessions and associated resources are preserved when the deregistration request is timely, maintaining service continuity for the user.
25 [0078] The transmitting unit [206] is configured to transmit a deregistration service operation towards the Unified Data Management (UDM) unit [124] to remove the association with the User Equipment (UE) [102] following the resource cleanup procedure. Once the cleanup procedure has been initiated and completed by the processing unit [202], the transmitting unit [206] takes the responsibility of
30 formally deregistering the UE [102] from the UDM unit [124]. This deregistration is necessary to ensure that the UDM unit [124] is aware that the UE [102] is no longer associated with the network resources that were previously allocated to it.
22

5 [0079] The deregistration service operation is an important step in the overall process as it ensures that the UDM unit [124] updates its records to reflect the removal of the UE [102] from its list of registered devices. This prevents any future confusion or errors that might arise from the UDM unit [124] assuming that the UE [102] is still associated with the network resources that have been released. By
10 transmitting this deregistration service operation, the transmitting unit [206] helps to maintain the integrity of the network's record-keeping and ensures that the network resources are available for allocation to other UEs that might need them.
[0080] FIG. 3 illustrates an exemplary sequence diagram [300] illustrating call 15 flow diagram indicating the process for managing network resources subsequent to a handover procedure in a communication network, in accordance with exemplary embodiments of the present disclosure. As shown in FIG. 3, the sequence diagram [300] comprises the AMF unit [106], the PCF unit [122], the SMF unit [108], and the UDM unit [124]. 20
[0081] At step S1, after successful performance of a handover from 5G to 4G in a connected mode handover procedure or from a 5G to 5G N2 handover procedure where the AMF unit [106] is also getting changed. Subsequently, upon the successful handover of the UE [102], the source AMF unit [106] initiates a 25 guard timer based on a configured value. The guard timer serves as a boundary within which the AMF unit [106] expects to receive a Deregistration request from the UDM unit [124].
[0082] At step S2, UDM initiated Deregistration (such as Udm_ini _Dereg) is 30 received before the guard timeout.
[0083] At step S3, in the absence of a Deregistration request upon timer expiration, the source AMF unit [106] proactively invokes a Release SM Context service operation (such as Nsmf_PDUSession_ReleaseSMContext Request)
23

5 towards the SMF unit [108] to release any PDU sessions associated with the UE [102], effectively beginning the process of freeing up network resources that are no longer required by the UE [102].
[0084] At step S4, the SMF unit [108] processes the Release SM Context 10 request sent by the AMF, completing the necessary actions to terminate the PDU sessions associated with the UE [102]. i.e. the response (such as Nsmf_PDUSession_ReleaseSMContext) is sent from the SMF unit [108] to the AMF unit [106].
15 [0085] At step S5, The AMF unit [106] initiates the deregistration process by sending a request (such as Nudm_UECM_Deregistration) request to the UDM [124], disassociating the UE [102] from the UDM's records such that all relevant user data and session information associated with the UE [102] are properly deregistered, ensuring that the UDM no longer maintains any active association
20 with the UE [102].
[0086] At step S6, the AMF unit [106] initiates the process to terminate the Access and Mobility (AM) policy association for the UE [102]. The AMF unit [106] triggers the AM Policy Association Termination procedure, which involves 25 communicating with the Policy Control Function (PCF) to terminate any policy associations related to the UE's access and mobility within the network.
[0087] At step S7, the AMF unit [106] initiates the process to terminate the User Equipment (UE) Policy Association. The AMF unit [106] sends a termination 30 request to the Policy Control Function (PCF), which manages the policy rules and controls for the UE [102].
[0088] At step S8, the AMF unit [106] finalizes the cleanup process by removing all traces of the UE [102] from the system. The clean involves deleting
24

5 the user context, which includes any data and session information related to the UE [102], from both the in-memory storage and the database.
10 [0089] FIG. 4 illustrates an exemplary method flow diagram [400] indicating the process for managing network resources subsequent to a handover procedure in a communication network, in accordance with exemplary embodiments of the present disclosure. In an implementation, the method [400] is performed by the system [200] or the AMF unit [106]. As shown in FIG. 4, the method [400] starts
15 at step [402].
[0090] At step [404], the method [400] as disclosed by the present disclosure comprises Initiating, by an access and mobility management function (AMF) unit [106], a guard timer after successful handover of a User Equipment (UE) [102] from
20 a source network to a target network. The source network could be either a Next Generation Radio Access Network (NGRAN) or an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and similarly, the target network could be one of these networks as well. Once the UE [102] has successfully transitioned from the source network to the target network, the processing unit [202] within the Access
25 and Mobility Management Function (AMF) unit [106] is responsible for initiating a guard timer. This timer sets a predetermined boundary time within which the AMF unit [106] expects to receive a deregistration request from the Unified Data Management (UDM) unit [124] for the UE [102]. The initiation of the guard timer by the processing unit [202] is a critical step in ensuring that network resources are
30 not unnecessarily held up due to potential delays or failures in receiving the deregistration request from the UDM unit [124].
[0091] Next, at step [406], the method [400] as disclosed by the present disclosure comprises monitoring, by the AMF unit [106], for a deregistration
25

5 request from a Unified Data Management (UDM) unit [124] for the UE [102] within a predetermined boundary time set by the guard timer. The predetermined boundary time is determined based on the configuration of the guard timer, which is initiated by the processing unit [202] following a successful handover of the UE [102] from a source network to a target network. The monitoring unit [204] continuously
10 observes the incoming communication to the Access and Mobility Management Function (AMF) unit [106] during this boundary time, specifically looking for a signal or message that indicates the UDM unit [124] has sent a deregistration request for the UE [102]. If such a request is received within the set time frame, the monitoring unit [204] informs the processing unit [202], which then takes
15 appropriate action to halt any cleanup procedures that might have been initiated due to the absence of the deregistration request. This ensures that network resources are managed efficiently and are not prematurely released, maintaining network stability and resource optimization.
20 [0092] Next, at step [408], the method [400] as disclosed by the present disclosure comprises initiating, by the AMF unit [106], a cleanup procedure for a set of network resources allocated to the UE [102] in absence of receiving the deregistration request from the UDM unit [124] before expiry of the guard timer, wherein the cleanup procedure comprises releasing the set of network resources
25 allocated at the AMF unit [106], Session Management Function (SMF) unit [108], and Policy Control Function (PCF) unit [122]. The cleanup procedure is a crucial aspect of managing network resources efficiently, particularly in scenarios where the expected deregistration request from the UDM unit [124] does not reach the Access and Mobility Management Function (AMF) unit [106] within the
30 predetermined boundary time. The absence of the deregistration request signifies that the resources allocated to the UE [102] are potentially no longer required, as the UE may have successfully transitioned to the target network.
26

5 [0093] The cleanup procedure comprises releasing the set of network resources allocated at various units within the communication network. Specifically, the processing unit [202] within the AMF unit [106] takes the lead in coordinating this resource release process. The resources to be released include those allocated at the AMF unit [106] itself, which may involve clearing the user context and any
10 associated session information. Additionally, the processing unit [202] communicates with the Session Management Function (SMF) unit [108] to release the Protocol Data Unit (PDU) sessions that were established for the UE [102]. This involves invoking a Release Session Management (SM) Context service operation towards the SMF unit [108].
15
[0094] Furthermore, the processing unit [202] coordinates with the Policy Control Function (PCF) unit [122] to terminate any policy associations and release access and mobility policy resources that were associated with the UE [102]. This step ensures that any policy rules or settings applied to the UE's sessions are
20 appropriately cleared. By initiating this cleanup procedure, the processing unit [202] ensures that network resources are not unnecessarily occupied by UEs that have already transitioned to a different network, thereby optimizing the utilization of network resources and maintaining network efficiency. This proactive approach to resource management is particularly important in dynamic network environments
25 where handovers and network transitions are frequent.
[0095] Thereafter, the method [400] terminates at [410].
[0096] As is evident from the above, the present disclosure provides a 30 technically advanced solution for optimizing network nodes by cleaning network resources. The present system and a method cleans or releases network resources in all 5G nodes such as SMF, PCF, UDM and AMF, for user equipment which are no longer attached on that 5G network, if UDM initiated Deregistration does not
27

5 come to AMF. The present solution ensures that there are no unwanted resources stuck in network, hence network capacity is maintained.
[0097] FIG. 5 illustrates an exemplary block diagram of a computer system [500] upon which an embodiment of the present disclosure may be implemented.
10 In an implementation, the computing device implements the method for cleanup of network resources after handover procedure using the system [200]. In another implementation, the computing device itself implements the method for cleanup of network resources after handover procedure by using one or more units configured within the computing device, wherein said one or more units are capable of
15 implementing the features as disclosed in the present disclosure.
[0098] 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,
20 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 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
25 versatility in various technological applications.
[0099] 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 30 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 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
28

5 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 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
10 storage device coupled to the bus [502] for storing static information and instructions for the processor [504].
[0100] 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
15 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 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
20 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 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.
25
[0101] 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
30 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 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

5 memory [506] causes the processor [504] to perform the process steps described herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions.
[0102] The computer system [500] also may include a communication
10 interface [518] coupled to the bus [502]. The communication interface [518]
provides a two-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
15 corresponding type of telephone line. As another example, the communication
interface [518] may be a 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
20 data streams representing various types of information.
[0103] 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
25 transmit a requested code for an application program through the Internet [528], the Internet Service 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
[0104] Yet another aspect of the present disclosure, a non-transitory computer-readable storage medium storing instruction managing network resources subsequent to a handover procedure in a communication network is disclosed. The storage medium comprising executable code which, when executed by one or more

5 units of a system, causes: a processing unit configured to initiate a guard timer after successful handover of a User Equipment (UE) from a source network to a target network; a monitoring unit configured to monitor for a deregistration request from a Unified Data Management (UDM) unit for the UE within a predetermined boundary time set by the guard timer; and the processing unit configured to initiate
10 a cleanup procedure for a set of network resources, corresponding to the handover, allocated to the UE in absence of receiving the deregistration request from the UDM unit before expiry of the guard timer, wherein the cleanup procedure comprises releasing the set of network resources, for the handover, at the AMF unit, Session Management Function (SMF) unit, and Policy Control Function (PCF) unit.
15
[0105] 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
20 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
25 of the present disclosure.
[0106] 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 30 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.

5 We Claim:
1. A method for managing network resources subsequent to a handover procedure in a communication network, the method comprising:
initiating, by an access and mobility management function (AMF) unit [106], a guard timer after successful handover of a User Equipment (UE) 10 [102] from a source network to a target network;
monitoring, by the AMF unit [106], for a deregistration request from a Unified Data Management (UDM) unit [124] for the UE [102] within a predetermined boundary time set by the guard timer; and
initiating, by the AMF unit [106], a cleanup procedure for a set of 15 network resources, corresponding to the handover, allocated to the UE [102] in absence of receiving the deregistration request from the UDM [124] before expiry of the guard timer, wherein the cleanup procedure comprises releasing the set of network resources allocated, for the handover, at the AMF unit [106], Session Management Function (SMF) unit [108], and Policy Control 20 Function (PCF) unit [122].
2. The method as claimed in claim 1, comprises invoking, by the AMF unit
[106], a Release session management (SM) Context service operation towards
the SMF unit [108] to release a set of protocol data unit (PDU) sessions for
25 the UE [102] as part of the cleanup procedure.
3. The method as claimed in claim 1, wherein the guard timer is configured
based on a predetermined value that corresponds to an expected time frame
within which the deregistration request from the UDM unit [124] should be
30 received post-handover.

5 4. The method of claim 1, comprises initiating, by the AMF unit [106], a UE Policy Association termination procedure to delete UE policy and access and mobility (AM) policy associated resources with the PCF unit [122] as part of the cleanup procedure.
10 5. The method of claim 1, comprises halting, by the AMF unit [106], the cleanup procedure if the deregistration request from the UDM unit [124] is received before the expiry of the guard timer.
6. The method as claimed in claim 1, comprises transmitting, by the AMF unit
15 [106], a deregistration service operation towards the UDM unit [124] to
remove the association with the UE [102] following the cleanup procedure.
7. The method as claimed in claim 1, wherein the guard timer is configurable.
20 8. The method as claimed in claim 1, further comprising maintaining, by the AMF unit [106], the network resources and session continuity if the UDM [124] deregistration request is received before the expiration of the guard timer.
25 9. The method as claimed in claim 1, wherein:
the source network comprises at least one of a Next Generation Radio Access Network (NGRAN) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and
the target network comprises at least one of the NGRAN and the E-30 UTRAN.
10. A system for managing network resources subsequent to a handover procedure in a communication network, the system comprising:

5 an access and mobility management function (AMF) unit [106]
comprising:
a processing unit [202] configured to initiate a guard timer after successful handover of a User Equipment (UE) [102] from a source network to a target network;
10 a monitoring unit [204] configured to monitor for a deregistration
request from a Unified Data Management (UDM) unit [124] for the UE [102] within a predetermined boundary time set by the guard timer; and
the processing unit [202] configured to initiate a cleanup procedure for a set of network resources, corresponding to the
15 handover, allocated to the UE [102] in absence of receiving the
deregistration request from the UDM unit [124] before expiry of the guard timer, wherein the cleanup procedure comprises releasing the set of network resources, for the handover, at the AMF unit [106], Session Management Function (SMF) unit [108], and Policy Control Function
20 (PCF) unit [122].
11. The system as claimed in claim 10, wherein the processing unit [202] is
configured to invoke a Release session management (SM) Context service
operation towards the SMF unit [108] to release a set of PDU sessions for the
25 UE [102] as part of the cleanup procedure.
12. The system as claimed in claim 10, wherein the guard timer is configured
based on a predetermined value that corresponds to an expected time frame
within which the deregistration request from the UDM unit [124] should be
30 received post-handover.
13. The system as claimed in claim 10, wherein the processing unit [202] is
configured to initiate a UE Policy Association termination procedure to delete

5 UE policy and access and mobility (AM) policy associated resources with the PCF unit [122] as part of the cleanup procedure.
14. The system as claimed in claim 10, wherein the processing unit [202] is
configured to halt the cleanup procedure if the deregistration request from the
10 UDM unit [124] is received before the expiry of the guard timer.
15. The system as claimed in claim 10, comprises a transmitting unit [206]
configured to transmit a deregistration service operation towards the UDM
unit [124] to remove the association with the UE [102] following the cleanup
15 procedure.
16. The system as claimed in claim 10, wherein the guard timer is configurable.
17. The system as claimed in claim 10, wherein the processing unit [202] is 20 configured to maintain the network resources and session continuity if the
UDM unit [124] deregistration request is received before the expiration of the guard timer.
18. The system as claimed in claim 10, wherein:
25 the source network comprises at least one of a Next Generation Radio
Access Network (NGRAN) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and
the target network comprises at least one of the NGRAN and the E-UTRAN.
30 Dated this 3rd day of July 2023
(GARIMA SAHNEY)
IN/PA-1826
AGENT FOR THE APPLICANT(S)
OF SAIKRISHNA & ASSOCIATES