Methods and apparatus for handling pdu session(s) associated with area restriction for slice in a wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments herein disclose a method for handing a protocol data unit (PDU) session associated with a restricted area for a slice by an AMF entity (200). The method includes providing at least one of: a S-NSSAI into a partially allowed NSSAI and the S-NSSAI associated with a NS-AoS. Further, the method includes determining the PDU session is subjected to area restriction for the S-NSSAI based on the determination that S-NSSAI is part of at least one of the partially allowed NSSAI and the NS-AoS. Further, the method includes sending an indication to a SMF entity (300) that the PDU session is subjected to area restriction for the S-NSSAI based on the determination.

Description

METHODS AND APPARATUS FOR HANDLING PDU SESSION(S) ASSOCIATED WITH AREA RESTRICTION FOR SLICE IN A WIRELESS COMMUNICATION SYSTEM

[0001] This application is based on and derives the benefit of Indian Provisional Application 202341064688, the contents of which are incorporated herein by reference.

[0002] Embodiments disclosed herein relate to network slicing in a Third Generation Partnership Project (3GPP), and more particularly to systems and methods for ensuring that an Access Mobility Function (AMF) entity, a Session Management Function (SMF) entity and a User Equipment (UE) are correctly handling an existing Protocol Data Unit (PDU) session associated with area restriction for one slice in a fifth generation (5G) systems.

[0003] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in “Sub 6GHz” bands such as 3.5GHz, but also in “Above 6GHz” bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0004] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0005] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0006] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0007] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0008] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0009] The present disclosure relates to wireless communication systems and, more specifically, the present disclosure relates to adaptation for handling PDU session(s) associated with area restriction for slice in a wireless communication.

[0010] The principal object of embodiments herein is to disclose systems and methods for ensuring that an AMF entity, a SMF entity and a UE are correctly handling the existing Protocol Data Unit (PDU) session associated with area restriction for one slice in 5G systems.

[0011] Another object of embodiments herein is to provide that the AMF entity provides indication to the SMF entity for the established PDU session if the slice is not associated with a Partially Allowed NSSAI or a NS-AoS.

[0012] Another object of embodiments herein is to provide that the SMF entity then unsubscribes a UE mobility event notification for reporting UE presence in Area of Interest by providing S-NSSAI to the AMF entity

[0013] Another object of embodiments herein is to provide that the SMF entity always send the downlink packet for the UE.

[0014] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope thereof, and the embodiments herein include all such modifications.

[0015] Accordingly, the embodiments herein provide a method for handling a protocol data unit (PDU) session associated with a restricted area for a slice. The method includes providing, by an AMF entity, at least one of: a Single-Network Slice Selection Assistance Information (S-NSSAI) into a partially allowed NSSAI and the S-NSSAI associated with a Network Slice Area of Service (NS-AoS). Further, the method includes determining, by the AMF entity, the PDU session is subjected to area restriction for the S-NSSAI based on the determination that S-NSSAI is part of at least one of the partially allowed NSSAI and the NS-AoS. Further, the method includes sending, by the AMF entity, an indication to a SMF entity that the PDU session is subjected to area restriction for the S-NSSAI based on the determination.

[0016] In an embodiment, the method includes receiving a first message indicating that the SMF entity subscribes to a UE mobility event notification for reporting a UE presence in an area of interest by providing the S-NSSAI to the AMF entity.

[0017] In an embodiment, the method includes determining, by the AMF entity, at least one of: that the S-NSSAI is moved to an allowed NSSAI from the partially allowed NSSAI and the S-NSSAI is not associated with the NS-AoS and the UE is move to allowed area for the S-NSSAI based on the partially allowed NSSAI and the NS-AoS. Further, the method includes sending, by the AMF entity, a message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI based on the determination. Further, the method includes receiving a second message indicating that the SMF entity unsubscribes to a UE mobility event notification.

[0018] In an embodiment, the second message is Namf_EventExposure_UnSubscribe service operation message.

[0019] Accordingly, the embodiments herein provide a method for handling a PDU session associated with area restriction for a slice. The method includes receiving, by a SMF entity, an indication from an AMF entity that a PDU session is subjected to area restriction for a S-NSSAI. Further, the method includes subscribing, by the SMF entity, a UE mobility event notification for reporting UE presence in an area of interest by providing the S-NSSAI to the AMF based on the indication.

[0020] In an embodiment, further, the method includes notifying, by the SMF entity, that a UE location is outside or unknown of an area of interest. Further, the method includes performing, by the SMF entity, at least one of: blocking a downlink packet to the UE and disabling a downlink notification to the UE based on the notification.

[0021] In an embodiment, the method includes receiving, by the SMF entity, a PDU session update message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI from the AMF entity. Further, the method includes marking, by the SMF entity, the PDU session as a normal PDU session so as to not apply area restriction for the S-NSSAI. Further, the method includes sending, by the SMF entity, a message indicating that the SMF entity unsubscribes to a UE mobility event notification.

[0022] In an embodiment, the method includes receiving, by the SMF entity, a PDU session update message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI from the AMF entity. Further, the method includes performing one of: keeping the PDU session based on an operator policy and releasing the PDU session based on the operator policy.

[0023] In an embodiment, the SMF entity receives the indication from the AMF entity that the PDU session is subjected to area restriction for the S-NSSAI, when the AMF entity determines that the slice is not uniformly supported in an entire registration area, while the UE initiates the PDU session with the S-NSSAI and a DNN.

[0024] In an embodiment, the SMF entity receives the PDU session update message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI from the AMF entity, when the AMF entity determines at least one of: that the S-NSSAI is moved to an allowed NSSAI from the partially allowed NSSAI and the S-NSSAI is not associated with the NS-AoS.

[0025] In an embodiment, the message is Namf_EventExposure_UnSubscribe service operation message.

[0026] Accordingly, the embodiments herein provide an AMF entity including a restricted area PDU session controller coupled with a processor and a memory. The restricted area PDU session controller is configured to provide at least one of: a S-NSSAI into a partially allowed NSSAI and the S-NSSAI associated with a NS-AoS. Further, the restricted area PDU session controller is configured to determine that the PDU session is subjected to area restriction for the S-NSSAI based on the determination that S-NSSAI is part of at least one of the partially allowed NSSAI and the NS-AoS. Further, the restricted area PDU session controller is configured to send an indication to a SMF entity that the PDU session is subjected to area restriction for the S-NSSAI based on the determination.

[0027] Accordingly, the embodiments herein provide a SMF entity including a restricted area PDU session controller coupled with a processor and a memory. The restricted area PDU session controller is configured to receive an indication from an AMF entity that a PDU session is subjected to area restriction for a S-NSSAI. Further, the restricted area PDU session controller is configured to subscribe to a UE mobility event notification for reporting UE presence in an area of interest by providing the S-NSSAI to the AMF based on the indication.

[0028] According to an embodiment of the disclosure, a wireless communication can be performed efficiently. Especially, a handling PDU session(s) associated with area restriction for slice can be performed efficiently.

[0029] Embodiments herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the following illustration drawings. Embodiments herein are illustrated by way of examples in the accompanying drawings, and in which:

[0030] FIG. 1 depicts a scenario, wherein a SMF entity is not aware of the area restriction for one slice in a wireless communication system, according to existing arts;

[0031] FIG. 2 depicts a scenario where the SMF entity is aware of the area restriction for one slice in the wireless communication system, according to embodiments as disclosed herein;

[0032] FIG. 3 shows various hardware components of an AMF entity, according to embodiments as disclosed herein;

[0033] FIG. 4 shows various hardware components of the SMF entity, according to embodiments as disclosed herein;

[0034] FIG. 5 is a flow chart illustrating a method for handing a PDU session associated with a restricted area for a slice by the AMF entity, according to embodiments as disclosed herein; and

[0035] FIG. 6 is a flow chart illustrating a method for handing the PDU session associated with the restricted area for the slice by the SMF entity, according to embodiments as disclosed herein.

[0036] 3GPP Release 18 introduced a concept of “Partial Network Slice Support” which means the slice is not supported in all the TAs of RA, rather only supported in few TAs of the RA. In this case, the standard has provided the provision for an AMF entity to provide a Partial Allowed NSSAI along with the Allowed NSSAI during registration and a UE configuration update procedure. The Partial Allowed NSSAI will contain the S-NSSAIs with information of TAs where these slices are supported. The UE can directly trigger a PDU session when it moves to a TA where the slice is supported. For the established PDU, if the UE is moved out of the TAs (where slice is Partially supported), then the PDUs shall be deactivated. That is, only a user plane resources shall be deactivated, but PDU sessions will be kept. The UE and the network shall not exchange any uplink and downlink data (both user plane and CP data as part of Non-Access Stratum　(NAS) message), if the UE is out of Partial Allowed NSSAI.

[0037] Similarly, “NS-AoS” (Network Slice Area of Service) has also been introduced. In this case, an operator may configure resources for the Network Slices in cells of TAs where the network slices are to be available, and in areas of the TAs where the network slice is defined to be not available the cells are configured with zero resources. The AMF entity receives, from an Operations, Administration and Maintenance　(OAM) entity, information on availability of a network slice when the granularity is smaller than TA, i.e., if the NS-AoS includes TAs where the network slice is not available in some cells of the TA. During registration and UE configuration update procedure, the AMF entity provides a slice location availability information (NS-AoS) information to the UE. In this case, when the UE moves out of NS-AoS then the existing PDU session is kept but all the resources of the PDU sessions shall be deactivated. The UE and the network shall not exchange any uplink and downlink data (both user plane and CP data as part of NAS message), if the UE is out of NS-AoS.

[0038] The 3GPP has provided a solution for a PDU session associated with area restriction for one slice. In this case, when the AMF entity determines that the slice is associated with Partially Allowed NSSAI or NS-AoS, then the AMF entity provides one indication to a SMF entity that the PDU is subjected to area restriction for that slice. Then, the SMF entity subscribes to the “UE mobility event notification” for reporting UE presence in the Area of Interest by providing S-NSSAI to the AMF entity. When the SMF entity is notified that the UE location is outside of Area of Interest, the SMF entity shall not send user data as payload of NAS message (see clause 5.31.4.1 of the 3GPP) in downlink directions and disable data notification.

[0039] As per TS 23.501 of the 3GPP, if the AMF entity determines that the PDU session is associated with the S-NSSAI present in the Partially Allowed NSSAI, the AMF entity indicates to the SMF entity that the PDU Session is subject to area restrictions for the S-NSSAI. As a result, the SMF entity subscribes to "UE mobility event notification" for reporting UE presence in Area of Interest by providing S-NSSAI to the AMF entity as described in clauses 5.6.11 and 5.3.4.4.

[0040] When the AMF entity determines that the S-NSSAI of a PDU Session is restricted to an NS-AoS in the PDU session, the AMF entity indicates to the SMF entity that the PDU Session is subject to area restriction for the S-NSSAI. As a result, the SMF entity subscribes to "UE mobility event notification" for reporting UE presence in Area of Interest by providing S-NSSAI to the AMF entity as described in clauses 5.6.11 and 5.3.4.4.

[0041] When the SMF entity is notified that the UE location is outside of Area of Interest, the SMF entity shall not send user data as payload of NAS message (see clause 5.31.4.1) in downlink directions and disable data notification.

[0042] But in a scenario when that slice which is moved from the Partially Allowed NSSAI to the Allowed NSSAI (e.g., when UE does Mobility Registration Update), then in the new Registration area, the AMF entity may put that slice to the Allowed NSSAI (which was earlier the Partially Allowed NSSAI) or no more associated with NS-AoS, then the SMF entity is still unaware of this change. Because of this, the SMF entity will continue to treat the existing PDU as subjected to area restriction for that slice because of earlier indication given by the AMF entity. Also, the subscription by the SMF entity to the AMF entity is an unnecessary wastage of resources which will be present in the system.

[0043] FIG. 1 depicts a scenario, wherein the SMF entity (300) is not aware of the area restriction for one slice in a wireless communication system (1000). In step 1, the UE (100) is registered with a network. The AMF entity (200) has provided S-NSSAI1 to the Partially Allowed NSSAI or this S-NSSAI1 is associated with NS-AoS. In step 2, the UE (100) initiates a PDU session with DNN1 and S-NSSAI1. The AMF entity (200) determines that this slice is not uniformly supported in the entire registration area and hence the area restriction applies. So, the AMF entity (200) provides an indication to the SMF entity (300) that this PDU is subjected to area restriction for S-NSSAI1. In step 3, based on this indication, the SMF entity (300) subscribes to the “UE mobility event notification” for reporting UE presence in the Area of Interest by providing S-NSSAI to the AMF entity (200). In step 4, when the SMF entity (300) is notified that the UE location is outside or unknown of the area of interest, the SMF entity (300) blocks the downlink packet and disables the downlink notifications. In step 5, the AMF entity (200) determines that the S-NSSAI1 is moved to the Allowed NSSAI from the Partially Allowed NSSAI or not associated with NS-AoS. In step 6, the SMF entity (300) is still not aware of this update because of which it still considers this PDU where the area restriction for the S-NSSAI1 is still valid and it may continue to block the downlink packet. Also, the subscription which the SMF entity (300) has subscribed to the AMF entity (200) for “UE mobility event notification” for the LADN DNN & S-NSSAI is a wastage of resources and also create undefined behaviour because the AMF entity (200) does not know what to notify as S-NSSAI1 is no more associated with slice area restriction.

[0044] Hence, there is a need in the art for solutions which will overcome the above mentioned drawback(s), among others.

[0045] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0046] The words / phrases "exemplary", “example”, “illustration”, “in an instance”, “and the like”, “and so on”, “etc.”, “etcetera”, “e.g.,”, “i.e.,” are merely used herein to mean "serving as an example, instance, or illustration. Any embodiment or implementation of the present subject matter described herein using the words / phrases "exemplary", “example”, “illustration”, “in an instance”, “and the like”, “and so on”, “etc.”, “etcetera”, “e.g.,” , “i.e.,” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0047] Embodiments herein may be described and illustrated in terms of blocks which carry out a described function or functions.　These blocks, which may be referred to herein as managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by a firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block.　Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

[0048] It should be noted that elements in the drawings are illustrated for the purposes of this description and ease of understanding and may not have necessarily been drawn to scale. For example, the flowcharts / sequence diagrams illustrate the method in terms of the steps required for understanding of aspects of the embodiments as disclosed herein. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Furthermore, in terms of the system, one or more components / modules which comprise the system may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0049] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any modifications, equivalents, and substitutes in addition to those which are particularly set out in the accompanying drawings and the corresponding description. Usage of words such as first, second, third etc., to describe components / elements / steps is for the purposes of this description and should not be construed as sequential ordering / placement / occurrence unless specified otherwise.

[0050] The following abbreviations and definitions have been referred to herein:

[0051] AMF: Access and Mobility Management Function

[0052] SMF: Session Management Function

[0053] UE: User Equipment

[0054] 3GPP: 3rd Generation Partnership Project

[0055] NSSAI : Network Slice Selection Assistance Information

[0056] S-NSSAI: Single - Network Slice Selection Assistance Information

[0057] NS-AoS: Network Slice Area of Service

[0058] TA: Tracking Area

[0059] RA: Registration Area

[0060] The embodiments herein achieve a method for handing a PDU session associated with a restricted area for a slice. The method includes providing, by an AMF entity, at least one of: a S-NSSAI into a partially allowed NSSAI and the S-NSSAI associated with a NS-AoS. Further, the method includes determining, by the AMF entity, the PDU session is subjected to area restriction for the S-NSSAI based on the determination that S-NSSAI is part of at least one of the partially allowed NSSAI and the NS-AoS. Further, the method includes sending, by the AMF entity, an indication to a SMF entity that the PDU session is subjected to area restriction for the S-NSSAI based on the determination.

[0061] The systems and methods can be used for ensuring that the AMF entity, the SMF entity and the UE are correctly handling the existing PDU session associated with area restriction for one slice in 5G systems.

[0062] In an embodiment, when the AMF entity does not indicate to the SMF entity that the PDU session is subject to area restriction for the S-NSSAI, based on a local configuration, the SMF entity may unsubscribe the "UE mobility event notification" event in the AMF if this event has been subscribed before.

[0063] Referring now to the drawings, and more particularly to FIG. 2 to FIG. 6, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0064] When the AMF entity determines that the S-NSSAI1 is moved to the Allowed NSSAI from the Partially Allowed NSSAI or not associated with NS-AoS, then the AMF entity indicates in Nsmf_PDUSession_UpdateSMContext service operation to the SMF entity that this PDU is not subjected to area restriction for S-NSSAI1 anymore. Based on this indication, the SMF entity will consider or mark this PDU as normal PDU session. Also, the SMF entity un-subscribes to the AMF entity to "UE mobility event notification" service. Based on an operator policy, the SMF entity may decide to keep or release the PDU after receiving this indication from the AMF entity.

[0065] The proposed method for the SMF entity to be aware of the slices when these slices are not associated with the partially allowed NSSAI or the NS-AoS so that the SMF entity will treat these slices like any normal PDU session. Also, the subscription towards the AMF entity is no more needed which means the SMF entity shall unsubscribe from the existing event with the AMF entity. This results in avoiding unnecessary signaling between the devices. This results in avoiding the resource wastage (e.g., signaling, power usage, CPU usage or the like).

[0066] FIG. 2 depicts a scenario where the SMF entity (300) is aware of the area restriction of a slice in a wireless communication system (1000). The wireless communication system (1000) can be, for example, but not limited to a fourth generation (4G) network, a 5G network, a sixth generation (6G) network, ORAN or the like. In step 1, a UE (100) is registered with the network. The UE (100) can be, for example, but not limited to a laptop, a desktop computer, a notebook, a Device-to-Device (D2D) device, a vehicle to everything (V2X) device, a smartphone, a foldable phone, a smart TV, a tablet, an immersive device, and an internet of things (IoT) device. The AMF entity has provided S-NSSAI1 into Partially Allowed NSSAI or this S-NSSAI1 is associated with NS-AoS.

[0067] In step 2, the UE (100) initiates a PDU session with DNN1 and S-NSSAI1. The AMF entity (200) determines that this slice is not uniformly supported in the entire registration area and hence the area restriction applies. So, the AMF entity (200) provides indication to the SMF entity (300) that this PDU is subjected to area restriction for S-NSSAI1. In step 3, based on this indication, the SMF entity (300) subscribes to “UE mobility event notification” for reporting the UE presence in the Area of Interest by providing S-NSSAI to the AMF entity (200). In step 4, when the SMF entity (300) is notified that the UE location is outside or unknown of the area of interest, the SMF entity (300) blocks downlink packet(s) and disables downlink notification(s). In step 5, the AMF entity (200) determines that the S-NSSAI1 is moved to the Allowed NSSAI from the Partially Allowed NSSAI or not associated with NS-AoS. In step 6, the AMF entity (200) sends a Nsmf_PDUSession_UpdateSMContext service operation and indicates that this PDU is not subjected to area restriction for S-NSSAI1 anymore. In step 7, based on the received indication from the AMF entity (200), the SMF entity (300) marks this as a normal PDU session and does not apply area restriction for the S-NSSAI1. In step 8, the SMF entity (300) un-subscribes to the AMF entity (200) to "UE mobility event notification" service by sending a Namf_EventExposure_UnSubscribe service operation.

[0068] In an embodiment, when the AMF entity (200) determines that the S-NSSAI1 is moved to the Allowed NSSAI from the Partially Allowed NSSAI or not associated with NS-AoS, then the AMF entity (200) indicates in Nsmf_PDUSession_UpdateSMContext service operation to the SMF entity (300) that this PDU is not subjected to area restriction for S-NSSAI1 anymore.

[0069] In an embodiment, the SMF entity (300) will consider or mark this PDU as a normal PDU session based on the indication received from the AMF entity (200) in a Nsmf_PDUSession_UpdateSMContext service operation.

[0070] The SMF entity (300) may keep this PDU session and un-subscribe to the AMF entity (200) to "UE mobility event notification" service by sending a Namf_EventExposure_UnSubscribe service operation.

[0071] After receiving Nsmf_PDUSession_UpdateSMContext service operation from the AMF entity (200) that this PDU is not subjected area restriction for S-NSSAI1, the SMF entity (300) may decide to keep or release the PDU based on the operator policy.

[0072] In this embodiment, Nsmf_PDUSession_UpdateSMContext service operation is used only for illustration purpose. This can be any message or service operation which the AMF entity (200) uses to indicate the information / indication that the respective PDU session is not subjected to area restriction for S-NSSAI1. Similarly, the indication can be that the respective PDU session subjected to area restriction for the slice is disabled.

[0073] In this embodiment, based on any message or service operation, the AMF entity (200) indicates the information that the respective PDU is not subjected to area restriction for S-NSSAI1, it is illustrated that the SMF entity (300) releases the PDU session, but this can be any network function (NF) in the network. For example, on determining that respective PDU session not subjected to area restriction for S-NSSAI1, the AMF entity (200) can trigger release of the PDU session (for e.g., by setting PDU sessions status IE as INACTIVE and indicating to the UE (100)), making the UE (100) to release the PDU session or requesting the SMF entity (300) to release the PDU session by invoking respective service operation(s)　(e.g., Nsmf_PDUSession_release), which will make the SMF entity (300) to release the PDU session.

[0074] In an embodiment, when the AMF entity (200) determines that the S-NSSAI of the PDU session is restricted to the NS-AoS in the PDU session, the AMF entity (200) indicates to the SMF entity (300) that the PDU session is subject to area restriction for the S-NSSAI. As a result, the SMF entity (300) subscribes to the "UE mobility event notification" event for reporting UE presence in area of interest by providing S-NSSAI to the AMF entity (200) as described in clauses 5.6.11 and 5.3.4.4 if this event has not been subscribed before. The AMF entity (200) determines the UE presence in Area of Interest as described in Annex D, clauses D.1 and D.2 of TS 23.502 and notifies the result to the SMF entity (300). When the SMF entity (200) is notified that the UE location is outside of area of interest, the SMF entity (300) shall not send user data as payload of the NAS message (see clause 5.31.4.1) in the downlink directions and disable the data notification. When the AMF entity (200) does not indicate to the SMF entity (300) that the PDU Session is subject to area restriction for the S-NSSAI, based on the local configuration, the SMF entity (300) may unsubscribe the "UE mobility event notification" event in the AMF entity (200) if this event has been subscribed before.

[0075] If the AMF entity (200) determines that the PDU session is associated with the S-NSSAI present in the partially allowed NSSAI, the AMF entity (200) indicates to the SMF entity (300) that the PDU session is subject to area restrictions for the S-NSSAI. As a result, the SMF entity (300) subscribes to the "UE mobility event notification" event for reporting the UE presence in area of interest by providing S-NSSAI to the AMF entity (200) as described in clauses 5.6.11 and 5.3.4.4 if this event has not been subscribed before. When the AMF entity (200) does not indicate to the SMF entity (300) that the PDU session is subject to area restriction for the S-NSSAI, the SMF entity (300) may unsubscribe "UE mobility event notification" event in the AMF entity (200) and if this event has been subscribed before.

[0076] For the UE (100) or AN initiated modification or the AMF entity (200) initiated modification, the SMF entity (300) responds to the AMF entity (200) through Nsmf_PDUSession_UpdateSMContext Response, or otherwise during PDU session update / modification procedure, if the SMF entity (300) does not receive the indication indicating that the PDU session is subject to area restriction for the S-NSSAI, and if the SMF entity (300) has subscribed the "UE mobility event notification" event in the AMF entity (200) before, the SMF entity (300) may unsubscribe "UE mobility event notification" event in the AMF entity (200).

[0077] FIG. 3 shows various hardware components of the AMF entity (200), according to embodiments as disclosed herein. In an embodiment, the AMF entity (200) includes a processor (210), a communicator (220), a memory (230), and a restricted area PDU session controller (240). The processor (210) is coupled with the communicator (220), the memory (230), and the restricted area PDU session controller (240).

[0078] The restricted area PDU session controller (240) provides at least one of: the S-NSSAI into the partially allowed NSSAI and the S-NSSAI associated with the NS-AoS. Further, the restricted area PDU session controller (240) determines that the PDU session is subjected to area restriction for the S-NSSAI based on the determination that S-NSSAI is part of at least one of the partially allowed NSSAI and the NS-AoS. Further, the restricted area PDU session controller (240) sends an indication to the SMF entity (300) that the PDU session is subjected to area restriction for the S-NSSAI based on the determination.

[0079] Further, the restricted area PDU session controller (240) receives a first message indicating that the SMF entity (300) subscribes to the UE mobility event notification for reporting the UE presence in the area of interest by providing the S-NSSAI to the AMF entity (200).

[0080] In an embodiment, the restricted area PDU session controller (240) determines at least one of: that the S-NSSAI is moved to an allowed NSSAI from the partially allowed NSSAI and the S-NSSAI is not associated with the NS-AoS and the UE (100) is moved to allowed area for the S-NSSAI based on the partially allowed NSSAI and the NS-AoS. Further, the restricted area PDU session controller (240) sends a message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI based on the determination. Further, the restricted area PDU session controller (240) receives a second message indicating that the SMF entity (300) unsubscribes to a UE mobility event notification. The second message is Namf_EventExposure_UnSubscribe service operation message.

[0081] The restricted area PDU session controller (240) is implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by firmware.

[0082] The processor (210) may include one or a plurality of processors. The one or the plurality of processors may be a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor (210) may include multiple cores and is configured to execute the instructions stored in the memory (230).

[0083] Further, the processor (210) is configured to execute instructions stored in the memory (230) and to perform various processes. The communicator (220) is configured for communicating internally between internal hardware components and with external devices via one or more networks. The memory (230) also stores instructions to be executed by the processor (210). The memory (230) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (230) may, in some examples, be considered a non-transitory storage medium. The term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term “non-transitory” should not be interpreted that the memory (230) is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).

[0084] Although FIG. 3 shows various hardware components of the AMF entity (200) but it is to be understood that other embodiments are not limited thereon. In other embodiments, the AMF entity (200) may include less or more number of components. Further, the labels or names of the components are used only for illustrative purposes and does not limit the scope of the invention. One or more components can be combined together to perform the same or substantially similar function in the AMF entity (200).

[0085] FIG. 4 shows various hardware components of the SMF entity (300), according to embodiments as disclosed herein. In an embodiment, the SMF entity (300) includes a processor (310), a communicator (320), a memory (330), and a restricted area PDU session controller (340). The processor (310) is coupled with the communicator (320), the memory (330), and the restricted area PDU session controller (340).

[0086] The restricted area PDU session controller (340) receives the indication from the AMF entity (200) that the PDU session is subjected to area restriction for the S-NSSAI. In an embodiment, the restricted area PDU session controller (340) receives the indication from the AMF entity (200) that the PDU session is subjected to area restriction for the S-NSSAI, when the AMF entity (200) determines that the slice is not uniformly supported in an entire registration area, while the UE (100) initiates the PDU session with the S-NSSAI and a DNN.

[0087] Further, the restricted area PDU session controller (340) subscribes the UE mobility event notification for reporting UE presence in an area of interest by providing the S-NSSAI to the AMF entity (200) based on the indication.

[0088] In an embodiment, further, the restricted area PDU session controller (340) notifies that the UE location is outside or unknown of an area of interest. Further, the restricted area PDU session controller (340) performs at least one of: blocks the downlink packet to the UE (100) and disables the downlink notification to the UE (100) based on the notification.

[0089] In another embodiment, further, the restricted area PDU session controller (340) receives the PDU session update message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI from the AMF entity (200). Further, the restricted area PDU session controller (340) marks the PDU session as the normal PDU session so as to not apply area restriction for the S-NSSAI. Further, the restricted area PDU session controller (340) sends a message indicating that the SMF entity (300) unsubscribes to the UE mobility event notification. The message is the Namf_EventExposure_UnSubscribe service operation message.

[0090] In an embodiment, the restricted area PDU session controller (340) receives the PDU session update message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI from the AMF entity (200), when the AMF entity (200) determines at least one of: that the S-NSSAI is moved to the allowed NSSAI from the partially allowed NSSAI and the S-NSSAI is not associated with the NS-AoS.

[0091] In an embodiment, further, the restricted area PDU session controller (340) receives the PDU session update message to indicate that the PDU session is not subjected to the area restriction for the S-NSSAI from the AMF entity (200). Further, the restricted area PDU session controller (340) performs one of: keeps the PDU session based on an operator policy and releases the PDU session based on the operator policy.

[0092] The restricted area PDU session controller (340) is implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by firmware.

[0093] The processor (310) may include one or a plurality of processors. The one or the plurality of processors may be a general-purpose processor, such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor (310) may include multiple cores and is configured to execute the instructions stored in the memory (330).

[0094] Further, the processor (310) is configured to execute instructions stored in the memory (330) and to perform various processes. The communicator (320) is configured for communicating internally between internal hardware components and with external devices via one or more networks. The memory (330) also stores instructions to be executed by the processor (310). The memory (330) may include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (330) may, in some examples, be considered a non-transitory storage medium. The term “non-transitory” may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term “non-transitory” should not be interpreted that the memory (330) is non-movable. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in Random Access Memory (RAM) or cache).

[0095] Although FIG. 4 shows various hardware components of the SMF entity (300) but it is to be understood that other embodiments are not limited thereon. In other embodiments, the SMF entity (300) may include less or more number of components. Further, the labels or names of the components are used only for illustrative purposes and does not limit the scope of the invention. One or more components can be combined together to perform the same or substantially similar function in the SMF entity (300).

[0096] FIG. 5 is a flow chart (500) illustrating a method for handing the PDU session associated with the restricted area for the slice by the AMF entity (200), according to embodiments as disclosed herein. The operations (502-506) are handled by the restricted area PDU session controller (240).

[0097] At 502, the method includes providing at least one of: the S-NSSAI into the partially allowed NSSAI and the S-NSSAI associated with the NS-AoS. At 504, the method includes determining the PDU session is subjected to area restriction for the S-NSSAI based on the determination that S-NSSAI is part of at least one of the partially allowed NSSAI and the NS-AoS. At 506, the method includes sending an indication to the SMF entity (300) that the PDU session is subjected to area restriction for the S-NSSAI based on the determination.

[0098] FIG. 6 is a flow chart (600) illustrating a method for handing the PDU session associated with the restricted area for the slice by the SMF entity (300), according to embodiments as disclosed herein. The operations (602-604) are handled by the restricted area PDU session controller (340).

[0099] At 602, the method includes receiving the indication from the AMF entity (200) that the PDU session is subjected to area restriction for the S-NSSAI. At 604, the method includes subscribing to the UE mobility event notification for reporting UE presence in the area of interest by providing the S-NSSAI to the AMF entity (200) based on the indication.

[0100] The various actions, acts, blocks, steps, or the like in the flow charts (500 and 600) may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.

[0101] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[0102] The embodiment disclosed herein describes systems and methods for ensuring that the AMF entity (200), the SMF entity (300) and the UE (100) are correctly handling the existing PDU session associated with area restriction for one slice in 5G systems. Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in e.g., Very high speed integrated circuit Hardware Description Language (VHDL) another programming language, or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means which could be e.g., hardware means like e.g., an ASIC, or a combination of hardware and software means, e.g. an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, e.g., using a plurality of CPUs.

[0103] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the embodiments as described herein.

Claims

1.A method performed by an access and mobility management function (AMF) entity in a wireless communication system, the method comprising:identifying a user equipment (UE) is registered with a single-network slice selection assistance information (S-NSSAI) of a partially allowed NSSAI;identifying a protocol data unit (PDU) session associated with the S-NSSAI is present in the partially allowed NSSAI; andin case that the PDU session is present in the partially allowed NSSAI, transmitting, to a session management function (SMF) entity, an indication of the PDU session is subjected to an area restrictions for the S-NSAAI,wherein an UE mobility event notification is subscribed based on the indication.2.The method of claim 1,wherein in case that the indication is not transmitted to the SMF entity, the UE mobility event notification is unsubscribed.3.The method of claim 1, further comprising:based on the UE mobility event notification, receiving, from the SMF entity, the S-NSSAI for reporting an UE presence in an area of interest.4.The method of claim 1, further comprising:identifying the PDU session associated with the S-NSSAI is restricted to an area of service (NS-AoS); andin case that the PDU session is restricted to the NS-AoS, transmitting, to the SMF entity, the indication of the PDU session is subjected to the area restrictions for the S-NSAAI,wherein the UE mobility event notification is subscribed based on the indication.5.A method performed by a session management function (SMF) entity in a wireless communication system, the method comprising:identifying a protocol data unit (PDU) session associated with a single-network slice selection assistance information (S-NSSAI) is present in a partially allowed NSSAI;in case that the PDU session is present in the partially allowed NSSAI, receiving, from an access and mobility management function (AMF) entity, an indication of the PDU session is subjected to an area restrictions for the S-NSAAI, andbased on the indication, subscribing an UE mobility event notification.6.The method of claim 5, further comprising:in case that the indication is not received, unsubscribing the UE mobility event notification.7.The method of claim 5, further comprising:based on the UE mobility event notification, transmitting, to the AMF entity, the S-NSSAI for reporting an UE presence in an area of interest.8.The method of claim 5, further comprising:in case that the PDU session associated with the S-NSSAI is restricted to an area of service (NS-AoS), receiving, from the AMF entity, the indication of the PDU session is subjected to the area restrictions for the S-NSAAI; andbased on the indication, subscribing the UE mobility event notification .9.An access and mobility management function (AMF) entity in a wireless communication system, the AMF entity comprising:a processor;a memory; anda controller coupled with the processor and the memory, the controller configured to:identify a user equipment (UE) is registered with a single-network slice selection assistance information (S-NSSAI) of a partially allowed NSSAI;identify a protocol data unit (PDU) session associated with the S-NSSAI is present in the partially allowed NSSAI; andin case that the PDU session is present in the partially allowed NSSAI, transmit, to a session management function (SMF) entity, an indication of the PDU session is subjected to an area restrictions for the S-NSAAI,wherein an UE mobility event notification is subscribed based on the indication.10.The AMF entity of claim 9,wherein in case that the indication is not transmitted to the SMF entity, the UE mobility event notification is unsubscribed.11.The AMF entity of claim 9, wherein the controller is further configured to:based on the UE mobility event notification, receive, from the SMF entity, the S-NSSAI for reporting an UE presence in an area of interest.12.The AMF entity of claim , AMF entityidentify the PDU session associated with the S-NSSAI is restricted to an area of service (NS-AoS); andin case that the PDU session is restricted to the NS-AoS, transmit, to the SMF entity, the indication of the PDU session is subjected to the area restrictions for the S-NSAAI,wherein the UE mobility event notification is subscribed based on the indication.13.A session management function (SMF) entity in a wireless communication system, the SMF entity comprising:a processor;a memory; anda controller coupled with the processor and the memory, the controller configured to:identify a protocol data unit (PDU) session associated with a single-network slice selection assistance information (S-NSSAI) is present in a partially allowed NSSAI;in case that the PDU session is present in the partially allowed NSSAI, receive, from an access and mobility management function (AMF) entity, an indication of the PDU session is subjected to an area restrictions for the S-NSAAI, andbased on the indication, subscribe an UE mobility event notification event for reporting an UE presence in an area of interest, and transmitting, to the AMF entity, .the S-NSSAI.14.The SMF entity of claim 4, wherein the controller is further configured to:in case that the indication is not received, unsubscribe the UE mobility event notification.15.The SMF entity of claim 13, wherein the controller is further configured to:in case that the PDU session associated with the S-NSSAI is restricted to an area of service (NS-AoS), receive, from the AMF entity, the indication of the PDU session is subjected to area restrictions for the S-NSAAI, andbased on the indication, subscribe the UE mobility event notification.

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