Systems and methods for handling and applying rat restriction policies

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Embodiments herein disclose systems and methods for handling and applying RAT Restriction Policies in wireless communication networks.

Description

SYSTEMS AND METHODS FOR HANDLING AND APPLYING RAT RESTRICTION POLICIES

[0001] Embodiments disclosed herein relate to wireless communication networks, and more particularly to managing Radio Access Technology (RAT) restriction policies in wireless communication networks.

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] The principal object of embodiments herein is to disclose systems and methods for handling and applying RAT Restriction Policies in wireless communication networks.

[0009] Another object of embodiments herein is to disclose methods and systems for enabling the network to trigger deregistration procedures and indicate RAT restriction information as part of the deregistration procedure, if the UE is registered on a PLMN+RAT which is restricted.

[0010] Another object of embodiments herein is to disclose methods and systems for enabling the network to indicate explicitly with a new indication that a currently stored RAT restriction information can be deleted, wherein the UE can then delete the respective RAT restriction information, on receiving the indication.

[0011] Another object of embodiments herein is to disclose methods and systems for enabling the UE to store the RAT restrictions information, on the UE being switched OFF.

[0012] Another object of embodiments herein is to disclose methods and systems for enabling the UE to delete the stored list if the USIM is removed.

[0013] Another object of embodiments herein is to disclose methods and systems for enabling the UE to apply the store RAT restriction information, and select the PLMN+RAT which is not restricted as per the RAT restrictions information, on switch ON.

[0014] Accordingly, the embodiments herein provide a method for handling Access Technology Utilization Control (ATUC) information in a wireless network. The method comprises a network entity determining that an indication has to be provided to a User Equipment (UE) to remove ATUC information; and indicating to the UE to remove the ATUC information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message.

[0015] Accordingly, the embodiments herein provide a method for handling Access Technology Utilization Control (ATUC) information in a wireless network. The method comprises a network entity determining to apply Radio Access Technology (RAT) utilization control to a User Equipment (UE); and triggering a DEREGISTRATION REQUEST message to the UE, wherein the DEREGISTRATION REQUEST message comprises a RAT utilization control IE.

[0016] Accordingly, the embodiments herein provide a method for handling Access Technology Utilization Control (ATUC) information in a wireless network. The method comprises a User Equipment (UE) receiving an indication from a network entity to remove previously stored ATUC information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message, wherein the previously stored ATUC information is associated with a current Public Land Mobile Network (PLMN); and removing the previously stored ATUC information associated with a current Public Land Mobile Network (PLMN).

[0017] Accordingly, the embodiments herein provide a network entity comprising a control module; at least one communication module; and a memory, wherein the control module is coupled with the at least one transceiver module, and the memory. The control module is configured to determine that an indication has to be provided to a User Equipment (UE) to remove ATUC information; and indicate to the UE to remove the ATUC information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message.

[0018] Accordingly, the embodiments herein provide a network entity comprising a control module; at least one communication module; and a memory, wherein the control module is coupled with the at least one transceiver module, and the memory. The control module is configured to determine to apply Radio Access Technology (RAT) utilization control to a User Equipment (UE); and trigger a DEREGISTRATION REQUEST message to the UE, wherein the DEREGISTRATION REQUEST message comprises a RAT utilization control IE (also referred to herein as ATUC control Information Element or ATUC Information Element or Access technology utilization control IE).

[0019] Accordingly, the embodiments herein provide a User Equipment (UE) comprising a control module; at least one communication module; and a memory, wherein the control module is coupled with the at least one transceiver module, and the memory. The control module is configured to receive an indication from a network entity to remove previously stored Access Technology Utilization Control (ATUC) information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message, wherein the previously stored ATUC information is associated with a current Public Land Mobile Network (PLMN); and remove the previously stored ATUC information associated with a current Public Land Mobile Network (PLMN).

[0020] 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 spirit thereof, and the embodiments herein include all such modifications.

[0021] The present disclosure provides a method for managing access policies by explicitly indicating to a User Equipment (UE) that stored RAT restriction information can be deleted, and by triggering a deregistration procedure when a UE's currently used RAT becomes restricted.

[0022] Furthermore, the present disclosure also provides a method to reduce signaling overload and avoid futile registration attempts by the UE. This is achieved by enabling the UE to store RAT restriction information when switched OFF, apply this stored information during network selection upon being switched ON, and delete the stored information if the USIM is removed.

[0023] 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 illustratory drawings. Embodiments herein are illustrated by way of examples in the accompanying drawings, and in which:

[0024] FIG. 1A depicts a scenario, wherein a RAT restriction policy is provisioned to the UE, and now RAT-1 is restricted for the UE, according to existing arts;

[0025] FIG. 1B depicts a scenario, wherein a RAT restriction policy is provisioned to the UE and now one or more RATs are restricted for the UE, and the UE is switched off / on and / or the USIM is removed / inserted back and / or de-registered / registered, according to existing arts;

[0026] FIG. 2 depicts a network, according to embodiments as disclosed herein;

[0027] FIG. 3 depicts scenarios for handling and applying RAT Restriction Policies, according to embodiments as disclosed herein;

[0028] FIG. 4 depicts scenarios for handling and applying RAT Restriction Policies, according to embodiments as disclosed herein;

[0029] FIG. 5 is a flowchart depicting a process for handling ATUC information in the network, according to embodiments as disclosed herein;

[0030] FIG. 6 is a flowchart depicting a process for handling ATUC information in the network, according to embodiments as disclosed herein;

[0031] FIG. 7 is a flowchart depicting a process for handling ATUC information in the network by the UE, according to embodiments as disclosed herein;

[0032] FIG. 8 is a flowchart depicting a process for handling ATUC information in the network by the UE, according to embodiments as disclosed herein;

[0033] FIG. 9 is a flowchart depicting a process for handling ATUC information in the network by the UE, according to embodiments as disclosed herein;

[0034] FIG. 10 is a flowchart depicting a process for handling ATUC information in the network by the UE, according to embodiments as disclosed herein;

[0035] FIG. 11 is a flowchart depicting a process for handling ATUC information in the network by the UE, according to embodiments as disclosed herein;

[0036] FIG. 12 is a flowchart depicting a process for handling ATUC information in the network by the UE, according to embodiments as disclosed herein; and

[0037] FIG. 13 is a flowchart depicting a process for handling ATUC information in the network by the UE, according to embodiments as disclosed herein.

[0038] National roaming services are vital for ensuring seamless connectivity, especially in areas where the primary network operator lacks coverage. Allowing unrestricted use of Radio Access Technologies (RAT) for national roamers can result in technical challenges including interoperability issues, quality of service concerns and network congestion concerns.

[0039] Consider that the UE is registered and using services on RAT-1 / PLMN-1 / AMF-1. A RAT restriction policy is provisioned to the UE and now RAT-1 is restricted for the UE. In this scenario (as depicted in FIG. 1A), if this RAT restriction policy is delivered to the UE, the UE shall send a Re-Registration Request / Service Request / Deregistration request to the AMF including a request for RAT Restriction Information from the Network (if requested by the UDM / AMF) and start the registration procedure on the next acceptable RAT. These procedures increase the signalling load on the network.

[0040] Consider that the UE is registered and using services on RAT-1 / PLMN-1 / AMF-1. A RAT restriction policy is provisioned to the UE and now one or more RATs are restricted for the UE. In this scenario (as depicted in FIG. 1B), when this RAT restriction policy is delivered to the UE, the UE shall send a Registration Request / Re-Registration Request / Service Request / Deregistration request to the AMF including a request for RAT Restriction Information from the Network (if requested by the UDM / AMF) and start the registration procedure on the next acceptable RAT. However, if the UE is switched off / on and / or the USIM is removed / inserted back and / or de-registered / registered, the RAT Restriction Policy is not applied during UE switch off / on and / or USIM removal / insertion and / or de-registration / registration may result in the UE trying on the restricted RAT and getting redirected / rejected. This again increases the signalling load.

[0041] If the UE is currently registered on the PLMN-1+RAT-1 and that very same RAT-1 is restricted for the user, then it is not clear as to how the network communicates this information to the UE. Given this is a restricted RAT, but the UE is already registered, the network will not be in a position to wait for the UE to initiate MO service request and provide a reject to the UE. At the same time, the UEs MT traffic also will be blocked, but the UE may not be aware of this. Similarly, if the particular PLMN-1+RAT-1 (which was indicated as restricted earlier) is now allowed for the UE, it is not clear as to the network communicates this information to the UE.

[0042] Hence, there is a need in the art for solutions which will overcome the above mentioned drawback(s), among others.

[0043] 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.

[0044] For the purposes of interpreting this specification, the definitions (as defined herein) will apply and whenever appropriate the terms used in singular will also include the plural and vice versa. It is to be understood that the terminology used herein is for the purposes of describing particular embodiments only and is not intended to be limiting. The terms "comprising", "having" and "including" are to be construed as open-ended terms unless otherwise noted.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The embodiments herein achieve systems and methods for handling and applying RAT Restriction Policies in wireless communication networks. Referring now to the drawings, and more particularly to FIGS. 2 through 13, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0050] Embodiments herein disclose systems and methods for handling and applying RAT Restriction Policies (also referred to herein as access technology utilization control information) in wireless communication networks. Embodiments herein disclose methods and systems for enabling the network to trigger deregistration procedures and indicate RAT restriction information / access technology utilization control information as part of the deregistration procedure, for e.g. if the UE is on a PLMN+RAT which is restricted. Embodiments herein disclose methods and systems for enabling the network to indicate explicitly with a new indication that a currently stored RAT restriction information / access technology utilization control information can be deleted, wherein the UE can then delete the respective RAT restriction information, on receiving the indication. Embodiments herein disclose methods and systems for enabling the UE to store the RAT restrictions information, on the UE being switched OFF. Embodiments herein disclose methods and systems for enabling the UE to delete the stored list if the USIM is removed. Embodiments herein disclose methods and systems for enabling the UE to apply the store RAT restriction information, and select the PLMN+RAT which is not restricted as per the RAT restrictions information, on switch ON.

[0051] The following terms and abbreviations have been referred to herein:

[0052] RAT: Radio access technology defined in 3GPP TS 36.304 and 3GPP TS 38.304, respectively.

[0053] UE: User equipment

[0054] PLMN: Public land mobile network

[0055] TAI: Tracking area ID

[0056] EPS: Evolved Packet Service (LTE)

[0057] IE: Information Element

[0058] AMF: Access and Mobility Management Function

[0059] ePDG: Evolved Packet Data Gateway

[0060] MINT: Minimization of Service Interruption

[0061] PDN: Packet Data Network

[0062] FPLMN: Forbidden PLMN

[0063] RPLMN: Registered PLMN

[0064] 3GPP: 3rd Generation Partnership Project

[0065] MS: Mobile Station

[0066] ME: Mobile Equipment

[0067] SUPI: Subscription Permanent Identifier

[0068] RAT: Radio Access Technology

[0069] UDM: Unified Data Management

[0070] PCF: Policy Control Function

[0071] RAN: Radio Access Network

[0072] HSS: Home Subscriber Server

[0073] The terms RAT-Type and RAT are used interchangeably herein, and have the same meaning and they represent at least one of the following: 5G, 4G, 3G, 2G, EPS, 5GS, NR, NR in unlicensed bands, NR (LEO) satellite access, NR (MEO) satellite access, NR (GEO) satellite access, NR (OTHERSAT) satellite access, NR RedCap, E-UTRA, E-UTRA in unlicensed bands, NB-IoT or NB-S1, WB-IoT, LTE-M, and so on.

[0074] The terms 'RAT restriction policy', 'RAT Restriction Information' and 'access technology utilization control information' are used interchangeably herein and have the same meaning.

[0075] The terms 'RAT' and 'access technology' are used interchangeably herein and have the same meaning.

[0076] Consider that the UE is registered and using services on RAT-1 / PLMN-1 / AMF-1. A RAT restriction policy is provisioned to the UE and now one or more RATs are restricted for the UE. In this scenario, the network (RAT-1 / PLMN-1 / AMF-1) may Hand Over the UE to an acceptable / allowed RAT or trigger deregistration procedure and provide RAT restriction information ("RAT Restriction Information") to the UE or deregister and redirect / HO to alternate acceptable RAT. By doing so, the signalling load can be avoided when the UE triggers a registration procedure again (after receiving the "RAT Restriction Information").

[0077] FIG. 2 depicts a network. The network 200, as depicted, comprises a RAN node (for example, eNB for EPS, NG-RAN for 5GS) 201, an AMF 202, and a HSS / UDM / PCF 203. The AMF 202 can be considered to be an example of a network entity. The AMF 202 can further comprise a control module 202A, at least one communication module 202B, and a memory 202C.

[0078] In the embodiment shown herein, the control module 202A may comprise one or more microprocessors, circuits, and other hardware configured for processing. The control module 202A can be configured to execute instructions stored in the memory 202C.

[0079] The control module 202A can be at least one of a single processor, a plurality of processors, multiple homogeneous or heterogeneous cores, multiple Central Processing Units (CPUs) of different kinds, microcontrollers, special media, and other accelerators. The control module 202A may be an Application Processor (AP), a graphics-only processing unit such as a Graphics Processing Unit (GPU), a Visual Processing Unit (VPU), and / or an Artificial Intelligence (AI)-dedicated processor such as a Neural Processing Unit (NPU).

[0080] In the embodiment shown herein, the at least one communication module 202B is configured to enable communication between the AMF 202 and at least one external entity (such as, but not limited to, the UE 204, the RAN node 201, the UDM / PCF 203, and so on) through a network or cloud. The at least one communication module 202B through which the AMF 202 and the server communicate may be in the form of either a wired network, a wireless network, or a combination thereof. The wired and wireless communication networks may comprise, but are not limited to, Global Positioning System (GPS), Global System for Mobile Communications (GSM), Local Area Network (LAN), Wireless Fidelity (Wi-Fi) compatibility, Bluetooth Low Energy (BLE), Near-field Communication (NFC), and so on. The wireless communication may further comprise one or more of Bluetooth (registered trademark), Zonal Intercommunication Global Standard (ZigBee) (registered trademark), short-range wireless communication such as Ultra-wideband (UWB), medium-range wireless communication such as Wi-Fi (registered trademark), or long-range wireless communication such as Third Generation (3G), Fourth Generation (4G), or Worldwide Interoperability for Microwave Access (WiMAX) (registered trademark), according to the usage environment.

[0081] In the embodiment shown herein, the memory 202C may comprise one or more volatile and non-volatile memory components that are capable of storing data and instructions to be executed. Examples of the memory module 202C can be, but are not limited to, NAND, embedded Multimedia Card (eMMC), Secure Digital (SD) cards, Universal Serial Bus (USB), Serial Advanced Technology Attachment (SATA), Solid-State Drive (SSD), and so on. The memory 202C may also include one or more computer-readable storage media. Examples of non-volatile storage elements may include magnetic hard disks, optical discs, floppy discs, flash memories, or forms of Electrically Programmable Memories (EPROM) or Electrically Erasable and Programmable Memories (EEPROM). In addition, the memory 202C 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 to mean that the memory 202C 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).

[0082] The control module 202A can handle Access Technology Utilization Control (ATUC) information in the network 200. The control module 202A can determine that an indication has to be provided to the UE 204 to remove ATUC information. On determining that the indication has to be provided to the UE 204 to remove ATUC information, the control module 202A can indicate to the UE 204 to remove the ATUC information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message. In an embodiment herein, the control module 202A can indicate to the UE 204 to remove the ATUC information by setting a length of an ATUC contents field in the ATUC control IE to zero.

[0083] The control module 202A can determine to apply RAT / access technology utilization control information to the UE 204. The control module 202A triggers a DEREGISTRATION REQUEST message to the UE 204, wherein the DEREGISTRATION REQUEST message comprises a RAT / access technology utilization control IE. The control module 202A can set a 5GMM cause value in the DEREGISTRATION REQUEST message to #15 "No suitable cells in tracking area". The control module 202A can trigger a DEREGISTRATION REQUEST message towards the UE 204, for example, when the UE 204 is restricted for the current registered RAT.

[0084] The network 200 can be connected to at least one UE 204. The UE 204 can further comprise a control module 204A, at least one communication module 204B, and a memory 204C.

[0085] In the embodiment shown herein, the control module 204A may comprise one or more microprocessors, circuits, and other hardware configured for processing. The control module 204A can be configured to execute instructions stored in the memory 204C.

[0086] The control module 204A can be at least one of a single processor, a plurality of processors, multiple homogeneous or heterogeneous cores, multiple Central Processing Units (CPUs) of different kinds, microcontrollers, special media, and other accelerators. The control module 204A may be an Application Processor (AP), a graphics-only processing unit such as a Graphics Processing Unit (GPU), a Visual Processing Unit (VPU), and / or an Artificial Intelligence (AI)-dedicated processor such as a Neural Processing Unit (NPU).

[0087] In the embodiment shown herein, the at least one communication module 204B is configured to enable communication between the UE 204 and at least one external entity (such as, but not limited to, the RAN node 201, the AMF 202, the UDM / PCF 203, and so on) through a network or cloud. The at least one communication module 204B through which the UE 204 and the server communicate may be in the form of either a wired network, a wireless network, or a combination thereof. The wired and wireless communication networks may comprise, but are not limited to, Global Positioning System (GPS), Global System for Mobile Communications (GSM), Local Area Network (LAN), Wireless Fidelity (Wi-Fi) compatibility, Bluetooth Low Energy (BLE), Near-field Communication (NFC), and so on. The wireless communication may further comprise one or more of Bluetooth (registered trademark), Zonal Intercommunication Global Standard (ZigBee) (registered trademark), short-range wireless communication such as Ultra-wideband (UWB), medium-range wireless communication such as Wi-Fi (registered trademark), or long-range wireless communication such as Third Generation (3G), Fourth Generation (4G), or Worldwide Interoperability for Microwave Access (WiMAX) (registered trademark), according to the usage environment.

[0088] In the embodiment shown herein, the memory 204C may comprise one or more volatile and non-volatile memory components that are capable of storing data and instructions to be executed. Examples of the memory 204C can be, but are not limited to, NAND, embedded Multimedia Card (eMMC), Secure Digital (SD) cards, Universal Serial Bus (USB), Serial Advanced Technology Attachment (SATA), Solid-State Drive (SSD), and so on. The memory 204C may also include one or more computer-readable storage media. Examples of non-volatile storage elements may include magnetic hard disks, optical discs, floppy discs, flash memories, or forms of Electrically Programmable Memories (EPROM) or Electrically Erasable and Programmable Memories (EEPROM). In addition, the memory 204C 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 to mean that the memory 204C 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).

[0089] The control module 204A can receive an indication from a network entity (for example, the AMF 202) to remove previously stored ATUC information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message, via the communication module 204B. In an embodiment herein, the previously stored ATUC information can be associated with a current Public Land Mobile Network (PLMN). In an embodiment herein, the PLMN can be a Registered PLMN (RPLMN) or the equivalent PLMN. The control module 204A can then remove the previously stored ATUC information.

[0090] In an embodiment herein, when the ATUC information is deleted, it is specified if the deleted ATUC information is for the current PLMN, RPLMN or the equivalent PLMN.

[0091] In an embodiment herein, the control module 204A can store the ATUC information, on the UE 204 being switched OFF. The control module 204A can further apply the stored ATUC information, on the UE being switched ON by selecting the PLMN using all access technologies that the MS is capable of except for the RATs that are restricted for the PLMN.

[0092] In an embodiment herein, the control module 204A can delete the stored ATUC information, on determining that there is a change in at least one of a Universal Subscriber Identity Module (USIM) in the UE 204. In an embodiment herein, the control module 204A can delete the stored ATUC information, on determining that there is a change in a Subscription Permanent Identifier (SUPI). In an embodiment herein, the control module 204A can delete the stored ATUC information, on determining that there is a mismatch in the SUPI; i.e., the ATUC information is stored along with the SUPI (for example, ATUC-1+SUPI-1) when it is received from the network in a NAS message. Now if the SUPI changes (for example, to SUPI-2), then the ATUC information has to be deleted; i.e., ATUC-1 corresponding to SUPI-1 has to be deleted. In an embodiment herein, the control module 204A can delete the stored ATUC information, on determining that the USIM has been removed from the UE 204.

[0093] As depicted in FIG. 3, in step 301, the UDM / PCF 203 decides to perform UE Parameter Update (UPU) / UE Configuration Update (UCU) / Steering of Roaming (SOR) update to update the UE 204 about RAT Restriction Information. In step 302, the RAT restriction information is received by the AMF 202 from the UDM / PCF 203 or any other core network entity. In step 303, the AMF 202 forwards the received RAT restriction information to the RAN node 201 or the AMF itself can generate the RAT restriction information. In step 304, the RAN node 201 determines that the UE is currently on the RAT which is restricted for the UE based on the RAT restriction information received from the core network. Alternatively, the core network 200 can determine that the UE 204 is currently on the RAT which is restricted for the UE 204 based on the RAT restriction information. The network 200 can perform at least one of steps 305A, or 305B. In step 305A, the RAN node 201 triggers the handover procedure (which can be one of a Xn based handover procedure, a S1 based handover procedure, an inter cell handover procedure, an inter-system handover procedure, and so on) or a redirection procedure (as described in TS 23.501 or TS 23.401) and initiates to handover / redirect the UE 204 to a target RAT or cell (which is acceptable and not restricted based on the RAT restriction information of the UE 204). In step 305B, alternatively, the core network 200 can determine that the UE 204 is currently on the RAT which is restricted for the UE 204 based on the RAT restriction information. In an embodiment herein, the network 200 can instruct the RAN node 201 to trigger Handover procedure / redirect. In an embodiment herein, the network 200 can trigger Handover procedure / redirection procedure to move the UE to the target RAT which is acceptable; i.e., not restricted for the UE 204. In an example scenario, the UE 204 can Hand Over to an acceptable RAT (say RAT-2, for example, eNB, according to TS 23.502, 4.9 Handover procedures).

[0094] Redirection procedure:

[0095] For connected mode mobility from 5GS to EPS, either inter-system handover or RRC Connection Release with Redirection to E-UTRAN is performed. At inter-system handover, the AMF 202 selects a target MME (not shown), based on 2 octet TAC format used in the Target ID (as specified in TS 38.413). During the TAU or Attach procedure, a HSS+UDM 203 cancels any AMF registration associated with the 3GPP access, but does not cancel an AMF registration associated with the non-3GPP access. Further, an AMF that was serving the UE over both 3GPP and non-3GPP accesses will not consider the UE 204 as deregistered over non 3GPP access.

[0096] For connected mode mobility from EPC to 5GC, either inter-system handover or RRC Connection Release with Redirection to NG-RAN is performed. At inter-system handover, the MME selects a target AMF based on Type Allocation Code (TAC)　used in the Target ID as specified in TS 38.413. During the Registration procedure, the HSS+UDM 203 cancels any MME registration.

[0097] When the UE 204 supports single-registration mode or dual-registration mode without N26 interface:

[0098] - If the UE 204 is in CM-CONNECTED state in 5GC, the NG-RAN may perform RRC Connection Release with Redirection to E-UTRAN based on certain criteria (for example, based on local configuration in NG-RAN, or triggered by the AMF 202, on receiving a Handover Request message from NG-RAN).

[0099] - If the UE 204 is in ECM-CONNECTED state in EPC, the E-UTRAN may perform RRC Connection release with redirection to NG-RAN based on certain criteria (for example, based on local configuration in E-UTRAN, or triggered by the MME, on receiving a handover request from E-UTRAN).

[0100] Once the target cells are determined, the NG-RAN initiates RRC redirection procedure towards the target cells, or the NG-RAN initiates handover for the UE with active PDU Sessions associated with the S-NSSAIs which are in the Target NSSAI, if possible.

[0101] When determining whether to redirect the UE, the AMF / MME considers the UE support of S1 / N1 mode, respectively, and the UE's Preferred Network Behaviour and the Supported Network Behaviour of the network the UE is being redirected towards.

[0102] The eNB / gNB may provide a cell reselection priority for each frequency, by means of separate lists for each RAT (including E-UTRA / NR) in the RRC CONNECTION RELEASE message.

[0103] Some of the IEs in the RRC CONNECTION RELEASE message are as follows:

[0104] ReleaseCause: The IE releaseCause can be used to indicate the reason for releasing the RRC Connection (for example, loadBalancingTAUrequired, cs-FallbackHighPriority, or other). A new cause (such as, but not limited to, RAT Restriction) can also be added here.

[0105] RedirectedCarrierInfo: The redirectedCarrierInfo indicates a carrier frequency which is used to redirect the UE to an E-UTRA or NR or an inter-RAT carrier frequency.

[0106] IdleModeMobilityControlInfo: This IE provides dedicated cell reselection priorities.

[0107] Consider that the UE is registered and using services on RAT-1 / PLMN-1, and a RAT restriction policy is provisioned to the UE and now one or more RATs are restricted for the UE. In this scenario (as depicted in FIG. 4), when this RAT restriction policy is delivered to the UE 204, the UE 204 shall send a Registration Request / Service Request / Deregistration request to the AMF 202, wherein the Registration Request / Service Request / Deregistration request optionally includes a request for RAT Restriction Information from the Network 200 (if requested by the UDM / AMF). The UE 204 further starts the registration procedure on the next acceptable RAT. In addition, the UE 204 shall save / memorize the RAT restriction policies ("RAT Restriction Information") in the ME / MS / UE. When the UE 204 (re)initiates Registration / Attach procedure and / or switch On and / or USIM removal / insertion, the UE 204 applies the saved policy ("RAT Restriction Information") and carries out PLMN selection per the allowable RATs; i.e., with the RATs or access technologies on which the RATs are not restricted and ignore / not select the RATs which are restricted; i.e., those are not the candidates for selection. For PLMN selection as described in TS 23.122, the UE performs the PLMN selection in the following order. The MS selects and attempts registration on any PLMN / access technology combinations, if available and allowable, in the following order:

[0108] - either the RPLMN also called as the Last registered PLMN;

[0109] - either the HPLMN (if the EHPLMN list is not present or is empty) or the highest priority EHPLMN that is available (if the EHPLMN list is present);

[0110] - each PLMN / access technology combination in the "User Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order);

[0111] - each PLMN / access technology combination in the "Operator Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order) or stored in the ME (in priority order);

[0112] - other PLMN / access technology combinations with received high quality signal in random order; and

[0113] - other PLMN / access technology combinations in order of decreasing signal quality.

[0114] If no policy ("RAT Restriction Information") is saved, then all the RATs are enabled, i.e., the UE 204 may not apply any RAT Restrictions. This helps in avoiding futile / unnecessary registration attempts on non-allowable RATs and thus reduces signaling overload.

[0115] Additionally, the UE 204 can decide to store the "RAT Restriction Information" for a pre-defined and / or implementation dependent time. The UE 204 can start a timer 'tRR' after receiving "RAT Restriction Information" or for a predefined (x) number of days / time / minutes / seconds.

[0116] Additionally, the UE 204 can delete "RAT Restriction Information" on meeting certain conditions like:

[0117] - SUPI change; and

[0118] - 'tRR' has expired and / or new "RAT Restriction Information" received (with NULL content; i.e., if RAT X was restricted, the network (NW) wants to add it back by sending NULL content).

[0119] In step 401, the UDM 203 decides to perform UE Parameter Update (UPU) / UE Configuration Update (UCU) / SOR update to update the UE 204 about RAT Restriction Information. In step 402, the UDM 203 notifies the changes of the RAT Restriction Information related to the UE to the affected AMF 202 by the means of invoking a Nudm_SDM_Notification service operation. In an embodiment herein, the Nudm_SDM_Notification service operation contains the UDM Update Data that needs to be delivered transparently to the UE 204 over NAS within the Access and Mobility Subscription data. In an embodiment herein, the UDM 203 delivers the RAT Restriction Information to the AMF 202 during the registration procedure. In an embodiment herein, the UDM / UDR or any other NF in the network can deliver the RAT Restriction Information to the AMF 202, using at least one service operation.

[0120] In step 403, if the AMF 202 determines that the UE 204 is not reachable, then the AMF 202 invokes the Nudm_SDM_Info service operation to the UDM 203, indicating that the transmission of UE Parameters Update data is not successful. The UDM 203 considers the procedure as UE Parameters Update procedure as pending and subsequent steps 404-407 are skipped.

[0121] In step 404, the AMF 202 sends a DL NAS Message (for example, Registration Accept, DL NAS TRANSPORT, and so on) containing UPU container / UCU Container / SOR Container with RAT Restriction Information IE, and a message to the served UE. The AMF 202 includes the transparent container received from the UDM, in the DL NAS message.

[0122] In step 405, if the UE 204 has verified that the UDM Update Data is provided by HPLMN, SNPN, or CH and the UDM 203 has requested the UE 204 to send an ack to the UDM 203, the UE 204 sends an UL NAS TRANSPORT message to the serving AMF 202 with a transparent container, including the UE acknowledgement.

[0123] In step 406, if the AMF 202 receives an UL NAS TRANSPORT message with a transparent container carrying a UE acknowledgement from the UE 204, the AMF 202 sends a Nudm_SDM_Info request message including the transparent container to the UDM 203.

[0124] In step 407, if the UDM / AMF 203 / 202 has requested the UE 204 to re-register, the UE 204 waits until it goes back to RRC_IDLE and initiates a Registration procedure (as defined in TS　24.501).

[0125] Additionally, the UE 204 can decide to store the "RAT Restriction Information" for a pre-defined and / or implementation dependent time. The UE 204 can start a timer 'tRR' after receiving "RAT Restriction Information" or for a predefined (Tx) number of days / time / minutes / seconds.

[0126] Additionally, the UE 204 can delete "RAT Restriction Information" on meeting certain conditions like:

[0127] - SUPI change.

[0128] - 'tRR' has expired and / or new "RAT Restriction Information" received (with NULL content; i.e., if RAT X was restricted, the network (NW) wants to add it back by sending NULL content).

[0129] If the UE receives new "RAT Restriction Information" (either a new restriction or with NULL content; i.e., if RAT X was restricted, the NW wants to add it back by sending NULL content; e.g., by setting the length of the IE as zero) optionally while timer "tRR" is running, the UE shall behave as follows:

[0130] - If "RAT Restriction Information" is new / updated, the UE 204 shall stop the currently running timer "tRR" and update the value to the newly received value and start the timer again. If the timer value is not included by the NW, the UE implementation specific value is used, or the UE 204 considers the RAT restriction information to be valid without any time restrictions.

[0131] - If new "RAT Restriction Information" is NULL (i.e., length of the IE is set to zero or no entries of RAT restriction information is provided to the UE 204), the UE 204 shall stop timer "tRR" (if running) since no RAT Restriction policy is currently active, and shall delete the currently stored RAT restriction information.

[0132] The network 200 can send an explicit indication with a value in the information element or send the RAT restriction information IE with size set to zero to indicate to the UE 204 that the stored RAT restriction information(if any) should be deleted by the UE 204.

[0133] In an embodiment herein, if the UE 204 enters the DEREGISTERED state, the UE 204 shall delete the stored RAT restriction information.

[0134] In an embodiment herein, if the UE 204 is switched off, the UE 204 shall delete the stored RAT restriction information.

[0135] In an embodiment herein, if the UE 204 is switched ON and the RAT restriction information is deleted or not available, then the UE 204 shall re-enable all the RATs supported by the UE 204, and shall not disable any RAT(s).

[0136] In an embodiment herein, if the RAT restriction information is deleted or not available, then the UE 204 shall re-enable all the RATs supported by the UE 204, and shall not disable any RAT(s).

[0137] In an embodiment herein, if the UE 204 is switched ON and the RAT restriction information is available / stored, then the UE 204 shall disable the RAT(s) that are restricted based on the RAT restriction information, and shall perform PLMN selection procedure.

[0138] In an embodiment herein, the timer "tRR" is stopped when the UE 204 is switched off or the UE 204 enters a Deregistered state.

[0139] In an embodiment herein, if the UE 204 is switched off when the timer "tRR" is running, the UE 204 shall behave as follows (when the UE is switched on and the USIM in the UE remains the same):

[0140] - let t1 be the time remaining for "tRR" timeout at switch off and let t be the time elapsed between switch off and switch on. If t1 is greater than t, then the timer shall be restarted with the value t1　-　t. If t1 is equal to or less than t, then the timer need not be restarted, and optionally it can be considered as expired. If the UE 204 is not capable of determining t, then the UE 204 shall restart the timer with the value t1, or it can consider the timer has expired.

[0141] In an embodiment herein, the UE deletes the access technology.

[0142] Before the policy is exchanged between the UE 204 and the network 200, the UE 204 should have indicated the support for RAT restriction in the UE capability exchange.

[0143] The terms 'area', 'location', and 'geographical area' as referred to herein may refer to any of cell / cell ID, TAC / TAI, PLMN, MCC / MNC, Latitude / longitude, CAG cell or any geographical location / coordinates.

[0144] If the network did not include a timer value for the RAT restriction, then the UE may choose a time duration for 'tRR' for which the policy will be in effect. It is up to UE implementation on what duration to

[0145] choose for 'tRR'.

[0146] In an embodiment herein, disabling a particular RAT implies that the UE 204:

[0147] a) Can deactivate / disable the access stratum of a particular RAT; or

[0148] b) Will not deactivate the access stratus(or startum) of a particular RAT, but the UE 204 will not select / reselect to that RAT; i.e., will not use this RAT; in other words, the restricted RATs or the PLMNs are not candidates for cell / PLMN selection or cell / PLMN reselection, but optionally, the UE 204 still continues to scan frequencies / search cells of the respective RAT to see if any allowed area / TAI will be available for the UE 204, based on RAT restriction information.

[0149] The RAT restriction information / policy (as depicted in table 1) can be delivered to the UE in such a way that at least one of the below in any order / combination can be used to determine if a given RAT is allowed or forbidden to the UE:

[0150] - Per PLMN-ID: RAT can be restricted on a per PLMN basis; for example, PLMN-1: Allowed: RAT-1,2, Forbidden RAT-3,4.

[0151] - Per TAI: RAT is restricted for a given TAI / RA or for a list of TAI / RA; for example, TAI-1: Allowed: RAT-1,2, Forbidden RAT-3,4.

[0152] - Per cell: RAT can be restricted per PCI / ARFCN or per Global cell ID or for a list of cells; for example, Cell-ID-1: Allowed: RAT-1,2, Forbidden RAT-3,4

[0153] - Per area: Allowed area for a given RAT or forbidden Area for a given RAT.

[0154] - Per time: Example: LTE RAT optionally on PLMN X is forbidden from 9 AM to 6 PM, or NR is forbidden on a list of TAIs for the next two hours, or the time may start when a message or indication is received from the network till the duration expires

[0155] - Per RAT type: This indicates the information on whether a given RAT is allowed or forbidden for the UE.

[0156]

[0157] If the RAT restriction policy is received from the AMF 202, by means of signalling (such as, but not limited to, UCU, Attach / Registration / TAU accept or reject or Detach / Deregistration request), then the UE 204 can apply the policy to that PLMN only (also referred to herein as current PLMN).

[0158] If the RAT restriction policy is delivered by

[0159] HSS / UDM by procedures (such as, but not limited to, SOR / UPU), then the HPLMN can also update the policy for other PLMNs.

[0160] FIG. 5 is a flowchart depicting a process for handling ATUC information in the network. In step 501, the AMF 202 determines that an indication has to be provided to the UE 204 to remove ATUC information. On determining that the indication has to be provided to the UE 204 to remove ATUC information, in step 502, the AMF 202 indicates to the UE 204 to remove the ATUC information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message. In an embodiment herein, the AMF 202 indicates to the UE 204 to remove the ATUC information by setting a length of an ATUC contents field in the ATUC control IE to zero. The various actions in method 500 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 5 may be omitted.

[0161] FIG. 6 is a flowchart depicting a process for handling ATUC information in the network. In step 601, the AMF 202 determines to apply RAT utilization control to the UE 204. In step 602, the AMF 202 triggers a DEREGISTRATION REQUEST message to the UE 204. The DEREGISTRATION REQUEST message comprises a RAT utilization control IE. In an embodiment herein, the AMF 202 sets a 5GMM cause value in the DEREGISTRATION REQUEST message to #15 "No suitable cells in tracking area". In an embodiment herein, the AMF 202 triggers a DEREGISTRATION REQUEST message to the UE 204, when the UE 204 is restricted for the current registered RAT. The various actions in method 600 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 6 may be omitted.

[0162] FIG. 7 is a flowchart depicting a process for handling ATUC information in the network by the UE. In step 701, the UE 204 receives an indication from a network entity (for example, the AMF 202) to remove previously stored ATUC information using an ATUC control Information Element (IE) in a CONFIGURATION UPDATE COMMAND message. In an embodiment herein, the previously stored ATUC information can be associated with a current Public Land Mobile Network (PLMN). In an embodiment herein, the PLMN can be a Registered PLMN (RPLMN). In step 702, the UE 204 removes the previously stored ATUC information. The various actions in method 700 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 7 may be omitted.

[0163] FIG. 8 is a flowchart depicting a process for handling ATUC information in the network by the UE. In step 801, the UE 204 determines that it is being switched OFF, either manually, or in certain scenarios (such as, but not limited to, battery SOC being zero, and so on). On determining that the UE 204 is being switched OFF, in step 802, the UE 204 stores the ATUC information. The various actions in method 800 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 8 may be omitted.

[0164] FIG. 9 is a flowchart depicting a process for handling ATUC information in the network by the UE. In step 901, the UE 204 detects that it has been switched ON, either manually, or automatically (such as, but not limited to, battery being sufficiently charged, and so on). In step 902, the UE 204 applies the stored ATUC information by selecting the PLMN using all access technologies that the MS is capable of except for the RATs that are restricted for the PLMN based on the stored ATUC information. The various actions in method 900 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 9 may be omitted.

[0165] FIG. 10 is a flowchart depicting a process for handling ATUC information in the network by the UE. In step 1001, the UE 204 determines that there is a change in at least one of a USIM in the UE 204. If there is a change in at least one of a USIM in the UE 204 (i.e., when the USIM is removed and a new USIM is inserted in the UE 204), in step 1002, the UE 204 deletes the stored ATUC information.. The various actions in method 1000 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 10 may be omitted.

[0166] FIG. 11 is a flowchart depicting a process for handling ATUC information in the network by the UE. In step 1101, the UE 204 determines that there is a change in the SUPI. If there is a change in the SUPI, in step 1102, the UE 204 deletes the stored ATUC information. The various actions in method 1100 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 11 may be omitted.

[0167] FIG. 12 is a flowchart depicting a process for handling ATUC information in the network by the UE. In step 1201, the UE 204 determines that there is a mismatch in the SUPI. If there is a mismatch in the SUPI, in step 1202, the UE 204 deletes the stored ATUC information. The various actions in method 1200 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 12 may be omitted.

[0168] FIG. 13 is a flowchart depicting a process for handling ATUC information in the network by the UE. In step 1301, the UE 204 determines that the USIM has been removed from the UE 204. On the USIM being removed from the UE 204, in step 1302, the UE 204 deletes the stored ATUC information. The various actions in method 1300 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 13 may be omitted. In yet another embodiment herein, if the USIM is removed and the same USIM is re-inserted, then the UE does not delete the ATUC information.

[0169] 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 elements include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[0170] The embodiments disclosed herein describe systems and methods for handling and applying RAT Restriction Policies in wireless communication networks. 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.

[0171] 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 and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practised with modification within the scope of the embodiments as described herein.

Claims

1.A method performed by a user equipment (UE) in a wireless communication system, the method comprising:transmitting, to an access and mobility management function (AMF) entity, capability information indicating that the UE supports a radio access technology (RAT) control;receiving, from the AMF entity, a first message including an information element for the RAT control, wherein the information element includes a content field set to zero, in case that the capability information indicates that the UE supports the RAT control and information associated with the RAT control stored in the UE needs to be removed; andremoving the information associated with the RAT control stored in the UE, based on the first message.2.The method of claim 1, further comprising:receiving, from the AMF entity, a second message associated with a deregistration procedure including information indicating that a RAT for the UE is restricted, in case that the RAT for the UE is restricted based on a policy.3.The method of claim 1, wherein the information associated with the RAT control stored in the UE is maintained in case that the UE is switched off.4.The method of claim 3, further comprising:in response to the UE being switched on, performing a public land mobile network (PLMN) selection procedure based on the maintained information.5.The method of claim 1, wherein the information associated with the RAT control stored in the UE is deleted in case that a subscription permanent identifier (SUPI) of the UE is changed.6.A method performed by an access and mobility management function (AMF) entity in a wireless communication system, the method comprising:receiving, from a user equipment (UE), capability information indicating that the UE supports a radio access technology (RAT) control;determining a need to remove information associated with the RAT control stored in the UE; andtransmitting, to the UE, a first message including an information element for the RAT control, wherein the information element includes a content field set to zero, in case that the capability information indicates that the UE supports the RAT control and the information associated with the RAT control stored in the UE needs to be removed.7.The method of claim 6, further comprising:determining that a RAT for the UE is restricted based on a policy; andtransmitting, to the UE, a second message associated with a deregistration procedure including information indicating that the RAT for the UE is restricted based on the determination that the RAT for the UE is restricted.8.A user equipment (UE) in a wireless communication system, the UE comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andmemory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the UE to:transmit, to an access and mobility management function (AMF) entity, capability information indicating that the UE supports a radio access technology (RAT) control;receive, from the AMF entity, a first message including an information element for the RAT control, wherein the information element includes a content field set to zero, in case that the capability information indicates that the UE supports the RAT control and information associated with the RAT control stored in the UE needs to be removed; andremove the information associated with the RAT control stored in the UE, based on the first message.9.The UE of claim 8, wherein the instructions further cause the UE to:receive, from the AMF entity, a second message associated with a deregistration procedure including information indicating that a RAT for the UE is restricted, in case that the RAT for the UE is restricted based on a policy.10.The UE of claim 8, wherein the information associated with the RAT control stored in the UE is maintained in case that the UE is switched off.11.The UE of claim 10, wherein the instructions further cause the UE to:in response to the UE being switched on, performing a public land mobile network (PLMN) selection procedure based on the maintained information.12.The UE of claim 8, wherein the information associated with the RAT control stored in the UE is deleted in case that a subscription permanent identifier (SUPI) of the UE is changed.13.An access and mobility management function (AMF) entity in a wireless communication system, the AMF entity comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andmemory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the AMF entity to:receive, from a user equipment (UE), capability information indicating that the UE supports a radio access technology (RAT) control;determine a need to remove information associated with the RAT control stored in the UE; andtransmit, to the UE, a first message including an information element for the RAT control, wherein the information element includes a content field set to zero, in case that the capability information indicates that the UE supports the RAT control and the information associated with the RAT control stored in the UE needs to be removed.14.The AMF entity of claim 13, wherein the instructions further cause the AMF entity to:determine that a RAT for the UE is restricted based on a policy; andtransmit, to the UE, a second message associated with a deregistration procedure including information indicating that the RAT for the UE is restricted based on the determination that the RAT for the UE is restricted.

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