Method and apparatus for handling access technology (AT) restrictions in a wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present disclosure describes techniques for handling AT restrictions is disclosed. In an embodiment, a method implemented at a UE comprises receiving, from a network entity, an access technology utilization control IE (Information Element) via a Non-Access Stratum (NAS) signalling, wherein the access technology utilization control IE comprises access technology utilization control information for a current public land mobile network (PLMN) and at least one equivalent PLMN.

Description

METHOD AND APPARATUS FOR HANDLING ACCESS TECHNOLOGY (AT) RESTRICTIONS IN A WIRELESS COMMUNICATION SYSTEM

[0001] The present disclosure relates to wireless communication. Particularly, but not exclusively, the present disclosure relates to handling Access Technology (AT) restrictions in a wireless communication network.

[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 foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

[0009] In one non-limiting embodiment of the present disclosure, a method of handling Access Technology (AT) restrictions being implemented at a User Equipment (UE) is disclosed. The method comprises receiving, from a network node, a Non-Access Stratum (NAS) message comprising an AT utilization control Information Element (IE). In an exemplary aspect, the AT utilization control IE comprises AT utilization control information of at least one of: plurality of ATs restricted and allowed on a current Public Land Mobile Network (PLMN) and one or more equivalent PLMNs corresponding to the current PLMN. In another exemplary aspect, the UE is registered on the current PLMN. The method further comprises determining a candidate cell for one of: cell selection and cell reselection based on the AT utilization control information.

[0010] In one non-limiting embodiment of the present disclosure, a method of handling Access Technology (AT) restrictions being implemented at a network node is disclosed. The method comprises generating, AT utilization control information for a User Equipment (UE). In an exemplary aspect, the AT utilization control information comprises information of at least one of: a plurality of ATs restricted and allowed on a current PLMN and one or more equivalent PLMNs associated with the UE. The method further comprises transmitting the AT utilization control information to the UE in the AT utilization Information Element (IE) of a Non-Access Stratum (NAS) message for performing one of: cell selection and cell reselection.

[0011] In one non-limiting embodiment of the present disclosure, a User Equipment (UE) for handling Access Technology (AT) restrictions is disclosed. The UE comprises a memory and a processor communicatively connected to the memory. The processor is configured to receive, from a network node, a Non-Access Stratum (NAS) message comprising an AT utilization control Information Element (IE). In an exemplary aspect, the AT utilization control IE comprises AT utilization control information of at least one of: plurality of ATs restricted and allowed on a current Public Land Mobile Network (PLMN) and one or more equivalent PLMNs corresponding to the current PLMN. In another exemplary aspect, the UE is registered on the current PLMN. The processor is configured to determine a candidate cell for one of: cell selection and cell reselection based on the AT utilization control information. The processor is further configured to determine a candidate cell for one of: cell selection and cell reselection based on the AT utilization control information.

[0012] In one non-limiting embodiment of the present disclosure, a network node for handling Access Technology (AT) restrictions is disclosed. The network node comprises a memory and a processor communicatively connected to the memory. The processor is configured to generate AT utilization control information for a User Equipment (UE). In an exemplary aspect, the AT utilization control information comprises information of at least one of: a plurality of ATs restricted and allowed on a current PLMN and one or more equivalent PLMNs associated with the UE. The processor is further configured to transmit the AT utilization control information to the UE in the AT utilization Information Element (IE) of a Non-Access Stratum (NAS) message for performing one of: cell selection and cell reselection.

[0013] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. The same numbers are used throughout the figures to reference like features and components. Some embodiments of at least one of device and methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figures, in which:

[0014] Figure 1A depicts an exemplary environment 100A for transmission of AT utilization control information as per existing systems,

[0015] Figure 1B depicts an exemplary environment 100B in which the techniques of the present disclosure may be implemented,

[0016] Figure 2 depicts a block diagram 200 of a network node for generating AT utilization control information, in accordance with an embodiment of the present disclosure,

[0017] Figure 3 depicts a block diagram 300 of a User Equipment (UE) for handling AT utilization control information, in accordance with an embodiment of the present disclosure,

[0018] Figure 4 depicts a logic flow diagram 400 for generation of AT utilization control information at a network node, in accordance with an embodiment of the present disclosure,

[0019] Figure 5 depicts a logic flow diagram 500 for handling AT utilization control information at a User Equipment, in accordance with an embodiment of the present disclosure,

[0020] Figure 6 depicts, by way of a flowchart, an exemplary method 600 of handling AT restrictions, implemented at a network node, in accordance with an embodiment of the present disclosure,

[0021] Figure 7 depicts, by way of a flowchart, an exemplary method 700 of handling AT restrictions, implement at a User Equipment, in accordance with an embodiment of the present disclosure,

[0022] Figure 8 illustrates a block diagram of an exemplary computer system 1200 for implementing embodiments consistent with the present disclosure,

[0023] Figure 9 illustrates a method 900 performed by a user equipment (UE) according to various embodiments of the present disclosure;

[0024] Figure 10 illustrates a method 1000 performed by a network entity according to various embodiments of the present disclosure.

[0025] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0026] In describing the embodiments, descriptions related to technical contents well-known in the art and not associated directly with the disclosure will be omitted. Such an omission of unnecessary descriptions is intended to prevent obscuring of the main idea of the disclosure and more clearly transfer the main idea.

[0027] For the same reason, in the accompanying drawings, some elements may be exaggerated, omitted, or schematically illustrated. Further, the size of each element does not completely reflect the actual size. In the drawings, identical or corresponding elements are provided with identical reference numerals or different reference numerals.

[0028] The advantages and features of the disclosure and ways to achieve them will be apparent by making reference to embodiments as described below in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments set forth below, but may be implemented in various different forms. The following embodiments are provided only to completely disclose the disclosure and inform those skilled in the art of the scope of the disclosure, and the disclosure is defined only by the scope of the appended claims. Throughout the specification, the same or like reference numerals designate the same or like elements. Furthermore, in describing the disclosure, a detailed description of known functions or constitution incorporated herein will be omitted in the case that it is determined that the description may make the subject matter of the disclosure unnecessarily unclear. The terms which will be described below are terms defined in consideration of the functions in the disclosure, and may be different according to users, intentions of the operators, or customs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

[0029] Herein, it will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, may be performed based on computer program instructions. These computer program instructions may be loaded collectively onto at least one processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which perform through any one of, or in any combination of, the at least one processor of the computer or other programmable data processing apparatus, create means for performing the functions specified in the flowchart block(s). These computer program instructions may also be stored in a non-transitory computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instruction means that perform the function specified in the flowchart block(s). The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable data processing apparatus to produce a computer executed process such that the instructions that perform on the computer or other programmable data processing apparatus provide steps for executing the functions specified in the flowchart block(s).

[0030] Further, each block may represent a module, segment, or portion of code, which includes one or more executable instructions for executing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks may occur out of the order. For example, two blocks(or functions) shown in succession may in fact be performed substantially concurrently or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved.

[0031] As used in embodiments of the disclosure, a "~unit" may refer to a software element or a hardware element, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), which performs a predetermined function. However, the term including the word "~unit" does not always have a meaning limited to software or hardware. The "~unit" may be constructed either to be stored in an addressable storage medium or to execute one or more processors. Therefore, the "~unit" includes, for example, software elements, object-oriented software elements, components such as class elements and task elements, processes, functions, properties, procedures, sub-routines, segments of a program code, drivers, firmware, micro-codes, circuits, data, database, data structures, tables, arrays, and parameters. The components and functions provided by the "~unit" may be either combined into a smaller number of components and a "~unit," or divided into additional components and a "~unit." Moreover, the components and "~units" may be implemented to reproduce one or more central processing units (CPUs) within a device or a security multimedia card. Further, in the embodiments, the "~unit" may include one or more processors.

[0032] It should be appreciated that the blocks in each flowchart and combinations of the flowcharts may be performed by one or more computer programs which include instructions. The entirety of the one or more computer programs may be stored in a single memory device or the one or more computer programs may be divided with different portions stored in different multiple memory devices.

[0033] Any of the functions or operations described herein can be processed by one processor or a combination of processors. The one processor or the combination of processors is circuitry performing processing and includes circuitry like an application processor (AP, e.g. a CPU), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a Wi-Fi chip, a Bluetooth® chip, a global positioning system (GPS) chip, a near field communication (NFC) chip, connectivity chips, a sensor controller, a touch controller, a finger-print sensor controller, a display driver integrated circuit (IC), an audio CODEC chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, a microprocessor unit (MPU), a system on chip (SoC), an IC, or the like.

[0034] It will be appreciated that various embodiments of the disclosure according to the claims and description in the specification can be realized in the form of hardware, software or a combination of hardware and software.

[0035] Any such software may be stored in non-transitory computer readable storage media. The non-transitory computer readable storage media store one or more computer programs (software modules), the one or more computer programs include computer-executable instructions that, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure.

[0036] Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like read only memory (ROM), whether erasable or rewritable or not, or in the form of memory such as, for example, random access memory (RAM), memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a compact disk (CD), digital versatile disc (DVD), magnetic disk or magnetic tape or the like. It will be appreciated that the storage devices and storage media are various embodiments of non-transitory machine-readable storage that are suitable for storing a computer program or computer programs comprising instructions that, when executed, implement various embodiments of the disclosure. Accordingly, various embodiments of the present disclosure may provide a program comprising code for implementing apparatus or a method as claimed in any one of the claims of this specification and a non-transitory machine-readable storage storing such a program.

[0037] Hereinafter, the determination of priority between A and B in the present disclosure may refer to various actions such as selecting the one having a higher priority based on a predefined priority rule and performing an operation corresponding thereto, or omitting or dropping an operation corresponding to the one having a lower priority.

[0038] Hereinafter, "A or B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0039] In addition, "at least one of A, B, and C" as described in the present disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0040] In addition, "at least one of A, B, or C" as described in the present disclosure may be understood to include A, or B, or C, or any combination of A, B, and C.

[0041] Furthermore, "A / B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0042] Furthermore, "A, B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0043] Furthermore, "A and B" as described in the present disclosure may be understood as "A and / or B," which may include A, or B, or both A and B.

[0044] Furthermore, "if condition A and condition B are satisfied," as described in the present disclosure, may not be limited to a case where both condition A and condition B are satisfied, but may be understood to include a case where either condition A or condition B is individually satisfied, both condition A and condition B are satisfied, or one or more additional conditions are satisfied in combination.

[0045] Furthermore, throughout this disclosure, ordinal terms such as "first," "second," "third," etc., (and similar qualifiers) are used merely to distinguish between different instances, occurrences, configurations, messages, stages, or aspects of elements, operations, or information as described herein. Unless the context clearly dictates otherwise, the use of such ordinal terms does not itself require that the elements, operations, or information distinguished by these terms be structurally different, numerically distinct, or substantively dissimilar. For example, a "first signal" and a "second signal" may refer to instances of the same signal transmitted at different times or containing the same core information despite minor variations, or they may refer to signals with different content or characteristics, depending on the specific context. Similarly, a "first value" and a "second value" may represent the same magnitude but measured or applied in different circumstances, or they may represent different magnitudes. The interpretation should be guided by the specific technical context, function, and relationship described in the relevant portion of the specification and claims.

[0046] Furthermore, the terms "first ~", "second ~", etc., as described in the present disclosure with respect to various elements (e.g., information, objects, operation, sequences, or the like), should not limit those elements. These terms may only be intended to distinguish one element from another, and may not be intended to indicate a specific order. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element.

[0047] Furthermore, even if "first ~" and "second ~" are described in the present disclosure, it may be understood that element(s) referred to by "first ~" and "second ~" may be the same or different. For example, in case of element(s) being information, first information and second information may both be same information and, in some cases, are separate and different information.

[0048] In addition, the terms "if ~" and "in case that ~" as used in the disclosure or claims may be interpreted to include the meanings of "when (or upon) ~," "in response to ~," "based on ~," or "according to ~," and may be used interchangeably with these expressions. In addition, expressions other than those exemplified herein may also be used, as long as they have substantially the same meaning and do not impair the technical features of the present disclosure.

[0049] For example, the physical layer signaling may be referred to as Layer 1 (L1) signaling and may include downlink control information (DCI). In addition, the higher layer signaling may include a medium access control (MAC) control message, a radio resource control (RRC) signaling message, a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as L3 (layer 3) signaling. It should be noted, however, that the higher layer signaling is not limited to the aforementioned examples.

[0050] In addition, the term "not perform" as used in the present disclosure or claims may, in context, be understood to mean that the corresponding step is omitted or skipped. Such a term may be replaced with other terms having the same or substantially equivalent meaning.

[0051] In addition, "transmitting a message including A and B" as described in the present disclosure, may be understood as encompassing both (i) transmitting A and B in a single message, and (ii) transmitting A and B separately via multiple messages (e.g., transmitting a first message including A and a second message including B). This interpretation may also apply to messages that include two or more items (e.g., A, B, C), transmitted either together or separately.

[0052] In addition, "transmitting a message including A and transmitting a message including B" may also be interpreted as transmitting a message including A and B in a single message.

[0053] In the specific embodiments of the present disclosure described below, terms or components included in the disclosure may be expressed in singular or plural form depending on the specific embodiments presented. However, such singular or plural expressions are selected appropriately for convenience of description, and the present disclosure is not limited to a singular or plural number of components. A component expressed in the plural form may be implemented as a single component, and a component expressed in the singular form may be implemented as multiple components.

[0054] The drawings or flowcharts described below illustrate exemplary methods that may be implemented according to the principles of the present disclosure, and various modifications may be made to the methods illustrated in the flowcharts of the present disclosure. For example, although illustrated as a series of steps, various steps in each drawing or flowchart may overlap, occur in parallel, occur in a different order, or be repeated. In other examples, any step may be omitted or replaced with another step.

[0055] The methods and apparatuses proposed in the embodiments of the present disclosure are not limited to each embodiment individually, but may also be applied in combination of all or some of the embodiments proposed in the disclosure. Therefore, the embodiments of the present disclosure may be modified and applied without significantly departing from the scope of the present disclosure, as would be understood by those skilled in the art.

[0056] In this case, even if certain wordings are described differently across embodiments, they may be used interchangeably or in substitution or in combination if their underlying concepts are equivalent. For example, for the same or equivalent concept, even if one embodiment uses the expression "A" and another embodiment uses the expression "B", such expressions may be understood interchangeably, in substitution, or in combination.

[0057] The terms used in the following description to refer to access nodes, network entities, messages, interfaces between network entities, various types of identification information, and the like, are provided merely for the convenience of explanation by way of example. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may also be used. Such terms may also be interchangeable with terms defined in any 3rd generation partnership project (3GPP) technical specifications (TS) where appropriate.

[0058] Hereinafter, a base station is an entity that allocates resources to terminals, and may be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a wireless access unit, a BS controller, or a node on a network.

[0059] Furthermore, the base station of the present disclosure may include a split architecture comprising a central unit (CU) and a distributed unit (DU). In this structure, the CU is configured to process the higher layers of the control and user planes, while the DU is configured to process lower-layer radio resource functions. The embodiments of the present disclosure may be equally applicable to 5G base station architectures in which such CU and DU functional splits are implemented.

[0060] A terminal may include a UE, a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing communication functions.

[0061] In the disclosure, a downlink (DL) refers to a radio link through which a BS transmits a signal to a UE, and an uplink (UL) refers to a radio link through which a UE transmits a signal to a BS.

[0062] Furthermore, hereinafter, 5th generation (5G) mobile communication technologies (e.g., 5G new radio (NR)), 6th generation (6G) mobile communication technologies may be described by way of example, but the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, newly evolved mobile communication systems developed after 5G and 6G may be included. Furthermore, based on determinations by those skilled in the art, the embodiments of the present disclosure may also be applied to other communication systems (e.g., Wi-Fi systems) through some modifications without significantly departing from the scope of the present disclosure

[0063] In the following description, the terms physical channel and signal may be used interchangeably with data or control signal. For example, the term physical downlink shared channel (PDSCH) refers to a physical channel through which data is transmitted, but the term PDSCH may also be used to refer to the data itself. That is, in the present disclosure, the expression "transmit a physical channel" may be interpreted as being equivalent to the expression "transmit data or a signal via a physical channel."

[0064] Hereinafter, in the context of the present disclosure, higher layer signaling may refer to signaling corresponding to at least one or any combination of the following: master information block (MIB), system information block (SIB) or SIB M (M = 1, 2, ...), radio resource control (RRC), or medium access control (MAC) control element (CE), or a non-access stratum (NAS) signaling message, or an application layer message. The RRC signaling message may be referred to as L3 (layer 3) signaling.

[0065] In addition, L1 signaling may refer to signaling corresponding to at least one or any combination of signaling techniques using the at least one or any combination of the following physical layer channels or signaling: physical downlink control channel (PDCCH), downlink control information (DCI), user equipment (UE)-specific DCI, group-common DCI, common DCI, scheduling DCI (e.g., DCI used for scheduling downlink or uplink data), non-scheduling DCI (e.g., DCI not used for scheduling downlink or uplink data) physical uplink control channel (PUCCH), or uplink control information (UCI). The L1 signaling message may be referred to as a physical layer signaling.

[0066] Hereinafter, the expression that information is configured by the BS, as used in the present disclosure or claims, may, in context, be understood to mean that the terminal receives the corresponding information from the BS via a physical layer signaling or a higher layer signaling. Such an expression may be replaced with other terms having the same or substantially equivalent meaning.

[0067] Hereinafter, the operational principle of the present disclosure will be described in detail with reference to the accompanying drawings.

[0068] National roaming services are vital for ensuring seamless connectivity, especially in areas where a primary network operator lacks coverage. However, allowing unrestricted use of Access Technologies (ATs) for national roamers may result in technical challenges including, but not limited to, interoperability issues, Quality of Service (QoS) concerns, network congestion concerns, and the like. In an embodiment, the terms AT-Type and AT may be used interchangeably and may represent at least one of the below: 5thGeneration (5G), 4thGeneration (4G), 3rdGeneration (3G), 2ndGeneration (2G), Evolved Packet System (EPS), 5thGeneration System (5GS), New Radio (NR) including, but not limited to, NR in unlicensed bands NR Low-Earth Orbit (LEO) satellite access, NR Medium Earth Orbit (MEO) satellite access, NR Geostationary (GEO) satellite access, NR (OTHERSAT) satellite access, NR Reduced Capability (RedCap), Evolved UMTS Terrestrial Radio Access (E-UTRA), E-UTRA in unlicensed bands, Narrowband (NB) Internet of Things (IoT) or NB-S1, Wideband (WB)-IoT, and Long-Term Evolution Machine Type Communication (LTE-M).

[0069] AT utilization control information in a User Equipment (UE) corresponds to the AT utilization control information received from a network node. Conventionally, as depicted inFigure 1A,a UE 106 may be registered on a Public Land Mobile Network (PLMN) depicted as current PLMN 104 and may receive AT utilization control information from a network node 102 only for the PLMN on which it is currently registered. However, there may be one or more equivalent PLMNs corresponding to the PLMN on which the UE is currently registered. In particular, the AT utilization control information provides information about restricted or allowed ATs in the current PLMN 104 and not in the one or more equivalent PLMNs. This leads to issues such as signalling overload when the UE tries to connect to an AT that is also restricted in an equivalent PLMN, because of lack of information.

[0070] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

[0071] The present disclosure relates to wireless communication. Particularly, but not exclusively, the present disclosure relates to a method and system for handling Radio Access Technologies (RAT) restrictions.

[0072] National roaming services are vital for ensuring seamless connectivity, especially in areas where a primary network operator lacks coverage. Allowing unrestricted use of Radio Access Technologies (RAT) for national roamers may result in technical challenges including but not limited to, interoperability issues, Quality of Service (QoS) concerns, network congestion concerns, and the like.

[0073] The terms Rat-Type RAT and AT are used interchangeably and have the same meaning and they represent at least one of the below: 5G (also referred as NG-RAN, satellite NG-RAN), 4G (also referred as E-UTRAN, satellite E-UTRAN), 3G (also referred as UTRAN), 2G (also referred as GERAN), 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 Internet of Things (IoT) or NB-S1, WB-IoT, and LTE-M.

[0074] In an embodiment, RAT restriction information in the UE corresponds to the RAT restriction information received from the network over the Non-Access Stratum (NAS) or any other message. In an embodiment, the RAT restriction information may be included in the access technology utilization control IE (information elements). In an embodiment, the solution which applies on the equivalent Public Land Mobile Network (PLMN) also applies on the EHPLMN. The EHPLMN is stored in the USIM / SIM while equivalent PLMN list is sent to the UE in the NAS message (e.g. registration accept message).

[0075] According to the existing technologies, there are no suitable cells in tracking area. Particularly, the UE requires to set the 5GS update status to 5U3 ROAMING NOT ALLOWED (while storing it). The UE may further delete any last visited registered Tracking Area Identity (TAI) and TAI list. If the UE is not registering or has not registered to the same PLMN over both 3rdGeneration Partnership Project (3GPP) access and non-3GPP access, the UE may additionally delete 5G-GUTI and ngKSI.

[0076] Thereafter, the UE may reset the registration attempt counter in case of the following conditions:

[0077] If the UE is not operating in SNPN access operation mode and the Forbidden TAI(s) for the list of "5GS forbidden tracking areas for roaming" IE is not included in the REGISTRATION REJECT message, the UE may store the current TAI in the list of "5GS forbidden tracking areas for roaming" and may further enter the state 5GMM-DEREGISTERED.LIMITED-SERVICE, and

[0078] If the REGISTRATION REJECT message is not integrity protected, the UE may memorize that the current TAI was stored in the list of "5GS forbidden tracking areas for roaming" for non-integrity protected NAS reject message; or

[0079] If the UE is operating in SNPN access operation mode, the UE may store the current TAI in the list of "5GS forbidden tracking areas for roaming" for the current SNPN and the selected entry of the "list of subscriber data" or the selected PLMN subscription and enter the state 5GMM-DEREGISTERED.LIMITEDSERVICE.

[0080] If the REGISTRATION REJECT message is not integrity protected, the UE may memorize that the current TAI was stored in the list of "5GS forbidden tracking areas for roaming" for the current SNPN and the selected entry of the "list of subscriber data" or the selected PLMN subscription, for non-integrity protected NAS reject message. The UE may further search for a suitable cell in another tracking area according to 3GPP TS 38.304 or 3GPP TS 36.304.

[0081] According to the existing technologies, the N1 mode is not allowed. Particularly, the UE may set the 5GS update status to 5U3 ROAMING NOT ALLOWED (while storing it). The UE may further delete any 5G-GUTI, last visited registered TAI, TAI list and ngKSI.

[0082] Thereafter, the UE may reset the registration attempt counter and may enter the state 5GMM-DEREGISTERED.LIMITEDSERVICE.

[0083] Particularly, if the message has been successfully integrity checked by the NAS, the UE may set:

[0084] ● the PLMN-specific N1 mode attempt counter for 3GPP access and the PLMN-specific N1 mode attempt counter for non-3GPP access for the corresponding PLMN in case of PLMN; or

[0085] ● the SNPN-specific attempt counter for 3GPP access for the current SNPN in case of SNPN and the SNPN-specific attempt counter for non-3GPP access for the current SNPN;

[0086] Accordingly, the UE is configured to disable the N1 mode capability for the specific access type for which the message was received.

[0087] If the message has been successfully integrity checked by the NAS, the UE may disable the N1 mode capability also for the other access type.

[0088] In an embodiment, a UE receives Radio Access Technologies (RAT) restriction information for a PLMN-1 where it is currently registered. The RAT restriction information may be shared to the UE in multiple ways. For an example:

[0089] ● PLMN-1: RAT-1, RAT-2 allowed (i.e. not-restricted) RAT, RAT-3 is restricted RAT or

[0090] ● PLMN1: RAT-3 is restricted RAT (this indicates that other RAT except RAT-3 supported by the UE is allowed) or

[0091] ● PLMN1: RAT-1, RAT-2 is allowed RAT (this indicates that other RAT except RAT-1 and RAT-2 supported by the UE is not allowed)

[0092] Thus, a first problem corresponds to a condition if RAT restriction information is for the registered PLMN only and there is equivalent PLMNs where network wants to apply restriction then existing state of art is unable to support this. Suppose PLMN-2 is Equivalent PLMN of PLMN-1 and PLMN-1 is only allowed for the RAT-1. In this case, if the UE registered on PLMN-1 does not receive the RAT restriction information for the equivalent PLMNs then UE may select the RAT which is not allowed for the equivalent PLMNs and initiate registration. This increases the signalling load.

[0093] A second problem corresponds to applying the RAT restriction information for the EPLMN (equivalent PLMN). The UE has the RAT restriction information for the registered PLMN (e.g., PLMN-1) and its equivalent PLMN (e.g., PLMN-2). Though the RAT restriction information is available, how to apply or avoid the reselection is not known as per the existing techniques.

[0094] A third problem corresponds to an instance when the UE considers RAT is disabled and receives the redirection.

[0095] In an embodiment, the UE is registered on PLMN-1 on RAT-1 (e.g., NG-RAN) and RAT-2 (e.g., E_UTRAN) is restricted. The UE, then receives cause 5GMM value #31 (e.g. in service reject message) to move the UE to other RAT (RAT-2). However, as per the RAT restriction information in the UE, RAT-2 is restricted. Thus, the UE may not be able to get the service. For example, the UE is registered on PLMN-1 on RAT-1: NR RAT (N1 mode). The UE may include the RAT restriction information and may consider the E-URTA as restricted. The UE receives the registration reject or service reject with 5GMM cause #31. In this case, Access and Mobility Management Function (AMF) indicates the UE to move to E-UTRA and disable N1 mode. This situation may arise when current AMF / network node where UE is registered is not capable of sending RAT restriction information. The UE has the stored RAT restriction information (e.g. received in EPC where MME / network node supports this feature or in other AMF where this feature is supported and the UE received the RAT restriction information). Therefore, this leads to the third problem as the E-UTRAN is restricted in the UE RAT restriction information. Thus, the UE may not be able to handle the reject cause #31 along with the registration reject / service reject. Similar problem would arise when the UE receives the EMM cause value #31 in EPC and N1 mode / NR RAT is restricted.

[0096] The present disclosure provides a method and system for handling Radio Access Technologies (RAT) restrictions. According to the present disclosure, there is a requirement to work on enhancements of Evolved Packet Service (EPS) and 5GS, such that RAT utilization restriction information and User Equipment (UE) behaviour are delivered to corresponding UE. It is further required to work on a criterion for re-enabling a previously disabled RAT.

[0097] As per the present disclosure, it is further required for a potential access restriction data update in:

[0098] ● a HLR to enable limitation of the RAT utilization performed at the SGSN.

[0099] ● a HSS to enable limitation of the RAT utilization performed at the Mobility Management Entity (MME).

[0100] ● a Unified Data Management (UDM) / UDR to enable limitation of the RAT utilization performed at the AMF.

[0101] In an embodiment, to solve the first problem, the network may include the RAT restriction information for the equivalent PLMNs as well (if available). Further, the same applies for the EHPLMN.

[0102] For example, the RAT restriction information may correspond to:

[0103] ● PLMN-1: Allowed (not restricted) or restricted RATs or combination of them.

[0104] ● PLMN-2: Allowed RAT (not restricted) or restricted RAT or combination of them.

[0105] ● PLMN-3: Allowed RAT (not restricted) or restricted RATs or combination of them.

[0106] Here PLMN-1 and PLMN-2 are equivalent PLMNs or EHPLMNs of PLMN-1 which is registered or current PLMN. Further, the combination of them corresponds to both allowed RATs (not restricted) and restricted RATs.

[0107] In an embodiment, the network may include but not limited to, Policy Control Function (PCF), MME, AMF, UDM / UDR and the like. In an embodiment, the UE may accept and store the RAT restriction information if the NAS message is integrity protected. If the NAS message is not integrity protected or failed integrity check, the UE may ignore the RAT restriction information. Optionally, if the UE receives the RAT restriction information for the PLMNs not in the list of equivalent PLMNs, then the UE may not consider the RAT restriction information for those PLMNs. Here, PLMN-3 is not equivalent PLMN of PLMN-1. Therefore, the UE will not update / store the RAT restriction information of PLMN-3 (for instance, if received on the downlink NAS message).

[0108] In an embodiment, the RAT restriction information is not shared for the equivalent PLMNs and the UE may hold the stored RAT restriction information for the EPLMN (e.g. PLMN-2), the UE uses the stored information which is received previously received.

[0109] In an embodiment, to solve the second problem, the present disclosure describes two solutions. The first solution for the second problem corresponds to an instance wherein the UE does not disable the UE capability and handles it locally.

[0110] In the first solution, the UE has the RAT restriction information for the registered PLMN (e.g. PLMN-1) and its equivalent PLMN (e.g. PLMN-2).

[0111] Further, when the UE has the RAT restriction information for the PLMN-1 and its equivalent PLMN i.e., PLMN-2 (either same or different), the UE does not disable the UE capability (including the UE radio access capability) for the restricted RAT. The UE still considers all the RAT is allowed, which is supported by the UE. The RAT restriction is used for the cell selection and cell reselection. In this case, when AS (Access Stratum also called lower layer) layer tries to find the candidate cell for the cell selection / reselection, it additionally checks if the PLMN is allowed in the RAT. If the PLMN is allowed in the RAT, then it only considers the cell / frequency as candidate cell / frequency and the UE reselects the corresponding cell / frequency. Here, the PLMN is allowed in the RAT corresponds to the current registered PLMN or its equivalent PLMN. In an embodiment, the NAS updates the AS layer (lower layer) with the RAT restriction information for the current PLMN (selected / registered PLMN) and its equivalent PLMN (if network indicated). In an embodiment, if the UE selects a PLMN on the RAT which is restricted due to the RAT restriction information in the UE, then the UE may not initiate registration request for normal service or procedure on 5G / N1 mode / NG-RAN cell (if NG-RAN is restricted). The UE may also not initiate attach request / tracking area update request or procedure when in the EPC or E-UTRAN cell (if E-UTRAN is restricted) as per the RAT restriction information. In an embodiment, if a RAT is restricted for the equivalent PLMNs, the UE may not consider the cell found in restricted RAT as a candidate cell / frequency for the cell selection and cell reselection for the equivalent PLMN (for instance, if the E-UTRA is restricted for the PLMN-2 then the UE may not consider the E-UTRA RAT / frequency for the cell selection / reselection for the PLMN-2, when the UE is registered on PLMN-1 and when PLMN-2 is equivalent PLMN).

[0112] The second solution for the second problem corresponds to an instance wherein the UE considers the RAT to be disabled for the UE capability.

[0113] In an embodiment, the UE has the RAT restriction information for the registered PLMN (e.g. PLMN-1) and its equivalent PLMN (e.g. PLMN-2).

[0114] Further, when the UE receives the RAT restriction information for the PLMN-1, it disables the UE capability for the RAT which is restricted. For instance, suppose E-UTRA is restricted on PLMN-1, the UE may not include E-UTRA capability in the registration request and E-UTRA radio capability may also be disabled. The UE includes the RAT restriction information for the equivalent PLMN which is PLMN-2. In this case, the UE uses the RAT restricted information for the cell selection / reselection. In an embodiment, if a RAT is restricted for the equivalent PLMNs, the UE may not consider the restricted RAT as a candidate for the cell selection and cell reselection for the equivalent PLMN (for instance, if E-UTRA is restricted for the PLMN-2, then the UE shall not consider the E-UTRA RAT for the cell selection / reselection for the PLMN-2 when the UE is registered on PLMN-1 and PLMN-2 is equivalent PLMN).

[0115] The solution for the third problem corresponds to an instance wherein the UE considers that the RAT is disabled and receives the redirection.

[0116] In an embodiment, the UE is registered on PLMN-1 on RAT-1 and RAT-2 is restricted. In step 2, the UE receives 5GMM / EMM cause value #31(e.g with service reject) to move UE to other RAT (RAT-2). However, as per the RAT restriction information in the UE, RAT-2 is restricted. The UE may not be able to get the service. Particularly, in step 2, the UE is in the NR / N1 mode and receives registration reject or service reject with 5GMM cause value #31 (wherein redirection to EPC required). If the EPC / EUTRAN / S1 mode is restricted as per the RAT restriction information in the UE, the UE considers that EPC / EUTRAN / S1 is not restricted. The UE further searches EUTRAN cell and registers on it. In an embodiment, additionally the UE marks the NR-RAT / N1 mode as restricted for the PLMN-1 in the RAT restriction information in the UE. In an embodiment, the UE additionally marks the E-UTRAN-RAT / EPC / S1 mode as not restricted for the PLMN-1 in the RAT restriction information in the UE (i.e. remove the E-UTRAN-RAT / EPC / S1 for PLMN-1 in the RAT restriction information in the UE). In an embodiment, when the UE receives downlink NAS message with cause #31 (e.g., with registration reject) then the current RAT where it is received, is marked as restricted and other RAT is marked as not restricted / allowed for the PLMN (here for the PLMN-1 where reject is received). In another embodiment, the UE supporting Cellular IoT (CIoT) optimizations may not use the RAT restriction information (i.e., UE doesn't indicate support of access technology utilization control (ATUC) in e.g. 5GMM capability IE included with registration request message). In an embodiment, the UE supporting CIoT optimizations may not indicate to the network support of access technology utilization control (ATUC) (in 5GMM / EMM capability IE or any other IE included in the NAS message registration request / tracking area request message etc. In an embodiment, when MME and AMF determine that UE support CIoT optimizations, it does not provide RAT restriction information.

[0117] In an embodiment, the UE may be unable to find the service on non-restricted RAT.

[0118] The problem here corresponds to as:

[0119] ● The UE includes the RAT restriction policy with RAT-1 as restricted for PLMN-1.

[0120] ● The UE searches for the service on other RAT on PLMN-1 and other PLMNs, however none are found. Therefore, the UE will move to NO service.

[0121] The solution for the above is as follows:

[0122] When the UE is unable to find service on un-restricted RAT on suitable / allowed PLMN then the UE may camp on the PLMN on restricted RAT. In this case, the UE may not initiate registration procedure when camp on 5G / N1 mode but corresponding (RAT 5G / N1 mode) is restricted or attach / Tracking area update request procedure when UE camp on EPC / E-UTRAN / S1 mode and the corresponding RAT (EPC / E-UTRAN / S1 mode) is restricted. The UE may initiate registration procure / attach or tracking area update procedure for the emergency service on the restricted RAT.

[0123] Further, when the UE is camped on the restricted RAT, the UE state may move to 5GMM-DEREGISTERED or EMM-REGISTERED with 5GMM / EMM Sub state to LIMITED SERCICE or PLMN-SEARCH. For an example, NG-RAN is restricted on PLMN-1 and the UE is camped to the NG-RAN cell then the 5GMM state change to 5GMM-REGISTERED.LIMITED-SERVICE (if the UE is already registered) or 5GMM-DEREGISTERED.LIMITED-SERVICE (if the UE is not registered).

[0124] Furthermore, when the UE is on the PLMN (PLMN-1) on the RAT which is restricted, the UE may periodically search for service on the PLMN (PLMN-1) on other RAT which is not restricted or other suitable PLMN of the automatic PLMN selection procedure and not select PLMN if the RAT is restricted.

[0125] In an embodiment, when the UE receive 5GMM cause #31 in the registration reject or service reject it perform below action:

[0126] #31 (Redirection to EPC required)

[0127] 5GMM cause #31 received by the UE that has not indicated support for CIoT optimizations or not indicated support for S1 mode or received by a UE over non-3GPP access is considered as an abnormal case. This cause value received from a cell belonging to an SNPN is considered as an abnormal case. The UE sets the 5GS update status to 5U3 ROAMING NOT ALLOWED (and also stores it) and deletes any 5G-GUTI, last visited registered TAI, TAI list and ngKSI. Additionally, the UE resets the registration attempt counter. The UE enables the E-UTRA capability if it was disabled, disable the N1 mode capability for 3GPP access enter the 5GMM-DEREGISTERED.NO-CELL-AVAILABLE. If the message was received via 3GPP access and the UE is operating in single-registration mode, the UE handles the EMM parameters EMM state, EPS update status, 4G-GUTI, TAI list, eKSI and attach attempt counter as specified in 3GPP　TS　24.301

[0015] for the case when the EPS attach procedure is rejected with the EMM cause with the same value.

[0128] In an embodiment the term EMM sublayer states are at least one of the below:

[0129] 1) EMM-NULL

[0130] 2) EMM-DEREGISTERED

[0131] a) EMM-DEREGISTERED.NORMAL-SERVICE

[0132] b) EMM-DEREGISTERED.LIMITED-SERVICE

[0133] c) EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH

[0134] d) EMM-DEREGISTERED.PLMN-SEARCH

[0135] e) EMM-DEREGISTERED.NO-IMSI

[0136] f) EMM-DEREGISTERED.ATTACH-NEEDED

[0137] g) EMM-DEREGISTERED.NO-CELL-AVAILABLE

[0138] h) EMM-DEREGISTERED.eCALL-INACTIVE

[0139] 3) EMM-REGISTERED-INITIATED

[0140] 4) EMM-REGISTERED

[0141] a) EMM-REGISTERED.NORMAL-SERVICE

[0142] b) EMM-REGISTERED.ATTEMPTING-TO-UPDATE

[0143] c) EMM-REGISTERED.LIMITED-SERVICE

[0144] d) EMM-REGISTERED.PLMN-SEARCH

[0145] e) EMM-REGISTERED.UPDATE-NEEDED

[0146] f) EMM-REGISTERED.NO-CELL-AVAILABLE

[0147] g) EMM-REGISTERED.ATTEMPTING-TO-UPDATE-MM

[0148] h) EMM-REGISTERED.IMSI-DETACH-INITIATED

[0149] 5) EMM-DEREGISTERED-INITIATED

[0150] 6) EMM-TRACKING-AREA-UPDATING-INITIATED

[0151] 7) EMM-SERVICE-REQUEST-INITIATED

[0152] The term5GMM sublayer statesin this embodiment are at least one of the below:

[0153] 1) 5GMM-NULL

[0154] 2) 5GMM-DEREGISTERED

[0155] a) 5GMM-DEREGISTERED.NORMAL-SERVICE

[0156] b) 5GMM-DEREGISTERED.LIMITED-SERVICE

[0157] c) 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION

[0158] d) 5GMM-DEREGISTERED.PLMN-SEARCH

[0159] e) 5GMM-DEREGISTERED.NO-SUPI

[0160] f) 5GMM-DEREGISTERED.NO-CELL-AVAILABLE

[0161] g) 5GMM-DEREGISTERED.eCALL-INACTIVE

[0162] h) 5GMM-DEREGISTERED.INITIAL-REGISTRATION-NEEDED

[0163] 3) 5GMM-REGISTERED-INITIATED

[0164] 4) 5GMM-REGISTERED

[0165] i) 5GMM-REGISTERED.NORMAL-SERVICE

[0166] j) 5GMM-REGISTERED.NON-ALLOWED-SERVICE

[0167] k) 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE

[0168] l) 5GMM-REGISTERED.LIMITED-SERVICE

[0169] m) 5GMM-REGISTERED.PLMN-SEARCH

[0170] n) 5GMM-REGISTERED.NO-CELL-AVAILABLE

[0171] o) 5GMM-REGISTERED.UPDATE-NEEDED

[0172] 5) 5GMM-DEREGISTERED-INITIATED

[0173] 6) 5GMM-SERVICE-REQUEST-INITIATED

[0174] 5GMM-IDLE mode:In this specification, if the term is used standalone, a UE in 5GMM-IDLE mode means the UE can be either in 5GMM-IDLE mode over 3GPP access or in 5GMM-IDLE mode over non-3GPP access.

[0175] 5GMM-CONNECTED mode:In this specification, if the term is used standalone, a UE in 5GMM-CONNECTED mode means the UE can be either in 5GMM-CONNECTED mode over 3GPP access or in 5GMM-CONNECTED mode over non-3GPP access.

[0176] 5GMM-IDLE mode over 3GPP access:A UE is in 5GMM-IDLE mode over 3GPP access when no N1 NAS signalling connection between the UE and Network (i.e. Network function e.g. AMF / SMF / UPF) over 3GPP access exists. The term 5GMM-IDLE mode over 3GPP access used in the present document corresponds to the term CM-IDLE state for 3GPP access used in 3GPP　TS　23.501.

[0177] 5GMM-CONNECTED mode over 3GPP access:A UE is in 5GMM-CONNECTED mode over 3GPP access when an N1 NAS signalling connection between the UE and Network (i.e. Network function e.g. AMF / SMF / UPF) over 3GPP access exists. The term 5GMM-CONNECTED mode over 3GPP access used in the present document corresponds to the term CM-CONNECTED state for 3GPP access used in 3GPP　TS　23.501.

[0178] Below are example list of NAS messages (and not limited to). For complete list refer to 3GPP TS 24.501 or 3GPP TS 24.301.

[0179] REGISTRATION REQUEST message;

[0180] DEREGISTRATION REQUEST message;

[0181] SERVICE REQUEST message; and

[0182] CONTROL PLANE SERVICE REQUEST.

[0183] IDENTITY REQUEST

[0184] AUTHENTICATION REQUEST;

[0185] AUTHENTICATION RESULT;

[0186] AUTHENTICATION REJECT;

[0187] REGISTRATION REJECT;

[0188] REGISTRATION ACCEPT;

[0189] DEREGISTRATION ACCEPT;

[0190] SERVICE REJECT;

[0191] SERVICE ACCEPT;

[0192] UE CONFIGURATION UPDATE command;

[0193] UE PARAMETERS UPDATE command.

[0194] Tracking area update request,

[0195] Tracking area update accept,

[0196] Attach request,

[0197] Attach accept,

[0198] GUTI reallocation command,

[0199] GUTI reallocation complete

[0200] Detach request,

[0201] Detach accept etc.

[0202] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0203] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure.

[0204] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a device or system or apparatus proceeded by "comprises...a" does not, without more constraints, preclude the existence of other elements or additional elements in the device or system or apparatus.

[0205] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

[0206] As described in the background section and as depicted in Figure 1A, in the current scenario, the UE 106 receives AT utilization control information from the network node 102 only for the current PLMN 104. In particular, the AT utilization control information provides information about restricted or allowed ATs in the current PLMN 104 and not in the one or more equivalent PLMNs. This leads to issues such as signalling overload when the UE tries to connect to an AT that is also restricted in an equivalent PLMN, because of lack of information. The present disclosure is targeted at solving the above-mentioned problem and a description of the proposed solution is described in the forthcoming paragraphs in conjunction with Figures 1B-7.

[0207] Figure 1B depicts an exemplary environment 100B in which the techniques of the present disclosure may be implemented. In particular, Figure 1B depicts a UE 114 and a Network Node (NN) 110. In an embodiment, the NN 110 may be a Mobility Management Entity (MME) in case of a 4G / Long Term Evolution (LTE) network. In another embodiment, the NN 110 may be an Access and Mobility Management Function (AMF) in case of a 5G network. Figure 1B further depicts that the UE 114 is registered on a Public Land Mobile Network (PLMN), depicted as current PLMN 112. Further, there also exist various PLMNs that are equivalent to the current PLMN 112, depicted as Equivalent PLMNs (EPLMNs) 112-1 - 112-n.

[0208] The UE 114 receives a Non-Access Stratum (NAS) message 116 from the NN 110. The NAS message 116 comprises an AT utilization control Information Element (IE) which comprises AT utilization control information associated with a plurality of ATs restricted or allowed on the current PLMN 112 and the one or more EPLMNs 112-1 - 112-n. In an embodiment, the network may send AT utilization control IE and may send indicate to the same AT restriction on the EPLMNs 112-1 - 112-n as the current PLMN 112 or may send AT utilization control information for the current PLMN 112 and the one or more EPLMNs 112-1 - 112-n. In an embodiment, AT utilization control IE included in the NAS message 116 contains the AT restriction information.

[0209] Exemplary AT utilization control IEs are depicted in tables 1 and 2 below -

[0210] [Table 1]　: Access technology utilization control information element

[0211]

[0212] [Table 2]: AT utilization control IE.

[0213]

[0214] A detailed description of how the UE handles the received AT restriction information is described in the forthcoming paragraphs in conjunction with Figures 2-7.

[0215] Figure 2 depicts a block diagram 200 of a NN for generating AT utilization control information, in accordance with an embodiment of the present disclosure. In particular, Figure 2 depicts a NN 202 comprising a communication interface 204, an Input / Output (I / O) module 206, a memory 208 and a processor 210. It shall be noted that, in some embodiments, the NN 202 may include more or fewer components than those depicted herein. The various components of the NN 202 may be implemented using hardware, software, firmware, or any combinations thereof. Further, the various components of the NN 202 may be operably coupled with each other. NN 202 may refer to a network entity 202.

[0216] The network entity 202 may include an entity (apparatus, device, or server, etc.) that performs one or more network functions (NFs) or a part of a network function constituting a core network (e.g., a 5th generation (5G) core (5GC)) in a communication system. In this case, multiple NFs may be implemented within a single network entity, or a single NF may be distributed and implemented across a plurality of network entities. In addition, when an NF is implemented within the network entity, the NF may be implemented in the form of software, and in such a case, a program for operating the NF may be stored in memory of the network entity 202. A single NF may be implemented by one or more instances, which may be deployed on the same network entity or distributed across multiple network entities to operate. The instance may be a software unit that logically executes a specific network function, and may be implemented in a form that is decoupled from physical hardware resources. Further, one or more NFs may be implemented in the form of one network slice to operate to satisfy specifications required by a particular service. The NF may include at least one of an access and mobility management function (AMF), a session management function (SMF), a local session management function (L-SMF), a user plane function (UPF), a local user plane function (L-UPF), a policy control function (PCF), a unified data management (UDM), a unified data repository (UDR), a network exposure function (NEF), a network repository function (NRF), an application function (AF), a network slice selection function (NSSF), a network data analytics function (NWDAF), a network slice admission control function (NSACF), an authentication server function (AUSF), or a data network (DN).

[0217] Further, Figure 3 depicts a block diagram of a UE for handling AT utilization control information, in accordance with an embodiment of the present disclosure. In particular, Figure 3 depicts a UE 302 comprising a communication interface 304, an Input / Output (I / O) module 306, a memory 308 and a processor 310. It shall be noted that, in some embodiments, the UE 302 may include more or fewer components than those depicted herein. The various components of the UE 302 may be implemented using hardware, software, firmware, or any combinations thereof. Further, the various components of the UE 302 may be operably coupled with each other.

[0218] In an embodiment, the memories 208 and 308 are capable of storing machine executable instructions. In an embodiment, the processors 210 and310 are embodied as executors of software instructions. As such, the processors 210 and310 are capable of executing the instructions stored in the memories 208, 308 respectively, to perform one or more operations described herein.

[0219] The memory 208 corresponds to a hardware storage device capable of temporarily or permanently storing information and may include one or more storage media. For example, the memory 208 may include a memory assembly including one or more storage media. For example, the one or more storage media may include permanent memory, such as a hard drive, flash memory, or read-only memory (ROM), semipermanent memory, such as random access memory (RAM), cache memory, or a combination thereof. The memory 208 may be electrically, operatively, or communicatively coupled to the processor 210 and may be accessed by the processor 210. The memory 208 may store a computer program, codes, or instructions executable by the processor210. According to an embodiment, a computer program, codes, or instructions executable by the processor 210 may be either stored in a single memory device or separated and distributedly stored in two or more memory devices. By executing the instructions stored in the memory 208, the processor 210 may perform various functions according to an embodiment of the disclosure. According to an embodiment of the disclosure, operations of the network entity 202 may be caused to be performed based on execution of instructions (or a computer program or codes) stored in the memory 208 by at least one processor (or processing circuitry) configured to execute the same individually, collectively, or in any combination thereof, based on processing circuitry that is not configured to execute instructions, and / or based on components of processing circuitry that is not configured to execute instructions.

[0220] The memory 308 corresponds to a hardware storage device capable of temporarily or permanently storing information and may include one or more storage media. For example, the memory 308 may include a memory assembly including one or more storage media. For example, the one or more storage media may include permanent memory, such as a hard drive, flash memory, or read-only memory (ROM), semipermanent memory, such as random access memory (RAM), cache memory, or a combination thereof. The memory 308 may be electrically, operatively, or communicatively coupled to the processor 310 and may be accessed by the processor 310. The memory 308 may store a computer program, codes, or instructions executable by the processor 310. According to an embodiment, a computer program, codes, or instructions executable by the processor 310 may be either stored in a single memory device or separated and distributedly stored in two or more memory devices. By executing the instructions stored in the memory 308, the processor 310 may perform various functions according to an embodiment of the disclosure. According to an embodiment of the disclosure, operations of the UE 302 may be caused to be performed based on execution of instructions (or a computer program or codes) stored in the memory 308 by at least one processor (or processing circuitry) configured to execute the same individually, collectively, or in any combination thereof, based on processing circuitry that is not configured to execute instructions, and / or based on components of processing circuitry that is not configured to execute instructions.

[0221] In one embodiment, the processors 210 and 310 may be embodied as multi-core processors, single core processors, or a combination of one or more multi-core processors and one or more single core processors. For example, the processors 210 and 310 may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a Digital Signal Processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including, a Microcontroller Unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like.

[0222] In an embodiment, the processors 210, 310 may include one or a plurality of processors. At this time, one or a 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).

[0223] The processor 210 may control general operations of the network entity 202 according to embodiments of the disclosure. The processor 210 may be implemented by one or more integrated circuit (or circuitry) (IC) chips and may execute various data processings. The processor 210 may include at least one electric circuit, and may execute instructions (or a program, codes, data, etc.) stored in the memory 208, individually, collectively or in any combination thereof. Further, the processor 210 may include a single-core processor or multi-core processor, and may include a processor assembly including a plurality of processing circuits (circuitry) according to a specific implementation scheme. Further, it should be noted that, according to another embodiment, in a case where NF is implemented in the form of an instance, the network function may be not necessarily configured by physical hardware. According to an embodiment, the processor 210 may be electrically, operatively, or communicatively coupled to the network interface 204 to control the network interface 204. The processor 210 may include at least one processor (or processing circuitry), and the at least one processor may perform the following operations individually, collectively or in any combination thereof. In a specific embodiment, at least a part of the processor 210 may be included in one chip and the other part of the processor 210 may be included in another chip. Otherwise, at least one processor may be included in another component, for example, the network interface 204 or the memory 208. The processor 210 may perform or control or cause an operation of the network entity 202 for executing at least one or a combination of methods according to embodiments of the disclosure. For example, the processor 210 may control operations of the network entity 202 for exchanging a control plane message or a user plane message with a UE, a BS, or other core network entities through wireless or wired communication, using various protocols (e.g., NAS protocol). To this end, the processor 210 may execute a computer program, codes, or instructions stored in the memory 208, so as to control other components of the network entity 202 to enable execution of various operations.

[0224] The processor 310 may control general operations of the UE 302 according to embodiments of the disclosure. The processor 310 may be implemented by one or more integrated circuit (or circuitry) (IC) chips and may execute various data processings. The processor 310 may include at least one electric circuit, and may execute instructions (or a program, codes, data, etc.) stored in the memory 308, individually, collectively or in any combination thereof. Further, the processor 310 may include a single-core processor or multi-core processor, and may include a processor assembly including a plurality of processing circuits (circuitry) according to a specific implementation scheme. The processor 310 may be electrically, operatively, or communicatively coupled to the transceiver(e.g. communication interface 304) to control the transceiver. The processor 310 may include at least one processor (or processing circuitry), and the at least one processor may perform the following operations individually, collectively or in any combination thereof. For example, the processor 310 may include a communication processor (CP) configured to control communication operations and an application processor (AP) configured to control execution of an upper layer (for example, an application layer). In a specific embodiment, at least a part of the processor 310 may be included in one chip and the other part of the processor 310 may be included in another chip. Otherwise, at least one processor may be included in another component, for example, the transceiver or the memory 308. The processor 310 may perform or control or cause an operation of the UE 302 for executing at least one or a combination of methods according to embodiments of the disclosure. To this end, the processor 310 may execute a computer program, codes, or instructions stored in the memory 308, so as to control other components of the UE 302 to enable execution of various operations.

[0225] In an embodiment, the processors 210, 310 are configured to perform various operations as depicted in Figures 4 and 5 and elaborated in detail in the upcoming paragraphs.

[0226] Figure 4 depicts a logic flow diagram 400 for generation of AT utilization control information for a UE, in accordance with an embodiment of the present disclosure. The logic flow diagram 400 is implemented by the processor 210 of the NN 202.

[0227] At block 402, the logic flow diagram 400 describes generation of AT utilization control information by the processor 210 of the NN 202. In an embodiment, the processor 202 may generate the AT utilization control information for the UE 302 to inform the UE 302 of the ATs restricted or allowed in the current PLMN 112 on which the UE 302 is currently registered and one or more EPLMNs 112-1 - 112-n corresponding to the current PLMN 112. In an embodiment, the current PLMN 112 may also be referred to as Home PLMN (HPLMN) and an equivalent PLMN (EPLMN) may thus be an equivalent Home PLMN (EHPLMN).

[0228] At block 404, the logic flow diagram 400 describes transmission of the generated AT utilization control information by the processor 210 to the UE 302. In an embodiment, the generated AT utilization control information is transmitted to the UE 302 in an AT utilization control Information Element (IE). Further, the AT utilization control IE is encased in a NAS message such as the NAS message 116 as depicted in Figure 1B.

[0229] Figure 5 depicts a logic flow diagram 500 for handling AT utilization control information, in accordance with an embodiment of the present disclosure. The logic flow diagram 500 is implemented by the processor 310 of the UE 302.

[0230] At block 502, the logic flow diagram 500 describes that the UE 302 receives AT utilization control IE from the NN 202. In an embodiment, NAS layer of the UE 302 may receive a NAS message from the NN 202 comprising the AT utilization control IE. Further, in an embodiment, the AT utilization control IE may comprise AT utilization control information associated with a plurality of ATs restricted or allowed (not restricted) on the current PLMN 112 and the one or more EPLMNs 112-1 - 112-n. For instance, the AT utilization control information may include the following information -

[0231] ● Current PLMN 112 - Allowed or restricted ATs or combination of them.

[0232] ● EPLMN 112-1 - Allowed or restricted ATs or combination of them.

[0233] ● EPLMN 112-2 - Allowed or restricted ATs or combination of them.

[0234] ● EPLMN 112-n - Allowed or restricted ATs or combination of them.

[0235] In an embodiment, the NAS message 116 may include at least one of: an ATTACH ACCEPT message, an ATTACH REJECT message, network initiated DETACH REQUEST message, TRACKING AREA UPDATE ACCEPT message, TRACKING AREA UPDATE REJECT message, a GUTI (Globally Unique Temporary Identifier) REALLOCATION COMMAND or a SERVICE REJECT message, registration ACCEPT message, registration REJECT message, UE configuration update command message.

[0236] At block 504, the logic flow diagram 500 describes determining whether the NAS message 116 is integrity protected. In an embodiment, determining whether the NAS message 116 is integrity protected or not is crucial as a fake entry in the NAS message 116 may block the network selection on the specific AT, which is actually allowed for the UE 302, thus denying service to the UE 302. If the result of the determination is No, i.e., if the NAS message 116 is not integrity protected or has failed integrity protection check, the logic flow diagram 500 proceeds to block 506. However, if the result of the determination is Yes, i.e., if the NAS message 116 is integrity protected or has successfully cleared the integrity protection check, the logic flow diagram 500 proceeds to block 508.

[0237] At block 506, the logic flow diagram 500 describes ignoring the NAS message 116 upon determining that the NAS message 116 is not integrity protected.

[0238] At block 508, the logic flow diagram 500 describes accepting the NAS message 116 upon determining that the NAS message 116 is integrity protected. Upon determining that the NAS message 116 is integrity protected, the logic flow diagram 500 may proceed to blocks 510 and 512.

[0239] At block 510, the logic flow diagram 500 describes storing the AT utilization control information present in the NAS message 116 (e.g., registration reject, optionally with EMM / 5GMM reject cause #15 No suitable cells in tracking area). In an embodiment, the UE 302 may store the AT utilization control information together with identifiers corresponding to the current PLMN 112 and the one or more EPLMNs 112-1 - 112-n.

[0240] In an embodiment, if the AT utilization control IE (optionally with the type of access technology utilization control set to "current PLMN" or "current PLMN and its equivalent PLMNs") is included in the REGISTRATION REJECT message and the message has been successfully integrity checked, the UE 302 shall store the received AT utilization control information together with the PLMN identity of the current PLMN 112 in the list of "PLMNs with associated access technology restrictions" otherwise, the UE shall ignore the Access technology utilization control IE.

[0241] In an embodiment, if the AT utilization control IE is present in the SERVICE REJECT message and the message is successfully integrity checked by the NAS; the UE shall store the received AT utilization control information together with the PLMN identity of the current PLMN 112 in the list of "PLMNs with associated access technology restrictions" and replace the previously stored one associated with the current PLMN 112, if any, with the newly received AT utilization control information; otherwise, the UE 302 shall ignore the AT utilization control IE.

[0242] In an embodiment, if the AT utilization control IE is present in ATTACH REJECT message or tracking area reject message (optionally, the type of access technology utilization control is set to "current PLMN" or current PLMN and its equivalent PLMNs) and the message is successfully integrity checked, the UE 302 shall store the received AT utilization control information together with the PLMN identity of the current PLMN 112 in the list of "PLMNs with associated access technology restrictions". Otherwise, the UE 302 shall ignore the AT utilization control IE.

[0243] In an embodiment, if the received AT utilization control information is applicable for the current PLMN 112 and the one or more EPLMNS 112-1 - 112-n, the AT utilization control information may be applied for the current PLMN 112 and the one or more EPLMNs 112-1 - 112-n to perform one of: PLMN selection, cell selection and cell reselection. However, if the AT utilization control information is not applicable for the one or more EPLMNs 112-1 - 112-n, then the UE 302 may store the AT utilization control information associated with the one or more EPLMNs 112-1 - 112-n, and use it during the power ON or when UE 302 is going to no service.

[0244] In an embodiment, if a Mobile station (MS) associated with the UE 302 supports AT utilization control, the MS may maintain a list of "PLMNs with associated AT restrictions". when the MS receives the AT utilization control information from the NN 110. In an embodiment, when the MS receives the access technology utilization control information from the NN 110:

[0245] - if the stored AT utilization control information is applicable for the PLMN from which it is received and its equivalent PLMNs the MS shall apply it for the PLMN from which it is received and its equivalent PLMNs in PLMN selection, cell selection and cell reselection;

[0246] - to prevent repeated attempts to obtain normal service on a restricted PLMN / access technology combination, the MS shall provide the list of "PLMNs with associated access technology restrictions" to lower layers to exclude the restricted access technologies for cell selection and cell reselection on this PLMN.

[0247] At block 512, the logic flow diagram 500 describes determining a candidate cell for one of: cell selection and cell reselection. In an embodiment, for determining a candidate cell, the AT utilization control information may be transmitted from the NAS layer to an Access Stratum (AS) layer (also referred as lower layer) of the UE 302. For determining the candidate cell, in one embodiment, the UE 302 may not disable UE capability (including UE radio access capability) for the restricted ATs. In particular, the UE 302 may still consider that all the ATs that are supported by the UE 302 are allowed. However, the AT utilization control information is used for cell selection and reselection. In this case, when the AS layer tries to find the candidate cell for the cell selection / reselection, it may additionally check if an EPLMN amongst the one or more EPLMNs 112-1 - 112-n is allowed in the AT. If the EPLMN is allowed (not restricted) in the AT, the AS layer considers the cell as the candidate cell for the cell selection or cell reselection. In particular, if the EPLMN is not allowed in the AT, the UE may not consider cell in the restricted AT as a candidate for the cell selection and cell reselection for the EPLMN, thereby reducing signalling overhead that may occur due to repeated attempts to connect to a restricted PLMN-AT combination. For instance, if the E-UTRAN is restricted for the EPLMN 112-1, then the UE 302 may not consider the cell found with EMPLMN 112-1 in E-UTRAN AT as candidate cell for the cell selection / reselection for the EPLMN 112-1.

[0248] Figure 6 depicts, by way of a flowchart, an exemplary method 600 of handling AT restrictions, in accordance with an embodiment of the present disclosure. The method 600 is implemented at the NN 202. The method 600 may comprise one or more steps. The method 600 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform particular functions or implement particular abstract data types.

[0249] Further, the order in which the method 600 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof.

[0250] At step 602, the method 600 may include generating, AT utilization control information for the UE 302. In an embodiment, the AT utilization control information comprises information of at least one of: a plurality of ATs restricted and allowed on the current PLMN 112 and the one or more EPLMNs 112-1 - 112-n associated with the UE 302.

[0251] At step 604, the method 600 may include transmitting the AT utilization control information to the UE 302 in the AT utilization control IE of the NAS message 116 for performing one of: cell selection and cell reselection.

[0252] Figure 7 depicts, by way of a flowchart, an exemplary method 700 of handling AT restrictions, in accordance with an embodiment of the present disclosure. The method 700 is implemented at the UE 302. The method 700 may comprise one or more steps. The method 700 may be described in the general context of computer executable instructions. Generally, computer executable instructions can include routines, programs, objects, components, data structures, procedures, modules, and functions, which perform particular functions or implement particular abstract data types.

[0253] Further, the order in which the method 700 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. Furthermore, the method can be implemented in any suitable hardware, software, firmware, or combination thereof.

[0254] At step 702, the method 700 may include receiving, from the NN 202, the NAS message 116 comprising the AT utilization control IE. In an exemplary aspect, the AT utilization control IE comprises AT utilization control information of at least one of: plurality of ATs restricted and allowed on the current PLMN 112 and one or more EPLMNs 112-1 - 112-n corresponding to the current PLMN 112.

[0255] At step 704, the method 700 may include determining a candidate cell for one of: cell selection and cell reselection based on the AT utilization control information.

[0256] Figure 8 illustrates a block diagram of an exemplary computer system 800 for implementing embodiments consistent with the present disclosure. In an embodiment, the computer system 800 may be used to implement the NN 202 and / or the UE 302. Thus, the computer system 800 may be used for handling AT restrictions in a wireless network. The computer system 800 may comprise a Central Processing Unit 804 (also referred as "CPU" or "processor"). The processor 804 may comprise at least one data processor. The processor 804 may include specialized processing units such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc.

[0257] The processor 804 may be disposed in communication with one or more input / output (I / O) devices (not shown) via I / O interface 802. The I / O interface 802 may employ communication protocols / methods such as, without limitation, audio, analog, digital, monoaural, RCA, stereo, IEEE (Institute of Electrical and Electronics Engineers) -1394, serial bus, universal serial bus (USB), infrared, PS / 2, BNC, coaxial, component, composite, digital visual interface (DVI), high-definition multimedia interface (HDMI), Radio Frequency (RF) antennas, S-Video, VGA, IEEE 1016.n / b / g / n / x, Bluetooth, cellular (e.g., code-division multiple access (CDMA), high-speed packet access (HSPA+), global system for mobile communications (GSM), long-term evolution (LTE), WiMAX, or the like), etc.

[0258] Using the I / O interface 802, the computer system 800 may communicate with one or more I / O devices. For example, the input device 820 may be an antenna, keyboard, mouse, joystick, (infrared) remote control, camera, card reader, fax machine, dongle, biometric reader, microphone, touch screen, touchpad, trackball, stylus, scanner, storage device, transceiver, video device / source, etc. The output device 822 may be a printer, fax machine, video display (e.g., cathode ray tube (CRT), liquid crystal display (LCD), light-emitting diode (LED), plasma, Plasma display panel (PDP), Organic light-emitting diode display (OLED) or the like), audio speaker, etc.

[0259] The processor 804 may be disposed in communication with the communication network 818 via a network interface 806. The network interface 806 may communicate with the communication network 818. The network interface 806 may employ connection protocols including, without limitation, direct connect, Ethernet (e.g., twisted pair 10 / 100 / 1000 Base T), transmission control protocol / internet protocol (TCP / IP), token ring, IEEE 1016.11a / b / g / n / x, etc. The communication network 818 may include, without limitation, a direct interconnection, local area network (LAN), wide area network (WAN), wireless network (e.g., using Wireless Application Protocol), the Internet, etc. The network interface 806 may employ connection protocols include, but not limited to, direct connect, Ethernet (e.g., twisted pair 10 / 100 / 1000 Base T), transmission control protocol / internet protocol (TCP / IP), token ring, IEEE 1016.11a / b / g / n / x, etc. The computer system 800 may be connected to a device 820 through the communication network 818. In an embodiment, the device 820 may be the NN 202, when the computer system is implemented as the UE 302. In another embodiment, the device 820 may be the UE 302, when the computer system is implemented as the NN 202.

[0260] The communication network 818 includes, but is not limited to, a direct interconnection, an e-commerce network, a peer to peer (P2P) network, local area network (LAN), wide area network (WAN), wireless network (e.g., using Wireless Application Protocol), the Internet, Wi-Fi, and such. The first network and the second network may either be a dedicated network or a shared network, which represents an association of the different types of networks that use a variety of protocols, for example, Hypertext Transfer Protocol (HTTP), Transmission Control Protocol / Internet Protocol (TCP / IP), Wireless Application Protocol (WAP), etc., to communicate with each other. Further, the first network and the second network may include a variety of network devices, including routers, bridges, servers, computing devices, storage devices, etc.

[0261] In some embodiments, the processor 804 may be disposed in communication with a memory 810 (e.g., RAM, ROM, etc. not shown in Figure 8) via a storage interface 808. The storage interface 808 may connect to memory 810 including, without limitation, memory drives, removable disc drives, etc., employing connection protocols such as serial advanced technology attachment (SATA), Integrated Drive Electronics (IDE), IEEE-1094, Universal Serial Bus (USB), fiber channel, Small Computer Systems Interface (SCSI), etc. The memory drives may further include a drum, magnetic disc drive, magneto-optical drive, optical drive, Redundant Array of Independent Discs (RAID), solid-state memory devices, solid-state drives, etc.

[0262] The memory 810 may store a collection of program or database components, including, without limitation, user interface 812, an operating system 814, web browser 816 etc. In some embodiments, computer system 800 may store user / application data, such as, the data, variables, records, etc., as described in this disclosure. Such databases may be implemented as fault-tolerant, relational, scalable, secure databases such as Oracle ® or Sybase®.

[0263] The operating system 814 may facilitate resource management and operation of the computer system 1000. Examples of operating systems include, without limitation, APPLE MACINTOSHROS X, UNIXR, UNIX-like system distributions (E.G., BERKELEY SOFTWARE DISTRIBUTIONTM(BSD), FREEBSDTM, NETBSDTM, OPENBSDTM, etc.), LINUX DISTRIBUTIONSTM(E.G., RED HATTM, UBUNTUTM, KUBUNTUTM, etc.), IBMTMOS / 2, MICROSOFTTMWINDOWSTM(XPTM, VISTATM / 7 / 8, 10 etc.), APPLERIOSTM, GOOGLERANDROIDTM, BLACKBERRYROS, or the like.

[0264] In some embodiments, the computer system 800 may implement the web browser 816 stored program component. The web browser 816 may be a hypertext viewing application, for example MICROSOFTRINTERNET EXPLORERTM, GOOGLERCHROMETM0, MOZILLARFIREFOXTM, APPLERSAFARITM, etc. Secure web browsing may be provided using Secure Hypertext Transport Protocol (HTTPS), Secure Sockets Layer (SSL), Transport Layer Security (TLS), etc. Web browsers 816 may utilize facilities such as AJAXTM, DHTMLTM, ADOBERFLASHTM, JAVASCRIPTTM, JAVATM, Application Programming Interfaces (APIs), etc. In some embodiments, the computer system 800 may implement a mail server (not shown in Figure) stored program component. The mail server may be an Internet mail server such as Microsoft Exchange, or the like. The mail server may utilize facilities such as ASPTM, ACTIVEXTM, ANSITMC++ / C#, MICROSOFTR, .NETTM, CGI SCRIPTSTM, JAVATM, JAVASCRIPTTM, PERLTM, PHPTM, PYTHONTM, WEBOBJECTSTM, etc. The mail server may utilize communication protocols such as Internet Message Access Protocol (IMAP), Messaging Application Programming Interface (MAPI), MICROSOFTRexchange, Post Office Protocol (POP), Simple Mail Transfer Protocol (SMTP), or the like. In some embodiments, the computer system 1000 may implement a mail client stored program component. The mail client (not shown in Figure) may be a mail viewing application, such as APPLERMAILTM, MICROSOFTRENTOURAGETM, MICROSOFTROUTLOOKTM, MOZILLARTHUNDERBIRDTM, etc.

[0265] Figure 9 illustrates a method 900 performed by a user equipment (UE) according to various embodiments of the disclosure.

[0266] In step 910, the UE receives, from a network entity, an access technology utilization control IE (Information Element) via a Non-Access Stratum (NAS) signalling.

[0267] In an embodiment, the access technology utilization control IE comprises access technology utilization control information for a current public land mobile network (PLMN) and at least one equivalent PLMN.

[0268] In an embodiment, the UE provides a list of PLMNs with associated access technology restrictions to lower layers.

[0269] In an embodiment, the UE apply the access technology utilization control information for the current PLMN and the at least one equivalent PLMN in a PLMN selection process, cell selection process and cell reselection process.

[0270] In an embodiment, the UE replaces a previously stored access technology utilization control information associated with the current PLMN with the received access technology utilization control information for the current PLMN and the at least one equivalent PLMN.

[0271] In an embodiment, in case that (i) the access technology utilization control IE is present in a SERVICE REJECT message, and (ii) the SERVICE REJECT message is successfully integrity checked by a NAS layer, the UE stores the received access technology utilization control information together with a PLMN identity of the current PLMN in a list of PLMN with associated access technology restrictions.

[0272] In an embodiment, in case that the SERVICE REJECT message is not successfully integrity checked by the NAS layer, the UE ignores the access technology utilization control IE.

[0273] In an embodiment, in case that (i) the access technology utilization control IE is present in a REGISTRATION REJECT message, a ATTACH REJECT message, or a TRACKING AREA UPDATE REJECT message , (ii) a type of access technology utilization control is set to "current PLMN", and (iii) the REGISTRATION REJECT message, the ATTACH REJECT message, or the TRACKING AREA UPDATE REJECT message is successfully integrity checked by a NAS layer, the UE stores access technology utilization control information together with a PLMN identity of the current PLMN in a list of PLMN with associated access technology restrictions.

[0274] In an embodiment, in case that the REGISTRATION REJECT message, the ATTACH REJECT message, or the TRACKING AREA UPDATE REJECT message is not successfully integrity checked by the NAS layer, the UE ignores the access technology utilization control IE.

[0275] Figure 10 illustrates a method 1000 performed by a network entity according to various embodiments of the disclosure. In FIG. 10, descriptions of contents overlapping with Fig. 10 is omitted.

[0276] In step 1010, the network entity transmits, to a user equipment (UE), an access technology utilization control IE (Information Element) via a Non-Access Stratum (NAS) signalling.

[0277] In an embodiment, the access technology utilization control IE comprises access technology utilization control information for a current public land mobile network (PLMN) and at least one equivalent PLMN.

[0278] The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0279] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

[0280] When a single device or article is described herein, it will be readily apparent that more than one device / article (whether or not they cooperate) may be used in place of a single device / article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device / article may be used in place of the more than one device or article, or a different number of devices / articles may be used instead of the shown number of devices. The functionality and / or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality / features. Thus, other embodiments of the invention need not include the device itself.

[0281] The steps of a method or algorithm described in the disclosure may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

[0282] In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Storage media may be any available media that can be accessed by a general purpose or special purpose computer. I n addition, computer-readable storage media may be provided in the form of non-transitory storage media. The 'non-transitory storage medium' is a tangible device and only means that it does not contain a signal (e.g., electromagnetic waves). This term does not distinguish a case in which data is stored semi-permanently in a storage medium from a case in which data is temporarily stored. For example, the non-transitory recording medium may include a buffer in which data is temporarily stored.

[0283] While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. Any of the above variation embodiments can be utilized independently or in combination with at least one other variation embodiment. The above flowchart(s) illustrate example methods that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the methods illustrated in the flowcharts herein. For example, while shown as a series of steps, various steps in each figure could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.

[0284] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[0285] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

[0286] In an embodiment, the present disclosure describes providing AT utilization control information to a UE for EPLMNs.

[0287] In an embodiment, the present disclosure describes techniques that enable a UE to effectively handle AT utilization control information corresponding to the EPLMNs for performing cell selection / reselection, thereby reducing the signaling overhead and reducing time to select allowed AT for the EPLMN, hence, lowering time to find the service.

[0288] Meanwhile, although specific embodiments of the present disclosure have been described in detail, various modifications may be made without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims and equivalents thereof.

Claims

1.A method performed by a user equipment (UE), comprising:receiving, from a network entity, an access technology utilization control IE (Information Element) via a Non-Access Stratum (NAS) signaling,wherein the access technology utilization control IE comprises access technology utilization control information for a current public land mobile network (PLMN) and at least one equivalent PLMN.2.The method of claim 1, further comprising:providing a list of PLMNs with associated access technology restrictions to lower layers.3.The method of claim 1, further comprising:applying the access technology utilization control information for the current PLMN and the at least one equivalent PLMN in a PLMN selection process, cell selection process and cell reselection process.4.The method of claim 1, further comprising:replacing a previously stored access technology utilization control information associated with the current PLMN with the received access technology utilization control information for the current PLMN and the at least one equivalent PLMN.5.The method of claim 1, further comprising:in case that(i) the access technology utilization control IE is present in a SERVICE REJECT message, and(ii) the SERVICE REJECT message is successfully integrity checked by a NAS layer,storing the received access technology utilization control information together with a PLMN identity of the current PLMN in a list of PLMN with associated access technology restrictions.6.The method of claim 5, further comprising:in case thatthe SERVICE REJECT message is not successfully integrity checked by the NAS layer,ignoring the access technology utilization control IE.7.The method of claim 1, further comprising:in case that(i) the access technology utilization control IE is present in a REGISTRATION REJECT message, a ATTACH REJECT message, or a TRACKING AREA UPDATE REJECT message ,(ii) a type of access technology utilization control is set to “current PLMN”, and(iii) the REGISTRATION REJECT message, the ATTACH REJECT message, or the TRACKING AREA UPDATE REJECT message is successfully integrity checked by a NAS layer,storing access technology utilization control information together with a PLMN identity of the current PLMN in a list of PLMN with associated access technology restrictions.8.The method of claim 7, further comprising:in case thatthe REGISTRATION REJECT message, the ATTACH REJECT message, or the TRACKING AREA UPDATE REJECT message is not successfully integrity checked by the NAS layer,ignoring the access technology utilization control IE.9.A method performed by a network entity, comprising:transmitting, to a user equipment (UE), an access technology utilization control IE (Information Element) via a Non-Access Stratum (NAS) signaling; andwherein the access technology utilization control IE comprises access technology utilization control information for a current public land mobile network (PLMN) and at least one equivalent PLMN.10.A user equipment (UE), comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andat least one memory, 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:receive, from a network entity, an access technology utilization control IE (Information Element) via a Non-Access Stratum (NAS) signaling,wherein the access technology utilization control IE comprises access technology utilization control information for a current public land mobile network (PLMN) and at least one equivalent PLMN.11.The UE of claim 10, the instructions further cause the UE to:provide a list of PLMNs with associated access technology restrictions to lower layers.12.The UE of claim 10, the instructions further cause the UE to:apply the access technology utilization control information for the current PLMN and the at least one equivalent PLMN in a PLMN selection process, cell selection process and cell reselection process.13.The UE of claim 10, the instructions further cause the UE to:replace a previously stored access technology utilization control information associated with the current PLMN with the received access technology utilization control information for the current PLMN and the at least one equivalent PLMN.14.The UE of claim 10, the instructions further cause the UE to:in case that(i) the access technology utilization control IE is present in a SERVICE REJECT message, and(ii) the SERVICE REJECT message is successfully integrity checked by a NAS layer,store the received access technology utilization control information together with a PLMN identity of the current PLMN in a list of PLMN with associated access technology restrictions; andin case thatthe SERVICE REJECT message is not successfully integrity checked by the NAS layer,ignore the access technology utilization control IE.15.A network entity, comprising:at least one transceiver;at least one processor communicatively coupled to the at least one transceiver; andat least one memory, 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 network entity to:transmit, to a user equipment (UE), an access technology utilization control IE (Information Element) via a Non-Access Stratum (NAS) signaling; andwherein the access technology utilization control IE comprises access technology utilization control information for a current public land mobile network (PLMN) and at least one equivalent PLMN.

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