Methods for idle and inactive mode operation in store and forward networks

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a user equipment (UE) in a wireless communications system, the method comprising: receiving indication information of one or more satellites providing one or more non-terrestrial network (NTN) store and forward (S&F) cells; receiving, from a network, satellite assistance information on at least one satellite; and performing an idle mode operation based on the received satellite assistance information.

Description

METHODS FOR IDLE AND INACTIVE MODE OPERATION IN STORE AND FORWARD NETWORKS

[0001] The present disclosure relates to methods and apparatus for idle and inactive mode operation in store and forward networks.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] In an embodiment of the disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided. In an embodiment of the disclosure, the method may comprise receiving indication information of one or more satellites providing one or more non-terrestrial network (NTN) store and forward (S&F) cells; receiving, from a network, satellite assistance information on at least one satellite; and performing an idle mode operation based on the received satellite assistance information.

[0009] In an embodiment of the disclosure, the performing of the idle mode operation may comprise performing the idle mode operation in coverage of the one or more satellites.

[0010] In an embodiment of the disclosure, the idle mode operation may be not performed outside coverage of the one or more satellite.

[0011] In an embodiment of the disclosure, the method may comprise: entering a power saving mode outside coverage of the one or more satellites; and waking up from the power saving mode in coverage of the one or more satellites.

[0012] In an embodiment of the disclosure, the receiving of the indication information of the one or more satellites may comprise receiving, from the network, a non-access stratum (NAS) message comprising the indication information of the one or more satellites.

[0013] In an embodiment of the disclosure, the NAS message may be received from a mobility management entity (MME) of the network.

[0014] In an embodiment of the disclosure, the satellite assistance information may be received in system information from the network.

[0015] In an embodiment of the disclosure, the satellite assistance information may comprise ephemeris information and service start time information.

[0016] In an embodiment of the disclosure, the method may comprise determining a coverage of the one or more satellites based on the satellite assistance information.

[0017] In an embodiment of the disclosure, the method may comprise transmitting, to the network, indication information of the at least one satellite on which the UE lacks satellite assistance information.

[0018] In an embodiment of the disclosure, the indication information of the at least one satellite on which the UE lacks satellite assistance information may be sent via a radio resource control (RRC) message.

[0019] In an embodiment of the disclosure, the method may comprise: receiving, from the network, a request to identify whether the UE lacks the satellite assistance information on the at least one satellite; and identifying whether the UE lacks the satellite assistance information on the at least one satellite.

[0020] In an embodiment of the disclosure, the indication information of the one or more satellites may comprise a list of one or more satellite identifiers (IDs).

[0021] In an embodiment of the disclosure, the idle mode operation may comprise performing measurement for cell selection in an idle mode.

[0022] In an embodiment of the disclosure, a user equipment (UE) in a wireless communication system is provided. In an embodiment of the disclosure, the UE may comprise a transceiver and at least one processor. In an embodiment of the disclosure, at least one processor may be configured to: receive indication information of one or more satellites providing one or more non-terrestrial network (NTN) store and forward (S&F) cells; receive, from a network, satellite assistance information on at least one satellite; and perform an idle mode operation based on the received satellite assistance information.

[0023] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings.

[0024] Embodiments / examples of the present disclosure are further described hereinafter with reference to the accompanying drawings, in which:

[0025] Figure 1 provides a diagram of an example non-terrestrial network (NTN) according to an embodiment of the disclosure;

[0026] Figure 2a provides a diagram illustrating discontinuous coverage in an NTN network according to an embodiment of the disclosure;

[0027] Figure 2b provides a diagram illustrating discontinuous coverage in an NTN network according to an embodiment of the disclosure;

[0028] Figure 3a provides a diagram illustrating an example of a full coverage NTN network according to an embodiment of the disclosure;

[0029] Figure 3b provides a diagram illustrating an example of a discontinuous coverage NTN network according to an embodiment of the disclosure;

[0030] Figure 3c provides a diagram illustrating an example of a store and forward (S&F) discontinuous coverage NTN network according to an embodiment of the disclosure;

[0031] Figure 4 provides a flow diagram illustrating an example of cell barring in an S&F network according to an embodiment of the disclosure;

[0032] Figure 5 provides a diagram illustrating enhancements to idle mode operation in an S&F network according to an embodiment of the disclosure;

[0033] Figure 6 provides a diagram illustrating an example provision of satellite information in an S&F network according to an embodiment of the disclosure;

[0034] Figure 7 provides a diagram illustrating an example provision of satellite information in an S&F network according to an embodiment of the disclosure;

[0035] Figure 8 provides a block diagram of an exemplary network entity / function according to an embodiment of the disclosure; and

[0036] Figure 9 provides a diagram illustrating an method performed by a UE according to an embodiment of the disclosure.

[0037] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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

[0075] 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."

[0076] 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.

[0077] 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.

[0078] 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.

[0079] Hereinafter, the operational principle of the present disclosure will be described in detail with reference to the accompanying drawings.

[0080] The following description of examples of the present disclosure, with reference to the accompanying drawings, is provided to assist in a comprehensive understanding of certain examples of the present disclosure. The description includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the examples described herein can be made without departing from the scope of the invention or disclosure.

[0081] The same or similar components may be designated by the same or similar reference numerals, although they may be illustrated in different drawings.

[0082] Detailed descriptions of techniques, structures, constructions, functions or processes known in the art may be omitted for clarity and conciseness, and to avoid obscuring the subject matter of the present disclosure.

[0083] The terms and words used herein are not limited to the bibliographical or standard meanings, but are merely used to enable a clear and consistent understanding of the disclosure.

[0084] Throughout the description of this specification, the words "comprise", "include" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other features, elements, components, integers, steps, processes, operations, functions, characteristics, properties and / or groups thereof.

[0085] Throughout the description of this specification, the singular form, for example "a", "an" and "the", encompasses the plural unless the context otherwise requires. For example, reference to "an object" includes reference to one or more of such objects.

[0086] Throughout the description, the expression "one or more of A, B and / or C" (or the like) should be seen to separately include all possible combinations, for example: A, B, C, A and B, A and C, A and B and C.

[0087] Throughout the description of this specification, language in the general form of "X for Y" (where Y is some action, process, operation, function, activity or step and X is some means for carrying out that action, process, operation, function, activity or step) encompasses means X adapted, configured or arranged specifically, but not necessarily exclusively, to do Y.

[0088] Features, elements, components, integers, steps, processes, operations, functions, characteristics, properties and / or groups thereof described or disclosed in conjunction with a particular aspect, embodiment or example are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

[0089] The following examples are applicable to, and use terminology associated with, 3GPP 4G (e.g., LTE) and / or 5G (e.g., NR). However, the skilled person will appreciate that the techniques disclosed herein are not limited to these examples or to 3GPP 4G (e.g., LTE) and / or 5G (e.g., NR), and may be applied in any suitable system or standard, for example one or more existing and / or future generation wireless communication systems or standards (e.g., B5G, 5G-Advanced, 6G etc.). The skilled person will appreciate that the techniquees disclosed herein may be applied in any existing or future releases of 3GPP 4G (e.g., LTE) and / or 5G (e.g., NR) and / or 5G Advanced and / or 6G, and / or (3GPP Release 17, 18, 19, 20, etc.) or any other relevant standard. For example, the functionality of the various network entities and other features disclosed herein may be applied to corresponding or equivalent entities or features in other communication systems or standards. Corresponding or equivalent entities or features may be regarded as entities or features that perform the same or similar role, function, operation or purpose within the network.

[0090] Furthermore. the following also applies to the present disclosure:

[0091] - The terms functionality / use-case / configuration / scenario / site may be used interchangeably.

[0092] - The terms model and model functionality may be used interchangeably.

[0093] - This disclosure also apply to non-3GPP entities.

[0094] - The concepts, proposals, solutions, methods, embodiments, figures, and / or examples, presented in this disclosure, would apply to various type of communication systems, such as 4G, 4G-Advanced, 5G, 5G-Advanced, and 6G.

[0095] A particular network entity may be implemented as a network element on dedicated hardware, as a software instance running on a dedicated hardware, and / or as a virtualised function instantiated on an appropriate platform, e.g. on a cloud infrastructure.

[0096] The skilled person will appreciate that the present disclosure is not limited to the specific examples disclosed herein. For example:

[0097] - The techniques disclosed herein are not limited to 3GPP 4G or 5G or 5G-Advanced and also apply to B5G and 6G systems.

[0098] - One or more entities in the examples disclosed herein may be replaced with one or more alternative entities performing equivalent or corresponding functions, processes or operations.

[0099] - One or more of the messages in the examples disclosed herein may be replaced with one or more alternative messages, signals or other type of information carriers that communicate equivalent or corresponding information.

[0100] - One or more further elements, entities and / or messages may be added to the examples disclosed herein.

[0101] - One or more non-essential elements, entities and / or messages may be omitted in certain examples.

[0102] - The functions, processes or operations of a particular entity in one example may be divided between two or more separate entities in an alternative example.

[0103] - The functions, processes or operations of two or more separate entities in one example may be performed by a single entity in an alternative example.

[0104] - Information carried by a particular message in one example may be carried by two or more separate messages in an alternative example.

[0105] - Information carried by two or more separate messages in one example may be carried by a single message in an alternative example.

[0106] - The order in which operations are performed may be modified, if possible, in alternative examples.

[0107] - The transmission of information between network entities is not limited to the specific form, type and / or order of messages described in relation to the examples disclosed herein.

[0108] Certain examples of the present disclosure may be provided in the form of an apparatus / device / network entity configured to perform one or more defined network functions and / or a method therefor. Such an apparatus / device / network entity may comprise one or more elements, for example one or more of receivers, transmitters, transceivers, processors, controllers, modules, units, and the like, each element configured to perform one or more corresponding processes, operations and / or method steps for implementing the techniques described herein. For example, an operation / function of X may be performed by a module configured to perform X (or an X-module). Certain examples of the present disclosure may be provided in the form of a system (e.g., a network) comprising one or more such apparatuses / devices / network entities, and / or a method therefor.

[0109] It will be appreciated that examples of the present disclosure may be realized in the form of hardware, software or a combination of hardware and software. Certain examples of the present disclosure may provide a computer program comprising instructions or code which, when executed, implement a method, system and / or apparatus in accordance with any aspect, example and / or embodiment disclosed herein. Certain embodiments of the present disclosure provide a machine-readable storage storing such a program.

[0110] The content of the following documents is referred to below and / or their content provides background information and context that the following disclosure should be considered in view of:

[0111] 3GPP TS 36.331 V18.2.0 July 2024

[0112] 3GPP TS 36.304 V18.2.0 July 2024

[0113] RP-202689, RAN Meeting #90 December 2020

[0114] RP-211557, RAN Meeting #91-e March 2021

[0115] RP-220953, RAN Meeting #95-e March 2022

[0116] RP-223519, RAN Meeting #98-e December 2022

[0117] RP-234077 RAN Meeting #102 December 2023

[0118] (Note: the example versions shown for each TS are non-limiting, other versions of the TS may be considered also)

[0119] Wireless or mobile (cellular) communications networks in which a mobile terminal (e.g., user equipment (UE), such as a mobile handset) communicates via a radio link with a network of base stations, or other wireless access points or nodes, have undergone rapid development through a number of generations. The 3rdGeneration Partnership Project (3GPP) design, specify and standardise technologies for mobile wireless communication networks. Fourth Generation (4G) and Fifth Generation (5G) systems are now widely deployed, and development of Sixth Generation (6G) Systems is in progress.

[0120] 3GPP standards for 4G systems include an Evolved Packet Core (EPC) and an Enhanced-UTRAN (E-UTRAN: an Enhanced Universal Terrestrial Radio Access Network). The E-UTRAN uses Long Term Evolution (LTE) radio technology. LTE is commonly used to refer to the whole system including both the EPC and the E-UTRAN, and LTE is used in this sense in the remainder of this document. LTE should also be taken to include LTE enhancements such as LTE Advanced and LTE Pro, which offer enhanced data rates compared to LTE.

[0121] In 5G systems a new air interface has been developed, which may be referred to as 5G New Radio (5G NR) or simply NR. NR is designed to support the wide variety of services and use case scenarios envisaged for 5G networks, though builds upon established LTE technologies. New frameworks and architectures are also being developed as part of 5G networks in order to increase the range of functionality and use cases available through 5G networks.

[0122] In recent years, Non-Terrestrial Network (NTN) networks have been considered and their operation integrated into 3GPP systems in order to enhance coverage and / or provide alternative coverage mechanisms. The adaptation of Internet of Things (IoT) devices for operation with NTNs is also being considered.

[0123] Internet of Things (IoT) Non-Terrestrial Networks (NTNs)

[0124] Internet of Things (IoT) NTN was a 3GPP study and work item in 3GPP release 17 to provide NTN access for E-UTRAN IoT devices (NB-IoT and LTE-M / eMTC) [RP-202689]. NR NTN was a work item in Rel-17 to specify adaptation to allow NR to function over NTN [RP-211557]. NTN access may be through Lower Earth Orbit (LEO), Medium Earth Orbit (MEO) and Geostationary Orbit (GEO), as well as through High-Altitude Platform Systems (HAPS).

[0125] Following the Work items in Release 17 there were work items to enhance NR NTN [RP-220953] and IoT NTN [RP-220979] in Release 18.

[0126] The work item description for IoT NTN Rel-19 is the following [RP-234077]:

[0127] -Support of Store&Forward (S&F) satellite operation with full eNB as regenerative payload, therefore:

[0128] - -Define the necessary enhancements into E-UTRAN (network & UE) to support S&F operation for delay-tolerant services [RAN3, RAN2, RAN4]

[0129] - --At least specify necessary enhancements e.g. related to S1 protocol, especially to address the feeder link switch over as needed [RAN3]

[0130] Note: Strive to minimise UE impact.

[0131] Note: Coordination with SA2 (Rel-19 SA2 led Sat-Arch ph3 SI) is needed on the detail requirements (e.g. traffic type, or QoS parameters for S&F), network architecture (e.g. whether consider (partial) core network on satellite) etc.; further coordination with CT1 might be required

[0132] -Support of Capacity enhancements for uplink

[0133] - -Study then specify, if beneficial, enhancements to enable multiplexing of multiple UEs (e.g. up to the min of 4 and the maximum allowed by the existing UL and DL signalling) in a single 3.75 kHz or 15 kHz subcarrier via orthogonal cover codes (OCC) for NPUSCH format 1 and NPRACH [RAN1, RAN2]

[0134] - --Multi-tone support for 15 kHz SCS should also be considered

[0135] Note: Impact of impairment shall be taken into account

[0136] - -Study and specify, if beneficial the following enhancements to reduce the necessary uplink and downlink signaling to complete an EDT transaction [RAN2]:

[0137] - --Msg3 transmission without msg1 / RAR

[0138] - --Efficient delivery (reduced overhead) of msg4 / RRCEarlyDataComplete

[0139] Figure 1 provides an illustration of an example NTN where a gateway (GW) 106 provides a feeder link 108 to a satellite 110 and the satellite provides an NTN cell 114 and an access link 112 to a device 116, such as a UE, within the NTN cell. The gateway may be connected to a gNB / eNB 104 which in turn is connected to a core network 102. The gateway 106 may be part of the gNB / eNB 104, separate to or partially integrated. Some of the functions of the gNB / eNB may also be implemented in the satellite 110 in some examples.

[0140] Narrowband Internet of Things and LTE-M

[0141] Narrowband Internet of Things (NB-IoT) is a 3GPP-defined network based on 4G E-UTRAN that supports ultra-low complexity devices with very narrow bandwidth that was introduced in 3GPP Release 13. The use case of NB-IoT is to serve massive IoT application, where requirements for instance are to support enhanced coverage, power-efficient operation and a massive number of devices. Some of the features introduced are:

[0142] - Support for enhanced coverage through low bandwidth and extreme amounts of repetitions.

[0143] - Power efficient operation by allowing the UE to sleep for very long times, relaxed requirements and more efficient signal to establish with a cell.

[0144] LTE-M (LTE-Machine) or eMTC (enhanced Machine Type Communication) is a 3GPP-defined network that is an extension of 4G E-UTRAN that supports low-complexity devices with more narrow bandwidths compared to normal LTE and further simplifications of procedures. Similarly to NB-IoT, the use case is to serve massive IoT, but with more capabilities. Instead of being an entirely new type of device with major air interface changes as in NB-IoT, the LTE-M inherits most features of a regular LTE device, but with some adaptations for low complexity considerations.

[0145] Idle and Inactive Mode Operation

[0146] RRC Idle mode (i.e. idle mode) and / or RRC inactive mode (i.e. inactive mode) mobility are based on a UE autonomously performing measurements and deciding according to some rules whether a UE shall re-select to another cell or not to camp on.

[0147] During cell selection, the UE identifies suitable cells, which is according to a cell suitability criteria based on signal strength and signal quality measurements. After identifying one or several suitable cells, the UE can choose any of them. For instance the UE can select the cell with the strongest signal strength and signal quality within a PLMN. Cell selection can be performed following PLMN selection (which may be after a UE is turned on), after being released by a network, or during the RRC re-establishment procedure and a number of other cases.

[0148] A cell may be classified into a number of different types of cells with respect to a UE. A suitable cell is a cell that fulfils the cell selection criteria, the cell is not barred etc. and is part of the tracking area of the UE - thus a normal type of cell. An acceptable cell is a cell on which the UE is only allowed to camp for specific reasons such as emergency cases, but the cell cannot be barred and the cell selection criteria need to be fulfilled. A UE only camps on such a cell if it cannot find a suitable cell. A reserved cell is a reserved cell if the system information indicates that it is reserved.

[0149] When camped on a cell, the UE shall perform the cell reselection procedures which includes searching and detecting cells and camping on a better or more suitable cell. In the cell reselection procedure, the UE searches intra-frequency cells, inter-frequencies cells and inter-RAT cells following the signalling by the serving cell. Each frequency (inter-RAT or intra-RAT) may have a specific cell reselection priority. The cell reselection algorithm is designed to ensure that the UE chooses a cell with highest priority, given that it is not barred or not not allowed to camp on. A UE shall always select an inter-frequency or inter-RAT cell with a higher priority over a lower priority cell. If frequencies of equal priority are detected, then the UE shall rank all of the cells, where the ranking metric is based on signal strength and signal quality measurements and then choose the best candidate. The UE then camps on the newly re-selected cell.

[0150] There are also certain rules on for how long a new cell shall be better than the serving cell before camping on the new cell. This parameter is called Treselection and can be specific for a RAT or for other cases. There are also thresholds for the signal strength and / or signal quality that may need to be fulfilled before selecting a new cell to camp on, which may depend on whether the cell is lower or higher priority, and depend on whether the cell is inter-frequency or inter-RAT.

[0151] As part of the idle mode and inactive mode procedures, the UE also checks whether a cell is barred or not. If a cell is barred, the UE is not allowed to connect to the cell, not allowed to camp or consider the cell for cell reselection. In 4G, the barring bit is signalled in SIB1 while in 5G NR, the barring bit is signalled in MIB.

[0152] Inter-RAT may be considered any other than the current RAT. As an example for 4G E-UTRA UE, the following may be considered inter-RAT: 2G, 3G, 4G NB-IoT, 5G NR or 6G.

[0153] Discontinuous Coverage

[0154] Discontinuous coverage is the scenario in which a LEO or MEO satellite network is not able to provide continuous coverage due to not having enough satellites to cover the whole earth and / or the coverage area of a satellite moving. As the coverage moves, this means that coverage will be on and off from the point of view of a UE. This is illustrated in Figures 2a and 2b where the reference signal received power (RSRP) of the UE 202 of satellite #1 204 that provides sat cell #1 and satellite #2 206 that provides sat cell #2 goes below a required threshold 208 thus not being able provide coverage to the UE 202 (i.e. the UE goes out of coverage). As an example, if there is only a single LEO satellite, the UE may see coverage as seldom as once every 24 hours for several minutes depending on the satellite coverage characteristics.

[0155] To allow for power saving when there is no coverage, the UE is allowed to power down and not perform any Access Stratum (AS) functionality, such as measuring and trying to detect cells, also known as idle mode tasks. For the UE to be able to know when there is coverage or not, the network signals long-term ephemeris parameters that allow the UE to predict future satellite passes up to several days in the future. This is then used when the UE stops perform idle mode tasks on NTNs. This ephemeris information is signalled in a new System information block (SIB) SIB32. In addition to ephemeris parameters, the network also signals coverage parameters that tells the UE how large the coverage is to better be able to estimate whether a satellite will provide coverage or not.

[0156] The SIB32 consists of the following:

[0157] -------------------------- 36.331 V18.2.0 --------------------------

[0158] - SystemInformationBlockType32

[0159] The IESystemInformationBlockType32contains satellite assistance information for prediction of discontinuous coverage.SystemInformationBlockType32is only signalled in a NTN cell.

[0160]

[0161]

[0162] Store and Forward Non-Terrestrial Networks

[0163] Store & Forward (S&F) allows satellites to store UE data and transmit it when connected to ground stations or UE. Therefore, S&F means a satellite providing an NTN cell does not require a simultaneous service link and feeder link in order to provide communications to a UE.

[0164] Although the concepts of NTN, S&F, RRC idle and inactive modes have previously been defined, their integration with one another and optimisation of their integrated operation requires further definition.

[0165] Non-Terrestrial and Store and Forward Networks

[0166] In Release 17 IoT NTN WI, the concept of discontinuous coverage was introduced. While discontinuous coverage allows for UE power savings in deployments where there are not enough satellites to cover the whole earth, there are still some basic issues in order to provide cost-effective IoT NTN solutions. The main issue is that the satellites providing discontinuous coverage still need to have connectivity with a ground gateway in order to perform any type of communication. If one only considers coverage, the amount of ground stations are still the same for a discontinuous coverage satellite network as a fully continuous coverage network. This can be seen in Figures 3a, 3b, and 3c.

[0167] Figure 3a shows a case of continuous coverage, where each satellite 307 is connected to one of the three ground stations (or ground gateways) 301, 303, 305 (note: numeral 307 is used for each of the twelve satellites illustrated in Figure 3a, but alternatively these satellites could be individually numbered 307-1, 307-2, ..., 307-n, where n is equal to the total number of satellites). A corresponding cell or coverage is shown for each satellite 307.

[0168] In Figure 3b, a case of discontinuous coverage is shown with only four satellites 317 (this number is arbitrarily chosen to demonstrate discontinuous coverage); however, three ground stations (or ground gateways) 311, 313, 315 are still provided, with each satellite 317 connected to one of the three base stations 311, 313, 315 (note: numeral 317 is used for each of the four satellites illustrated in Figure 3b, but alternatively these satellites could be individually numbered 317-1, 317-2, ..., 317-m, where m is equal to the total number of satellites). A corresponding cell or coverage is again shown for each satellite 317

[0169] In Figure 3c, a case of discontinuous coverage with store and forwarding (S&F) is shown, where the satellites 327 that are providing the discontinuous coverage only temporarily connect with a ground station / network, during which time data may communicated between the satellite and the ground station 321. For instance, the satellites may only be connected with a ground station when they are in certain regions and / or within range for example. In other words, S&F refers to providing a communication service for UEs under satellite coverage without a simultaneous active feeder link between the satellite and a ground station.

[0170] Among others, two notable aspects of an S&F cell or a satellite operating with S&F are as follows. One aspect is that the full base station, i.e. a regenerative architecture, is on the satellite. This means that the eNB or gNB is in the satellite, which is different from the first release of NTN, which introduced transparent payload. Another aspect is that either the full core network, or part of the core network is in the satellite to enable some type of communication. Altogether, since the cell does not have connectivity to the outer world, this would mean that communication with a server or application on earth would naturally be very slow or only suitable to single messages being reported, such as IoT applications.

[0171] Accordingly, one issue with an S&F cell is that among all options of different cells, such as terrestrial cells, NTN cells, discontinuous coverage NTN cell and S&F cells, it is likely that S&F cells will offer the lowest QoS. This is because NTN is already expected to provide lower QoS, and an S&F cell does not have full network connectivity. Therefore, an S&F cell should preferably be the cell of lowest priority. Due to these aspects of S&F cells, in this disclosure approaches for idle and inactive mode methods to allow an S&F cell to be well-integrated into a network given its characteristics.

[0172] Accordingly, the present disclosure provides approaches for idle mode and inactive mode operation in store and forward networks.

[0173] Terms including S&F Cell, Non-S&F Cell, NTN Cell, and TN Cell used in the present disclosure should taken in the following context.

[0174] S&F Cell: In the present disclosure, an S&F cell is a cell that either is capable of S&F operation with other network nodes and UEs, or temporarily operates as an S&F cell. While in the present disclosure the S&F cell may be seen as a permanent condition, it may also be that the S&F cell is something temporary when the S&F cell or any cell does not have ground network and / or full core network connectivity. This may imply that the S&F status changes. A cell may also be considered an S&F cell if the cell does not have ground network and / or full core network connectivity. In this instance, the condition "If the cell is an S&F cell", may taken as "if the cell does not have ground connectivity" or "if the S&F cell does not have full core network connectivity". This may imply that there is information that indicates when a cell may or may not have ground connectivity, which the UE may compute on its own. For instance the network may indicate times when the cell may be considered to operate and not operate (e.g. an end time) as an S&F cell. An S&F-cell may also be a cell that signals an indication that it is an S&F-cell. This may for instance be that it signals the barring indication (which may be barred, notBarred or any other indication).

[0175] Non-S&F Cell: Any cell that is not an S&F cell, or a cell that has ground connectivity, or full core network connectivity. This can be an NTN cell, a terrestrial cell, an ATG cell or similar and of any radio access technology.

[0176] NTN Cell: A cell that operates over NTN. This can also be defined as a cell that indicates the field cellBarred-NTN. This can be a 4G IoT NTN, 5G NR or 6G NTN cell. This category may also encompass S&F cells.

[0177] TN Cell: A non-NTN cell.

[0178] Further information on a number of concepts 4G and 5G and potential equivalents in 6G are set out below:

[0179] - 4G and 5G RRC connected state - UE having established a connection with a RAN, i.e. a cell, gNB or similar identity.

[0180] - Cell - This may be also be a different concept in a 6G system. For instance in a cell-less case a UE may attach, connect and be associated with a beam or other similar identity.

[0181] - RRC idle - UE not in a RRC connected state, i.e. not having established a connection. RRC idle also means that UE will be camping on a cell or similar identity and then performing measurements and evaluating to find a better cell or similar identity.

[0182] - 5G RRC inactive - UE in a state similar to RRC idle where the UE stores the RRC configuration and resumes the RRC connection using the configuration. The network also stores the UE context and uses it to restore the UE connection.

[0183] - 5G RRC procedures (RRC Setup, RRC Resume, RRC Re-establishment, RRC Reconfiguration) - Any procedure that aims to establish a connection with a cell, a gNB or similar identity. For instance a procedure that aims to establish a 5G-6G Dual Connectivity setting with a 5G and 6G cell.

[0184] - Random access - The process of synchronizing the MAC layer via sending a preamble and receiving a message that synchronizes the uplink, as well as following messages to resolve any contention.

[0185] - Radio Link Failure - Failure of the radio link, which may be a failure based on measured radio signals, or based on operation in the cell, such as a number of retransmissions, random access failures, the radio beams failing etc. After the radio link failure the UE may try to reselect to another cell and re-establish the RRC connection.

[0186] - Handover - Performing active mobility to another cell, gNB or similar identity.

[0187] - Releasing RRC connection - The UE is released via a messages such as RRC Release that releases the RRC connection the UE has to one or more cells. This may also include the UE

[0188] S&F Cell Barring and De-Prioritization

[0189] In some instance it may be beneficial to bar a "legacy" UE from connecting to a non-terrestrial Store and Forward cell. Such a legacy UE may be a UE not capable of performing Store and Forward operation due to not implementing the feature, or a UE choosing not to operate as such a UE. It can be considered known that barring a non-capable S&F UE is done by utilizing a barring operation that is understood by all legacy UEs, for instance in cellBarred in MIB (for 5G NR), cellBarred in SIB1 and SIB-NB (in E-UTRAN, eMTC and NB-IoT).

[0190] In an example of the present disclosure, a further condition is added to the possible barring conditions, by making the barring conditioned on whether the UE is able to detect other non-S&F cells. A motivation for this is that S&F cells are expected to deliver a single message (or a limited number of messages) and if there is the possibility to connect to any other cell (i.e. non-S&F cell), then such a cell should be selected. The other non-S&F cells can be other NTN cells, but may also be terrestrial cells. This other non-S&F cell may be within the same frequency, within the same RAT, or within a same PLMN. Whether this barring condition shall be used can be configured by the network but may also be configured by the UE. A number of examples of the condition during which a detected S&F cell (or S&F cells) may be considered barred (where each condition may be taken alone or in any combination) are as follows:

[0191] - UE considers the S&F cell barred if a non-S&F cell has been detected.

[0192] - UE considers the S&F cell barred if a non-S&F cell has been detected and the non-S&F cell is considered a suitable cell.

[0193] - - This may be important as a non-S&F cell shall not only be detected, but it shall also be considered a suitable cell, i.e. it needs to fulfill the suitability requirements which includes whether the cell selection criteria is fulfilled. The cell selection criteria may include determining whether the signal strength and signal quality is good enough according to some configured parameters.

[0194] - - The condition may also include whether the other non-S&F cells are barred or not. In other words, the UE may consider the S&F cell barred if a non-S&F cell has been detected that is a suitable cell and is not barred.

[0195] - UE considers the S&F cell barred if a non-S&F cell has been detected on the same frequency

[0196] - UE considers the S&F cell barred if a non-S&F cell has been detected in the same PLMN

[0197] - UE considers the S&F cell barred if cellBarred-S&F (or other appropriate indicator, field, or information) is set to 'condition' (or other appropriate predetermined value) and if a non-S&F cell has been detected

[0198] - - There may be an option to set a value condition in the cellBarred-S&F that indicates that the cell may be considered based on any of the conditions above or other non-specified conditions. This option may be in addition to other values of cellBarred-S&F, i.e. the values barred and notBarred.

[0199] - UE considers the S&F cell barred if a terrestrial cell has been detected in the same PLMN

[0200] - - A cell can be terrestrial if the cell does not broadcast cellBarred-NTN or another appropriate indicator.

[0201] - UE considers a cell broadcasting cellBarred-S&F barred if a cell has been detected that does not broadcast cellBarred-S&F.

[0202] Here and throughout this disclosure, content received from the network providing an indication or information may be referred to as indicators, information, fields, bits, information elements or any other suitable term. Furthermore, such content may be referred to as being included in a signal, information, or message received from the network. The term network may also be considered to include any non-UE entity, such as an eNB, base station, satellite, core network entity, RAN entity etc.

[0203] Figure 4 provides an example method at a UE for determining whether a detected S&F cell is barred.

[0204] In operation 402, the UE searches and measures one or more cells as part of a cell selection and / or cell reselection procedure, which may for example be performed when the UE is an idle mode.

[0205] In operation 404 the UE detects an S&F cell. If an S&F cell is not detected, the method may end and / or a conventional cell selection / reselection method performed.

[0206] In operation 406, the UE determines whether it has detected any other non-S&F cells.

[0207] If one or more non-S&F cells have been detected at operation 406, the UE considers the detected S&F cells barred at operation 408.

[0208] If no non-S&F cells have been detected at operation 406, the UE checks one or more further conditions to see whether the detected S&F cell(s) are barred at operation 410.

[0209] Although a primary barring condition of detecting a non-S&F cell is shown in Figure 4, the method is not limited to this and any of the conditions discussed herein may be used. For example, the other non-S&F cells may have to satisfy one or more other conditions in order for the S&F cell(s) to be barred. One or more further operations may also be introduced in the method of Figure 4 and / or operations combined and / or omitted, possible depending on the nature of the barring conditions being implemented.

[0210] If a condition to bar an S&F cell is based on whether there is a terrestrial network detected, the UE may consider the S&F cell to be barred temporarily, i.e. for a limited amount of time. This can for instance be 300 seconds, or may also be any time configured by the UE or network.

[0211] In some examples, even if one or more of the above barring conditions are not fulfilled, the UE may still consider whether the S&F cell is barred to be UE based on other factors, such as whether the S&F cell itself is signaling to be a barred cell, and / or whether the S&F is suitable. In other words, the S&F cell not being barred by the above conditions, does not necessarily mean that the S&F cell still not barred.

[0212] In some examples, an S&F cell may be deprioritized (i.e. as opposed to barred) in idle mode cell selection and / or cell reselection procedures. This deprioritization may operate by deprioritizing a specific S&F cell or the whole or part of the frequency on which an S&F cell is operating on.

[0213] In another example, the deprioritization may be implemented by deprioritizing a frequency if an S&F cell has been detected on the frequency. This means that if a UE detects an S&F cell, the UE considers the frequency to be deprioritized. Another way of expressing this is that a UE capable of S&F considers the frequency to be of the lowest priority if the UE detects an S&F cell on the frequency.

[0214] In another example, the UE may consider whether to deprioritize a S&F cell depending on whether a non-S&F cell has been detected. In other words, the UE may consider an S&F cell to be of the lowest (or lower) priority if the UE is able to detect other non-S&F cells. These non-S&F cells may be cells on the same frequency, on inter-frequencies, inter-RAT frequencies, or within the same PLMN. The non-S&F cells may be other non-terrestrial cells that do not operate S&F, or terrestrial cells. Such an approach can assist in preventing an S&F cell being selected if there ever is a better alternative.

[0215] In another example, the UE may also consider whether to deprioritize a frequency if an S&F cell is detected on the frequency and a non-S&F cell is detected on other intra-RAT frequencies and / or inter-RAT frequencies.

[0216] This deprioritization, i.e. the deprioritization of an S&F cell or a frequency with S&F cells detected, may be active for a certain time, such as 300 seconds or be configurable to any suitable time by the network or UE.

[0217] The prioritization may be specifically configured by the UE and / or the network. This can be a configurationprioritizeNonSF(or any other suitable information or indicator), which is signalled or configured either by the S&F cell, configured by other non-S&F cells, or configured by NAS (higher / upper layers). Examples of this can be:

[0218] - A UE capable of S&F shall consider an S&F cell configuredprioritizeNonSFto be of the lowest priority if the UE is able to detect other non-S&F cells on the same frequency, on inter-frequencies or inter-RAT frequencies.

[0219] - - In this case, each S&F cell may need to configure theprioritizeNonSF. This can allow for more flexibility whereby only certain S&F cells uses this mechanism. For instance if there are more capable S&F cells, then this allows for better differentiation.

[0220] - A UE capable of S&F and configured by upper layers to deprioritize S&F shall consider an S&F cell to be of the lowest priority if the UE is able to detect other non-S&F cells on the same frequency, on inter-frequencies or inter-RAT frequencies.

[0221] - A UE capable of S&F shall consider an S&F cell to be of the lowest priority if the UE is able to detect other non-S&F cells on the same frequency, on inter-frequencies or inter-RAT frequencies, if the UE has been configured withprioritizeNonSF(or other suitable indicator or information).

[0222] - - This can be configured with dedicated signalling from the previous cell, or it can be configured with dedicated signalling from a previous non-S&F cell.

[0223] The UE may also be configured to not be required to measure a frequency if the UE detects an S&F cell on a frequency. In this case, if the UE detects an S&F cell on a frequency, then instead of deprioritizing the frequency (or in addition), the UE is configured to not be required to measure the frequency.

[0224] In another example, one or more new parameters to select an S&F network are introduced. This can for instance be an S&F cell-specific:

[0225] - Cell reselection priority

[0226] - T-reselection RAT. For instance the UE would need to fulfill the reselection criteria for an S&F cell-specific amount of time in order to select an S&F cell to camp on.

[0227] - Srxlev (strength level) threshold for S&F measurements

[0228] The above may also apply to inter-RAT cell reselection. For instance if the UE has camped on a 5G NR terrestrial network and performs cell reselection and detects a 4G IoT S&F cell, then the above methods may apply. Similarly it may also apply if the UE camps on a 4G network and detects a 5G NR or 6G S&F cell. Furthermore, barring may be considered a specific type of prioritization, such that barring may be considered to fall within the scope of prioritization. More generally, any combination of cell types, frequencies, capabilities may be considered when determining S&F cell barrings and / or priorities.

[0229] Discontinuous Coverage and S&F Operation

[0230] Discontinuous coverage may be employed together with so-called S&F operation. There may for instance be an instances where some cells are operating as S&F with discontinuous coverage and some cells operate as non-S&F cells but with discontinuous coverage. For example, the non-S&F cells with discontinuous coverage may support legacy Release 17 UEs and S&F capable UEs, while the S&F cells support only S&F capable UEs.

[0231] In one example, the S&F-capable UEs may take into account the S&F cells in the discontinuous coverage operation. For instance, an S&F-capable UE may need to wake up to perform idle mode tasks when an S&F cell approaches. This could be different from legacy UEs, that may not have the ability to gain knowledge about S&F cells. Thus in some examples only S&F-capable UEs acquire S&F information and use the information in the discontinuous coverage operation.

[0232] Taking into account the S&F cells in the discontinuous coverage operation may comprise one or more actions.

[0233] In one example, a UE may determine whether it is in or out-of-coverage based on the coverage provided by S&F cells. In turn, based on such a determination, in some instances the UE may be allowed to not wake up from not performing any idle mode tasks, or be considered out-of-coverage based on the S&F cells (i.e. even if an S&F cell is available, the UE does not wake up). Such an example may occur when a UE has been provided information, such as information on specific satellites that the UE can connect to. This information can be from the upper layers, or from the RAN layers (for instance in an RRC connection release message) comprising satellite information. This satellite information may be satelliteIDs, which indicate the IDs of satellites, which may or may not be S&F satellites (however further information may also be provided such as an indication of whether a satellite is an S&F satellite). This may mean that even though there are satellites or cells, which may or may not be S&F satellites or cells, that pass over the UE, in which the UE may or may not normally be required to wake up to, the UE may not be required to wake up to perform idle mode tasks for these indicated satellites. The information from upper layers may be from MME or AMF or other entity in a NAS message. An example of this can be found in Example E and in Figure 5.

[0234] This may mean that the RAN broadcasts discontinuous coverage-related information, and the upper layers, for instance from MME via NAS, sends information that the UE uses to select certain elements of what RAN broadcasts and determines how to operate discontinuous coverage, i.e. how to determine when the UE shall perform idle mode tasks or to be considered out-of-coverage.

[0235] The idle mode tasks may be only the NTN idle mode tasks, i.e. performing measurements or similar on NTN cells, frequencies and RATs.

[0236] In Figure 5, a UE is signalled that it is to perform idle mode task only during coverage provided by S&F satellites 1 and 6 (SatelliteID=1 & SatelliteID=6), whereas otherwise the UE may also perform idle mode tasks during the coverage provided by S&F satellite 3 (SatelliteID=3). Consequently, by being provided by information on satellite coverage and / or information on satellites to ignore and / or a time range to ignore satellites, the UE may reduce the tasks it performs in idle mode, potentially reducing power consumption. In other words, the idle mode operations of the UE are not only determined by whether there is coverage but also (or alternatively) by the identity / functionality of the satellite that is providing the coverage. Although S&F satellites are considered in Figure 5, one or more of the satellites may non-S&F satellites.

[0237] With respect to signalling (e.g. broadcasting) the S&F-capable satellites, an indication of their identities may be provided in a separate list of satellites or cells, and not in the same list of satellites that provides the discontinuous coverage satellites. Thus the network may signal two lists of discontinuous coverage. One list consists of non-S&F cells or satellites, that are readable by a Release-17 discontinuous coverage-capable UE, and one list of cells or satellites that are readable by a S&F-capable UE, and also potentially discontinuous coverage-capable UEs. This can be seen in Example F. The benefit of this is that a UE that is not S&F-capable and should not connect nor camp on a S&F cell, such a UE will not be able to see the satellite info giving the ephemeris and coverage information of S&F satellites.

[0238] The satellite assistance information on the S&F-capable satellites may also be sent in a dedicated manner. This information and also other information concerning assistance information on S&F satellites may also be termed S&F (satellite) assistance information.

[0239] A list of satellite IDs for S&F satellites may also be provided via RRC connection release message. This can be useful if the core network is unable to send the suitable S&F satellites. It can be provided as part of a redirection message or as a message to just release the UE. This information is then saved by the UE in idle mode and then used to determine how long the UE will not perform any idle mode tasks, or stay out-of-coverage.

[0240] With the information on each satellite, the network may signal the time when the S&F-capable satellite does or does not have ground network or full core network connectivity. This may be provided when the satellite information for S&F satellites is broadcast or as part of RRC Release message. It may additionally or alternatively be useful to provide the information in a dedicated RRC release information. It can for instance be provided for one or two satellite IDs that are expected to pass by the UE earliest. In another example, the broadcast information or the dedicated information in an RRC connection release message may be provided to all UEs, and then the upper layer (for instance via NAS, which is signalling sent transparently from MME to UE) provides the satellite ID that is then used to determine when a UE is to wake up given the traffic requirements etc.

[0241] Missing S&F Satellite Assistance Information

[0242] If the upper layers, e.g. via NAS signalling, send a message containing one or more satellite IDs that the UE cannot identify as part of broadcasted or other received information, then there may be one or more different actions the UE may take. Such a situation may occur as the UE is about to be released to RRC idle or RRC inactive but is not only limited to these situations.

[0243] In one example, the UE may request satellite information from the network by sending a request with one or more satellite IDs. This request can be sent to the cell (or eNB / gNB), for instance via RRC, upon which the cell (or eNB / gNB) responds with the requested information, i.e. the satellite information. The trigger for this request may be that upper layers have configured or sent UEs satellite IDs for which the UE does not have complete satellite information. It may also be triggered if the UE has no information on any satellite IDs. The condition for requesting the information may thus be that if the UE has received satellite IDs or satellite information from upper layers and the UE does not have the associated satellite assistance information. The network may also or alternatively poll the UE to check if the UE has sufficient information on the satelliteIDs that the UE has been configured with from upper layers, i.e. network sends a request querying whether a UE has satellite assistance information on the satelliteIDs it has been configured with, and the UE replies with the status. This may be important as it can be difficult to ensure that the information sent by the eNB and the MME are synchronized. This approach is illustrated by Figure 6.

[0244] Figure 6 illustrates example signalling between a UE 602, S&F eNB 604 and an MME 606 in accordance with an example of the present disclosure where the UE determines whether it has (or lacks) information on indicated satellites.

[0245] In operation 610, the S&F eNB 604 broadcasts satellite assistance information for discontinuous coverage information and information on one or more S&F satellites, which is received by the UE. The satellite assistance information may include any form of information required for the UE to operate with a satellite.

[0246] In operation 612, the MME 606 transmits to the UE 602 a NAS message including one or more SatelliteIDs indicating satellites for one or more S&F cells. The indicated satellites may be satellites that the UE is to consider for coverage, to bar, to adapt idle operation based upon etc.

[0247] In operation 614, the UE 602 determines whether it lacks information on any of the one or more satellites indicated in the NAS message.

[0248] In operation 616, the UE 602 transmits a request to the S&F eNB 604 for information on the one or more satellites (e.g. by including satelliteIDs) that the UE 602 is lacking information on.

[0249] In operation 618, the S&F eNB 604 responds to the request by transmitting to the UE 602 information on the satellites indicated in the request. In some examples, only the information that the UE lacks may be transmitted, for instance, if the S&F eNB is aware of specific information the UE lacks (e.g. due to such information being signalled by the UE at operation 616).

[0250] In operation 620, the UE 602 utilises the satellite information obtained from operations 610 and / or 618 to determine out of coverage information or other parameters / conditions associated with the S&F satellites. For example, the UE may perform any of the operations described by this disclosure based on the satellite information.

[0251] The request (e.g. the request of operation 616) may be done through any RRC message, such as UEAssistanceInformation, UEInformationResponse, ULInformationTransfer or sent in an RRC -Complete message (RRC Setup Complete, RRC Connection Resume Complete, RRC Reestablishment Complete, RRC connection reconfiguration complete). The response (e.g. the response of operation 618) may be done via RRC Reconfiguration, DLInformationTransfer or similar. The response may also be sent in an RRC Connection Release message. This can be useful if the UE is about to be released. The response may also be sent in a dedicated system information delivery. The response may also be in the form of updated system information, thus the network will not specifically send dedicated response information, but rather just update the currently broadcasted system information.

[0252] Figure 6 is based upon the UE determining and requesting satellite information that it lacks. However, operations 614-618 may be based on the above described polling implementation. For example, between operations 612 and 614 the network may poll the UE of whether it lack information on any the satellites indicated at operation 612. In response the UE may perform operation 614 and then in place of 616, send a polling response indicating the information the UE lacks.

[0253] Although specific implementations have been described with reference to Figure 6, the underlying approach of identifying a lack of satellite (assistance) information on indicated satellites at the UE, indicating such a lack of information to the network (e.g. via a poll response or a request), and receiving the required satellite information from the network may be implemented using any suitable procedure.

[0254] In another example, the MME or AMF indicates to the S&F eNB which of the satelliteIDs that were indicated in a NAS message. The S&F eNB can then use this to send the missing satellite assistance information to the UE. The S&F eNB can do this as it is the S&F eNB that potentially broadcasts the S&F satellite assistance information, for instance in SIB32. In an alternative, the S&F eNB may not broadcast any information on S&F satellites, and thus the S&F eNB would send the information on all of the satelliteIDs sent from MME or AMF. Sending the missing satellite assistance information can be sent via RRC Reconfiguration, or for instance via RRC Connection Release. This approach is illustrated by Figure 7.

[0255] Figure 7 illustrates example signalling between a UE 702, S&F eNB 704 and an MME 706 in accordance with an example of the present disclosure where the S&F eNB determines satellite information the UE is lacking and transmits such information to the UE.

[0256] In operation 710, the S&F eNB 704 broadcasts satellite assistance information for discontinuous coverage information and information on one or more S&F satellites, which is received by the UE. The satellite assistance information may include any form of information required for the UE to operate with a satellite.

[0257] In operation 712, the MME 706 transmits to the UE 702 a NAS message including one or more SatelliteIDs indicating satellites for one or more S&F cells. The indicated satellites may be satellites that the UE is to consider for coverage, to bar, to adapt idle operation based upon etc.

[0258] In operation 714, the MME transmits to the S&F eNB an indication of the satellites indicated to the UE 702 in operation 712 (i.e. the satelliteIDs for S&F cells transmitted to the UE 702).

[0259] In operation 716, the S7F eNB 704 determines whether the UE 702 lacks information on any of the one or more satellites indicated in the NAS message. This determining operation may be based on the information broadcast in operation 710 or other information indicating what information has previously been provided to the UE from any network entity.

[0260] In operation 718, the S&F eNB 704 transmits to the UE 702 information on the satellites that it has been determined that the UE 702 lacks information on.

[0261] In operation 720, the UE 702 utilises the satellite information obtained from operations 710 and / or 718 to determine out of coverage information or other parameters / conditions associated with the S&F satellites. For example, the UE may perform any of the operations described by this disclosure based on the satellite information.

[0262] The indication from MME or AMF on the satelliteIDs that were indicated for S&F cells can be sent in a message that releases the UE. For instance UE context suspend, UE context release or similar.

[0263] In another example similar to that illustrated in Figure 7, the MME sends the full satellite assistance information to S&F eNB, which is then delivered to the UE, i.e. sent from the S&F eNB to the UE. Thus the MME first sends the satelliteIDs to UE, and then sends the full satellite assistance information to the S&F eNB, which then delivers this to the UE, for instance in an RRC release message.

[0264] In another example, the UE may assume that the satellite is upcoming and will thus try to acquire more system information from a cell, either from the current satellite it is connected or camping on, or on cells associated with upcoming satellite passes.

[0265] Other Idle Mode Operations

[0266] In another example, the UE shall not camp or shall deprioritize an S&F cell in case of emergency situations or other high priority situations. This may be important as the S&F cell may for instance not be able to serve a UE adequately during emergency situations, because the S&F cell does not have any ground connectivity. In these situations the UE shall prioritize any other type of cell, for instance an NTN cell with worse signal quality or cell or frequency priority. Such deprioritization may also be manually configured (i.e. turned and off) at the UE.

[0267] In another example, a UE shall consider an S&F cell to not support any emergency services. An example of this can be that if a cell indicates that it is an S&F cell, the UE assumes that IMS emergency services are not supported.

[0268] The above may for instance be achieved if the UE does not consider to camp on an S&F cell if the S&F cell is an acceptable cell.

[0269] In another example, an S&F cell or network shall indicate that it does not support IMS emergency services. This can for instance be done by not setting the IMS emergencySupport bit (i.e. indicator) in system information such as SIB1. This means that an S&F cell may not include or set the ims-EmergencySupport. An S&F cell may also be required to indicate that it does not support eCell over IMS in a similar manner.

[0270] In another example, if an S&F cell have some type of signaling to indicate when it has ground connectivity or full core network connectivity, the UE may use this information to compute whether the S&F cell supports IMS emergency services.

[0271] If for instance the S&F cell indicates via a single bit that it does not have ground connectivity or full core network connectivity, the UE will use this to consider the cell to not support IMS emergency services. And when the single bit indicates that ground connectivity or full network connectivity is restored, the UE considers the cell to support IMS emergency services.

[0272] In another example, if the S&F cell broadcasted more advanced information, such as time when cell has or does not have ground connectivity or full core network connectivity, the UE uses this time to determine when the cell supports IMS emergency services. If similarly any assistance information such as geometrical information is provided to determine whether the S&F cell has ground connectivity or full core network connectivity, the UE uses this information to do the determination.

[0273] The broadcast of the S&F barring bit may also be used. For instance if the barring bit is set with notBarred, the UE may still consider the IMS emergency services to not be supported, if the presence of the barring bit is used to indicate the S&F cell, or if the S&F cell has ground connectivity or full core network connectivity.

[0274] If the UE initiates a call, for instance an IMS call, the UE shall not camp on an S&F cell, and if a call is initiated, then UE shall reselect to a non-S&F cell.

[0275] Example 3GPP Specification Modification

[0276] In view of the examples set out above, the following provides example additions / adaptations that may be introduced into the 3GPP specification, where the highlighted parts represent some of the additions / adaptations.

[0277] Example A

[0278] ----------------- 36.331 Example -----------------

[0279] - SystemInformationBlockType1

[0280] SystemInformationBlockType1contains information relevant when evaluating if a UE is allowed to access a cell and defines the scheduling of other system information.SystemInformationBlockType1-BRuses the same structure asSystemInformationBlockType1.

[0281] Signalling radio bearer: N / A

[0282] RLC-SAP: TM

[0283] Logical channels: BCCH and BR-BCCH

[0284] Direction: E-UTRAN to UE

[0285]

[0286]

[0287] ----------------- 36.331 Example -----------------

[0288] Example B

[0289] ----------------- 36.304 Example -----------------

[0290] 5.3.1 Cell status and cell reservations

[0291] Cell status and cell reservations are indicated in theSystemInformationBlockType1message (orSystemInformationBlockType1-BRmessage orSystemInformationBlockType1-NBmessage) TS 36.331 [3] by means of the following fields:

[0292] -cellBarred(IE type: "barred" or "not barred")

[0293] This field indicates if the cell is barred for connectivity to EPC.

[0294] This field is ignored by the UEs supportingcrs-IntfMitigwhilecrs-IntfMitigEnabledis included in SIB1.

[0295] This field is ignored by the BL UEs or UEs in CE supportingce-CRS-IntfMitigwhilecrs-IntfMigitNumPRBsis included in SIB1-BR.

[0296] This field is ignored by UEs supporting NTN whilecellBarred-NTNis included in SIB1-BR or SIB1-NB.

[0297] In case of multiple EPC PLMNs indicated in SIB1 / SIB1-BR, this field is common for all EPC PLMNs

[0298] NOTE 1: IAB-MT ignores thecellBarred,cellReservedForOperatorUse,intraFreqReselectionandcsg-Indication(i.e. treatsintraFreqReselectionas if it was set toallowedand thecsg-Indicationas if it was set toFALSE) as defined in TS 36.331 [3].

[0299] -cellBarred-5GC(IE type: "barred" or "not barred")

[0300] This field indicates if the cell is barred for connectivity to 5GC.

[0301] This field is ignored if the UE does not support E-UTRA connected to 5GC or if the UE supports network-based CRS interference mitigation andnw-BasedCRS-InterferenceMitigationis included inSystemInformationBlockType1.

[0302] In case of multiple 5GC PLMNs indicated in SIB1, this field is common for all 5GC PLMNs.

[0303] -cellReservedForOperatorUse(IE type: "reserved" or "not reserved")

[0304] This field indicates if the cell is reserved for operator use.

[0305] This field is ignored by the UEs supportingcrs-IntfMitigwhilecrs-IntfMitigEnabledis included in SIB1.

[0306] This field is ignored by the BL UEs or UEs in CE supportingce-CRS-IntfMitigwhilecrs-IntfMigitNumPRBsis included in SIB1-BR.

[0307] In case of multiple EPC or 5GC PLMNs indicated in SIB1 / SIB1-BR, this field is specified per EPC or 5GC PLMN.

[0308] -cellBarred-CRS(IE type: "barred" or "not barred")

[0309] This field indicates if the cell is barred for connectivity to EPC for UEs supporting network-based CRS interference mitigation.

[0310] barredmeans the cell is barred for UEs supportingcrs-IntfMitigwhilecrs-IntfMitigEnabledis included in SIB1. For BL UEs or UEs in CE capable ofce-CRS-IntfMitig,barredmeans the cell is barred whilecrs-IntfMitigNumPRBsis included in SIB1-BR.

[0311] This field is ignored by the UE if the UE does not support CRS interference mitigation or whilecrs-IntfMitigConfigis not included in SIB1 (SIB1-BR for BL UEs or UEs in CE).

[0312] In case of multiple PLMNs indicated in SIB1 / SIB1-BR, this field is common for all PLMNs.

[0313] -cellBarred-5GC-CRS(IE type: "barred" or "not barred")

[0314] This field indicates if the cell is barred for connectivity to 5GC for UEs supporting network-based CRS interference mitigation.

[0315] This field is ignored if the UE does not support E-UTRA connected to 5GC or network-based CRS interference mitigation.

[0316] In case of multiple 5GC PLMNs indicated in SIB1, this field is common for all 5GC PLMNs.

[0317] -cellReservedForOperatorUse-CRS(IE type: "reserved" or "not reserved")

[0318] This field indicates if the cell is reserved for operator use for UEs supporting network-based CRS interference mitigation.

[0319] reservedmeans the cell is "reserved" for operator use for UEs supportingcrs-IntfMitigwhilecrs-IntfMitigEnabledis included in SIB1.

[0320] For BL UEs or UEs in CE capable ofce-CRS-IntfMitig,reservedmeans the cell is "reserved" for operator use whilecrs-IntfMitigNumPRBsis included in SIB1-BR.

[0321] This field is ignored if the UE does not support CRS interference mitigation or whilecrs-IntfMitigConfigis not included in SIB1 (SIB1-BR for BL UEs or UEs in CE).

[0322] In case of multiple PLMNs indicated in SIB1 / SIB1-BR, this field is specified per PLMN.

[0323] -iab-Support(IE type: "true")

[0324] Indicated inSIB1message. In case of multiple PLMNs indicated inSIB1, this field is specified per PLMN. This field indicates if the cell is barred for IAB node or the cell does not support IAB node, or both. When this field is absent, the IAB node shall treat this cell as if cell status is barred.

[0325] -cellBarred-NTN(IE type: "barred" or "not barred")

[0326] This field indicates if the cell is barred for connectivity to EPC via NTN.

[0327] This field is ignored if the UE does not support NTN connectivity.

[0328] The following description for handling of barred and reserved cells is per CN type. If the UE supports more than one CN type, the UE shall only exclude a cell as candidate for selection / reselection if it is excluded for both CN types.

[0329] NOTE 2: FieldscellBarred-CRSandcellReservedForOperatorUse-CRSare not indicated inSystemInformationBlockType1-NB

[0330] When cell status is indicated as "not barred" and "not reserved" for operator use,

[0331] - If the cell is indicated as an S&F cell, and if a non-S&F cell is detected and considered a suitable cell:

[0332] - - The UE shall consider the cell as barred

[0333] - else:

[0334] - - All UEs shall treat this cell as candidate during the cell selection and cell reselection procedures.

[0335] When cell status is indicated as "not barred" and "reserved" for operator use for any PLMN,

[0336] - UEs assigned to Access Class 11 or 15 (or corresponding Access Identity) operating in their HPLMN / EHPLMN shall treat this cell as candidate during the cell selection and reselection procedures if the fieldcellReservedForOperatorUsefor that PLMN set to "reserved".

[0337] - UEs assigned to an Access Class in the range of 0 to 9 (or corresponding Access Identity 0), 12 to 14 (or corresponding Access Identity) or to Access Identity 1, 2 or 3 shall behave as if the cell status is "barred" in case the cell is "reserved for operator use" for the registered PLMN or the selected PLMN.

[0338] NOTE 3: ACs 11, 15 (or corresponding Access Identity) are only valid for use in the HPLMN / EHPLMN; ACs 12, 13, 14 (or corresponding Access Identity) are only valid for use in the home country TS 22.011 [4].

[0339] NOTE 4: Access Identities 1, 2 are valid in the PLMNs as specified in TS 22.261

[0041] .

[0340] NOTE 5: Access Identity 3 is only valid for PLMNs that indicate to potential Disaster Inbound Roamers that the UEs can access the PLMN as specified in TS 22.261

[0041] .

[0341] When cell status "barred" is indicated or to be treated as if the cell status is "barred",

[0342] - The UE is not permitted to select / reselect this cell, not even for emergency calls.

[0343] - The UE shall consider other cells for cell selection / reselection according to the following rule:

[0344] - If the cell is to be treated as if the cell status is "barred" due to the cell being an S&F cell and a non-S&F cell is detected, or;

[0345] - If the cell is to be treated as if the cell status is "barred" due to being unable to acquire theMasterInformationBlock (orMasterInformationBlock-NB),theSystemInformationBlockType1 (orSystemInformationBlockType1-BRmessage orSystemInformationBlockType1-NB),theSystemInformationBlockType2 (orSystemInformationBlockType2-NB)orSystemInformationBlockType31 (orSystemInformationBlockType31-NB)if broadcasted for UEs supporting NTN:

[0346] - - the UE may exclude the barred cell as a candidate for cell selection / reselection for up to 300 seconds.

[0347] - - the UE may select another cell on the same frequency if the selection criteria are fulfilled.

[0348] - - the UE may select the same cell in normal coverage if the UE was barred in the cell due to being unable to acquireMasterInformationBlock,SystemInformationBlockType1-BR, orSystemInformationBlockType2in enhanced coverage, but was able to acquireMasterInformationBlock,SystemInformationBlockType1, andSystemInformationBlockType2in normal coverage, if the selection criteria are fulfilled.

[0349] - - the UE may select the same cell in enhanced coverage if the UE was barred in the cell due to being unable to acquireMasterInformationBlock,SystemInformationBlockType1, orSystemInformationBlockType2in normal coverage, but was able to acquireMasterInformationBlock,SystemInformationBlockType1-BR, andSystemInformationBlockType2, if the selection criteria are fulfilled.

[0350] - else

[0351] - - If the cell is a CSG cell:

[0352] - - - the UE may select another cell on the same frequency if the selection / reselection criteria are fulfilled.

[0353] - - else

[0354] - - - If the fieldintraFreqReselectionin fieldcellAccessRelatedInfoinSystemInformationBlockType1 (orSystemInformationBlockType1-BRmessage orSystemInformationBlockType1-NB)message is set to "allowed", the UE may select another cell on the same frequency if re-selection criteria are fulfilled.

[0355] - - - - The UE shall exclude the barred cell as a candidate for cell selection / reselection for 300 seconds.

[0356] - - - If the fieldintraFreqReselectionin fieldcellAccessRelatedInfoinSystemInformationBlockType1(orSystemInformationBlockType1-BRmessage orSystemInformationBlockType1-NB) message is set to "not allowed" the UE shall not re-select a cell on the same frequency as the barred cell;

[0357] - - - - The UE shall exclude the barred cell and the cells on the same frequency as a candidate for cell selection / reselection for 300 seconds.

[0358] The cell selection of another cell may also include a change of RAT or, if the previous and selected cell are both E-UTRA cells, a change of the CN type.

[0359] ----------------- 36.304 Example -----------------

[0360] Example C

[0361] ----------------- 36.331 Example -----------------

[0362]

[0363]

[0364] ----------------- 36.331 Example -----------------

[0365] Example D

[0366] ----------------- 36.304 Example -----------------

[0367] 5.2.4.1 Reselection priorities handling

[0368] Absolute priorities of different E-UTRAN frequencies or inter-RAT frequencies may be provided to the UE in the system information, in theRRCConnectionReleaseorRRCEarlyDataCompletemessage, or by inheriting from another RAT at inter-RAT cell (re)selection. In the case of system information, an E-UTRAN frequency or inter-RAT frequency may be listed without providing a priority (i.e. the fieldcellReselectionPriorityis absent for that frequency). If priorities are provided in dedicated signalling, the UE shall ignore all the priorities provided in system information. If UE is incamped on any cellstate, UE shall only apply the priorities (i.e.cellReselectionPriorityand / orcellReselectionSubPriority) provided by system information from current cell, and the UE preserves priorities provided by dedicated signalling,deprioritisationReqreceived inRRCConnectionRejectandaltFreqPrioritiesprovided by dedicated signalling unless specified otherwise. When the UE incamped normallystate, has only dedicated priorities other than for the current frequency, the UE shall consider the current frequency to be the lowest priority frequency (i.e. lower than any of the network configured values). While the UE is camped on a suitable CSG cell in normal coverage, the UE shall always consider the current frequency to be the highest priority frequency (i.e. higher than any of the network configured values), irrespective of any other priority value allocated to this frequency. When the HSDN capable UE is in High-mobility state, the UE shall always consider the HSDN cells to be the highest priority (i.e. higher than any other network configured priorities). When the HSDN capable UE is not in High-mobility state, the UE shall always consider HSDN cells to be the lowest priority (i.e. lower than network configured priorities). If the UE capable of sidelink communication is configured to perform sidelink communication and can only perform the sidelink communication while camping on a frequency, the UE may consider that frequency to be the highest priority. If the UE capable of V2X sidelink communication is configured to perform V2X sidelink communication and can only perform the V2X sidelink communication while camping on a frequency, the UE may consider that frequency to be the highest priority. If the UE capable of V2X sidelink communication is configured to perform V2X sidelink communication and can only use pre-configuration while not camping on a frequency, the UE may consider the frequency providing inter-carrier V2X sidelink configuration to be the highest priority. If the UE is configured to perform both V2X sidelink communication and NR sidelink communication, the UE may consider the frequency providing both V2X sidelink communication and NR sidelink communication configuration to be the highest priority.If the UE is configured to perform V2X sidelink communication and not perform NR sidelink communication, the UE may consider the frequency providing V2X sidelink communication configuration to be the highest priority. If the UE is configured to perform NR sidelink communication and not perform V2X sidelink communication, the UE may consider the frequency providing NR sidelink communication configuration to be the highest priority. If the UE capable of sidelink discovery is configured to perform Public Safety related sidelink discovery and can only perform the Public Safety related sidelink discovery while camping on a frequency, the UE may consider that frequency to be the highest priority. A UE on a vehicle with an NR mobile-IAB cell detected may consider the inter-RAT frequency for which an NR mobile-IAB cell is the best cell to be the highest priority. The UE identifies an NR mobile-IAB cell bymobileIAB-Cellin SIB1 (see TS 38.331

[0037] ). The UE may narrow its search scope for NR mobile-IAB cell(s) bymobileIAB-CellListif broadcasted inSystemInformationBlockType24(see TS 36.331 [3]). A non-mobile-IAB cell may be excluded from this mobile IAB frequency prioritization for up to 300 seconds.

[0369] A UE capable of S&F shall consider S&F cells to be of the lowest priority if the UE is able to detect other non-S&F cells on the same frequency, on inter-frequencies or inter-RAT frequencies.

[0370] NOTE 1: The prioritization among the frequencies which UE considers to be the highest priority frequency is left to UE implementation.

[0371] NOTE 1a: The frequency only providing the anchor frequency configuration should not be prioritized for V2X service during cell reselection as specified in TS 36.331[3].

[0372] NOTE 1b: When UE　is configured to perform NR sidelink communication or V2X sidelink communication performs cell reselection,　it may consider　the frequencies providing the intra-carrier and inter-carrier configuration　have equal priority　in cell reselection.

[0373] NOTE 1c: The UE is configured to perform V2X sidelink communication or NR sidelink communication, if it has the capability and is authorized for the corresponding sidelink operation.

[0374] NOTE 1d: When UE is configured to perform both NR sidelink communication and V2X sidelink communication, but cannot find a frequency which can provide both NR sidelink communication configuration and V2X sidelink communication configuration, UE may consider the frequency providing either NR sidelink communication configuration or V2X sidelink communication configuration to be the highest priority.

[0375] NOTE 1e: How the UE determines itself to be on a vehicle with an NR mobile-IAB cell is left to UE implementation.

[0376] ----------------- 36.304 Example -----------------

[0377] Example E

[0378] ----------------- 36.304 Example -----------------

[0379] 4 General description of Idle mode

[0380] 4.1 Overview

[0381] ... OMITTED ...

[0382] IfSystemInformationBlockType32has been received and if the UE has determined that it is out of coverage using available satellite assistance information (e.g. ephemeris parameters and coverage parameters in current or previously receivedSystemInformationBlockType32,SystemInformationBlockType31,t-ServiceinSystemInformationBlockType3or other parameters), the AS configuration (e.g. priorities provided by dedicated signalling and logged measurements) is kept, but the UE need not perform any idle mode tasks related to NTN. It is up to UE implementation to handle running timers. The detection of out of coverage using satellite assistance information is up to UE implementation and once in NTN coverage the UE shall perform all idle mode tasks related to NTN. IfSystemInformationBlockType32includescarrierFreqListthe UE may store and use this information for the cell selection process when UE resumes the idle mode tasks related to NTN once in NTN coverage. A UE supporting S&F shall apply the S&F assistance information (for instance viasAndF-SatelliteInfoListinSystemInformationBlockType32and / or a list of satelliteIds from upper layers) to determine whether UE is out-of-coverage.

[0383] ----------------- 36.304 Example -----------------

[0384] Example F

[0385] ----------------- 36.304 Example -----------------

[0386] -SystemInformationBlockType32

[0387] The IESystemInformationBlockType32contains satellite assistance information for prediction of discontinuous coverage.SystemInformationBlockType32is only signalled in a NTN cell.

[0388]

[0389]

[0390] ----------------- 36.304 Example -----------------

[0391] Figure 8 is a block diagram of an exemplary network entity / function that may be used in examples of the present disclosure, such as the techniques disclosed in relation to any of the preceding figures. For example, any of the network entities, network function etc. (e.g. UE, BS, gNB / eNB, ATG entities) may be provided in the form of the network entity illustrated in Figure 8. The skilled person will appreciate that a network entity / function may be implemented, for example, as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, and / or as a virtualised function instantiated on an appropriate platform, e.g. on a cloud infrastructure.

[0392] The entity 800 comprises a processor (or controller) 801, a transmitter 803 and a receiver 805. The receiver 805 is configured for receiving one or more messages from one or more other network entities, for example as described above. The transmitter 803 is configured for transmitting one or more messages to one or more other network entities, for example as described above. The processor 801 is configured for performing one or more operations, for example according to the operations as described above.

[0393] Figure 9 provides a diagram illustrating an method performed by a UE in an embodiment of the disclosure.

[0394] In operation 910, the UE may receive indication information of one or more satellites providing one or more NTN S&F cells.

[0395] In an embodiment of the disclosure, the UE may receive, from the network, a non-access stratum (NAS) message comprising the indication information of the one or more satellites. In an embodiment of the disclosure, the NAS message may be received from a mobility management entity (MME) of the network. In an embodiment of the disclosure, the indication information of the one or more satellites may comprise a list of one or more satellite identifiers (IDs).

[0396] In operation 920, the UE may receive, from a network, satellite assistance information on at least one satellite. In an embodiment of the disclosure, the satellite assistance information may be received in system information from the network. In an embodiment of the disclosure, the satellite assistance information may comprise ephemeris information and service start time information.

[0397] In an embodiment of the disclosure, the UE may determine a coverage of the one or more satellites based on the satellite assistance information.

[0398] In operation 930, the UE may perform an idle mode operation based on the received satellite assistance information. In an embodiment of the disclosure, the idle mode operation may comprise performing measurement for cell selection in an idle mode.

[0399] In an embodiment of the disclosure, the UE may perform the idle mode operation in coverage of the one or more satellites. In an embodiment of the disclosure, the idle mode operation may be not performed outside coverage of the one or more satellite.

[0400] In an embodiment of the disclosure, the UE may enter a power saving mode outside coverage of the one or more satellites. In an embodiment of the disclosure, the UE may wake up from the power saving mode in coverage of the one or more satellites.

[0401] In an embodiment of the disclosure, the UE may transmit, to the network, indication information of the at least one satellite on which the UE lacks satellite assistance information. In an embodiment of the disclosure, the indication information of the at least one satellite on which the UE lacks satellite assistance information may be sent via a radio resource control (RRC) message.

[0402] In an embodiment of the disclosure, the UE may receive, from the network, a request to identify whether the UE lacks the satellite assistance information on the at least one satellite. In an embodiment of the disclosure, the UE may identify whether the UE lacks the satellite assistance information on the at least one satellite.

[0403] The present disclosure provides approaches for RRC idle and RRC inactive mode operation in Store and Forward networks.

[0404] In accordance with an aspect of the present disclosure, there is provided a method of a user equipment (UE) for operating in a wireless communications network, the wireless communications network including one or more non-terrestrial network (NTN) store and forward (S&F) cells, the method comprising: receiving an indication of one or more satellites providing the NTN S&F cells; receiving, from the network, satellite assistance information on the one or more of the indicated satellites; and performing an idle mode operation based on the received satellite assistance information.

[0405] In an example, performing an idle mode operation based on the received satellite assistance information includes performing an idle mode operation when in coverage of the one or more satellites providing the NTN S&F cells.

[0406] In an example, performing an idle mode operation based on the received satellite assistance information includes not performing an idle mode operation when not in coverage of the one or more satellite providing the NTN S&F cells.

[0407] In an example, the UE enters a reduced power mode (e.g. a sleep mode or a discontinuous coverage mode) outside coverage of the one or more satellites providing the NTN S&F cells.

[0408] In an example, the UE wakes up from a reduced power mode when in coverage of the one or more satellite providing the NTN S&F cells.

[0409] In an example, the receiving an indication of one or more satellites providing the NTN S&F cells includes receiving a non-access stratum (NAS) message from the network including an indication of the one or more satellites providing the NTN S&F cells.

[0410] In an example, the NAS message is received from a mobility management entity (MME) of the network.

[0411] In an example, the satellite assistance information is received in broadcast information from the network.

[0412] In an example, the satellite assistance information is received in system information broadcast by the network.

[0413] In an example, the satellite assistance information includes ephemeris information and service start time information.

[0414] In an example, the method further includes determining a coverage of the one or more NTN S&F cells based on the satellite assistance information.

[0415] In an example, the satellite assistance information is received from an S&F eNB.

[0416] In an example, the receiving, from the network, satellite assistance information on the one or more of the indicated satellites includes receiving satellite assistance information for the indicated satellites the UE lacks satellite assistance information on.

[0417] In an example, the method further comprises transmitting, to the network, an indication of the satellite(s) the UE lacks satellite assistance information on.

[0418] In an example, the indication of the satellite(s) the UE lacks satellite assistance information on includes satellite ID(s) of the satellite(s) the UE lacks satellite assistance information on.

[0419] In an example, the indication of the satellite(s) the UE lacks satellite assistance information on is sent via a radio resource control (RRC) message.

[0420] In an example, the method further comprises: receiving, from the network, a request to check if the UE lacks satellite assistance information on the one or more satellites providing the NTN S&F cells; checking if the UE lacks satellite assistance information on the one or more satellites providing the NTN S&F cells; and if the UE lacks satellite assistance information on the one or more satellites providing the NTN S&F cells, transmitting, to the network, the indication of the satellites the UE lacks satellite assistance information on.

[0421] In an example, the indication of one or more satellites providing the NTN S&F cells includes a list of one or more satellite IDs.

[0422] In an example, the UE is a Internet of Things (IoT) device.

[0423] In an example, the idle mode operation includes performing measurements on an NTN cell for cell selection.

[0424] In accordance with a second aspect of the present disclosure, there is provided a user equipment (UE) for operating in a wireless communications network, the wireless communications network including one or more non-terrestrial network (NTN) store and forward (S&F) cells, wherein the UE is configured to perform the method of any preceding claim.

[0425] It will be appreciated that, in each example / embodiment / aspect etc. described above, one or more features or operations may be omitted, modified or moved (e.g., to change the order of the features or the operations), if desired and appropriate.

[0426] Additionally, where the figures illustrating example method flows include text in relation to a specific step / operation, it will be appreciated that this text is simply an example of the corresponding step / operation, where a more general definition (such as may be found in the description of the corresponding step) may apply for the step / operation.

[0427] Additionally, regarding all of the above, one or more features or operations etc. from any example / embodiment may be combined with features or operations from any other example / embodiment. That is, the present disclosure should be considered to include all combinations of examples / embodiments disclosed herein, as appropriate, as well as combinations of individual features within and between each example / embodiment, as appropriate.

[0428] The techniques described herein may be implemented using any suitably configured apparatus and / or system. Such an apparatus and / or system may be configured to perform a method according to any aspect, embodiment or example disclosed herein. Such an apparatus may comprise one or more elements, for example one or more of receivers, transmitters, transceivers, processors, controllers, modules, units, and the like, each element configured to perform one or more corresponding processes, operations and / or method steps for implementing the techniques described herein. For example, an operation / function of X may be performed by a module configured to perform X (or an X-module). The one or more elements may be implemented in the form of hardware, software, or any combination of hardware and software.

[0429] It will be appreciated that examples of the present disclosure may be implemented in the form of hardware, software or any combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile storage, for example a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape or the like.

[0430] It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs comprising instructions that, when executed, implement certain examples of the present disclosure. Accordingly, certain examples provide a program comprising code for implementing a method, apparatus or system according to any example, embodiment and / or aspect disclosed herein, and / or a machine-readable storage storing such a program. Still further, such programs may be conveyed electronically via any medium, for example a communication signal carried over a wired or wireless connection.

[0431] While the disclosure has been shown and described with reference to certain examples, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the disclosure.

[0432] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0433] Further examples in accordance with the present disclosure are set out in the following first set of numbered clauses, where these may be combined with any of the other examples, implementations, and clauses of this disclosure.

[0434] 1. A method of a user equipment (UE) for operating in a wireless communications network, the wireless communications network including one or more non-terrestrial network (NTN) store and forward (S&F) cells and one or more non-S&F cells, the method comprising:

[0435] detecting one or more cells; and

[0436] if an S&F cell and a non-S&F cell are detected, adjusting a selection priority of the detected S&F cell relative to the non-S&F cell, and performing cell selection based on the adjusted selection priority.

[0437] 2. The method of clause 1, wherein adjusting a selection priority of the detected S&F cell relative to the non-S&F cell includes barring the S&F cell from being selected if the S&F cell is indicated by the network as being barred.

[0438] 3. The method of clauses 1 or 2, wherein adjusting a selection priority of the detected S&F cell relative to the non-S&F cell includes barring the S&F cell from being selected if the detected S&F cell and non-S&F cell are within same a same frequency, within a same radio access technology (RAT), and / or with a same public land mobile network (PLMN).

[0439] 4. The method of any of clauses 1 to 3, wherein adjusting a selection priority of the detected S&F cell relative to the non-S&F cell includes barring the S&F cell from being selected if the non-S&F cell is a suitable cell.

[0440] 5. The method of clause 1, wherein adjusting a selection priority of the detected S&F cell relative to the non-S&F cell includes reducing the selection priority of the S&F cell.

[0441] 6. The method of clause 5, wherein reducing the selection priority includes reducing the S&F cell to a lowest selection priority.

[0442] 7. The method of any preceding clause, wherein the adjusting a selection priority of the detected S&F cell relative to the non-S&F is based on one or more characteristics of the non-S&F cell.

[0443] 8. The method of any preceding clause, wherein the adjusting a selection priority of the detected S&F cell relative to the non-S&F is based on a UE and / or a network configuration.

[0444] 9. The method of any preceding clause, wherein the adjusting a selection priority of the detected S&F cell relative to the non-S&F is based on an indicator received from the S&F cell and / or a configuration received from the network.

[0445] 10. The method of any preceding clause, wherein, if the non-S&F is barred, selecting the S&F cell (i.e. adjusting the S&F cell to have a higher priority than the non-S&F cell).

[0446] 11. The method of any preceding clause, wherein, if an S&F cell is detected and a non-S&F cell is not detected, performing cell selection based on the detected S&F cell.

[0447] 12. A user equipment (UE) for operating in a wireless communications network, the wireless communications network including one or more non-terrestrial network (NTN) store and forward (S&F) cells and one or more non-S&F cells, wherein the UE is configured to perform the method of any preceding clause.

[0448] Further examples in accordance with the present disclosure are set out in the following second set of numbered clauses, where these may be combined with any of the other examples, implementations, and clauses of this disclosure.

[0449] 1. A method of a user equipment (UE) for operating in a wireless communications network, the wireless communications network including a plurality of non-terrestrial network (NTN) cells provided by a respective plurality of satellites, and wherein each of the NTN cells provides discontinuous coverage to the UE, the method comprising:

[0450] performing an idle mode task within the coverage of only a subset of the plurality of satellites.

[0451] 2. The method of clause 1, further comprising, receiving from the network, an indication of the subset of satellites.

[0452] 3. The method of clause 2, wherein the indication includes an identifier (e.g. satellite ID) of each satellite of the subset of satellites.

[0453] 4. The method of clauses 2 or 3, wherein the indication provides an indication of the satellites not included in the subset of satellites.

[0454] 5. The method of any of clauses 2 to 4, wherein the indication includes a list indicating satellites of the plurality of satellites included in the subset and / or a list indicating satellites of the plurality of satellites not included in the subset.

[0455] 6. The method of any of clauses 2 to 5, wherein the indication of the subset of satellites is received through higher layer messaging (e.g. a NAS message).

[0456] 7. The method of any preceding clause, wherein the method further comprises receiving coverage-related information on the subset of satellites from the network.

[0457] 8. The method of clause 7, wherein the coverage-related information is received through broadcast information from the network.

[0458] 9. The method of clause 8, wherein the method further comprises determining the coverage timings of the subset of satellites based on the coverage-related information, and performing the idle mode task based on the determined coverage timings.

[0459] 10. The method of any preceding clause, wherein at least one satellite of the satellites not included in the subset is a Store and Forward (S&F) satellite.

[0460] 11. The method of any preceding clause, wherein all the satellites from the plurality of satellites not included in the subset are S&F satellites.

[0461] 12. The method of any preceding clause, wherein all the satellites from the subset are non- S&F satellites.

[0462] 13. The method of any preceding clause, wherein the idle mode task includes one or more NTN idle mode tasks.

[0463] 14. The method of any preceding clause, wherein the UE enters a reduced power mode (i.e. is in a sleep mode, in a discontinuous coverage mode, on deemed to be in discontinuous coverage ) outside of the coverage of the subset of satellites.

[0464] 15. A user equipment (UE) for operating in a wireless communications network, the wireless communications network including a plurality of non-terrestrial network (NTN) cells provided by a respective plurality of satellites, and wherein each of the NTN cells provides discontinuous coverage to the UE, wherein the UE is configured to perform the method of any preceding clause.

[0465] Further examples in accordance with the present disclosure are set out in the following third set of numbered clauses, where these may be combined with any of the other examples, implementations, and clauses of this disclosure.

[0466] 1. A method of a user equipment (UE) for operating in a wireless communications network, the wireless communications network including one or more non-terrestrial network (NTN) store and forward (S&F) cells providing discontinuous coverage, the method comprising:

[0467] receiving an indication of one or more satellites providing the NTN cells;

[0468] if the UE lacks sufficient satellite assistance information on one or more of the indicated satellites, receiving from the network the satellite assistance information on the one or more of the indicated satellites the UE lacks; and

[0469] performing an idle mode and / or an inactive mode operation based on the received satellite assistance information.

[0470] 2. The method of clause 1, wherein the receiving an indication of one or more satellites providing the NTN cells includes receiving a non-access stratum (NAS) message from the network including an indication of the one or more satellites providing the NTN cells.

[0471] 3. The method of clause 2, wherein the NAS message is received from a mobility management entity (MME) of the network.

[0472] 4. The method of any preceding clause, wherein the one or more satellites providing the NTN cells includes at least one S&F satellite.

[0473] 5. The method of any preceding clause, wherein the method further includes receiving initial satellite assistance information on at least one satellite of the indicated satellites from the network prior to receiving the indication of one or more satellites providing the NTN cells.

[0474] 6. The method of clause 5, wherein the initial satellite assistance information is received in broadcast information from the network.

[0475] 7. The method of clauses 5 or 6, wherein the initial satellite assistance information includes an indication of whether the at least one satellite is an S&F satellite.

[0476] 8. The method of any preceding clause, wherein the receiving satellite assistance information on the one or more of the indicated satellites on which the UE lacks sufficient information includes receiving satellite assistance information that was not include in the initial satellite assistance information.

[0477] 9. The method of any preceding clause, wherein the satellite assistance information on the one or more of the indicated satellites that the UE lacks is received from an S&F eNB.

[0478] 10. The method of any preceding clause, wherein the indication of one or more satellites providing the NTN cells includes an indication of one or more satellite IDs.

[0479] 11. The method of any preceding clause, wherein the method further includes, indicating by the UE to the network, the satellite assistance information the UE lacks on the one or more of the indicated satellites.

[0480] 12. The method of any preceding clause, wherein the method further includes determining, by the UE, whether the UE lacks satellite assistance information on the one or more of the indicated satellites.

[0481] 13. The method of clause 12, wherein the determining, by the UE, whether the UE lacks information on one or more of the indicated satellites, is performed in response to a polling request receiving from the network.

[0482] 14. The method of any of clauses 1 to 10, wherein the satellite assistance information on the one or more of the indicated satellites that the UE lacks is identified by the network.

[0483] 15. A user equipment (UE) for operating in a wireless communications network, the wireless communications network including one or more non-terrestrial network (NTN) store and forward (S&F) cells, wherein the UE is configured to perform the method of any preceding clause.

[0484] 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.

[0485] Acronyms and Definitions

[0486] 3GPP 3rdGeneration Partnership Project

[0487] 5G 5thGeneration

[0488] 5GC 5G Core

[0489] 5QI 5G QoS Identifier

[0490] 5GS 5G System

[0491] 5GSM 5G System Session Management

[0492] 5GMM 5G System Mobility Management

[0493] AF Application Function

[0494] AI Artificial Intelligence

[0495] AM Acknowledged Mode

[0496] AMF Access and Mobility Management Function

[0497] AS Access Stratum

[0498] ASP Application Service Provider

[0499] ATG Air-To-Ground

[0500] AUSF Authentication Server Function

[0501] CDN Content Delivery Network

[0502] DCAF Data Collection Application Function

[0503] DNAI Data Network Access Identifier

[0504] DNN Data Network Name

[0505] DNS Domain Name Server

[0506] DRB Data Radio Bearer

[0507] eNB Evolved Node B

[0508] EPC Evolved Packet Core

[0509] E-UTRA Evolved Universal Terrestrial Radio Access

[0510] FEC Forward Error Correction

[0511] FQDN Fully Qualified Domain Name

[0512] GBR Guaranteed Bit Rate

[0513] gNB Next generation Node B

[0514] GPSI Generic Public Subscription Identifier

[0515] HSS Home Subscriber Service

[0516] IAB Integrated Access and Backhaul

[0517] ID Identity / Identifier

[0518] IoT Internet of Things

[0519] IIoT Industrial Internet of Things

[0520] IMEI International Mobile Equipment Identities

[0521] IP Internet Protocol

[0522] I-SMF Intermediate SMF

[0523] LADN Local Area Data Network

[0524] LL SSM Lower Layer SSM

[0525] LTE Long Term Evolution

[0526] LTE-M LTE-Machine

[0527] MBMS Multimedia Broadcast / Multicast Service

[0528] MBS Multicast / Broadcast Service

[0529] MBSF Multicast / Broadcast Service Function

[0530] MBSTF Multicast / Broadcast Service Transport Function

[0531] MB-SMF Multicast / Broadcast Session Management Function

[0532] MB-UPF Multicast / Broadcast User Plane Function

[0533] MIB Master Information Block

[0534] ML Machine Learning

[0535] MME Mobility Management Entity

[0536] MN Master Node

[0537] MNF Monitoring Network Function

[0538] MNO Mobile Network Operator

[0539] MT Mobile Termination

[0540] NAS Non-Access Stratum

[0541] NB-IoT Narrow Band Internet of Things

[0542] NEF Network Exposure Function

[0543] NR New Radio

[0544] NRF Network Repository Function

[0545] NG-RAN Next Generation Radio Access Network

[0546] NG-eNB Next Generation eNB

[0547] NSA Non-Standalone

[0548] NSSF Network Slice Selection Function

[0549] NTN Non-Terrestrial Networks

[0550] NW Network

[0551] NWDAF Network Data Analytics Function

[0552] OS Operating System

[0553] OSAPP OS Application

[0554] PCF Policy Control Function

[0555] PCO Protocol Configuration Options

[0556] PDR Packet Detection Rule

[0557] PDU Protocol Data Unit

[0558] PLMN Public Land Mobile Network

[0559] PTM Point To Multipoint

[0560] PTP Point to Point

[0561] QFI QoS Flow Identifier (ID)

[0562] QoS Quality of Service

[0563] RACH Random Access Channel

[0564] RAN Radio Access Network

[0565] RAT Radio Access Technology

[0566] RRC Radio Resource Control

[0567] RSD Route Selection Descriptor

[0568] SA Standalone

[0569] SDAP Service Data Adaptation Protocol

[0570] SDU Service Data Unit

[0571] S&F Store and Forward

[0572] SGW Serving Gateway

[0573] SIB System Information Block

[0574] SIM Subscriber Identity Module

[0575] SLA Service Level Agreement

[0576] SM Session Management

[0577] SMF Session Management Function

[0578] SN Secondary Node

[0579] S-NSSAI Single Network Slice Selection Assistance Information

[0580] SSB Synchronization Signal Block

[0581] SSM Source Specific IP Multicast address

[0582] SSC Session and Service Continuity

[0583] SRB Signaling Radio Bearer

[0584] SUPI Subscription Permanent Identifier

[0585] TA Tracking Area

[0586] TAI Tracking Area Identity

[0587] TE Terminal Equipment

[0588] TM Transparent Mode

[0589] TMGI Temporary Mobile Group Identity

[0590] TN Terrestrial Network

[0591] TS Technical Specification

[0592] UAV Unmanned Aerial Vehicle

[0593] UDM Unified Data Manager

[0594] UDR Unified Data Repository

[0595] UE User Equipment

[0596] UL Uplink

[0597] UM Unacknowledged Mode

[0598] UP User Plane

[0599] UPF User Plane Function

[0600] URLLC Ultra-Reliable and Low-Latency Communication

[0601] URSP UE Route Selection Policy

Claims

1.A method performed by a user equipment (UE) in a wireless communication system, the method comprising:receiving indication information of one or more satellites providing one or more non-terrestrial network (NTN) store and forward (S&F) cells;receiving, from a network, satellite assistance information on at least one satellite; andperforming an idle mode operation based on the received satellite assistance information.2.The method of claim 1, wherein the performing of the idle mode operation comprises performing the idle mode operation in coverage of the one or more satellites.3.The method of claim 1, wherein the idle mode operation is not performed outside coverage of the one or more satellite.4.The method of claim 1, further comprising:entering a power saving mode outside coverage of the one or more satellites; andwaking up from the power saving mode in coverage of the one or more satellites.5.The method of claim 1, wherein the receiving of the indication information of the one or more satellites comprises receiving, from the network, a non-access stratum (NAS) message comprising the indication information of the one or more satellites.6.The method of claim 5, wherein the NAS message is received from a mobility management entity (MME) of the network.7.The method of claim 1, wherein the satellite assistance information is received in system information from the network.8.The method of claim 1, wherein the satellite assistance information comprises ephemeris information and service start time information.9.The method of claim 1, further comprising:determining a coverage of the one or more satellites based on the satellite assistance information.10.The method of claim 1, further comprising:transmitting, to the network, indication information of the at least one satellite on which the UE lacks satellite assistance information.11.The method of claim 10, wherein the indication information of the at least one satellite on which the UE lacks satellite assistance information is sent via a radio resource control (RRC) message.12.The method of any of claim 1, further comprising:receiving, from the network, a request to identify whether the UE lacks the satellite assistance information on the at least one satellite; andidentifying whether the UE lacks the satellite assistance information on the at least one satellite.13.The method of claim 1, wherein the indication information of the one or more satellites comprises a list of one or more satellite identifiers (IDs).14.The method of claim 1, wherein the idle mode operation comprises performing measurement for cell selection in an idle mode.15.A user equipment (UE) in a wireless communication system, the UE comprising:a transceiver; andat least one processor configured to:receive indication information of one or more satellites providing one or more non-terrestrial network (NTN) store and forward (S&F) cells;receive, from a network, satellite assistance information on at least one satellite; andperform an idle mode operation based on the received satellite assistance information.

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