Storing and forwarding method and device in NTN deployment

Abstract

The present disclosure relates to a 5G or 6G communication system supporting a higher data transmission rate. The system includes a first entity in a non-terrestrial network (NTN), the first entity configured to operate in a store-and-forward (Samp; F) mode based on its inclusion in a satellite providing discontinuous coverage, where the first entity is configured to transmit to a second entity regarding the Samp; and F mode information.

Description

Technical Field

[0001] Certain examples of the present disclosure relate to methods, apparatuses, and / or systems for supporting store-and-forward-based procedures in NTN deployments. Furthermore, certain examples of the present disclosure relate to methods and apparatus for supporting store-and-forward-based procedures in NTNs with discontinuous coverage by locating the RAN in a network entity such as a satellite or HAPS. Furthermore, certain examples of the present disclosure relate to restricting and / or enabling certain network procedures for UEs based on an eNB-based store-and-forward mode. Furthermore, certain examples of the present disclosure delay or advance one or more portions of a recovery procedure in a store-and-forward network. Background Art

[0002] 5G mobile communications technology defines a wide frequency band, enabling high transmission rates and new services. This technology can be implemented not only in "sub-6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands, known as millimeter waves, including 28 GHz and 39 GHz. Furthermore, to achieve transmission rates 50 times faster than 5G mobile communications technology and ultra-low latency as low as one-tenth that of 5G mobile communications technology, 6G mobile communications technology is also being considered in the terahertz frequency band (e.g., the 95 GHz to 3 THz band) (referred to as "beyond 5G systems").

[0003] In the early stages of 5G mobile communication technology development, in order to support services and meet the performance requirements associated with enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC) and massive machine-type communications (mMTC), ongoing standardization work involves technologies such as beamforming and massive MIMO technologies for reducing radio wave path loss and increasing radio wave transmission distance in millimeter waves, parameter set support technologies for dynamic operation of millimeter wave resources and time slot formats (for example, operating with multiple subcarrier spacings), initial access technologies supporting multi-beam transmission and broadband, definition and operation of BWP (bandwidth part), new channel coding methods such as LDPC (low-density parity-check) codes for large-scale data transmission and polar codes for highly reliable control information transmission, L2 preprocessing technologies, and network slicing technologies that provide dedicated networks for specific services.

[0004] Currently, discussions are underway to improve and enhance the performance of the initial 5G mobile communication technology, taking into account the services it will support. Furthermore, physical layer standardization work is already underway involving technologies such as: V2X (Vehicle-to-Everything) technology, which aims to assist autonomous vehicles in making driving decisions and improve user convenience based on the location and status information transmitted by vehicles; New Radio (NR-U) technology in unlicensed frequency bands, which aims to enable system operation in unlicensed frequency bands that meets various regulatory requirements; NR UE energy-saving technology; Non-Terrestrial Network (NTN) technology, which enables direct communication between UEs and satellites to provide coverage in areas where communication with terrestrial networks is impossible; and positioning technology.

[0005] In addition, in terms of air interface architecture / protocols, ongoing standardization work involves technologies such as: Industrial Internet of Things (IIoT) technologies that support new services through interoperability and integration with other industries; IAB (Integrated Access and Backhaul) technologies that provide nodes for network service area expansion by integrating wireless backhaul links and access links; mobility enhancement technologies (including conditional handover and DAPS (Dual Active Protocol Stack) handover) to improve the performance of UE handover between different network nodes; and two-step random access (NR's 2-step RACH) technology to simplify the random access process. In terms of system architecture / services, ongoing standardization work involves technologies such as: 5G baseline architecture (e.g., service-based architecture or service-based interface) that combines network function virtualization (NFV) and software-defined networking (SDN) technologies; and mobile edge computing (MEC) technologies for receiving services based on UE location.

[0006] With the commercialization of 5G mobile communication systems, an exponentially increasing number of connected devices will be connected to communication networks. Therefore, it is expected that enhancing the functionality and performance of 5G mobile communication systems and enabling the integrated operation of connected devices will become essential. To this end, new research is planned in areas such as extended reality (XR) to efficiently support AR (augmented reality), VR (virtual reality), and MR (mixed reality); leveraging artificial intelligence (AI) and machine learning (ML) to enhance 5G performance and reduce complexity; supporting AI services, supporting metaverse services, and drone communications.

[0007] In addition, these developments in 5G mobile communication systems will not only lay the foundation for the development of the following technologies: new waveforms for providing coverage in the terahertz band of 6G mobile communication technology; multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO), array antennas, and massive antennas; metamaterial-based lenses and antennas for improving signal coverage in the terahertz band; high-dimensional spatial multiplexing technology using OAM (orbital angular momentum) and RIS (reconfigurable smart surface) technology; but will also lay the foundation for the development of the following technologies: full-duplex technology for improving the frequency efficiency of 6G mobile communication technology and improving system networks; AI-based communication technology that achieves system optimization by leveraging satellites and AI from the design stage and integrating end-to-end AI support functions; and next-generation distributed computing technology that uses ultra-high-performance communication and computing resources to implement services with complexity that exceeds the operational capabilities of UEs.

[0008] Fifth-generation (5G) or New Radio (NR) mobile communications has been rapidly developing recently, driven by global industry and academia's technical activities on various candidate technologies. Candidate driving technologies for 5G / NR mobile communications include massive antenna technology (moving from traditional cellular bands to high-frequency bands to provide beamforming gain and support capacity improvements), new waveforms (e.g., new radio access technologies (RATs) to flexibly accommodate diverse services / applications with different requirements), and new multiple access schemes to support massive connectivity.

[0009] The following documents are referenced below and / or their contents provide background information that should be considered for this disclosure: [1] 3GPP TS 38.331-5G, NR, Radio Resource Control (RRC), Protocol specifications; Version 17 (for example, V17.2.0).

[0010] [2] 3GPP TS 36.331-LTE, Evolved Universal Terrestrial Radio Access (E-UTRA), Radio Resource Control (RRC), Protocol Specification; Release 17 (e.g., V17.2.0).

[0011] (Note: The example versions shown for each TS are not limiting, and other versions of the TS are also contemplated)

[0012] Wireless or mobile (cellular) communication networks, in which mobile terminals (e.g., user equipment (UE), such as mobile phones) communicate with a network of base stations or other wireless access points or nodes via radio links, have undergone rapid development over several generations. The Third Generation Partnership Project (3GPP) designs, develops, and standardizes mobile wireless communication network technologies. Currently, fourth-generation (4G) and fifth-generation (5G) systems are widely deployed.

[0013] The 3GPP standards for 4G systems include the Evolved Packet Core (EPC) and Enhanced Universal Terrestrial Radio Access Network (E-UTRAN). E-UTRAN uses Long Term Evolution (LTE) radio technology. LTE is often used to refer to the entire system, including the EPC and E-UTRAN, and will be used in this context for the remainder of this article. LTE also includes LTE enhancements such as LTE-Advanced and LTE Pro, which offer higher data rates than LTE.

[0014] In 5G systems, a new air interface has been developed, referred to as 5G New Radio (5G NR), or simply NR. NR is designed based on existing LTE technology to support the diverse services and use case scenarios anticipated in 5G networks. As part of 5G networks, new frameworks and architectures are also being developed to expand the range of 5G network capabilities and applicable use cases.

[0015] LTE and 5G NR provide an architecture and framework for non-terrestrial networks (NTNs) and their use. NTNs can include one or more of low-Earth orbit (LEO) satellites, medium-Earth orbit (MEO) satellites, geostationary orbit (GEO) satellites, and high-altitude platform systems (HAPS), or a combination thereof (and / or other non-terrestrial network entities). Therefore, access to the NTN can be achieved through one or more LEO satellites, MEO satellites, GEO satellites, and HAPS.

[0016] Internet of Things (IoT) NTN is a study and work item in 3GPP Release 17, aiming to provide non-terrestrial network access for E-UTRAN IoT devices, such as narrowband (NB)-IoT and Long Term Evolution-Machine Type (LTE-M) / enhanced Machine Type Communication (eMTC). For details, see 3GPP TSG RAN Meeting #90 RP-202689. NR NTN is a work item in Release 17, specifying adaptations that enable NR to operate on NTN. See 3GPP TSG RAN Meeting #91-e RP-211557. Following these work items in Release 17, Release 18 includes work items for enhanced NR NTN (see 3GPP TSG RAN Meeting #95e RP-220953) and IoT NTN (see 3GPP TSG RAN Meeting #95e RP-220979).

[0017] The 17th edition of the IoT NTN work item introduced the concept of discontinuous coverage. Discontinuous coverage refers to scenarios where a satellite network (such as a LEO or MEO satellite network) cannot provide continuous coverage due to insufficient satellite coverage of the entire Earth. This means that coverage may be intermittent as the coverage area moves. For example, if there is only one LEO satellite, depending on the satellite's coverage characteristics, a UE may only have coverage for a few minutes every 24 hours.

[0018] Figure 1a shows a schematic diagram of discontinuous coverage of UE in the case of two satellites, Figure 1b Shown in Figure 1a Example of Reference Signal Received Power (RSRP) measured by a UE over time in the case of

[0019] exist Figure 1a , a first satellite 110 and a second satellite 120 are shown, with paths of the first satellite 110 and the second satellite 120 shown between dashed line 141 and dashed line 143. The first satellite 110 controls a first cell 113, and the second satellite 120 controls a second cell 123. A UE 130 is located on the paths of the satellites 110, 120.

[0020] like Figure 1b As shown, due to the movement of the first satellite 110 and the second satellite 120, the RSRP of the UE 130 (e.g., measured by the UE 130) may vary over time as the UE 130 moves in and out of the coverage of the first cell 113 and the second cell 123. The period of no coverage is represented by the period 150, corresponding to Figure 1b The dashed lines represent the time points when RSRP drops below a certain value (e.g., a threshold), at which point UE 130 is considered to be out of coverage, which may coincide with signal quality degradation or connection loss.

[0021] To save energy when there's no coverage, the UE is allowed to power down and not perform any access stratum functions, such as measurements and cell detection attempts. To ensure the UE knows whether it has coverage, the network sends long-term ephemeris parameters, allowing the UE to predict satellite passes over the next few days. These parameters are sent in the System Information Block (SIB) SIB32. In addition to the ephemeris parameters, the network also sends coverage parameters to inform the UE of the coverage area, allowing the UE to better estimate whether the satellite will provide coverage.

[0022] Since NTN has some specific information elements that are only needed when accessing an NTN cell, and these information elements are large in size, 3GPP believes that a new system information block (SIB) is needed.

[0023] In NR NTN, as defined in TS 38.331 [1], SIB19 contains the information required to access an NTN cell; an excerpt from TS 38.331 [1] is as follows: - SIB19: SIB19 contains satellite assistance information for NTN access.

[0024] SIB19 Information Elements

[0025] --ASN1START

[0026] -- TAG-SIB19-START

[0027] SIB19-r17 ::= SEQUENCE {

[0028] ntn-Config-r17 NTN-Config-r17 OPTIONAL, -- Need R

[0029] t-Service-r17 INTEGER (0..549755813887) OPTIONAL, -- Need R

[0030] referenceLocation-r17 ReferenceLocation-r17 OPTIONAL, -- Need R

[0031] distanceThresh-r17 INTEGER (0..65525) OPTIONAL, -- Need R

[0032] ntn-NeighCellConfigList-r17 NTN-NeighCellConfigList-r17 OPTIONAL, --Need R

[0033] lateNonCriticalExtension OCTET STRING OPTIONAL, ..., [[ ntn-NeighCellConfigListExt-v1720 NTN-NeighCellConfigList-r17 OPTIONAL-Need R ]] } NTN-NeighCellConfigList-r17::= SEQUENCE (SIZE(1..maxCellNTN-r17)) OFNTN-NeighCellConfig-r17 NTN-NeighCellConfig-r17::= SEQUENCE { ntn-Config-r17 NTN-Config-r17 OPTIONAL, -- Need R carrierFreq-r17 ARFCN-ValueNR OPTIONAL, -- Need R physCellId-r17 PhysCellId OPTIONAL -- Need R } -- TAG-SIB19-STOP --ASN1STOP

Table 1

[0034] In IoT NTN, as defined in TS 36.331 [2], SIB31 contains the information required to access an IoT NTN cell; an excerpt from TS 36.331 [2] is as follows: -SystemInformationBlockType31: IE SystemInformationBlockType31 contains the satellite assistance information of the serving cell. SystemInformationBlockType31 is only sent in NTN cells.

[0035] SystemInformationBlockType31 information element

[0036] --ASN1START

[0037] SystemInformationBlockType31-r17 ::= SEQUENCE {

[0038] servingSatelliteInfo-r17 ServingSatelliteInfo-r17, lateNonCriticalExtension OCTET STRING OPTIONAL, ...} ServingSatelliteInfo-r17 ::= SEQUENCE { ephemerisInfo-r17 CHOICE { stateVectors EphemerisStateVectors-r17, orbitalParameters EphemerisOrbitalParameters-r17 }, nta-CommonParameters-17 SEQUENCE { nta-Common-r17 INTEGER (0..8316827) OPTIONAL, -- Need OP nta-CommonDrift-r17 INTEGER (-261935..261935) OPTIONAL, -- Need OP nta-CommonDriftVariation-r17 INTEGER (0..29479) OPTIONAL -- Need OP }, ul-SyncValidityDuration-r17 ENUMERATED {s5, s10, s15, s20, s25, s30,s35, s40, s45, s50, s55, s60, s120, s180, s240, s900}, epochTime-r17 SEQUENCE { startSFN-r17 INTEGER (0..1023), startSubFrame-r17 INTEGER (0..9) }OPTIONAL, -- Need OP k-Offset-r17 INTEGER (0..1023), k-Mac-r17 INTEGER (1..512) OPTIONAL, -- Need OP ... } -- ASN1STOP

Table 2

[0039] According to TS 36.331 [2], the system information SIB31 includes the following: - Serving cell ephemeris element: allows the UE to calculate satellite positions for Doppler and time pre-compensation. There are two formats: - PVT format: describes the (X, Y, Z) position and velocity vector (vX, vY, vZ); - Orbital parameter format: describes the orbital motion of the satellite and infers the satellite position.

[0040] - Common TA parameters: Provides common timing advance parameters to compensate for feeder link delay. Signaling includes (57 bits in total): - Absolute public TA, occupies 23 bits; - Drift of public TA: How the public TA drifts, that is, the first-order derivative of the public TA, occupies 19 bits; - Change of common TA: How the common TA changes, that is, the second-order derivative of the common TA, occupies 15 bits.

[0041] - Synchronization validity duration: used to define the validity duration of the ephemeris and public TA.

[0042] - Epoch time: the start time of the synchronization validity duration.

[0043] - K-Offset: The scheduling offset of the timing relationship in NTN.

[0044] - K-Mac: Scheduling offset used when downlink and uplink frame timing are not aligned.

[0045] - NR NTN specific information: also includes (as part of 38.331): - T-Service (sent in SIB3 of IoT NTN); - Reference location and distance thresholds: used for starting location-based measurements in RRC idle and RRC connected modes; - Neighboring cell ephemeris; - For idle mode measurements.

[0046] To achieve discontinuous coverage, the discontinuous coverage NTN provides / uses a SIB named SystemInformationBlockType32. The excerpt from TS 36.331 [2] is as follows: - SystemInformationBlockType32 IE SystemInformationBlockType32 contains satellite assistance information used to predict discontinuous coverage. SystemInformationBlockType32 is only sent in NTN cells.

[0047] SystemInformationBlockType32 information element

[0048] --ASN1START

[0049] SystemInformationBlockType32-r17 ::= SEQUENCE {

[0050] satelliteInfoList-r17 SatelliteInfoList-r17 OPTIONAL,-- Need OR

[0051] lateNonCriticalExtension OCTET STRING OPTIONAL, ... } SatelliteInfoList-r17::=SEQUENCE (SIZE (1..maxSat-r17)) OFSatelliteInfo-r17 SatelliteInfo-r17::=SEQUENCE { satelliteId-r17 INTEGER (0..255), serviceInfo-r17 SEQUENCE { tle-EphemerisParameters-r17 TLE-EphemerisParameters-r17 OPTIONAL, --Need OR t-ServiceStart-r17 TimeOffsetUTC-r17 OPTIONAL -- Need OR }, footprintInfo-r17 SEQUENCE { referencePoint-r17 SEQUENCE { longitude-r17 INTEGER (-131072..131071), latitude-r17 INTEGER (-131072..131071) } OPTIONAL, -- Need OR elevationAngles-r17 SEQUENCE { elevationAngleRight-r17 INTEGER (-14..14), elevationAngleLeft-r17 INTEGER (-14..14) OPTIONAL-- Need OP } OPTIONAL, --Need OR radius-r17 INTEGER (1..256)OPTIONAL-- Need OR } } --ASN1STOP

Table 3

[0052] According to TS 36.331 [2], SIB32 includes the following information elements: - SatelliteId: Used to associate the ephemeris field with an ID so that the UE can replace or create new entries when multiple satellites are available and the list is updated.

[0053] - TLE ephemeris parameters: Provides TLE (two-line element) parameters of satellite orbits for use in Earth mobile cells.

[0054] - T-ServiceStart: provides the time at which the area of ​​the quasi-geofixed cell will be served.

[0055] - footprintInfo: Provides information about the size and geometry of the satellite footprint: - referencePoint and radius: provide the reference point and radius of the satellite coverage area; - elevationAngles: used in Earth mobile cells to define coverage areas.

[0056] While discontinuous coverage allows UEs to save energy in deployments where there are not enough satellites to cover the entire Earth, some fundamental issues still remain in order to provide a cost-effective IoT NTN solution. Summary of the Invention

[0057] Technical issues

[0058] As communication systems evolve, there is a need to support store-and-forward based procedures in NTN deployments.

[0059] The technical subject matter pursued by the present disclosure may not be limited to the above-mentioned technical subject matter, and those skilled in the art to which the present disclosure belongs may clearly understand other technical subject matter not mentioned through the following description.

[0060] Technical Solution

[0061] According to an example of the present disclosure, a first entity in a non-terrestrial network (NTN) is provided, wherein the first entity is configured to: operate in a store-and-forward (S&F) mode based on its inclusion in a satellite providing discontinuous coverage; and the first entity is configured to send information regarding the S&F mode at the first entity to a second entity. According to another example of the present disclosure, a second entity configured to support the store-and-forward (S&F) mode is provided, the second entity comprising: a receiver; a transmitter; and a controller configured to: receive information regarding the S&F mode at the first entity from the first entity in the non-terrestrial network (NTN); and perform one or more procedures with the first entity based on the information regarding the S&F mode at the first entity. Other examples are also disclosed herein.

[0062] Certain examples / embodiments / aspects of the present disclosure are intended to, at least in part, solve, address, and / or mitigate at least one problem and / or disadvantage associated with the prior art, such as, for example, at least one problem and / or disadvantage described herein. Certain examples of the present disclosure are intended to provide at least one advantage over the prior art, such as, for example, at least one advantage described herein.

[0063] According to one aspect of the present disclosure, there is provided a first entity in a non-terrestrial network (NTN), wherein the first entity is configured to operate in a store-and-forward (S&F) mode based on its inclusion in a satellite providing discontinuous coverage; and the first entity is configured to send information about the S&F mode at the first entity to a second entity.

[0064] According to various examples, the information about the S&F mode at the first entity includes one or more of the following: an indication that the first entity is an S&F satellite, S&F eNB or S&F cell or serves an S&F satellite, S&F eNB or S&F cell, or that the first entity serves an S&F tracking area (TA), an S&F registration area (RA) or an S&F public land mobile network (PLMN); an indication that the first entity is entering S&F mode; a list of one or more of allowed procedures, disallowed procedures or restricted procedures for the first entity, the S&F satellite, the S&F eNB, the S&F cell, the S&F TA, the S&F RA or the S&F PLMN; an indication that uplink data to be forwarded by the first entity is S&F data; or an indication that downlink data to be stored and forwarded by the first entity.

[0065] According to various examples, the indication is sent via a flag in a system information block (SIB) or implicitly via an S&F specific information element.

[0066] According to various examples, when the first entity is configured to operate in the S&F mode, it is configured to perform one or more of the following procedures: tracking area update, downlink data transmission, or uplink data transmission.

[0067] According to various examples, the first entity is configured to send an indication to a user equipment (UE), the indication indicating that the UE is: capable of operating in an S&F network, capable of operating with the first entity, or capable of operating with the satellite.

[0068] According to various examples, wherein, when operating in S&F mode, the first entity is configured to store a UE context of the UE; wherein the indication is sent via a non-access stratum (NAS) or in an RRC connection release message; and / or wherein the UE is the second entity or is different from the second entity.

[0069] According to various examples, the first entity is further configured to: when operating in S&F mode in the satellite: in response to receiving an RRC connection recovery request from the UE, perform an RRC connection recovery procedure with the UE; receive uplink data from the UE; and send an RRC connection release message to the UE; based on detecting that the satellite is within the coverage of a ground station, perform a UE context recovery procedure with the second entity; and forward the uplink data to the second entity; wherein the information indicates that the uplink data is S&F data, and the information is sent during the UE context recovery procedure.

[0070] According to various examples, the first entity is further configured to: when communicatively connected to a ground station: perform a UE context recovery procedure with the second entity; and receive and store downlink data from the second entity; enter S&F mode based on detecting that the satellite is leaving the coverage of the ground station; perform an RRC connection recovery procedure with the UE in response to receiving an RRC connection recovery request from the UE; and forward the downlink data to the UE; wherein the information indicates that the downlink data will be stored and will be forwarded when the first entity is communicatively connected to the UE, and the information is sent during the UE context recovery procedure.

[0071] According to various examples, the first entity is further configured to: receive a tracking area update from a UE when operating in an S&F mode in a satellite outside the coverage of a ground station; detect that the satellite is within the coverage of the ground station and, in response thereto, connect to the ground station; forward the tracking area update to the second entity; receive a tracking area accept from the second entity; detect that the satellite is leaving the coverage of the ground station and, in response thereto, enter S&F mode; and forward the tracking area accept to the UE when a communication connection with the UE is possible.

[0072] According to various examples, wherein the first entity is a logical network entity; and wherein the first entity is configured to: transfer from the ground station to the satellite and be included in the satellite based on detecting that the satellite is leaving the coverage of the ground station; and / or transfer from the satellite to the ground station and be included in the ground station based on detecting that the satellite is entering the coverage of the ground station.

[0073] According to various examples, when the first entity is included in the ground station, the first entity is configured to: detect that the satellite is about to leave the coverage of the ground station; in response to the detection, enter S&F mode and send the information to the second entity; and receive a message from the second entity about transferring to the satellite.

[0074] According to various examples, the first entity is a satellite; and / or the first entity is an eNB.

[0075] According to various examples, the second entity is a Mobility Management Engine (MME) or a Core Network (CN); and the first entity is configured to receive one or more UE contexts in response to the information from the second entity to communicate with one or more UEs respectively.

[0076] According to another aspect of the present disclosure, a second entity configured to support a store-and-forward (S&F) mode is provided, the second entity comprising: a receiver; a transmitter; and a controller configured to: receive information about the S&F mode at a first entity in a non-terrestrial network (NTN) from the first entity; and perform one or more processes with the first entity based on the information about the S&F mode at the first entity.

[0077] According to various examples, the information about the S&F mode at the first entity includes one or more of the following: an indication that the first entity is an S&F satellite, S&F eNB, or S&F cell or serves an S&F satellite, S&F eNB, or S&F cell, or that the first entity serves an S&F tracking area (TA), an S&F registration area (RA), or an S&F public land mobile network (PLMN); an indication that the first entity is entering S&F mode; a list of one or more allowed procedures, disallowed procedures, or restricted procedures for the first entity, the S&F satellite, the S&F eNB, the S&F cell, the S&F TA, the S&F RA, or the S&F PLMN; an indication that uplink data to be forwarded by the first entity to the second entity is S&F data; or an indication that downlink data for the third entity is to be stored and forwarded when the first entity is communicatively connected with the third entity.

[0078] According to various examples, the procedure is one of: a tracking area update; a downlink data transmission; an uplink data transmission; an RRC connection recovery procedure; a UE context recovery procedure; or an RRC connection release procedure.

[0079] According to various examples, the second entity is a user equipment (UE); wherein the controller is configured to: receive an indication from the first entity or from the third entity, the indication indicating that the UE: is capable of operating in the S&F network, is capable of operating with the first entity, or is capable of operating with the satellite.

[0080] According to various examples, the indication is sent via a non-access stratum (NAS) or in an RRC connection release message.

[0081] According to various examples, the second entity is a UE, wherein the controller is configured to: during idle mode or inactive mode operation of the UE, based on the information regarding the S&F mode at the first entity, reduce the priority of the first entity or a cell of the first entity; and / or based on the information regarding the S&F mode at the first entity, deem the first entity to be barred from access by the UE. For example, the priority of the first entity or its cell is reduced due to operating in the S&F mode. For example, the first cell is barred from access by the UE due to operating in the S&F mode.

[0082] According to various examples, the second entity is a mobility management engine (MME) or a core network (CN); and the controller is configured to send one or more UE contexts to the first entity in response to the information to communicate with one or more UEs respectively.

[0083] According to various examples, the controller is configured to: perform a UE context recovery procedure with the first entity; and send downlink data to the first entity; and wherein the information indicates that the downlink data will be stored and forwarded when the first entity is communicatively connected to the UE, and the information is received during the UE context recovery procedure.

[0084] According to various examples, the controller is configured to: perform UE context recovery with the first entity; and receive uplink data from the first entity; and wherein the information indicates that the uplink data is S&F data, and the information is received during the UE context recovery process.

[0085] According to another aspect of the present disclosure, a method of a first entity in a non-terrestrial network (NTN) is provided, the first entity being configured to operate in a store-and-forward (S&F) mode based on its inclusion in a satellite providing discontinuous coverage, wherein the method includes sending information about the S&F mode at the first entity to a second entity.

[0086] According to various examples, the method further comprises the features of any of the examples described above in relation to the first entity.

[0087] According to another aspect of the present disclosure, a method of a second entity configured to support a store-and-forward mode is provided, the method comprising: receiving, from a first entity in a non-terrestrial network (NTN), information about a store-and-forward (S&F) mode at the first entity; and performing one or more procedures with the first entity based on the information about the S&F mode at the first entity.

[0088] According to various examples, the method further comprises the features of any of the examples described above in relation to the second entity.

[0089] According to another aspect of the present disclosure, a computer program is provided, comprising instructions, which, when executed by a computer or a processor, causes the computer or the processor to perform any one or more of the above methods.

[0090] According to another aspect of the present disclosure, a network is provided, comprising the first entity in any one or more of the above examples or aspects and the second entity in any one or more of the above examples or aspects.

[0091] It should be understood that the present disclosure contemplates and includes at least all combinations of the above examples and aspects.

[0092] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings.

[0093] Beneficial effects

[0094] The present disclosure provides an effective and efficient method for supporting a store-and-forward process in an NTN deployment. The beneficial effects of the present disclosure may not be limited to the above effects, and those skilled in the art of the present disclosure may clearly understand other effects not mentioned through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Embodiments / examples of the present disclosure will be further described with reference to the accompanying drawings, in which: FIG1 shows a schematic diagram of discontinuous satellite coverage according to an example of the present disclosure; Figure 2 A schematic diagram illustrating a ground station deployment according to an example of the present disclosure is shown; Figure 3 illustrating example methods (a) and (b) of an eNB indicating to an MME about a store-and-forward mode according to an example of the present disclosure; Figure 4 A method for connecting a UE to a store-and-forward satellite according to an example of the present disclosure is shown; Figure 5a A conventional recovery process related to UL data according to an example of the present disclosure is shown; Figure 5b shows a UL data process in a store-and-forward network according to an example of the present disclosure; Figure 6a A conventional recovery process related to DL data according to an example of the present disclosure is shown; Figure 6b shows a DL data process in a store-and-forward network according to an example of the present disclosure; Figure 7 The recovery process of the tracking area update according to the example of the present disclosure is shown; Figure 8 An example block diagram of a network entity according to some examples of the present disclosure is shown.

[0096] Furthermore, those skilled in the art will appreciate that elements in the drawings are shown for simplicity and may not be drawn to scale. For example, a flow chart illustrates a method in terms of the most essential steps involved to facilitate a better understanding of various aspects of the present disclosure. Furthermore, with respect to the configuration of a device, one or more components of the device may be represented in the drawings using conventional symbols, and the drawings may only show specific details relevant to an understanding of the embodiments of the present disclosure to avoid obscuring the drawings with details that would be readily apparent to one of ordinary skill in the art having the benefit of the description herein. DETAILED DESCRIPTION

[0097] The following description of examples of the present disclosure, in conjunction with the accompanying drawings, is intended to facilitate a more comprehensive understanding of certain examples of the present disclosure. This description includes various specific details to aid understanding, but these should be considered merely as illustrative. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the examples described herein without departing from the scope of the present disclosure or the present invention.

[0098] The same or similar components may be denoted by the same or similar reference numerals even though they are shown in different drawings.

[0099] For the sake of clarity and conciseness, detailed descriptions of techniques, structures, configurations, functions or processes known in the art may be omitted so as not to obscure the subject matter of the present disclosure.

[0100] The terms and words used herein are not limited to their documented or standard meanings, but are merely used to enable a clear and consistent understanding of the invention.

[0101] In the description of this specification, the words "include", "comprising" and their variations (such as "including" and "comprising") mean "including but not limited to", and are not intended to (and do not) exclude other features, elements, components, integers, steps, processes, operations, functions, characteristics, attributes and / or groups thereof.

[0102] In the description of this specification, the singular encompasses the plural unless the context requires otherwise. For example, a reference to "an object" includes a reference to one or more of such objects.

[0103] Throughout the description, the expressions "at least one of A, B and / or C" (or similar expressions) and "one or more of A, B and / or C" (or similar expressions) should be deemed to include all possible combinations, for example: A, B, C, A and B, A and C, A and B and C, respectively.

[0104] In the description of this specification, the general form of "X for Y" (where Y is a certain action, process, operation, function, activity or step, and X is a certain means for performing the action, process, operation, function, activity or step) covers means X that is specifically (but not necessarily exclusively) configured or arranged to perform Y.

[0105] 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.

[0106] Certain examples of the present disclosure relate to methods, apparatuses, and / or systems for supporting store-and-forward procedures in NTN deployments. Furthermore, certain examples of the present disclosure relate to methods and apparatuses for supporting store-and-forward procedures in NTNs with discontinuous coverage by locating the RAN in a network entity, such as a satellite or HAPS. In certain examples, the CN elements are not located in the network entity. Furthermore, certain examples of the present disclosure relate to restricting and / or enabling certain network procedures for UEs based on an eNB-based store-and-forward mode. Furthermore, certain examples of the present disclosure relate to delaying or advancing one or more portions of a recovery procedure in a store-and-forward network, such as an NTN.

[0107] The following examples apply to and use terminology related to 3GPP 4G (e.g., LTE) and / or 5G (e.g., NR). However, those skilled in the art will appreciate that the techniques disclosed herein are not limited to these examples or 3GPP 4G (e.g., LTE) and / or 5G (e.g., NR) and may be applied to any suitable system or standard, such as one or more existing and / or future wireless communication systems or standards. Those skilled in the art will appreciate that the techniques disclosed herein may be applied to any existing or future release of 3GPP 4G (e.g., LTE) and / or 5G (e.g., NR), or any other relevant standard. For example, the functions and other features of various network entities 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 considered to perform the same or similar roles, functions, operations, or purposes in a network.

[0108] A particular network entity may be implemented as a network element on dedicated hardware, as a software instance running on dedicated hardware, and / or as a virtualized function instantiated on an appropriate platform, eg, a cloud infrastructure.

[0109] It will be understood by those skilled in the art that the present invention is not limited to the specific examples disclosed herein. For example: - The technology disclosed herein is not limited to 3GPP 4G or 5G.

[0110] - One or more entities in the examples disclosed herein may be replaced by one or more alternative entities that perform equivalent or corresponding functions, processes, or operations.

[0111] - One or more messages in the examples disclosed herein may be replaced by one or more alternative messages, signals, or other types of information carriers conveying equivalent or corresponding information.

[0112] - One or more other elements, entities and / or messages may be added to the examples disclosed herein.

[0113] - In some examples, one or more non-essential elements, entities and / or messages may be omitted.

[0114] - In alternative examples, the functions, processes, or operations of a particular entity in one example may be shared by two or more separate entities.

[0115] - In alternative examples, the functions, processes or operations of two or more separate entities in one example may be performed by a single entity.

[0116] - In alternative examples, the information carried by a particular message in one example may be carried by two or more separate messages.

[0117] - In an alternative example, information carried by two or more separate messages in one example may be carried by a single message.

[0118] - In alternative examples, the order of execution of operations may be modified if possible.

[0119] - The transmission of information between network entities is not limited to the specific form, type and / or message sequence described in the examples disclosed herein.

[0120] 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 methods thereof. Such an apparatus / device / network entity may include one or more elements, such as one or more of a receiver, a transmitter, a transceiver, a processor, a controller, a module, a unit, etc., each of which is configured to perform one or more corresponding processes, operations, and / or method steps to implement the techniques described herein. For example, an operation / function of X may be performed by a module (or X module) configured to perform X. Certain examples of the present disclosure may be provided in the form of a system (e.g., a network) including one or more such apparatus / devices / network entities and / or methods thereof.

[0121] It should be understood that examples of the present disclosure may be implemented in hardware, software, or a combination of hardware and software. Certain examples of the present disclosure may provide a computer program comprising instructions or codes that, when executed, implement the method, system, and / or apparatus according to any aspect, example, and / or embodiment disclosed herein. Certain embodiments of the present disclosure provide a machine-readable storage device storing such a program.

[0122] As mentioned earlier, in NTN deployments where the number of satellites is insufficient to cover the entire Earth, discontinuous coverage allows UEs to save energy, but in order to provide a cost-effective IoT NTN solution, some fundamental issues still exist. A major issue with known NTN deployments is that satellites providing discontinuous coverage still need to connect to a ground gateway for any type of communication. Considering only coverage, a discontinuous coverage satellite network requires the same number of ground stations as a fully continuous coverage network. This is in Figure 2 This is explained in .

[0123] exist Figure 2 In (a), a continuous coverage scenario is shown, where each satellite 207 is connected to one of three ground stations (or ground gateways) 201, 203, 205 (Note: Figure 2 The twelve satellites shown in (a) are each denoted by numeral 207, but these satellites may also be numbered 207-1, 207-2, ..., 207-n, where n is equal to the total number of satellites. The corresponding cell or coverage area of ​​each satellite 207 is shown.

[0124] exist Figure 2 In (b), a discontinuous coverage scenario is shown, where there are only four satellites 217 (this number is arbitrarily chosen to demonstrate discontinuous coverage); however, three ground stations (or ground gateways) 211, 213, 215 are still set up, and each satellite 217 is connected to one of the three base stations 211, 213, 215 (Note: Figure 2 The four satellites shown in (b) are each denoted by the number 217, but these satellites may also be numbered 217-1, 217-2, ..., 217-m, where m is equal to the total number of satellites. The corresponding cell or coverage area for each satellite 217 is again shown.

[0125] Therefore, it can be seen that the number of ground stations / gateways (e.g., eNBs, gNBs, etc.) is the same regardless of whether the NTN provides continuous coverage or discontinuous coverage.

[0126] In "Novel Architecture for Cellular IoT in Future Non-Terrestrial Networks: Store and Forward Adaptations for Enabling Discontinuous Feeder Link Operation," T. Kellermann et al. propose a "store and forward" approach to address these issues, placing certain core network (CN) elements within the satellite. In summary, they propose the following: - Handling of UE Non-Access Stratum (NAS) and Mobility Management Engine (MME) timer (TXXXX etc.) issues due to delays in completing core network procedures.

[0127] - Place the MME entity or MME functionality in the satellite.

[0128] - Requires the MME on the satellite to be synchronized with the central MME entity.

[0129] - NAS procedures can be performed using entities in the satellite.

[0130] - Regenerative RAN architecture (i.e., eNB in ​​satellite).

[0131] - The Home Subscriber Server (HSS) (i.e., the EPC entity that handles UE entity authentication) on the ground, and the satellite will store and forward the packets related to these procedures (between the MME and HSS).

[0132] - Store and forward user plane in satellite.

[0133] - Methods to maintain UE context across MMEs in satellite.

[0134] This approach has the following problems: - The need to place certain core network elements in the satellite significantly increases the complexity of the core network and the satellite, and requires synchronization of the core network elements; - This requires significant integration effort and can be challenging for implementers, particularly since the core network and RAN are typically separate entities; and - This may be difficult to work with traditional terrestrial core networks.

[0135] - Some changes are required to basic core networking procedures.

[0136] Therefore, certain examples of the present disclosure provide methods, systems, apparatuses, etc. that provide a store-and-forward-based solution, where only the RAN is located (e.g., implemented) in the satellite. Other examples of the present disclosure provide methods, systems, apparatuses, etc. that provide a store-and-forward-based solution, regardless of whether only the RAN is located (e.g., implemented) in the satellite. Thus, examples of the present disclosure provide a more efficient solution to the aforementioned problems by eliminating the need to locate CN elements in the satellite. Store-and-forward is often abbreviated herein as SoF, but it should be understood that it may also be abbreviated as S&F or similar.

[0137] References to eNBs herein should be considered to refer to any base station (e.g., gNB). It should be understood that when reference is made to providing or placing an eNB in ​​a satellite, this can be considered to refer to placing a network entity (not limited to an eNB) providing eNB (or similar) functionality in the satellite. In some embodiments, the eNB can be a virtual or logical network entity.

[0138] Furthermore, references to the MME should be understood as allowing for options / examples / alternatives to be substituted with other suitable network entities (including virtual or logical network entities). For example, an Access and Mobility Management Function (AMF) or other suitable network functions could be used instead. Similarly, references to the UE should be understood as allowing for options / examples / alternatives to be substituted with other suitable network entities; for example, a relay or other node (which, in some examples, may also be considered an example of a UE).

[0139] In addition, in this disclosure, the concept of store-and-forward satellite may also be referred to as "discontinuous feeder link", "intermittent feeder link", etc. In other words, these terms may be used interchangeably or in a related manner, and other terms may be used if necessary.

[0140] Certain embodiments of the present disclosure provide, but are not limited to, methods for implementing RAN-based store-and-forward technology based on Radio Resource Control (RRC) suspend / resume. Thus, simply by placing the eNB in ​​the satellite, any data packets on the interface between the eNB and other nodes in the core network are "stored" and "forwarded" later. This can also be considered a proxy interface performing the same action.

[0141] In various examples, the eNB indicates whether it is a store-and-forward (SoF) satellite, a store-and-forward eNB, or a store-and-forward cell (ie, the eNB will indicate the relevant store-and-forward capabilities / arrangements). As will be explained below, this is useful in many ways.

[0142] Since only the eNB is in the satellite, according to various embodiments, there are many procedures (e.g., UE-related, eNB-related, or general network-related) that may not be performed at all, may be limited, or may take a long time. These procedures may include one or more of the following: - Attachment process (core network process), - separation process (core network process), - Service Request Process (Core Network Process), - Inter-satellite handover (RAN procedure).

[0143] In some examples, the core network procedure examples described above may be (primarily) initiated by the UE, for example, by transparently sending a NAS message to the MME. In some examples, the RAN procedure examples described above may be initiated by a UE handover between a first eNB and a second eNB, which may also involve instructions to the MME. Therefore, in various embodiments, it should be understood that the restricted procedure may be considered to be associated with an initiating entity.

[0144] Therefore, according to various examples of the present disclosure, if a UE needs to perform one of these procedures, it will need to do so very slowly (due to the numerous round trips with the MME) or while connected to a satellite connected to a ground station. Therefore, in one embodiment, the UE is allowed to perform one or more of the above procedures only when a satellite is not included in a SoF network. The above procedures can also be performed, for example, in a terrestrial network or in a geostationary network with poor coverage, and then continue to use only SoF satellites. In other words, the functions performed by the above procedures can be considered pre-loaded.

[0145] According to various embodiments, to facilitate limiting one or more procedures, the eNB may signal or indicate (e.g., in a broadcast) to the UE, MME, or other network entity that it belongs to (or serves) a store-and-forward satellite, a store-and-forward eNB, a store-and-forward cell (or a tracking area, a registration area, a country). For example, the eNB may broadcast an indication in system information that it is a SoF cell, a SoFeNB, a SoF satellite, etc. In some examples, the eNB may additionally (or even alternatively) transmit a list of allowed or disallowed / restricted procedures on the store-and-forward satellite, the store-and-forward eNB, and / or the store-and-forward cell (or a tracking area, a registration area, a country).

[0146] In various examples, the above-mentioned indication / information can be sent via a flag or implicitly based on a store-and-forward (or similar) specific information element (e.g., a system information block (SIB)). Regarding the location of this indication, it can be sent in any SIB, including but not limited to SIB1, SIB31 (i.e., an NTN-specific SIB), or SIB32 (i.e., an SIB for discontinuous coverage). As an example of discontinuous coverage signaling, the eNB can indicate upcoming satellites / eNBs / cells. An upcoming satellite can be considered, for example, a satellite that will pass over the UE / the area / UE's operating area. In another definition, an upcoming satellite can be a satellite that will serve the UE in the future (e.g., satellites typically orbit, and the network or UE can roughly predict when a new satellite will arrive to serve the UE) and is a store-and-forward satellite / eNB / cell. In another example, this information can be indicated in an idle mode (or inactive mode) configuration, such as provided by an RRC Connection Release (RRCConnectionRelease).

[0147] In other examples, a public land mobile network (PLMN) or frequency may be considered to operate in a store-and-forward manner, and signaling may be provided to indicate this. In a further example, certain areas (e.g., a Tracking Area (TA), Registration Area (RA), or country) may operate in a store-and-forward manner, and signaling may be provided to indicate this. This may require more advanced signaling (e.g., requiring the transmission of more information than in the examples above), but the benefit is that the UE can clearly understand where store-and-forward operation is possible (e.g., within the entire PLMN, TA, RA, or country, or on specific frequencies).

[0148] In certain embodiments, the UE can utilize the indication that a particular satellite (or eNB, or cell) is a store-and-forward entity (e.g., in addition to the UE's use of this indication to identify the store-and-forward nature of the satellite) to deprioritize cells operating in this mode, such as during cell selection or cell reselection in idle or inactive mode. This can be particularly useful if the UE needs to perform any potentially restricted procedures (as described above). In various examples, a SoF satellite / eNB / cell may be considered prohibited (e.g., by the UE) for certain services (e.g., providing or performing specific (e.g., provisioning, subscription, indication, etc.) services). Examples of such services include time-sensitive services such as emergency indications and voice (VoIP, VoLTE) services.

[0149] In various examples, certain procedures (e.g., UE-related, eNB-related, or general network-related) may be allowed for SoF satellites (or eNBs, cells). It should be understood that the various examples include both allowed procedures and restricted procedures (e.g., the restricted procedures discussed above). Examples of allowed procedures are as follows (i.e., may include one or more of the following): - Tracking area updates; - Downlink data transmission; - Uplink data transmission.

[0150] In some embodiments, in order to support or facilitate the UE to operate in a store-and-forward NTN, it may be necessary to send signaling to the UE. For example, one or more of the following signaling examples may be provided to the UE (these signaling may be performed individually (e.g., each indication is included in a separate message) or in any combination (e.g., multiple indications are included in a single message)): - signalling indicating that the UE can operate in a store-and-forward network and / or can operate with a store-and-forward satellite (or SoF eNB, SoF cell), e.g., an indication of this can be sent to the UE; - Signalling indicating under which conditions the UE can operate in a store-and-forward network, for example: - Indicates how long the UE can operate in a store-and-forward network, and / or - Indicates in which geographical areas the store-and-forward can operate (i.e. in which areas the UE can operate in the SoF network, or in which areas the SoF network can operate); - The UE may indicate that it is capable of operating in a store-and-forward network. Such an indication may be provided to the eNB and then to the MME, where the MME may decide whether the UE is to operate in a SoF network.

[0151] In various examples, the above content may be indicated by signaling through the MME via the NAS when the UE releases / redirects the connection through RRC release, or may be broadcast in a system information block.

[0152] In certain embodiments of the present disclosure, methods related to store-and-forward are based on RRC procedures, such as the RRC recovery procedure, through which a satellite (i.e., an eNB) retains (e.g., stores) the UE context of a UE with which it is communicating. To this end, in some examples, the UE may need to be capable of the RRC recovery procedure in order to perform store-and-forward communication.

[0153] Therefore, in one embodiment, a UE can only operate in store-and-forward "mode" (i.e., served by a SoF satellite, SoF eNB, SoF cell, etc.) if the eNB (i.e., eNB and / or satellite) has an available UE context (or a valid UE context). In one embodiment, the UE can be allowed to be in store-and-forward "mode" if its RRC connection is suspended. This can be sent, for example, in an RRC Connection Release message or in a NAS message from the CN.

[0154] In one consideration, since the core network should operate like a normal terrestrial core network, the core network may not have sufficient information when the satellite leaves the terrestrial network.

[0155] To implement store-and-forward operation, the eNB may need to be located in the satellite, a so-called regenerative architecture. Therefore, in one embodiment, the eNB is dynamically transferred to a store-and-forward satellite. This can occur when the eNB / satellite is about to leave the ground station's coverage area. In further embodiments, the eNB can similarly be transferred back to the ground station when the eNB / satellite reaches the ground station's coverage area.

[0156] In other words, in some examples, the eNB can be considered a role that can be transferred between different network entities, such as between a ground station and a satellite. For example, the eNB is a logical network entity or a virtual network entity. Transfers can be triggered by the eNB entity itself or by another network entity, such as the MME.

[0157] In other embodiments, the eNB may announce to the MME that it is entering store-and-forward mode. In this example, the MME may notify other network entities and / or functions that the eNB may be or is entering store-and-forward mode. It should be understood that other network entities besides the MME may be substituted. For example, the eNB (or gNB) may announce this to the Access and Mobility Management Function (AMF) or other appropriate network functions (NFs).

[0158] In another example, the MME knowing that the eNB is entering store-and-forward mode may defer, store, cancel, reject, or terminate any NAS procedures or signaling interactions with the eNB and / or UE.

[0159] The above content (e.g., transferring the eNB to a satellite, etc.) may be sent, for example, via the S1AP interface in any of the following messages / procedures: - eNB configuration update procedure (ENB CONFIGURATION UPDATE); - S1 SETUP REQUEST process.

[0160] When the eNB indicates to the MME that it will enter store-and-forward mode, the MME may preload (preconfigure / forward) the eNB with the UE context required to communicate with the desired UE.

[0161] Figure 3 Some examples consistent with the present disclosure are shown, which illustrate examples of an eNB issuing an indication to an MME when entering or about to enter SoF mode.

[0162] exist Figure 3 In (a), in step 1 (311), the satellite / eNB initially maintains contact with the ground station (e.g., has a connection with the MME or other appropriate network entity (e.g., AMF)). In step 2 (313), the satellite / eNB detects that it is about to lose ground station coverage. In step 3 (315), the satellite / eNB notifies, announces, etc. to the MME that it will enter SoF mode.

[0163] exist Figure 3 In step 1 (321) of (b), the satellite / eNB initially maintains contact with the ground station (e.g., has a connection with the MME or other appropriate network entity such as the AMF). In step 2 (323), the satellite / eNB detects that it is about to lose ground station coverage. In step 3 (325), the satellite / eNB notifies, announces, etc. to the MME that it will enter SoF mode. In step 4a (327), the MME sends a message to the satellite / eNB regarding the transfer of the eNB to the satellite. In step 4b (329), the MME sends a message to the satellite / eNB regarding the transfer of the UE context to the satellite.

[0164] Figure 4 An example of a process for a UE to connect to a store-and-forward satellite according to an example of the present disclosure is shown.

[0165] In operation 1 (410), a UE context may be established and an RRC suspension resumption procedure may be set up.

[0166] In operation 2 (420), the network may determine whether the UE can operate in a store-and-forward network. In one example, this may be determined based on whether the UE will be in an area of ​​store-and-forward operation; in another example, this may be determined based on the services required by the UE.

[0167] In operation 3 (430), the network may send signaling indicating that the UE can operate in a store-and-forward network. For example, such signaling may be sent by the NAS or by the eNB in ​​an RRC Connection Release message.

[0168] In operation 4 (440), the MME transfers the required UE context to the SoF eNB (eg, satellite). In an example, this step may be performed when the network determines that the UE is allowed to operate in the SoF network.

[0169] In operation 5 (450), the UE may detect the SoF eNB.

[0170] In operation 6 (460), the UE may connect to the SoF eNB.

[0171] It should be understood that Figure 4 One or more of the operations shown in FIG. 2 may be omitted, replaced, or reordered to provide further examples of the present disclosure. As just one example, various embodiments include operations 2 and 3, which simply involve determining and signaling that the UE can operate in a SoF network. Of course, all other combinations of steps are contemplated herein.

[0172] According to certain embodiments, in order for the signaling to function correctly, some procedures with the core network may need to be performed in advance, and / or some procedures may need to be performed delayed.

[0173] For example, for uplink, in a traditional network, the UE context recovery procedure is performed before the UE sends uplink data to the eNB. Figure 5a An example of this is shown. However, in a store-and-forward network, this may not be feasible.

[0174] Therefore, in an embodiment of the present disclosure, the UE context recovery process is delayed until the eNB reaches the terrestrial gateway and connects to the MME. Figure 5b Such an example is shown, which illustrates an example method flow of an uplink data recovery process in a store-and-forward network according to various embodiments of the present disclosure.

[0175] exist Figure 5a, a conventional recovery process is shown. In step 1 (501), the UE may send an RRCConnectionResumeRequest message to the eNB. In step 2 (503), the eNB may send an RRCConnectionResume message to the UE. In step 3 (505), RRC is restored, for example, the UE may restore SRBs and DRBs, access stratum security (AS Security) may be restored, and the UE may enter the RRC_CONNECTED state. In step 4 (507), the UE may send an RRCConnectionResumeComplete message to the eNB. In step 5 (509), the eNB may send a UEContextResumeRequest message to the MME. In step 6 (511), the MME (and SGW) may modify the bearer (e.g., for the UE). In step 7 (513), the MME may send a UEContextResumeResponse to the eNB. In step 8 (515), the UE may send uplink (UL) data to the eNB, and the eNB may forward this data until it reaches the SGW. In step 9 (517), the eNB may send an RRC Connection Release message to the UE. In step 10 (519), the UE release occurs.

[0176] supply Figure 5a It is for the purpose of Figure 5b 5B shows an example of a UL data process in a store-and-forward network using RRC recovery.

[0177] refer to Figure 5b , in step 1 ( 551 ), the UE may send an RRC connection resumption request (eg, in a message, an RRC message, etc.) to the eNB (eg, via a Uu interface).

[0178] In step 2 (553), the eNB may send an RRC Connection Resume (eg, in a message, an RRC message, etc.) to the UE (eg, over a Uu interface).

[0179] In step 2 (555), the UE may restore SRB and DRB, AS sec (AS Security) may be re-established, and the UE may enter the RRC_CONNECTED state.

[0180] In step 4 (557), the UE may send an RRC Connection Recovery Complete (eg, in a message, an RRC message, etc.) to the eNB (eg, over a Uu interface).

[0181] In step 5 (559), the UE may send UL data to the eNB (eg, via the Uu interface).Thus, it can be seen that the UE context recovery procedure is delayed in various embodiments.

[0182] In step 6 (561), the eNB may send an RRC connection release (eg, in a message, an RRC message, etc.) to the UE (eg, over a Uu interface), eg, when UL data is received.

[0183] In step 7 (563), UE release occurs. For example, the UE is released while the RRC connection is suspended.

[0184] Steps 1 to 7 may be performed, for example, when the eNB is operating in a SoF state (ie, the eNB is placed in a satellite).

[0185] In step 8 (565), the eNB may determine or detect that it is in contact with a ground station. Optionally, the eNB may transfer to the ground station.

[0186] In step 9 (567), the eNB may send a UE context restore request (e.g., in a message) to the MME (e.g., via the S1 interface). For example, the eNB may indicate that the data (UL data) is store-and-forward data. This may inform the core network that the UE may not be reachable at this time.

[0187] In step 10 (569), the MME and SGW may modify the bearer (eg, based on the UE context restore request).

[0188] In step 11 (571), the MME may send a UE context restoration response to the eNB (eg, via the S1 interface).

[0189] In step 12 (573), the eNB may deliver (eg, transmit, forward, etc.) the UL data to the SGW (eg, from the eNB to the MME and then to the SGW).

[0190] Therefore, it can be seen that the processes according to various embodiments of the present disclosure are different from the conventional processes.

[0191] It should be understood that Figure 5b One or more of the operations shown in the figure may be omitted, replaced, or reordered to provide other examples of the present disclosure. For example, a feature where the context recovery process is delayed (e.g., compared to forwarding of UL data) may be of interest, and only steps related to this feature may constitute another embodiment. Of course, all other combinations of steps are contemplated.

[0192] In another embodiment of the present disclosure, reference may also be made to Figure 5b The method / process can be described as follows: 1. Uu: RRC connection recovery request 2. Uu: RRC connection recovery 3. UE: SRB and DRB are restored, AS sec is re-established, and the UE enters RRC_CONNECTED 4. Uu: RRC connection recovery completed 5. Uu: UL data transmission and storage in eNB - For example, the eNB can store and forward this data until it reaches the terrestrial gateway 6. Uu: UE is released - The UE is released while the RRC connection is suspended 7. UE is released 8. eNB: eNB is connected to the ground station 9. S1: eNB sends UE context recovery request to MME - For example, the eNB can indicate that the data is store-and-forward data. This tells the core network that it may not be able to reach the UE at the moment.

[0193] 10. Modify the load

[0194] 11. S1: MME sends MME UE Context Recovery Response

[0195] 12. UL data is transferred from MME to S-GW

[0196] For downlink data, according to various examples of the present disclosure, the UE context recovery procedure is performed in advance (eg, compared to conventional procedures). DL data may also be sent in advance for storage by the eNB.

[0197] Figure 6aA conventional recovery process for delivering downlink data is shown. In step 1 (601), the MME pages the eNB, and the eNB pages the UE. In step 2 (603), the UE sends an RRC Connection Recovery Request to the eNB. In step 3 (605), the eNB sends an RRC Connection Recovery to the UE. In step 4 (607), RRC is recovered, for example, the UE can recover SRBs and DRBs, ASsec (AS Security) can be re-established, and the UE can enter the RRC_CONNECTED state. In step 5 (609), the UE can send an RRC Connection Recovery Complete to the eNB. In step 6 (611), the eNB can send a UE Context Recovery Request message to the MME. In step 7 (613), the MME (and SGW) can modify the bearer (for example, for the UE). In step 8 (615), the MME can send a UE Context Recovery Response to the eNB. In step 9 (617), the SWG may send (e.g., forward, deliver, etc.) downlink (DL) data to the eNB, and the eNB may send (e.g., forward, deliver, etc.) DL data to the UE. In step 10 (619), the eNB sends an RRC connection release to the UE. In step 11 (621), the UE release occurs.

[0198] supply Figure 6a It is for the purpose of Figure 6b shown) for comparison, Figure 6b An example of a DL data procedure in a store-and-forward network using RRC recovery is shown.

[0199] refer to Figure 6b In step 1 (651), the eNB may determine that it will be in contact with a ground station, or may be in a state of being in contact with a ground station.

[0200] In step 2 (653), the MME may page the eNB (eg, via the S1 interface).

[0201] In step 3 (655), the eNB may send a UE context restore request (e.g., in a message) to the MME (e.g., via the S1 interface). For example, the eNB may indicate that the UE is unreachable and that the data is stored and will be forwarded once the UE is reachable. Optionally, it may also indicate whether the satellite / eNB is expected to contact the UE.

[0202] In step 4 (657), the MME and SWG may modify the bearer (eg, based on the UE context restore request).

[0203] In step 5 (659), the MME may send a UE context response (eg, in a message) to the eNB.

[0204] In step 6 (661), the eNB may receive the DL data from the SGW. For example, the data is stored in the eNB and delivered once the UE is reachable. In another example, a timer is configured to determine how long the DL data is stored in the eNB. Upon expiration of the timer, the DL data packet may be deleted or marked for deletion. This helps ensure that the memory of the SoF entity is not overloaded.

[0205] In step 7 (663), the eNB may enter SoF mode and reach the UE. For example, the eNB detects that it has lost contact with the ground station (e.g., no connection, weak connection, out of coverage) and therefore enters SoF mode (e.g., transfers to satellite). Once in SoF mode, the eNB can reach the UE (e.g., the eNB / satellite's coverage reaches the UE).

[0206] In step 8 (665), the eNB may page the UE (eg, via the Uu interface).

[0207] In step 9 (667), the UE may send (eg, in a message) an RRC Connection Resume Request to the eNB (eg, over the Uu interface).

[0208] In step 10 (669), the eNB may send (eg, in a message) an RRC Connection Resume to the UE (eg, over the Uu interface).

[0209] In step 11 (671), RRC recovery occurs at the UE (e.g., in response to receiving an RRC connection resume). For example, the UE may restore SRBs and DRBs, re-establish AS sec (AS Security), and enter the RRC_CONNECTED state.

[0210] In step 12 (673), the UE may send (eg, in a message) RRC Connection Recovery Complete to the eNB (eg, over the Uu interface).

[0211] In step 13 (675), the eNB may send (eg, forward, deliver, etc.) the DL data to the UE (eg, over a Uu interface) (eg, in a message).

[0212] In step 14 (677), the eNB may send (eg, in a message) an RRC Connection Release to the UE (eg, over the Uu interface).

[0213] In step 15 (679), UE release occurs.

[0214] It should be understood that Figure 6bOne or more operations shown in the figure may be omitted, replaced, or reordered to provide other examples of the present disclosure. For example, the feature of executing the context recovery procedure in advance (e.g., compared to DL data forwarding) may be of interest, and thus only steps related to this feature may constitute another embodiment. For example, in one embodiment, only steps 3, 5, and 7 and one or more of steps 9 to 14 are included, thereby highlighting that the UE context recovery procedure is executed before the RRC connection is restored (compared to the UE context recovery procedure). Figure 6a Of course, all other combinations of steps are considered here.

[0215] In another embodiment of the present disclosure, reference may also be made to Figure 6b The method / process can be described as follows: 1. eNB is connected to the ground station 2. S1: eNB receives paging from MME 3. S1: eNB sends "UE Context Recovery Request" to MME 4. Modify the bearer 5. S1: MME sends "UE Context Response" message to eNB - The eNB can indicate that the UE is unreachable and the data will be stored and forwarded once the UE is reachable. This can also indicate whether the satellite / eNB is expected to contact the UE.

[0216] 6. Sending DL data from S-GW to eNB

[0217] - Data is stored in the eNB and delivered once it reaches the UE.

[0218] - In an embodiment, a timer is configured to determine the duration for which DL data is stored in the eNB.

[0219] 7. eNB enters SoF mode and reaches UE

[0220] 8. Uu: eNB paging UE

[0221] 9. Uu: RRC connection recovery request

[0222] 10. Uu: RRC connection recovery

[0223] 11. UE: SRB and DRB are restored, AS sec is re-established, and the UE enters RRC_CONNECTED

[0224] 12. Uu: RRC connection recovery completed

[0225] 13. Uu: DL data transmission

[0226] 14. Uu: Release UE by releasing the RRC connection

[0227] 15. UE is released

[0228] Figure 7 An example of a tracking area update resumption procedure according to the present disclosure is shown.

[0229] In step 1 (710), the eNB may enter SoF mode and reach the UE (eg, the coverage of the eNB reaches the UE).

[0230] In step 2 (720), the UE may send a Tracking Area Update (e.g., a NAS message) to the eNB (e.g., over the Uu interface), which may be stored in the eNB. For example, this may include an indication that the UE is in SoF mode.

[0231] In step 3 (730), the eNB may be in contact with the ground station. For example, the eNB may determine the existence of the ground station, connect to the ground station, etc. after leaving the coverage area of ​​the ground station.

[0232] In step 4 (740), the eNB may send (eg, forward) the tracking area update to the MME (eg, via the S1 interface).

[0233] In step 5 (750), the MME may send a Tracking Area Accept to the eNB after receiving the Tracking Area Update (eg, in response to receiving the TA Update). The Tracking Area Accept may be stored in the eNB.

[0234] In step 6 (760), the eNB may enter SoF mode and reach the UE. For example, the eNB may move out of coverage or be connected to a ground station, so the eNB may transfer to a satellite whose coverage reaches the UE. In this example, the eNB may page the UE for downlink data.

[0235] In step 7 (770), the eNB may send (eg, forward) a Tracking Area Accept to the UE.

[0236] It should be understood that Figure 7 One or more of the operations shown in the figure may be omitted, replaced, or reordered to provide other examples of the present disclosure. For example, attention may be paid to the steps related to the eNB storing received data until it establishes contact with a ground station to forward the data to the MME (e.g., steps 2 to 4), and / or until the eNB enters SoF mode and reaches the UE to forward the data (e.g., steps 5 to 7). Of course, all other combinations of steps are contemplated herein.

[0237] In another embodiment of the present disclosure, reference may also be made to Figure 7The method / process can be described as follows: 1. The eNB enters SoF mode and reaches the UE.

[0238] 2. Uu: The UE sends a Tracking Area Update (NAS message), which is stored by the eNB. - For example, this may include an indication that the UE is in SoF mode.

[0239] 3. The eNB is connected to the ground station.

[0240] 4. S1: Tracking Area Update NAS message is forwarded to the MME.

[0241] 5. S1: After receiving the tracking area update, the MME replies with tracking area acceptance, which is then stored by the eNB.

[0242] 6. The eNB enters SoF mode and reaches the UE; - For example, the UE will be paged regarding its downlink data.

[0243] 7. Uu: eNB forwards the tracking area acceptance to the UE.

[0244] Figure 8 A block diagram illustrates an exemplary network entity 800 (or electronic device, or network node, etc.) that may be used in examples of the present disclosure. For example, the UE, eNB, device, network entity, network node, network function, network, etc. described in any of the above embodiments / examples may be implemented by or include the network entity 800 (or combined with the network entity 200). For example, the eNB, UE, or MME in any of the above examples / embodiments / aspects may be implemented by or combined with the network entity 800, or include the network entity 800.

[0245] The network entity 800 includes a controller 805 (or at least one processor) and at least one of a transmitter 801, a receiver 803 or a transceiver (not shown). It should be understood that the network entity may also include an antenna.

[0246] For example, the controller 805 may be configured to control the network entity 800 to perform any one or more of the aforementioned features, operations, or functions related to the network entity; the transmitter 801 may be configured to transmit any one or more of the aforementioned information, signals, data, etc.; and the receiver 803 may be configured to receive any one or more of the aforementioned information, signals, data, etc. A person skilled in the art will understand how to provide such a network entity 800 consistent with any one or more of the examples / embodiments disclosed herein.

[0247] For all examples / aspects / embodiments described above / in this document, it should be considered that the corresponding features / operations can be applied in any order or combination, and there is further the possibility of omitting one or more features / operations.

[0248] Furthermore, all of the above examples, embodiments, aspects, etc., are applicable to at least LTE, NR, NR NTN, or IoT NTN (note that this list is provided only as examples and should not be considered limiting), including any relevant signaling / messages on any interface, such as X2, Xn, NG, S1, F1, etc. (again, this list is provided only as examples and should not be considered limiting). It should be understood that in each of the above examples, embodiments, aspects, etc., one or more features or operations may be omitted, modified, or moved (for example, the order of the features or operations may be changed) as necessary and appropriate.

[0249] In addition, when a figure illustrating an example method flow includes text related to a specific step / operation, it should be understood that the text is merely an example of the corresponding step / operation and a more general definition (such as that found in the description of the corresponding step) may apply to the step / operation.

[0250] In addition, with respect to all of the above, one or more features or operations in any example / embodiment may be combined with features or operations in any other example / embodiment. That is, the present disclosure should be deemed to include all suitable combinations of the examples / embodiments disclosed herein, as well as suitable combinations of individual features within and between each example / embodiment.

[0251] The techniques described herein can be implemented using any appropriately configured device and / or system. Such a device and / or system can be configured to perform a method according to any aspect, embodiment, or example disclosed herein. Such a device can include one or more elements, such as one or more of a receiver, a transmitter, a transceiver, a processor, a controller, a module, a unit, etc., each of which is configured to perform one or more corresponding processes, operations, and / or method steps to implement the techniques described herein. For example, the operation / function of X can be performed by a module (or X module) configured to perform X. One or more elements can be implemented in the form of hardware, software, or any combination of hardware and software.

[0252] It should be understood that the 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, such as a storage device such as ROM (whether erasable or rewritable), or in the form of memory such as RAM, a memory chip, device, or integrated circuit, or on an optical or magnetically readable medium such as a CD, DVD, disk, or tape.

[0253] It should be understood that storage devices and storage media are embodiments of machine-readable storage suitable for storing a program or storing a program comprising instructions that, when executed, implement certain examples of the present disclosure. Thus, 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 provide a machine-readable storage storing such a program. Furthermore, such a program may be electronically transmitted via any medium, for example, a communication signal carried by a wired or wireless connection.

[0254] While the invention 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 details may be made therein without departing from the scope of the invention.

[0255] Please note that the contents of all papers and documents related to this application and filed concurrently with or before this specification, as well as all papers and documents opened to public inspection with this specification, are incorporated herein by reference.

[0256] Acronyms and Definitions

[0257] 3GPP: Third Generation Partnership Project

[0258] 5G: Fifth Generation

[0259] 5GC: 5G core network

[0260] 5QI: 5G QoS Identifier

[0261] 5GS: 5G system

[0262] 5GSM: 5G System Session Management

[0263] 5GMM: 5G System Mobility Management

[0264] AF: Application Function

[0265] AI: Artificial Intelligence

[0266] AM: Confirmation mode

[0267] AMF: Access and Mobility Management Function

[0268] AS: Application Server

[0269] ASP: Application Service Provider

[0270] AUSF: Authentication Server Function

[0271] CDN: Content Delivery Network

[0272] DCAF: Data Collection Application Function

[0273] DNAI: Data Network Access Identifier

[0274] DNN: Data Network Name

[0275] DNS: Domain Name Server

[0276] DRB: Data Radio Bearer

[0277] eNB: Evolved Node B

[0278] EPC: Evolved Packet Core

[0279] FEC: Forward Error Correction

[0280] FQDN: Fully Qualified Domain Name

[0281] GBR: Guaranteed Bit Rate

[0282] gNB: Next Generation Node B

[0283] GPSI: General Public Subscription Identifier

[0284] HSS: Home Subscriber Server

[0285] IAB: Integrated Access and Postback

[0286] ID: Identity / Identifier

[0287] IIoT: Industrial Internet of Things

[0288] IMEI: International Mobile Equipment Identity

[0289] IP: Internet Protocol

[0290] I-SMF: Intermediate SMF

[0291] LADN: Local Area Network

[0292] LL SSM: Lower Level SSM

[0293] MBMS: Multimedia Broadcast / Multicast Service

[0294] MBS: Multicast / Broadcast Service

[0295] MBSF: Multicast / Broadcast Service Function

[0296] MBSTF: Multicast / Broadcast Service Transport Function

[0297] MB-SMF: Multicast / Broadcast Session Management Function

[0298] MB-UPF: Multicast / Broadcast User Plane Function

[0299] ML: Machine Learning

[0300] MME: Mobility Management Entity

[0301] MN: Master Node

[0302] MNO: Mobile Network Operator

[0303] MT: Mobile Terminal

[0304] NAS: Non-Access Stratum

[0305] NEF: Network Exposure Function

[0306] NRF: Network Storage Function

[0307] NG-RAN: Next Generation Radio Access Network

[0308] NG-eNB: Next Generation eNB

[0309] NSA: Non-Standalone Networking

[0310] NSSF: Network Slice Selection Function

[0311] NTN: Non-Terrestrial Network

[0312] NW: Network

[0313] NWDAF: Network Data Analysis Function

[0314] OS: operating system

[0315] OSAPP: OS application

[0316] PCF: Policy Control Function

[0317] PCO: Protocol Configuration Options

[0318] PDR: Group Detection Rules

[0319] PDU: Protocol Data Unit

[0320] PTM: Point-to-Multipoint

[0321] PTP: Point to Point

[0322] QFI: QoS Flow Identifier (ID)

[0323] QoS: Quality of Service

[0324] RACH: Random Access Channel

[0325] RAN: Radio Access Network

[0326] RRC: Radio Resource Control

[0327] RSD: Routing Descriptor

[0328] SA: Standalone Network

[0329] SDAP: Service Data Adaptation Protocol

[0330] SDU: Service Data Unit

[0331] SGW: Serving Gateway

[0332] SIM: Subscriber Identity Module

[0333] SLA: Service Level Agreement

[0334] SM: Session Management

[0335] SMF: Session Management Function

[0336] SN: Secondary Node

[0337] S-NSSAI: Single Network Slice Selection Assistance Information

[0338] SSB: Synchronous Signal Block

[0339] SSM: Source Specific IP Multicast Address

[0340] SSC: Session and Service Continuity

[0341] SRB: Signaling Radio Bearer

[0342] SUPI: Subscription Persistent Identifier

[0343] TA: Tracking Area

[0344] TAI: Tracking Area Identifier

[0345] TE: terminal equipment

[0346] TM: Transparent Mode

[0347] TMGI: Temporary Mobility Group Identifier

[0348] TS: Technical Specification

[0349] UDM: Unified Data Management

[0350] UDR: Unified Data Repository

[0351] UE: User Equipment

[0352] UL: Uplink

[0353] UM: Unconfirmed Mode

[0354] UP: User plane

[0355] UPF: User Plane Function

[0356] URLLC: Ultra-Reliable Low Latency Communication

[0357] URSP: UE Routing Selection Policy

Claims

1. A first entity in a non-terrestrial network (NTN), wherein the first entity is configured to: Operating in a store-and-forward (S&F) mode based on its inclusion in a satellite providing discontinuous coverage; and in, The first entity is configured to send information about the S&F mode at the first entity to a second entity.

2. The first entity according to claim 1, wherein: The information about the S&F mode at the first entity includes one or more of the following: an indication that the first entity is a S&F satellite, a S&F eNB, or a S&F cell or serves a S&F satellite, a S&F eNB, or a S&F cell, or that the first entity serves a S&F tracking area TA, a S&F registration area RA, or a S&F public land mobile network PLMN; an indication that the first entity is entering the S&F mode; comprising a list of one or more of allowed procedures, disallowed procedures, or restricted procedures for the first entity, the S&F satellite, the S&F eNB, the S&F cell, the S&F TA, the S&F RA, or the S&F PLMN; an indication that the uplink data to be forwarded by the first entity is S&F data; or an indication that the first entity will store and forward downlink data, The indication is sent via a flag in a system information block SIB, or is implicitly sent via an information element specific to S&F.

3. The first entity according to claim 1 or 2, wherein: When the first entity is configured to operate in the S&F mode, the first entity is configured to perform one or more of the following processes: Tracking area updates; downlink data transmission; or Uplink data transmission.

4. The first entity according to any one of claims 1 to 3, wherein: The first entity is configured to send an indication to a user equipment (UE), the indication indicating that the UE is capable of operating in an S&F network, capable of operating with the first entity, or capable of operating with the satellite, wherein when the first entity operates in the S&F mode, the first entity is configured to store a UE context of the UE; The indication is sent via a non-access stratum (NAS) or in an RRC connection release message; and / or The UE is the second entity or is different from the second entity.

5. The first entity according to any one of claims 1 to 3, Further configuration is: When operating in the S&F mode in the satellite: In response to receiving an RRC connection recovery request from the UE, performing an RRC connection recovery procedure with the UE; receiving uplink data from the UE; as well as Sending an RRC connection release message to the UE; performing a UE context recovery procedure with the second entity based on detecting that the satellite is within coverage of the ground station; as well as forwarding the uplink data to the second entity; wherein the information indicates that the uplink data is S&F data, and the information is sent during the UE context recovery process, or Further configuration is: When communicatively connected to a ground station: performing a UE context recovery procedure with the second entity; and receiving and storing downlink data from the second entity; Entering the S&F mode based on detecting that the satellite is leaving the coverage area of ​​the ground station; In response to receiving an RRC connection recovery request from the UE, performing an RRC connection recovery procedure with the UE; and forwarding the downlink data to the UE; wherein the information indicates that the downlink data will be stored and will be forwarded when the first entity is communicatively connected to the UE, and the information is sent during the UE context recovery process, or Further configuration is: receiving a tracking area update from a UE when operating in said S&F mode in said satellite outside of ground station coverage; detecting that the satellite is within coverage of the ground station and, in response thereto, connecting to the ground station; forwarding the tracking area update to the second entity; receiving a tracking area accept from the second entity; detecting that the satellite is leaving coverage of the ground station and, in response thereto, entering the S&F mode; and When the communication connection with the UE is established, the tracking area acceptance is forwarded to the UE.

6. The first entity according to any one of claims 1 to 4, wherein: The first entity is a logical network entity; and Wherein, the first entity is configured as: transfer from the ground station to the satellite and include in the satellite based on detecting that the satellite is leaving coverage of the ground station; and / or transferring from the satellite to the ground station and being included in the ground station based on detecting that the satellite is entering coverage of the ground station, When the first entity is included in the ground station, the first entity is configured as follows: detecting that the satellite is about to leave the coverage area of ​​the ground station; In response to the detecting, entering the S&F mode and sending the information to the second entity; and A message is received from the second entity regarding transfer to the satellite.

7. The first entity according to any one of claims 1 to 5, wherein: The first entity is a satellite; and / or The first entity is an eNB.

8. The first entity according to any one of claims 1 to 7, wherein: The second entity is a mobility management engine MME or a core network CN; as well as The first entity is configured to: receive one or more UE contexts in response to the information from the second entity, so as to communicate with one or more UEs respectively.

9. A second entity configured to support a store-and-forward (S&F) mode, the second entity comprising: Receiver; transmitter; as well as Controller, configured as: receiving, from a first entity in a non-terrestrial network (NTN), information about an S&F mode at the first entity; as well as One or more processes are performed with the first entity based on the information regarding the S&F mode at the first entity.

10. The second entity according to claim 9, wherein: The information about the S&F mode at the first entity includes one or more of the following: an indication that the first entity is a S&F satellite, a S&F eNB, or a S&F cell or serves a S&F satellite, a S&F eNB, or a S&F cell, or that the first entity serves a S&F tracking area TA, a S&F registration area RA, or a S&F public land mobile network PLMN; an indication that the first entity is entering the S&F mode; comprising a list of one or more of allowed procedures, disallowed procedures, or restricted procedures for the first entity, the S&F satellite, the S&F eNB, the S&F cell, the S&F TA, the S&F RA, or the S&F PLMN; an indication that the uplink data to be forwarded by the first entity to the second entity is S&F data; or When the first entity is communicatively connected to a third entity, an indication that downlink data of the third entity is to be stored and forwarded, Wherein, the process is one of the following: Tracking area updates; downlink data transmission; Uplink data transmission; RRC connection recovery process; UE context recovery procedure; or RRC connection release process, The second entity is a user equipment UE; Wherein, the controller is configured as follows: receiving an indication from the first entity or from a third entity, the indication indicating that the UE is capable of operating in an S&F network, capable of operating with the first entity, or capable of operating with the satellite, The indication is sent via a non-access stratum (NAS) or in an RRC connection release message.

11. The second entity according to claim 9 or 10, in, The second entity is a UE; Wherein, the controller is configured as follows: During idle mode or inactive mode operation of the UE, lowering the priority of the first entity or a cell of the first entity based on the information about the S&F mode at the first entity; and / or Based on the information about the S&F mode at the first entity, treating the first entity as barred from access by the UE, or The second entity is a mobility management engine MME or a core network CN; and The controller is configured to send one or more UE contexts to the first entity in response to the information, so as to communicate with one or more UEs respectively.

12. The second entity according to claim 9 or 10, in, The controller is configured as follows: performing a UE context recovery procedure with the first entity; and sending downlink data to the first entity; as well as wherein the information indicates that the downlink data will be stored and will be forwarded when the first entity is communicatively connected to the UE, and the information is received during the UE context recovery process, or Wherein, the controller is configured as follows: performing UE context recovery with the first entity; and receiving uplink data from the first entity; and The information indicates that the uplink data is S&F data, and the information is received during the UE context recovery process.

13. A method of a first entity in a non-terrestrial network (NTN), the first entity being configured to operate in a store-and-forward (S&F) mode based on its inclusion in a satellite providing discontinuous coverage, wherein: The method comprises: Information about the S&F mode at the first entity is sent to a second entity.

14. A method for a second entity configured to support a store-and-forward (S&F) mode, the method comprising: receiving, from a first entity in a non-terrestrial network (NTN), information about an S&F mode at the first entity; One or more processes are performed with the first entity based on the information regarding the S&F mode at the first entity.

15. A computer program comprising instructions which, when executed by a computer or a processor, cause the computer or the processor to perform the method according to claim 13 or 14.

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