Apparatus and methods for a satellite for providing non-terrestrial network access, user equipment and methods for performing non-terrestrial network access

Abstract

An apparatus and method of a satellite for providing non-terrestrial network access, a user equipment and method for performing non-terrestrial network access, the apparatus of the satellite comprising: a memory including instructions; at least one processor; at least one transceiver. When the instructions are executed by the at least one processor, the apparatus can be configured to: transmit, to a UE, a message including information associated with an S&F mode, and perform communication with the UE based on the message. The message can contain at least one of information indicating that the satellite supports the S&F mode, information related to a valid time of a service link between the UE and the satellite in the S&F mode, information related to a valid time of a feeder link between the satellite and an NTN gateway in the S&F mode, ephemeris information of the satellite, footprint information provided by the satellite, and information related to a list of neighboring cells supporting the S&F mode.

Description

Technical Field

[0001] This disclosure generally relates to non-terrestrial networks (NTNs) that provide wireless communication services via satellites in Earth orbit or aerial vehicles flying at high altitudes. More specifically, it relates to an apparatus and method for an Internet of Everything (IoT) non-terrestrial network (NTN). Background Technology

[0002] Non-terrestrial networks (NTNs) have been introduced to supplement terrestrial networks providing wireless communication systems. NTNs can provide communication services in areas where terrestrial networks are difficult to establish or in disaster situations. Furthermore, recent reductions in satellite launch costs have made it possible to effectively provide network access environments. Summary of the Invention

[0003] The technical problem to be solved Non-terrestrial networks (NTNs) have been introduced to supplement terrestrial networks providing wireless communication systems. NTNs can provide communication services in areas where terrestrial networks are difficult to establish or in disaster situations. Furthermore, recent reductions in satellite launch costs have made it possible to effectively provide network access environments.

[0004] Technical solutions for solving the problem In embodiments of this disclosure, an apparatus is provided for providing satellite access to a non-terrestrial network (NTN). The apparatus may include: a memory containing instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the apparatus may be configured to: transmit a message to user equipment (UE) including information associated with a store-and-forward (S&F) mode, and to perform communication with the UE based on the message. The message may contain at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of a service link between the UE and the satellite in the S&F mode; information related to the validity period of a feeder link between the satellite and an NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode.

[0005] In embodiments of this disclosure, a user equipment (UE) is provided for performing non-terrestrial network (NTN) access. The UE may include: a memory including instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the UE may be configured to: receive a message from a satellite configured to perform enhanced node B (eNB) functions, including information associated with a store-and-forward (S&F) mode, and to perform communication with the satellite based on the message. The message may contain at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of the service link between the UE and the satellite in the S&F mode; information related to the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode.

[0006] In embodiments of this disclosure, a method is provided performed by a satellite for providing non-terrestrial network (NTN) access. The method may include: transmitting a message to user equipment (UE) including information associated with a store-and-forward (S&F) mode; and performing communication with the UE based on the message. The message may contain at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of a service link between the UE and the satellite in the S&F mode; information related to the validity period of a feeder link between the satellite and an NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode.

[0007] In embodiments of this disclosure, a method is provided performed by a user equipment (UE) for performing non-terrestrial network (NTN) access. The method may include: receiving a message from a satellite configured to perform enhanced node B (eNB) functions, including information associated with a store-and-forward (S&F) mode; and performing communication with the satellite based on the message. The message may contain at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of a service link between the UE and the satellite in the S&F mode; information related to the validity period of a feeder link between the satellite and an NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode. Attached Figure Description

[0008] Figure 1 A wireless communication system is shown.

[0009] Figure 2A and Figure 2B An example of a non-terrestrial network (NTN) is shown.

[0010] Figure 3A An example of a control plane (C-plane) is shown.

[0011] Figure 3BAn example of a user plane (U-plane) is shown.

[0012] Figure 4 An example of the resource structure in the time-frequency domain of a wireless communication system is shown.

[0013] Figure 5 This illustrates an example of the store-and-forward (S&F) mode in a non-terrestrial network (NTN) for the Internet of Everything (IoT).

[0014] Figure 6 This shows the connection status of the satellite and the user equipment (UE) in S&F mode.

[0015] Figure 7 This shows the signaling for pre-actions of the UE in S&F mode.

[0016] Figure 8A This shows an example of the paging process in S&F mode.

[0017] Figure 8B This illustrates an example of discontinuous reception (DRX) in S&F mode.

[0018] Figure 9 Examples of the constituent elements of a UE are shown.

[0019] Figure 10 Examples of the components of a satellite are shown. Detailed Implementation

[0020] The terminology used in this disclosure is for illustrative purposes only and is not intended to limit the scope of other embodiments. Singular expressions include plural expressions unless a different meaning is explicitly indicated in the context. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art as described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of related art, and should not be construed as having an ideal or overly formal meaning unless explicitly defined in this disclosure. Depending on the circumstances, even terms defined in this disclosure should not be construed as excluding embodiments of this disclosure.

[0021] The various embodiments of this disclosure described below are illustrated using hardware-based approach methods. However, since the various embodiments of this disclosure include techniques that use both hardware and software, software-based approach methods are not excluded.

[0022] The terms used in the following description referring to signals (e.g., signal, information, message, signaling), resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), opportunity) (e.g., step, operation, procedure) (e.g., data packet, user stream, information, bit, symbol, codeword) (e.g., data packet, user stream, information, bit, symbol, codeword) (e.g., data packet, user stream, information, symbol, codeword) (e.g., data packet, user stream, information, symbol, codeword) (e.g., data packet, user stream, information, symbol, codeword) (e.g., data packet, user stream, information, information, symbol, codeword) (e.g., data packet, user stream ...

[0023] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, "physical downlink shared channel" (PDSCH) is a term referring to the physical channel through which data is transmitted, but PDSCH can also be used to refer to data. That is, in this disclosure, the expression "transmitting physical channel" can be interpreted as equivalent to the expression "transmitting data or signals through physical channel."

[0024] In the following disclosure, upper-level signaling refers to a signal transmission method in which a base station transmits signals to a terminal using the downlink data channel of the physical layer, or in which a terminal transmits signals to a base station using the uplink data channel of the physical layer. Upper-level signaling can be understood as radio resource control (RRC) signaling or MAC control element (hereinafter referred to as "CE").

[0025] Furthermore, in this disclosure, the expressions "above" or "below" may be used to determine whether a specific condition is satisfied or fulfilled. However, this is merely for illustrative purposes and is not intended to exclude statements of "above" or "below". A condition described as "above" may be replaced by "above", a condition described as "below" may be replaced by "below", and a condition described as "above and below" may be replaced by "above and below". Additionally, "A" to "B" hereafter represent at least one of the elements from A (inclusive) to B (inclusive). "C" and / or "D" hereafter represent at least one of "C" or "D", that is, including {"C", "D", "C and "D"}.

[0026] In this disclosure, signal quality can be, for example, at least one of the following: reference signal received power (RSRP), beam reference signal received power (BRSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal to interference and noise ratio (SINR), carrier to interference and noise ratio (CINR), signal to noise ratio (SNR), error vector magnitude (EVM), bit error rate (BER), and block error rate (BLER). Besides the examples above, other terms or metrics with equivalent technical meanings may be used. Hereinafter, in this disclosure, high signal quality means a large signal quality value associated with signal magnitude or a small signal quality value associated with error rate. Higher signal quality indicates a smoother wireless communication environment. Furthermore, the optimal beam refers to the beam with the highest signal quality among the beams.

[0027] This disclosure uses terminology used in some communication specifications (e.g., the 3rd Generation Partnership Project, 3GPP, and the European Telecommunications Standards Institute, ETSI) to illustrate various embodiments, but this is merely illustrative. The various embodiments of this disclosure can be readily modified and applied in other communication systems.

[0028] Figure 1 A wireless communication system is shown.

[0029] Reference Figure 1 , Figure 1 It is a wireless interface for Radio Access Technology (RAT), and terminal 110 and base station 120 are illustrated as part of a node utilizing a wireless channel in a wireless communication system using the evolved UMTS (Universal Mobile Telecommunications System) radio access network (EUTRAN) or New Radio (NR). Although Figure 1 Only one base station is shown, but the wireless communication system may also include other base stations that are the same as or similar to the base station (e.g., LTE eNB or NR gNB) 120.

[0030] Terminal 110 is a user-operated device that communicates with base station 120 via a wireless channel. In base station 120, the link towards terminal 110 is called the downlink (DL), and the link from terminal 110 towards base station 120 is called the uplink (UL). Furthermore, although not in... Figure 1 As shown, terminal 110 and other terminals can communicate via their respective wireless channels. In this case, the device-to-device (D2D) link between terminal 110 and other terminals is called a sidelink, which can be used interchangeably with the PC5 interface. In other embodiments, terminal 110 can be operated independently of the user. According to one embodiment, terminal 110 is a device performing machine-type communication (MTC) and can be carried by the user. Furthermore, according to one embodiment, terminal 110 can be an NB (narrowband)-IoT (internet of things) device.

[0031] In the process of describing the system and method in this specification, terminal 110 may be an electronic device used to communicate with base station 120 for voice and / or data communication, and base station 120 may communicate with the network of the device (e.g., public switched telephone network (PSTN), Internet, etc.).

[0032] Furthermore, in addition to being called a terminal, the terminal 110 may also be referred to as "user equipment (UE)," "vehicle," "customer premises equipment (CPE)," "mobile station," "subscriber station," "remote terminal," "wireless terminal," "electronic device," "user device," "access terminal," "mobile terminal," "remote station," "user terminal," "subscriber unit," "mobile device," or other terms with equivalent technical meanings.

[0033] Furthermore, examples of terminal 110 include cellular phones, smartphones, personal portable information terminals (e.g., personal digital assistants (PDAs)), laptops, network laptops, e-readers, wireless modems, etc. In the 3GPP specification, terminal 110 is typically referred to as a UE. However, since the scope disclosed in this specification should not be limited by the 3GPP standard, the terms "UE" and "terminal" are used interchangeably in this specification to refer to the more conventional term "wireless communication device." A UE can also be more conventionally referred to as a terminal device.

[0034] Base station 120 is the network infrastructure that provides wireless access to terminal 110. Base station 120 has a coverage area defined based on the distance at which signals can be transmitted. In 3GPP specifications, base station 120 is generally referred to as "Node B", "Enhanced Node B (eNodeB, eNB)", "5th generation node", "Next generation node B (gNB)", "Home Enhanced Node B (HeNB)", or other terms with equivalent technical meanings, such as "access point (AP)", "wireless point", "transmission / reception point (TRP)".

[0035] Because the scope of the disclosures in this specification should not be limited by 3GPP standards, the terms "base station," "node B," "eNB," and "HeNB" are used interchangeably in this specification to refer to the more conventional term "base station." Furthermore, the term "base station" can be used to refer to an access point. An access point can be an electronic device that provides access to a network used for wireless communication equipment (e.g., a local area network (LAN), the Internet, etc.). The term "communication equipment" can be used to refer to both wireless communication equipment and / or a base station. eNB or gNB can also be more conventionally referred to as base station equipment.

[0036] Base station 120 can communicate with core network entity 130. For example, core network entity 130 may include a mobility management entity (MME) responsible for control plane functions such as terminal 110 access and mobility control functions, and a serving gateway (S-GW) responsible for control functions for user data.

[0037] Terminal 110 can perform beamforming with base station 120. Terminal 110 and base station 120 can transmit and receive wireless signals in relatively low frequency bands (e.g., FR 1 in NR). Furthermore, terminal 110 and base station 120 can transmit and receive wireless signals in relatively high frequency bands (e.g., FR 2 in NR (or FR 2-1, FR 2-2, FR 2-3, FR 3), and millimeter-wave (mmWave) bands (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz)). To improve channel gain, terminal 110 and base station 120 can perform beamforming. Here, beamforming can include transmit beamforming and / or receive beamforming. Terminal 110 and base station 120 can impart directivity to the transmitted or received signals. Therefore, terminal 110 and base station 120 can select a serving beam through beam search or beam management steps. After selecting the serving beam, subsequent communication can be performed through resources that have a QCL (Quasi Co-Location) relationship with the resource that transmits the serving beam.

[0038] If the large-scale characteristics of the channel for transmitting symbols at the first antenna port can be inferred from the channel for transmitting symbols at the second antenna port, then the first and second antenna ports can be evaluated as having a QCL relationship. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameter.

[0039] Both terminal 110 and base station 120 can perform beamforming, but the embodiments of this disclosure are not limited thereto. In some embodiments, terminal 110 may or may not perform beamforming. Furthermore, base station 120 may or may not perform beamforming. That is, only one of terminal 110 and base station 120 may perform beamforming, or neither terminal 110 nor base station 120 may perform beamforming.

[0040] In this disclosure, a beam refers to the spatial flow of signals in a wireless channel, formed by one or more antennas (or antenna elements), a process known as beamforming. Beamforming can include at least one of analog beamforming or digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming can include, for example, demodulation-reference signals (DM-RS), channel state information-reference signals (CSI-RS), synchronization signal / physical broadcast channel (SS / PBCH), and sounding reference signals (SRS). Furthermore, as a configuration of each reference signal, information elements (IEs) such as CSI-RS resources or SRS resources can be used, and such configurations can include beam-associated information. Information associated with the beam can indicate whether the corresponding configuration (e.g., CSI-RS resource) uses the same spatial domain filter or a different spatial domain filter from other configurations (e.g., other CSI-RS resources within the same CSI-RS resource set), or which reference signal it is quasi-co-located (QCL), and if so, what type of QCL it is (e.g., QCLtype A, B, C, D).

[0041] In the following description of embodiments, the terminal may be referred to as UE 11, and the base station may be referred to as eNB 120 or gNB 120. In this disclosure, to illustrate the IoT NTN for IoT UEs, eNB 120 is used as an example as the node providing access to the network; however, gNB 120 can be applied in the same or similar manner.

[0042] Figure 2A and Figure 2B An example of a non-terrestrial network (NTN) is shown. Figure 2AThe image shows an example of a non-terrestrial network (NTN) utilizing a transparent satellite. Figure 2B The diagram illustrates an example of a non-terrestrial network (NTN) utilizing a regenerative satellite. NTN refers to an access network that provides non-terrestrial access for a UE (e.g., UE 110) via an NTN payload and NTN gateway mounted on an airborne or space-borne NTN vehicle. This access network can be provided by more than one eNB (e.g., eNB 120).

[0043] Reference Figure 2A NTN200 represents the network environment corresponding to the transparent satellite. NTN200, acting as eNB 120, may include NTN payload 221 and NTN gateway 223. NTN payload 221 is a network node mounted on a satellite or high altitude platform station (HAPS) that provides connectivity between the serving link (described later) and the feeder link (described later). NTN gateway 223 is an earth station configured on the Earth's surface that uses the feeder link to provide connectivity to NTN payload 221. NTN gateway 223 is a transport network layer (TNL) node. NTN 200 can provide non-terrestrial access to UE 110. NTN 200 can provide non-terrestrial access to UE 110 through NTN payload 221 and NTN gateway 223. The link between NTN payload 221 and UE 110 can be referred to as a service link. The link between NTN gateway 223 and NTN payload 221 can be referred to as a feeder link. A feeder link can be compared to a wireless link.

[0044] NTN payload 221 can receive radio protocol data from UE 110 via the serving link. NTN payload 221 can transparently transmit the radio protocol data to NTN gateway 223 via the feeder link. Therefore, NTN payload 221 and NTN gateway 223 can be viewed as an eNB 120 from the perspective of UE 110. NTN payload 221 and NTN gateway 223 can communicate with UE 110 via the Uu interface, which is a general radio protocol interface. That is, NTN payload 221 and NTN gateway 223 can perform radio protocol communication with UE 110 like an eNB 120. NTN gateway 223 can communicate with core network entity 235 (mobility management entity (MME) or serving gateway (S-GW)) via the S1 interface.

[0045] According to one embodiment, the NTN payload 221 and the NTN gateway 223 can utilize the features described later. Figure 3A The wireless protocol stack in the control plane. Furthermore, according to one embodiment, the NTN payload 221 and NTN gateway 223 can utilize... Figure 3B The wireless protocol stack in the user plane.

[0046] exist Figure 2A The description includes an NTN payload 221 and an NTN gateway 223 in eNB 120, but the embodiments of this disclosure are not limited thereto. For example, an eNB may include multiple NTN payloads. Furthermore, for example, the NTN payload may be provided by multiple eNBs. That is, Figure 2A The implementation scenario shown is an example and does not limit the embodiments of this disclosure.

[0047] Reference Figure 2BNTN 250 represents the network environment corresponding to the regenerative satellite. NTN 250 may include satellite 260 operating as eNB 120. Satellite 260 represents a space-borne vehicle carrying a regenerative payload communication transmitter configured in low-earth orbit (LEO), medium-earth orbit (MEO), or geostationary earthorbit (GEO). Satellite 260 may be referred to as a regenerative payload or a regenerative satellite. Satellite 260 represents a payload configured to transform and amplify uplink RF signals before transmitting them to the downlink, the transformation of which may refer to digital processing including demodulation, decoding, re-encoding, re-modulation, and / or filtering. NTN 250 may include an NTN gateway 265 as an entity connected to satellite 260 and configured on land. NTN gateway 265 is an earth station configured on the Earth's surface that provides connectivity to satellite 260 using the feeder link. NTN 250 can provide non-terrestrial access to UE 110. NTN 250 can provide non-terrestrial access to UE 110 via satellite 260 and NTN gateway 265.

[0048] Satellite 260 can be configured to reproduce signals received from terminal 110 or an earth station (e.g., NTN gateway 265). A Uu interface can be defined between satellite 260 and terminal 110. A satellite radio interface (SRI) on a feeder link can be defined between satellite 260 and NTN gateway 265. Although in Figure 2B Not shown, but satellite 260 can provide inter-satellite links (ISL). The ISL is a transmission link between satellites, and can be a radio interface (e.g., X2 or XN interface) or optical interface, defined or not defined by 3GPP. Satellite 260 can communicate with core network entity 235 (e.g., MME or S-GW) via NTN gateway 265 and S1 interface. According to one embodiment, satellite 260 can utilize the following... Figure 3A The wireless protocol stack on the control plane. Furthermore, according to one embodiment, satellite 260 can utilize... Figure 3B The wireless protocol stack on the user plane.

[0049] Although Figure 2BThe present disclosure describes a satellite 260 used for operation of the eNB 120, but embodiments thereof are not limited thereto. An eNB 120 according to embodiments of the present disclosure can be implemented by a distributed deployment utilizing a centralized unit (CU) configured to perform functions of upper layers of the access network (e.g., packet data convergence protocol, radio resource control, RRC) and a distributed unit (DU) configured to perform functions of lower layers. The interface between the CU and the DU may be referred to as an F1 interface. A CU may connect to more than one DU, thereby handling functions at a higher layer than the DU. For example, a CU may handle the functions of the RRC (radio resource control) and PDCP (packet data convergence protocol) layers, while the DU and radio units (RUs) handle lower-layer functions. The DU can be responsible for radio link control (RLC), media access control (MAC), and physical (PHY) layer functions. In such a distributed deployment, Satellite 260 can be used as a CU or DU constituting the eNB-120.

[0050] Figure 3A An example of a control plane (C-plane) is shown. At least part of the following description of eNB 120 can be understood as a description of satellite 260.

[0051] Reference Figure 3A In the C-plane, UE 110 and AMF 235 can execute non-access stratum (NAS) signaling. In the C-plane, UE 110 and eNB 120 can perform communications corresponding to the specified protocols at the RRC, PDCP, RLC, MAC, and PHY layers.

[0052] In NTN access, the main functions of the RRC layer may include at least some of the following functions.

[0053] - Access Stratum (AS) and NAS related system information broadcasting - Paging - This includes setting, maintaining, and disabling the RRC connection between the UE and the access network, and more specifically, control over RLC, MAC, and PHY: - Adding, modifying, and deactivating carrier aggregation - Adding, modifying, and disabling dual connectivity between NR or E-UTRA and NR.

[0054] - Includes security features such as key management; - Configuration, setup, maintenance, management, and deactivation of Signaling Radio Bearer (SRB) and Data Radio Bearer (DRB) - Includes the following mobile features: - Switching and context passing; - UE cell selection and reselection, and cell selection and reselection control; - Mobility between RATs.

[0055] - Quality of service (QoS) management functions; - UE measurement reports and report control; - Radio link failure detection and recovery - Message transmission from / to the UE to / from the NAS to the NAS.

[0056] In NTN access, the main functions of the PDCP layer may include at least some of the following functions.

[0057] - Header compression and decompression function (ROHC only) - User data transfer function - In-sequence delivery of upper layer PDUs - Out-of-sequence delivery of upper layer PDUs - Duplicate detection of lower layer SDUs - Retransmission of PDCP SDUs - Encoding and decoding functions (Ciphering and deciphering) - Timer-based SDU discard in uplink. In NTN access, the main functions of the RLC layer may include at least some of the following functions.

[0058] - Data transfer function (Transfer of upper layer PDUs) - In-sequence delivery of upper layer PDUs - Out-of-sequence delivery of upper layer PDUs - ARQ function (Error Correction through ARQ) - Concatenation, segmentation, and reassembly of RLC SDUs - Re-segmentation of RLC data PDUs - Reordering of RLC data PDUs - Duplicate detection function - Protocol error detection function - RLC SDU discard function - RLC re-establishment function In NTN access, the MAC layer can be connected to multiple RLC layer devices configured in a terminal, and the main functions of the MAC layer can include at least some of the following functions.

[0059] - Mapping between logical channels and transport channels - Multiplexing and demultiplexing of MAC SDUs - Scheduling information reporting function - Error correction through HARQ functionality - Priority handling between logical channels of a UE - Priority handling between UEs by means of dynamic scheduling - MBMS service identification function - Transport format selection function - Padding function In NTN access, entities in the physical layer (e.g., terminal 110, eNB 120) can perform actions such as channel coding and modulation of upper-layer data to create OFDM symbols and transmit them through the wireless channel, or demodulate and decode OFDM symbols received through the wireless channel and transmit them to the upper layer.

[0060] Figure 3B An example of a user plane (U-plane) is shown. At least part of the following description of eNB 120 can be understood as a description of satellite 260.

[0061] Reference Figure 3BIn the U-plane, UE 110 and eNB 120 can perform communication corresponding to the specified protocols at the PDCP layer, RLC layer, MAC layer, and PHY layer, respectively. For details on the PDCP layer, RLC layer, MAC layer, and PHY layer, please refer to the documentation for... Figure 3A Explanation.

[0062] Figure 4 Examples of time-frequency domain resource structures supported by wireless communication systems applicable to embodiments presented in this specification are shown. Although in Figure 4 The resource structure of an LTE network for IoT NTN is described in the examples, but the embodiments of this disclosure are not limited thereto. The signaling and associated actions according to the embodiments of this disclosure can also be applied to NR systems in the same or similar manner.

[0063] Reference Figure 4 The horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest unit of transmission in the time domain is an OFDM symbol, N. symb 402 OFDM symbols converge to form a slot 406 (e.g., 7 slots in an LTE system). See reference. Figure 4 In a wireless communication system to which this invention applies, a radio frame 414 can be defined as consisting of 10 subframes of equal length, each having a length of 1 ms. Furthermore, a radio frame 414 can be divided into half-frames of 5 ms each, with each half-frame comprising 5 subframes. Although in Figure 4 Time slot 406 consists of 7 OFDM symbols, but the length of the time slot can be varied according to the subcarrier spacing. The radio resource supported in the wireless communication system applicable to the invention presented in this specification consists of multiple symbols as time resources and multiple subcarriers as frequency resources, each of which can be represented by a two-dimensional resource grid. Figure 4 In this context, a rectangle representing the smallest physical resource consisting of a subcarrier and a symbol within the resource grid is called a Resource Element (RE).

[0064] In wireless communication systems to which the inventions proposed herein are applicable, the smallest unit of transmission in the frequency domain is a subcarrier, and the carrier bandwidth constituting the resource grid can be N. BW The resource is composed of N subcarriers 404. The basic unit of resources in the time-frequency domain is a resource element (hereinafter referred to as "RE"), which can be represented by an OFDM symbol index and a subcarrier index. A resource block 408 can include multiple resource elements 412. In a wireless communication system to which the invention proposed herein applies, a resource block 408 (or a physical resource block (hereinafter referred to as "PRB")) can be composed of N subcarriers 404 in the time domain. symb Seven (e.g., 7) consecutive OFDM symbols and N in the frequency domain SC RB The data rate is defined as 410 consecutive subcarriers (e.g., 12). The data rate can increase proportionally to the number of RBs scheduled to the terminal. In the case of a frequency division duplex (FDD) system that distinguishes between downlink and uplink frequencies, the downlink and uplink transmission bandwidths may differ. Channel bandwidth represents the radio frequency (RF) bandwidth corresponding to the system's transmission bandwidth. For example, the channel bandwidth can be one of 1.4MHz (e.g., 6 PRB), 3MHz (e.g., 15 PRB), 5MHz (e.g., 25 PRB), 10MHz (e.g., 50 PRB), 15MHz (e.g., 75 PRB), or 20MHz (e.g., 100 PRB).

[0065] E-UTRAN can support radio access via non-terrestrial networks (NTNs) not only for ordinary UEs, but also for BL (bandwidth-limited) UEs, CE (coverage enhancement) UEs, and NB-IoT UEs. Non-terrestrial network support can include platforms providing radio access via geostationary orbit (GSO), non-geostationary orbit (NGSO) (including low Earth orbit (LEO) and medium Earth orbit (MEO)), or high-altitude platform stations (HAPS). In the transparent payload mode, the NTN gateway and the NTN payload (i.e., the satellite) jointly act as the eNB; in the regenerative payload mode, the NTN payload (i.e., the satellite) can act as the eNB.

[0066] Transparent NTN payloads transparently forward radio protocols received by the UE (via the serving link) to the NTN gateway (via the feeder link) and vice versa. Regenerated payloads can terminate connections with the Uu interface (via the serving link), S1, and X2 interfaces. An NTN gateway can support multiple transparent or regenerated NTN payloads. Transparent or regenerated NTN payloads can be served by multiple eNBs. Regenerated NTN payloads can terminate connections with one or more inter-satellite links pointing to other regenerated payloads. As a non-limiting example, transparent NTN payloads can change the carrier frequency before forwarding via the serving link and vice versa (in the feeder link, respectively). In non-terrestrial networks, the tracking area can correspond to a fixed geographical area. In non-terrestrial networks, the same value can be used in the AS (Access Stratum) and NAS (Non-Access Stratum) when the satellite ID refers to the same satellite.

[0067] Three types of service links can be supported in non-terrestrial networks: Earth-fixed: Provided by a beam that continuously covers the same geographical area (e.g., GSO satellite).

[0068] Quasi-Earth-fixed: Provides beam coverage by covering one geographic area for a limited time and another geographic area for other times (e.g., the case of NGSO satellites generating controllable beams).

[0069] Earth-moving: Provided by a beam that moves across the Earth's surface as if gliding over a coverage area (e.g., the case of NGSO satellites generating fixed or uncontrollable beams).

[0070] eNBs using NGSO satellites can provide quasi-ground fixed cell coverage or ground mobile cell coverage, while eNBs using GSO satellites can provide ground fixed cell coverage or quasi-ground fixed cell coverage.

[0071] Store and Forward (S&F) mode can be used to provide communication services to the UE when the serving satellite and terrestrial network have discontinuous connections, and when this connection is unavailable during satellite-UE interaction. The eNB can indicate whether the cell is operating in store and forward mode. Store and forward mode refers to the operating mode that provides communication services to the UE when the serving satellite and NTN gateway have discontinuous connections, and when the connection to the NTN gateway is unavailable during satellite-UE interaction.

[0072] Figure 5 Example 500 illustrates the store-and-forward (S&F) mode in a non-terrestrial network (NTN) for the Internet of Everything (IoT).

[0073] Reference Figure 5 UE 510 can communicate with satellite 520. UE 510 can be referenced as... Figure 1Terminal 110. Satellite 520 can be referenced to base station 120 or a network entity performing at least a portion of the functions of base station 120. According to one embodiment, satellite 520 can be an eNB providing IoT NTN. Satellite 520 can provide E-UTRAN for IoT devices (e.g., UE 510). UE 510 can access satellite 520 in E-UTRAN. The connection between satellite 520 and UE 510 can be referenced to a service link. Satellite 520 can move along a designated orbit. As satellite 520 moves, satellite 520 can connect to a network entity configured on land (hereinafter, the land segment) (e.g., NTN gateway 530). The connection between satellite 520 and NTN gateway 530 can be referenced to a feeder link. NTN gateway 530 can connect to core network 550 via transport network 540. As satellite 520 repeatedly moves along the designated orbit, the service link may become available or unavailable. As satellite 520 moves repeatedly along the specified orbit, the feeder link may become available or unavailable.

[0074] Satellite 520 can support store-and-forward (S&F) mode. S&F mode refers to the operating mode of a system capable of satellite-access. Through S&F mode, delay-tolerant communication services can be provided. When satellite connectivity is intermittently or temporarily unavailable (e.g., providing service to UE 510 located in a coverage area where the feeder link associated with the terrestrial portion (e.g., NTN gateway 530) is not simultaneously activated), a service level of data storage and forwarding can be provided. According to one embodiment, satellite 520 can be used to provide delay-tolerant IoT services via NGSO (non-geostationary satellite orbit) (e.g., LEO (low earth orbit)). According to one embodiment, satellite 520 can provide satellite access to UE 510 that is not equipped with a global navigation satellite system (GNSS) receiver or has limited access to GNSS services. As an unrestricted example, satellite 520 can perform UE-satellite-UE communication with UE 510. For example, to avoid longer latency and limited data rates and reduce resource consumption, UE 510 can also communicate with satellite 520 without communicating with the terrestrial portion (e.g., NTN gateway 530). S&F mode can be used for latency-tolerant and / or interruption-tolerant services. For example, within the 3GPP context, short message service (SMS) can be used for S&F mode, and an end-to-end connection between the endpoints (e.g., UE 510 and the application server) may not be required. Only a connection between the endpoint (e.g., UE 510) and an intermediate node (e.g., short message service center (SMSC)) may be required.

[0075] In S&F mode, the service link between UE 510 and satellite 520 may repeatedly be in an available and unavailable state. An available service link between UE 510 and satellite 520 means that the location of satellite 520 falls within the range of its orbit that can provide service to the area where UE 510 is located (e.g., the footprint) (hereinafter, the available orbit range). An unavailable service link between UE 510 and satellite 520 means that the location of satellite 520 falls within the range of its orbit that makes it difficult to provide service to the area where UE 510 is located (e.g., the footprint) (hereinafter, the unavailable orbit range). In S&F mode, the feeder link between satellite 520 and the terrestrial portion (e.g., NTN gateway 530) may repeatedly be in an available and unavailable state. The service link between satellite 520 and the land segment (e.g., NTN gateway 530) being available means that the position of satellite 520 falls within the range of its orbit that can provide service to the area (e.g., footprint) where the land segment (e.g., NTN gateway 530) is located (hereinafter, the available feeder orbit range). The service link between satellite 520 and the land segment (e.g., NTN gateway 530) being unavailable means that the position of satellite 520 falls within the range of its orbit that makes it difficult to provide service to the area (e.g., footprint) where the land segment (e.g., NTN gateway 530) is located (hereinafter, the unavailable feeder orbit range). For UE510, the availability of the service link and the availability of the feeder link may not always occur simultaneously. For example, even if the status of the service link changes from available to unavailable, it does not necessarily mean that the status of the feeder link changes.

[0076] According to one embodiment, UE 510 can transmit signals. These signals may be mobile-originating (MO) data. For example, in action 591, when the serving link is available, UE 510 can transmit uplink data (e.g., PUSCH) to satellite 520. Satellite 520 can receive the uplink data from UE 510. Since the feeder link is unavailable, satellite 520 can store the uplink data. Subsequently, satellite 520 can move. With this movement, the feeder link's state may change from available to unavailable. In action 592, satellite 520 can transmit the uplink data via a network entity configured on land (e.g., NTN gateway 530). The uplink data can be transmitted to the data network via core network 550. Hereinafter, in S&F mode, the service of transmitting messages sent by UE 510 via satellite 520 can be referred to as MO service.

[0077] According to one embodiment, satellite 520 can transmit signals to UE 510. These signals may be mobile terminated (MT) data. For example, in action 593, while the feeder link is available, satellite 520 can receive data from external devices (e.g., servers, other UEs) via the data network and core network 550 (e.g., UPF). Satellite 520 can move. As satellite 520 moves, the state of the feeder link may change from available to unavailable. As satellite 520 moves, the state of the service link between satellite 520 and UE 510 may change from unavailable to available. In action 594, when the service link is available, satellite 520 can transmit downlink data (e.g., PDSCH) to UE 510. Hereinafter, the service of messages transmitted in UE 510 via satellite 520 in S&F mode can be referred to as MT service.

[0078] According to embodiments of this disclosure, a network (e.g., an eNB) can indicate store-and-forward (S&F) mode to a terminal (e.g., a UE) via an SIB1 message. For example, the "sf-OperationMode" IE can be included in the SIB1 message. This IE can indicate that the cell is operating in store-and-forward mode. When this field is present, a UE supporting store-and-forward operations can ignore cellBarred-NTN and cellBarred. The IE can point to either a "barred" or "notBarred" value. The value "barred" indicates that the cell has been barred for NTN connections via store-and-forward operations as defined in TS 36.304. The value "notBarred" indicates that the cell allows access for UEs supporting store-and-forward operations. If this field is not present, the SIB1 message can indicate that the NTN cell is operating in general mode, i.e., non-store-and-forward mode.

[0079] According to embodiments of this disclosure, a network (e.g., an eNB) can indicate time information related to the store-and-forward mode to a terminal (e.g., a UE) via SIB31. SIB31 may contain satellite assistance information about the serving cell. As said satellite assistance information, ephemeris information, satellite ID, and information about the reference location may be included in SIB31. According to one embodiment, the SIB31 message may contain switching time information (e.g., t-ModeSwitching IE). If SIB31 contains... sf-OperationMode If the NTN cell switches from store-and-forward operation mode to normal mode, then this field indicates the time information. Otherwise, this field indicates the time information of the NTN cell switching from normal mode to store-and-forward mode.

[0080] Figure 6 This shows the connection status of the satellite (e.g., satellite 520) and the user equipment (UE) in S&F mode. Figure 6 To illustrate various examples depending on the region where the UE is located, the description uses the first UE 511, the second UE 512, and the third UE 513 as examples. Furthermore, for each UE, reference can be made to the specific examples provided. Figure 5 Description of UE 510.

[0081] Reference Figure 6Satellite 520 can move. As satellite 520 moves, the feeder link between satellite 520 and the land segment (e.g., NTN gateway 530) may repeatedly be in an available or unavailable state. For example, in the first time segment 621, the feeder link of satellite 520 may be unavailable. Satellite 520 can operate without the feeder link. For example, in the second time segment 622, the feeder link of satellite 520 may be available. Satellite 520 can operate with the feeder link. For example, in the third time segment 623, the feeder link of satellite 520 may be unavailable. Satellite 520 can operate without the feeder link. Depending on whether the feeder link of satellite 520 is available or unavailable, the operation of UEs in the RRC idle state (e.g., first UE 511, second UE 512, third UE 513) may change. For example, before the first UE 511 reaches coverage state 631, satellite 520 may not have the opportunity to access the terrestrial portion (e.g., NTN gateway 530). In such a case, the first UE 511 may not perform paging monitoring. The first UE 511 may skip monitoring for paging messages from satellite 520. For example, before the second UE 512 reaches coverage state 632, satellite 520 may pre-access the terrestrial portion (e.g., NTN gateway 530). In such a case, even if satellite 520 is in S&F mode, the second UE 512 may still perform monitoring for paging messages from satellite 520. For example, while the feeder link of satellite 520 is available, the third UE 513 may be available. The third UE 513 may perform normal actions (e.g., paging monitoring regardless of satellite access status).

[0082] In the RRC idle state, the actions of the UE (e.g., UE 511, UE 512, and UE 513) can be determined based on the current feeder link status and the past feeder link status during the period when the UE was out of coverage (i.e., out-of-coverage). For example, if the feeder link is temporarily restored by satellite 520, the UE (e.g., UE 511, UE 512, and UE 513) can monitor paging messages and perform data reception. If satellite 520 does not have the opportunity to restore the feeder link, the UE can skip paging message monitoring. The following is explained through... Figure 7 , Figure 8A and Figure 8BThis section describes in detail the UE actions in the RRC idle state corresponding to the current feeder link state and past feeder link states. When satellite 520 is in S&F mode, MO data transmission can be performed on UEs in the RRC idle state (e.g., UE 511, UE 512, and UE 513). When satellite 520 is in S&F mode, UEs in the RRC idle state (e.g., UE 511, UE 512, and UE 513) can perform initial network access and data transmission (e.g., in cases consisting of early data transmission (EDT) / cellular IoT (CIoT) operations).

[0083] Figure 7 This illustrates the signaling for pre-actions of a UE (e.g., UE 510) in S&F mode. Satellite 520 can be configured to perform the functions of an eNB. As an example, the eNB can be configured on the payload of satellite 520, while an entity of the core network (e.g., core network 550) is configured on land. As an example, the eNB and a portion of the core network entity (or, a portion of a specific entity (e.g., MME (mobile management entity)) can be configured on the payload of satellite 520, while another portion of the core network entity is configured on land.

[0084] Reference Figure 7 In action 701, satellite 520 can transmit information related to feeder link restoration to UE 510. For example, when assumed to be... Figure 6 When the second UE 512 is active, the service link between the second UE 512 and the satellite 520 remains active even if the feeder link of the satellite 520 is unavailable. Because the service link is active, the second UE 512 can perform the actions required in the RRC idle state. Since the second UE 512 anticipates the restoration of the feeder link, it can perform the actions required in the RRC idle state (e.g., paging monitoring, DRX). For the actions of the second UE 512 in the RRC idle state, the satellite 520 can provide the second UE 512 with information related to the restoration of the feeder link.

[0085] 1. Signaling Information associated with feeder link recovery can be provided in various signaling formats. According to one embodiment, the information associated with feeder link recovery can be provided via a system information block (SIB). For example, the information associated with feeder link recovery can be provided via SIB 31 or SIB 32. Hereinafter, this disclosure describes SIB 32 as an example, but it is not excluded that the information described below can be transmitted via SIB 31 or other SIBs. SIB 32 may include satellite-aided information for predicting discontinuous coverage. SIB 32 can be signaled over NTN cells provided by satellite 520. The information associated with the feeder link recovery can be cell-specific information.

[0086] As an example, SIB 32 can be referenced from the following table.

[0087] Table 1

[0088] "carrierFreqList" represents a list of E-UTRA frequencies. "elevationAngleLeft" and "elevationAngleRight" represent the elevation angles on the left and right sides (referencing the satellite's orientation), respectively, in degrees. Actual values ​​can be the corresponding threshold multiplied by 5. "footprintInfo" represents the satellite's footprint. Satellite 520 (e.g., E-UTRAN) can construct elevation angles and / or radii for earth-moving cells. Satellite 520 (e.g., E-UTRAN) can construct reference points and radii for quasi-earth fixed cells. "latitude" represents the latitude of the reference point (in degrees). "longitude" represents the longitude of the reference point (in degrees). "satelliteInfoList" represents a list of satellite information. "serviceInfo" represents coverage information provided by the satellite. "t-EphemerisParameters" represents the average value of satellite orbital parameters in TLE set form used to track the period within and outside the coverage area of ​​satellites including Earth mobile cells (e.g., satellite 520). "t-ServiceStart" represents time information related to the time point when a receiving satellite for a quasi-earth fixed cell begins providing service to the corresponding area. "feederlinkinfo" represents information associated with feeder link recovery according to embodiments of this disclosure. In addition to the above description, reference may be made to the specification TS 36.331 v18.3.1 for each IE.

[0089] According to another embodiment, the information associated with feeder link recovery can be provided through an RRC message (e.g., an RRC reconfiguration message) that is different from system information. For example, the information associated with feeder link recovery can be UE-specific information. According to yet another embodiment, the information associated with feeder link recovery can be provided through a medium access control (MAC) control element (CE). According to yet another embodiment, the information associated with feeder link recovery can be provided through downlink control information (DCI).

[0090] 2. Parameters The information associated with feeder link recovery may include more than one parameter. This information may be used to provide the UE (e.g., UE 510) receiving the information with information related to the recovery of the satellite (e.g., satellite 520) used to provide the NTN cell. Therefore, the information associated with feeder link recovery may include information indicating the recovery time of satellite 520 and / or information required to anticipate the recovery time.

[0091] According to one embodiment, the information associated with feeder link recovery may include timer-related information. For example, the timer-related information may indicate the length of the timer and / or the start time of the timer. UE 510 may start the timer. For example, UE 510 may start the timer in response to receiving the timer-related information. As another example, UE 510 may start the timer at the start time indicated by the timer-related information. When the timer is running, UE 510 may recognize that the feeder link of satellite 520 is in a recoverable state. The termination of the timer may indicate the recovery of the feeder link of satellite 520. During the period when the timer is running, UE 510 may expect that although the feeder link of satellite 520 is unavailable, it will be restored at the same time as the timer terminates. When an indicator indicating that the feeder link of satellite 520 is available or an indicator indicating that the feeder link of satellite 520 will not be restored is received, UE 510 may stop running the timer. For example, UE 510 can activate a timer received from satellite 520. UE 510 can then start the timer. As satellite 520 is located near a land segment (e.g., NTN gateway 530), the feeder link can be available. Alternatively, the service link between UE 510 and satellite 520 can be unavailable. With the timer terminated, UE 510 can recognize that the feeder link of satellite 520 is available. Satellite 520 can then move along its orbit again. The feeder link can become unavailable. Satellite 520 can then reconnect to UE 510 via signaling. When UE 510 reaches access to satellite 520, the timer can be restarted. Subsequently, during the timer's operation, UE 510 can determine that the feeder link is unavailable. Additionally, while UE 510 is accessing satellite 520, satellite 520 can provide UE 510 with information related to the changed feeder link status. For example, if satellite 520 needs to change the value of the timer or if it is difficult to run the timer again (e.g., if it is not likely that the feeder link will be restored in a short period of time), it can provide an additional indicator to UE 510. UE 510, which receives the indicator, can stop or release the timer.

[0092] According to one embodiment, the information associated with feeder link recovery may include history-related information. This information can provide history-related information about connections made by satellite 520 to the land segment (e.g., NTN gateway 530) during its orbit. For example, the information associated with feeder link recovery may include information related to packet data unit (PDU) sessions or evolved packet system (EPS) bearers associated with the cell of satellite 520. UE 510 can determine the likelihood of recovery based on the PDU sessions or EPS bearers associated with the cell provided by satellite 520. For example, if the type of service represented by the PDU session or EPS bearer is a delay-tolerant service, UE 510 can identify that the feeder link of satellite 520 will be restored within a predefined time. As an example, UE 510 confirms the Quality of Service Class Identifier (QCI). If the QCI is a pre-specified value (e.g., a value indicating latency-tolerant service or a guaranteed bit rate (GBR) below a threshold), UE 510 can identify that the feeder link of satellite 520 will recover within a predefined time. UE 510 can obtain time information associated with the feeder link ID. UE 510 can anticipate the recovery time of the feeder link of satellite 520. For example, the information associated with feeder link recovery may include information related to the IDs of feeder links that satellite 520's cell has connected to the core network (e.g., core network 550). UE 510 can obtain time information associated with the feeder link ID. UE 510 can anticipate the recovery time of the feeder link of satellite 520. For example, the information associated with feeder link recovery may include the satellite ID or the ID of a core network entity configured on land. As an example, the core network entity ID may include the MME ID. UE 510 can predict the recovery time of the feeder link of satellite 520 based on the geographical area where the MME ID is located and / or cell information (e.g., ephemeris information, orbit information) associated with satellite 520.

[0093] According to one embodiment, the information associated with feeder link recovery may include space-related information. For example, the information associated with feeder link recovery is historical information related to satellite 520, which may include tracking area, location area, footprint information, service information, and / or ephemeris information.

[0094] In action 703, satellite 520 can transmit more than one parameter for S&F mode to UE 510. According to one embodiment, UE 510 can perform a paging step corresponding to S&F mode in RRC idle state. A description of the paging step and the parameters associated with it will be provided later. Figure 8A A detailed description will follow. According to one embodiment, UE 510 can execute DRX actions corresponding to S&F mode. A description of the DRX actions and the parameters associated with them will be provided later. Figure 8B A detailed description is provided. Although illustrated in this disclosure, parameters for UE 510 in RRC idle state are provided separately with signaling information associated with feeder link recovery in S&F mode, embodiments of this disclosure are not limited thereto. For example, parameters in action 703 may be transmitted together with information associated with feeder link recovery in action 701. As an example, satellite 520 may transmit information associated with feeder link recovery and parameters for UE in RRC idle state (e.g., parameters associated with the paging step, parameters associated with the DRX action) to UE 510 via a single message (e.g., system information such as SIB 32, an RRC message such as an RRC reconfiguration message).

[0095] In action 705, UE 510 can anticipate the recovery time point. In other words, UE 510 can determine the anticipated recovery time point. According to one embodiment, UE 510 can determine the recovery time point of the feeder link of satellite 520 based on information associated with feeder link recovery from satellite 520. According to one embodiment, UE 510 can determine the recovery time point of the feeder link of satellite 520 based on information associated with feeder link recovery from satellite 520 and parameters associated with the DRX action. For example, UE 510 can determine that the feeder link of satellite 520 will be restored after a specified time following the DRX activation period associated with the cell of satellite 520. The specified time can be indicated by satellite 520 or calculated in a predefined manner using DRX parameters (e.g., an area determined to be after 50% in a Long DRX cycle). According to one embodiment, UE 510 can determine the recovery time point of the feeder link of satellite 520 based on information associated with feeder link recovery from satellite 520 and parameters associated with the paging step. For example, UE 510 can determine that after receiving a paging frame associated with the cell of satellite 520, the feeder link of satellite 520 will be restored after a specified time has elapsed since the paging frame. The specified time can be indicated by satellite 520 or calculated in a predefined manner using paging parameters (e.g., 40% to 60% of the paging cycle).

[0096] In action 707, UE 510 can perform a pre-action. The pre-action refers to an action that UE 510 anticipates and pre-executes in anticipation of feeder link restoration. UE 510 can be in an RRC idle state.

[0097] When the recovery time point is anticipated via action 705, UE 510 can perform a pre-action. According to one embodiment, if the termination time of the serving link is within a first critical interval from the current time point, and the recovery time point of the feeder link is within a second critical interval from the current time point, UE 510 can additionally perform paging monitoring. By performing paging monitoring, UE 510 can increase paging opportunities to attempt access as much as possible before the serving link terminates. As a non-limiting example, even if the termination time of the serving link is within the first critical interval from the current time point, or the recovery time point of the feeder link is within the second critical interval from the current time point, UE 510 can still perform additional paging monitoring. According to one embodiment, if the termination time of the serving link is within the first critical interval from the current time point, and the recovery time point of the feeder link is within the second critical interval from the current time point, UE 510 can set a shorter paging monitoring period. The shorter the paging monitoring period, the more paging monitoring can be performed per unit time period. As an unrestricted example, even if the termination time of the service link is within the first critical interval from the current time, or the recovery time of the feeder link is within the second critical interval from the current time, the UE 510 can set a shorter paging monitoring cycle than the basic cycle.

[0098] According to one embodiment, the first critical interval and / or the second critical interval may be indicated by the network (e.g., satellite 520) (e.g., RRC message, MAC CE, DCI), or determined based on the ephemeris information of satellite 520, or determined as a fixed value.

[0099] UE 510 can perform monitoring of paging messages from satellite 520 in RRC idle state. Parameters associated with the paging message and / or parameters associated with the monitoring can be configured in UE 510 by satellite 520. Anticipating that the feeder link of satellite 520 will be restored, UE 510 can attempt cell access to perform services available via the feeder link of satellite 520 (e.g., delay-tolerant service, SMS service). UE 510 can perform a random access procedure with satellite 520 in response to receiving the paging message. After the random access procedure, UE 510 can operate in RRC connected state. UE 510 can send or receive data with satellite 520. For example, UE 510 can provide uplink data (e.g., PUSCH) to satellite 520. Satellite 520 can store the uplink data. Subsequently, when the feeder link is restored, the uplink data can be transmitted to other devices (e.g., servers, smartphones) via the feeder link and core network entities.

[0100] According to one embodiment, if the termination time of the service link is within a first critical interval from the current time point, and the recovery time of the feeder link is within a second critical interval from the current time point, UE 510 can set an additional activation period. Through this additional activation period, UE 510 can transmit more data to satellite 520. The information associated with the additional activation period is the length of a timer or period, which can be provided from satellite 520. For example, the information associated with the additional activation period can be received from SIB or RRC messages of satellite 520. For example, the information associated with the additional activation period can be included in action 701 related to feeder link recovery and / or in action 703 for S&F mode, or more than one parameter. For example, UE 510 can perform a DRX step with satellite 520. The parameters associated with the DRX step can be configured in UE 510 by satellite 520. UE 510 can perform a DRX action after accessing the satellite. DRX stands for Discontinuous Receive, which means repeatedly executing active and inactive periods for power saving in UE 510. Since UE 510 is more advantageous in transmitting data considering the feeder link recovery time, it can determine whether to skip data transmission / reception during the DRX active period based on the feeder link recovery time. As a non-limiting example, even if the service link termination time is within the first critical interval from the current time, or the feeder link recovery time is within the second critical interval from the current time, UE 510 can still communicate with the network through an additionally set active period.

[0101] According to one embodiment, when the feeder link recovery time is anticipated, UE 510 can increase the access priority associated with the NTN cell. As an example, it can increase the cell-related priority information (e.g., "CellReselectionPriority" (e.g., refer to TS 36.304, TS 36.331)) or decrease the cell reselection threshold (e.g., ReselectionThreshold IE). According to one embodiment, when the feeder link recovery time is anticipated and the feeder link is anticipated to recover within a specified time, UE 510 can perform a conditional handover. For example, the handover execution conditions can be set based on parameters associated with the feeder link recovery time. As an unrestricted example, UE 510 can select one of more than one cells indicated in the "whitelist Cell List" IE and perform a handover to the selected cell (e.g., conditional handover).

[0102] Figure 8A Example 800 of a paging procedure in S&F mode is shown. Satellite 520 can be configured to perform the functions of an eNB. As an example, the eNB can be configured on the payload of satellite 520, with the entity of the core network (e.g., core network 550) configured on land. As an example, the eNB and a portion of the core network entity (or, a portion of a specific entity (e.g., MME (mobile management entity))) can be configured on the payload of satellite 520, with another portion of the core network entity configured on land. The same reference numerals can indicate applicable descriptions.

[0103] Reference Figure 8AIn RRC idle state, UE 510 can utilize DRX (discontinuous reception) to save power. A paging occasion (PO) represents a subframe that P-RNTI can transmit via the physical downlink control channel (PDCCH) used for processing paging messages. A paging frame (PF) represents a radio frame and can include more than one paging occasion. When using DRX, UE 510 can monitor only one paging occasion in each DRX cycle (e.g., DRX cycle 810). For example, a radio frame within DRX cycle 810 (e.g., frame 821) can be a paging frame. For example, the paging frame for UE 510 can be frame 822. Frame 822 for UE 510 is a paging frame that includes multiple paging occasions (e.g., paging occasion 831), and the paging occasion for UE 510 can be paging occasion 832. When conforming to 3GPP specifications, the paging frame can be determined based on the following mathematical formula.

[0104] Mathematical Formula 1 SFN mod T= (T div N)*(UE_ID mod N) Here, T represents the DRX period (e.g., DRX period 810), and N represents the smaller of T and nB (i.e., min(T, nB)), where nB can be constructed from RRC. UE_ID is a module of the International Mobile Subscriber Identity (IMSI) value, representing the result of a 1024 operation (UE_ID: IMSI mod 1024).

[0105] When conforming to the 3GPP specification, the pattern of paging timing within a subframe can be determined based on the following mathematical formula.

[0106] Mathematical formula 2 i_s = floor(UE_ID / N) mod Ns Here, Ns represents max(1, nB / T).

[0107] According to various embodiments of this disclosure, UE 510 can receive one or more parameters for a paging step from satellite 520. According to one embodiment, the one or more parameters for the paging step may include information related to the paging cycle for S&F mode. The paging cycle may be used to specifically specify the DRX cycle of UE 510 operating in S&F mode. As an example, the paging cycle may refer to the "T" value of [Mathematical Formula 1]. By using a shorter cycle, UE 510 can perform paging monitoring. As an unlimited example, additional paging for S&F mode can be added to existing paging steps and executed in preparation. As an example, when operating in S&F mode, if a service link unavailability is anticipated (e.g., the time from when the service link becomes unavailable is before a specified time), UE 510 can execute an additional paging step. The information related to the specified time may be set from the network or be a fixed value. As an example, when operating in S&F mode, if the restoration of the service link is anticipated (e.g., the time from when the service link becomes available is before a specified time), UE 510 can perform an additional paging step. The information related to the specified time can be set from the network or is a fixed value. The paging period can represent the DRX period, which includes the anticipated time of unavailability or recovery.

[0108] According to one embodiment, the one or more parameters used in the paging step may include information related to the paging timing for S&F mode. For example, the information related to the paging timing may include an "nB" value. As another example, the information related to the paging timing may include parameters (e.g., offset, timing number) indicating the paging timing for performing an additional paging. As an unrestricted example, an additional paging for S&F mode may be added to an existing paging step and executed in preparation. As an example, when operating in S&F mode, if the service link is anticipated to be unavailable (e.g., the time when the service link becomes unavailable is before a specified time), UE 510 may perform the additional paging step. As an example, when operating in S&F mode, if the service link is anticipated to be restored (e.g., the time when the service link becomes available is before a specified time), UE 510 may perform the additional paging step. UE 510 can perform paging monitoring at a paging time indicated by information related to the paging time.

[0109] According to one embodiment, the one or more parameters used in the paging step may include information related to an identifier. The identifier may be used to identify the paging message for a satellite 520 supporting S&F mode. For example, the identifier-related information may include a P-RNTI for S&F mode. For example, the identifier-related information may include an identifier for S&F mode different from the P-RNTI. As a non-limiting example, additional paging for S&F mode may be added to an existing paging step and executed in advance. As an example, when operating in S&F mode, if the unavailability of the serving link is anticipated (e.g., the time from when the serving link becomes unavailable is before a specified time), UE 510 may perform an access attempt using a PDCCH masked by the identifier. As another example, when operating in S&F mode, if the recovery of the serving link is anticipated (e.g., the time from when the serving link becomes available is before a specified time), UE 510 may perform an access attempt using a PDCCH masked by the identifier.

[0110] According to one embodiment, the one or more parameters used in the paging step may include information related to the number of paging monitoring sessions. As satellite 520 moves, the service link between UE 510 and satellite 520 may become ineffective in S&F mode. In this ineffective state, to avoid UE 510 unnecessarily monitoring paging messages from satellite 520, the number of paging monitoring sessions (e.g., the number of paging opportunities) can be set. After monitoring according to the number of paging monitoring sessions used for S&F, UE 510 may maintain an RRC IDLE state for a predefined time (e.g., the orbital period of satellite 520 – offset time). The offset time may represent the time that satellite 520 is connected to UE 510 in S&F mode. The predefined time can be determined by UE 510 or set by the network (e.g., satellite 520). Subsequently, after the predefined time, the UE 510 can perform paging monitoring again due to the anticipated restoration of the service link.

[0111] According to one embodiment, the one or more parameters used for the paging step may include information related to the number of pre-paging monitoring sessions. Under S&F mode, the service link between UE 510 and satellite 520 may repeatedly become restored and unavailable. UE 510 may additionally perform paging monitoring from a predetermined time point before the service link is restored. To avoid delaying the reopening time of communication between UE 510 and satellite 520 due to paging cycles, UE 510 may additionally perform a pre-paging step. The pre-paging step may be performed at the beginning of each paging cycle, and within the corresponding paging cycle, in addition to the paging timing corresponding to predefined parameters, it may also indicate the number of additional paging timings to be performed.

[0112] Figure 8B Example 840 illustrates discontinuous reception (DRX) operation in S&F mode. Satellite 520 can be configured to perform the functions of an eNB. As an example, the eNB can be configured on the payload of satellite 520, with the entity of the core network (e.g., core network 550) configured on land. As an example, the eNB and a portion of the core network entity (or, a portion of a specific entity (e.g., MME (mobile management entity))) can be configured on the payload of satellite 520, with another portion of the core network entity configured on land. The same reference numerals can indicate applicable descriptions.

[0113] Reference Figure 8BIn the RRC idle state, UE 510 can utilize DRX (discontinuous reception) to save power. To reduce battery consumption, UE 510 can periodically switch between active and inactive states. In the active state (i.e., on-duration), UE 510 receives or transmits data to or from the network (e.g., satellite 520), while in the inactive state, power is saved by minimizing standby time. For example, in the active state, UE 510 can turn on the RF unit, and in the inactive state, UE 510 can turn off the RF unit. UE 510 can send or receive data packets in the active state 851 of the RRC connected state (RRC_connected). UE 510 can start an inactive timer each time a data packet is sent or received. When the inactive timer expires, UE 510 can enter the DRX mode 852 of the RRC connected state (RRC_connected). UE 510 can be activated and perform communication in each short DRX cycle. The interval during which UE 510 transmits or receives signals can be considered as the active period. When the DRX short-cycle timer terminates, the DRX repetition cycle (the cycle of changing between active and inactive states) of UE 510 can change from a short DRX cycle to a long DRX cycle. In the active state corresponding to the DRX cycle, when UE 510 receives data (e.g., decoding PDCCH), UE 510 can terminate the DRX mode and act again in the active state 853 of the RRC connected state (RRC_connected). In the DRX mode or active state 853 of the RRC connected state, when there is no data transmission or reception interval, UE 510 can enter the RRC idle state (RRC_idle) 854. Even in the RRC idle state 854, UE 510 can perform DRX actions. The DRX actions in the RRC idle state 854 can be considered as... Figure 8A Example of paging monitoring steps.

[0114] According to various embodiments of this disclosure, UE 510 can receive one or more parameters for DRX from satellite 520. According to one embodiment, the one or more parameters for DRX may include information related to the on-duration of the S&F mode. For example, the information related to the on-duration may represent a time segment within the DRX cycle corresponding to the active state. The information related to the on-duration may include a value corresponding to the number of subframes. As an example, when the restoration of the service link is anticipated, it is advantageous to extend the active state time; therefore, the information related to the on-duration of the S&F mode may be set to a longer value than the typical (i.e., configured for communication between the terrestrial base station and the UE) DRX on-duration. As another example, after the service link terminates, since it is not necessary to operate in an active state, the information related to the on-duration of the S&F mode may be set to a longer value than the typical (i.e., configured for communication between the terrestrial base station and the UE) DRX on-duration. The parameter is an activation period separately set for S&F mode. When the service link is nearing termination (e.g., within the first critical period) or recovery time, sufficient activation can be ensured through the corresponding activation period. This can improve the effective activation time for UE 510 to communicate with satellite 520 in S&F mode. As a non-limiting example, instead of setting the activation period separately from the general DRX activation period, the activation period can be added to the general DRX activation period to additionally configure the time for maintaining the activation state in UE 510 and used as a parameter for DRX.

[0115] According to one embodiment, the one or more parameters used for DRX may include information related to the DRX inactivity timer used for S&F mode. From the perspective of UE 510 operating in S&F mode, it is advantageous to maintain the active state as much as possible to improve data transmission efficiency before the service link is terminated. Furthermore, from the perspective of UE 510, maintaining the active state from the time the service link is restored is advantageous in terms of transmission efficiency. This is because UE 510 will not need to use the RF unit anyway when the service link is unavailable. The information related to the DRX inactivity timer used for S&F mode can be set to a longer value than a typical DRX inactivity timer (i.e., one configured for communication between the terrestrial base station and the UE). The parameter is a timer separately set for S&F mode, which, by delaying the time of entering DRX mode as much as possible when the service link termination time is approaching (e.g., within the first critical period), can sufficiently ensure the active state of UE 510. As an unrestricted example, instead of setting a general DRX inactivity timer separately, it can also be added to the general DRX inactivity timer and additionally configured in UE 510 to maintain the active state offset, and used as a parameter for DRX.

[0116] According to one embodiment, the one or more parameters used for the DRX may include information related to the DRX cycle length for the S&F mode. A longer DRX cycle length is more advantageous in terms of battery saving for the UE 510. On the other hand, a shorter DRX cycle length is more advantageous in terms of transmission efficiency because the UE 510 enters the active state at rapid intervals. For example, from the perspective of the UE 510 operating in S&F mode, it is advantageous to improve data transmission efficiency by increasing the frequency of the active state when the restoration of the service link is anticipated. For example, from the perspective of the UE 510, maintaining the active state from before the service link is restored is more advantageous in terms of transmission efficiency. The information related to the DRX cycle length for the S&F mode can be set to a shorter value than the typical (i.e., the DRX cycle length configured for communication between the terrestrial base station and the UE) DRX cycle length. As an unrestricted example, instead of setting the DRX cycle length separately from the normal DRX cycle length, an offset can be additionally configured in UE 510 compared to the normal DRX cycle length and used as a parameter for DRX.

[0117] According to one embodiment, the one or more parameters used for the DRX may include information related to the DRX short-cycle timer used for the S&F mode. From the perspective of the UE 510 operating in S&F mode, it is advantageous to maintain the active state as much as possible to improve data transmission efficiency before the serving link is terminated. This is because the UE 510 will not need to use the RF unit anyway when the serving link is unavailable. However, the DRX short-cycle timer is used to enter the DRX long cycle, which is more advantageous in terms of transmission efficiency when the serving link is unavailable. The information related to the DRX short-cycle timer used for the S&F mode can be set to a longer value than the general (i.e., the DRX short-cycle timer configured for communication between the terrestrial base station and the UE) DRX short-cycle timer. The parameter is a timer separately set for S&F mode, which can sufficiently ensure the active state of the UE 510 by delaying the time of entering the DRX long cycle as much as possible when the termination time of the serving link is approaching (e.g., within the first critical period). As an undefined example, instead of the general DRX short-cycle timer being set separately, it can also be added to the general DRX short-cycle timer and additionally configured in UE 510 to maintain the active state offset, and used as a parameter for DRX.

[0118] According to one embodiment, the one or more parameters used for DRX may include information indicating whether DRX is supported in the S&F mode. For example, whether DRX support for S&F mode is supported can be configured as separate information in the UE 510. The DRX configuration information may include information related to DRX for S&F mode. When the information related to DRX for S&F mode indicates enable, the parameters for S&F mode can be configured separately in the UE 510 from the general (i.e., those configured for communication between the terrestrial base station and the UE) DRX parameters. When the information related to DRX for S&F mode indicates disable, the UE 510 can reuse the general DRX parameters for S&F mode.

[0119] Figure 9 Examples of the constituent elements of a UE (e.g., UE 510) are shown.

[0120] Reference Figure 9UE 510 may include a transceiver 901, a processor 903, and a memory 905. The transceiver 901 performs functions for transmitting and receiving signals via a wireless channel. For example, the transceiver 901 uplinks baseband signals to RF band signals and transmits them through an antenna, and downlinks RF band signals received through the antenna back to baseband signals. For example, the transceiver 901 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC (digital-to-analog converter), an ADC (analog-to-digital converter), etc.

[0121] Transceiver 901 may include multiple transmit / receive paths. Further, transceiver 901 may include an antenna section. Transceiver 901 may include at least one antenna array composed of multiple antenna elements. From a hardware perspective, transceiver 901 may be composed of digital circuitry and analog circuitry (e.g., radio frequency integrated circuit (RFIC)). Here, the digital and analog circuitry may be implemented in a single package. Furthermore, transceiver 901 may include multiple RF chains. Transceiver 901 may perform beamforming. To impart directionality to the signals to be transmitted and received corresponding to the settings of processor 903, transceiver 901 may apply beamforming weights to the signals. According to one embodiment, transceiver 901 may include an RF (radio frequency) block (or RF section). According to one embodiment, transceiver 901 may support satellite communication. UE 510 can transmit signals to or receive signals from a satellite (e.g., satellite 520) via transceiver 901.

[0122] Transceiver 901 can transmit and receive signals on a radio access network. For example, transceiver 901 can receive downlink signals. Downlink signals may include synchronization signals (SS), reference signals (RS) (e.g., cell-specific reference signal (CRS), demodulation reference signal (DM(demodulation)-RS)), system information (e.g., MIB, SIB, remaining system information (RMSI), other system information (OSI)), configuration messages, control information, or downlink data, etc. Furthermore, transceiver 901 can also transmit uplink signals, for example. The uplink signals may include random access association signals (e.g., random access preamble (RAP) (or message 1, Msg1), message 3, Msg3), reference signals (e.g., sounding reference signal (SRS), DM-RS), uplink control information (UCI) (e.g., channel state information (CSI), hybrid automatic repeat request (HARQ), scheduling request (SR)), or power headroom report (PHR), etc. Although in Figure 9 Only transceiver 901 is shown in the figure. According to other implementation examples, UE 510 may include more than two RF transceivers.

[0123] Processor 903 controls the overall operation of UE 510. Processor 903 can be referred to as a control unit. For example, processor 903 sends and receives signals via transceiver 901. Furthermore, processor 903 records and retrieves data from memory 905. In addition, processor 903 can execute the functions of the protocol stack required by the communication specification. Although in Figure 9Only processor 903 is shown in this embodiment; however, according to other implementations, UE 510 may include two or more processors. Processor 903 is a set of instructions or code stored in memory 905. It may be instructions / code that are at least temporarily resident in processor 903 or a storage space storing instructions / code, or it may be part of the circuitry of processor 903. Furthermore, processor 903 may include various modules for performing communication. Processor 903 can control UE 510 to perform the actions of the embodiments.

[0124] Memory 905 stores data such as basic programs, application programs, and setting information for the operation of UE 510. Memory 905 may be referred to as a storage unit. Memory 905 may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Furthermore, memory 905 provides the stored data according to requests from processor 903. According to one embodiment, memory 905 may include memory for conditions, instructions, or setting values ​​associated with satellite communication transmission methods.

[0125] Figure 10 Examples of the constituent elements of a satellite (e.g., satellite 520) are shown.

[0126] Reference Figure 10 Satellite 520 may include at least one transceiver 1001, at least one processor 1003, and at least one memory 1005. Hereinafter, the constituent elements are described in the singular, but implementations of multiple constituent elements or sub-constituent elements are not excluded.

[0127] Transceiver 1001 performs functions for transmitting and receiving signals via a wireless channel. For example, transceiver 1001 performs conversion functions between baseband signals and bit streams according to the system's physical layer specifications. For instance, when transmitting data, transceiver 1001 encodes and modulates the transmitted bit stream to generate complex-valued symbols. And when receiving data, transceiver 1001 recovers the received bit stream by demodulating and decoding the baseband signal. Furthermore, transceiver 1001 uplinks the baseband signal to an RF (radiofrequency) band signal and transmits it through an antenna, and downlinks the RF band signal received through the antenna back to a baseband signal. For this purpose, transceiver 1001 may include transmit filters, receive filters, amplifiers, mixers, oscillators, digital-to-analog converters (DACs), analog-to-digital converters (ADCs), etc. Furthermore, transceiver 1001 may include multiple transmit and receive paths. Furthermore, the transceiver 1001 may include at least one antenna array composed of multiple antenna elements. From a hardware perspective, the transceiver 1001 may be composed of digital units and analog units, and the analog units may be configured into multiple sub-units depending on the operating power, operating frequency, etc. The transceiver 1001 transmits and receives signals as described above. Therefore, the transceiver 1001 may be referred to as a "transmitting unit," a "receiving unit," or a "transceiver unit."

[0128] In addition to wireless channels, transceiver 1001 may also transmit or receive signals via backhaul networks, optical communication, Ethernet, or other wired paths. For example, transceiver 1001 may support optical communication for signaling between satellite 520 and other satellites. Satellite 520 may perform optical communication with other satellites via transceiver 1001 and by using lasers. For example, it may also support wired communication between components within satellite 520. Transceiver 1001 may convert bit streams transmitted from satellite 520 to other nodes (e.g., other access nodes, other base stations, upper-level nodes, core networks, etc.) into physical signals, and convert physical signals received from other nodes into bit streams.

[0129] Transceiver 1001 can support communication between satellite 520 and UE 510. In addition to supporting communication between satellite 520 and UE 510, transceiver 1001 can also support communication between satellite 520 and terrestrial components (e.g., network entities of NTN gateway 530 and core network 550). As a non-limiting example, the circuitry within transceiver 1001 for communication with UE 510 and the circuitry for communication with the terrestrial components (e.g., network entities of NTN gateway 530 and core network 550) can be separated from each other.

[0130] Processor 1003 can control the overall operation of satellite 520. For example, processor 1003 records and reads data in memory 1005. For example, processor 1003 transmits and receives signals via transceiver 1001. Although Figure 10 A processor is shown, but embodiments of this disclosure are not limited thereto. To perform embodiments of this disclosure, satellite 520 may include at least one processor (e.g., multiple processors). Processor 1003 may be referred to as a control unit or control means. According to embodiments of this disclosure, processor 1003 may control satellite 520 to perform at least one of the actions or methods according to embodiments of this disclosure.

[0131] Memory 1005 can store basic programs, application programs, setting information, and other data used for the operation of satellite 520. Memory 1005 can store diverse data used by at least one component (e.g., transceiver 1001, processor 1003). Data may include, for example, software and input or output data related to associated instructions. Memory 1005 can be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Furthermore, memory 1005 can provide stored data upon request from processor 1003.

[0132] In embodiments of this disclosure, an apparatus is provided for providing NTN (non-terrestrial network) access to a satellite. The apparatus may include: a memory containing instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the apparatus may be configured to: transmit a message to a UE (user equipment) including information associated with a Store and Forward (S&F) mode, and perform communication with the UE based on the message. The message may contain at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of a service link between the UE and the satellite in the S&F mode; information related to the validity period of a feeder link between the satellite and an NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode.

[0133] For example, the message may include at least one of the following: information related to the paging cycle for the S&F mode; information related to the paging frame for the S&F mode; information related to the paging occasion for the S&F mode; information related to the number of paging monitoring events for the S&F mode; and information related to the paging radio network temporary identifier (P-RNTI) for the S&F mode.

[0134] For example, the message may include at least one of the following: information related to the on-duration of discontinuous reception (DRX) for the S&F mode; information related to the DRX retransmission timer for the S&F mode; information related to the DRX inactivity timer for the S&F mode; information related to the DRX cycle length for the S&F mode; information related to the DRX short-cycle timer for the S&F mode; and information indicating whether DRX is supported in the S&F mode.

[0135] For example, the message may include at least one of the following: packet data unit (PDU) session information for the S&F mode, evolved packet system (EPS) information, data radio bearer (DRB) information, identification code (ID) of the feeder link between the satellite and the NTN gateway, identification code (ID) of the satellite, cell selection parameters for the S&F mode, and information related to event triggering conditions for the S&F mode.

[0136] For example, the message may contain information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

[0137] In embodiments of this disclosure, a UE (user equipment) for performing NTN (non-terrestrial network) access is provided. The UE may include: a memory including instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the UE may be configured to: receive a message from a satellite configured to perform eNB (evolved node B) functions, including information associated with S&F (store and forward) mode, and perform communication with the satellite based on the message. The message may include at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of the service link between the UE and the satellite in the S&F mode; information related to the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode.

[0138] For example, the message may include at least one of the following: information related to the paging cycle for the S&F mode; information related to the paging frame for the S&F mode; information related to the paging occasion for the S&F mode; information related to the number of paging monitoring times for the S&F mode; and information related to the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode.

[0139] For example, the message may include at least one of the following: information related to the DRX (discontinuous reception) on-duration for the S&F mode; information related to the DRX retransmission timer for the S&F mode; information related to the DRX inactivity timer for the S&F mode; information related to the DRX cycle length for the S&F mode; information related to the DRX short-cycle timer for the S&F mode; and information indicating whether DRX is supported in the S&F mode.

[0140] For example, the message may include at least one of the following: PDU (packet data unit) session information for the S&F mode, EPS (evolved packet system) information, DRB (data radio bearer) information, the ID of the feeder link between the satellite and the NTN gateway, the ID of the satellite, cell selection parameters for the S&F mode, and information related to event triggering conditions for the S&F mode.

[0141] For example, the message may contain information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

[0142] In embodiments of this disclosure, a method is provided performed by a satellite for providing NTN (non-terrestrial network) access. The method may include: transmitting a message to a user equipment (UE) including information associated with a store-and-forward (S&F) mode; and performing communication with the UE based on the message. The message may contain at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of a service link between the UE and the satellite in the S&F mode; information related to the validity period of a feeder link between the satellite and an NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode.

[0143] For example, the message may include at least one of the following: information related to the paging cycle for the S&F mode; information related to the paging frame for the S&F mode; information related to the paging occasion for the S&F mode; information related to the number of paging monitoring times for the S&F mode; and information related to the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode.

[0144] For example, the message may include at least one of the following: information related to the DRX (discontinuous reception) on-duration for the S&F mode; information related to the DRX retransmission timer for the S&F mode; information related to the DRX inactivity timer for the S&F mode; information related to the DRX cycle length for the S&F mode; information related to the DRX short-cycle timer for the S&F mode; and information indicating whether DRX is supported in the S&F mode.

[0145] For example, the message may include at least one of the following: PDU (packet data unit) session information for the S&F mode, EPS (evolved packet system) information, DRB (data radio bearer) information, the ID of the feeder link between the satellite and the NTN gateway, the ID of the satellite, cell selection parameters for the S&F mode, and information related to event triggering conditions for the S&F mode.

[0146] For example, the message may contain information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

[0147] In embodiments of this disclosure, a method is provided performed by a UE (user equipment) for performing NTN (non-terrestrial network) access. The method may include: receiving a message from a satellite configured to perform eNB (evolved node B) functions, including information associated with a store and forward (S&F) mode; and performing communication with the satellite based on the message. The message may contain at least one of the following: information indicating that the satellite supports the S&F mode; information related to the validity period of a service link between the UE and the satellite in the S&F mode; information related to the validity period of a feeder link between the satellite and the NTN gateway in the S&F mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells supporting the S&F mode.

[0148] For example, the message may include at least one of the following: information related to the paging cycle for the S&F mode; information related to the paging frame for the S&F mode; information related to the paging occasion for the S&F mode; information related to the number of paging monitoring times for the S&F mode; and information related to the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode.

[0149] For example, the message may include at least one of the following: information related to the DRX (discontinuous reception) on-duration for the S&F mode; information related to the DRX retransmission timer for the S&F mode; information related to the DRX inactivity timer for the S&F mode; information related to the DRX cycle length for the S&F mode; information related to the DRX short-cycle timer for the S&F mode; and information indicating whether DRX is supported in the S&F mode.

[0150] For example, the message may include at least one of the following: PDU (packet data unit) session information for the S&F mode, EPS (evolved packet system) information, DRB (data radio bearer) information, the ID of the feeder link between the satellite and the NTN gateway, the ID of the satellite, cell selection parameters for the S&F mode, and information related to event triggering conditions for the S&F mode.

[0151] For example, the message may contain information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

[0152] The methods of the embodiments described in the claims or specification of this disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0153] In the case of software implementation, a computer-readable storage medium may be provided that stores one or more programs (software modules). The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs contain instructions that cause the electronic device to perform the methods of the embodiments described in the claims or specification of this disclosure.

[0154] Such programs (software modules, software) can be stored in random access memory, including non-volatile memory such as flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they can be stored in a memory consisting of some or all of these components. Furthermore, multiple components of the memory may be included.

[0155] Furthermore, the program can be stored on an attachable storage device accessible via a communication network consisting of a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. Such a storage device can be connected to the apparatus executing embodiments of this disclosure via an external port. Additionally, additional storage devices on the communication network can also be connected to the apparatus executing embodiments of this disclosure.

[0156] In the specific embodiments of this disclosure described above, the constituent elements included in this disclosure are represented in a singular or plural form depending on the specific embodiment presented. However, the singular or plural representation is chosen for ease of explanation and suitably to the presented situation, and this disclosure is not limited to a singular or plural constituent element; even constituent elements represented in a plural form may be constituted in a singular form, or even constituent elements represented in a singular form may be constituted in a plural form.

[0157] Furthermore, although specific embodiments have been described in the foregoing description of this disclosure, various modifications may be made without departing from the scope of this disclosure.

Claims

1. An apparatus for providing satellite access to non-terrestrial networks, characterized in that, include: Memory, including instructions, At least one processor, and At least one transceiver; When the instructions are executed by the at least one processor, the device is configured to: Transmit a message to the user equipment that includes information associated with the store-and-forward mode. Based on the message, communication is performed with the user equipment; The message includes at least one of the following: information indicating that the satellite supports the store-and-forward mode; information related to the validity period of the service link between the user equipment and the satellite in the store-and-forward mode; information related to the validity period of the feeder link between the satellite and the non-terrestrial network gateway in the store-and-forward mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells that support the store-and-forward mode.

2. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The message includes at least one of the following: information related to the paging cycle for the store-and-forward mode, information related to the paging frame for the store-and-forward mode, information related to the paging timing for the store-and-forward mode, information related to the number of paging monitoring times for the store-and-forward mode, and information related to the temporary identifier of the paging radio network for the store-and-forward mode.

3. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The message includes at least one of the following: information related to the discontinuous reception activation period for the store-and-forward mode; information related to the discontinuous reception retransmission timer for the store-and-forward mode; information related to the discontinuous reception inactivation timer for the store-and-forward mode; information related to the discontinuous reception period length for the store-and-forward mode; information related to the discontinuous reception short-period timer for the store-and-forward mode; and information indicating whether discontinuous reception is supported in the store-and-forward mode.

4. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The message includes at least one of the following: Packet Data Unit session information for the store-and-forward mode, evolved Packet System information, data radio bearer information, identification code of the feeder link between the satellite and the non-terrestrial network gateway, identification code of the satellite, cell selection parameters for the store-and-forward mode, and information related to event triggering conditions for the store-and-forward mode.

5. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The message contains information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

6. A user equipment for performing non-terrestrial network access, characterized in that, include: Memory, including instructions, At least one processor, and At least one transceiver; When the instruction is executed by the at least one processor, the user equipment is configured to: Receive messages from satellites configured to perform enhanced Node B functions, including information associated with store-and-forward modes. Based on the message, communication is performed with the satellite; The message includes at least one of the following: information indicating that the satellite supports the store-and-forward mode; information related to the validity period of the service link between the user equipment and the satellite in the store-and-forward mode; information related to the validity period of the feeder link between the satellite and the non-terrestrial network gateway in the store-and-forward mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells that support the store-and-forward mode.

7. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The message includes at least one of the following: information related to the paging cycle for the store-and-forward mode, information related to the paging frame for the store-and-forward mode, information related to the paging timing for the store-and-forward mode, information related to the number of paging monitoring times for the store-and-forward mode, and information related to the temporary identifier of the paging radio network for the store-and-forward mode.

8. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The message includes at least one of the following: information related to the discontinuous reception activation period for the store-and-forward mode; information related to the discontinuous reception retransmission timer for the store-and-forward mode; information related to the discontinuous reception inactivation timer for the store-and-forward mode; information related to the discontinuous reception period length for the store-and-forward mode; information related to the discontinuous reception short-period timer for the store-and-forward mode; and information indicating whether discontinuous reception is supported in the store-and-forward mode.

9. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The message includes at least one of the following: Packet Data Unit session information for the store-and-forward mode, evolved Packet System information, data radio bearer information, identification code of the feeder link between the satellite and the non-terrestrial network gateway, identification code of the satellite, cell selection parameters for the store-and-forward mode, and information related to event triggering conditions for the store-and-forward mode.

10. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The message contains information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

11. A method for providing non-terrestrial network access, performed by a satellite, characterized in that, include: The action of transmitting a message to a user equipment, including information associated with the store-and-forward mode, and Based on the message, perform communication actions with the user equipment; The message includes at least one of the following: information indicating that the satellite supports the store-and-forward mode; information related to the validity period of the service link between the user equipment and the satellite in the store-and-forward mode; information related to the validity period of the feeder link between the satellite and the non-terrestrial network gateway in the store-and-forward mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells that support the store-and-forward mode.

12. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The message includes at least one of the following: information related to the paging cycle for the store-and-forward mode, information related to the paging frame for the store-and-forward mode, information related to the paging timing for the store-and-forward mode, information related to the number of paging monitoring times for the store-and-forward mode, and information related to the temporary identifier of the paging radio network for the store-and-forward mode.

13. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The message includes at least one of the following: information related to the discontinuous reception activation period for the store-and-forward mode; information related to the discontinuous reception retransmission timer for the store-and-forward mode; information related to the discontinuous reception inactivation timer for the store-and-forward mode; information related to the discontinuous reception period length for the store-and-forward mode; information related to the discontinuous reception short-period timer for the store-and-forward mode; and information indicating whether discontinuous reception is supported in the store-and-forward mode.

14. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The message includes at least one of the following: Packet Data Unit session information for the store-and-forward mode, evolved Packet System information, data radio bearer information, identification code of the feeder link between the satellite and the non-terrestrial network gateway, identification code of the satellite, cell selection parameters for the store-and-forward mode, and information related to event triggering conditions for the store-and-forward mode.

15. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The message contains information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

16. A method for performing non-terrestrial network access, executed by a user equipment, characterized in that, include: The action of receiving messages, including information associated with store-and-forward modes, from a satellite configured to perform the functions of an enhanced Node B, and Based on the message, perform communication actions with the satellite; The message includes at least one of the following: information indicating that the satellite supports the store-and-forward mode; information related to the validity period of the service link between the user equipment and the satellite in the store-and-forward mode; information related to the validity period of the feeder link between the satellite and the non-terrestrial network gateway in the store-and-forward mode; ephemeris information of the satellite; footprint information provided by the satellite; and information related to a list of neighboring cells that support the store-and-forward mode.

17. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The message includes at least one of the following: information related to the paging cycle for the store-and-forward mode, information related to the paging frame for the store-and-forward mode, information related to the paging timing for the store-and-forward mode, information related to the number of paging monitoring times for the store-and-forward mode, and information related to the temporary identifier of the paging radio network for the store-and-forward mode.

18. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The message includes at least one of the following: information related to the discontinuous reception activation period for the store-and-forward mode; information related to the discontinuous reception retransmission timer for the store-and-forward mode; information related to the discontinuous reception inactivation timer for the store-and-forward mode; information related to the discontinuous reception period length for the store-and-forward mode; information related to the discontinuous reception short-period timer for the store-and-forward mode; and information indicating whether discontinuous reception is supported in the store-and-forward mode.

19. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The message includes at least one of the following: Packet Data Unit session information for the store-and-forward mode, evolved Packet System information, data radio bearer information, identification code of the feeder link between the satellite and the non-terrestrial network gateway, identification code of the satellite, cell selection parameters for the store-and-forward mode, and information related to event triggering conditions for the store-and-forward mode.

20. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The message contains information related to a first follower satellite that is to provide services to the first footprint of the satellite and information related to a second follower satellite that is to provide services to the second footprint of the target satellite.

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