Apparatus and method for IoT non-terrestrial networks

Abstract

We provide satellite equipment for providing NTN (non-terrestrial network) access. [Solution] In a wireless communication system, the satellite equipment transmits a message to the UE (user equipment) containing information related to the S&F (store and forward) mode, and communicates with the UE based on the message. The message includes at least one of the following: information indicating that the satellite supports the S&F mode; information regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode.

Description

【Technical Field】 【0001】 The present disclosure relates to a non-terrestrial network (NTN) that provides a wireless communication service generally via a satellite located in the Earth's orbit or an aerial vehicle flying at a high altitude rather than a terrestrial base station. More specifically, it relates to an apparatus and method for an IoT (Internet of Everything) NTN (non-terrestrial network). 【Background Art】 【0002】 A non-terrestrial network (NTN) has been introduced to supplement a terrestrial network that provides a wireless communication system. The non-terrestrial network can provide communication services even in areas where it is difficult to construct a terrestrial network or in disaster situations. Furthermore, due to the recent reduction in satellite launch costs, it has become possible to provide an efficient access network environment. 【Summary of the Invention】 【Means for Solving the Problems】 【0003】 Embodiments of this disclosure provide a satellite device for providing NTN (non-terrestrial network) access. The device 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 device may cause a message to be sent to a user equipment (UE) containing information related to store and forward (S&F) mode, and to communicate with the UE 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 regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. 【0004】 Embodiments of this disclosure provide user equipment (UE) for performing NTN (non-terrestrial network) access. The UE may include memory containing instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the UE may receive a message from a satellite configured to perform evolved node B (eNB) functions, containing information related to store and forward (S&F) mode, and based on the message, initiate communication with the satellite. The message may include at least one of the following: information indicating that the satellite supports the S&F mode; information regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. 【0005】 Embodiments of this disclosure provide a method performed by a satellite for providing NTN (non-terrestrial network) access. This method may include sending a message to a user equipment (UE) containing information related to store and forward (S&F) mode, and communicating with the UE 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 regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. 【0006】 Embodiments of this disclosure provide a method performed by user equipment (UE) for performing NTN (non-terrestrial network) access. This method may include receiving a message from a satellite configured to perform evolved node B (eNB) functions, the message containing information related to store and forward (S&F) mode, and communicating 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 regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. [Brief explanation of the drawing] 【0007】 [Figure 1] This shows a wireless communication system. [Figure 2a] An example of a non-terrestrial network (NTN) is shown. [Figure 2b] An example of a non-terrestrial network (NTN) is shown. [Figure 3a] An example of a control plane (C-plane) is shown. [Figure 3b] An example of a user plane (U-plane) is shown. [Figure 4] This shows an example of a resource structure in the time-frequency domain in a wireless communication system. [Figure 5] This example shows the S&F (store and forward) mode in IoT (Internet of Everything) NTN (non-terrestrial network). [Figure 6] This shows the satellite connection status and UE (user equipment) connection status in S&F mode. [Figure 7] This shows the signaling for UE pre-action in S&F mode. [Figure 8a] This shows an example of the paging procedure in S&F mode. [Figure 8b] This shows an example of DRX (discontinuous reception) operation in S&F mode. [Figure 9] Here are some examples of UE components. [Figure 10] Examples of satellite components are shown. [Modes for carrying out the invention] 【0008】 The terms used in this disclosure are used solely to describe specific embodiments and are not intended to limit the scope of other embodiments. Singular expressions can, in context, include plural expressions unless otherwise specified. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by a person of ordinary skill in the art described herein. Terms used herein that are defined in a general dictionary may be interpreted as having the same or similar meaning as in the context of the relevant art, and not as ideally or excessively formal unless expressly defined herein. In some cases, terms defined herein may not be interpreted in a way that excludes embodiments of this disclosure. 【0009】 The various embodiments of the Disclosure described below illustrate hardware-based approaches as examples. However, since the various embodiments of the Disclosure include techniques that use both hardware and software, the various embodiments of the Disclosure do not exclude software-based approaches. 【0010】 The terms used in the following description, such as those referring to signals (e.g., signal, information, message, signaling), resources (e.g., symbol, slot, subframe, radio frame, subcarrier, RE (resource element), RB (resource block), BWP (bandwidth part), occasion), operational states (e.g., step, operation, procedure), data (e.g., packet, user stream, information, bit, symbol, codeword), channels, network entities, and device components, are provided as examples for illustrative purposes only. Therefore, this disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used. 【0011】 In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, PDSCH (physical downlink shared channel) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. In other words, in this disclosure, the expression "transmit a physical channel" may be interpreted as equivalent to the expression "transmit data or a signal over a physical channel." 【0012】 Hereinafter, in this disclosure, "upper signaling" means a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel. Upper signaling may be understood as RRC (radio resource control) signaling or MAC control element (hereinafter referred to as "CE"). 【0013】 Furthermore, this disclosure may use expressions greater than or less than to determine whether a particular condition is satisfied or fulfilled, but this is merely an illustrative example and does not preclude the use of greater than or less than expressions. Conditions described as "greater than or equal to" may be replaced with "greater than or equal to," conditions described as "less than or equal to" may be replaced with "less than or equal to," and conditions described as "greater than or equal to and less than" may be replaced with "greater than and less than or equal to." Also, hereafter, "A" to "B" means at least one of the elements from A to B (including A). Hereinafter, "C" and / or "D" means including at least one of "C" or "D," i.e., {"C", "D", "C", and "D"}. 【0014】 In this disclosure, signal quality may be at least one of the following: RSRP (reference signal received power), BRSRP (beam reference signal received power), RSRQ (reference signal received quality), RSSI (received signal strength indicator), SINR (signal to interference and noise ratio), CINR (carrier to interference and noise ratio), SNR (signal to noise ratio), EVM (error vector magnitude), BER (bit error rate), or BLER (block error rate). Needless to say, in addition to the examples above, other terms or metrics representing channel quality with equivalent technical meaning may be used. Hereinafter in this disclosure, high signal quality means that the signal quality value related to signal size is large or the signal quality value related to error rate is small. Higher signal quality may mean that a smoother wireless communication environment is guaranteed. The optimal beam may mean the beam with the highest signal quality within the beam. 【0015】 The present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project), ETSI (European Telecommunications Standards Institute)), but this is merely for illustrative purposes. Various embodiments of the present disclosure can be easily modified and applied in other communication systems. 【0016】 FIG. 1 shows a wireless communication system. 【0017】 Referring to FIG. 1, FIG. 1 shows a radio interface of a radio access technology (RAT), and shows a terminal 110 and a base station 120 as part of a node that utilizes a radio channel in a wireless communication system using EUTRAN (evolved UMTS (Universal Mobile Telecommunications System) radio access network) or NR (New Radio). Although FIG. 1 shows only one base station, the wireless communication system may further include other base stations identical or similar to the base station (e.g., LTE eNB or NR gNB) 120. 【0018】 The terminal 110 is a device used by a user and communicates with the base station 120 via a wireless channel. The link from the base station 120 to the terminal 110 is called the downlink (DL), and the link from the terminal 110 to the base station 120 is called the uplink (UL). Although not shown in FIG. 1, the terminal 110 and other terminals can communicate with each other via a wireless channel. In this case, the link between the terminal 110 and other terminals (device-to-device link, D2D) is called a sidelink, and this sidelink can be used interchangeably with the PC5 interface. In some other embodiments, the terminal 110 can be operated without user involvement. According to one embodiment, the terminal 110 is a device that executes machine type communication (MTC) and may not be carried by a user. Further, according to one embodiment, the terminal 110 can be a NB (Narrowband)-IoT (Internet of thing) device. 【0019】 In describing the systems and methods herein, the terminal 110 can be an electronic device used to communicate voice and / or data to the base station 120, and the base station 120 can in turn communicate with a network of devices (e.g., a public switched telephone network (PSTN), the Internet, etc.). 【0020】 Furthermore, terminal 110 may be referred to as "user equipment (UE)", "vehicle", "customer premises equipment (CPE)", "mobile station", "subscriber station", "remote terminal", "wireless terminal", "electronic device", or "user device", "access terminal", "mobile terminal", "remote station", "user terminal", "subscriber unit", "mobile device", or other terms with equivalent technical meaning. 【0021】 Examples of terminal 110 include mobile phones, smartphones, personal digital assistants (PDAs), laptop computers, netbooks, e-readers, and wireless modems. In the 3GPP standard, terminal 110 is typically referred to as a UE. However, since the scope disclosed herein should not be limited to the 3GPP standard, the terms “UE” and “terminal” may be used interchangeably herein to mean the more general term “wireless communication device.” A UE may more generally be referred to as a terminal equipment device. 【0022】 A base station 120 is network infrastructure that provides wireless connectivity to terminals 110. Terminals 110 have coverage defined based on the distance over which they can transmit signals. In 3GPP standards, base stations 120 may be referred to as "Node B," "Evolved Node B (eNodeB, eNB)," "5G node (5th generation node)," "Next generation node B (gNB)," "Home Enhanced or Evolved Node B (HeNB)," as well as "Access point (AP)," "Wireless point," "Transmission / reception point (TRP)," or other terms with equivalent technical meaning. 【0023】 Since the scope of what is disclosed herein should not be limited to 3GPP standards, the terms “base station,” “node B,” “eNB,” and “HeNB” may be used interchangeably herein to mean the more general term “base station.” Furthermore, the term “base station” may be used to represent an access point. An access point may be an electronic device that provides access to a network for wireless communication devices (e.g., a local area network (LAN), the Internet, etc.). The term “communication device” may be used to represent both a wireless communication device and / or a base station. An eNB or gNB may be more generally referred to as a base station device. 【0024】 The base station 120 can communicate with the core network entity 130. For example, the core network entity 130 may include a mobility management entity (MME) responsible for the control plane, such as terminal 110 connectivity and mobility control functions, and a serving gateway (S-GW) responsible for control functions over user data. 【0025】 Terminal 110 can perform beamforming with base station 120. Terminal 110 and base station 120 can transmit and receive radio signals in relatively low frequency bands (e.g., NR FR1 (frequency range 1)). Terminal 110 and base station 120 can also transmit and receive radio signals in relatively high frequency bands (e.g., NR FR2 (or FR2-1, FR2-2, FR2-3), FR3) and millimeter wave (mmWave) bands (e.g., 28GHz, 30GHz, 38GHz, 60GHz). To improve channel gain, terminal 110 and base station 120 can perform beamforming. Here, beamforming may include transmit beamforming and / or receive beamforming. Terminal 110 and base station 120 can impart directionality to the transmitted or received signal. For this purpose, terminal 110 and base station 120 can select a serving beam through a beam search or beam management procedure. After the serving beam is selected, communication may be carried out through a resource that has a Quasi Co-Location (QCL) relationship with the resource that transmitted the serving beam. 【0026】 If the large-scale characteristics of the channel that transmitted the symbol on the first antenna port can be inferred from the channel that transmitted the symbol on the second antenna port, then the first and second antenna ports can be evaluated as being in a QCL relationship. For example, the large-scale characteristics may include at least one of the following: delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameter. 【0027】 Both terminal 110 and base station 120 can perform beamforming, but the embodiments of this disclosure are not necessarily limited thereto. In some embodiments, terminal 110 may or may not perform beamforming. Similarly, base station 120 may or may not perform beamforming. That is, either terminal 110 or base station 120 may perform beamforming alone, or neither terminal 110 nor base station 120 may perform beamforming. 【0028】 In this disclosure, "beam" means the spatial flow of a signal in a radio channel, which is formed by one or more antennas (or antenna elements), and such a formation process may be referred to as beamforming. Beamforming may include at least one of analog beamforming or digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming may include, for example, DM-RS (demodulation-reference signal), CSI-RS (channel state information-reference signal), SS / PBCH (synchronization signal / physical broadcast channel), and SRS (sounding reference signal). Furthermore, an information element (IE), such as a CSI-RS resource or an SRS resource, may be used as the configuration of each reference signal, and such a configuration may include information associated with the beam. Beam-related information can mean whether the configuration (e.g., a CSI-RS resource) uses the same spatial domain filter as other configurations (e.g., other CSI-RS resources within the same CSI-RS resource set), or uses a different spatial domain filter, or which reference signal it is quasi-co-located with, and if so, what type of quasi-co-located 【0029】 In the following description of the embodiments, the terminal may be referred to as UE110, and the base station may be referred to as eNB120 or gNB120. In this disclosure, eNB120 is described as an example of a node providing an access network in order to describe IoT NTN for IoT UE, but it goes without saying that the same or similar methods can be applied to gNB120. 【0030】 Figures 2a and 2b illustrate examples of non-terrestrial networks (NTNs). Figure 2a shows an example of a non-terrestrial network (NTN) utilizing transparent satellites. Figure 2b shows an example of a non-terrestrial network (NTN) utilizing regenerative satellites. NTN refers to an access network that provides non-terrestrial access to UEs (such as UE110) via NTN payloads and NTN gateways mounted on airborne or space-borne NTN vehicles. The access network may be provided via one or more eNBs (e.g., eNB120). 【0031】 Referring to Figure 2a, NTN200 represents the network environment provided by the transparent satellite. NTN200 can include NTN payload 221 and NTN gateway 223 as eNB120. NTN payload 221 is a network node mounted on a satellite or HAPS (high altitude platform station) that provides connectivity between a service link (described later) and a feeder link (described later). NTN gateway 223 is an earth station located on the Earth's surface that provides connectivity to NTN payload 221 using the feeder link. NTN gateway 223 is a TNL (transport network layer) node. NTN200 can provide non-terrestrial access to UE110. NTN200 can provide non-terrestrial access to UE110 via NTN payload 221 and NTN gateway 223. The link between NTN payload 221 and UE110 may be referred to as a service link. The link between the NTN gateway 223 and the NTN payload 221 may be referred to as a feeder link. A feeder link may correspond to a wireless link. 【0032】 The NTN payload 221 can receive radio protocol data from the UE 110 via the service link. The NTN payload 221 can transparently transmit the radio protocol data to the NTN gateway 223 via the feeder link. Therefore, from the perspective of the UE 110, the NTN payload 221 and the NTN gateway 223 can appear as a single eNB 120. The NTN payload 221 and the NTN gateway 223 can communicate with the UE 110 via the Uu interface, which is a common radio protocol. That is, the NTN payload 221 and the NTN gateway 223 can communicate with the UE 110 via radio protocol, just like a single eNB 120. The NTN gateway 223 can communicate with the core network entity 235 (MME (mobility management entity) or S-GW (serving gateway)) via the S1 interface. 【0033】 According to one embodiment, the NTN payload 221 and NTN gateway 223 can use the wireless protocol stack in the control plane shown in Figure 3a, which will be described later. Furthermore, according to one embodiment, the NTN payload 221 and NTN gateway 223 can use the wireless protocol stack in the user plane shown in Figure 3b. 【0034】 Figure 2a illustrates one NTN payload 221 and one NTN gateway 223 included in the eNB 120, but embodiments of the present disclosure are not limited thereto. For example, an eNB may include multiple NTN payloads. Furthermore, for example, an NTN payload may be provided by multiple eNBs. In other words, the implementation scenario shown in Figure 2a is an example and does not limit embodiments of the present disclosure. 【0035】 Referring to Figure 2b, NTN250 represents the network environment provided by the regenerative satellite. NTN250 may include satellite 260 operating as eNB120. Satellite 260 represents a space-borne vehicle carrying a regenerative payload communications transmitter located in low-earth orbit (LEO), medium-earth orbit (MEO), or geostationary earth orbit (GEO). Satellite 260 may be referred to as a regenerative payload or regenerative satellite. Satellite 260 represents a payload configured to convert and amplify uplink RF signals before transmitting them downlink, and the conversion of such signals may mean digital processing that includes demodulation, decoding, recoding, remodulation, and / or filtering. NTN250 may include NTN Gateway 265, which is a ground-based entity connected to satellite 260. NTN Gateway 265 is an earth station located on the Earth's surface that provides connectivity to satellite 260 using the feeder link. NTN250 can provide non-terrestrial access to UE110. NTN250 can provide non-terrestrial access to UE110 via satellite 260 and NTN Gateway 265. 【0036】 Satellite 260 may be configured to regenerate signals received from terminal 110 or an earth station (e.g., NTN gateway 265). A Uu interface may be defined between satellite 260 and terminal 110. A satellite radio interface (SRI) on the feeder link may be defined between satellite 260 and NTN gateway 265. Although not shown in Figure 2b, satellite 260 can provide inter-satellite links (ISL). The ISL is an inter-satellite transmission link and may be a 3GPP or non-3GPP defined radio interface (e.g., X2 interface or XN interface) or an optical interface. Satellite 260 can communicate with core network entity 235 (e.g., MME or S-GW) via the S1 interface based on NTN gateway 265. According to one embodiment, satellite 260 can utilize the radio protocol stack in the control plane of Figure 3a, described later. Furthermore, according to one embodiment, satellite 260 can utilize the radio protocol stack in the user plane shown in Figure 3b. 【0037】 Figure 2b illustrates satellite 260 operating as eNB120, but embodiments of the present disclosure are not limited thereto. An eNB120 according to embodiments of the present disclosure can be implemented in a distributed deployment utilizing a centralized unit (CU) configured to perform upper layer functions of the access network (e.g., PDCP (packet data convergence protocol), RRC (radio resource control)) and distributed units (DUs) configured to perform lower layer functions. The interface between the CU and the distributed unit may be referred to as an F1 interface. The centralized unit (CU) is connected to one or more DUs and can perform functions higher than those of the DUs. For example, the CU may be responsible for the RRC (radio resource control) and PDCP (packet data convergence protocol) layers, while the DU and RU (radio unit) are responsible for lower layer functions. The DU may be responsible for the RLC (radio link control), MAC (media access control), and PHY (physical) layer functions. In this distributed configuration, satellite 260 can be used as a CU or DU constituting eNB120. 【0038】 Figure 3a shows an example of a control plane (C-plane). At least some of the following description of eNB120 may be understood to apply to satellite 260. 【0039】 Referring to Figure 3a, in the C plane, the UE110 and AMF235 can perform NAS (non-access stratum) signaling. In the C plane, the UE110 and eNB120 can communicate according to the protocols specified in the RRC layer, PDCP layer, RLC layer, MAC layer, and PHY layer, respectively. 【0040】 In NTN Access, the main functions of the RRC layer include at least some of the following: - AS (Access Stratum) and NAS-related system information broadcasting - Paging - Setting up, maintaining, and disconnecting RRC connections between the UE and the access network, including, more specifically, control over RLC, MAC, and PHY: - Adding, modifying, and removing Carrier Aggregations - Adding, modifying, and removing dual connectivity between NR or E-UTRA and NR. - Security features including key management - Setting up, configuring, maintaining, and deactivating SRB (Signaling Radio Bearer) and DRB (Data Radio Bearer) - Includes the following mobility features: - Handover and context transmission - Selection and re-selection of UE cells, and control of cell selection and re-selection. - Mobility between RATs - QoS (Quality of Service) management function - UE measurement reporting and reporting control - Detection and recovery of radio link failures. - Send messages from / to the UE, to / from the NAS, and to the NAS. 【0041】 In NTN Access, the main functions of the PDCP layer include at least some of the following functions: - Header compression and decompression function (ROHC only) - User data transmission function - Sequential delivery of upper layer PDUs - Out-of-sequence delivery of upper layer PDUs - Duplicate detection function (Duplicate detection of lower layer SDUs) - Retransmission function (Retransmission of PDCP SDUs) - Encryption and deciphering functions - Timer-based SDU discard function (SDU discard in uplink). 【0042】 In NTN Access, the main functions of the RLC layer include at least some of the following: - Data transmission function (Transfer of upper layer PDUs) - Sequential 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 function (RLC data PDUs) - Reordering function for RLC data PDUs - Duplicate detection function - Error detection function (Protocol error detection) - RLC SDU deletion function (RLC SDU discard) - RLC re-establishment function. 【0043】 In NTN access, the MAC layer may be connected to several RLC layer devices configured in a single terminal, and the main functions of the MAC may include at least some of the following: - Mapping function between logical channels and transport channels - MAC SDU multiplexing and demultiplexing functionality - Scheduling information reporting function - Error correction through HARQ functionality - Priority handling between logical channels of one UE (Unified Element) - Priority handling between UEs by means of dynamic scheduling - MBMS service identification function - Transport format selection function - Padding function. 【0044】 In NTN Access, each entity in the physical layer (e.g., terminal 110, eNB120) can perform operations such as channel coding and modulation of higher-layer data, generating OFDM symbols and transmitting them to the radio channel, or demodulating OFDM symbols received via the radio channel, channel decoding them, and transmitting them to the higher layer. 【0045】 Figure 3b shows an example of a user plane (U-plane). At least some of the following explanation of eNB120 can be understood as relating to satellite 260. 【0046】 Referring to Figure 3b, in the U-plane, UE110 and eNB120 can communicate according to the protocols specified in 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 explanation in Figure 3a. 【0047】 Figure 4 shows an example of a time-frequency domain resource structure supported by a wireless communication system to which embodiments proposed herein may be applied. While Figure 4 illustrates an example resource structure for an LTE network for IoT NTN, embodiments of this disclosure are not limited thereto. It goes without saying that signaling and related operations according to embodiments of this disclosure may also be applied to NR systems. 【0048】 Referring to Figure 4, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest transmission unit in the time domain is the OFDM symbol, N symbA collection of OFDM symbols 402 constitutes one slot 406 (for example, seven in an LTE system). Referring to Figure 4, in a wireless communication system to which the present invention is applied, one radio frame 414 may be defined as having a length of 10 ms, consisting of 10 subframes, each having the same length of 1 ms. A radio frame 414 may be divided into 5 ms half-frames, each half-frame containing 5 subframes. In Figure 4, slot 406 consists of 7 OFDM symbols, although the length of the slot may vary depending on the subcarrier spacing. The radio resources supported in a wireless communication system to which the invention proposed herein may be applied consist of multiple time resources, which are symbols, and multiple frequency resources, which are subcarriers, and each time resource and frequency resource may be represented as a two-dimensional resource grid. In Figure 4, one of the smallest physical resources, a rectangle consisting of one subcarrier and one symbol within the resource grid, is referred to as Resource Element (RE) 412. 【0049】 In a wireless communication system to which the invention proposed herein may be applied, the smallest transmission unit in the frequency domain is a subcarrier, and the carrier bandwidth constituting the resource grid is N BWIt may consist of multiple subcarriers 404. The basic unit of resource in the time-frequency domain is a resource element (RE) 412, which can be represented as an OFDM symbol index and a subcarrier index. A resource block 408 can contain multiple resource elements 412. In a wireless communication system to which the invention proposed herein may be applied, a resource block 408 (or physical resource block (PRB)) is N in the time domain. symb A sequence of OFDM symbols (for example, 7 symbols), and N in the frequency domain. SC RB It can be defined as 12 consecutive subcarriers. The data rate may increase in proportion to the number of RBs scheduled to the terminal. In a frequency division duplex (FDD) system where downlink and uplink are operated on separate frequencies, the downlink transmit bandwidth and the uplink transmit bandwidth may be different from each other. The channel bandwidth represents the RF (radio frequency) bandwidth corresponding to the system transmit bandwidth. For example, the channel bandwidth may be one of the following: 1.4 MHz (e.g., 6 PRB), 3 MHz (e.g., 15 PRB), 5 MHz (e.g., 25 PRB), 10 MHz (e.g., 50 PRB), 15 MHz (e.g., 75 PRB), or 20 MHz (e.g., 100 PRB). 【0050】 E-UTRAN can support wireless access via a non-terrestrial network (NTN) not only for general UEs but also for BL (Bandwidth-Limited) UEs, CE (Coverage Enhancement) UEs, and NB-IoT UEs. Support for non-terrestrial networks may include platforms that provide wireless 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). 【0051】 In the transparent payload system, the NTN gateway and the NTN payload (i.e., the satellite) work together to perform the role of the eNB, while in the regenerative payload system, the NTN payload (i.e., the satellite) can perform the role of the eNB. 【0052】 A transparent NTN payload transparently forwards the radio protocol received from the UE (over the service link) to the NTN gateway (over the feeder link), and vice versa. A regenerative payload can be terminated with the Uu interface (over the service link), S1, and X2 interfaces. An NTN gateway can support multiple transparent or regenerative NTN payloads. A transparent or regenerative NTN payload can be serviced by multiple eNBs. A regenerative NTN payload can be terminated with one or more intersatellite links leading to other regenerative payloads. As an example, a transparent NTN payload may change its carrier frequency before retransmitting over the service link, and vice versa (over the feeder links, respectively). In a non-terrestrial network, a tracking area may correspond to a fixed geographical area. In a non-terrestrial network, the same value may be used when the satellite ID refers to the same satellite in both the AS and the NAS. 【0053】 In non-terrestrial networks, three types of service links may be supported. 【0054】 • Earth-fixed: Provisioned with a beam that continuously covers the same geographical area at all times (e.g., GSO satellites). 【0055】 • Quasi-Earth-fixed: Provisioned with a beam that covers one geographical region for a limited period and another geographical region for other periods (e.g., when the NGSO satellite generates a steerable beam). 【0056】 • Earth-moving: The coverage area is provisioned with a beam that moves as if gliding across the Earth's surface (e.g., when NGSO satellites generate fixed or uncontrollable beams). 【0057】 eNBs using NGSO satellites may provide quasi-Earth-fixed cell coverage or Earth-moving cell coverage, while eNBs using GSO satellites may provide Earth-fixed cell coverage or quasi-Earth-fixed cell coverage. 【0058】 The store-and-forward (S&F) mode may be used to provide communication services to a UE when the serving satellite has a discontinuous connection to a ground network and that connection is unavailable when the satellite interacts with the UE. The eNB can indicate whether the cell is operating in store-and-forward mode. The store-and-forward mode means an operating mode in which the service satellite has a discontinuous connection to an NTN gateway and provides communication services to the UE when the connection to the NTN gateway is unavailable when the satellite interacts with the UE. 【0059】 Figure 5 shows an example of the S&F (store and forward) mode in IoT (Internet of Everything) NTN (non-terrestrial network). 【0060】 Referring to Figure 5, UE510 can communicate with satellite 520. UE510 may be referred to as terminal 110 in Figure 1. Satellite 520 may be referred to as base station 120 or a network entity performing at least some of the functions of base station 120. According to one embodiment, satellite 520 may be an eNB providing IoT NTN. Satellite 520 can provide E-UTRAN for IoT devices (e.g., UE510). UE510 can connect to satellite 520 via E-UTRAN. The connection between satellite 520 and UE510 may be referred to as a service link. Satellite 520 can move along a designated orbit. Depending on the movement of satellite 520, satellite 520 may connect to a ground-based network entity (hereinafter referred to as a ground segment) (e.g., NTN gateway 530). The connection between satellite 520 and NTN gateway 530 may be referred to as a feeder link. The NTN gateway 530 may be connected to the core network 550 via the transmission network 540. As the satellite 520 repeatedly moves along the designated orbit, the service link may be available or unavailable. As the satellite 520 repeatedly moves along the designated orbit, the feeder link may be available or unavailable. 【0061】 Satellite 520 can support S&F (store and forward) mode. S&F mode can represent an operating mode of a system that is satellite-accessible. Delay-tolerant communication services can be provided via S&F mode. When satellite access is intermittently or temporarily unavailable (for example, when serving a UE510 located in a coverage area where the feeder link to the ground segment (e.g., NTN Gateway 530) is not simultaneously activated), a level of service that stores and forwards data 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 a UE510 that does not have a GNSS (global navigation satellite system) receiver or has difficulty connecting to GNSS services. As a non-restrictive example, satellite 520 can perform UE-satellite-UE communication with UE510. For example, UE510 can communicate with satellite 520 without communicating with the ground segment (e.g., NTN gateway 530) to avoid long latency and limited data rates and reduce resource consumption. S&F mode can be used for latency-tolerant and / or interruption-tolerant services. For example, in a 3GPP context, SMS (short message service) may be used for S&F mode, and end-to-end connectivity between endpoints (e.g., UE510 and application server) may not be required. Only connectivity between the endpoint (e.g., UE510) and an intermediate node (e.g., SMSC (short message service center)) may be required. 【0062】 In S&F mode, the service link between UE510 and satellite 520 can alternate between available and unavailable states. When the service link between UE510 and satellite 520 is available, it indicates that the satellite 520 is located within the range where it can provide service to the area (e.g., footprint) where UE510 is located on satellite 520's orbit (hereinafter referred to as the "service-available orbit segment"). When the service link between UE510 and satellite 520 is unavailable, it indicates that the satellite 520 is located within the range where it is difficult to provide service to the area (e.g., footprint) where UE510 is located on satellite 520's orbit (hereinafter referred to as the "service-unavailable orbit segment"). In S&F mode, the feeder link between satellite 520 and the ground segment (e.g., NTN Gateway 530) can alternate between available and unavailable states. The availability of the feeder link between satellite 520 and the ground segment (e.g., NTN Gateway 530) indicates that the satellite 520 is located within the range (e.g., footprint) of the area where the ground segment (e.g., NTN Gateway 530) is located on satellite 520's orbit, where service can be provided (hereinafter referred to as the "feeder-available orbit segment"). The unavailability of the service link between satellite 520 and the ground segment (e.g., NTN Gateway 530) indicates that the satellite 520 is located within the range (e.g., footprint) of the area where the ground segment (e.g., NTN Gateway 530) is located on satellite 520's orbit, where service is difficult to provide (hereinafter referred to as the "feeder-unavailable orbit segment"). With respect to UE510, the availability of the service link and the availability of the feeder link do not necessarily occur simultaneously. For example, even if the status of the service link changes from available to unavailable, the status of the feeder link does not change. For example, even if the status of the feeder link changes from available to unavailable, the status of the service link does not change. 【0063】 According to one embodiment, UE510 can transmit a signal. The signal may be MO (mobile originated) data. For example, in operation 591, UE510 can transmit uplink data (e.g., PUSCH) to satellite 520 when the service link is available. Satellite 520 can receive the uplink data from UE510. Since the feeder link is not available, satellite 520 can store the uplink data. Satellite 520 can then move. In response to the move, the state of the feeder link may change from available to unavailable. In operation 592, satellite 520 can transmit the uplink data via a network entity located on the ground (e.g., NTN gateway 530). The uplink data can be transmitted to the data network via the core network 550. Hereinafter, in S&F mode, the service to which a message originating from UE510 via satellite 520 is transmitted may be referred to as an MO service. 【0064】 According to one embodiment, satellite 520 can transmit a signal to UE 510. The signal may be MT (mobile terminated) data. For example, in operation 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. Depending on the movement of satellite 520, the state of the feeder link may be changed from available to unavailable. Depending on the movement of satellite 520, the state of the service link between satellite 520 and UE 510 may be changed from unavailable to available. In operation 594, when the service link is available, satellite 520 can transmit downlink data (e.g., PDSCH) to UE 510. Hereinafter, in S&F mode, the service of messages transmitted from UE 510 via satellite 520 may be referred to as MT service. 【0065】 According to embodiments of the present disclosure, a network (e.g., eNB) can instruct a terminal (e.g., UE) to enter store-and-forward mode via an SIB1 message. For example, an SIB1 message may contain an 'sf-OperationMode' IE (information element). The IE may indicate that a cell is operating in store-and-forward mode. If the field is present, a UE supporting store-and-forward operation may ignore cellBarred-NTN and cellBarred. The IE may have a value of 'barred' or 'notBarred'. The value 'barred' means that the cell is barred from NTN connections via store-and-forward operation, as defined in TS 36.304. The value 'notBarred' means that the cell allows access from a UE supporting store-and-forward operation. If this field is not present, the SIB1 message may indicate that an NTN cell is operating in normal mode, i.e., in a mode other than store-and-forward mode. 【0066】 According to embodiments of the present disclosure, a network (e.g., eNB) can instruct a terminal (e.g., UE) via SIB31 time information related to store-and-forward mode. SIB31 may include satellite assistance information relating to the serving cell. The satellite assistance information may include ephemeris information, satellite ID, and reference position information in SIB31. According to one embodiment, the SIB31 message may include switching time information (e.g., t-ModeSwitching) IE. If sf-OperationMode is present in SIB1, this field indicates the time information for when the NTN cell switches from store-and-forward operating mode to normal mode. Otherwise, this field indicates the time information for when the NTN cell switches from normal mode to store-and-forward mode. 【0067】 Figure 6 shows the connection status of the satellite (e.g., satellite 520) and the UE (user equipment) in S&F mode. In Figure 6, the first UE 511, the second UE 512, and the third UE 513 are described as examples to illustrate various cases depending on the area in which the UE is located, and for each UE, the description of UE 510 in Figure 5 may be referred to. 【0068】 Referring to Figure 6, satellite 520 can move. As satellite 520 moves, the state of the feeder link between satellite 520 and the ground segment (e.g., NTN Gateway 530) can alternate between available and unavailable states. For example, in the first time interval 621, the feeder link of satellite 520 may be unavailable. Satellite 520 can operate without the feeder link. For example, in the second time interval 622, the feeder link of satellite 520 may be available. Satellite 520 can operate with the feeder link. For example, in the third time interval 623, the feeder link of satellite 520 may be unavailable. Satellite 520 can operate without the feeder link. Depending on whether the feeder link state of satellite 520 is available or unavailable, the operation of UEs in the RRC idle state (e.g., the first UE 511, the second UE 512, the third UE 513) may differ. For example, satellite 520 may not have the opportunity to connect to a ground segment (e.g., NTN Gateway 530) before the first UE 511 enters in-coverage state 631. In such a case, the first UE 511 does not need to perform paging monitoring. The first UE 511 can skip monitoring paging messages from satellite 520. For example, satellite 520 may connect to a ground segment (e.g., NTN Gateway 530) before the second UE 512 enters in-coverage state 632. In this case, even if satellite 520 is in S&F mode, the second UE 512 can perform monitoring 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 can perform normal operation (e.g., paging monitoring with or without satellite connection). 【0069】 The operation of the UEs (e.g., the first UE511, the second UE512, and the third UE513) in the RRC idle state may be determined according to the current feeder link state and the past feeder link state while the UEs were out of coverage. For example, if satellite 520 temporarily restores the feeder link, the UEs (e.g., the first UE511, the second UE512, and the third UE513) can monitor paging messages and perform data reception. If satellite 520 does not have an opportunity to restore the feeder link, the UEs can skip paging message monitoring. The operation of the UEs in the RRC idle state, depending on the current and past feeder link states, will be described in detail below with reference to Figures 7, 8a, and 8b. When satellite 520 is in S&F mode, MO data transmission may be possible to RRC idle UEs (e.g., the first UE511, the second UE512, and the third UE513). RRC idle UEs (e.g., the first UE511, the second UE512, and the third UE513) can perform initial network access and data transmission (e.g., consisting of control plane EDT (early data transmission) / CIoT (cellular IoT) tasks) when satellite 520 is in S&F mode. 【0070】 Figure 7 shows the signaling for the pre-operation of a UE (e.g., UE510) in S&F mode. Satellite 520 may be configured to perform the functions of an eNB. In one example, the eNB may be located on the board of satellite 520, and entities of the core network (e.g., core network 550) may be located on the ground. In one example, the eNB and some of the entities of the core network (or some of a specific entity (e.g., MME (mobile management entity))) may be located on the board of satellite 520, and other entities of the entities of the core network may be located on the ground. 【0071】 Referring to Figure 7, in operation 701, satellite 520 can transmit information related to feeder link recovery to UE 510. For example, assuming the second UE 512 in Figure 6, the service link between the second UE 512 and satellite 520 is active even if the feeder link of satellite 520 is unavailable. Because the service link is active, the second UE 512 can perform the operations required in the RRC idle state. The second UE 512 can perform the operations required in the RRC idle state (e.g., paging monitoring, DRX) because it has an expectation of feeder link recovery. In the RRC idle state, for the operations of the second UE 512, satellite 520 can provide the second UE 512 with information related to feeder link recovery. 【0072】 1. Signaling Information related to feeder link recovery can be provided by various signaling methods. According to one embodiment, the information related to feeder link recovery can be provided via a system information block (SIB). For example, the information related to feeder link recovery can be provided via SIB31 or SIB32. Hereinafter, SIB32 is described as an example, but this does not preclude the fact that the information described later may be transmitted by SIB31 or other SIBs. SIB32 may include satellite-aided information for predicting discontinuous coverage. SIB32 may be signaled on an NTN cell provided by satellite 520. The information related to feeder link recovery may be cell-specific. 【0073】 For example, SIB32 can be found in the table below. 【0074】 [Table 1-1] 【0075】 [Table 1-2] 【0076】 [Table 1-3] 【0077】 "carrierFreqList" represents a list of E-UTRA frequencies. "elevationAngleLeft" and "elevationAngleRight" represent the elevation angles to the left and right (referencing the satellite direction), respectively, in degrees. The actual value may be the field value multiplied by 5. "footprintInfo" represents the satellite footprint. Satellite 520 (e.g., E-UTRAN) can configure elevationAngles and / or radii for earth moving cells. Satellite 520 (e.g., E-UTRAN) can configure referencePoint and radii for quasi-earth fixed cells. "latitude" indicates the latitude (in degrees) of the reference point. "longitude" indicates the longitude (in degrees) of the reference point. "satelliteInfoList" represents a list of satellite information. "serviceInfo" represents the coverage information provided by the satellite. "tle-EphemerisParameters" represents the average values ​​of satellite orbit parameters based on a TLE set format for estimating the in-coverage and out-of-coverage periods of a satellite (e.g., satellite 520) that includes an Earth-moving cell. "t-ServiceStart" indicates time information regarding the point in time when a receiving satellite commences service to a quasi-earth fixed cell in that area. "feederlinkinfo" represents information related to feeder link recovery according to embodiments of this disclosure. In addition to the foregoing, each IE can be referenced to the TS36.331v18.3.1 standard. 【0078】 According to another embodiment, the information relating to feeder link recovery may be provided via RRC messages (e.g., RRC connection reconfiguration messages) that are different from system information. For example, the information relating to feeder link recovery may be UE-specific. According to yet another embodiment, the information relating to feeder link recovery may be provided via MAC (medium access control) CE (control element). According to yet another embodiment, the information relating to feeder link recovery may be provided via DCI (downlink control information). 【0079】 2. Parameters The information relating to feeder link recovery may include one or more parameters. The information relating to feeder link recovery may be used to provide information about the recovery of a satellite (e.g., satellite 520) that provides NTN cells to a UE (e.g., UE 510) receiving the information. Therefore, the information relating to feeder link recovery may include information indicating the recovery time of satellite 520 and / or information required to predict the recovery time. 【0080】 According to one embodiment, the information relating to feeder link recovery may include information about a timer. For example, the timer information may indicate the length of the timer and / or the start time of the timer. UE510 can start the timer. For example, UE510 can start the timer in response to receiving the timer information. In another example, UE510 can start the timer at the start time indicated by the timer information. When the timer is running, UE510 can identify that the feeder link of satellite 520 is recoverable. The expiration of the timer may indicate the recovery of the feeder link of satellite 520. While the timer is running, UE510 can expect that the feeder link of satellite 520 is unavailable or will recover upon the expiration of the timer. If UE510 receives 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 recover, UE510 may cease operating the timer. For example, UE510 can activate a timer received from satellite 520. UE510 can then start the timer. As satellite 520 is positioned adjacent to a ground segment (e.g., NTN Gateway 530), the feeder link may become available. Meanwhile, the service link between UE510 and satellite 520 may become unavailable. As the timer expires, UE510 can identify that the feeder link of satellite 520 is available. Satellite 520 can then move along its orbit again. The feeder link may become unavailable. Satellite 520 can then reconnect with UE510 via signaling. Once UE510 is connected to satellite 520, it can restart the timer. UE510 can then determine that the feeder link is unavailable while the timer is operational.On the other hand, while UE510 is connected to satellite 520, satellite 520 can provide UE510 with information regarding the changed feeder link status. For example, satellite 520 may provide UE510 with another indicator if it is necessary to change the value of the timer or if it is difficult to operate the timer any further (for example, if recovery of the feeder link is unlikely to occur in the short term). Upon receiving this, UE510 may stop the timer or release the configured timer. 【0081】 According to one embodiment, the information related to feeder link recovery may include information about history. The information related to feeder link recovery can provide information about the history of satellite 520's connection to a ground segment (e.g., NTN gateway 530) within the orbit in which satellite 520 moves. For example, the information related to feeder link recovery may include information about PDU (packet data unit) sessions or EPS (evolved packet system) bearers associated with the cells of satellite 520. UE 510 can determine recoverability through the PDU sessions or EPS bearers associated with the cells 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 recover within a predetermined time. For example, UE510 can check the QCI (QoS Class identifier) ​​and, if the QCI is a predetermined value (e.g., a value indicating a delay-tolerant service or a service with a GBR (guaranteed bit rate) below a threshold), UE510 can identify that the feeder link of satellite 520 will recover within a predetermined time. UE510 can obtain time information related to the feeder link ID. UE510 can predict when the feeder link of satellite 520 will recover. For example, the information related to the feeder link recovery may include information about the ID of the feeder link connecting the cells of satellite 520 to the core network (e.g., core network 550). UE510 can obtain time information related to the feeder link ID. UE510 can predict when the feeder link of satellite 520 will recover. For example, the information related to the feeder link recovery may include the satellite ID or the ID of a core network entity located on the ground. For example, the ID of the core network entity may include the MME ID.Based on the geographical region where the MME ID is located and / or cell information about satellite 520 (e.g., celestial force information, orbital information), the UE510 can predict when the feeder link of satellite 520 will be restored. 【0082】 According to one embodiment, the information related to feeder link recovery may include spatial information. For example, the information related to feeder link recovery may include, as historical information of satellite 520, a tracking area, a location area, footprint information, service information, and / or celestial force information. 【0083】 In operation 703, satellite 520 may transmit one or more parameters for S&F mode to UE 510. According to one embodiment, UE 510 may perform a paging procedure in accordance with S&F mode while in an RRC idle state. A description of the paging procedure and the parameters associated with the paging procedure is described in detail via Figure 8a. According to one embodiment, UE 510 may perform a DRX operation in accordance with S&F mode. A description of the DRX operation and the parameters associated with the DRX operation is described in detail via Figure 8b. In this disclosure, the parameters for UE 510 in an RRC idle state in S&F mode are provided in signaling separate from the information related to feeder link recovery, but embodiments of this disclosure are not limited thereto. For example, the parameters in operation 703 may be transmitted together with the information related to feeder link recovery in operation 701. As an example, satellite 520 can send information related to feeder link recovery and parameters for UEs in an RRC idle state (e.g., parameters related to the paging procedure, parameters related to the DRX operation) to UE 510 via a single message (e.g., system information such as SIB32, RRC messages such as RRC reconfiguration messages). 【0084】 In operation 705, UE510 can predict the recovery time. In other words, UE510 can determine the expected recovery time. According to one embodiment, UE510 can determine the recovery time of the feeder link of satellite 520 based on information related to the recovery of the feeder link from satellite 520. According to one embodiment, UE510 can determine the recovery time of the feeder link of satellite 520 based on information related to the recovery of the feeder link from satellite 520 and parameters related to the DRX operation. For example, UE510 can determine that the feeder link of satellite 520 has recovered after a specified time after a DRX-on interval for the cells of satellite 520. The specified time can be indicated by satellite 520 or calculated in a predefined manner via DRX parameters (for example, determined as the period after 50% of a long DRX cycle). According to one embodiment, UE510 can determine the recovery time of the feeder link of satellite 520 based on information related to the recovery of the feeder link from satellite 520 and parameters related to the paging procedure. For example, after receiving a paging frame for a cell on satellite 520, UE510 may decide that the feeder link of satellite 520 will be restored after a specified time period from the time of the paging frame. The specified time period may be indicated by satellite 520 or calculated in a predefined manner via paging parameters (e.g., a range of 40% to 60% of the paging cycle). 【0085】 In operation 707, UE510 may perform a pre-operation. This pre-operation refers to an operation that UE510 performs in advance in anticipation of feeder link recovery. UE510 may be in an RRC idle state. 【0086】 UE510 can perform pre-operations if a recovery time is anticipated via operation 705. According to one embodiment, UE510 can perform further paging monitoring if the service link termination time is within a first threshold interval from the current time and the feeder link recovery time is within a second threshold period from the current time. By performing such paging monitoring, UE510 can attempt to maximize connectivity by increasing paging opportunities before the service link terminates. As a non-limiting example, UE510 can perform additional paging monitoring even if the service link termination time is within a first threshold interval from the current time or the feeder link recovery time is within a second threshold period from the current time. According to one embodiment, UE510 can set a shorter paging monitoring cycle if the service link termination time is within a first threshold interval from the current time and the feeder link recovery time is within a second threshold period from the current time. A shorter paging monitoring cycle may result in an increased number of paging monitoring operations per unit of time. As a non-limiting example, the UE510 can set a paging monitoring period shorter than the basic period even if the termination of a service link occurs within a first threshold interval from the current time, or if the recovery of a feeder link occurs within a second threshold period from the current time. 【0087】 According to one embodiment, the first threshold interval and / or the second threshold interval may be indicated by a network (e.g., satellite 520) (e.g., RRC message, MAC CE, DCI), determined depending on the celestial force information of satellite 520, or determined as a fixed value. 【0088】 UE510 can perform monitoring of paging messages from satellite 520 while in an RRC idle state. Parameters related to the paging messages and / or parameters related to the monitoring may be configured in UE510 by satellite 520. UE510 can attempt to establish a cell connection to perform possible services (e.g., delay-tolerant services, SMS services) over satellite 520's feeder link, as it is expected that the feeder link of satellite 520 will be restored. UE510 can perform a random access procedure with satellite 520 in response to receiving the paging messages. After the random access procedure, UE510 can operate in an RRC connected state. UE510 can transmit or receive data with satellite 520. For example, UE510 can provide uplink data (e.g., PUSCH) to satellite 520. Satellite 520 can store the uplink data. Once the feeder link is restored, the uplink data can be transmitted to other devices (e.g., servers, smartphones) over the feeder link and core network entities. 【0089】 According to one embodiment, UE510 can set an additional ON interval if the termination of the service link is within a first threshold interval from the current time, and the recovery of the feeder link is within a second threshold interval from the current time. Through the additional ON interval, UE510 can transmit more data to satellite 520. Information regarding the additional ON interval may be provided by satellite 520 as a tamia or cycle length. In one example, information regarding the additional ON interval may be received from a SIB or RRC message from satellite 520. In one example, information regarding the additional ON interval may be included in information related to feeder link recovery in operation 701 and / or one or more parameters for the S&F mode in operation 703. For example, UE510 can perform a DRX procedure with satellite 520. Parameters related to the DRX procedure may be configured by satellite 520 to UE510. UE510 can perform a DRX operation after establishing a connection with the satellite. DRX indicates that, as discontinuous reception, the UE510 repeatedly performs on and off intervals to conserve power. Since it is advantageous for the UE510 to transmit data considering the feeder link recovery time, the UE510 can decide whether to skip data transmission / reception during DRX on intervals based on the feeder link recovery time. As a non-limiting example, the UE510 can communicate with the network via additionally configured on intervals even if the service link termination time is within a first threshold interval from the current time, or the feeder link recovery time is within a second threshold interval from the current time. 【0090】 According to one embodiment, the UE510 can increase the connection priority to an NTN cell when a feeder link recovery is expected. For example, it can increase the priority information for the cell (e.g., "CellReselectionPriority" (see e.g., TS 36.304, TS 36.331)) or decrease the cell reselection threshold (e.g., ReselectionThreshold IE). According to one embodiment, the UE510 can perform a conditional handover when a feeder link recovery is expected and is expected to occur within a specified time. For example, the handover execution condition may be set based on parameters related to the feeder link recovery time. As a non-limiting example, the UE510 can select one or more cells indicated in the "whitelist Cell List" IE and perform a handover (e.g., a conditional handover) on the selected cell. 【0091】 Figure 8a shows an example of a paging procedure in S&F mode. Satellite 520 may be configured to perform the functions of an eNB. In one example, the eNB may be located on the board of satellite 520, and entities of the core network (e.g., core network 550) may be located on the ground. In one example, the eNB and some of the entities of the core network (or some of a specific entity (e.g., MME (mobile management entity))) may be located on the board of satellite 520, and other entities of the entities of the core network may be located on the ground. The same reference numbers may represent the application of the same description. 【0092】 Referring to Figure 8a, the UE510 can utilize DRX (discontinuous reception) to conserve power in the RRC idle state. A paging occasion (PO) represents a subframe that P-RNTI may transmit via the PDCCH (physical downlink control channel) that processes paging messages. A paging frame (PF) represents a radio frame and can contain one or more paging occasions. Using DRX, the UE510 can monitor only one paging occasion per DRX cycle (e.g., DRX cycle 810). For example, a radio frame (e.g., frame 821) within DRX cycle 810 may be a paging frame. For example, the paging frame for the UE510 may be frame 822. Frame 822 for the UE510 contains multiple paging occasions (e.g., paging occasion 831) as a paging frame, and the paging occasion for the UE510 may be paging occasion 832. When following the 3GPP standard, the paging frame can be determined based on the following formula: 【0093】 【number】 【0094】 Here, T represents the DRX cycle (e.g., 810 DRX cycles), N represents the smaller of T and nB (i.e., min(T, nB)), and nB may be composed of RRC. UE_ID represents the result of the modulo 1024 operation of the IMSI (International Mobile Subscriber Identity) value (UE_ID: IMSI mod 1024). 【0095】 When following the 3GPP standard, the pattern of paging occasions within a subframe can be determined based on the following formula: 【0096】 【number】 【0097】 Here, Ns represents max(1, nB / T). According to various embodiments of this disclosure, the UE510 can receive one or more parameters for a paging procedure from satellite 520. According to one embodiment, the one or more parameters for the paging procedure may include information about a paging cycle for S&F mode. The paging cycle may be used to separately identify the DRX cycle of the UE510 operating in S&F mode. In one example, the paging cycle may be referred to as the "T" value in [Equation 1]. Through the shorter period, the UE510 can perform paging monitoring. In non-limiting examples, additional paging for S&F mode may be performed preemptively in addition to the existing paging procedure. For example, when operating in S&F mode, if a service link failure is anticipated (e.g., a specified time before the service link becomes unavailable), the UE510 may perform a procedure for additional paging. The information about the specified time may be set from the network or be a fixed value. For example, when operating in S&F mode, if recovery of the service link is expected (for example, a specified time before the service link becomes available), the UE510 may perform additional paging procedures. The information regarding the specified time may be set from the network or be a fixed value. The paging cycle may represent a DRX period that includes the expected time of failure or recovery. According to one embodiment, the one or more parameters for the paging procedure may include information about paging occasions for S&F mode. For example, the information about paging occasions may include an "nB" value. In another example, the information about paging occasions may include parameters (e.g., offset, occasion number) for pointing to a paging occasion for performing additional paging. In a non-limiting example, additional paging for S&F mode may be performed preemptively in addition to the existing paging procedure. For example, when operating in S&F mode, if a service link failure is expected (e.g., a specified time before the service link becomes unavailable), the UE510 may perform a procedure for additional paging. For example, when operating in S&F mode, if a service link recovery is expected (e.g., a specified time before the service link becomes available), the UE510 may perform a procedure for additional paging. The UE510 may perform paging monitoring at the paging occasions indicated by the information about paging occasions. 【0098】 According to one embodiment, the one or more parameters for the paging procedure may include information about an identifier. The identifier may be used to identify the paging message of satellite 520 providing a cell that supports S&F mode. For example, the information about the identifier may include a P-RNTI for S&F mode. For example, the information about the identifier may include an identifier for S&F mode that is different from the P-RNTI. As a non-limiting example, additional paging for S&F mode may be performed preliminaryly in addition to the existing paging procedure. For example, when operating in S&F mode, if a service link unavailability is expected (e.g., a specified time before the service link becomes unavailable), UE510 may perform a connection attempt via a PDCCH masked with the identifier. As another example, when operating in S&F mode, if a service link recovery is expected (e.g., a specified time before the service link becomes available), UE510 may perform a connection attempt via a PDCCH masked with the identifier. 【0099】 According to one embodiment, the one or more parameters for the paging procedure may include information regarding the number of paging monitoring cycles. As satellite 520 moves, the service link between UE510 and satellite 520 in S&F mode may become inactive. The number of paging monitoring cycles (e.g., the number of paging occasions) may be set so that UE510 does not unnecessarily monitor paging messages from satellite 520 in the inactive state. After monitoring for the number of paging monitoring cycles for S&F, UE510 may maintain the RRC IDLE state for a predetermined time (e.g., the orbital period of satellite 520 minus the offset time). The offset time may represent the time that satellite 520 is connected to UE510 in S&F mode. The predetermined time may be determined by UE510 or set by the network (e.g., satellite 520). The offset time may be determined by UE510 or set by the network (e.g., satellite 520). Subsequently, after the predetermined time, the UE510 can perform paging monitoring again, as recovery of the service link is expected. 【0100】 According to one embodiment, the one or more parameters for the paging procedure may include information regarding the number of pre-paging monitoring cycles. Depending on the S&F mode, the service link between UE510 and satellite 520 may repeatedly recover and become unrecoverable. From some point before the service link recovers, UE510 may perform further paging monitoring. To ensure that the paging cycle does not delay the resumption of communication between UE510 and satellite 520, UE510 may perform further pre-paging procedures. The pre-paging procedures may be performed for each paging cycle and may indicate the number of additional paging occasions to be performed in addition to the paging occasions within that paging cycle according to predefined parameters. 【0101】 Figure 8b shows an example of DRX (discontinuous reception) operation in S&F mode. Satellite 520 may be configured to perform the functions of an eNB. In one example, the eNB may be located on the board of satellite 520, and entities of the core network (e.g., core network 550) may be located on the ground. In one example, the eNB and some of the entities of the core network (or some of a specific entity (e.g., MME (mobile management entity))) may be located on the board of satellite 520, and other entities of the core network may be located on the ground. The same reference numbers may represent the application of the same description. 【0102】 Referring to Figure 8b, the UE510 can utilize DRX (discontinuous reception) to conserve power in the RRC idle state. The UE510 can periodically switch between active and inactive states to reduce battery consumption. In the active state (i.e., on-duration), the UE510 receives or transmits data from the network (e.g., satellite 520), and in the inactive state, it conserves power by minimizing latency. For example, in the active state, the UE510 can turn on the RF unit, and in the inactive state, the UE510 can turn off the RF unit. The UE510 can transmit or receive data packets in the active state 851 of the RRC connected state. The UE510 can restart the inactive timer each time it transmits or receives a data packet. When the inactive timer expires, the UE510 can transition to the DRX mode 852 of the RRC connected state. The UE510 can be activated and perform communication at each short DRX cycle. The interval in which the UE510 transmits or receives signals may be referred to as an ON interval. When the DRX short cycle timer expires, the UE510's DRX repetition cycle (the cycle of changing between active and inactive states) may change from a short DRX cycle to a long DRX cycle. If the UE510 receives data during the active state due to the DRX cycle (for example, when decoding a PDCCH), the UE510 can exit DRX mode and operate again in the active state 853. If there is a prolonged period of no data transmission or reception in the DRX mode or active state 853 during the RRC connection state, the UE510 may transition to the RRC idle state 854. The UE510 can also perform DRX operations in the RRC idle state 854. The DRX operation in the RRC idle state 854 may be referred to as the paging monitoring procedure illustrated via Figure 8a. 【0103】 According to various embodiments of this disclosure, UE510 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 regarding the on-duration for the S&F mode. For example, the on-duration information may represent a time interval corresponding to an active state within the DRX cycle. The on-duration information may include a value corresponding to the number of subframes. As an example, if recovery of the service link is expected, it is advantageous to increase the time of the active state, so the on-duration information for S&F mode may be set to a value longer than the on-duration for a typical DRX (i.e., configured for ground station and UE communication). As another example, since it is not necessary to operate in an active state after the service link has terminated, the on-duration information for S&F mode may be set to a value longer than the on-duration for a typical DRX (i.e., configured for ground station and UE communication). The aforementioned parameters, as on-intervals separately configured for S&F mode, ensure sufficient active state throughout the on-interval when the service link termination time is imminent (e.g., within a first threshold period) or the service link recovery time is imminent. In S&F mode, the effective active time during which UE510 can communicate with satellite 520 can be improved. In a non-limiting example, instead of being configured separately from the general DRX on-interval, an additional time to maintain an active state may be configured for UE510 as a parameter for the DRX, in addition to the general DRX on-interval. 【0104】 According to one embodiment, the one or more parameters for the DRX may include information regarding a DRX inactivity timer for S&F mode. From the perspective of the UE510 operating in S&F mode, it may be advantageous to maintain the active state for as long as possible before the service link terminates to improve data transmission efficiency. Furthermore, from the perspective of the UE510, maintaining the active state before the service link is restored may be advantageous from the standpoint of transmission efficiency, because when the service link is unavailable, the UE510 does not need to utilize the RF unit in the first place. The information regarding the DRX inactivity timer for S&F mode may be set to a longer value than a typical DRX inactivity timer (i.e., configured for ground base station and UE communication). The parameter is a timer separately set for S&F mode, and when the service link termination time is imminent (e.g., within a first threshold period), the active state of the UE510 can be sufficiently ensured by delaying the transition to DRX mode as much as possible. As a non-limiting example, instead of setting a separate general DRX inactive timer, an additional offset that maintains the active state may be configured in the UE510 as a parameter for the DRX, in addition to the general DRX inactive timer. 【0105】 According to one embodiment, the one or more parameters for the DRX may include information regarding the DRX cycle length for the S&F mode. A longer DRX cycle length is advantageous for the UE510 in terms of battery saving. Conversely, a shorter DRX cycle length may be advantageous for the UE510 in terms of transmission efficiency, as it will transition to the active state at shorter intervals. For example, from the perspective of the UE510 operating in S&F mode, it may be advantageous to increase the frequency of the active state and improve data transmission efficiency when service link recovery is expected. For example, from the perspective of the UE510, it may be advantageous in terms of transmission efficiency to maintain the active state before the service link is recovered. The information regarding the DRX cycle length for the S&F mode may be set to a value shorter than the general (i.e., configured for ground base station and UE communication) DRX cycle length. As a non-limiting example, instead of setting a general DRX cycle length separately, a separate offset may be configured for the UE510 as a parameter for the DRX in addition to the general DRX cycle length. 【0106】 According to one embodiment, the one or more parameters for the DRX may include information regarding the DRX short-cycle timer for the S&F mode. From the perspective of the UE510 operating in S&F mode, it may be advantageous to maintain the active state for as long as possible before the service link terminates to improve data transmission efficiency, since the UE510 does not need to use the RF unit in the first place when the service link is unavailable. However, since the DRX short-cycle timer is used for transitioning to the DRX long cycle, it is advantageous from the viewpoint of transmission efficiency for the UE510 to transition to the DRX long cycle when the service link is unavailable. The information regarding the DRX short-cycle timer for the S&F mode may be set to a longer value than a typical DRX short-cycle timer (i.e., configured for ground base station and UE communication). The parameter, as a timer separately set for S&F mode, can ensure that the active state of the UE510 is sufficiently maintained by delaying the transition to the DRX long cycle as much as possible when the service link termination time is imminent (e.g., within a first threshold period). As a non-limiting example, instead of setting a separate general DRX short-cycle timer, an additional offset that maintains an active state may be configured in the UE510 as a parameter for the DRX, in addition to the general DRX short-cycle timer. 【0107】 According to one embodiment, the one or more parameters for DRX may include information indicating whether or not DRX is supported in S&F mode. For example, whether or not DRX is supported in S&F mode may be configured in UE510 as separate information. The DRX configuration information may include information about DRX in S&F mode. If the information about DRX in S&F mode indicates that it is enabled, the parameters for S&F mode may be configured in UE510 separately from the general DRX parameters (i.e., configured for ground base station and UE communication). If the information about DRX in S&F mode indicates that it is disabled, UE510 may reuse the general DRX parameters for S&F mode. 【0108】 Figure 9 shows an example of the components of a UE (e.g., UE510). 【0109】 Referring to Figure 9, the UE510 may include a transceiver 901, a processor 903, and memory 905. The transceiver 901 performs the function of sending and receiving signals over a radio channel. For example, the transceiver 901 upconverts a baseband signal to an RF band signal and transmits it via an antenna, and downconverts the RF band signal received via the antenna back to a baseband signal. 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. 【0110】 The transceiver 901 may include multiple transmit / receive paths. Furthermore, the transceiver 901 may include an antenna section. The transceiver 901 may include at least one antenna array composed of multiple antenna elements. From a hardware perspective, the transceiver 901 may consist of digital and analog circuits (e.g., an RFIC (radio frequency integrated circuit)). Here, the digital and analog circuits may be implemented as a single package. Furthermore, the transceiver 901 may include multiple RF chains. The transceiver 901 can perform beamforming. The transceiver 901 may apply beamforming weights to signals to impart directionality to the signals to be transmitted or received according to the settings of the processor 903. According to one embodiment, the transceiver 901 may include an RF (radio frequency) block (or RF section). According to one embodiment, the transceiver 901 can support satellite communications. The UE 510 can transmit signals to or receive signals from a satellite (e.g., satellite 520) via the transceiver 901. 【0111】 The transceiver 901 can transmit and receive signals over a radio access network. For example, the transceiver 901 can receive downlink signals. Downlink signals may include synchronization signals (SS), reference signals (RS) (e.g., CRS (cell-specific reference signal), DM (demodulation)-RS), system information (e.g., MIB, SIB, RMSI (remaining system information), OSI (other system information)), configuration messages, control information, or downlink data. Furthermore, for example, the transceiver 901 can transmit uplink signals. The uplink signal may include random access-related signals (e.g., random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), reference signals (e.g., SRS (sounding reference signal), DM-RS), uplink control information (UCI) (e.g., CSI (channel state information), HARQ (hybrid automatic repeat request), SR (scheduling request)), or power headroom reports (PHR). Although only the transceiver 901 is shown in Figure 9, according to another embodiment, the UE510 may include two or more RF transceivers. 【0112】 The processor 903 controls the overall operation of the UE510. The processor 903 may be referred to as the control unit. For example, the processor 903 transmits and receives signals via the transceiver 901. The processor 903 also writes and reads data to and from the memory 905. Furthermore, the processor 903 can perform the functions of the protocol stack required by the communication standard. Although only the processor 903 is shown in Figure 9, according to another embodiment, the UE510 may include two or more processors. The processor 903 may be an instruction / code or memory area storing instructions / code that resides at least temporarily in the processor 903 as an instruction set or code stored in the memory 905, or it may be part of the circuitry that constitutes the processor 903. In addition, the processor 903 may include various modules for performing communication. The processor 903 can control the UE510 to perform the operations according to the embodiment. 【0113】 Memory 905 stores data such as basic programs, application programs, and configuration information for the operation of the UE510. Memory 905 may be referred to as a storage unit. Memory 905 may consist of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Memory 905 then provides the stored data in response to requests from processor 903. According to one embodiment, memory 905 may include memory for conditions, instructions, or settings related to satellite communication transmission schemes. 【0114】 Figure 10 shows an example of the components of a satellite (e.g., satellite 520). 【0115】 Referring to Figure 10, satellite 520 may include at least one transceiver 1001, at least one processor 1003, and at least one memory 1005. Hereafter, components are described singly, but implementations of multiple components or subcomponents are not excluded. 【0116】 The transceiver 1001 performs the function of transmitting and receiving signals via a wireless channel. For example, the transceiver 1001 performs the function of converting between baseband signals and bit sequences according to the system's physical layer standard. For example, when transmitting data, the transceiver 1001 generates complex symbols by encoding and modulating the transmitted bit sequence. When receiving data, the transceiver 1001 demodulates and decodes the baseband signal to restore the received bit sequence. The transceiver 1001 also upconverts the baseband signal to an RF (radio frequency) band signal and transmits it via the antenna, and downconverts the RF band signal received via the antenna back to a baseband signal. For this purpose, the transceiver 1001 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. Furthermore, the 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 consist of a digital unit and an analog unit, and the analog unit may consist of 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 the "transmitting unit," the "receiving unit," or the "transmitting / receiving unit." 【0117】 The transceiver 1001 does not exclude the ability to transmit or receive signals not only via wireless channels but also via backhaul networks, optical communications, Ethernet, and other wired paths. For example, the transceiver 1001 can support optical communications for satellite 520 to signal with other satellites. Satellite 520 can communicate with other satellites using optical communications by using lasers via the transceiver 1001. For example, wired communications between components within satellite 520 may be supported. The transceiver 1001 can convert bit streams transmitted to other nodes in satellite 520, such as other connection nodes, other base stations, higher-level nodes, core networks, etc., into physical signals, and can convert physical signals received from other nodes into bit streams. 【0118】 The transceiver 1001 can support communication between satellite 520 and UE 510. The transceiver 1001 can support communication not only between satellite 520 and UE 510, but also between satellite 520 and the ground segment (e.g., NTN gateway 530, network entities of core network 550). As a non-limiting example, circuits for communication with UE 510 and circuits for communication with the ground segment (e.g., NTN gateway 530, network entities of core network 550) can be distinguished within the transceiver 1001. 【0119】 The processor 1003 can control the overall operation of the satellite 520. For example, the processor 1003 writes to and reads data from the memory 1005. For example, the processor 1003 transmits and receives signals via the transceiver 1001. Figure 10 shows one processor, but embodiments of the present disclosure are not limited thereto. The satellite 520 may include at least one processor (e.g., multiple processors) to perform embodiments of the present disclosure. The processor 1003 may be referred to as a control unit or control means. According to embodiments of the present disclosure, the processor 1003 can control the satellite 520 to perform at least one of the operations or methods according to embodiments of the present disclosure. 【0120】 Memory 1005 can store data such as basic programs, application programs, and configuration information for the operation of satellite 520. Memory 1005 can store various data used by at least one component (e.g., transceiver 1001, processor 1003). The data may include, for example, software and input or output data for related instructions. Memory 1005 may consist of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Memory 1005 can then provide the stored data to the processor 1003 upon request. 【0121】 Embodiments of this disclosure provide a satellite device for providing NTN (non-terrestrial network) access. The device 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 device may cause a message to be sent to a user equipment (UE) containing information related to store and forward (S&F) mode, and to communicate with the UE 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 regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. 【0122】 For example, the message may include at least one of the following: information regarding the paging cycle for the S&F mode, information regarding the paging frame for the S&F mode, information regarding the paging occasion for the S&F mode, information regarding the number of paging monitorings for the S&F mode, or information regarding the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. 【0123】 For example, the message may include at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. 【0124】 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, or information regarding event trigger conditions for the S&F mode. 【0125】 For example, the message may include information about a first subsequent satellite that provides service to the first footprint of the satellite, and information about a second subsequent satellite that provides service to the second footprint of the target satellite. 【0126】 Embodiments of this disclosure provide user equipment (UE) for performing NTN (non-terrestrial network) access. The UE may include memory containing instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the UE may receive a message from a satellite configured to perform evolved node B (eNB) functions, containing information related to store and forward (S&F) mode, and based on the message, initiate communication with the satellite. The message may include at least one of the following: information indicating that the satellite supports the S&F mode; information regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. 【0127】 For example, the message may include at least one of the following: information regarding the paging cycle for the S&F mode, information regarding the paging frame for the S&F mode, information regarding the paging occasion for the S&F mode, information regarding the number of paging monitorings for the S&F mode, or information regarding the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. 【0128】 For example, the message may include at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. 【0129】 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, or information regarding event trigger conditions for the S&F mode. 【0130】 For example, the message may include information about a first subsequent satellite that provides service to the first footprint of the satellite, and information about a second subsequent satellite that provides service to the second footprint of the target satellite. 【0131】 Embodiments of this disclosure provide a method performed by a satellite for providing NTN (non-terrestrial network) access. This method may include sending a message to a user equipment (UE) containing information related to store and forward (S&F) mode, and communicating with the UE 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 regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. 【0132】 For example, the message may include at least one of the following: information regarding the paging cycle for the S&F mode, information regarding the paging frame for the S&F mode, information regarding the paging occasion for the S&F mode, information regarding the number of paging monitorings for the S&F mode, or information regarding the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. 【0133】 For example, the message may include at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. 【0134】 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, or information regarding event trigger conditions for the S&F mode. 【0135】 For example, the message may include information about a first subsequent satellite that provides service to the first footprint of the satellite, and information about a second subsequent satellite that provides service to the second footprint of the target satellite. 【0136】 Embodiments of this disclosure provide a method performed by user equipment (UE) for performing NTN (non-terrestrial network) access. This method may include receiving a message from a satellite configured to perform evolved node B (eNB) functions, the message containing information related to store and forward (S&F) mode, and communicating 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 regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. 【0137】 For example, the message may include at least one of the following: information regarding the paging cycle for the S&F mode, information regarding the paging frame for the S&F mode, information regarding the paging occasion for the S&F mode, information regarding the number of paging monitorings for the S&F mode, or information regarding the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. 【0138】 For example, the message may include at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. 【0139】 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, or information regarding event trigger conditions for the S&F mode. 【0140】 For example, the message may include information about a first subsequent satellite that provides service to the first footprint of the satellite, and information about a second subsequent satellite that provides service to the second footprint of the target satellite. 【0141】 The methods described in the claims or specifications of this disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. 【0142】 When implemented as software, a computer-readable storage medium containing one or more programs (software modules) may be provided. The one or more programs stored on the computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to perform the methods according to the claims or specifications of this disclosure. 【0143】 Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage devices, compact disc-ROMs (CD-ROMs), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes, or in memory composed of some or all of these. Furthermore, each constituent memory may include multiple instances. 【0144】 Furthermore, the program may be stored in an attachable storage device that is accessible via a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), SAN (storage area network), or a combination thereof. Such a storage device may be connected via an external port to an apparatus performing an embodiment of the disclosure. In addition, a separate storage device on the communication network may also be connected to an apparatus performing an embodiment of the disclosure. 【0145】 In the specific embodiments of the present disclosure described above, the components included in the disclosure are represented singly or plurally according to the particular embodiment presented. However, the singly or plural representations are selected for the purposes of the present context, and the disclosure is not limited to singly or plural components. Components represented plural may consist of singular components, and components represented singly may consist of plural components. 【0146】 While specific embodiments have been described in the detailed description of this disclosure, it goes without saying that various modifications are possible as long as they do not deviate from the scope of this disclosure.

Claims

[Claim 1] In satellite equipment for providing NTN (non-terrestrial network) access, Memory containing instructions; at least one processor; and Includes at least one transceiver, When the instruction is executed by the at least one processor, the device: A message containing information related to the S&F (store and forward) mode is sent to the UE (user equipment). Based on the aforementioned message, it is triggered to initiate communication with the UE, The device wherein the message includes at least one of the following: information indicating that the satellite supports the S&F mode; information regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. [Claim 2] The apparatus according to claim 1, wherein the message includes at least one of the following: information relating to a paging cycle for the S&F mode, information relating to a paging frame for the S&F mode, information relating to a paging occasion for the S&F mode, information relating to the number of paging monitorings for the S&F mode, or information relating to a P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. [Claim 3] The apparatus according to claim 1, wherein the message includes at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. [Claim 4] The apparatus according to claim 1, wherein the message includes 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, the cell selection parameter for the S&F mode, or the information regarding the event trigger condition for the S&F mode. [Claim 5] The apparatus according to claim 1, wherein the message includes information about a first subsequent satellite providing service to a first footprint of the satellite and information about a second subsequent satellite providing service to a second footprint of the target satellite. [Claim 6] In user equipment (UE) for performing NTN (non-terrestrial network) access, Memory containing instructions; at least one processor; and Includes at least one transceiver, When the instruction is executed by the at least one processor, the UE: A message containing information related to the S&F (store and forward) mode is received from a satellite configured to perform the functions of an evolved node B (eNB). Based on the aforementioned message, it triggers communication with the satellite, The message includes at least one of the following: information indicating that the satellite supports the S&F mode; information regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. [Claim 7] The UE according to claim 6, wherein the message includes at least one of the following: information relating to the paging cycle for the S&F mode, information relating to the paging frame for the S&F mode, information relating to the paging occasion for the S&F mode, information relating to the number of paging monitorings for the S&F mode, or information relating to the P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. [Claim 8] The UE according to claim 6, wherein the message includes at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. [Claim 9] The UE according to claim 6, wherein the message includes 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, the cell selection parameter for the S&F mode, or information regarding the event trigger condition for the S&F mode. [Claim 10] The UE according to claim 6, wherein the message includes information about a first subsequent satellite providing service to a first footprint of the satellite and information about a second subsequent satellite providing service to a second footprint of the target satellite. [Claim 11] In a method implemented by satellite to provide NTN (non-terrestrial network) access, The operation of sending a message to the UE (user equipment) containing information related to the S&F (store and forward) mode, This includes an operation to communicate with the UE based on the aforementioned message, A method wherein the message includes at least one of the following: information indicating that the satellite supports the S&F mode; information regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. [Claim 12] The method according to claim 11, wherein the message includes at least one of the following: information relating to a paging cycle for the S&F mode, information relating to a paging frame for the S&F mode, information relating to a paging occasion for the S&F mode, information relating to the number of paging monitorings for the S&F mode, or information relating to a P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. [Claim 13] The method according to claim 11, wherein the message includes at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. [Claim 14] The method according to claim 11, wherein the message includes 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, the cell selection parameter for the S&F mode, or information regarding the event trigger condition for the S&F mode. [Claim 15] The method according to claim 11, wherein the message includes information about a first subsequent satellite that provides service to a first footprint of the satellite and information about a second subsequent satellite that provides service to a second footprint of the target satellite. [Claim 16] In a method performed by user equipment (UE) for NTN (non-terrestrial network) access, The operation of receiving a message containing information related to the S&F (store and forward) mode from a satellite configured to perform the functions of an eNB (evolved node B), This includes an action to communicate with the satellite based on the aforementioned message, A method wherein the message includes at least one of the following: information indicating that the satellite supports the S&F mode; information regarding the validity period of the service link between the UE and the satellite in the S&F mode; information regarding the validity period of the feeder link between the satellite and the NTN gateway in the S&F mode; celestial force information of the satellite; footprint information provided by the satellite; or information regarding a list of neighboring cells that support the S&F mode. [Claim 17] The method according to claim 16, wherein the message includes at least one of the following: information relating to a paging cycle for the S&F mode, information relating to a paging frame for the S&F mode, information relating to a paging occasion for the S&F mode, information relating to the number of paging monitorings for the S&F mode, or information relating to a P-RNTI (paging radio network temporary identifier) ​​for the S&F mode. [Claim 18] The method according to claim 16, wherein the message includes at least one of the following: information regarding the DRX (discontinuous reception) on-duration for the S&F mode; information regarding the DRX retransmission timer for the S&F mode; information regarding the DRX inactivity timer for the S&F mode; information regarding the DRX cycle length for the S&F mode; information regarding the DRX short cycle timer for the S&F mode; or information indicating whether or not DRX is supported in the S&F mode. [Claim 19] The method according to claim 16, wherein the message includes 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, the cell selection parameter for the S&F mode, or information regarding the event trigger condition for the S&F mode. [Claim 20] The method according to claim 16, wherein the message includes information about a first subsequent satellite that provides service to a first footprint of the satellite and information about a second subsequent satellite that provides service to a second footprint of the target satellite.

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