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

Abstract

An apparatus and method for a satellite for providing non-terrestrial network access, a user equipment and method for performing non-terrestrial network access, the apparatus comprising: a memory storing instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the apparatus is configured to: in a radio resource control connected state with the user equipment, identify a store-and-forward mode, transmit, to the UE, a message indicating that the satellite acts in the S&F mode, after transmitting the message, receive, from the UE, a request signal related to releasing the RRC connection, and transmit, to the UE, an RRC connection release message for releasing the RRC connection. The RRC connection release message contains a cause value for releasing the RRC connection. The message contains at least one of an indicator indicating that a cell provided by the satellite supports the S&F mode, information related to a validity time of a feeder link of the satellite, and information related to a condition for triggering the request for releasing the RRC connection.

Description

Technical Field

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

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

[0003] According to embodiments of this disclosure, an apparatus is provided for providing access to a satellite for a non-terrestrial network (NTN), the satellite being configured to perform the functions of an enhanced node B (eNB). The apparatus may include: a memory containing instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the apparatus may be configured to: identify a store-and-forward (S&F) mode in a radio resource control (RRC) connection state with user equipment (UE), transmit a message to the UE indicating that the satellite is operating in the S&F mode, and after transmitting the message, receive a request signal from the UE related to terminating the RRC connection, and transmit an RRC connection termination message to the UE for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may include at least one of the following: an indicator indicating that the cell provided by the satellite supports S&F mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering a request to terminate the RRC connection.

[0004] According to embodiments of this disclosure, a user equipment (UE) is provided for performing non-terrestrial network (NTN) access. The UE may include: a memory including instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the UE may be configured to: receive, in a radio resource control (RRC) connection state, a message from a satellite configured to perform enhanced node B (eNB) functions indicating that the satellite is operating in store-and-forward (S&F) mode; after receiving the message, transmit a request signal related to terminating the RRC connection to the satellite; and receive an RRC connection termination message from the satellite for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may contain at least one of the following: an indicator indicating that the cell provided by the satellite supports S&F mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering the request to terminate the RRC connection.

[0005] According to embodiments of this disclosure, a method is provided for providing access to a non-terrestrial network (NTN) by a satellite configured to perform the functions of an enhanced node B (eNB). The method may include: identifying a store-and-forward (S&F) mode while in a radio resource control (RRC) connection state with user equipment (UE); transmitting a message to the UE indicating that the satellite is operating in the S&F mode; receiving, after transmitting the message, a request signal from the UE related to terminating the RRC connection; and transmitting an RRC connection termination message to the UE for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may contain at least one of the following: an indicator indicating that the cell provided by the satellite supports the S&F mode, information related to the validity period of the satellite's feeder link, and information related to conditions for triggering the termination of the RRC connection.

[0006] According to embodiments of this disclosure, a method is provided performed by user equipment (UE) for performing non-terrestrial network (NTN) access. The method may include: receiving, while in a radio resource control (RRC) connection state, a message from a satellite configured to perform enhanced node B (eNB) functions, indicating that the satellite is operating in store-and-forward (S&F) mode; transmitting, after receiving the message, a request signal related to terminating the RRC connection to the satellite; and receiving, from the satellite, an RRC connection termination message for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may contain at least one of the following: an indicator indicating that the cell provides S&F mode support by the satellite, information related to the validity period of the satellite's feeder link, and information related to conditions for triggering the request to terminate the RRC connection. Attached Figure Description

[0007] Figure 1 A wireless communication system is shown.

[0008] Figure 2A and Figure 2B An example of a non-terrestrial network (NTN) is shown.

[0009] Figure 3A An example of a control plane (C-plane) is shown.

[0010] Figure 3B An example of a user plane (U-plane) is shown.

[0011] Figure 4 An example of the resource structure in the time-frequency domain of a wireless communication system is shown.

[0012] Figure 5 This illustrates an example of the store-and-forward (S&F) mode in a non-terrestrial network (NTN) for the Internet of Everything (IoT).

[0013] Figure 6 Signaling that displays information related to the effective time of the S&F mode.

[0014] Figure 7 This example illustrates the RRC (radio resource control) connection status of an IoT UE (user equipment).

[0015] Figure 8A This example illustrates how to disconnect an RRC connection in S&F mode.

[0016] Figure 8B This example illustrates a request to terminate an RRC connection in S&F mode.

[0017] Figure 9 Examples of the constituent elements of a UE are shown.

[0018] Figure 10 Examples of the components of a satellite are shown. Detailed Implementation

[0019] The terminology used in this disclosure is for illustrative purposes only and is not intended to limit the scope of other embodiments. Singular expressions include plural expressions unless a different meaning is explicitly indicated in the context. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art as described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of related art, and should not be construed as having an ideal or overly formal meaning unless explicitly defined in this disclosure. Depending on the circumstances, even terms defined in this disclosure should not be construed as excluding embodiments of this disclosure.

[0020] The various embodiments of this disclosure described below are illustrated using hardware-based approach methods. However, since the various embodiments of this disclosure include techniques that use both hardware and software, software-based approach methods are not excluded.

[0021] The terms used in the following description referring to signals (e.g., signal, information, message, signaling), resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), opportunity) (e.g., step, operation, procedure) (e.g., data packet, user stream, information, bit, symbol, codeword) (e.g., data packet, user stream, information, bit, symbol, codeword) (e.g., data packet, user stream, information, symbol, codeword) (e.g., data packet, user stream, information, symbol, codeword) (e.g., data packet, user stream, information, symbol, codeword) (e.g., data packet, user stream, information, information, symbol, codeword) (e.g., data packet, user stream ...

[0022] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, "physical downlink shared channel" (PDSCH) is a term referring to the physical channel through which data is transmitted, but PDSCH can also be used to refer to data. That is, in this disclosure, the expression "transmitting physical channel" can be interpreted as equivalent to the expression "transmitting data or signals through physical channel."

[0023] In the following disclosure, upper-level signaling refers to a signal transmission method in which a base station transmits signals to a terminal using the downlink data channel of the physical layer, or in which a terminal transmits signals to a base station using the uplink data channel of the physical layer. Upper-level signaling can be understood as radio resource control (RRC) signaling or MAC control element (hereinafter referred to as "CE").

[0024] Furthermore, in this disclosure, the expressions "above" or "below" may be used to determine whether a specific condition is satisfied or fulfilled. However, this is merely for illustrative purposes and is not intended to exclude statements of "above" or "below". A condition described as "above" may be replaced by "above", a condition described as "below" may be replaced by "below", and a condition described as "above and below" may be replaced by "above and below". Additionally, "A" to "B" hereafter represent at least one of the elements from A (inclusive) to B (inclusive). "C" and / or "D" hereafter represent at least one of "C" or "D", that is, including {"C", "D", "C and "D"}.

[0025] In this disclosure, signal quality can be, for example, at least one of the following: reference signal received power (RSRP), beam reference signal received power (BRSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal to interference and noise ratio (SINR), carrier to interference and noise ratio (CINR), signal to noise ratio (SNR), error vector magnitude (EVM), bit error rate (BER), and block error rate (BLER). Besides the examples above, other terms or metrics with equivalent technical meanings may be used. Hereinafter, in this disclosure, high signal quality means a large signal quality value associated with signal magnitude or a small signal quality value associated with error rate. Higher signal quality indicates a smoother wireless communication environment. Furthermore, the optimal beam refers to the beam with the highest signal quality among the beams.

[0026] This disclosure uses terminology used in some communication specifications (e.g., the 3rd Generation Partnership Project, 3GPP, and the European Telecommunications Standards Institute, ETSI) to illustrate various embodiments, but this is merely illustrative. The various embodiments of this disclosure can be readily modified and applied in other communication systems.

[0027] Figure 1 A wireless communication system is shown.

[0028] Reference Figure 1 , Figure 1 It is a wireless interface for Radio Access Technology (RAT), and terminal 110 and base station 120 are illustrated as part of a node utilizing a wireless channel in a wireless communication system using the evolved UMTS (Universal Mobile Telecommunications System) radio access network (EUTRAN) or New Radio (NR). Although Figure 1 Only one base station is shown, but the wireless communication system may also include other base stations that are the same as or similar to the base station (e.g., LTE eNB or NR gNB) 120.

[0029] Terminal 110 is a user-operated device that communicates with base station 120 via a wireless channel. In base station 120, the link towards terminal 110 is called the downlink (DL), and the link from terminal 110 towards base station 120 is called the uplink (UL). Furthermore, although not in... Figure 1 As shown, terminal 110 and other terminals can communicate via their respective wireless channels. In this case, the device-to-device (D2D) link between terminal 110 and other terminals is called a sidelink, which can be used interchangeably with the PC5 interface. In other embodiments, terminal 110 can be operated independently of the user. According to one embodiment, terminal 110 is a device performing machine-type communication (MTC) and can be carried by the user. Furthermore, according to one embodiment, terminal 110 can be an NB (narrowband)-IoT (internet of things) device.

[0030] In the process of describing the system and method in this specification, terminal 110 may be an electronic device used to communicate with base station 120 for voice and / or data communication, and base station 120 may communicate with the network of the device (e.g., public switched telephone network (PSTN), Internet, etc.).

[0031] Furthermore, in addition to being called a terminal, the terminal 110 may also be referred to as "user equipment (UE)," "vehicle," "customer premises equipment (CPE)," "mobile station," "subscriber station," "remote terminal," "wireless terminal," "electronic device," "user device," "access terminal," "mobile terminal," "remote station," "user terminal," "subscriber unit," "mobile device," or other terms with equivalent technical meanings.

[0032] Furthermore, examples of terminal 110 include cellular phones, smartphones, personal portable information terminals (e.g., personal digital assistants (PDAs)), laptops, network laptops, e-readers, wireless modems, etc. In the 3GPP specification, terminal 110 is typically referred to as a UE. However, since the scope disclosed in this specification should not be limited by the 3GPP standard, the terms "UE" and "terminal" are used interchangeably in this specification to refer to the more conventional term "wireless communication device." A UE can also be more conventionally referred to as a terminal device.

[0033] Base station 120 is the network infrastructure that provides wireless access to terminal 110. Base station 120 has a coverage area defined based on the distance at which signals can be transmitted. In 3GPP specifications, base station 120 is generally referred to as "Node B", "Enhanced Node B (eNodeB, eNB)", "5th generation node", "Next generation node B (gNB)", "Home Enhanced Node B (HeNB)", or other terms with equivalent technical meanings, such as "access point (AP)", "wireless point", "transmission / reception point (TRP)".

[0034] Because the scope of the disclosures in this specification should not be limited by 3GPP standards, the terms "base station," "node B," "eNB," and "HeNB" are used interchangeably in this specification to refer to the more conventional term "base station." Furthermore, the term "base station" can be used to refer to an access point. An access point can be an electronic device that provides access to a network used for wireless communication equipment (e.g., a local area network (LAN), the Internet, etc.). The term "communication equipment" can be used to refer to both wireless communication equipment and / or a base station. eNB or gNB can also be more conventionally referred to as base station equipment.

[0035] Base station 120 can communicate with core network entity 130. For example, core network entity 130 may include a mobility management entity (MME) responsible for control plane functions such as terminal 110 access and mobility control functions, and a serving gateway (S-GW) responsible for control functions for user data.

[0036] Terminal 110 can perform beamforming with base station 120. Terminal 110 and base station 120 can transmit and receive wireless signals in relatively low frequency bands (e.g., FR 1 in NR). Furthermore, terminal 110 and base station 120 can transmit and receive wireless signals in relatively high frequency bands (e.g., FR 2 in NR (or FR 2-1, FR 2-2, FR 2-3, FR 3), and millimeter-wave (mmWave) bands (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz)). To improve channel gain, terminal 110 and base station 120 can perform beamforming. Here, beamforming can include transmit beamforming and / or receive beamforming. Terminal 110 and base station 120 can impart directivity to the transmitted or received signals. Therefore, terminal 110 and base station 120 can select a serving beam through beam search or beam management steps. After selecting the serving beam, subsequent communication can be performed through resources that have a QCL (Quasi Co-Location) relationship with the resource that transmits the serving beam.

[0037] If the large-scale characteristics of the channel for transmitting symbols at the first antenna port can be inferred from the channel for transmitting symbols at the second antenna port, then the first and second antenna ports can be evaluated as having a QCL relationship. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receiver parameter.

[0038] Both terminal 110 and base station 120 can perform beamforming, but the embodiments of this disclosure are not limited thereto. In some embodiments, terminal 110 may or may not perform beamforming. Furthermore, base station 120 may or may not perform beamforming. That is, only one of terminal 110 and base station 120 may perform beamforming, or neither terminal 110 nor base station 120 may perform beamforming.

[0039] In this disclosure, a beam refers to the spatial flow of signals in a wireless channel, formed by one or more antennas (or antenna elements), a process known as beamforming. Beamforming can include at least one of analog beamforming or digital beamforming (e.g., precoding). Reference signals transmitted based on beamforming can include, for example, demodulation-reference signals (DM-RS), channel state information-reference signals (CSI-RS), synchronization signal / physical broadcast channel (SS / PBCH), and sounding reference signals (SRS). Furthermore, as a configuration of each reference signal, information elements (IEs) such as CSI-RS resources or SRS resources can be used, and such configurations can include beam-associated information. Information associated with the beam can indicate whether the corresponding configuration (e.g., CSI-RS resource) uses the same spatial domain filter or a different spatial domain filter from other configurations (e.g., other CSI-RS resources within the same CSI-RS resource set), or which reference signal it is quasi-co-located (QCL), and if so, what type of QCL it is (e.g., QCLtype A, B, C, D).

[0040] In the following description of embodiments, the terminal may be referred to as UE 11, and the base station may be referred to as eNB 120 or gNB 120. In this disclosure, to illustrate the IoT NTN for IoT UEs, eNB 120 is used as an example as the node providing access to the network; however, gNB 120 can be applied in the same or similar manner.

[0041] Figure 2A and Figure 2B An example of a non-terrestrial network (NTN) is shown. Figure 2AThe image shows an example of a non-terrestrial network (NTN) utilizing a transparent satellite. Figure 2B The diagram illustrates an example of a non-terrestrial network (NTN) utilizing a regenerative satellite. NTN refers to an access network that provides non-terrestrial access for a UE (e.g., UE 110) via an NTN payload and NTN gateway mounted on an airborne or space-borne NTN vehicle. This access network can be provided by more than one eNB (e.g., eNB 120).

[0042] Reference Figure 2A NTN200 represents the network environment corresponding to the transparent satellite. NTN200, acting as eNB 120, may include NTN payload 221 and NTN gateway 223. NTN payload 221 is a network node mounted on a satellite or high altitude platform station (HAPS) that provides connectivity between the serving link (described later) and the feeder link (described later). NTN gateway 223 is an earth station configured on the Earth's surface that uses the feeder link to provide connectivity to NTN payload 221. NTN gateway 223 is a transport network layer (TNL) node. NTN 200 can provide non-terrestrial access to UE 110. NTN 200 can provide non-terrestrial access to UE 110 through NTN payload 221 and NTN gateway 223. The link between NTN payload 221 and UE 110 can be referred to as a service link. The link between NTN gateway 223 and NTN payload 221 can be referred to as a feeder link. A feeder link can be compared to a wireless link.

[0043] NTN payload 221 can receive radio protocol data from UE 110 via the serving link. NTN payload 221 can transparently transmit the radio protocol data to NTN gateway 223 via the feeder link. Therefore, NTN payload 221 and NTN gateway 223 can be viewed as an eNB 120 from the perspective of UE 110. NTN payload 221 and NTN gateway 223 can communicate with UE 110 via the Uu interface, which is a general radio protocol interface. That is, NTN payload 221 and NTN gateway 223 can perform radio protocol communication with UE 110 like an eNB 120. NTN gateway 223 can communicate with core network entity 235 (mobility management entity (MME) or serving gateway (S-GW)) via the S1 interface.

[0044] According to one embodiment, the NTN payload 221 and the NTN gateway 223 can utilize the features described later. Figure 3A The wireless protocol stack in the control plane. Furthermore, according to one embodiment, the NTN payload 221 and NTN gateway 223 can utilize... Figure 3B The wireless protocol stack in the user plane.

[0045] exist Figure 2A The description includes an NTN payload 221 and an NTN gateway 223 in eNB 120, but the embodiments of this disclosure are not limited thereto. For example, an eNB may include multiple NTN payloads. Furthermore, for example, the NTN payload may be provided by multiple eNBs. That is, Figure 2A The implementation scenario shown is an example and does not limit the embodiments of this disclosure.

[0046] Reference Figure 2BNTN 250 represents the network environment corresponding to the regenerative satellite. NTN 250 may include satellite 260 operating as eNB 120. Satellite 260 represents a space-borne vehicle carrying a regenerative payload communication transmitter configured in low-earth orbit (LEO), medium-earth orbit (MEO), or geostationary earthorbit (GEO). Satellite 260 may be referred to as a regenerative payload or a regenerative satellite. Satellite 260 represents a payload configured to transform and amplify uplink RF signals before transmitting them to the downlink, the transformation of which may refer to digital processing including demodulation, decoding, re-encoding, re-modulation, and / or filtering. NTN 250 may include an NTN gateway 265 as an entity connected to satellite 260 and configured on land. NTN gateway 265 is an earth station configured on the Earth's surface that provides connectivity to satellite 260 using the feeder link. NTN 250 can provide non-terrestrial access to UE 110. NTN 250 can provide non-terrestrial access to UE 110 via satellite 260 and NTN gateway 265.

[0047] Satellite 260 can be configured to reproduce signals received from terminal 110 or an earth station (e.g., NTN gateway 265). A Uu interface can be defined between satellite 260 and terminal 110. A satellite radio interface (SRI) on a feeder link can be defined between satellite 260 and NTN gateway 265. Although in Figure 2B Not shown, but satellite 260 can provide inter-satellite links (ISL). The ISL is a transmission link between satellites, and can be a radio interface (e.g., X2 or XN interface) or optical interface, defined or not defined by 3GPP. Satellite 260 can communicate with core network entity 235 (e.g., MME or S-GW) via NTN gateway 265 and S1 interface. According to one embodiment, satellite 260 can utilize the following... Figure 3A The wireless protocol stack on the control plane. Furthermore, according to one embodiment, satellite 260 can utilize... Figure 3B The wireless protocol stack on the user plane.

[0048] Although Figure 2BThe present disclosure describes a satellite 260 used for operation of the eNB 120, but embodiments thereof are not limited thereto. An eNB 120 according to embodiments of the present disclosure can be implemented by a distributed deployment utilizing a centralized unit (CU) configured to perform functions of upper layers of the access network (e.g., packet data convergence protocol, radio resource control, RRC) and a distributed unit (DU) configured to perform functions of lower layers. The interface between the CU and the DU may be referred to as an F1 interface. A CU may connect to more than one DU, thereby handling functions at a higher layer than the DU. For example, a CU may handle the functions of the RRC (radio resource control) and PDCP (packet data convergence protocol) layers, while the DU and radio units (RUs) handle lower-layer functions. The DU can be responsible for radio link control (RLC), media access control (MAC), and physical (PHY) layer functions. In such a distributed deployment, Satellite 260 can be used as a CU or DU constituting the eNB-120.

[0049] Figure 3A An example of a control plane (C-plane) is shown. At least part of the following description of eNB 120 can be understood as a description of satellite 260.

[0050] Reference Figure 3A In the C-plane, UE 110 and AMF 235 can execute non-access stratum (NAS) signaling. In the C-plane, UE 110 and eNB 120 can perform communications corresponding to the specified protocols at the RRC, PDCP, RLC, MAC, and PHY layers.

[0051] In NTN access, the main functions of the RRC layer may include at least some of the following functions.

[0052] - Access Stratum (AS) and NAS related system information broadcasting - Paging - This includes setting, maintaining, and disabling the RRC connection between the UE and the access network, and more specifically, control over RLC, MAC, and PHY: - Adding, modifying, and deactivating carrier aggregation - Adding, modifying, and disabling dual connectivity between NR or E-UTRA and NR.

[0053] - Includes security features such as key management; - Configuration, setup, maintenance, management, and deactivation of Signaling Radio Bearer (SRB) and Data Radio Bearer (DRB) - Includes the following mobile features: - Switching and context passing; - UE cell selection and reselection, and cell selection and reselection control; - Mobility between RATs.

[0054] - Quality of service (QoS) management functions; - UE measurement reports and report control; - Radio link failure detection and recovery - Message transmission from / to the UE to / from the NAS to the NAS.

[0055] In NTN access, the main functions of the PDCP layer may include at least some of the following functions.

[0056] - Header compression and decompression function (ROHC only) - User data transfer function - In-sequence delivery of upper layer PDUs - Out-of-sequence delivery of upper layer PDUs - Duplicate detection of lower layer SDUs - Retransmission of PDCP SDUs - Encoding and decoding functions (Ciphering and deciphering) - Timer-based SDU discard in uplink. In NTN access, the main functions of the RLC layer may include at least some of the following functions.

[0057] - Data transfer function (Transfer of upper layer PDUs) - In-sequence delivery of upper layer PDUs - Out-of-sequence delivery of upper layer PDUs - ARQ function (Error Correction through ARQ) - Concatenation, segmentation, and reassembly of RLC SDUs - Re-segmentation of RLC data PDUs - Reordering of RLC data PDUs - Duplicate detection function - Protocol error detection function - RLC SDU discard function - RLC re-establishment function In NTN access, the MAC layer can be connected to multiple RLC layer devices configured in a terminal, and the main functions of the MAC layer can include at least some of the following functions.

[0058] - Mapping between logical channels and transport channels - Multiplexing and demultiplexing of MAC SDUs - Scheduling information reporting function - Error correction through HARQ functionality - Priority handling between logical channels of a UE - Priority handling between UEs by means of dynamic scheduling - MBMS service identification function - Transport format selection function - Padding function In NTN access, entities in the physical layer (e.g., terminal 110, eNB 120) can perform actions such as channel coding and modulation of upper-layer data to create OFDM symbols and transmit them through the wireless channel, or demodulate and decode OFDM symbols received through the wireless channel and transmit them to the upper layer.

[0059] Figure 3B An example of a user plane (U-plane) is shown. At least part of the following description of eNB 120 can be understood as a description of satellite 260.

[0060] Reference Figure 3BIn the U-plane, UE 110 and eNB 120 can perform communication corresponding to the specified protocols at the PDCP layer, RLC layer, MAC layer, and PHY layer, respectively. For details on the PDCP layer, RLC layer, MAC layer, and PHY layer, please refer to the documentation for... Figure 3A Explanation.

[0061] Figure 4 Examples of time-frequency domain resource structures supported by wireless communication systems applicable to embodiments presented in this specification are shown. Although in Figure 4 The resource structure of an LTE network for IoT NTN is described in the examples, but the embodiments of this disclosure are not limited thereto. The signaling and associated actions according to the embodiments of this disclosure can also be applied to NR systems in the same or similar manner.

[0062] Reference Figure 4 The horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest unit of transmission in the time domain is an OFDM symbol, N. symb 402 OFDM symbols converge to form a slot 406 (e.g., 7 slots in an LTE system). See reference. Figure 4 In a wireless communication system to which this invention applies, a radio frame 414 can be defined as consisting of 10 subframes of equal length, each having a length of 1 ms. Furthermore, a radio frame 414 can be divided into half-frames of 5 ms each, with each half-frame comprising 5 subframes. Although in Figure 4 Time slot 406 consists of 7 OFDM symbols, but the length of the time slot can be varied according to the subcarrier spacing. The radio resource supported in the wireless communication system applicable to the invention presented in this specification consists of multiple symbols as time resources and multiple subcarriers as frequency resources, each of which can be represented by a two-dimensional resource grid. Figure 4 In this context, a rectangle representing the smallest physical resource consisting of a subcarrier and a symbol within the resource grid is called a Resource Element (RE).

[0063] In wireless communication systems to which the inventions proposed herein are applicable, the smallest unit of transmission in the frequency domain is a subcarrier, and the carrier bandwidth constituting the resource grid can be N. BW The resource is composed of N subcarriers 404. The basic unit of resources in the time-frequency domain is a resource element (hereinafter referred to as "RE"), which can be represented by an OFDM symbol index and a subcarrier index. A resource block 408 can include multiple resource elements 412. In a wireless communication system to which the invention proposed herein applies, a resource block 408 (or a physical resource block (hereinafter referred to as "PRB")) can be composed of N subcarriers 404 in the time domain. symb Seven (e.g., 7) consecutive OFDM symbols and N in the frequency domain SC RB The data rate is defined as 410 consecutive subcarriers (e.g., 12). The data rate can increase proportionally to the number of RBs scheduled to the terminal. In the case of a frequency division duplex (FDD) system that distinguishes between downlink and uplink frequencies and operates accordingly, the downlink and uplink transmission bandwidths may differ from each other. Channel bandwidth represents the radio frequency (RF) bandwidth corresponding to the system's transmission bandwidth. For example, the channel bandwidth can be one of 1.4 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).

[0064] E-UTRAN can support radio access via non-terrestrial networks (NTNs) not only for ordinary UEs, but also for BL (bandwidth-limited) UEs, CE (coverage enhancement) UEs, and NB-IoT UEs. Non-terrestrial network support can include platforms providing radio access via geostationary orbit (GSO), non-geostationary orbit (NGSO) (including low Earth orbit (LEO) and medium Earth orbit (MEO)), or high-altitude platform stations (HAPS). In the transparent payload mode, the NTN gateway and the NTN payload (i.e., the satellite) jointly act as the eNB; in the regenerative payload mode, the NTN payload (i.e., the satellite) can act as the eNB.

[0065] Transparent NTN payloads transparently forward radio protocols received by the UE (via the serving link) to the NTN gateway (via the feeder link) and vice versa. Regenerated payloads can terminate connections with the Uu interface (via the serving link), S1, and X2 interfaces. An NTN gateway can support multiple transparent or regenerated NTN payloads. Transparent or regenerated NTN payloads can be served by multiple eNBs. Regenerated NTN payloads can terminate connections with one or more inter-satellite links pointing to other regenerated payloads. As a non-limiting example, transparent NTN payloads can change the carrier frequency before forwarding via the serving link and vice versa (in the feeder link, respectively). In non-terrestrial networks, the tracking area can correspond to a fixed geographical area. In non-terrestrial networks, the same value can be used in the AS (Access Stratum) and NAS (Non-Access Stratum) when the satellite ID refers to the same satellite.

[0066] Three types of service links can be supported in non-terrestrial networks: Earth-fixed: Provided by a beam that continuously covers the same geographical area (e.g., GSO satellite).

[0067] Quasi-Earth-fixed: Provides beam coverage by covering one geographic area for a limited time and another geographic area for other times (e.g., the case of NGSO satellites generating controllable beams).

[0068] Earth-moving: Provided by a beam that moves across the Earth's surface as if gliding over a coverage area (e.g., the case of NGSO satellites generating fixed or uncontrollable beams).

[0069] eNBs using NGSO satellites can provide quasi-ground fixed cell coverage or ground mobile cell coverage, while eNBs using GSO satellites can provide ground fixed cell coverage or quasi-ground fixed cell coverage.

[0070] Store-and-forward (S&F) mode can be used to provide communication services to the UE when the serving satellite and terrestrial network have discontinuous connections, and when this connection is unavailable during satellite-UE interaction. The eNB can indicate whether the cell is operating in store-and-forward mode. Store-and-forward mode refers to the operating mode that provides communication services to the UE when the serving satellite and NTN gateway have discontinuous connections, and when the connection to the NTN gateway is unavailable during satellite-UE interaction.

[0071] Figure 5 Example 500 illustrates the store-and-forward (S&F) mode in a non-terrestrial network (NTN) for the Internet of Everything (IoT).

[0072] Reference Figure 5 UE 510 can communicate with satellite 520. UE 510 can be referenced as... Figure 1Terminal 110. Satellite 520 can be referenced to base station 120 or a network entity performing at least a portion of the functions of base station 120. According to one embodiment, satellite 520 can be an eNB providing IoT NTN. Satellite 520 can provide E-UTRAN for IoT devices (e.g., UE 510). UE 510 can access satellite 520 in E-UTRAN. The connection between satellite 520 and UE 510 can be referenced to a service link. Satellite 520 can move along a designated orbit. As satellite 520 moves, satellite 520 can connect to a network entity configured on land (hereinafter, the land segment) (e.g., NTN gateway 530). The connection between satellite 520 and NTN gateway 530 can be referenced to a feeder link. NTN gateway 530 can connect to core network 550 via transport network 540. As satellite 520 repeatedly moves along the designated orbit, the service link may become available or unavailable. As satellite 520 moves repeatedly along the specified orbit, the feeder link may become available or unavailable.

[0073] Satellite 520 can support store-and-forward (S&F) mode. S&F mode refers to the operating mode of a system capable of satellite-access. Through S&F mode, delay-tolerant communication services can be provided. When satellite connectivity is intermittently or temporarily unavailable (e.g., providing service to UE 510 located in a coverage area where the feeder link associated with the terrestrial portion (e.g., NTN gateway 530) is not simultaneously activated), a service level of data storage and forwarding can be provided. According to one embodiment, satellite 520 can be used to provide delay-tolerant IoT services via NGSO (non-geostationary satellite orbit) (e.g., LEO (low earth orbit)). According to one embodiment, satellite 520 can provide satellite access to UE 510 that is not equipped with a global navigation satellite system (GNSS) receiver or has limited access to GNSS services. As an unrestricted example, satellite 520 can perform UE-satellite-UE communication with UE 510. For example, to avoid longer latency and limited data rates and reduce resource consumption, UE 510 can also communicate with satellite 520 without communicating with the terrestrial portion (e.g., NTN gateway 530). S&F mode can be used for latency-tolerant and / or interruption-tolerant services. For example, within the 3GPP context, short message service (SMS) can be used for S&F mode, and an end-to-end connection between the endpoints (e.g., UE 510 and the application server) may not be required. Only a connection between the endpoint (e.g., UE 510) and an intermediate node (e.g., short message service center (SMSC)) may be required.

[0074] In S&F mode, the service link between UE 510 and satellite 520 may repeatedly be in an available and unavailable state. An available service link between UE 510 and satellite 520 means that the location of satellite 520 falls within the range of its orbit that can provide service to the area where UE 510 is located (e.g., the footprint) (hereinafter, the available orbit range). An unavailable service link between UE 510 and satellite 520 means that the location of satellite 520 falls within the range of its orbit that makes it difficult to provide service to the area where UE 510 is located (e.g., the footprint) (hereinafter, the unavailable orbit range). In S&F mode, the feeder link between satellite 520 and the terrestrial portion (e.g., NTN gateway 530) may repeatedly be in an available and unavailable state. The service link between satellite 520 and the land segment (e.g., NTN gateway 530) being available means that the position of satellite 520 falls within the range of its orbit that can provide service to the area (e.g., footprint) where the land segment (e.g., NTN gateway 530) is located (hereinafter, the available feeder orbit range). The service link between satellite 520 and the land segment (e.g., NTN gateway 530) being unavailable means that the position of satellite 520 falls within the range of its orbit that makes it difficult to provide service to the area (e.g., footprint) where the land segment (e.g., NTN gateway 530) is located (hereinafter, the unavailable feeder orbit range). For UE510, the availability of the service link and the availability of the feeder link may not always occur simultaneously. For example, even if the status of the service link changes from available to unavailable, it does not necessarily mean that the status of the feeder link changes.

[0075] According to one embodiment, UE 510 can transmit signals. These signals may be mobile-originating (MO) data. For example, in action 591, when the serving link is available, UE 510 can transmit uplink data (e.g., PUSCH) to satellite 520. Satellite 520 can receive the uplink data from UE 510. Since the feeder link is unavailable, satellite 520 can store the uplink data. Subsequently, satellite 520 can move. With this movement, the state of the feeder link may change from unavailable to available. In action 592, satellite 520 can transmit the uplink data via a network entity configured on land (e.g., NTN gateway 530). The uplink data can be transmitted to the data network via core network 550. Hereinafter, in S&F mode, the service of transmitting messages sent by UE 510 via satellite 520 can be referred to as MO service.

[0076] According to one embodiment, satellite 520 can transmit signals to UE 510. These signals may be mobile terminated (MT) data. For example, in action 593, while the feeder link is available, satellite 520 can receive data from external devices (e.g., servers, other UEs) via the data network and core network 550 (e.g., UPF). Satellite 520 can move. As satellite 520 moves, the state of the feeder link may change from available to unavailable. As satellite 520 moves, the state of the service link between satellite 520 and UE 510 may change from unavailable to available. In action 594, when the service link is available, satellite 520 can transmit downlink data (e.g., PDSCH) to UE 510. Hereinafter, the service of messages transmitted in UE 510 via satellite 520 in S&F mode can be referred to as MT service.

[0077] 1. Indication signaling related to S&F mode. For S&F mode, UE 510 can receive indications from system information broadcast from the serving satellite (e.g., satellite 520) indicating whether the serving satellite is currently operating in S&F mode. In satellite systems using S&F mode, the feeder link status can affect UE 510's operation within a range of RRC states. From UE 510's perspective, there are three possible scenarios.

[0078] 1) Normal operation: Both the service link and the feeder link are available simultaneously. 2) S&F Action: Only service links are available 3) Combined Actions: Changes in the state of the feeder link at specific points in time during the coverage path. For example, an earth-moving cell (where the reception range on the ground surface changes as the satellite moves). In order to effectively manage scenarios, UE 510 needs to be able to identify the current action mode through the indications provided in the system information. Therefore, UE 510 is required to know the following information.

[0079] -Does the service satellite support S&F connectivity? -Feeder status of the service satellite. - Remaining duration of the current feeder link state By providing the above information, UE 510 can perform appropriate actions under various conditions. If the serving satellite supports S&F connectivity, the actions of UE 510 can be modified based on the status of the satellite's feeder link.

[0080] When the feeder link is available, the remaining duration corresponds to the validity period of the normal operation mode (hereinafter, normal mode). When the feeder link is unavailable, the remaining duration corresponds to the validity period of the S&F operation mode (i.e., S&F mode). Furthermore, when the serving link is unavailable, the duration of the serving link corresponds to the validity period of the S&F operation mode (i.e., S&F mode). Similarly, when the serving link is unavailable, the duration of the serving link corresponds to the start time of the S&F operation mode (i.e., S&F mode). Although UE 510 can know the status of the serving link, it cannot directly know the status of the feeder link; therefore, it is required to know the status of the feeder link. Furthermore, UE 510 is required to know the duration of the serving link. In the following embodiments of this disclosure, in order for UE 510 to determine how to act in what scenarios for a serving satellite (e.g., satellite 520), technologies related to signaling provided on the network side will be described.

[0081] According to embodiments of this disclosure, a network (e.g., an eNB) can indicate store-and-forward (S&F) mode to a terminal (e.g., a UE) via an SIB1 message. For example, the "sf-OperationMode" IE can be included in the SIB1 message. This IE can indicate that the cell is operating in store-and-forward mode. When this field is present, a UE supporting store-and-forward operations can ignore cellBarred-NTN and cellBarred. The IE can point to either a "barred" or "notBarred" value. The value "barred" indicates that the cell has been barred for NTN connections via store-and-forward operations as defined in TS 36.304. The value "notBarred" indicates that the cell allows access for UEs supporting store-and-forward operations. If this field is not present, the SIB1 message can indicate that the NTN cell is operating in general mode, i.e., non-store-and-forward mode.

[0082] According to embodiments of this disclosure, a network (e.g., an eNB) can indicate time information related to the store-and-forward mode to a terminal (e.g., a UE) via SIB31. SIB31 may contain satellite assistance information about the serving cell. As said satellite assistance information, ephemeris information, satellite ID, and information about the reference location may be included in SIB31. According to one embodiment, the SIB31 message may contain switching time information (e.g., t-ModeSwitching IE). If SIB31 contains... sf-OperationMode If the NTN cell switches from store-and-forward operation mode to normal mode, then this field indicates the time information. Otherwise, this field indicates the time information of the NTN cell switching from normal mode to store-and-forward mode.

[0083] Figure 6 Signaling indicating information related to the effective time of the S&F mode. Satellite 520 can be configured to perform the functions of an eNB. As an example, the eNB can be configured on the payload of satellite 520, with the entity of the core network (e.g., core network 550) configured on land. As an example, the eNB and a portion of the core network entity (or, a portion of a specific entity (e.g., a mobile management entity, MME)) can be configured on the payload of satellite 520, with another portion of the core network entity configured on land.

[0084] Reference Figure 6 In action 601, satellite 520 can transmit information related to the validity period of the S&F mode to UE 510. The validity period of the S&F mode can refer to the duration during which the S&F mode of satellite 520 is active. For example, the validity period of the S&F mode can represent the remaining period until the feeder link of satellite 520 is unavailable and the corresponding feeder link changes from unavailable to available. In such cases, the validity period of the S&F mode can be satellite-specific or cell-specific. Since the feeder link is the connection between satellite 520 and the land station, the state of the feeder link between satellite 520 and the land station can be determined based on the orbit of satellite 520. Therefore, satellite 520 can know the expected time when the feeder link will be restored. The validity period of the S&F mode can be indicated independently of the state of the serving link.

[0085] According to one embodiment, the effective time of the S&F mode can represent the time point at which the feeder link connection is restarted. This time point can be indicated as an absolute time. In 3GPP, a "t-service" information element (IE) is defined to represent the service time of a cell provided by satellite 520. The "t-service" IE represents time information related to the time at which the service provided by the NTN system in the currently responsible area is to be interrupted. This IE can be applied to service link handovers for the NTN quasi-Earth fixed system and to all feeder link handovers for both the NTN quasi-Earth fixed system and the NTN Earth moving system. The IE represents time in multiples of 10 ms after 00:00:00 on January 1, 1900 (midnight between Sunday, December 31, 1899 and Monday, January 1, 1900). The exact stop time is the time represented by the value minus 1 from the value of this field and the time represented by the value of this field. The reference point associated with the IE is the uplink time synchronization reference point of the cell. This allows the validity period of the S&F mode to be indicated. For example, the validity period of the S&F mode can be indicated as an absolute time point, similar to the t-service IE. As another example, the validity period of the S&F mode can be indicated using a hyperframe number (HFN), system frame number (SFN), radio frame (RF), subframe (SF), and / or symbol index. As an example, the validity period of the S&F mode can be indicated as follows.

[0086] Table 1

[0087] “t-feederStart-r19”IE can indicate the start time of the feeder link of the cell (i.e., NTN cell) provided by satellite 520.

[0088] In order to indicate not only the feeder link associated with the serving satellite, but also the effective time of the S&F mode associated with neighboring satellites, the start time point of the feeder link associated with neighboring satellites can be indicated.

[0089] Table 2

[0090] “t-feederStartNeigh-r19”IE can indicate the time point at which the feeder link of the satellite adjacent to satellite 520 begins.

[0091] To represent absolute time information, the UTC format can be used. Refer to the table below for the UTC format.

[0092] Table 3

[0093] According to another embodiment, the validity period of the S&F mode can be indicated as a relative time. For example, the relative time can refer to the difference between the time when the service terminates (e.g., "t-service" IE) of the NTN-based cell and the time when the feeder link connection is restarted. In other words, the validity period of the S&F mode can be indicated as a relative time (e.g., offset). As an example, the validity period of the S&F mode can be indicated as a relative value to the absolute value indicated by t-service.

[0094] Satellite 520 can transmit information related to the validity period of the S&F mode. According to one embodiment, satellite 520 can broadcast information related to the validity period of the S&F mode via system information. For example, the system information could be SIB 31. For example, the system information could be SIB 32. As another example, satellite 520 can broadcast information related to the validity period of the S&F mode of neighboring satellites via SIB 33. According to another embodiment, satellite 520 can transmit information related to the validity period of the S&F mode via RRC messages (e.g., RRC reconfiguration messages). In the event that a terrestrial station connected to satellite 520 via a feeder link is replaced or satellite 520 changes from normal mode to S&F mode, satellite 520 can change the RRC configuration of the corresponding cell while maintaining the RRC connection status.

[0095] Satellite 520 may transmit information related to the validity period of the S&F mode along with other information. According to one embodiment, satellite 520 may transmit information related to the validity period of the S&F mode along with its operating mode via a message (e.g., system information (SI) or RRC message). The operating mode may include an indicator indicating whether it is in normal mode or S&F mode. For example, if the operating mode indicates S&F mode, information related to the validity period of the S&F mode may be included in the message. According to one embodiment, satellite 520 may transmit information related to the current feeder link status along with a message (e.g., SI (system information) message or RRC message). The information related to the feeder link status may include an indicator indicating whether the current feeder link status is available or unavailable. For example, if the information indicates that the feeder link status is unavailable, information related to the validity period of the S&F mode may be included in the message.

[0096] 2. S&F mode and RRC states When the satellite switches to S&F mode, it's necessary to define how UE 510 in RRC-connected state should operate. This is because the network cannot acquire new downlink data related to the UE during S&F mode. On the other hand, in the case of uplink data, UE 510 can continue data transmission using the network as long as it allows. Since satellite 520 acts as a RAN node, it can release the DRB, which requires a strict standby time, when the feeder link is disconnected. When data transmission is complete, satellite 520 can release the UE's RRC connection for power saving purposes. In the case of UE 510 in RRC-connected state, the network switches to S&F mode, which may prevent UE 510 from automatically transitioning to idle state. When satellite 520 is switched to S&F mode via network configuration, only the DRB with the allowed standby time can be maintained.

[0097] Figure 7 This example illustrates the RRC (radio resource control) connection status of an IoT UE (user equipment).

[0098] Reference Figure 7The RRC layer is responsible for signal management between UE 510 and satellite 520. In addition to setting, maintaining, and disabling wireless connections, the RRC layer also handles mobility and security operations. The RRC layer states (hereinafter, RRC states) can include RRC connected state 710 corresponding to the connected mode and RRC idle state 720 corresponding to the standby mode. Each state performs different purposes during communication, and through state transitions, the UE can efficiently communicate with the network while managing battery consumption. UE 510 can perform transitions between RRC connected state 710 and RRC idle state 720 based on network activity. These transitions can be triggered in the network by factors such as user data requests, signal activity, or power-saving requirements. For example, the transition from RRC idle state 720 to RRC connected state 710 occurs when UE 510 needs to send or receive data. UE 510 can transition to the connected state by sending an RRC connection request. For example, the transition from RRC connected state 710 to RRC idle state 720 occurs when UE 510 is no longer involved in active communications. When the network side (e.g., satellite 520) releases radio resources, UE 510 can return to standby mode to conserve battery power.

[0099] In RRC Idle State 720, UE 510 will not actively send or receive user data and may not be allocated dedicated resources in the network. However, UE 510 can still monitor network paging messages and system information. UE 510 can use minimal power to conserve battery life. In RRC Idle State 720, UE 510 can perform Cell Reselection, which continuously monitors the signal strength of neighboring cells and switches to a better cell as needed. Furthermore, in RRC Idle State 720, UE 510 can perform Paging Reception, which receives paging messages from the network (e.g., satellite 520) and acknowledges incoming calls, SMS, or mobile terminal data session information. UE 510 can perform Discontinuous Reception (DRX), which involves periodically waking up to acknowledge paging messages and remaining inactive for the rest of the time to conserve power. UE 510 can perform a tracking area update (TAU) step, in which it updates its position to the network (e.g., satellite 520) when moving between different tracking areas, so that the network can track UE 510 for future communication.

[0100] Figure 8AAn example of terminating an RRC connection in S&F mode is shown. Satellite 520 can be configured to perform the functions of an eNB. As an example, the eNB can be configured on the payload of satellite 520, with the entity of the core network (e.g., core network 550) configured on land. As an example, the eNB and a portion of the core network entity (or, a portion of a specific entity (e.g., MME (mobile management entity))) can be configured on the payload of satellite 520, with another portion of the core network entity configured on land.

[0101] Reference Figure 8A In action 810, UE 510 and satellite 520 can communicate in RRC connection state (e.g., RRC connection state 710).

[0102] In action 801, satellite 520 can operate in S&F mode. When satellite 520 enters S&F mode, it can determine whether to terminate the RRC connection with UE 510. In S&F mode, satellite 520 will not be able to acquire new downlink data. However, satellite 520 can acquire uplink data from UE 510. Satellite 520 can determine whether to terminate the RRC connection based on the communication service connected to UE 510. According to one embodiment, satellite 520 can determine whether to terminate the RRC connection based on the status of the feeder link. As an example, the status of the feeder link may include the expected recovery time of the feeder link, the channel capacity of the feeder link, the time the feeder link was disconnected, and / or the unavailability time of the feeder link. According to one embodiment, satellite 520 can determine whether to terminate the RRC connection based on the status of the serving link. As an example, if the channel quality (e.g., RSRP, CQI, SINR) measured in the serving link shows a channel quality below a critical value, satellite 520 can determine to terminate the RRC connection. According to one embodiment, satellite 520 can determine whether to terminate the RRC connection based on the DRB. For example, if the packet delay budget of the DRB's QCI is below a critical value, satellite 520 can determine to terminate the connection. RRC Connection. According to one embodiment, satellite 520 can determine whether to terminate the RRC connection based on QoS flows. For example, if the allowed latency time is less than a threshold based on the 5QI associated with the QoS flow, satellite 520 can determine to terminate the RRC connection. According to another embodiment, satellite 520 can determine whether to terminate the RRC connection based on network slices. For example, if the slice service type (SST) and / or slice differentiator (SD) of the network slice indicates a latency-sensitive service (e.g., SST indicates URLLC), satellite 520 can determine to terminate the RRC connection. Hereinafter, satellite 520 can determine to terminate the RRC connection with UE 510.

[0103] In action 803, satellite 520 may transmit control signals to UE 510. Satellite 520 may transmit control signals to terminate the RRC connection. According to one embodiment, the control signal may be an RRC message for terminating the RRC connection. According to another embodiment, the RRC message may contain configuration information for constituting the S&F mode.

[0104] Table 4

[0105] According to one embodiment, the RRC message used to terminate the RRC connection is a reason value for termination, which may include "StoreandForward".

[0106] Table 5

[0107] As an unrestricted example, with Figure 8A Unlike the example shown, satellite 520 can also use a message other than the RRC message used to disconnect the RRC connection to transmit configuration information for setting up S&F mode to UE 510.

[0108] In action 805, UE 510 can terminate the RRC connection. UE 510 can respond to the control signal to perform the steps for terminating the RRC connection. As the RRC connection is terminated, the connection state of UE 510 changes from an RRC connected state to an RRC idle state.

[0109] In action 820, and in action 810, UE 510 can be in an RRC idle state (e.g., RRC idle state 720). UE 510 can be configured to perform... Figure 7 The actions during RRC idle state 710 are illustrated in the diagram. For example, UE 510 can monitor paging messages and / or system information. For example, UE 510 can perform cell reselection.

[0110] Although Figure 8A Examples of terminating an RRC connection are described, but embodiments of this disclosure are not limited thereto. For example, in addition to terminating an RRC connection, the low-power mode of the UE 510 can also be triggered via MAC CE or DCI. As another example, an inactivity timer for S&F mode can also be configured. The inactivity timer can cause the UE 510 to terminate its RRC connection if no data is transmitted during a predetermined period.

[0111] Figure 8B This illustrates an example of requesting the termination of an RRC connection in S&F mode. Satellite 520 can be configured to perform the functions of an eNB. As an example, the eNB can be configured on the payload of satellite 520, with the entity of the core network (e.g., core network 550) configured on land. As an example, the eNB and a portion of the core network entity (or, a portion of a specific entity (e.g., MME (mobile management entity))) can be configured on the payload of satellite 520, with another portion of the core network entity configured on land.

[0112] Reference Figure 8B In action 810, UE 510 and satellite 520 can communicate in RRC connection state (e.g., RRC connection state 710).

[0113] In action 851, satellite 520 can operate in S&F mode. In S&F mode, satellite 520 will not be able to acquire new downlink data. However, satellite 520 can acquire uplink data from UE 510. Whether to terminate the RRC connection can be determined based on whether there is uplink data from UE 510. If there is no data transmission or reception during a predetermined period, satellite 520 can terminate the RRC connection through preset parameters (e.g., an inactive timer). For example, if there is no traffic with UE 510, the eNB of satellite 520 can send a UE context termination request to the MME and receive a UE context termination complete message from the MME. Subsequently, satellite 520 can send an RRC connection termination message. However, such steps not only require waiting for the inactive timer to terminate, but also take more time when terminating the RRC connection. Therefore, satellite 520 can monitor the status of UE 510 and determine whether to terminate the RRC connection based on UE 510's request.

[0114] In action 853, satellite 520 may transmit a message to UE 510 to notify satellite 520 of the action in S&F mode. According to one embodiment, the message may include messages associated with action conditions. For example, the action conditions may represent triggering conditions for requesting termination of the RRC connection of UE 510. For example, the message may include a list of data services used to maintain the RRC connection even in S&F mode without termination. As an example, the list may include a list of Data Radio Bearers (DRBs), a list of Quality of Service Flows (QoS Flows), a list of Single Network Slice Selection Assistance Information (S-NSSAI), and / or a list of resource areas (e.g., BWPs, PRBs, subbands). For example, the message may include threshold values ​​for metrics (e.g., RSRP, SINR). When channel quality is measured above the threshold value of the metric, UE 510 may perform communication without requesting termination of the RRC connection. When the channel quality measured is below a threshold value, UE 510 may request to terminate the RRC connection. For example, the message may contain a data traffic threshold. If the amount of data to be transmitted (e.g., the amount of data held in the buffer, transport block size (TBS)) is below the data traffic threshold, UE 510 may perform communication without requesting to terminate the RRC connection. If the amount of data to be transmitted is above the data traffic threshold, UE 510 may request to terminate the RRC connection.

[0115] In action 855, UE 510 can confirm the action conditions. UE 510 can determine whether the action conditions are met based on the message received in action 853. When the action conditions are met, UE 510 can execute action 857 based on the message received in action 853. For example, UE 510 can execute action 857 if the channel quality is measured to be below a threshold value. For example, UE 510 can execute action 857 if the amount of data to be transmitted is above the threshold value of the data traffic. As a non-limiting example, UE 510 can confirm that there is no more data after completing the uplink transmission. UE 510 can determine that the action conditions are met. According to one embodiment, after completing the uplink transmission, the RRC connection can be terminated even without a request from UE 510 after a period of inactivity timer has elapsed. Therefore, a request from UE 510 becomes meaningful when requested within a shorter time than the inactivity timer. UE 510 can determine whether the action condition is met based on the time of the inactive timer (e.g., by comparing the time associated with the round-trip time (RTT) between UE 510 and UE 510 with the time of the inactive timer). Although in Figure 8B As not shown, UE 510 may perform uplink data communication when the aforementioned action conditions are not met. After repeatedly determining whether the action conditions are met, action 875 may be executed when the action conditions are met.

[0116] In action 857, UE 510 may transmit a request signal based on the determination that action conditions are met. To quickly request the termination of the RRC connection, UE 510 may transmit the request signal. For example, the request signal may include an indicator of directly requesting the termination of the RRC connection. For example, the request signal may include an indicator indicating that the conditions set in the message of action 853 are met. Satellite 520 may determine whether to transmit an RRC connection termination message based on the indicator. For example, the request signal may transmit information related to the measured channel quality. Satellite 520 may determine whether to transmit an RRC connection termination message based on the information. For example, the request signal may include the amount of data held in the uplink buffer of UE 510. Satellite 520 may determine whether to transmit an RRC connection termination message based on the amount.

[0117] The request signal according to various embodiments of this disclosure can be executed through one of various steps. According to one embodiment, the request signal can be executed via an RRC message. In S&F mode, an additional RRC message can be defined for requesting the termination of the RRC connection. According to one embodiment, the request signal can execute a random access procedure. The request to terminate the RRC connection can be indicated by a random access preamble or message 3. According to one embodiment, the request signal can be executed via a predefined timing sequence. UE 510 can provide the request to terminate the RRC connection to satellite 520 by transmitting a predefined timing sequence (e.g., the m value, cyclic shift (cs) value, and pattern) on the PUCCH. According to one embodiment, the request signal can be executed via a MAC CE (control element). For example, the MAC CE can include a BSR (buffer status reporting) MAC CE (control element). The BSR can be used not only to request the amount of uplink data but also to request the termination of the RRC connection. With the amount of uplink data below a threshold (e.g., 0 or a specified value) included in the BSR MAC CE, satellite 520 can indirectly identify a request to terminate the RRC connection for the BSR MAC CE.

[0118] Satellite 520 can determine whether to terminate the RRC connection based on the request signal. Upon determining to terminate the RRC connection, satellite 520 can transmit an RRC connection termination message to UE 510.

[0119] In action 820, and in action 810, UE 510 can be in an RRC idle state (e.g., RRC idle state 720). UE 510 can be configured to perform... Figure 7 The actions during RRC idle state 710 are illustrated in the diagram. For example, UE 510 can monitor paging messages and / or system information. For example, UE 510 can perform cell reselection.

[0120] Although Figure 8AExamples of terminating an RRC connection are described, but embodiments of this disclosure are not limited thereto. For example, in addition to requesting termination of the RRC connection, the low-power mode of the UE 510 can also be triggered via MAC CE or DCI. As another example, an inactivity timer for S&F mode can also be configured. The inactivity timer for S&F mode can cause the termination of the RRC connection of the UE 510 if there is no data transmission during a predetermined period. The length of the inactivity timer for S&F mode can be set shorter than the length of the inactivity timer set between a normal operation available on both the serving link and the feeder link and / or between a general terrestrial base station and the terminal.

[0121] Figure 9 Examples of the constituent elements of a UE (e.g., UE 510) are shown.

[0122] Reference Figure 9 UE 510 may include a transceiver 901, a processor 903, and a memory 905. The transceiver 901 performs functions for transmitting and receiving signals via a wireless channel. For example, the transceiver 901 uplinks baseband signals to RF band signals and transmits them through an antenna, and downlinks RF band signals received through the antenna back to baseband signals. For example, the transceiver 901 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC (digital-to-analog converter), an ADC (analog-to-digital converter), etc.

[0123] Transceiver 901 may include multiple transmit / receive paths. Further, transceiver 901 may include an antenna section. Transceiver 901 may include at least one antenna array composed of multiple antenna elements. From a hardware perspective, transceiver 901 may be composed of digital circuitry and analog circuitry (e.g., radio frequency integrated circuit (RFIC)). Here, the digital and analog circuitry may be implemented in a single package. Furthermore, transceiver 901 may include multiple RF chains. Transceiver 901 may perform beamforming. To impart directionality to the signals to be transmitted and received corresponding to the settings of processor 903, transceiver 901 may apply beamforming weights to the signals. According to one embodiment, transceiver 901 may include an RF (radio frequency) block (or RF section). According to one embodiment, transceiver 901 may support satellite communication. UE 510 can transmit signals to or receive signals from a satellite (e.g., satellite 520) via transceiver 901.

[0124] Transceiver 901 can transmit and receive signals on a radio access network. For example, transceiver 901 can receive downlink signals. Downlink signals may include synchronization signals (SS), reference signals (RS) (e.g., cell-specific reference signal (CRS), demodulation reference signal (DM(demodulation)-RS)), system information (e.g., MIB, SIB, remaining system information (RMSI), other system information (OSI)), configuration messages, control information, or downlink data, etc. Furthermore, transceiver 901 can also transmit uplink signals, for example. The uplink signals may include random access association signals (e.g., random access preamble (RAP) (or message 1, Msg1), message 3, Msg3), reference signals (e.g., sounding reference signal (SRS), DM-RS), uplink control information (UCI) (e.g., channel state information (CSI), hybrid automatic repeat request (HARQ), scheduling request (SR)), or power headroom report (PHR), etc. Although in Figure 9 Only transceiver 901 is shown in the figure. According to other implementation examples, UE 510 may include more than two RF transceivers.

[0125] Processor 903 controls the overall operation of UE 510. Processor 903 can be referred to as a control unit. For example, processor 903 sends and receives signals via transceiver 901. Furthermore, processor 903 records and retrieves data from memory 905. In addition, processor 903 can execute the functions of the protocol stack required by the communication specification. Although in Figure 9Only processor 903 is shown in this embodiment; however, according to other implementations, UE 510 may include two or more processors. Processor 903 is a set of instructions or code stored in memory 905. It may be instructions / code that are at least temporarily resident in processor 903 or a storage space storing instructions / code, or it may be part of the circuitry of processor 903. Furthermore, processor 903 may include various modules for performing communication. Processor 903 can control UE 510 to perform the actions of the embodiments.

[0126] Memory 905 stores data such as basic programs, application programs, and setting information for the operation of UE 510. Memory 905 may be referred to as a storage unit. Memory 905 may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Furthermore, memory 905 provides the stored data according to requests from processor 903. According to one embodiment, memory 905 may include memory for conditions, instructions, or setting values ​​associated with satellite communication transmission methods.

[0127] Figure 10 Examples of the constituent elements of a satellite (e.g., satellite 520) are shown.

[0128] Reference Figure 10 Satellite 520 may include at least one transceiver 1001, at least one processor 1003, and at least one memory 1005. Hereinafter, the constituent elements are described in the singular, but implementations of multiple constituent elements or sub-constituent elements are not excluded.

[0129] Transceiver 1001 performs functions for transmitting and receiving signals via a wireless channel. For example, transceiver 1001 performs conversion functions between baseband signals and bit streams according to the system's physical layer specifications. For instance, when transmitting data, transceiver 1001 encodes and modulates the transmitted bit stream to generate complex-valued symbols. And when receiving data, transceiver 1001 recovers the received bit stream by demodulating and decoding the baseband signal. Furthermore, transceiver 1001 uplinks the baseband signal to an RF (radiofrequency) band signal and transmits it through an antenna, and downlinks the RF band signal received through the antenna back to a baseband signal. For this purpose, transceiver 1001 may include transmit filters, receive filters, amplifiers, mixers, oscillators, digital-to-analog converters (DACs), analog-to-digital converters (ADCs), etc. Furthermore, transceiver 1001 may include multiple transmit and receive paths. Furthermore, the transceiver 1001 may include at least one antenna array composed of multiple antenna elements. From a hardware perspective, the transceiver 1001 may be composed of digital units and analog units, and the analog units may be configured into multiple sub-units depending on the operating power, operating frequency, etc. The transceiver 1001 transmits and receives signals as described above. Therefore, the transceiver 1001 may be referred to as a "transmitting unit," a "receiving unit," or a "transceiver unit."

[0130] In addition to wireless channels, transceiver 1001 may also transmit or receive signals via backhaul networks, optical communication, Ethernet, or other wired paths. For example, transceiver 1001 may support optical communication for signaling between satellite 520 and other satellites. Satellite 520 may perform optical communication with other satellites via transceiver 1001 and by using lasers. For example, it may also support wired communication between components within satellite 520. Transceiver 1001 may convert bit streams transmitted from satellite 520 to other nodes (e.g., other access nodes, other base stations, upper-level nodes, core networks, etc.) into physical signals, and convert physical signals received from other nodes into bit streams.

[0131] Transceiver 1001 can support communication between satellite 520 and UE 510. In addition to supporting communication between satellite 520 and UE 510, transceiver 1001 can also support communication between satellite 520 and terrestrial components (e.g., network entities of NTN gateway 530 and core network 550). As a non-limiting example, the circuitry within transceiver 1001 for communication with UE 510 and the circuitry for communication with the terrestrial components (e.g., network entities of NTN gateway 530 and core network 550) can be separated from each other.

[0132] Processor 1003 can control the overall operation of satellite 520. For example, processor 1003 records and reads data in memory 1005. For example, processor 1003 transmits and receives signals via transceiver 1001. Although Figure 10 A processor is shown, but embodiments of this disclosure are not limited thereto. To perform embodiments of this disclosure, satellite 520 may include at least one processor (e.g., multiple processors). Processor 1003 may be referred to as a control unit or control means. According to embodiments of this disclosure, processor 1003 may control satellite 520 to perform at least one of the actions or methods according to embodiments of this disclosure.

[0133] Memory 1005 can store basic programs, application programs, setting information, and other data used for the operation of satellite 520. Memory 1005 can store diverse data used by at least one component (e.g., transceiver 1001, processor 1003). Data may include, for example, software and input or output data related to associated instructions. Memory 1005 can be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Furthermore, memory 1005 can provide stored data upon request from processor 1003.

[0134] According to embodiments of this disclosure, an apparatus is provided for providing access to a satellite for a non-terrestrial network (NTN), the satellite being configured to perform the functions of an enhanced node B (eNB). The apparatus may include: a memory containing instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the apparatus may be configured to: identify a store-and-forward (S&F) mode in a radio resource control (RRC) connection state with user equipment (UE), transmit a message to the UE indicating that the satellite is operating in the S&F mode, and after transmitting the message, receive a request signal from the UE related to terminating the RRC connection, and transmit an RRC connection termination message to the UE for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may include at least one of the following: an indicator indicating that the cell provided by the satellite supports S&F mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering a request to terminate the RRC connection.

[0135] According to one embodiment, the message may include a data inactivation timer for the S&F mode. The value of the data inactivation timer may be set to a shorter value than the inactivation timer used to terminate the RRC connection in a mode different from the S&F mode.

[0136] According to one embodiment, the information associated with the conditions for triggering a request to terminate the RRC connection may include at least one of the following: a list of data radio bearers (DRBs), a list of quality of service (QoS) flows, a list of Single Network Slice Selection Assistance Information (S-NSSAI), a list of bandwidth parts (BWPs), a list of physical resource blocks (PRBs), a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

[0137] According to one embodiment, the request signal may correspond to a buffer status reporting (BSR) medium access control (MAC) control element (CE) that includes the uplink data volume of the UE.

[0138] According to one embodiment, the reason value for terminating the RRC connection can represent the S&F mode.

[0139] According to embodiments of this disclosure, a user equipment (UE) is provided for performing non-terrestrial network (NTN) access. The UE may include: a memory including instructions; at least one processor; and at least one transceiver. When the instructions are executed by the at least one processor, the UE may be configured to: receive, in a radio resource control (RRC) connection state, a message from a satellite configured to perform enhanced node B (eNB) functions indicating that the satellite is operating in store-and-forward (S&F) mode; after receiving the message, transmit a request signal related to terminating the RRC connection to the satellite; and receive an RRC connection termination message from the satellite for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may contain at least one of the following: an indicator indicating that the cell provided by the satellite supports S&F mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering the request to terminate the RRC connection.

[0140] According to one embodiment, the message may include a data inactivation timer for the S&F mode. The value of the data inactivation timer may be set to a shorter value than the inactivation timer used to terminate the RRC connection in a mode different from the S&F mode.

[0141] According to one embodiment, the information associated with the conditions for triggering a request to terminate the RRC connection may include at least one of the following: a list of data radio bearers (DRBs), a list of quality of service (QoS) flows, a list of Single Network Slice Selection Assistance Information (S-NSSAI), a list of bandwidth parts (BWPs), a list of physical resource blocks (PRBs), a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

[0142] According to one embodiment, the request signal may correspond to a buffer status reporting (BSR) medium access control (MAC) control element (CE) that includes the uplink data volume of the UE.

[0143] According to one embodiment, the reason value for terminating the RRC connection can represent the S&F mode.

[0144] According to embodiments of this disclosure, a method is provided for providing access to a non-terrestrial network (NTN) by a satellite configured to perform the functions of an enhanced node B (eNB). The method may include: identifying a store-and-forward (S&F) mode while in a radio resource control (RRC) connection state with user equipment (UE); transmitting a message to the UE indicating that the satellite is operating in the S&F mode; receiving, after transmitting the message, a request signal from the UE related to terminating the RRC connection; and transmitting an RRC connection termination message to the UE for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may contain at least one of the following: an indicator indicating that the cell provided by the satellite supports the S&F mode, information related to the validity period of the satellite's feeder link, and information related to conditions for triggering the termination of the RRC connection.

[0145] According to one embodiment, the message may include a data inactivation timer for the S&F mode. The value of the data inactivation timer may be set to a shorter value than the inactivation timer used to terminate the RRC connection in a mode different from the S&F mode.

[0146] According to one embodiment, the information associated with the conditions for triggering a request to terminate the RRC connection may include at least one of the following: a list of data radio bearers (DRBs), a list of quality of service (QoS) flows, a list of Single Network Slice Selection Assistance Information (S-NSSAI), a list of bandwidth parts (BWPs), a list of physical resource blocks (PRBs), a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

[0147] According to one embodiment, the request signal may correspond to a buffer status reporting (BSR) medium access control (MAC) control element (CE) that includes the uplink data volume of the UE.

[0148] According to one embodiment, the reason value for terminating the RRC connection can represent the S&F mode.

[0149] According to embodiments of this disclosure, a method is provided performed by user equipment (UE) for performing non-terrestrial network (NTN) access. The method may include: receiving, while in a radio resource control (RRC) connection state, a message from a satellite configured to perform enhanced node B (eNB) functions, indicating that the satellite is operating in store-and-forward (S&F) mode; transmitting, after receiving the message, a request signal related to terminating the RRC connection to the satellite; and receiving, from the satellite, an RRC connection termination message for terminating the RRC connection. The RRC connection termination message may contain a reason value for terminating the RRC connection. The message may contain at least one of the following: an indicator indicating that the cell provides S&F mode support by the satellite, information related to the validity period of the satellite's feeder link, and information related to conditions for triggering the request to terminate the RRC connection.

[0150] According to one embodiment, the message may include a data inactivation timer for the S&F mode. The value of the data inactivation timer may be set to a shorter value than the inactivation timer used to terminate the RRC connection in a mode different from the S&F mode.

[0151] According to one embodiment, the information associated with the conditions for triggering a request to terminate the RRC connection may include at least one of the following: a list of data radio bearers (DRBs), a list of quality of service (QoS) flows, a list of Single Network Slice Selection Assistance Information (S-NSSAI), a list of bandwidth parts (BWPs), a list of physical resource blocks (PRBs), a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

[0152] According to one embodiment, the request signal may correspond to a buffer status reporting (BSR) medium access control (MAC) control element (CE) that includes the uplink data volume of the UE.

[0153] According to one embodiment, the reason value for terminating the RRC connection can represent the S&F mode.

[0154] The methods of the embodiments described in the claims or specification of this disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0155] In the case of software implementation, a computer-readable storage medium may be provided that stores one or more programs (software modules). The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs contain instructions that cause the electronic device to perform the methods of the embodiments described in the claims or specification of this disclosure.

[0156] Such programs (software modules, software) can be stored in random access memory, including non-volatile memory such as flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they can be stored in a memory consisting of some or all of these components. Furthermore, multiple components of the memory may be included.

[0157] Furthermore, the program can be stored on an attachable storage device accessible via a communication network consisting of a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. Such a storage device can be connected to the apparatus executing embodiments of this disclosure via an external port. Additionally, additional storage devices on the communication network can also be connected to the apparatus executing embodiments of this disclosure.

[0158] In the specific embodiments of this disclosure described above, the constituent elements included in this disclosure are represented in a singular or plural form depending on the specific embodiment presented. However, the singular or plural representation is chosen for ease of explanation and suitably to the presented situation, and this disclosure is not limited to a singular or plural constituent element; even constituent elements represented in a plural form may be constituted in a singular form, or even constituent elements represented in a singular form may be constituted in a plural form.

[0159] Furthermore, although specific embodiments have been described in the foregoing description of this disclosure, various modifications may be made without departing from the scope of this disclosure.

Claims

1. An apparatus for providing access to a satellite for a non-terrestrial network, the satellite being configured to perform the functions of an enhanced Node B, characterized in that, The device includes: Memory, including instructions, At least one processor, and At least one transceiver; When the instructions are executed by the at least one processor, the device is configured to: While connected to the user equipment's radio resource control system, identify the store-and-forward mode. The user equipment is transmitted a message indicating that the satellite is operating in the store-and-forward mode. After transmitting the message, a request signal related to terminating the Radio Resource Control connection is received from the user equipment, and Transmit a Radio Resource Control Connection Release Message to the User Equipment for releasing the Radio Resource Control Connection; The Radio Resource Control (RRC) connection termination message includes a reason value for terminating the RRC connection. The message includes at least one of the following: an indicator indicating that the cell provided by the satellite supports store-and-forward mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering a request to terminate the radio resource control connection.

2. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The message includes a data inactivation timer for the store-and-forward mode. The value of the data inactivation timer is set to a shorter value than the inactivation timer used to terminate the radio resource control connection in a mode different from the store-and-forward mode.

3. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The information associated with the conditions used to trigger the request to terminate the radio resource control connection includes at least one of the following: a list of data radio bearers, a list of quality of service streams, a list of single network slice selection assistance information, a list of bandwidth portions, a list of physical resource blocks, a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

4. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The request signal corresponds to the media access control element, which includes the cached status report of the uplink data volume of the user equipment.

5. The apparatus for providing satellite access to non-terrestrial networks according to claim 1, characterized in that, The reason value for terminating the radio resource control connection indicates the store-and-forward mode.

6. A user equipment for performing non-terrestrial network access, characterized in that, include: Memory, including instructions, At least one processor, and At least one transceiver; When the instruction is executed by the at least one processor, the user equipment is configured to: In the radio resource control connection state, a message indicating that the satellite is operating in store-and-forward mode is received from a satellite configured to perform the functions of an enhanced Node B. Upon receiving the message, a request signal related to terminating the radio resource control connection is transmitted to the satellite, and Receive from the satellite a Radio Resource Control Connection Release Message for releasing the Radio Resource Control Connection; The Radio Resource Control (RRC) connection termination message includes a reason value for terminating the RRC connection. The message includes at least one of the following: an indicator indicating that the cell provided by the satellite supports store-and-forward mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering a request to terminate the radio resource control connection.

7. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The message includes a data inactivation timer for the store-and-forward mode. The value of the data inactivation timer is set to a shorter value than the inactivation timer used to terminate the radio resource control connection in a mode different from the store-and-forward mode.

8. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The information associated with the conditions used to trigger the request to terminate the radio resource control connection includes at least one of the following: a list of data radio bearers, a list of quality of service streams, a list of single network slice selection assistance information, a list of bandwidth portions, a list of physical resource blocks, a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

9. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The request signal corresponds to the media access control element, which includes the cached status report of the uplink data volume of the user equipment.

10. The user equipment for performing non-terrestrial network access according to claim 6, characterized in that, The reason value for terminating the radio resource control connection indicates the store-and-forward mode.

11. A method for providing non-terrestrial network access, performed by a satellite configured to perform the functions of an enhanced Node B, characterized in that, The method includes: While connected to the user equipment's radio resource control system, identify actions in store-and-forward mode. The action of transmitting a message to the user equipment indicating that the satellite is operating in the store-and-forward mode. After transmitting the message, the action of receiving a request signal from the user equipment related to terminating the radio resource control connection, and The action of transmitting a Radio Resource Control Connection Release Message to the User Equipment for releasing the Radio Resource Control Connection; The Radio Resource Control (RRC) connection termination message includes a reason value for terminating the RRC connection. The message includes at least one of the following: an indicator indicating that the cell provided by the satellite supports store-and-forward mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering a request to terminate the radio resource control connection.

12. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The message includes a data inactivation timer for the store-and-forward mode. The value of the data inactivation timer is set to a shorter value than the inactivation timer used to terminate the radio resource control connection in a mode different from the store-and-forward mode.

13. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The information associated with the conditions used to trigger the termination of the radio resource control connection includes at least one of the following: a data radio bearer list, a quality of service stream list, a list of single network slice selection assistance information, a list of bandwidth portions, a list of physical resource blocks, a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

14. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The request signal corresponds to the media access control element, which includes the cached status report of the uplink data volume of the user equipment.

15. The method for providing non-terrestrial network access performed by a satellite according to claim 11, characterized in that, The reason value for terminating the radio resource control connection indicates the store-and-forward mode.

16. A method for performing non-terrestrial network access, executed by a user equipment, characterized in that, include: In the radio resource control connection state, the action of receiving a message from a satellite configured to perform the functions of an enhanced Node B, indicating that the satellite is operating in store-and-forward mode. Upon receiving the message, the action of transmitting a request signal to the satellite related to terminating the radio resource control connection, and The action of receiving a radio resource control connection termination message from the satellite to terminate the radio resource control connection; The Radio Resource Control (RRC) connection termination message includes a reason value for terminating the RRC connection. The message includes at least one of the following: an indicator indicating that the cell provided by the satellite supports store-and-forward mode, information related to the validity period of the satellite's feeder link, and information related to the conditions for triggering a request to terminate the radio resource control connection.

17. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The message includes a data inactivation timer for the store-and-forward mode. The value of the data inactivation timer is set to a shorter value than the inactivation timer used to terminate the radio resource control connection in a mode different from the store-and-forward mode.

18. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The information associated with the conditions used to trigger the request to terminate the radio resource control connection includes at least one of the following: a list of data radio bearers, a list of quality of service streams, a list of single network slice selection assistance information, a list of bandwidth portions, a list of physical resource blocks, a list of sub-bands, a threshold for uplink data volume, and a threshold for a channel quality-related metric.

19. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The request signal corresponds to the media access control element, which includes the cached status report of the uplink data volume of the user equipment.

20. The method for performing non-terrestrial network access executed by a user equipment according to claim 16, characterized in that, The reason value for terminating the radio resource control connection indicates the store-and-forward mode.

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