Method and apparatus of store and forward in ntn

Abstract

Systems and methods are disclosed that relate to a store-and-forward service for downlink data in wireless communications system. In one embodiment, a method performed by a User Equipment (UE) comprises receiving an indication of a store-and-forward service via which downlink data for the UE will be stored at a network node while a network connection between the UE and a radio access network (RAN) of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during connection or resuming the a connection with the network node. The method further comprises, based on the received indication, maintaining a certain status while the network connection is unavailable and, upon or during connection or resuming a connection with the network node, receiving, from the network node, one or more downlink data packets stored by the network node for the store-and-forward service while the network connection was unavailable.

Description

METHOD AND APPARATUS OF STORE AND FORWARD IN NTNRELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 633,470, filed April 12, 2024, the disclosure of which is hereby incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to a Non-Terrestrial Network (NTN) and, more specifically, to a store-and-forward service for downlink data in an NTN.BACKGROUND

[0003] A satellite radio access network usually includes the following components:- A satellite that refers to a space-borne platform.- An earth-based gateway that connects the satellite to a base station or a core network, depending on the choice of architecture.- A feeder link that refers to the link between a gateway and a satellite.- An access link, or service link, that refers to the link between a satellite and a User Equipment (UE).

[0004] Depending on the orbit altitude, a satellite may be categorized as Low Earth Orbit (LEO), Medium Earth Orbit (MEO), or Geostationary Earth Orbit (GEO) satellite. For LEO, typical heights range from 250 - 1,500 kilometers (km), with orbital periods ranging from 90 - 120 minutes. For MEO, typical heights range from 1,500 - 35,786 km, with orbital periods, PMEO, in the range 2 hours < PMEO < 24 hours. MEO and LEO are also known as Non-Geo Synchronous Orbit (NGSO) type of satellite. For GEO, the height is at about 35,786 km, with an orbital period of 24 hours. GEO is also known as a Geo Synchronous Orbit (GSO) type of satellite.

[0005] Two basic architectures can be distinguished for satellite communication networks, depending on the functionality of the satellites in the system, namely, transparent payload and regenerative payload. For transparent payload (also referred to as bent pipe architecture), the satellite forwards the received signal between the terminal and the network equipment on the ground with only amplification and a shift from uplink frequency to downlink frequency. When applied to general 3rdGeneration Partnership Project (3GPP) architecture and terminology, the transparent payload architecture means that the next generation NodeB (gNB) is located on the ground and the satellite forwards signals / data between the gNB and the UE. For regenerative payload, the satellite includes on-board processing to demodulate and decode the received signaland regenerate the signal before sending it back to the earth. When applied to general 3 GPP architecture and terminology, the regenerative payload architecture means that the gNB is located in the satellite. In the work item for New Radio (NR) Non-Terrestrial Network (NTN) in 3GPP Release 17, only the transparent payload architecture is considered.

[0006] Figure 1 shows an example architecture of a satellite network with bent pipe transponders (i.e., the transparent payload architecture). The gNB may be integrated in the gateway or connected to the gateway via a terrestrial connection (wire, optic fiber, wireless link).

[0007] The significant orbit height means that satellite systems are characterized by a path loss that is significantly higher than what is expected in terrestrial networks. To overcome the pathloss, it is often required that the access and feeder links are operated in line-of-sight conditions, and that the UE is equipped with an antenna offering high beam directivity.

[0008] A communication satellite typically generates several beams over a given area. The footprint of a beam is usually in an elliptic shape, which has been traditionally considered as a cell (but a cell consisting of multiple beams is not precluded). The footprint of a beam is also often referred to as a spotbeam. The spotbeam may move over the earth surface with the satellite movement (and the earth’s rotation) or may be earth fixed with some beam pointing mechanism used by the satellite to compensate for its motion. The size of a spotbeam depends on the system design and may range from tens of kilometers to a few thousands of kilometers.

[0009] The NTN beam may, in comparison to the beams observed in a terrestrial network, provide a very wide footprint and may cover an area outside of the area defined by the served cell. Beam covering adjacent cells will overlap and cause significant levels of intercell interference, resulting from the slow decrease of the signal strength in the outwards radial direction. This is due in part to the high elevation angle and long distance to the network-side (satellite-borne) transceiver, which, compared with terrestrial cells, results in a comparatively small relative difference between the distance from the cell center to the satellite and the distance from a point at the cell edge to the satellite. To overcome the large levels of interference, a typical approach in NTN is to configure different cells with different carrier frequencies and polarization modes.

[0010] Three types of beams or cells are supported in NTN, namely, Earth-fixed beams / cells, quasi-Earth-fixed beams / cells, and Earth-moving beams / cells. Earth-fixed beams / cells are provisioned by beam(s) continuously covering the same geographical areas all the time (e.g., in the case of GEO satellites). Quasi-earth-fixed beams / cells are provisioned by beam(s) covering one geographic area for a limited period and a different geographic area during another period (e.g., in the case of NGSO satellites generating steerable beams). Earth-moving beams / cells areprovisioned by beam(s) whose coverage area slides over the earth surface (e.g., in the case of NGSO satellites generating fixed or non-steerable beams).

[0011] Throughout the present disclosure, the terms “beam” and “cell” are hereinafter used interchangeably, unless explicitly noted otherwise.

[0012] Of the three above cell types, quasi-Earth-fixed cells and moving cells seem to be the ones most promising for actual deployment. In the case of moving cells, each cell (the footprint of its beam(s)) moves across the surface of the earth as its serving satellite moves along its orbit.

[0013] In the case of quasi-Earth-fixed cells, the cell area (as the name implies) remains fixed to the same geographical area, regardless of satellite movements. To enable this, a serving satellite has to have means for dynamically directing its beam(s), so that the same area of the earth is covered despite the satellite’s movement. However, since the satellites orbit around the Earth, the same satellite will only be able to cover the same area on the Earth for a limited time, unless the satellite is in a geostationary orbit (and note that LEO satellites have the most traction in the satellite communication industry). This means that different satellites will have the task of covering a certain geographical cell area at different time periods. When this task is switched from one satellite to another, this in principle means that one cell is replaced by another, although covering the same area (often referred to as a cell switch). As a consequence, all UEs connected in the old cell (i.e., UEs in RRC CONNECTED state) have to be handed over (or otherwise moved, e.g. using Radio Resource Control (RRC) connection reestablishment) from the old to the new cell, and all UEs camping on the old cell (i.e., UEs in RRC IDLE or RRC INACTIVE state) have to perform cell reselection to the new cell.

[0014] A similar situation occurs in conjunction with feeder link switches, i.e. when the serving satellite remains the same, but its connection to the ground changes from one (old) gateway (GW) / gNB to another (new) GW / gNB. Also, in this case, there is switch between an old cell and a new cell (i.e. the old cell is replaced by a new cell).

[0015] In terms of such cell switches, there are two alternative principles: (1) hard switch; and (2) soft switch. With hard switch, there is an instantaneous switch from the old to the new cell, i.e., the new cell appears at the same time as the old cell disappears. This makes completely seamless (i.e., interruption free) handover in practice impossible and creates a situation which may lead to overload of the access resources in the new cell, due to potential access attempt peaks when many UEs try to access the new cell right after the cell switch. With soft switch, there is a time period during which the new and the old cell coexist (i.e. overlap), covering the same geographical area. This coexistence / overlap period allows some time for connected UEs to be handed over and for camping UEs to reselect to the new cell, which facilitates distribution of the access load in thenew cell and thereby also provides better conditions for handovers with shorter interruption time. Soft switch is likely to be the most prevalent cell switch principle in quasi-earth-fixed cell deployments.

[0016] In 3GPP, the 5thGeneration (5G) System (5GS) uses New Radio (NR), which is a new generation’s radio access technology intended to serve use cases such as enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), Narrowband Internet of Things (NB-IOT), and massive Machine Type Communication (mMTC). 5G includes the NR access stratum interface and the 5G Core Network (5GC). The NR physical and higher layers reuse parts of the Long Term Evolution (LTE) specification, and to that add needed components when motivated by new use cases. There has been a lot of discussions in 3GPP in the last few years on how to specify technologies to cover / address use cases for Machine-to-Machine (M2M) and / or Internet of Things (loT). In Release 13 enhancements to support Machine-Type Communications (MTC) were specified introducing new UE categories Ml (Cat-Mi) and NB1 (Cat-NBl) to support reduced maximum bandwidth of up to six (6) Physical Resource Blocks (PRBs) in eMTC work item and narrowband carrier in NB-IoT work item specifying a new radio interface, respectively.

[0017] Discontinuous coverage refers to the situation where the visibility of a satellite or group of satellites, commonly LEO, from a certain ground point is limited in time leading to periods without any satellite network coverage. The rapid movement of NGSO satellites around Earth is the cause of this time limitation and its length depends on the characteristics of the satellite constellation (e.g., structure, total number of satellites, number of orbital planes, or satellites per plane) and UE (e.g., minimum elevation angle, or local radio conditions). Hence, the use of partial, sparse, or incomplete constellations where the number of satellites is not enough to provide continuous coverage in a region will result in satellite network coverage gaps. This might be a usual case in early loT NTN deployments due to the relaxed delay requirements and traffic profiles typical of loT applications.

[0018] During Release 17, a UE centric solution to evaluate coverage gaps was standardized in 3GPP for loT NTN. The assistance information sent to the UE includes satellite mean ephemeris in Two-Line Element (TLE) format, satellite ID, and coverage information. Additionally, in quasiEarth fixed cell deployments, the network may provide the absolute start serving time (T-service- start) instead of the satellite’s ephemeris. This information is used by the UE to estimate when the same or next satellite will be visible from its current location so that it can enter a deep sleep state in between the satellite passes when there is no available coverage.

[0019] There are multiple differences between “legacy” LTE and the procedures and channels defined for eMTC or NB-IoT. Some important differences include a new physical downlink control channel, i.e., MTC Physical Downlink Control Channel (MPDCCH) used in eMTC and NB-IoT Physical Downlink Control Channel (NPDCCH) used in NB-IoT.

[0020] 3GPP Release 12 initiated the work on eMTC, also often referred to as LTE-M, and specified the first low-complexity UE category 0 (Cat-0). Cat-0 supports a reduced peak data rate of 1 Mbps, single antenna and Half Duplex Frequency Division Duplex (HD FDD) operation.

[0021] In Release 13 the work accelerated with the introduction of the Cat-Mi UE category. It supports a further reduced complexity, and Coverage Enhanced (CE) operation. The additional cost reduction came from a reduced transmission and reception bandwidth of 1.08 Megahertz (MHz), equivalent to six 180 kHz PRBs. The introduction of a lower UE power class of 20 decibel- milliwatts (dBm), in addition to the 23 dBm power class, further facilitates a lower UE complexity.

[0022] Because of the reduction in bandwidth, a new narrowband physical downlink control channel, the MPDCCH, was introduced as a substitute for the wideband legacy Physical Downlink Control Channel (PDCCH) and the Enhanced PDCCH (EPDCCH). The Cat-Mi UEs monitor MPDCCH in a narrowband (NB), which is defined by six (6) adjacent PRBs.

[0023] eMTC supports an Maximum Coupling Loss (MCL) that is 20 decibels (dB) larger than the normal MCL of LTE. This is achieved mainly through time repetition and a relaxed acquisition time of the physical channels and signals. The primary and secondary synchronization signals (PSS and SSS) are fully reused from LTE and extended coverage is achieved by means of increased acquisition time.

[0024] For the Physical Broadcast Channel (PBCH), the MPDCCH, the Physical Uplink Control Channel (PUCCH), and the data channels, that is, the Physical Uplink Shared Channel (PUSCH) and Physical Downlink Shared Channel (PDSCH), the desired coverage enhancement is achieved through so-called time repetition of a transmission block.

[0025] In LTE Releases 14 and 15, eMTC was further enhanced to support a more diversified set of applications and services. A new UE category Cat-M2 was e.g., specified. The performance of eMTC Release 15 meets the IMT-2020 5G requirements for the massive loT use case.

[0026] The work in 3GPP on eMTC was continued in Release 16 and is further evolved also in Release 17 and Release 18.

[0027] At the 3GPP RAN#70 meeting, a new Release 13 work item named Narrowband loT (NB-IoT) was approved. The objective of the new loT related work items approved for release 13 was to specify a radio access for cellular loT that addresses improved indoor coverage, support formassive number of low throughput devices, not sensitive to delay, ultra-low device cost, low device power consumption and (optimized) network architecture.

[0028] NB-IoT can be described as a narrowband version of LTE. Similar to eMTC, NB-IoT makes use of increased acquisition times and time repetitions to extend the system coverage. The repetitions can be seen as a third level of retransmissions added at the physical layer as a complement to those at Medium Access Control (MAC) Hybrid Automatic Repeat Request (HARQ) and Radio Link Control (RLC) Automatic Repeat Request (ARQ). A NB-IoT downlink carrier is defined by 12 Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers, each of 15 kilohertz (kHz), giving a total baseband bandwidth of 180 kHz. When multiple carriers are configured, several 180 kHz carriers can be used, e.g., for increasing the system capacity, intercell interference coordination, load balancing, etc. This design gives NB-IoT a high deployment flexibilitySUMMARY

[0029] Systems and methods are disclosed that relate to a store-and-forward service for downlink data in wireless communications system such as, for example, a Non- Terrestrial Network (NTN). In one embodiment, a method performed by a User Equipment (UE) for reception of data via a store-and-forward service of a wireless communications system comprises receiving an indication of a store-and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE and a radio access network (RAN) of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node. The method further comprises, based on the received indication, maintaining a certain status while the network connection between the UE and the RAN of the wireless communications system is unavailable. The method further comprises, upon or during connection or resuming a connection with the network node, receiving, from the network node, one or more downlink data packets stored by the network node for the store-and-forward service while the network connection between the UE and the RAN of the wireless communication system was unavailable. In this manner, a store and forward service for downlink data is provided.

[0030] In one embodiment, the network node is an NTN node in the RAN of the wireless communications system.

[0031] In one embodiment, the certain status is a certain Radio Resource Control (RRC) status.

[0032] In one embodiment, receiving the indication of the store-and-forward service comprises receiving the indication of the store-and-forward service from a core network node in a core network of the wireless communications system via a serving network node of the UE. In one embodiment, the network node from which the UE receives the one or more downlink data packets for the store-and-forward service is the serving network node from which the UE received the indication of the store-and-forward service. In another embodiment, the network node from which the UE receives the one or more downlink data packets for the store-and-forward service is a network node other than the serving network node from which the UE received the indication of the store-and-forward service. In one embodiment, the method further comprises sending, to the core network node, assistance information for the store-and-forward service, wherein the assistance information for the store-and-forward service sent from the UE to the core network node comprises any one or more of the following: an indicator indicating that the UE supports the store- and-forward service, an indicator indicating that the UE enables the store-and-forward service, an identity of the UE, an identity of a UE context of the UE, a position of the UE, a time period for transmitting the one or more data packets for the UE from the network node involved in the store- and-forward service to the UE, and a UE context of the UE. In one embodiment, receiving the indication of the store-and-forward service comprises receiving assistance information for the store-and-forward service, wherein the assistance information for the store-and-forward service comprises any one or more of the following: an identity of the network node providing the store- and-forward service to the UE, information that indicates a time period during which the one or more downlink data packets for the store-and-forward service will be sent from the network node to the UE, and information that indicates a time period during which the UE will be out of network coverage.

[0033] In one embodiment, the method further comprises, prior to receiving the one or more data packets for the store-and-forward service, sending an indication or request to the network node to send the one or more data packets for the store-and-forward service.

[0034] Corresponding embodiments of a UE are also disclosed. In one embodiment, a UE for reception of data via a store-and-forward service of a wireless communications system is adapted to receive an indication of a store-and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a RAN of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node. The UE is further adapted to, based on the received indication, maintain a certain status while the network connection between the UE and the RAN of the wireless communicationssystem is unavailable. The UE is further adapted to, upon or during connection or resuming a connection with the network node, receive, from a network node, one or more downlink data packets stored by the network node for the store-and-forward service while the network connection between the UE and the RAN of the wireless communication system was unavailable.

[0035] In one embodiment, a UE for reception of data via a store-and-forward service of a wireless communications system comprises a communication interface comprising a transmitter and a receiver. The UE further comprises processing circuitry associated with the communication interface, the processing circuitry configured to cause the UE to receive an indication of a store- and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a RAN of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node. The processing circuitry is further configured to cause the UE to, based on the received indication, maintain a certain status while the network connection between the UE and the RAN of the wireless communications system is unavailable. The processing circuitry is further configured to cause the UE to, upon or during connection or resuming a connection with the network node, receive, from a network node, one or more downlink data packets stored by the network node for the store-and-forward service while the network connection between the UE and the RAN of the wireless communication system was unavailable.

[0036] Embodiments of a method performed by a network node for a wireless communications system for a downlink store-and-forward service are also disclosed. In one embodiment, a method performed by a network node for a wireless communications system for a downlink store-and-forward service comprises receiving, from a core network node in a core network of the wireless communications system, one or more downlink data packets for a UE to be sent to the UE via a store-and-forward service. The method further comprises storing the one or more downlink data packets and transmitting, to the UE, the one or more data packets stored for the UE for the store-and-forward service upon or during the UE connecting to the network node or resuming a connection with the network node.

[0037] In one embodiment, the method further comprises, prior to transmitting the one or more data packets for the store-and-forward service to the UE, transmitting a paging message or other signaling message to the UE that indicates the presence of the stored one or more data packets for the UE for the store-and-forward service.

[0038] In one embodiment, the method further comprises, prior to transmitting the one or more data packets for the store-and-forward service to the UE, receiving, from the UE, an indication or request to send the one or more data packets for the store-and-forward service.

[0039] In one embodiment, the method further comprises sending, to the core network node, assistance information for the store-and-forward service, wherein the assistance information for the store-and-forward service sent from the network node to the core network node comprises any one or more of the following: an indicator indicating that the network node supports the store-and- forward service, an indicator indicating that the network node enables the store-and-forward service, ephemeris data of a satellite associated to the network node, an identity of the network node, a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE, and a non-coverage time period.

[0040] In one embodiment, the network node is an NTN node.

[0041] Corresponding embodiments of a network node are also disclosed. In one embodiment, a network node for a wireless communications system for a downlink store-and- forward service is adapted to receive, from a core network node in a core network of the wireless communications system, one or more downlink data packets for a UE to be sent to the UE via a store-and-forward service. The network node is further adapted to store the one or more downlink data packets and transmit, to the UE, the one or more data packets stored for the UE for the store- and-forward service upon or during the UE connecting to the network node or resuming a connection with the network node.

[0042] In one embodiment, a network node for a wireless communications system for a downlink store-and-forward service comprises processing circuitry configured to cause the network node to receive, from a core network node in a core network of the wireless communications system, one or more downlink data packets for a UE to be sent to the UE via a store-and-forward service, store the one or more downlink data packets, and transmit, to the UE, the one or more data packets stored for the UE for the store-and-forward service upon or during the UE connecting to the network node or resuming a connection with the network node.

[0043] Embodiments of a method performed by a core network node or gateway for a wireless communications system for a downlink store-and-forward service are also disclosed. In one embodiment, a method performed by a core network node or gateway for a wireless communications system for a downlink store-and-forward service comprises determining to send downlink data packets to a UE via a store-and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a RAN of the wireless communications system is unavailable and subsequently forwarded to the UE uponor during establishment of a new network connection or resuming the network connection with the network node. The method further comprises sending, to the UE, an indication of the store-and- forward service before the network connection between the UE and RAN is unavailable and sending, to a network node, one or more downlink data packets for UE to be sent to the UE via the store-and-forward service.

[0044] In one embodiment, sending the indication of the store-and-forward service to the UE comprises sending the indication of the store-and-forward service to the UE via a serving network node of the UE. In one embodiment, the serving network node of the UE is an NTN node.

[0045] In one embodiment, the indication of the store-and-forward service sent to the UE comprises any one or more of the following: an identity of the network node providing the store- and-forward service to the UE, information that indicates a time period during which the one or more downlink data packets for the store-and-forward service will be sent from the network node to the UE, and information that indicates a time period during which the UE will be out of network coverage.

[0046] In one embodiment, the indication of the store-and-forward service sent to the UE explicitly or implicitly indicates that the UE is to maintain a certain status when a network connection is unavailable.

[0047] In one embodiment, the method further comprises, prior to sending the one or more downlink data packets to the network node, sending, to the network node, a request for the network node to provide the store-and-forward service for downlink data packets for the UE and receiving, from the second network node, a response that indicates that the network node is willing and able to provide the store-and-forward service for downlink data packets for the UE.

[0048] In one embodiment, the method further comprises receiving, from a serving network node of the UE, first assistance information for the store-and-forward service for downlink data packets for the UE. In one embodiment, the first assistance information comprises a UE context of the UE.

[0049] In one embodiment, the method further comprises obtaining, from the UE, second assistance information for the store-and-forward service for downlink data packets for the UE, wherein the second assistance information for the store-and-forward service obtained from the UE comprises any one or more of the following: an indicator indicating that the UE supports the store- and-forward service, an indicator indicating that the UE enables the store-and-forward service, an identity of the UE, an identity of a UE context of the UE, a position of the UE, a time period for transmitting the one or more data packets for the UE from the network node involved in the store- and-forward service to the UE, and a UE context of the UE.

[0050] In one embodiment, the method further comprises obtaining, from the network node, third assistance information for the store-and-forward service for downlink data packets for the UE, wherein the third assistance information comprises any one or more of the following: an indicator indicating that the network node supports the store-and-forward service, an indicator indicating that the network node enables the store-and-forward service, ephemeris data of a satellite associated to the network node, an identity of the network node, a time period for transmitting the one or more data packets for the UE from the network node involved in the store- and-forward service to the UE, and a non-coverage time period.

[0051] In one embodiment, the determining is based on the assistance information.

[0052] Corresponding embodiments of a core network node or gateway are also disclosed. In one embodiment, a core network node or gateway for a wireless communications system for a downlink store-and-forward service is adapted to determine to send downlink data packets to a UE via a store-and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a RAN of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node. The core network node or gateway is further adapted to send, to the UE, an indication of the store-and- forward service before the network connection between the UE and RAN is unavailable and send, to a network node, one or more downlink data packets for UE to be sent to the UE via the store- and-forward service.BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0054] Figure 1 shows an example architecture of a satellite network with bent pipe transponders (i.e., the transparent payload architecture).

[0055] Figure 2 shows a typical scenario and corresponding use case for store-and-forward in the uplink (UL).

[0056] Figures 3 and 4 show exemplary scenarios for store-and-forward in the downlink (DL), in accordance with embodiments of the present disclosure.

[0057] Figure 5 illustrates an example of available and unavailable time period for the store- and-forward service, in accordance with embodiments of the present disclosure.

[0058] Figure 6 illustrates a procedure for setup for a store-and-forward service for downlink data for a User Equipment (UE), in accordance with embodiments of the present disclosure.

[0059] Figure 7 illustrates an exemplary procedure for a store-and-forward service for downlink data for a UE, in accordance with embodiments of the present disclosure.

[0060] Figure 8 shows an example of a communication system in accordance with some embodiments.

[0061] Figure 9 shows a UE in accordance with some embodiments.

[0062] Figure 10 shows a network node in accordance with some embodiments.

[0063] Figure 11 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized.DETAILED DESCRIPTION

[0064] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0065] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0066] The standardization of Non-Terrestrial Network (NTN) technologies continues in 3rdGeneration Partnership Project (3GPP) with the following two work items RP-234077, New WID: Non-Terrestrial Networks (NTN) for Internet of Things (loT) Phase 3 and RP-234078, New WID: Non-Terrestrial Networks (NTN) for NR Phase 3 for NR and LTE, respectively. The justification for these enhancements is the necessities of the commercial deployments that are ongoing at the moment of writing. Based on real deployment or deployment plans, further evolution of New Radio (NR) and loT NTN is required. The objectives included in the Internet of Things (loT) NTN Release 19 Work Item Description (WID) RP-234077, include, among other things, the following:• Support of Store&Forward (S&F) satellite operation with full eNB as regenerative payload, therefore: o Define the necessary enhancements into E-UTRAN (network & UE) to support S&F operation for delay -tolerant services [RAN3, RAN2, RAN4]o At least specify necessary enhancements, e.g., related to SI protocol, especially to address the feeder link switch over as needed [RAN3]Note: Strive to minimise UE impact.Note: Coordination with SA2 (Rel-19 SA2 led Sat- Arch ph3 SI) is needed on the detail requirements (e.g., traffic type, or QoS parameters for S&F), network architecture (e.g., whether consider (partial) core network on satellite) etc.; further coordination with CT1 might be required

[0067] The store and forward architecture for NTN involves the use of network nodes as satellites to relay communication signals between terrestrial User Equipment (UE) and the Core Network (CN). This architecture is designed to extend the coverage and capacity of traditional terrestrial networks, particularly in remote or underserved areas.

[0068] The store and forward mechanism allows the NTN to temporarily store incoming data before transmitting it to the next hop in the network, which could be another relay node (e.g., thanks to inter-satellite links) or the core network itself. This enables the NTN to overcome the inherent latency and intermittent connectivity associated with non-terrestrial communication links.

[0069] The store-and-forward architecture is particularly useful in scenarios where the NTN is used to provide connectivity in areas with limited terrestrial infrastructure, such as remote rural or maritime environments. This mechanism, the NTN, including next generation NodeB (gNB), node or satellite can efficiently manage the transmission of data between UEs and the core network, even in challenging communication conditions, i.e., areas where satellites cannot be connected to ground stations. From a business perspective, this architecture improves ground segment affordability by enabling operation with fewer ground-stations and a more robust operation of the satellite under intermittent feeder link operation. This is specifically well-suited for delay-tolerant loT applications that do not require continuous connectivity.

[0070] The typical scenario and corresponding use case for store-and-forward in the uplink (UL) is illustrated in Figure 2. In the simplified figures, at TO, the gNB (on satellite) has connection to the UE but no connection to the CN (gateway on ground), and the gNB may receive and store (the gNB has storage capability) UL data transmitted by the UE. At Tl, the gNB does not have a connection to the UE (or still has connection to the UE) but has a connection to the CN, and the gNB may forward the stored data previously received on the UL from the UE to the CN.

[0071] There currently exist certain challenge(s). Store-and-forward operation as described above mainly considers a particular scenario, i.e., how the satellite stores the UL data from the UE when the satellite loses the connection to the CN and forwards the stored data to the CN when the connection to gateway is resumed. Thus, the existing store-and-forward operation may be referred to as to as UL store-and-forward service or operation.

[0072] However, the architecture may also support the store-and-forward operation for downlink (DL) data. As illustrated in Figure 3, at time TO, the satellite has a connection to the CN but no connection to the UE, which may be referred to as discontinuous coverage or no coverage. Then, at time Tl, the satellite does not have a connection to the CN (or still has a connection to the CN, which is a particular example as shown in Figure 4, which does not impact the issues and the solutions of the present disclosure) but has or has resumed a connection to the UE. In reality, the occurrence of this scenario is just as likely as the scenario in Figure 2 described above. On top of that, the UE is served by the CN, e.g., providing UE context to the CN through the same New Radio (NR) base station (i.e., gNB) / satellite or different gNB / satellite, which is illustrated before time TO in the figure.

[0073] In this scenario, a use case is that the CN may send the data for the UE to the gNB at time TO and the gNB first stores the data and then forwards the data to the UE at time Tl . Given the known trajectory of the satellite, one of the benefits of the use case is the CN may offload data in advance before losing satellite connection. Another one of the benefits of the use case is the operation may shorten the latency of data transmission in case of discontinuous coverage for example. To enable this use case, which is referred to herein as “early store-and-forward operation” or “DL store-and-forward operation” and described in the present disclosure, it is desirable to exploit new solutions and solve new issues different from UL store-and-forward.

[0074] Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. Embodiments of the disclosed solution(s) address the above-described problems by introducing a mechanism for store-and-forward operation in a NTN / loT NTN scenario, for a UE (a NR NTN UE or a loT NTN UE) served by a first cell (Celli), which in turn is served or managed or operated by more than one gNB and further managed or operated by a CN.

[0075] In embodiments of the present disclosure, a CN (e.g., by a gateway on ground) may provide at least one data packet, which may be associated with a store-and-forward service, to a gNB (e.g., on board satellite), with respect to assistance information of the gNB and the UE to be involved in the store-and-forward service.

[0076] Further, the CN may set up the UE context and provide at least one data packet, which may be associated with a store-and-forward service, to a gNB before it provides coverage to the UE. Yet further, the CN may indicate to the gNB to discard the early “stored” data. Alternatively or additionally, the “stored” data is discarded according to a specified or signaled validity condition or a signaled or specified validity timer (aka a validity counter). In embodiments of the present disclosure, the gNB may handle, including receiving, storing / postponing transmission, andforwarding, the at least one data packet , which may be associated with a store-and-forward service as requested by the CN. This handling may include acquiring assistance information for store- and-forward service from the CN.

[0077] In embodiments of the present disclosure, the UE may be aware of a store-and-forward service as indicated by the CN before a store-and-forward service is initiated by the CN, which may include acquiring assistance information for store-and-forward service from the CN and the gNB. To this end, the UE maintains a certain status (e.g., a certain Radio Resource Control (RRC) status) even with no connection to the gNB until the UE receives the postponed transmission of the at least one data packet after the gNB enables the connection to the UE.

[0078] In case of available inter-satellite link between at the least two satellites, one gNB may signal a message indicating or requesting to operate at least one of the data store-and-forward service or the data forwarding service to another gNB . The gNB that receives the message may accept or reject the message.

[0079] Embodiments of the present disclosure may include any one or more of the following aspects:• CN manages UE context before and during the time span in which no gNB serves UE;• CN requests and triggers gNB and UE for store-and-forward service;• gNB, with information provided by CN, provides UE data associated with store-and- forward service;• UE, with information provided by CN, manages gNB to receive data associated with store- and-forward service.

[0080] Certain embodiments may provide one or more of the following technical advantage(s).Embodiments of the present disclosure may enable the use case of DL store-and-forward.

[0081] Embodiments of the proposed solution(s) are described herein mainly in terms of NR NTN, but the solution(s) is equally applicable to loT NTN, 6thGeneration (6G) NTN, or the like. Adapting the solution description to loT NTN implies minor adjustments such as straightforward changes of terminology, e.g. that a base station (BS) should be considered to be an evolved NodeB (eNB) rather than a gNB, and that the inter-BS communication protocol is X2AP instead of XnAP.

[0082] In the present disclosure, the term “satellite” is often used even when a more appropriate term would be “gNB associated with the satellite” and it may also be called as a satellite node, satellite access node (SAN), an NTN node, node in space, etc. Here, a gNB associated with a satellite might include both a regenerative satellite, where the gNB is the satellite payload, i.e. the gNB is integrated with the satellite or gNB onboard the satellite, or a transparentsatellite, where the satellite payload is a relay and gNB is on the ground (i.e. the satellite relays the communication between the gNB on the ground and the UE).

[0083] The term node is used herein which can be a network node (e.g., a CN node or a Radio Access Network (RAN) node such as, e.g., a base station such as, e.g., a gNB) or a UE. Examples of network nodes are NodeB, Base Station (BS), Multi -Standard Radio (MSR) radio node such as MSRBS, eNodeB (eNB), gNodeB (gNB), Master eNB (MeNB), Secondary eNB (SeNB), Satellite Access Node (SAN), Location Measurement Unit (LMU), Integrated Access Backhaul (IAB) node, network controller, Radio Network Controller (RNC), Base Station Controller (BSC), relay, donor node controlling relay, Base Transceiver Station (BTS), Central Unit (e.g. in a gNB), Distributed Unit (e.g. in a gNB), Baseband Unit, Centralized Baseband, C-RAN, Access Point (AP), transmission points, transmission nodes, Transmission Reception Point (TRP), Remote Radio Unit (RRU), Remote Radio Head (RRH), nodes in Distributed Antenna System (DAS), core network node (e.g. Mobile Switching Center (MSC), Mobility Management Entity (MME), etc. in the case of 4G or Access and Mobility Management Function (AMF), User Plane Function (UPF), Session Management Function (SMF), etc. in the case of 5G), Operations and Management (O&M), Operational Support System (OSS), Self-Organizing Network (SON) node, positioning node (e.g. Evolved Serving Mobile Location Center (E-SMLC)), etc.

[0084] The term “network node” might be a satellite in regenerative architecture, i.e. the gNB is integrated satellite or a gNB on the ground communicating a UE with support of relaying by the satellite.

[0085] The non-limiting term “UE” refers to any type of wireless device communicating with a base station (e.g., gNB) and / or with another UE in a cellular or mobile communication system. Examples of UE are target device, Device to Device (D2D) UE, Vehicular to Vehicular (V2V), machine type UE, Machine Type Communication (MTC) UE or UE capable of Machine to Machine (M2M) communication, Personal Digital Assistant (PDA), tablet, mobile terminals, smart phone, Laptop Embedded Equipment (LEE), Laptop Mounted Equipment (LME), Universal Serial Bus (USB) dongles, etc.

[0086] In the description herein, the term Non-Terrestrial Network (NTN) may, depending on the context, refer to either or both of NR NTN and loT NTN, and sometimes the term is used to refer to only NR NTN. Thus, even though the embodiments outlined below are described mainly in terms of NR based NTNs, they are equally applicable in an NTN based on LTE technology (and in particular loT NTN).

[0087] In the description herein, any expression stating that a cell performs an action (e.g., that the serving cell sends a message to the UE) should be interpreted as a simplified way of writingthat the base station (BS) serving the cell performs an action (e.g. that the BS serving the serving TN cell sends a message to the UE).

[0088] The terms “serving node”, “source node”, “serving / source node”, “ source / serving node”, “target node”, “candidate target node”, “serving BS”, “source BS”, “serving / source BS”, “source / serving BS”, “targetBS” and“candidate targetBS” may sometimes be used in the solution description. The “node” or “BS” in these terms should be understood as typically being a Radio Access Network (RAN) node in an NTN based on NR technology, LTE technology or any other Radio Access Technology (RAT) in which handover, conditional handover or another mobility or conditional mobility concept is defined. In an NR based NTN, such a RAN node may be assumed to be a gNB. In an LTE based NTN (including an loT NTN), such a RAN node may be assumed to be an eNB. Alternatives to, or refinements of, these interpretations are however also conceivable. For instance, a gNB may be an en-gNB, and if a split gNB architecture is applied (dividing the gNB into multiple separate entities or notes), the term “node” may refer to a part of the gNB, such as a gNB-Central Unit (CU) (often referred to as just CU), a gNB -Distributed United (DU) (often referred to as just DU), a gNB-CU-Control Plane (CP) or a gNB-CU-User Plane (UP). Similarly, an eNB may be an ng-eNB, and if a split eNB architecture is applied (dividing the eNB into multiple separate entities or notes), the term “node” may refer to a part of the eNB, such as an eNB-CU, an eNB-DU, an eNB-CU-CP or an eNB-CU-UP. Furthermore, the “node” in the terms may also refer to an lAB-donor, lAB-donor-CU, lAB-donor-DU, lAB-donor-CU-CP, or an IAB- donor-CU-UP.

[0089] The term “store-and-forward operation” as used herein is referred to as ‘early store- and-forward operation’ or ‘DL store-and-forward operation’ in which the base station (e.g., gNB) stores the data to be sent to the UE due to discontinuous coverage to the UE before forward such data to the UE.

[0090] In one embodiment, a CN node (e.g., an AMF, SMF, etc.) provides (e.g., via a gateway on the ground) at least one data packet associated with a store-and-forward service to a gNB (e.g., gNB2), with respect to assistance information provided to the gNB (e.g., gNB2) and a UE to be involved in the store-and-forward service.

[0091] In some embodiments, the CN node determines to confirm the store-and-forward service with the gNB and the UE, including sending a request for the store-and-forward service to the gNB (e.g., gNB2) and / or UE and starting the store-and-forward operation with respect to the gNB (e.g., gNB2) and UE if at the least one of following conditions are met:• At least one condition regarding the available time periods for the store-and-forward service, refer to Figure 5:o The gNB has connection to the CN at the least from T0_l to T0_2.■ In one example, T0_l is current time and T0_2 is a future time instant.■ In a particular example, the gNB has connection to the CN before the store-and- forward operation completion between CN and gNB. o The UE to which the data associated with a store-and-forward service is to be sent is not served by the gNB or out of the coverage of the gNB at the least from T0_l to T0_2. o The gNB has no connection to the CN at the least from Ti l to Tl_2.■ In one example, Ti l and Tl_2 are future time instants. o The UE to which the data associated with a store-and-forward service is to be sent is assumed to be served by the gNB or in the coverage the gNB at the least from Ti l to Tl_2.• Other conditions for the store-and-forward service: o Quality of Service (QoS) requirements of the data packet, e.g., delay / latency budget is delay insensitive, e.g., delay budget is above a given threshold. o Service type / traffic type / application type■ In an example, the service type / traffic type / application type is delay insensitive.■ In an example, the service type / traffic type / application type allows / supports data to be store-and-forwarded. o UE category which supports / allows the UE’s data can be store-and-forwarded o UE supports the feature of store-and-forward o Priority of the services / traffic types / applications associated with the data, which allows / supports data to be store-and-forward. o Capability of the network node, i.e., the network node (including the CN and the gNB) support store-and-forward. o Sizes of data packets or the memory size occupied by the stored data, which is below the gNB’s limitation / capability of the memory.

[0092] To apply the store-and-forward service, the CN node, in advance, signals the UE of this and acquires acknowledgement from the UE at least prior to T0_l, i.e., before the UE losses connection to any gNB (e.g., gNBl, it can be another gNB other than the gNB (e.g., gNB2) providing store-and-forward service). The signaling may further contain at the least one of the following information about the store-and-forward service including the gNB (e.g., gNB2) involved in the store-and-forward service:• The identity of the gNB provides the store-and-forward service to the UE , e.g., cell ID, satellite ID.• The estimated time period of transmitting the data packet for the UE from the gNB provides the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2.• The non-coverage time period to a UE from the gNB or any gNB, e.g., which may be started from T0_l to T0_2.

[0093] In a same way, to apply the store-and-forward service, the CN node further, in advance, indicates or signals the gNB (e.g., gNB2) of the store-and-forward service and acquires an acknowledgement from the gNB(e.g., gNB2) at least prior to T0_2, i.e., before the CN node losses connection to the gNB (e.g., gNB2). The signaling / indication may further contain any of the following information about the store-and-forward service including the UE involved in store-and- forward service, including:• The identity of the UE, e.g., UE ID.• The identity of the UE context, e.g. RAN UE NGAP ID, AMF UE NGAP ID• The position of the UE, e.g., geographic area or Tracking Area Code (TAC).• The estimated time period of transmitting the data packet for the UE from the gNB involved in the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2.• UE context, UE RRC context, e.g. the Protocol Data Unit (PDU) sessions, the QoS flow to Data Radio Bearer (DRB) mapping, UE capability, UE history information.

[0094] At the end, to apply the store-and-forward service, the CN acquires or obtains assistance information beforehand which comprises at the least one of following:• The assistance information from the network node (e.g., gNB2): o An indicator indicating that the gNB supports or does not support store-and- forward service for UEs served by the gNB. o An indicator indicating that the network operates, enables, or disables store-and- forward service for UEs served by the gNB. o Ephemeris data of satellite o The identity of the gNB which stores the data packet for the UE, e.g., cell ID, satellite ID. o The estimated time period of transmitting the data packet for the UE from the gNB involved in the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2. o The non-coverage time period from the gNB or any gNB, e.g., which may be started from T0_l to T0_2.• The assistance information from the UE: o An indicator indicating that the UE supports or does not support store-and-forward service. o An indicator indicating that the UE operates, enables, or disables store-and-forward service. o the identity of the UE, e.g., UE ID. o The identity of the UE context, e g. RAN UE NGAP ID, AMF UE NGAP ID o The position of the UE, e.g., geographic area or TAC. o The estimated time period of transmitting the data packet for the UE from the gNB involved in the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2. o UE context, UE RRC context, e.g. the PDU sessions, the QoS flow to DRB mapping, UE capability, UE history information.

[0095] In one embodiment, the UE N2 / N3 connection is suspended, and the UE NGAP ID pair and the N3 TNL information are kept even while the N2 / N3 connection is temporarily broken, e.g. between T0_l to T0_2. It is restored when the connections can be set up again, e.g. between T0_l to T0_2.

[0096] In one embodiment, the CN node is aware of various time spans including concerning the gNB (e.g., gNB2) and the UE, by acquiring / keeping / updating the valid time information which may comprise at the least one of below:• The time span of valid connection between the CN and the gNB. o The start time instant of losing connection between the CN and the gNB. o The end time instant of resuming connection between the CN and the gNB• The time span of valid connection between the gNB and the UE. o The start time instant of losing connection between the gNB and the UE. o The end time instant of resuming connection between the gNB and the UE.• The time span of enabling store-and-forward service. o The start time instant of enabling store-and-forward service. o The end time instant of enabling store-and-forward service.• Any combination of above.In one example, the start / end time and time span are defined with absolute time instant. In another example, the start / end time and time span is set along with / triggered by a pre-defined operation, e.g. handover command, or a reference time, e.g. ‘T-service’, or ‘T-serviceStart’ or a time instant when the satellite and UE reach into / outside a reference position. Further regarding the start / endtime and time span, in one option, the CN may determine such time by estimation of satellite Ephemeris and UE position. In one option, the CN may acquire such time from the association information provided by the gNB and UE.

[0097] In one embodiment, the CN sets up the UE associated connection to a gNB (e.g., gNB2) as shown in Figure 6 and provides at least one data packet associated with a store-and-forward service before it provides coverage to the UE. For serving the purpose, the CN uses the valid UE context information obtained from the gNB (e.g., gNBl) as shown in Figure 6, that served the UE before the UE loses connection the any gNB. More specifically, as illustrated in Figure 6, the UE is served by a first gNB (gNBl) (step 600). The gNBl and the CN operate to provide the store- and-forward service where a UE context of the UE is transferred to the gateway or CN (step 602). Before the UE loses connection to the serving gNBl, the gateway / CN sends, to a second gNB (gNB2) a CN initiated context setup request including ten UE context information of the UE obtained from the serving gNBl (step 604). The gNB2 sends a response to the gateway / CN such that the NG-U user plane is setup (step 606). Downlink data for the UE is transmitted to and stored in the gNB2 (step 606).

[0098] In one embodiment, the CN may indicate to the gNB (e.g., gNB2) which stores the data packet associated with a store-and-forward service to discard / or withdraw the early “stored” data. Alternatively or additionally, the “stored” data is discarded according to a specified / signaled validity indication or a specified validity timer / counter.

[0099] In one embodiment, a gNB (e.g., gNB2) may handle the at least one data packet associated with a store-and-forward service and the postponed transmission of the at least one data packet associated with a store-and-forward service, as requested by the CN (e.g., AMF, SMF etc., by a gateway on ground). This handling may include acquiring assistance information of the store- and-forward service from the CN.

[0100] In one embodiment, the gNB (e.g., gNB2) signals the UE, by paging or other signaling, an indication that the data packet associated with the store-and-forward service is ready to be provided, after the gNB (e.g., gNB2) moves to the coverage of the UE as determined by the prior knowledge of the gNB (e.g., gNB2) and UE positions and the estimated time period of transmitting the data packet for the UE from the gNB (e.g., gNB2) involved in the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2. Additionally, the indication may by extension indicate that the data to be transmitted is associated with the store-and-forward service.

[0101] In an additional embodiment, if the gNB (e.g., gNB2) cannot find the UE (e.g., if the UE is not within the coverage of the gNB (e.g., gNB2), e.g., within a certain (e.g., specified or predefined or preconfigured) amount of time), the gNB (e.g., gNB2) may notify the CN of thefailure of store-and-forward service to the UE, and the gNB(e.g., gNB2) may then discard the stored data for the store-and-forward service.

[0102] In one embodiment, a gNB (e.g., gNBl, it may be a different gNB from the gNB (e.g., gNB2) providing store-and-forward service) signals the UE before or at the least when RRC is released or the UE moves to RRC INACTIVE e.g. before losing or during loss of gNB coverage that the UE will resume to the cell when it is again with coverage of the cell. Furthermore, the gNB provides the UE at the least one of following information:• The identity of the gNB (e.g., gNB2) that provides the store-and-forward service to the UE, e.g., cell ID, satellite ID.• The estimated time period of transmitting the data packet for the UE from the gNB (e.g., gNB2) that provides the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2.• The non-coverage time period to a UE from the gNB (e.g., gNB2) or any gNB, e.g., which may be started from T0_l to T0_2.

[0103] In one embodiment, a gNB (e.g., gNBl, it may be a different gNB from the gNB (e.g., gNB2) providing store-and-forward service) signals the CN of the valid UE context information.

[0104] In one embodiment, the gNB (e.g., gNB2) sends a signaling to neighbor gNBs (on board different satellites) asking whether one or multiple UEs have been visiting / camping on these neighbor satellites. The gNB(e.g., gNB2) has stored data (received from the CN / gateway on ground) targeting these UEs. After receiving response for at least one neighbor satellite / gNB indicating that at least one target UE has been visiting / camping on this neighbor satellite / gNB, the gNB(e.g., gNB2) sends stored data to this neighbor satellite / gNB via inter-satellite / inter-gNB interface. Prior to sending stored data, the gNB (e.g., gNB2) may also send a signaling to this neighbor gNB checking whether this neighbor gNB agrees to receive stored data for one or multiple target UEs. For a neighbor satellite / gNB which has no connect! on / inter-satellite connection to the gNB, the gNB (e.g., gNB2) may involve the CN (e.g., AMF, SMF, etc.) to setup a connection to the neighbor satellite / gNB.

[0105] In one embodiment, a UE may be aware of a store-and-forward service as indicated by the CN before a store-and-forward service is initiated by the CN, which may include acquiring assistance information of the store-and-forward service from the CN and / or the gNB( e.g., gNB2). This assistance information may include any one or more of the following:• The identity of the gNB providing the store-and-forward service to the UE , e.g., cell ID, satellite ID.• The estimated time period of transmitting the data packet for the UE from the gNB providing the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2.• The non-coverage time period to a UE from the gNB or any gNB, e.g., which may be started from T0_l to T0_2, to UE it is a discontinuous coverage.

[0106] In one embodiment, before the CN provides a data packet for the UE associated with the store-and-forward service to the network node, and before the UE loses the connection to gNB2 or any gNB, to enable store-and-forward service, the UE receives an indication from the CN through one gNB (e.g., gNB 1, which may be a different gNB from the gNB (e.g., gNB2) providing store-and-forward service) that the data packet associated with store-and-forward service will be arriving at the UE after the UE resumes the connection to the gNB (e.g., gNB2), otherwise, the UE may reject receiving the data packet.

[0107] In one embodiment, the UE signals a gNB (e.g., gNBl, which may be a different gNB from the gNB providing store-and-forward service) of the valid UE context information per request from the CN.

[0108] In one embodiment, after acquiring the indication of the store-and-forward service, in order to enable receiving a data packet(s) associated with the store-and-forward service from the gNB (e.g., gNB2) once the gNB connects or resumes connection to the UE, the UE maintains a certain state (e.g., RRC state, for example, the UE remains in RRC CONNECTED or RRC INACTIVE under which the UE can receive data from the gNB) until completing reception of the data packet(s) associated with store-and-forward service.

[0109] In one embodiment, the UE may initiate a request to the gNB (e.g., gNB2) to request the stored data packet associated with the store-and-forward service by the gNB(e.g., gNB2) by Random Access Channel (RACH) or other signaling, after the gNB (e.g., gNB2) moves to the coverage of the UE with respect to the prior knowledge of the gNB (e.g., gNB2) and the UE positions and the estimated time period of transmitting the data packet for the UE from the gNB (e.g., gNB2) involved in the store-and-forward service to the UE, e.g., which may be started from Ti l to Tl_2.

[0110] In an additional embodiment, if the UE camps on and connect to another gNB (e.g., gNB3), i.e., not the gNB (e.g., gNB2) which is provided by the CN, then the UE may request the CN to resend the data packet associated with the store-and-forward service from the CN or from gNB2 by Inter-Satellite Link (ISL) if applicable. After that the CN may indicate gNB2 to discard the stored data for the store-and-forward service.

[0111] In one embodiment, in case of available inter-satellite link between at the least two satellites (serving as two gNBs), to support the store-and-forward service in inter-satellite link, the first gNB may signal a message indicating / requesting store-and-forward service to the second gNB. The second gNB which receives the message may feedback the message, e.g. reject it if the second gNB does not support / want store-and-forward service regarding the request, or accept it and enable the store-and-forward service.

[0112] If more than one gNB both support / enable store-and-forward service and have intersatellite link, then at the least one of gNBs may stores the data packet for a UE, and those gNBs shall all apply the solutions in above embodiments.

[0113] At the end, if one of multiple gNBs completes forwarding the data packet associated with the store-and-forward service to the UE, the gNB m notify the CN or other gNBs (by ISL or by CN) of the completion, and in turn the CN or other gNBs may discard / clear the corresponding data packet.

[0114] Figure 7 illustrates a DL store-and-forward procedure in accordance with one example embodiment of the present disclosure. Note that details regarding the steps of Figure 7 are provided above and those details are equally applicable here to Figure 7. Also note that some of the steps can be optional or come in different order. The steps of the procedure of Figure 7 are as follows:

[0115] Step 700: A serving gNB (e.g., gNBl, which may be a gNB other than the gNB which is involved in the store-and-forward service) of a UE sends UE assistance information (including UE context) to the CN (e.g., to a CN node, e.g., via a gateway).

[0116] Steps 702 A and 702B: The CN node sends, to a gNB (e.g., gNB2), a request for assistance information (e.g., assistance information related to the store-and-forward service). In addition, the CN node sends, to the UE (e.g., via the gateway and the serving gNB), a request for assistance information (e.g., assistance information related to the store-and-forward service).

[0117] Steps 704 A and 704B: The gNB (e.g., gNB2) sends the assistance information to theCN per request. The UE sends the assistance information to the CN per the request.

[0118] Step 706: The CN sends, to the UE (e.g., via the gateway and the serving gNB), an indication that the UE is to prepare to receive a data packet(s) associated with the store-and- forward service.

[0119] Step 708: The CN determines to send a data packet(s) to the UE via the store-and- forward service.

[0120] Step 710: The CN sends, to the gNB (e.g., gNB2) involved in the store-and-forward service, a request for the store-and-forward service.

[0121] Step 712: The gNB (e.g., gNB2) responds with an acknowledgement that indicates that is able and willing to provide the store-and-forward service.

[0122] Step 714: The CN sends the data packet(s) for the store-and-forward service to the gNB (e.g., gNB2) associated with the store-and-forward service and the information about the UE which is to receive the data packet(s).

[0123] Step 716: The gNB (e.g., gNB2) stores (i.e., buffers) the data packet(s) to be sent to the UE via the store-and-forward service.

[0124] Step 718: At the UE side, sometime after Step 706, the UE does not have a connection to the network but the UE still maintains a certain status (e.g., based on receipt of the indication in Step 706).

[0125] Step 720: The gNB (e.g., gNB2) and the UE connect or resume connection. One option is the gNB (e.g., gNB2) signals the UE by paging or other signaling. Another option is the UE signals the gNB by RACH or other signaling to instruct the gNB (e.g., gNB2) to send the stored data packet(s) for the store-and-forward service to the UE.

[0126] Step 722: The gNB (e.g., gNB2) sends the data packet(s) for the store-and-forward service to the UE.

[0127] Step 724: Complete the store-and-forward operation. For example, after the gNB (e.g., gNB2) completes sending the stored data packet(s) for the store-and-forward service to the UE in Step 722, the gNB (e.g., gNB2) informs the CN that the store-and-forward operation is completed.

[0128] Figure 8 shows an example of a communication system 800 in accordance with some embodiments. Note that the network nodes 810 illustrated in Figure 8 may be, for example, NTN nodes described above (e.g., gNBl and gNB2) and, as such, operate in accordance with any of the embodiments described above. In addition, the CN node 808 of Figure 8 may be the CN node described above and, as such, operate in accordance with any of the embodiments described above.

[0129] In the example, the communication system 800 includes a telecommunication network 802 that includes an access network 804, such as a Radio Access Network (RAN), and a core network 806, which includes one or more core network nodes 808. The access network 804 includes one or more access network nodes, such as network nodes 810A and 810B (one or more of which may be generally referred to as network nodes 810), or any other similar Third Generation Partnership Project (3GPP) access nodes or non-3GPP Access Points (APs). Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunicationnetwork 802 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 802 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 802, including one or more network nodes 810 and / or core network nodes 808.

[0130] Examples of an ORAN network node include an Open Radio Unit (O-RU), an Open Distributed Unit (O-DU), an Open Central Unit (O-CU), including an O-CU Control Plane (O- CU-CP) or an O-CU User Plane (O-CU-UP), a RAN intelligent controller (near-real time or non- real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O-RAN Alliance or comparable technologies. The network nodes 810 facilitate direct or indirect connection of User Equipment (UE), such as by connecting UEs 812A, 812B, 812C, and 812D (one or more of which may be generally referred to as UEs 812) to the core network 806 over one or more wireless connections.

[0131] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 800 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0132] The UEs 812 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with thenetwork nodes 810 and other communication devices. Similarly, the network nodes 810 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 812 and / or with other network nodes or equipment in the telecommunication network 802 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 802.

[0133] In the depicted example, the core network 806 connects the network nodes 810 to one or more hosts, such as host 816. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 806 includes one more core network nodes (e.g., core network node 808) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 808. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-Concealing Function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0134] The host 816 may be under the ownership or control of a service provider other than an operator or provider of the access network 804 and / or the telecommunication network 802, and may be operated by the service provider or on behalf of the service provider. The host 816 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0135] As a whole, the communication system 800 of Figure 8 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system 800 may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable Second, Third, Fourth, or Fifth Generation (2G, 3G, 4G, or 5G) standards, or any applicable future generation standard (e.g., Sixth Generation (6G)); Wireless Local Area Network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards(WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any Low Power Wide Area Network (LPWAN) standards such as LoRa and Sigfox.

[0136] In some examples, the telecommunication network 802 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunication network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunication network 802 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing enhanced Mobile Broadband (eMBB) services to other UEs, and / or massive Machine Type Communication (mMTC) / massive Internet of Things (loT) services to yet further UEs.

[0137] In some examples, the UEs 812 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 804. Additionally, a UE may be configured for operating in single- or multi -Radio Access Technology (RAT) or multi -standard mode. For example, a UE may operate with any one or combination of WiFi, New Radio (NR), and LTE, i.e. being configured for Multi -Radio Dual Connectivity (MR-DC), such as Evolved UMTS Terrestrial RAN (E-UTRAN) NR - Dual Connectivity (EN-DC).

[0138] In the example, a hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs (e.g., UE 812C and / or 812D) and network nodes (e.g., network node 810B). In some examples, the hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 814 may be a broadband router enabling access to the core network 806 for the UEs. As another example, the hub 814 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 810, or by executable code, script, process, or other instructions in the hub 814. As another example, the hub 814 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 814 may be a content source. For example, for a UE that is a Virtual Reality (VR) headset, display, loudspeaker or other media delivery device, the hub 814 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 814 then provides to the UE either directly, after performing local processing, and / orafter adding additional local content. In still another example, the hub 814 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0139] The hub 814 may have a constant / persistent or intermittent connection to the network node 810B. The hub 814 may also allow for a different communication scheme and / or schedule between the hub 814 and UEs (e.g., UE 812C and / or 812D), and between the hub 814 and the core network 806. In other examples, the hub 814 is connected to the core network 806 and / or one or more UEs via a wired connection. Moreover, the hub 814 may be configured to connect to a Machine-to-Machine (M2M) service provider over the access network 804 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 810 while still connected via the hub 814 via a wired or wireless connection. In some embodiments, the hub 814 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 810B. In other embodiments, the hub 814 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and the network node 810B, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0140] Figure 9 shows a UE 900 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged, and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, Voice over Internet Protocol (VoIP) phone, wireless local loop phone, desktop computer, Personal Digital Assistant (PDA), wireless camera, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, Laptop Embedded Equipment (LEE), Laptop Mounted Equipment (LME), smart device, wireless Customer Premise Equipment (CPE), vehicle, vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3 GPP, including a Narrowband Internet of Things (NB-IoT) UE, a Machine Type Communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0141] A UE may support Device-to-Device (D2D) communication, for example by implementing a 3 GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), Vehi cl e-to- Vehicle (V2V), Vehicle-to-Infrastructure (V2I), or Vehicle- to-Everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller).Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0142] The UE 900 includes processing circuitry 902 that is operatively coupled via a bus 904 to an input / output interface 906, a power source 908, memory 910, a communication interface 912, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0143] The processing circuitry 902 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 910. The processing circuitry 902 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 902 may include multiple Central Processing Units (CPUs).

[0144] In the example, the input / output interface 906 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 900. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0145] In some embodiments, the power source 908 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 908 may further include powercircuitry for delivering power from the power source 908 itself, and / or an external power source, to the various parts of the UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.

[0146] The memory 910 may be or be configured to include memory such as Random Access Memory (RAM), Read Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically EPROM (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916. The memory 910 may store, for use by the UE 900, any of a variety of various operating systems or combinations of operating systems.

[0147] The memory 910 may be configured to include a number of physical drive units, such as Redundant Array of Independent Disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, High Density Digital Versatile Disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, Holographic Digital Data Storage (HDDS) optical disc drive, external mini Dual In-line Memory Module (DIMM), Synchronous Dynamic RAM (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a tamper resistant module in the form of a Universal Integrated Circuit Card (UICC) including one or more Subscriber Identity Modules (SIMs), such as a Universal SIM (USIM) and / or Internet Protocol Multimedia Services Identity Module (ISIM), other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as a ‘SIM card.’ The memory 910 may allow the UE 900 to access instructions, application programs, and the like stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system, may be tangibly embodied as or in the memory 910, which may be or comprise a device-readable storage medium.

[0148] The processing circuitry 902 may be configured to communicate with an access network or other network using the communication interface 912. The communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 922. The communication interface 912 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a networknode in an access network). Each transceiver may include a transmitter 918 and / or a receiver 920 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 918 and receiver 920 may be coupled to one or more antennas (e.g., the antenna 922) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0149] In the illustrated embodiment, communication functions of the communication interface 912 may include cellular communication, WiFi communication, LPWAN communication, data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, NFC, location-based communication such as the use of the Global Positioning System (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband CDMA (WCDMA), GSM, LTE, NR, UMTS, WiMax, Ethernet, Transmission Control Protocol / Intemet Protocol (TCP / IP), Synchronous Optical Networking (SONET), Asynchronous Transfer Mode (ATM), Quick User Datagram Protocol Internet Connection (QUIC), Hypertext Transfer Protocol (HTTP), and so forth.

[0150] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 912, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected, an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0151] As another example, a UE comprises an actuator, a motor, or a switch related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0152] A UE, when in the form of an loT device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application, and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a television, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smartspeaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or VR, a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 900 shown in Figure 9.

[0153] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3 GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship, an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0154] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator and handle communication of data for both the speed sensor and the actuators.

[0155] Figure 10 shows a network node 1000 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged, and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment in a telecommunication network. Examples of network nodes include, but are not limited to, APs (e.g., radio APs), Base Stations (BSs) (e.g., radio BSs, Node Bs, evolved Node Bs (eNBs), NR Node Bs (gNBs)), and 0-RAN nodes or components of an 0-RAN node (e.g., O-RU, O-DU, O-CU).

[0156] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node), and / or Remote Radio Units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such RRUs may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a Distributed Antenna System (DAS).

[0157] Other examples of network nodes include multiple Transmission Point (multi-TRP) 5G access nodes, Multi -Standard Radio (MSR) equipment such as MSRBSs, network controllers such as Radio Network Controllers (RNCs) or BS Controllers (BSCs), Base Transceiver Stations (BTSs), transmission points, transmission nodes, Multi-Cell / Multicast Coordination Entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0158] The network node 1000 includes processing circuitry 1002, memory 1004, a communication interface 1006, and a power source 1008. The network node 1000 may be composed of multiple physically separate components (e.g., a NodeB component and an RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1000 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair may in some instances be considered a single separate network node. In some embodiments, the network node 1000 may be configured to support multiple RATs. In such embodiments, some components may be duplicated (e.g., separate memory 1004 for different RATs) and some components may be reused (e.g., a same antenna 1010 may be shared by different RATs). The network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, Long Range Wide Area Network (LoRaWAN), Radio Frequency Identification (RFID), or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within the network node 1000.

[0159] The processing circuitry 1002 may comprise a combination of one or more of a microprocessor, controller, microcontroller, CPU, DSP, ASIC, FPGA, or any other suitable computing device, resource, or combination of hardware, software, and / or encoded logic operable to provide, either alone or in conjunction with other network node 1000 components, such as the memory 1004, to provide network node 1000 functionality.

[0160] In some embodiments, the processing circuitry 1002 includes a System on a Chip (SOC). In some embodiments, the processing circuitry 1002 includes one or more of Radio Frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014. In some embodiments, the RF transceiver circuitry 1012 and the baseband processing circuitry 1014 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of the RF transceiver circuitry 1012 and the baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.

[0161] The memory 1004 may comprise any form of volatile or non-volatile computer- readable memory including, without limitation, persistent storage, solid state memory, remotely mounted memory, magnetic media, optical media, RAM, ROM, mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD), or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device- readable, and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1002. The memory 1004 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1002 and utilized by the network node 1000. The memory 1004 may be used to store any calculations made by the processing circuitry 1002 and / or any data received via the communication interface 1006. In some embodiments, the processing circuitry 1002 and the memory 1004 are integrated.

[0162] The communication interface 1006 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1006 comprises port(s) / terminal(s) 1016 to send and receive data, for example to and from a network over a wired connection. The communication interface 1006 also includes radio front-end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. The radio front-end circuitry 1018 comprises filters 1020 and amplifiers 1022. The radio front-end circuitry 1018 may be connected to the antenna 1010 and the processing circuitry 1002. The radio front-end circuitry 1018 may be configured to condition signals communicated between the antenna 1010 and the processing circuitry 1002. The radio front-endcircuitry 1018 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of the filters 1020 and / or the amplifiers 1022. The radio signal may then be transmitted via the antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1018. The digital data may be passed to the processing circuitry 1002. In other embodiments, the communication interface 1006 may comprise different components and / or different combinations of components.

[0163] In certain alternative embodiments, the network node 1000 does not include separate radio front-end circuitry 1018; instead, the processing circuitry 1002 includes radio front-end circuitry and is connected to the antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of the communication interface 1006. In still other embodiments, the communication interface 1006 includes the one or more ports or terminals 1016, the radio front-end circuitry 1018, and the RF transceiver circuitry 1012 as part of a radio unit (not shown), and the communication interface 1006 communicates with the baseband processing circuitry 1014, which is part of a digital unit (not shown).

[0164] The antenna 1010 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1010 may be coupled to the radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1010 is separate from the network node 1000 and connectable to the network node 1000 through an interface or port.

[0165] The antenna 1010, the communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node 1000. Any information, data, and / or signals may be received from a UE, another network node, and / or any other network equipment. Similarly, the antenna 1010, the communication interface 1006, and / or the processing circuitry 1002 may be configured to perform any transmitting operations described herein as being performed by the network node 1000. Any information, data, and / or signals may be transmitted to a UE, another network node, and / or any other network equipment.

[0166] The power source 1008 provides power to the various components of the network node 1000 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1000 with power for performing the functionality described herein. For example, the network node 1000 may beconnectable to an external power source (e.g., the power grid or an electricity outlet) via input circuitry or an interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1008. As a further example, the power source 1008 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0167] Embodiments of the network node 1000 may include additional components beyond those shown in Figure 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1000 may include user interface equipment to allow input of information into the network node 1000 and to allow output of information from the network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1000. In some embodiments providing a core network node, such as core network node 108 of FIG. 8, some components, such as the radio front-end circuitry 1018 and the RF transceiver circuitry 1012 may be omitted.

[0168] Figure 11 is a block diagram illustrating a virtualization environment 1100 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices, and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more Virtual Machines (VMs) implemented in one or more virtualization environments 1100 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, a UE, a core network node, or a host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1100 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an O-2 interface. Virtualization may facilitate distributed implementations of a network node, a UE, a core network node, or a host.

[0169] Applications 1102 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in thevirtualization environment 1100 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0170] Hardware 1104 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, an input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1106 (also referred to as hypervisors or Virtual Machine Monitors (VMMs)), provide VMs 1108 A and 1108B (one or more of which may be generally referred to as VMs 1108), and / or perform any of the functions, features, and / or benefits described in relation with some embodiments described herein. The virtualization layer 1106 may present a virtual operating platform that appears like networking hardware to the VMs 1108.

[0171] The VMs 1108 comprise virtual processing, virtual memory, virtual networking, or interface and virtual storage, and may be run by a corresponding virtualization layer 1106. Different embodiments of the instance of a virtual appliance 1102 may be implemented on one or more of VMs 1108, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as Network Function Virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers and customer premise equipment.

[0172] In the context of NFV, a VM 1108 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1108, and that part of the hardware 1104 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1108 on top of the hardware 1104 and corresponds to the application 1102.

[0173] The hardware 1104 may be implemented in a standalone network node with generic or specific components. The hardware 1104 may implement some functions via virtualization. Alternatively, the hardware 1104 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1110, which, among others, oversees lifecycle management of the applications 1102. In some embodiments, the hardware 1104 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriatenetwork interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1112 which may alternatively be used for communication between hardware nodes and radio units.

[0174] Although the computing devices described herein (e.g., UEs, network nodes) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions, and methods disclosed herein. Determining, calculating, obtaining, or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

[0175] In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer- readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.

[0176] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

[0177] Some exemplary embodiments of the present disclosure are as follows:Group A Embodiments

[0178] Embodiment 1 : A method performed by a User Equipment, UE, for reception of data via a store-and-forward service of a wireless communications system (e.g., a cellular communications system), the method comprising: receiving (706) an indication of a store-and- forward service; based on the received indication, maintaining (718) a certain status (e.g., a certain RRC status) while a network connection is unavailable; receiving (722), from a network node, one or more data packets for the store-and-forward service upon or during connection or resuming a connection with the network node.

[0179] Embodiment 2: The method of embodiment 1, wherein the certain status is a certain Radio Resource Control, RRC, status.

[0180] Embodiment 3: The method of embodiment 1 or 2, wherein the certain status is a connected state (e.g., RRC connected) or an inactive state (RRC inactive).

[0181] Embodiment 4: The method of any of embodiments 1 to 3, wherein receiving (706) the indication of the store-and-forward service comprises receiving (706) the indication of the store- and-forward service from a core network node (e.g., AMF or SMF) in a core network of the wireless communications system via a serving network node (e.g., a serving base station).

[0182] Embodiment 5: The method of embodiment 4, wherein the serving network node is a Non-Terrestrial Network (NTN) node.

[0183] Embodiment 6: The method of embodiment 4 or 5, wherein the network node from which the UE receives the one or more data packets for the store-and-forward service is the serving network node from which the UE received the indication of the store-and-forward service.

[0184] Embodiment 7: The method of embodiment 4 or 5, wherein the network node from which the UE receives the one or more data packets for the store-and-forward service is a network node other than the serving network node from which the UE received the indication of the store- and-forward service.

[0185] Embodiment 8: The method of any of embodiments 1 to 7, further comprising, prior to receiving (722) the one or more data packets for the store-and-forward service, connecting or resuming a connection with the network node in response to reception of a paging or other signaling from the network node.

[0186] Embodiment 9: The method of any of embodiments 1 to 7, further comprising, prior to receiving (722) the one or more data packets for the store-and-forward service, sending an indication or request (e.g., via RACH or otherwise) to the network node to send the one or more data packets for the store-and-forward service.

[0187] Embodiment 10: The method of any of embodiments 1 to 9, wherein receiving (706) the indication of the store-and-forward service comprises receiving assistance information for the store-and-forward service.

[0188] Embodiment 11 : The method of embodiment 10, wherein the assistance information for the store-and-forward service comprises any one or more of the following: an identity (e.g., cell ID, satellite ID, or the like) of the network node providing the store-and-forward service to the UE; information that indicates a time period during which the one or more data packets for the store-and-forward service will be sent from the network node to the UE; information that indicates a time period during which the UE will be out of network coverage.

[0189] Embodiment 12: The method of any of embodiments 1 to 11, further comprising sending (704B), to the core network node, assistance information for the store-and-forward service.

[0190] Embodiment 13: The method of embodiment 12, wherein the assistance information for the store-and-forward service sent from the UE to the core network node comprises any one or more of the following: an indicator indicating that the UE supports the store-and-forward service; an indicator indicating that the UE enables the store-and-forward service; an identity of the UE (e g., UE ID); an identity of a UE context of the UE (e g., RAN UE NGAP ID, AMF UE NGAP ID); a position of the UE (e.g., geographic area or Tracking Area Code, TAC); a time period for transmitting the one or more data packets for the UE from the network node involved in the store- and-forward service to the UE; a UE context of the UE (e.g., UE RRC context, e.g. the PDU sessions, the QoS flow to DRB mapping, UE capability, UE history information, and / or the like).

[0191] Embodiment 14: The method of any of embodiments 1 to 13, wherein the network node from which the UE receives the one or more data packets for the store-and-forward service is a Non-Terrestrial Network (NTN) node.Group B Embodiments

[0192] Embodiment 15: A method performed by a network node (e.g., gNBl) for a wireless communications system for a downlink store-and-forward service, the method comprising: sending (700), to a core network node in a core network of the wireless communications system,User Equipment, UE, assistance information for a store-and-forward service for downlink data packet(s) for the UE.

[0193] Embodiment 16: The method of embodiment 15, wherein the UE assistance information comprises a UE context of the UE.

[0194] Embodiment 17: A method performed by a network node (e.g., gNB2) for a wireless communications system for a downlink store-and-forward service, the method comprising: receiving (714), from a core network node in a core network of the wireless communications system, one or more data packets for a User Equipment, UE, to be sent to the UE via a store-and- forward service; storing (716) the one or more data packets; transmitting (722), to the UE, the one or more data packets stored for the UE for the store-and-forward service upon or during the UE connecting to the network node or resuming a connection with the network node.

[0195] Embodiment 18: The method of embodiment 17, further comprising, prior to transmitting (722) the one or more data packets for the store-and-forward service to the UE, transmitting a paging message or other signaling message to the UE (e.g., that indicates the presence of the stored one or more data packets for the UE for the store-and-forward service).

[0196] Embodiment 19: The method of embodiment 17, further comprising, prior to transmitting (722) the one or more data packets for the store-and-forward service to the UE, receiving, from the UE, an indication or request (e.g., via RACH or otherwise) to send the one or more data packets for the store-and-forward service.

[0197] Embodiment 20: The method of any of embodiments 17 to 19, further comprising sending (704A), to the core network node, assistance information for the store-and-forward service.

[0198] Embodiment 21 : The method of embodiment 20, wherein the assistance information for the store-and-forward service sent from the network node to the core network node comprises any one or more of the following: an indicator indicating that the network node supports the store- and-forward service; an indicator indicating that the network node enables the store-and-forward service; ephemeris data of a satellite associated to the network node (e.g., a satellite that corresponds to or carries the network node); an identity of the network node (e.g., Cell ID or Satellite ID); a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE; a non-coverage time period (e.g. T0_l to T0_2).

[0199] Embodiment 22: The method of any of embodiments 17 to 21, wherein the network node is a Non-Terrestrial Network (NTN) node.Group C Embodiments

[0200] Embodiment 23: A method performed by a core network node (e.g., AMF or SMF) for a wireless communications system for a downlink store-and-forward service, the method comprising any one or more of the following: sending (706), to a User Equipment, UE, (e.g., via a network node, e.g., gNB), an indication of a store-and-forward service; determining (708) that the store-and-forward service is desired for one or more downlink data packets for the UE; sending (714) the one or more data packets for the UE to a network node (e.g., gNB2) that provides the store-and-forward service.

[0201] Embodiment 24: The method of embodiment 23, the indication for the store-and- forward service explicitly or implicitly indicates that the UE is to maintain a certain status when a network connection is unavailable.

[0202] Embodiment 25: The method of embodiment 24, wherein the certain status is a certain Radio Resource Control, RRC, status.

[0203] Embodiment 26: The method of embodiment 24 or 25, wherein the certain status is a connected state (e.g., RRC connected) or an inactive state (RRC inactive).

[0204] Embodiment 27: The method of any of embodiments 23 to 26, wherein sending (706) the indication of the store-and-forward service to the UE comprises sending (706) the indication of the store-and-forward service to the UE via a serving network node (e.g., a serving base station) of the UE.

[0205] Embodiment 28: The method of embodiment 27, wherein the serving network node of the UE is a Non-Terrestrial Network (NTN) node.

[0206] Embodiment 29: The method of any of embodiments 23 to 28, wherein sending (706) the indication of the store-and-forward service comprises sending assistance information for the store-and-forward service.

[0207] Embodiment 30: The method of embodiment 29, wherein the assistance information for the store-and-forward service comprises any one or more of the following: an identity (e.g., cell ID, satellite ID, or the like) of the network node providing the store-and-forward service to the UE; information that indicates a time period during which the one or more data packets for the store-and-forward service will be sent from the network node to the UE; information that indicates a time period during which the UE will be out of network coverage.

[0208] Embodiment 31 : The method of any of embodiments 23 to 30, further comprising receiving (704B), from the UE, assistance information for the store-and-forward service.

[0209] Embodiment 32: The method of embodiment 31, wherein the assistance information for the store-and-forward service received from the UE comprises any one or more of thefollowing: an indicator indicating that the UE supports the store-and-forward service; an indicator indicating that the UE enables the store-and-forward service; an identity of the UE (e.g., UE ID); an identity of a UE context of the UE (e.g., RAN UE NGAP ID, AMF UE NGAP ID); a position of the UE (e.g., geographic area or Tracking Area Code, TAC); a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE; a UE context of the UE (e.g., UE RRC context, e.g. the PDU sessions, the QoS flow to DRB mapping, UE capability, UE history information, and / or the like).

[0210] Embodiment 33: The method of any of embodiments 23 to 32, further comprising receiving (704A), from the network node, assistance information for the store-and-forward service.

[0211] Embodiment 34: The method of embodiment 33, wherein the assistance information for the store-and-forward service received from the network node comprises any one or more of the following: an indicator indicating that the network node supports the store-and-forward service; an indicator indicating that the network node enables the store-and-forward service; ephemeris data of a satellite associated to the network node (e.g., a satellite that corresponds to or carries the network node); an identity of the network node (e.g., Cell ID or Satellite ID); a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE; a non-coverage time period (e.g. T0_l to T0_2).

[0212] Embodiment 35: The method of any of embodiments 23 to 34, wherein the network node to which the one or more data packets for the UE for the store-and-forward service is a NonTerrestrial Network (NTN) node.Group D Embodiments

[0213] Embodiment 36: A user equipment comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the processing circuitry.

[0214] Embodiment 37: A network node comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; power supply circuitry configured to supply power to the processing circuitry.

[0215] Embodiment 38: A network node comprising: processing circuitry configured to perform any of the steps of any of the Group C embodiments; power supply circuitry configured to supply power to the processing circuitry.

[0216] Embodiment 39: A user equipment (UE) comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and theprocessing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

Claims

CLAIMS1. A method performed by a User Equipment, UE, for reception of data via a store-and- forward service of a wireless communications system, the method comprising: receiving (706) an indication of a store-and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE and a radio access network, RAN, of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node; based on the received indication, maintaining (718) a certain status while the network connection between the UE and the RAN of the wireless communications system is unavailable; and upon or during connection or resuming a connection with the network node, receiving (722), from the network node, one or more downlink data packets stored by the network node for the store-and-forward service while the network connection between the UE and the RAN of the wireless communication system was unavailable.

2. The method of claim 1, wherein the network node is a Non-Terrestrial Network, NTN, node in the RAN of the wireless communications system.

3. The method of claim 1 or 2, wherein the certain status is a certain Radio Resource Control, RRC, status.

4. The method of any of claims 1 to 3, wherein receiving (706) the indication of the store- and-forward service comprises receiving (706) the indication of the store-and-forward service from a core network node in a core network of the wireless communications system via a serving network node of the UE.

5. The method of claim 4, wherein the network node from which the UE receives the one or more downlink data packets for the store-and-forward service is the serving network node from which the UE received the indication of the store-and-forward service.

6. The method of claim 4, wherein the network node from which the UE receives the one or more downlink data packets for the store-and-forward service is a network node other than the serving network node from which the UE received the indication of the store-and-forward service.

7. The method of any of claims 4 to 6, further comprising sending (704B), to the core network node, assistance information for the store-and-forward service, wherein the assistance information for the store-and-forward service sent from the UE to the core network node comprises any one or more of the following: an indicator indicating that the UE supports the store-and-forward service; an indicator indicating that the UE enables the store-and-forward service; an identity of the UE; an identity of a UE context of the UE; a position of the UE; a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE; a UE context of the UE.

8. The method of any of claims 4 to 7, wherein receiving (706) the indication of the store- and-forward service comprises receiving (706) assistance information for the store-and-forward service, wherein the assistance information for the store-and-forward service comprises any one or more of the following: an identity of the network node providing the store-and-forward service to the UE; information that indicates a time period during which the one or more downlink data packets for the store-and-forward service will be sent from the network node to the UE; information that indicates a time period during which the UE will be out of network coverage.

9. The method of any of claims 1 to 8, further comprising, prior to receiving (722) the one or more data packets for the store-and-forward service, sending (720) an indication or request to the network node to send the one or more data packets for the store-and-forward service.

10. A User Equipment, UE, for reception of data via a store-and-forward service of a wireless communications system, the UE adapted to: receive (706) an indication of a store-and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a radio access network, RAN, of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming thenetwork connection with the network node; based on the received indication, maintain (718) a certain status while the network connection between the UE and the RAN of the wireless communications system is unavailable; and upon or during connection or resuming a connection with the network node, receive (722), from a network node, one or more downlink data packets stored by the network node for the store- and-forward service while the network connection between the UE and the RAN of the wireless communication system was unavailable.

11. The UE of claim 10, further adapted to perform the method of any of claims 2 to 9.

12. A User Equipment, UE, (900) for reception of data via a store-and-forward service of a wireless communications system, the UE comprising: a communication interface (912) comprising a transmitter (918) and a receiver (920); and processing circuitry (902) associated with the communication interface (912), the processing circuitry (902) configured to cause the UE (900) to: receive (706) an indication of a store-and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a radio access network, RAN, of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node; based on the received indication, maintain (718) a certain status while the network connection between the UE and the RAN of the wireless communications system is unavailable; and upon or during connection or resuming a connection with the network node, receive (722), from a network node, one or more downlink data packets stored by the network node for the store-and-forward service while the network connection between the UE and the RAN of the wireless communication system was unavailable.

13. The UE of claim 12, wherein the processing circuitry (902) is further configured to cause the UE (900) to perform the method of any of claims 2 to 9.

14. A method performed by a network node for a wireless communications system for a downlink store-and-forward service, the method comprising:receiving (714), from a core network node in a core network of the wireless communications system, one or more downlink data packets for a User Equipment, UE, to be sent to the UE via a store-and-forward service; storing (716) the one or more downlink data packets; transmitting (722), to the UE, the one or more data packets stored for the UE for the store- and-forward service upon or during the UE connecting to the network node or resuming a connection with the network node.

15. The method of claim 14, further comprising, prior to transmitting (722) the one or more data packets for the store-and-forward service to the UE, transmitting (720) a paging message or other signaling message to the UE that indicates the presence of the stored one or more data packets for the UE for the store-and-forward service.

16. The method of claim 14, further comprising, prior to transmitting (722) the one or more data packets for the store-and-forward service to the UE, receiving (720), from the UE, an indication or request to send the one or more data packets for the store-and-forward service.

17. The method of any of claims 14 to 16, further comprising sending (704A), to the core network node, assistance information for the store-and-forward service, wherein the assistance information for the store-and-forward service sent from the network node to the core network node comprises any one or more of the following: an indicator indicating that the network node supports the store-and-forward service; an indicator indicating that the network node enables the store-and-forward service; ephemeris data of a satellite associated to the network node; an identity of the network node; a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE; a non-coverage time period.

18. The method of any of claims 14 to 17, wherein the network node is a Non-Terrestrial Network, NTN, node.

19. A network node for a wireless communications system for a downlink store-and-forward service, the network node adapted to:receive (714), from a core network node in a core network of the wireless communications system, one or more downlink data packets for a User Equipment, UE, to be sent to the UE via a store-and-forward service; store (716) the one or more downlink data packets; transmit (722), to the UE, the one or more data packets stored for the UE for the store-and- forward service upon or during the UE connecting to the network node or resuming a connection with the network node.

20. The network node of claim 19, further adapted to perform the method of any of claims 15 to 18.

21. A network node (1000) for a wireless communications system for a downlink store-and- forward service, the network node comprising processing circuitry (1002) configured to cause the network node (1000) to: receive (714), from a core network node in a core network of the wireless communications system, one or more downlink data packets for a User Equipment, UE, to be sent to the UE via a store-and-forward service; store (716) the one or more downlink data packets; transmit (722), to the UE, the one or more data packets stored for the UE for the store-and- forward service upon or during the UE connecting to the network node or resuming a connection with the network node.

22. The network node (1000) of claim 21, wherein the processing circuitry (1002) is further configured to cause the network node (1000) to perform the method of any of claims 15 to 18.

23. A method performed by a core network node or gateway for a wireless communications system for a downlink store-and-forward service, the method comprising: determining (708) to send downlink data packets to a User Equipment, UE, via a store- and-forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a radio access network, RAN, of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node; sending (706), to the UE, an indication of the store-and-forward service before the networkconnection between the UE and RAN is unavailable; and sending (714), to a network node, one or more downlink data packets for UE to be sent to the UE via the store-and-forward service.

24. The method of claim 23, wherein sending (706) the indication of the store-and-forward service to the UE comprises sending (706) the indication of the store-and-forward service to the UE via a serving network node of the UE.

25. The method of claim 24, wherein the serving network node of the UE is a Non-Terrestrial Network, NTN, node.

26. The method of any of claims 23 to 25, wherein the indication of the store-and-forward service sent to the UE comprises any one or more of the following: an identity of the network node providing the store-and-forward service to the UE; information that indicates a time period during which the one or more downlink data packets for the store-and-forward service will be sent from the network node to the UE; information that indicates a time period during which the UE will be out of network coverage.

27. The method of any of claims 23 to 26, wherein the indication of the store-and-forward service sent to the UE explicitly or implicitly indicates that the UE is to maintain a certain status when a network connection is unavailable.

28. The method of any of claims 23 to 27, further comprising, prior to sending (706) the one or more downlink data packets to the network node: sending (710), to the network node, a request for the network node to provide the store- and-forward service for downlink data packets for the UE; and receiving (712), from the second network node, a response that indicates that the network node is willing and able to provide the store-and-forward service for downlink data packets for the UE.

29. The method of any of claims 23 to 28, further comprising receiving (700), from a serving network node of the UE, first assistance information for the store-and-forward service for downlink data packets for the UE.

30. The method of claim 29, wherein the first assistance information comprises a UE context of the UE.

31. The method of any of claims 23 to 30, further comprising obtaining (702A-702B), from the UE, second assistance information for the store-and-forward service for downlink data packets for the UE, wherein the second assistance information for the store-and-forward service obtained from the UE comprises any one or more of the following: an indicator indicating that the UE supports the store-and-forward service; an indicator indicating that the UE enables the store-and-forward service; an identity of the UE; an identity of a UE context of the UE; a position of the UE; a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE; a UE context of the UE.

32. The method of any of claims 23 to 31, further comprising obtaining (704A-704B), from the network node, third assistance information for the store-and-forward service for downlink data packets for the UE, wherein the third assistance information comprises any one or more of the following: an indicator indicating that the network node supports the store-and-forward service; an indicator indicating that the network node enables the store-and-forward service; ephemeris data of a satellite associated to the network node; an identity of the network node; a time period for transmitting the one or more data packets for the UE from the network node involved in the store-and-forward service to the UE; a non-coverage time period.

33. The method of any of claims 29 to 32, wherein the determining (708) is based on the assistance information.

34. A core network node or gateway for a wireless communications system for a downlink store-and-forward service, the core network node or gateway adapted to:determine (708) to send downlink data packets to a User Equipment, UE, via a store-and- forward service via which downlink data packets for the UE will be stored at a network node while a network connection between the UE a radio access network, RAN, of the wireless communications system is unavailable and subsequently forwarded to the UE upon or during establishment of a new network connection or resuming the network connection with the network node; send (706), to the UE, an indication of the store-and-forward service before the network connection between the UE and RAN is unavailable; and send (714), to a network node, one or more downlink data packets for UE to be sent to the UE via the store-and-forward service.

35. The core network node or gateway of claim 34, further adapted to perform the method of any of claims 24 to 33.

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