Method and apparatus for managing data delivery in store and forward mode within satellite communication network

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method for managing data delivery in a store and forward (S&F) mode within a satellite communication network includes detecting, by a ground station, an event associated with a user equipment (UE), determining, by the ground station, feeder link availability information and expected delivery time information based on at least one of availability of a satellite constellation or a time until the next satellite connects to the ground station, and reporting, by the ground station, the feeder link availability information and the expected delivery time information to an application function (AF) apparatus.

Description

METHOD AND APPARATUS FOR MANAGING DATA DELIVERY IN STORE AND FORWARD MODE WITHIN SATELLITE COMMUNICATION NETWORK

[0001] The present application is based on and claims priority from an Indian Provisional Application Number 202441010771 filed on 15th February 2024, the disclosure of which is hereby incorporated by reference herein. The disclosure relates to wireless communication and more particularly relates to a method and system for managing data delivery in store and forward (S&F) mode within satellite communication network.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] In an embodiment of the disclosure, a method for managing data delivery in the S&F mode within the satellite communication network is provided. The method may include detecting by the ground station an event associated with the UE. The satellite communication network may include an MME-onboard on a satellite and the MME-ground on a ground station. The event may include at least one of the UE is registered in the S&F mode in response to the UE registering on a cell that supports the S&F mode in the satellite communication network, a change in previously reported values of Downlink S&F estimated Delivery Time, or a feeder link availability period. The method may include determining by the ground station feeder link availability information and expected delivery time information based on at least one of availability of a satellite constellation or a time until the next satellite connects to the ground station. The method may include reporting by the ground station the feeder link availability information and the expected delivery time information to an application function (AF) apparatus.

[0009] In an embodiment of the disclosure, a method for managing the delivery of data in the S&F mode within the satellite communication network is provided. The method may include receiving by the AF apparatus a notification from the ground station. The notification may comprise an indication comprising at least one of a UE is registered in the S&F mode, a Downlink S&F estimated Delivery Time, feeder link availability information, or a feeder link availability period. The method may include determining by the AF apparatus an expected delivery time required to deliver the data to the UE based on the notification. The method may include transmitting by the AF apparatus the data to the UE based on the expected delivery time.

[0010] In an embodiment of the disclosure, a ground station for managing data delivery in a S&F mode within a satellite communication network is provided. The ground station may include memory, and at least one processor coupled with the memory. The at least one processor may be configured to detect the event associated with the UE. The satellite communication network may comprise an MME-onboard on the satellite and the MME-ground on the ground station. The event may comprise at least one of the UE is registered in the S&F mode in response to the UE registering on a cell that supports the S&F mode in the satellite communication network, a change in previously reported values of Downlink S&F estimated Delivery Time, or a feeder link availability period. The at least one processor may be configured to determine the feeder link availability information and expected delivery time information based on at least one of availability of a satellite constellation or a time until the next satellite connects to the ground station. The at least one processor may be configured to report the feeder link availability information and the expected delivery time information to the AF apparatus.

[0011] In an embodiment of the disclosure, an AF apparatus for managing the delivery of data in the S&F mode within the satellite communication network is provided. The AF apparatus may include memory, and at least one processor coupled with the memory. The at least one processor may be configured to receive a notification from a ground station. The notification may comprise an indication comprising at least one of the UE is registered in the S&F mode, a Downlink S&F estimated Delivery Time, feeder link availability information or a feeder link availability period. The at least one processor may be configured to determine an expected delivery time required to deliver data to the UE based on the notification. The at least one processor may be configured to transmit the data to the UE based on the expected delivery time.

[0012] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It is understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

[0013] These and other features, aspects, and advantages of the present embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0014] Fig. 1 is a block diagram that illustrates the hardware components associated with the ground station according to an embodiment of the disclosure.

[0015] Fig. 2 is a block diagram that illustrates the hardware components associated with the AF apparatus according to an embodiment of the disclosure.

[0016] Fig. 3 is a sequence diagram that illustrates the indication of the S&F event information to the AF apparatus by the ground station according to an embodiment of the disclosure.

[0017] Fig. 4 is a flow diagram that illustrates the method of transmitting the occurrence of the event estimated data delivery time along with the feeder link availability information according to an embodiment of the disclosure.

[0018] Fig. 5 is a flow diagram that illustrates the method of transmission of the downlink data from the AF apparatus to the UE based on the expected delivery time according to an embodiment of the disclosure.

[0019] Fig. 6 illustrates a entity in a wireless communication system according to an embodiment of the disclosure.

[0020] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and details in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0021] The term "or" as used herein, refers to a non-exclusive or, unless otherwise indicated. Throughout the disclosure, the expression "at least one of a, b or c" indicates only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples are not be construed as limiting the scope of the embodiments herein.

[0022] As is traditional in the field, embodiments are described and illustrated in terms of blocks that carry out a described function or functions.　These blocks, which referred to herein as managers, units, modules, hardware components or the like, are physically implemented by analog and / or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and optionally be driven by firmware and software. The circuits, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like.　The circuits constituting a block be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments be physically separated into two or more interacting and discrete blocks without departing from the scope of the proposed method.　Likewise, the blocks of the embodiments be physically combined into more complex blocks without departing from the scope of the proposed method.

[0023] The accompanying drawings are used to help easily understand various technical features and it is understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the proposed method is construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. used herein to describe various elements, these elements are not be limited by these terms. These terms are generally used to distinguish one element from another.

[0024] The Store and Forward (S&F) Satellite Operation is a critical mode of communication within the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) that utilizes satellite access. This mode is particularly suitable for delay-tolerant communication services, such as Cellular Internet of Things (CIoT) and Machine Type Communications (MTC) Short Message Service (SMS). In scenarios where the satellite does not support the S&F operation mode and lacks a feeder link connection to the ground network, the satellite is unable to provide any service to User Equipment (UE). Conversely, when both the service link and feeder link are available, all services can be provided seamlessly.

[0025] To support the S&F Satellite operation, specific network functionalities need to be deployed on the satellite. In the S&F mode, the end-to-end exchange of signaling and data traffic is managed through a sequence of steps that reflect the intermittent availability of the service link, allowing the satellite to exchange data with the UE, and the intermittent availability of the ground link, enabling data exchange between the satellite and the core network. When operating in S&F mode, the satellite's on-board network broadcasts an indication of this mode, which the UE uses to determine the satellite's current operational status. If the satellite is in S&F mode and the UE is enabled for such operation, the UE indicates its S&F capability during the Attach and Tracking Area Update processes.

[0026] The S&F Satellite operation mode facilitates communication services by storing and forwarding information to the UE during periods or in geographical areas where the serving satellite is not simultaneously connected to the ground network via a feeder link or Inter-Satellite Links (ISL). In the context of uploading (UL), "store" refers to the on-board storage of UL information from the UE, and "forward" pertains to the forwarding of this stored UL information to the ground network. For downloading (DL), "store" involves the on-board storage of DL information from the ground network, and "forward" denotes the forwarding of this stored DL information to the UE.

[0027] During the S&F Satellite operation, an Application Function (AF) that receives S&F event information from a Core Network (CN) can significantly enhance service delivery concerning aspects such as Quality of Service (QoS), data size, and scheduling. However, a significant challenge currently exists in that there is no system or method available to indicate the estimated time of data delivery to the AF. This limitation hampers the ability to optimize service delivery and manage user expectations effectively.

[0028] Thus, it is desired to address the above-mentioned disadvantages, issues or other shortcomings or at least provide a useful alternative.

[0029] The principal object of the disclosure herein is to provide a system and method for managing data delivery in the S&F mode within the satellite communication network.

[0030] An object of the disclosure herein is to indicate the estimated data delivery time to the AF to enhance service delivery with respect to aspects such as QoS, data size, and scheduling.

[0031] An object of the disclosure is related to detecting an event that UE is registered in S&F mode in response to the UE registering on the cell which is supporting S&F mode.

[0032] An object of the disclosure is to provide a system that determines the feeder link availability information and expected delivery time information depending on the satellite constellation and the time the next satellite will connect to the MME.

[0033] The present disclosure relates to monitoring events in satellite communication, specifically within a 3GPP system, and making such monitoring event information available via a Service Capability Exposure Function (SCEF). The disclosure comprises means that allow the identification of the 3GPP network element suitable for configuring specific events, detecting these events, and reporting them to authorized users, such as applications or logging systems. Upon detection of such an event, the network may be configured to perform special actions, such as limiting the UE access.

[0034] This disclosure provides a system for monitoring and reporting various events within a 3GPP network, enhancing the ability to manage and respond to specific conditions effectively. Supported monitoring events include the association of the UE and Universal Integrated Circuit Card (UICC) and / or new International Mobile Subscriber Identity-International Mobile Equipment Identity-Software Version (IMSI-IMEI-SV) association. The system determines UE reachability and tracks the location of the UE, including changes in its location. Loss of connectivity is detected, and communication failures are identified.

[0035] The roaming status of the UE, whether it is in the Home Public Land Mobile Network (HPLMN) or Visited Public Land Mobile Network (VPLMN), is monitored, with changes in the roaming status based on the most recently received registration state in the Home Subscriber Server (HSS). The number of UEs present in a geographical area is counted, ensuring availability after Data Distribution Network (DDN) failure. Additionally, Packet Data Network (PDN) connectivity status is monitored.

[0036] Monitoring Duration is an optional parameter that indicates the absolute time at which the related monitoring event request is considered to expire. For Monitoring Requests for a group, this parameter applies to every group member UE. The inclusion of either Maximum Number of Reports (with a value higher than one) or Monitoring Duration makes the Monitoring Request a Continuous Monitoring Request. A single Monitoring Request may generate more than one Monitoring Indication message for a Continuous Monitoring Request.

[0037] Specific parameters for the monitoring event include loss of connectivity, UE reachability, location reporting, Change of IMSI-IMEI(SV) Association, Roaming Status, Communication failure, Availability after DDN Failure, PDN Connectivity Status, Store and Forward, Satellite operation information, and others.

[0038] The Loss of connectivity indicates when the 3GPP network detects that the UE is no longer reachable for either signaling or user plane communication. Such a condition is identified when the mobile reachability timer expires in the network, when the UE detaches, and when an active UE is purged. The SCS / AS may provide a Maximum Detection Time, which indicates the maximum period of time without any communication with the UE, after which the SCS / AS is to be informed that the UE is considered to be unreachable.

[0039] Location reporting monitoring events allow the SCS / AS to request either the Current Location or the Last Known Location of the UE. The supported accuracy in the network may be at different levels. Only one-time reporting is supported for the Last Known Location. One-time and continuous location reporting are supported for the Current Location. For continuous location reporting, unless a minimum reporting interval was provided, the serving node(s) sends a notification every time it becomes aware of a location change. The granularity depends on the accepted accuracy. The minimum reporting interval is an optional parameter that indicates a minimum time interval between location reporting notifications. Further, the roaming status allows the SCS / AS to query the UE's current roaming status (the serving PLMN and / or whether the UE is in its HPLMN) and to get notified when that status changes.

[0040] The UE location information may include a timestamp to indicate when the UE was last known to be in that location, i.e., if the current location or the last-known location is provided. The network may use satellite coverage availability information to support satellite access by UEs with discontinuous coverage operation. The satellite coverage availability information provisioned to the network by the UE or the satellite coverage availability information determined by the network describes when and where the satellite coverage with both service link and feeder link connectivity is expected or not expected to be available in an area.

[0041] The S&F is an operation mode of a 5G system with satellite access where the 5G system can provide some level of service (in storing and forwarding the data) when satellite connectivity is intermittently / temporarily unavailable, e.g., to provide communication service for UEs under satellite coverage without a simultaneous active feeder link connection to the ground station. In the S&F mode, the link between the UE and satellite (service link) and between the satellite and ground station (feeder link) are not connected at the same point in time. In the S&F mode, a message is first sent to the ground station, which stores the message temporarily until it can verify that the recipient (the UE in the case of downlink transmission and the SCS / AS during the uplink transmission) is available or until the optimal time for delivery. Once conditions are favourable, the network forwards the message to the intended recipient.

[0042] A cell as described in the embodiment is associated with the area served by the ground station or satellite communication networks to describe the coverage areas of the satellite beams, enabling the UE to connect to the satellite communication network. In an embodiment of the disclosure, the term satellite is used, which actually represents at least one of Network Function (NF) or g Node B (gNB) which is onboard from a 3GPP perspective. The satellite system or satellite access as used or defined in this embodiment is applicable for both 5G systems with satellite access and / or 4G systems with satellite access or any Radio Access Technology (RAT) with satellite access. Further, the satellite constellation refers to a group of satellites placed in specific orbits working together as a system to provide network coverage.

[0043] In embodiment of the disclosure, Mobility Management Function (MME) onboard and MME on the ground station is used as an example, but this same concept can be applied to any of the network functions (NFs). The list of NFs, e.g., Session Management Function (SMF) / Packet Control Function (PCF) / Unified Data Management (UDM) / Authentication Server Function (AUSF) / Mobility Management Entity (MME) / Packet Gateway (P-GW) / Service Gateway (S-GW) / Home Subscriber Server (HSS) / Network Exposure Function (NEF) / Service Capability Exposure Function (SCEF). A Control Plane NF is composed of one or multiple NF Services. These multiple NF Service instances can be grouped into an NF Service Set if they are interchangeable with each other because they share the same context data. The ground NF (e.g., MME / AMF) also can be treated as a UDSF function with whom UE context data is synchronized by all the NFs onboard the satellite.

[0044] When the UE registers to the network in S&F mode and is available to send / receive data on specific occasions only (e.g., when satellites fly over and later connect to the ground station), it may be desirable to expose information such as the UE is registered in S&F mode, the feeder link is available, and others to the AF apparatus. For example, today the AF apparatus may send a message to the UE and expect the UE will reply in a certain time monitored by a guard timer. The AF apparatus may need to re-adjust all such applicable timers if the UE is in the S&F mode; thus, such information will help the AF apparatus to adjust its logic accordingly. Current systems do not define any method to indicate the estimated time of delivery of the data to the AF apparatus.

[0045] The present solution provides a method and system for indicating the estimated time to the AF apparatus. Providing the estimated data delivery time to the AF apparatus leads to enhanced service delivery with respect to aspects such as QoS, the data size, and scheduling of the retries of the data transmission. In an embodiment of the disclosure, the terms AF apparatus and SCS / AS are used interchangeably and have the same meaning. Similarly, the terms network and the satellite communication network are used interchangeably and possess the same meaning.

[0046] Referring now to the drawings and more particularly to Figs. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figure, these are shown preferred embodiments.

[0047] Fig. 1 is a block diagram that illustrates the hardware components associated with the ground station (100) for managing data delivery in the S&F mode within a satellite communication network according to an embodiment of the disclosure. With reference to Fig. 1, the ground station (100) may encompass a diverse range of devices including but not limited to Mobility Management Entity (MME), Session Management Function (SMF), Unified Data Management (UDM), Policy Control Function (PCF), Packet Gateway (PGW), and others. In an embodiment of the disclosure, the ground station (100) may include memory (101), a processor (102), an I / O interface (104), and a data delivery time controller (103).

[0048] The memory (101) stores instructions to be executed by the processor (102). The memory (101) can include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (101) may in some examples be considered a non-transitory storage medium. The term non-transitory may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term non-transitory should not be interpreted that the memory (101) is non-movable. In some examples, the memory (101) stores larger amounts of information. In certain examples, a non-transitory storage medium may store data that can over time change (e.g., in Random Access Memory (RAM) or cache). The memory (101) stores the information on whether the UE is registered on S&F mode, the availability of the feeder link, the downlink data shared by the AF apparatus (200), and others.

[0049] The processor (102) may include one or a plurality of processors. In an embodiment of the disclosure, the processor (102) may be communicatively coupled to (with) the memory (101).The one or the plurality of processors may be a general-purpose processor such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor (102) may include multiple cores and is configured to execute the instructions stored in the memory (101). The processor (102) fetches the feeder link availability information of the UE, information regarding the S&F mode registration. Further, the processor (102) retrieves instructions and executes them.

[0050] The I / O interface (104) transmits the information between the memory (101) and external peripheral devices. The peripheral devices are the input-output devices associated with the ground station (100). The I / O interface (104) receives several pieces of information from a plurality of UEs, network devices, servers, and the like. The I / O interface (104) ensures that the operating speed of the processor is synchronized with respect to the input and output devices. The I / O interface (104) establishes a connection between different peripheral devices like data delivery time controller, memory, switches, and others for managing the data delivery in the S&F mode within the satellite communication network for any scenario-specific action like when the UE is registered in the S&F mode, a change in previously reported values of Downlink S&F estimated Delivery Time, and a feeder link availability period, and others.

[0051] In an embodiment of the disclosure, the data delivery time controller (103) of the ground station (100) may communicate with the processor (102), the I / O interface (104), and the memory (101) for managing data delivery in the S&F mode within the satellite communication network. In an embodiment of the disclosure, the data delivery time controller (103) may be communicatively coupled to (with) the memory (101) and the processor (102) to estimate the data delivery in the satellite communication network. The data delivery time controller (103) may be configured to monitor the event, to determine the occurrence of the event, to determine the Downlink S&F estimated data delivery time, and to transmit the Downlink S&F estimated data delivery time to the AF apparatus (200).

[0052] In an embodiment of the disclosure, the data delivery time controller (103) may detect an event associated with the UE. The event may include at least one of the UE being registered successfully or camped on such cell in the S&F mode in response to the UE registering on a cell successfully or camped on a cell that supports the S&F mode in the satellite communication network, a change in previously reported values of Downlink S&F estimated Delivery Time, or a feeder link availability period. Further, the data delivery time controller (103) may determine feeder link availability information and expected delivery time information based on at least one of a satellite constellation(s) or a time until the next satellite connects to the ground station (100). Further, the data delivery time controller (103) may report the feeder link availability information and the expected delivery time information to the AF apparatus (200) upon detection of the event.

[0053] In an embodiment of the disclosure, the feeder link availability information may comprise information on when the feeder link will be available, wherein the feeder link is a link between the satellite and the ground station (100).

[0054] In an embodiment of the disclosure, the data delivery time controller (103) may monitor the event indicating at least one of the UE being registered in the S&F mode, a change in previously reported values of Downlink S&F estimated Delivery Time, or a feeder link availability period. Further, the data delivery time controller (103) may send a notification to the AF apparatus (200) based on an operator configuration, wherein the notification indicates at least one of the UE being registered in the S&F mode, the Downlink S&F estimated Delivery Time, the feeder link availability information, or the feeder link availability period.

[0055] Furthermore, the data delivery time controller (103) may receive a request to delete monitoring of the event from the SCS / AS in communication with an HSS and deletes the monitoring of the event.

[0056] In an embodiment of the disclosure, the data delivery time controller (103) may be included in the processor (102). In an embodiment of the present disclosure, the operations of the data delivery time controller (103) may be performed by the processor (102) using the data delivery time controller (103). In an embodiment of the disclosure, the operations of the data delivery time controller (103) may be performed by the processor (102) controlling the data delivery time controller (103).

[0057] Fig. 2 is a block diagram that illustrates the hardware components associated with the AF apparatus (200), according to an embodiment of the disclosure. The AF apparatus (200) may encompass a diverse range of devices including but not limited to Network Exposure Function (NEF), the service Capability Exposure Function (SCEF) and others. In an embodiment of the disclosure, the ground station (100) may include memory (201), a processor (202), an I / O interface (204), and a data delivery time controller (203).

[0058] The memory (201) stores instructions to be executed by the processor (202). The memory (201) can include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard disks, optical disks, floppy disks, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory (201) may in some examples be considered a non-transitory storage medium. The term non-transitory may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term non-transitory should not be interpreted that the memory (201) is non-movable. In some examples, the memory (201) stores larger amounts of information. In certain examples, a non-transitory storage medium may store data that can over time change (e.g., in Random Access Memory (RAM) or cache). The memory (201) stores the information on whether the UE is registered on S&F mode, the availability of the feeder link, the downlink data shared by the AF apparatus (200), and others.

[0059] The processor (202) may include one or a plurality of processors. In an embodiment of the disclosure, the processor (202) may be communicatively coupled to (with) the memory (201). The one or the plurality of processors may be a general-purpose processor such as a central processing unit (CPU), an application processor (AP), or the like, a graphics-only processing unit such as a graphics processing unit (GPU), a visual processing unit (VPU), and / or an AI-dedicated processor such as a neural processing unit (NPU). The processor (202) may include multiple cores and is configured to execute the instructions stored in the memory (201). The processor (202) fetches the feeder link availability information of the UE , information regarding the S&F mode registration. Further, the processor (202) retrieves instructions and executes them.

[0060] The I / O interface (204) transmits the information between the memory (201) and external peripheral devices. The peripheral devices are the input-output devices associated with the ground station (100). The I / O interface (204) receives several pieces of information from a plurality of UEs, network devices, servers, and the like. The I / O interface (204) ensures that the operating speed of the processor is synchronized with respect to the input and output devices. The I / O interface (204) establishes a connection between different peripheral devices like data delivery time controller, memory switches, and others for managing the data delivery in the S&F mode within the satellite communication network for any scenario-specific action like when the UE is registered in the S&F mode, a change in previously reported values of Downlink S&F estimated Delivery Time, and a feeder link availability period, and others.

[0061] In an embodiment of the disclosure, the data delivery time controller (203) may communicate with the processor (202), I / O interface (204), and memory (201) for managing the delivery of the data in the satellite communication system. In an embodiment of the disclosure, the data delivery time controller (203) may be communicatively coupled to (with) the memory (201) and the processor (202). The data delivery time controller (203) may receive a notification from a ground station (100) wherein the notification comprises an indication comprising the information like the UE is registered in the S&F mode, the Downlink S&F estimated Delivery Time, the feeder link availability information, and the feeder link availability period. Based on the received notification from the ground station (100), the data delivery time controller (203) may determine an expected data delivery time. Further, the data delivery time controller (203) may transmit the data to the UE based on the expected delivery time.

[0062] In an embodiment of the disclosure, the estimated data delivery time may be based on feeder link availability to deliver the data to an Evolved Packet Core (EPC) or a 5GC and to the satellite, the service link availability to deliver the data to the UE and receive an acknowledgment. Further, the estimated data delivery time may be based on the feeder link availability to deliver the acknowledgment to the EPC or the 5GC and deliver the acknowledgment back to the AF apparatus (200).

[0063] In an embodiment of the disclosure, the data delivery time controller (203) may modify a plurality of communication parameters based on the notification wherein the plurality of communication parameters comprises at least one of a frequency of data messages, a size of data messages, acknowledgment handling, or acknowledgment timers. Further, the data delivery time controller (203) may determine the feeder link availability and schedules the delivery of the data to the UE when the feeder link is available.

[0064] In an embodiment of the disclosure, the data delivery time controller (203) may determine a duration of availability of the feeder link to determine a time window within which a data packet can be delivered to the UE during a current satellite pass and the data delivery time controller (203) schedules the retransmission of the data packet based on at least one of the expected delivery time or a round trip time for data delivery and acknowledgment reception to the AF apparatus (200).

[0065] The data delivery time controller (103) and (203) may be innovative hardware components integrated into at least one of the ground station (100), the AF apparatus (200), or the UE via processing circuitry which includes logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, and various electronic and optical components. These circuits may be on semiconductor chips or substrates like printed circuit boards.

[0066] In an embodiment of the disclosure, the data delivery time controller (203) may be included in the processor (202). In an embodiment of the present disclosure, the operations of the data delivery time controller (203) may be performed by the processor (202) using the data delivery time controller (203). In an embodiment of the disclosure, the operations of the data delivery time controller (203) may be performed by the processor (202) controlling the data delivery time controller (203).

[0067] While Figs 1 and 2 illustrate the hardware components of the ground station and the AF apparatus, the alternative embodiments may include different or additional components. The labels or names of these elements are illustrative and do not limit the scope of the disclosure. Components may also be combined to perform similar functions.

[0068] Fig. 3 is a sequence diagram that illustrates the indication of the S&F event information to the AF apparatus (200), according to an embodiment of the disclosure.

[0069] The S&F satellite operation assumes intermittent connectivity between the UE-satellite-ground network. This operation is particularly suited for delivering delay-tolerant or non-real-time satellite services, such as CIoT / MTC SMS. To support the S&F satellite operation for these services, enhancements to the related UE and satellite communication network procedures are necessary. These enhancements include determining whether to inform the UE when the S&F satellite operation is applied. Additionally, during the S&F satellite operation, the AF apparatus (200) benefits from receiving the S&F event information from the ground station (100). This information aids the AF apparatus (200) and UE in enhancing service delivery and consumption, particularly regarding aspects such as QoS, data size, and scheduling. The proposed method may aim to expose the S&F event information from the ground station (100) to the AF apparatus (200) and UE.

[0070] When the User Equipment (UE) registers to the satellite communication network in Store and Forward (S&F) mode and is available to send / receive data only on specific occasions (e.g., when satellites fly over and later connect to the ground station), it may be desirable to expose certain information to the Application Function (AF) apparatus (200). This exposure will help the AF apparatus (200) adjust its logic accordingly.

[0071] The UE registered in S&F mode implies that the UE is registered in Next Generation Radio Access Network (NG-RAN) satellite access, but there is no simultaneous feeder link and service link. If the UE is registered in S&F mode, the AF apparatus (200) may need to adjust the frequency, size of data expected, Quality of Service (QoS), etc.

[0072] Information about when the feeder link will be available is crucial. This will help the AF apparatus (200) schedule delivery as and when the feeder link is available. For example, it may indicate a specific time (e.g., 11:00) or after a certain duration (e.g., 30 minutes), or it can indicate the frequency at which the feeder link will be available. i.e. it can be like feeder link will be

[0073] a) available at time 10 O Clock, 11 O clock, 12 O clock etc.

[0074] b) available after 30 minutes, 60 minutes 120 minutes. Minutes is used as an example it can be in seconds or hours or any other unit of time.

[0075] c) Time slot at which feeder link will be available for e.g. 10-11 O clock or 12 am to 1 pm or it can be 30 mins from now to 60 mins etc.

[0076] Any combination of above. It can be one or more values of any combination of above.

[0077] The expected delivery time for data involves the occurrence of several events. The feeder link must be available to deliver data to the EPC / 5GC and subsequently to the satellite. Additionally, the service link must be available to deliver data to the UE and receive an acknowledgment. Furthermore, the feeder link must be available to deliver the acknowledgment to the EPC / 5GC and subsequently to the AF apparatus (200).

[0078] This monitoring event is detected when the ground station (100) detects that the UE is registered in S&F mode or there is change in previously reported values of downlink S&F estimated Delivery Time and / or the feeder link availability period, the ground station sends to the SCS / AS that the UE is registered in S&F Mode, a Downlink S&F estimated Delivery Time and the feeder link availability period. If feeder link availability period is not included, the Downlink S&F estimated Delivery time is the estimated / expected time required to deliver the data to the UE from the time data has been received in the network. If feeder link availability period is included, the Downlink S&F estimated Delivery time is the estimated / expected time required to deliver the data to the UE after the feeder link is established.

[0079] Providing the expected delivery time of any data packet, signaling message, or similar communication sent from the AF apparatus (200) to the UE back to the AF apparatus (200) may be useful. This information allows for the scheduling and readjustment of retry timers and retry mechanisms accordingly. To achieve this, it is proposed to define new monitoring events and expose them via the NEF (400) or the AF apparatus (200). The following events, as provided in Table 1, are proposed to be added and exposed by the AMF, UDM, or a new NF in 3GPP networks. For LTE networks, it is proposed to add and expose the following events via the MME or HSS.

[0080]

[0081] Table 1

[0082] Fig. 3 is a sequence diagram that illustrates the exposure of the S&F event information to the AF apparatus (200) according to an embodiment of the disclosure. In operation S310, the AF apparatus (200) may send an Nnef_S&F_EventExposure_Subscribe Request to the NEF (400), requesting notifications for a UE or group of UEs related to S&F Satellite Operation for one or more of the following: Registration in S&F Mode, Feeder link availability, and S&F Delay Time.

[0083] The time or duration may be measured in at least one of the following forms. The time to deliver the data to the UE may be one such form. Another form may be the round trip time, which is the total time to deliver data to the UE and receive an acknowledgment. This round trip time can range from best effort to worst effort, for example, from 2 hours to 10 hours. For instance, if the first attempt to deliver the data fails and a second attempt is required, the time may increase accordingly. Additionally, the time at which any MO data / message can be initiated from the UE may be also considered.

[0084] In an example, the above elements may be known as the S&F event information in this embodiment. The AF apparatus (200) can register for one or more of these elements in any combination. The event reporting information may indicate the type of reporting requested, such as one-time reporting, periodic reporting, or event-based reporting for Monitoring Events. If the NEF authorizes the reporting event subscription, the NEF may record the association of the event trigger and the requester identity. The subscription may also include the maximum number of reports and / or the maximum duration of reporting IE.

[0085] In operation S320, the NEF (400) may send a request to subscribe to the "S&F event" in the Nnf_EventExposure_Subscribe request to the ground station (100). The NEF (400) may provide the associated notification endpoint of the event receiving NF. If the NEF (400) itself is not the event receiving NF, the NEF (400) may additionally provide the notification endpoint of itself besides the notification endpoint of the event receiving NF. The type of reporting requested may be defined by the event reporting information. If the requested subscription is authorized by the NF, the NF may record the association of the event trigger and the requester identity.

[0086] In an embodiment of the disclosure, any NF (like SMF, UDM, PCF) may subscribe to S&F events from another NF using the Nnf_EventExposure_Subscribe request. In operation S330, the ground station (100) may acknowledge the execution of the Nnf_EventExposure_Subscribe or the Nnf_EventExposure_Unsubscribe request. In operation S340, the NEF (400) may transmit Nnef_S&F_EventExposure_Subscribe / Unsubscribe Response to the AF apparatus (200). In operation S350 [Conditional - depending on the Event], the ground station (100) (e.g., AMF) may detect the monitored event (i.e., S&F event) occurs and may send the event report by means of the Nnef_S&F_EventExposure_Notify message to the notification endpoint of the Event Receiving NF (i.e., NEF). In operation S360, the NEF (400) may send Nnef_S&F_EventExposure_Notify with S&F event information to the AF apparatus (200).

[0087] In an embodiment of the disclosure, the NEF can provide the S&F event information to the AF apparatus (200) via the Request-Response method. In an embodiment of the disclosure, the S&F event information can be made available to the UE (300). In an embodiment of the disclosure, in an LTE network, it is proposed that Registration in S&F Mode, Feeder Link Available, and S&F Delay Time are exposed by the MME or HSS. In an embodiment of the disclosure, the Feeder Link availability information can be made available from the Operations Administration and Maintenance (OAM) entity.

[0088] Fig. 4 is a flow diagram that illustrates the method of transmitting the occurrence of the event, estimated data delivery time along with the feeder link availability information, according to an embodiment of the disclosure. In operation S410, the ground station (100) may detect an event associated with the UE (300). This event may comprise at least one of the following: the UE is registered in the S&F mode in response to registering on a cell that supports the S&F mode in the satellite communication network, a change in previously reported values of Downlink S&F estimated Delivery Time, or a feeder link availability period.

[0089] In operation S420, the ground station (100) may determine the feeder link availability information and expected delivery time information based on at least one of the availability of the satellite constellation(s) or the time until the next satellite connects to the ground station (100). In operation S430, the ground station (100) may report the feeder link availability information and the expected delivery time information to the AF apparatus (200). In an embodiment of the disclosure, the ground station (100) may report the information to the AF apparatus (200) upon detection of the event.

[0090] In an embodiment of the disclosure, the satellite communication network may include an MME-onboard on a satellite and the MME-ground on a ground station (100).

[0091] In an embodiment of the disclosure, the feeder link availability information may include information on when the feeder link will be available, which is a link between the satellite and the ground station (100).

[0092] In an embodiment of the disclosure, the ground station (100) may monitor the event indicating at least one of the UE is registered in the S&F mode, a change in previously reported values of a Downlink S&F estimated Delivery Time, or a feeder link availability period. Further, the ground station (100) may transmit the notification to a Service Capability Server / Application Server (SCS / AS) based on the operator configuration, wherein the notification indicates at least one of the UE is registered in the S&F mode, the Downlink S&F estimated Delivery Time, or the feeder link availability period.

[0093] In an embodiment of the disclosure, the ground station (100) may receive the request to delete monitoring of the event from the SCS / AS in communication with the HSS. Further, the ground station (100) may delete the monitoring of the event.

[0094] If the SCS / AS decides to cancel or add the monitoring event for certain UEs (i.e., one individual UE or a subset of UEs) in a group of UEs for which there is a configured Monitoring Event, the SCS / AS can send a Monitoring Request message including the Time To Last Triggered Report Indication (TLTRI) for Update corresponding to the existing monitoring event configuration and the External Identifier(s) or Mobile Station International Subscriber Directory Number(s) (MSISDN(s)) of the individual member UE(s) to be canceled or added with the operation indication, which is either cancellation or addition. The HSS may examine the Monitoring Request message, e.g., with regard to the existence of External Identifier or MSISDN or External Group Identifier, whether any included parameters are in the range acceptable for the operator, whether the monitoring event(s) is supported by the serving MME / SGSN, whether the group-basis monitoring event feature is supported by the serving MME / SGSN, or whether the monitoring event that shall be deleted or updated is valid. The HSS may store the SCEF Reference ID, the SCEF ID, Maximum Number of Reports, Monitoring Duration, and the SCEF Reference ID for Deletion as provided by the SCEF.

[0095] In an embodiment of the disclosure, the Downlink S&F estimated Delivery Time may be the estimated or expected time required to deliver the data to the UE from the time the data has been received in the satellite communication network when the feeder link availability period is not included.

[0096] In an embodiment of the disclosure, the Downlink S&F estimated Delivery Time may be the estimated or expected time required to deliver the data to the UE after the feeder link is established when the feeder link availability period is included.

[0097] Fig. 5 is a flow diagram that illustrates the method of transmission of the downlink data from the AF apparatus (200) to the UE based on the expected delivery time according to an embodiment of the disclosure. In operation S510, the AF apparatus (200) may receive the notification from a ground station (100), wherein the notification comprises an indication comprising at least one of a UE is registered in the S&F mode, a Downlink S&F estimated Delivery Time, feeder link availability information, or a feeder link availability period. In operation S520, the AF apparatus (200) may determine an expected delivery time required to deliver the data to the UE based on the notification. In an embodiment of the disclosure, the AF apparatus (200) may determine an expected delivery time required to deliver the data to the UE based on the registration information. In operation S530, the AF apparatus (200) may transmit the data to the UE based on the expected delivery time.

[0098] In an embodiment of the disclosure, the estimated delivery time may be based on the feeder link availability to deliver the data to an Evolved Packet Core (EPC) or a 5GC and to the satellite, the service link availability to deliver the data to the UE and receive an acknowledgment, and the feeder link availability to deliver acknowledgment to the EPC or the 5GC and deliver the acknowledgment back to the AF apparatus (200). In an embodiment of the disclosure, the AF apparatus (200) may modify the plurality of communication parameters based on the notification, wherein the plurality of communication parameters comprises at least one of a frequency of data messages, a size of data messages, acknowledgment handling, or acknowledgment timers. Further, the AF apparatus (200) may determine the feeder link availability and schedules the delivery of the data to the UE when the feeder link is available.

[0099] In an embodiment of the disclosure, the AF apparatus (200) may determine a duration of availability of the feeder link to determine a time window within which a data packet can be delivered to the UE during a current satellite pass. Further, the AF apparatus (200) may schedule retransmission of the data packet based on the at least one of the expected delivery time or the round trip time for data delivery and acknowledgment reception to the AF apparatus (200). In an embodiment of the disclosure, the event and the monitoring event may be used interchangeably and hold the same meaning. Similarly, the terms network and the satellite communication network may be used interchangeably.

[0100] Fig. 6 illustrates a entity in a wireless communication system according to an embodiment of the disclosure.

[0101] In an embodiment of the disclosure, the entity (600) may be at least of a UE (or terminal), a base station, gNB, eNB, a ground station, a onboard station, a satellite, a AF or a network function (e.g., NEF) in a core network(CN).

[0102] Referring to the FIG. 6, the entity (600) may include a processor (610), a transceiver (620) and memory (630). However, all of the illustrated components are not essential. The entity (600) may be implemented by more or less components than those illustrated in FIG. 6. In addition, the processor (610) and the transceiver (620) and the memory (630) may be implemented as a single chip according to another embodiment.

[0103] The aforementioned components will now be described in detail.

[0104] The processor (610) may include one or more processors or other processing devices that control the proposed function, process, and / or method. Operation of the entity (600) may be implemented by the processor (610).

[0105] The transceiver (620) may include a RF transmitter for up-converting and amplifying a transmitted signal, and a RF receiver for down-converting a frequency of a received signal. However, according to another embodiment, the transceiver (620) may be implemented by more or less components than those illustrated in components.

[0106] The transceiver (620) may be connected to the processor (610) and transmit and / or receive a signal. The signal may include control information and data. In addition, the transceiver (620) may receive the signal through a wireless channel and output the signal to the processor (610). The transceiver (620) may transmit a signal output from the processor (610) through the wireless channel.

[0107] The memory (630) may store the control information or the data included in a signal obtained by the entity (600). The memory (630) may be connected to the processor (610) and store at least one instruction or a protocol or a parameter for the proposed function, process, and / or method. The memory (630) may include read-only memory (ROM) and / or random access memory (RAM) and / or hard disk and / or CD-ROM and / or DVD and / or other storage devices.

[0108] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the embodiments as described herein.

Claims

1.A method performed by a ground station (100) in a satellite communication network, comprising:detecting, by the ground station (100), an event associated with a user equipment (UE), wherein the event comprises at least one of the UE is registered in a store and forward (S&F) mode in response to the UE registering on a cell that supports the S&F mode in the satellite communication network, a change in previously reported values of Downlink S&F estimated Delivery Time, or a feeder link availability period;determining, by the ground station (100), feeder link availability information and expected delivery time information based on at least one of availability of a satellite constellation or a time until a next satellite connects to the ground station (100); andreporting, by the ground station (100), the feeder link availability information and the expected delivery time information to an application function (AF) apparatus (200).2.The method of the claim 1, wherein the satellite communication network comprises a mobility management entity (MME)-onboard on a satellite and an MME-ground on the ground station (100).3.The method of the claim 1, wherein the feeder link availability information comprises information on when the feeder link will be available which is a link between the satellite and the ground station (100).4.The method of the claim 1, comprising:monitoring, by the ground station (100), the event indicating at least one of the UE is registered in the S&F mode, a change in previously reported values of a Downlink S&F estimated Delivery Time, or a feeder link availability period; andsending, by the ground station (100), a notification to a Service Capability Server / Application Server (SCS / AS) based on an operator configuration, wherein the notification indicates at least one of the UE is registered in the S&F mode, the Downlink S&F estimated Delivery Time, or the feeder link availability period.5.The method of the claim 4, comprising receiving, by the ground station (100), a request to delete monitoring of the event from the SCS / AS in communication with a Home Subscriber Server (HSS); and deleting, by the ground station, monitoring of the event.6.The method of the claim 4, wherein the Downlink S&F estimated Delivery Time is the estimated or expected time required to deliver data to the UE from a time the data has been received in the satellite communication network, when the feeder link availability period is not included.7.The method of the claim 4, wherein the Downlink S&F estimated Delivery Time is the estimated or expected time required to deliver data to the UE after the feeder link is established, when the feeder link availability period is included.8.A method performed by an application function (AF) apparatus (200) in a satellite communication network, comprising:receiving, by the AF apparatus (200), a notification from a ground station (100), wherein the notification comprises an indication comprising at least one of a UE is registered in a store and forward (S&F) mode, a Downlink S&F estimated Delivery Time, feeder link availability information or a feeder link availability period;determining, by the AF apparatus (200), an expected delivery time required to deliver data to the UE based on the notification; andtransmitting, by the AF apparatus (200), the data to the UE based on the expected delivery time.9.The method of the claim 8, wherein the estimated delivery time is based on at least one of:a feeder link availability to deliver the data to an Evolved Packet Core (EPC) or a 5GC and to the satellite;a service link availability to deliver the data to the UE and receive an acknowledgement; ora feeder link availability to deliver acknowledgement to the EPC or the 5GC and deliver the acknowledgement back to the AF apparatus (200).10.The method of the claim 8, comprises:modifying, by the AF apparatus (200), a plurality of communication parameters based on the notification, wherein the plurality of communication parameters comprises at least one of a frequency of data messages, a size of data messages, acknowledgement handling, or acknowledgement timers;determining, by the AF apparatus (200), the feeder link availability, andscheduling, by the AF apparatus (200), delivery of the data to the UE when the feeder link is available.11.The method of the claim 8, comprises:determining, by the AF apparatus (200), a duration of availability of the feeder link to determine a time window within which a data packet can be delivered to the UE during a current satellite pass; andscheduling, by the AF apparatus (300), retransmission of the data packet based on at least one of the expected delivery time, or a round trip time for data delivery and acknowledgement reception to the AF apparatus (200).12.A ground station (100) in a satellite communication network, comprising:memory (101); andat least one processor (102) coupled to the memory (101),wherein the at least one processor (102) is configured to:detect an event associated with a user equipment (UE), wherein the event comprises at least one of the UE is registered in a store and forward (S&F) mode in response to the UE registering on a cell that supports the S&F mode in the satellite communication network, a change in previously reported values of Downlink S&F estimated Delivery Time, or a feeder link availability period;determine feeder link availability information and expected delivery time information based on at least one of availability of a satellite constellation or a time until a next satellite connects to the ground station (100); andreport the feeder link availability information and the expected delivery time information to an application function (AF) apparatus (200).13.The ground station (100) of the claim 12, wherein the at least one processor (102) is further configured to:monitor the event indicating at least one of the UE is registered in the S&F mode, a change in previously reported values of a Downlink S&F estimated Delivery Time, or a feeder link availability period; andsend a notification to a Service Capability Server / Application Server (SCS / AS) based on an operator configuration, wherein the notification indicates at least one of the UE is registered in the S&F mode, the Downlink S&F estimated Delivery Time, or the feeder link availability period.14.The ground station (100) of the claim 12, wherein the at least one processor (102) is further configured to:receive a request to delete monitoring of the event from the SCS / AS in communication with a HSS; anddelete the monitoring of the event.15.An application function (AF) apparatus (200) in a satellite communication network, comprising:memory (201); andat least one processor (202) coupled to the memory (201),wherein the at least one processor (202) is configured to:receive a notification from a ground station, wherein the notification comprises an indication comprising at least one of a user equipment (UE) is registered in a store and forward (S&F) mode, a Downlink S&F estimated Delivery Time, feeder link availability information or a feeder link availability period;determine an expected delivery time required to deliver data to the UE based on the notification; andtransmit the data to the UE based on the expected delivery time.

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