Methods and systems for timer handling in satellite communication

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data rates. A method for timer handling in satellite communication is provided by a terminal. The method includes receiving, from a core network, configuration information on a timer for restricting an initiation of a non-stratum access (NAS) signaling procedure; starting the timer, based on a return of the terminal into a coverage provided by the core network via a satellite; determining whether a condition is satisfied, the condition including that the terminal is required to transmit user data having high priority; in case that the condition is satisfied, stopping the timer; and initiating the NAS signaling procedure for transmitting the user data.

Description

METHODS AND SYSTEMS FOR TIMER HANDLING IN SATELLITE COMMUNICATION

[0001] The disclosure relates to an operation of a satellite communication network. More particularly, the disclosure relates to systems and methods for timer handling in the satellite communication network.

[0002]

[0003] Fifth generation (5G) mobile communication technologies define implementation in a wide frequency band to enable a fast transmission rate and new services. Specifically, the 5G mobile communication technology can be implemented in an ultra-high frequency band ('above 6GHz') called millimeter wave (mmWave) such as 28GHz and 39GHz as well as in a sub 6GHz frequency band such as 3.5 gigahertz (3.5GHz). In addition, in the case of sixth generation (6G) mobile communication technology, which is called systems beyond 5G communication, implementation in a terahertz band (e.g., 95GHz to 3THz band) is being considered to achieve a transmission rate that is 50 times faster than the 5G mobile communication technology and an ultra low latency time that is reduced to 1 / 10.

[0004] In the early stages of the 5G mobile communication technology, with the goal of ensuring service support and performance requirements for enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), standardization has been made for beamforming and massive multi input multi output (MIMO) for mitigating a path loss of radio waves in a ultra-high frequency band and increase a transmission distance of the radio waves, support for various numerologies for efficient utilization of ultra-high frequency resources (operation of multiple subcarrier intervals, etc.) and dynamic operation of slot formats, initial access technology for supporting multi-beam transmission and broadband, definition and operation of a band-wide part (BWP), new channel coding methods, such as a low density parity check (LDPC) code for large-scale data transmission and a polar code for high reliable transmission of control information, L2 pre-processing, network slicing providing a dedicated network specialized for a specific service, etc.

[0005] Currently, discussions are underway for improvement and performance enhancement of the initial 5G mobile communication technology in consideration of services that the 5G mobile communication technology is intended to support, and physical layer standardization is in progress for technologies such as vehicle-to-everything (V2X) to help autonomous vehicles determine their driving based on their own locations and status information that the autonomous vehicles transmit and to increase user convenience, new radio unlicensed (NR-U) for system operation that meets various regulatory requirements in an unlicensed band, NR terminal low power consumption technology (user equipment (UE) power saving), a non-terrestrial network (NTN) that is terminal-satellite direct communication to secure coverage in areas where communication with a terrestrial network is impossible, and positioning.

[0006] In addition, standardization of wireless interface architecture / protocol fields is in progress for technologies such as industrial Internet of Things (IIoT) for supporting new services through linkage and convergence with other industries, integrated access and backhaul (IAB) that integrates and supports wireless backhaul links and access links to provide nodes for expanding network service areas, mobility enhancement including conditional handover and dual active protocol stack (DAPS) handover, and 2-step Random Access Channel (RACH) for NR that simplifies random access procedures, and standardization of system architecture / service fields is also in progress for 5G baseline architecture (e.g., service based architecture, and service based interface) for combining network functions virtualization (NFV), software-defined networking (SDN) technology, mobile edge computing (MEC) that receives services based on a location of a terminal, etc.

[0007] When such 5G wireless systems are commercialized, an explosive increase in connected devices will be connected to a communication network, so, it is expected that the enhanced functions and performance of the 5G wireless systems and the integrated operation of the connected devices will be required. To this end, new research is expected to be conducted on eXtended reality (XR) to efficiently support augmented reality (AR), virtual reality (VR), and mixed reality (MR), etc., improvement in 5G performance and reduction in complexity using artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, drone communications, etc.

[0008] In addition, the development of these 5G wireless systems may serve as a basis for the development of not only multi-antenna transmission technology such as new waveform, full dimensional MIMO (FD-MIMO), array antenna, and large scale antenna to ensure coverage in the terahertz band of 6G mobile communication technology, high-dimensional spatial multiplexing technology using metamaterial-based lenses and antennas and orbital angular momentum (OAM) to improve the coverage of terahertz band signals, and reconfigurable intelligent surface (RIS) technology, but also full duplex technology for enhancing frequency efficiency and improving a system network of 6G mobile communication technology, AI-based communication technology that utilizes satellite and artificial intelligence (AI) from the design stage and incorporates end-to-end AI support functions to realize system optimization, and next generation distributed computing technology that realizes services with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources, etc.

[0009]

[0010] In discontinuous coverage of a satellite scenario, user equipment's (UEs) may have coverage at only specific times and places due to the continuous movement of satellites or satellite constellations. Due to the Discontinuous coverage, the UE may have access to satellite service coverage only at specific time and places.

[0011] In the discontinuous coverage of the satellite scenario, the UEs are bound to have coverage at only specific times due to the continuous movement of the satellites or the satellite constellations. The UE may determine that the UE is about to leave network coverage based on coverage information or any other information, e.g. satellite ephemeris, while the UE is in either connected or idle mode.

[0012] When the UEs are about to get the satellite coverage after a specific time, the UE may initiate signalling towards the network due to any uplink (UL) Traffic or non-access stratum (NAS) layer signalling. Similarly, if the network has buffered any downlink data, the network may page the UE on determining that the UE is back in coverage. The network may also trigger any down link (DL) signalling if the network determines that the UE is back in coverage.

[0013]

[0014] Few of the power saving mechanisms / timers / parameters, but not restricted or limited to only these, are:

[0015] I. Active Time / mobile initiated communication only (MICO) mode with Active Time;

[0016] II. Extended Connected Time / MICO mode with Extended Connected time;

[0017] III. Periodic tracking area update (TAU) Timer / Periodic Update Timer;

[0018] IV. Periodic Registration Timer / Periodic Registration Update Timer; and

[0019] V. Extended discontinuous reception (eDRX) parameters (such as cycle length).

[0020]

[0021] For a 5G system with satellite access, the following requirements apply:

[0022] - The 5G system shall support service continuity between NR terrestrial access network and NR satellite access networks owned by the same operator or owned by 2 different operators having an agreement.

[0023]

[0024] In order to reduce the impact due to large number of UEs triggering signalling load on the network returning after the discontinuous coverage, an Access and Mobility Management Function　(AMF) entity determines the "wait range" based on network configuration and sends the "DisCo Wait Range" to the UE via a Registration procedure or a UE Configuration Update procedure. The "Disco Wait Range" is a discontinuous time wait range for the UE comes back from the discontinuous coverage time. If the UE has decided to remain in no service (e.g. by applying power saving) due to the discontinuous coverage and waits until the same radio access technology (RAT) or public land mobile network (PLMN) coverage to return, the UE will calculate (or compute) the "wait timer" based on the "Disco Wait Range" configuration from the network (e.g. by selecting a random value between 0 and "Disco Wait Range"). The UE starts the respective "wait timer" while returning to coverage after being in the discontinuous coverage to reduce signalling overload on the same RAT or the PLMN. The UE will not initiate any NAS signalling when the "wait timer" is running.

[0025] The UE 102 may perform NAS procedure to indicate to the core network that the UE 102 wants to enter or exit unavailability period. When more than one UEs in a particular area enter or exit unavailability period at the same time can cause congestion in the core network. To avoid such congestions, the network provides a "discontinuous coverage maximum time offset" to every UE, during NAS procedures. Before entering the NAS procedure for entering unavailability, every UE will wait for a random time greater than zero and lesser than the "discontinuous coverage maximum time offset" before the UE can trigger the NAS procedure with network. Similarly, when the UE exits unavailability period, the UE may wait for the random time greater than zero and lesser than "discontinuous coverage maximum time offset" before the UE can trigger the NAS procedure with network. Setting (or Configuring) a timer for triggering of NAS procedures from different UEs at different points of time, and avoid congestion in the network. Although there are some exceptions for some procedures, when the UE is running the timer, and expecting to enter back in coverage / exit unavailability.

[0026] As per 3GPP TS 24.301, the UE shall not initiate any signalling when the "discontinuous coverage maximum time offset" is running in the UE. But there can be specific cases or procedures in the UE, which should not be delayed, and should be initiated immediately, even when the above timer is running in the UE. These are procedures or cases which need to exempt from being delayed, due to "discontinuous coverage maximum time offset" running in the UE.

[0027]

[0028] In an example herein, the UE may be accessing PLMN-A, in 4G or 5G access technology, via the satellite communication network. The satellite may move away from current geographical position of the UE, and the UE is in unavailability period or enters the discontinuous coverage time. The UE may have earlier saved the "discontinuous coverage maximum time offset" value indicated by network. Now for example, the UE may be expecting to enter back in coverage or end unavailability period at 12 pm, the same day the UE entered discontinuous coverage. When the UE is back in coverage at 12 pm, the UE starts timer with timer value greater than zero and lesser than the "discontinuous coverage maximum time offset". The UE may determine that the UE has pending "mobile originated (MO) exception data" before the timer expires. According to the current solutions, the UE will continue to run the timer for "discontinuous coverage maximum time offset" and wait for the timer expiry, before the UE can send "MO exception data". Waiting for the timer to expire even in the case of an exceptional event may lead to failure in sending of "MO exception data", and possibly failure in sending some critical data from the UE.

[0029] In another example, the UE may be accessing PLMN-A, in 4G or 5G access technology, via the satellite communication network. The satellite may move away from current geographical position of the UE, and the UE is in unavailability period or the UE starts the discontinuous coverage time. The UE may have earlier saved the "discontinuous coverage maximum time offset" value indicated by network. Now for example, the UE is expecting to enter back in coverage or end unavailability period, at 12 pm, the same day the UE entered the discontinuous coverage. The UE may start the timer at 12pm with timer value greater than zero and lesser than the "discontinuous coverage maximum time offset". The UE may either be the UE configured to use access class (AC) 11 - 15 in selected PLMN or the UE configured for high priority access in selected PLMN, and the UE has to perform NAS signalling or send out some data to the network. According to the current solutions the UE will continue to run the timer for "discontinuous coverage maximum time offset" and wait for the timer expiry, before the UE can send out any NAS signalling or data to the network / satellite. Waiting for the timer to expire may lead to delay in sending signalling messages or data from the UE that is configured for high priority access. The UE that is the UE configured to use AC 11 - 15 in selected PLMN or the UE configured for high priority access in selected PLMN is actually configure for higher priority access, which is differentiated by the access class values configured for the UE. Typically, in 3GPP definitions, access classes 11-15 are considered as high priority access class devices. High priority access class devices means any NAS signalling message or data packets which are sent out from such UEs need to be considered as higher priority over devices, which are not configured with access class 11-15.

[0030]

[0031] With the above description and the development of the wireless systems, various services may be provided. Therefore, methods for providing these services effectively are required.

[0032] The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.

[0033]

[0034] Aspects of the disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below.

[0035] Accordingly, an aspect of the disclosure is to disclose systems and methods for discontinuous coverage maximum time offset timer handling in satellite communication.

[0036] Another aspect of the disclosure is to disclose systems and methods for discontinuous coverage maximum time offset timer handling in satellite communication for MO exception data or a UE configured for high priority access, or a UE configured with access identity 11 to 15.

[0037] Another aspect of the disclosure is to disclose systems and methods for determining whether the UE has to transmit user data related to an exceptional event over the satellite communication when a discontinuous coverage maximum time offset timer is running in the UE.

[0038] Another aspect of the disclosure is to disclose systems and methods for determining whether the UE is allowed to use exception data reporting.

[0039] Another aspect of the disclosure is to disclose systems and methods for stopping the discontinuous coverage maximum time offset timer, on determining that the UE has to transmit the user data related to the exceptional event.

[0040] Another aspect of the disclosure is to disclose systems and methods for initiating a non-access Stratum (NAS) signaling for transmitting the user data related to the exceptional event.

[0041] Another aspect of the disclosure herein is to disclose systems and methods for determining, when a discontinuous coverage maximum time offset timer is running in the UE, whether the UE is configured as at least one of: UE configured to use AC 11 - 15 in selected PLMN, UE configured for high priority access in selected PLMN, or UE configured for high priority access in selected standalone non public network (SNPN).

[0042] Another aspect of the disclosure is to disclose systems and methods for stopping the discontinuous coverage maximum time offset timer.

[0043] Another aspect of the disclosure is to disclose systems and methods for initiating non-access stratum (NAS) signaling for transmitting the user data from the UE having high priority access.

[0044]

[0045] In accordance with an aspect of the disclosure, a method performed by a terminal in a wireless communication system is provided. The method includes receiving, from a core network, configuration information on a timer for restricting an initiation of a non-stratum access (NAS) signaling procedure; starting the timer, based on a return of the terminal into a coverage provided by the core network via a satellite; determining whether a condition is satisfied, the condition including that the terminal is required to transmit user data having high priority; in case that the condition is satisfied, stopping the timer; and initiating the NAS signaling procedure for transmitting the user data.

[0046] In an accordance with another aspect of the disclosure, a terminal in a wireless communication system is provided. The terminal includes a transceiver; and a processor coupled with the transceiver and configured to receive, from a core network, configuration information on a timer for restricting an initiation of a non-stratum access (NAS) signaling procedure, start the timer, based on a return of the terminal into a coverage provided by the core network via a satellite, determine whether a condition is satisfied, the condition including that the terminal is required to transmit user data having high priority, in case that the condition is satisfied, stop the timer, and initiate the NAS signaling procedure for transmitting the user data.

[0047] 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 should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope thereof, and the embodiments herein include all such modifications.

[0048]

[0049] According to an embodiment of the disclosure, by stopping the wait timer configured in the terminal, a signal may be transmitted to the network without delay in a discontinuous coverage environment in satellite communication system.

[0050] Furthermore, according to an embodiment of the disclosure, when the terminal is required to transmit MO exception data to the network or is configured as a high-priority UE, the terminal may immediately transmit the data or NAS signaling to the network, thereby minimizing transmission failures and ensuring a reliable communication system.

[0051] The effects obtainable in the disclosure are not limited to the above-mentioned effects, and other effects not mentioned herein will be clearly understood from the following description by those skilled in the art to which the disclosure belongs.

[0052]

[0053] The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0054] Figure 1a illustrates a sequence diagram showing a scenario when a UE has to transmit user data related to an exceptional event in the discontinuous coverage;

[0055] Figure 1b illustrates a sequence diagram showing a scenario when the UE has to transmit a high priority data in the discontinuous coverage;

[0056] Figure 2a is a block diagram illustrating satellite network for discontinuous coverage maximum time offset timer handling in satellite communication, according to embodiments of the disclosure;

[0057] Figure 2b is a block diagram illustrating a schematic overview of a wireless network for timer handling in satellite communication, according to the embodiments of the disclosure;

[0058] Figure 3 illustrates a sequence diagram of a scenario for discontinuous coverage maximum time offset timer handling in satellite communication for MO exception data, according to embodiments of the disclosure;

[0059] Figure 4 illustrates a flowchart for a method for timer handling in the satellite communication, according to embodiments of the disclosure;

[0060] Figure 5 is a block diagram illustrating a schematic overview of the wireless network for timer handling in the satellite communication, according to the embodiments of the disclosure;

[0061] Figure 6 illustrates a sequence diagram of a scenario for discontinuous coverage maximum time offset timer handling in satellite communication for a UE configured for high priority access, according to embodiments of the disclosure; and

[0062] Figure 7 illustrates a flowchart for a method for timer handling in the satellite communication, according to embodiments of the disclosure.

[0063]

[0064] 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 detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0065] Terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

[0066] The definitions (as defined herein) will apply and whenever appropriate the terms used in singular will also include the plural and vice versa. It is to be understood that the terminology used herein is for the purposes of describing particular embodiments only and is not intended to be limiting.

[0067] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0068] As such, before undertaking the detailed description below, it can be advantageous to set forth definitions of certain words and phrases used herein. The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms "transmit," "receive," and "communicate," as well as derivatives thereof, encompass both direct and indirect communication. For example, the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation. The term "or" is inclusive, meaning and / or. The phrase "associated with," as well as derivatives thereof, means to include, be included within, connect to, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term "controller" means any device, system or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items can be used, and only one item in the list can be needed. For example, "at least one of: A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. For example, "at least one of: A, B, or C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0069] Various functions described below may be implemented or supported by one or more computer programs, each of which is formed from computer-readable program code or machine-readable instructions and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer-readable program code or machine-readable instructions. Moreover, the phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium capable of being accessed by a computer, such as Read-Only Memory (ROM), Random Access Memory (RAM), a hard disk drive, a Compact Disc (CD), a Digital Versatile Disc (DVD), or any other type of memory. A "non-transitory" computer-readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer-readable medium includes media where data can be permanently stored and media where data may be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0070] Terms used herein to describe the embodiments are not intended to limit and / or define the scope of the disclosure. Unless otherwise defined, the technical terms or scientific terms used in the disclosure shall have the ordinary meaning understood by those with ordinary skills in the art to which the disclosure belongs.

[0071] It should be understood that "first", "second" and similar words used in the disclosure do not express any order, quantity or importance, but are only used to distinguish different components.

[0072] The words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.,", "i.e.," are merely used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein using the words / phrases "exemplary", "example", "illustration", "in an instance", "and the like", "and so on", "etc.", "etcetera", "e.g.,", "i.e.," is not necessarily to be construed as preferred or advantageous over other embodiments. As used herein, any reference to "one example" or "example", and "one embodiment" or "embodiment" means that particular elements, features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment. The phrases "in one embodiment" or "in one example" appearing in different places do not necessarily refer to the same embodiment.

[0073] Additionally, it will be further understood that similar words such as the term "include" or "comprise" mean that elements or objects appearing before the word encompass the listed elements or objects appearing after the word and their equivalents, but other elements or objects are not excluded. Similar words such as "connect" or "connected" are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Upper", "lower", "left" and "right" are only used to express a relative positional relationship, and when an absolute position of the described object changes, the relative positional relationship may change accordingly.

[0074] When it is considered that some detailed explanations about functions or configurations may unnecessarily obscure the essence of the disclosure, these detailed explanations will be omitted. All terms (including descriptive or technical terms) used herein should be interpreted as having meanings apparent to those of ordinary skill in the art. These terms, however, may have different meanings according to the intention of those of ordinary skill in the art, precedents or the emergence of new technologies, and therefore, the terms used herein must be defined based on the meanings of these terms together with the description provided herein.

[0075] For example, the base station may be at least one of a gNode B, an eNode B (eNB), a Node B, a radio access unit, a base station controller, and a node on a network. The terminal may include a user equipment (UE), a mobile station (MS), a mobile phone, a smart phone, a computer or multimedia system capable of performing communication functions. In some embodiments of the disclosure, the downlink (DL) is a wireless transmission path through which signals are transmitted from a base station to a terminal, and the uplink (UL) is a wireless transmission path through which signals are transmitted from a terminal to a base station.

[0076] Accordingly, the various embodiments discussed below for describing the principles of the disclosure herein are for illustration purposes only and should not be interpreted as limiting the scope of the disclosure in any way. Those skilled in the art will understand that the principles of the disclosure may be implemented in any suitably arranged wireless communication system. Although the following detailed description of the embodiments of the disclosure will be directed to 5G, those skilled in the art can understand that the main points of the disclosure may also be applied to other communication systems (for example, beyond 5G (B5G) or 6G) with similar technical backgrounds and channel formats with slight modifications without departing from the scope of the disclosure.

[0077] Embodiments herein may be described and illustrated in terms of blocks which carry out a described function or functions. These blocks, which may be 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 may optionally be driven by a firmware. The circuits may, 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 may 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 may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure.　Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.

[0078] It should be noted that elements in the drawings are illustrated for the purposes of this description and ease of understanding and may not have necessarily been drawn to scale. For example, the flowcharts / sequence diagrams illustrate the method in terms of the steps required for understanding of aspects of the embodiments as disclosed herein. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Furthermore, in terms of the system, one or more components / modules which comprise the system may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the present embodiments so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0079] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any modifications, equivalents, and substitutes in addition to those which are particularly set out in the accompanying drawings and the corresponding description. Usage of words such as first, second, third etc., to describe components / elements / steps is for the purposes of this description and should not be construed as sequential ordering / placement / occurrence unless specified otherwise.

[0080] The embodiments herein achieve methods and systems for timer handling in satellite communication.

[0081]

[0082] When the discontinuous coverage maximum time offset timer is running in a user equipment (UE), then ideally the UE has already come back to the satellite network coverage again. However, the UE may wait till discontinuous coverage maximum time offset timer expiry to ensure not all UEs are trying to access the network at the same time to indicate that they are back from coverage.

[0083] As per 3rd generation partnership project (3GPP) technical specification (TS) 24.301, the UE shall not initiate any signalling when the "discontinuous coverage maximum time offset" timer is running in the UE. However, there can be specific cases or procedures in the UE, which should not be delayed, and should be initiated immediately, even when the above timer is running in the UE.

[0084] These are procedures or cases which need to exempt from being delayed, due to "discontinuous coverage maximum time offset" running in the UE. Such cases are when the UE determines that the UE has to send user data related an exceptional event, the UE is a UE configured to use AC 11 - 15 in selected PLMN, the "UE configured for high priority access in selected PLMN", or the "UE configured for high priority access in selected SNPN" while the discontinuous maximum time offset timer is running in the UE. The UE may stop timer for "discontinuous coverage maximum time offset" upon determining that the UE is configured to send MO exception data, the UE is the UE configured for high priority access in selected PLMN or the SNPN, or the UE 202 can be a configured with one or more access identities equal to 1, 2, or 11-15 applicable in the selected PLMN or SNPN as specified in 3GPP TS 24.501 and perform NAS signalling if required.

[0085] The procedure ensures that high priority data is sent (or transmitted) to the network without any delay to ensure uninterrupted services, and avoids failures in applications configured for high priority access.

[0086]

[0087] The following definitions and abbreviations have been referred to herein:

[0088] NTN: non-terrestrial networks

[0089] TER: terrestrial

[0090] UE: user equipment

[0091] SAT: satellite

[0092] eNB: evolved node-B

[0093] TN: terrestrial networks

[0094] gNB: next generation node-B

[0095] PLMN: public land mobile network

[0096] EPC: evolved packet core

[0097] 5GC: 5G core

[0098] 2G: 2nd generation of mobile networks

[0099] 3G: 3rd generation of mobile networks

[0100] HPLMN: home PLMN

[0101] DC: discontinuous coverage

[0102] VPLMN: visited PLMN

[0103] GPS: global positioning system

[0104] AS: access stratum

[0105] DRX: discontinuous reception

[0106] NAS: non-access stratum

[0107] eDRX: extended discontinuous reception

[0108] DL: downlink

[0109] AMF: access and mobility management function

[0110] UL: uplink

[0111] GEO: geostationary orbit

[0112] NW: network

[0113] LEO: low earth orbit

[0114] QoS: quality of service

[0115] MEO: medium earth orbit

[0116] RAT: radio access technology

[0117] MICO: mobile initiated communication only

[0118] EPS: evolved packet system

[0119] MCS: mission critical service

[0120] E-UTRA: evolved universal mobile telecommunication access

[0121] MPS: multimedia priority service

[0122] NG-RAN: next generation radio access network

[0123] 3GPP: third generation partnership project

[0124] EUTRAN: evolved universal mobile telecommunication access network

[0125] TAU: tracking area update

[0126] USIM: universal subscriber identification module

[0127] RU: registration update

[0128] Uu: the radio interface between the UE and the node B

[0129] OOS: out of service

[0130] Satellite: an artificial body placed in orbit round the earth or moon or another planet in order to collect information or for communication.

[0131] Satellite Constellation: a group of satellites, placed in orbit round the earth or moon or another planet in order to collect information or for communication.

[0132] Service User: an individual who has received a priority level assignment from a regional / national authority (i.e., an agency authorised to issue priority assignments) and has a subscription to a mobile network operator

[0133] PDU: packet data unit

[0134] PDN: packet data network

[0135] NR: new radio

[0136] PLMN ID: PLMN identity

[0137] EHPLMN: equivalent home PLMN

[0138] EPLMN: equivalent PLMN

[0139] MCC: mobile country code

[0140] TAC: tracking are code

[0141] TAI: tracking are identity

[0142]

[0143] SNPN: standalone non-public networks

[0144] RSNPN: Registered SNPN

[0145] NPN: non-public networks

[0146] eNPN: Enhanced NPN

[0147] LADN: local area data network

[0148] MNC: mobile network code

[0149] PSM: power saving mode

[0150] CAG: Closed Access Group

[0151] UDM: Unified data management

[0152] EMM: EUTRA mobility management

[0153] 5GMM: 5G mobility management

[0154] DisCo: discontinuous coverage

[0155] eSIM: embedded subscriber identity module

[0156] RPLMN: registered PLMN

[0157]

[0158] An example list of NAS messages are as follows, which are not limited to: REGISTRATION REQUEST message; DEREGISTRATION REQUEST message; SERVICE REQUEST message; CONTROL PLANE SERVICE REQUEST; IDENTITY REQUEST; AUTHENTICATION REQUEST; AUTHENTICATION RESULT; AUTHENTICATION REJECT; REGISTRATION REJECT; DEREGISTRATION ACCEPT; SERVICE REJECT; SERVICE ACCEPT; UE CONFIGURATION UPDATE command; UE PARAMETERS UPDATE command, and so on.

[0159]

[0160] The term 5GMM sublayer states in this embodiment are at least one of the below:

[0161] 1) 5GMM-NULL

[0162] 2) 5GMM-DEREGISTERED

[0163] a) 5GMM-DEREGISTERED.NORMAL-SERVICE

[0164] b) 5GMM-DEREGISTERED.LIMITED-SERVICE

[0165] c) 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION

[0166] d) 5GMM-DEREGISTERED.PLMN-SEARCH

[0167] e) 5GMM-DEREGISTERED.NO-SUPI

[0168] f) 5GMM-DEREGISTERED.NO-CELL-AVAILABLE

[0169] g) 5GMM-DEREGISTERED.eCALL-INACTIVE

[0170] h) 5GMM-DEREGISTERED.INITIAL-REGISTRATION-NEEDED

[0171] 3) 5GMM-REGISTERED-INITIATED

[0172] 4) 5GMM-REGISTERED

[0173] a) 5GMM-REGISTERED.NORMAL-SERVICE

[0174] b) 5GMM-REGISTERED.NON-ALLOWED-SERVICE

[0175] c) 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE

[0176] d) 5GMM-REGISTERED.LIMITED-SERVICE

[0177] e) 5GMM-REGISTERED.PLMN-SEARCH

[0178] f) 5GMM-REGISTERED.NO-CELL-AVAILABLE

[0179] g) 5GMM-REGISTERED.UPDATE-NEEDED

[0180] 5) 5GMM-DEREGISTERED-INITIATED

[0181] 6) 5GMM-SERVICE-REQUEST-INITIATED

[0182]

[0183] In this embodiment the term EMM sublayer states are at least one of the below:

[0184] 1) EMM-NULL

[0185] 2) EMM-DEREGISTERED

[0186] a) EMM-DEREGISTERED.NORMAL-SERVICE

[0187] b) EMM-DEREGISTERED.LIMITED-SERVICE

[0188] c) EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH

[0189] d) EMM-DEREGISTERED.PLMN-SEARCH

[0190] e) EMM-DEREGISTERED.NO-IMSI

[0191] f) EMM-DEREGISTERED.ATTACH-NEEDED

[0192] g) EMM-DEREGISTERED.NO-CELL-AVAILABLE

[0193] h) EMM-DEREGISTERED.eCALL-INACTIVE

[0194] 3) EMM-REGISTERED-INITIATED

[0195] 4) EMM-REGISTERED

[0196] a) EMM-REGISTERED.NORMAL-SERVICE

[0197] b) EMM-REGISTERED.ATTEMPTING-TO-UPDATE

[0198] c) EMM-REGISTERED.LIMITED-SERVICE

[0199] d) EMM-REGISTERED.PLMN-SEARCH

[0200] e) EMM-REGISTERED.UPDATE-NEEDED

[0201] f) EMM-REGISTERED.NO-CELL-AVAILABLE

[0202] g) EMM-REGISTERED.ATTEMPTING-TO-UPDATE-MM

[0203] h) EMM-REGISTERED.IMSI-DETACH-INITIATED

[0204] 5) EMM-DEREGISTERED-INITIATED

[0205] 6) EMM-TRACKING-AREA-UPDATING-INITIATED

[0206] 7) EMM-SERVICE-REQUEST-INITIATED

[0207]

[0208] The term RAT as defined in this embodiment can be one of the following: NG-RAN, 5G, 4G, 3G, 2G, EPS, 5GS, NR, NR in unlicensed bands, NR (LEO) satellite access, NR (MEO) satellite access, NR (GEO) satellite access, NR (OTHERSAT) satellite access, NR RedCap, E-UTRA, E-UTRA in unlicensed bands, NB-IoT, WB-IoT, LTE-M,

[0209]

[0210] The 5GS registration types can be initial registration, mobility registration updating, periodic registration updating, emergency registration, SNPN onboarding registration, disaster roaming initial registration, disaster roaming mobility registration updating, and so on.

[0211] PLMN selection as per 23.122 without RPLMN:

[0212]

[0213] The UE may select and attempt registration on any PLMN or access technology combinations, if available and allowable, in the following order:

[0214] - either the HPLMN (if the EHPLMN list is not present or is empty) or the highest priority EHPLMN that is available (if the EHPLMN list is present).

[0215] - each PLMN / access technology combination in the "User Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order).

[0216] - each PLMN / access technology combination in the "Operator Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order) or stored in the ME (in priority order).

[0217] - other PLMN / access technology combinations with received high quality signal in random order.

[0218] - other PLMN / access technology combinations in order of decreasing signal quality.

[0219]

[0220] PLMN selection as per 23.122 with RPLMN: The UE selects and attempts registration on any PLMN or access technology combinations, if available and allowable, in the following order:

[0221] - either the RPLMN or the Last registered PLMN.

[0222] - either the HPLMN (if the EHPLMN list is not present or is empty) or the highest priority EHPLMN that is available (if the EHPLMN list is present).

[0223] - each PLMN / access technology combination in the "User Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order).

[0224] - each PLMN / access technology combination in the "Operator Controlled PLMN Selector with Access Technology" data file in the SIM (in priority order) or stored in the ME (in priority order).

[0225] - other PLMN / access technology combinations with received high quality signal in random order.

[0226] - other PLMN / access technology combinations in order of decreasing signal quality.

[0227]

[0228] The NTN and TN could either operate in two different frequency bands (e.g., FR1 vs FR2), or in same frequency band (e.g., FR1 or FR2).

[0229] The terms Satellite 3GPP access, Satellite access, Satellite Access Network, NR Satellite Access Network, Satellite NG-RAN Access Technology and NR Satellite access have been interchangeably used and have the same meaning.

[0230] The methods, issues or solutions disclosed in this embodiment are explained using NR satellite access or Satellite NG-RAN Access Technology as an example and is not restricted or limited to NR Satellite access only. However, the solutions proposed in this embodiment are also applicable for Satellite E-UTRAN access Technology, NB (Narrow Band)-S1 mode or WB (Wide Band)-S1 mode via satellite E-UTRAN access and / or NB-IOT (Narrowband Internet of Things) or WB-IOT (Wideband Internet of Things) Satellite Access / Architecture.

[0231] The solutions that are defined for NR(5GC) are also applicable to legacy RATs like E-UTRA / LTE, the corresponding CN entities needs to be replaced by LTE entities; for e.g., AMF with MME, g-nodeB with e-nodeB, UDM with HSS etc. But the principles of the solution remain the same.

[0232] An example list of NAS messages can be, but not limited to, REGISTRATION REQUEST message; DEREGISTRATION REQUEST message; SERVICE REQUEST message; CONTROL PLANE SERVICE REQUEST; IDENTITY REQUEST; AUTHENTICATION REQUEST; AUTHENTICATION RESULT; AUTHENTICATION REJECT; REGISTRATION REJECT; DEREGISTRATION ACCEPT; SERVICE REJECT; SERVICE ACCEPT, and so on.

[0233] The Network used in this embodiment is explained using any 5G Core Network Function; for e.g., AMF. However, the network could be any 5G / EUTRAN Core Network Entities like AMF / SMF / MME / UPF or the Network could be any 5G / EUTRAN RAN Entity like eNodeB (eNB) or gNodeB (gNB) or NG-RAN etc.

[0234] The messages used or indicated in this embodiment are shown as an example. The messages could be any signalling messages between UE and the Network Functions / Entities or between different Network functions / entities.

[0235] The term 'area / location / geographical area' used in this embodiment may refer to any of cell / cell ID, TAC / TAI, PLMN, MCC / MNC, Latitude / longitude, CAG cell or any geographical location / coordinate.

[0236] The methods, issues or solutions disclosed in this embodiment are explained using NR access or NG-RAN Access Technology as an example and are not restricted or limited to NR access only. However, the solutions proposed in this embodiment are also applicable for E-UTRAN access Technology, NB (Narrow Band)-S1 mode or WB (Wide Band)-S1 mode via E-UTRAN access and / or NB-IOT (NarrowBand Internet of Things) or WB-IOT (Wideband Internet of Things) Access / Architecture.

[0237] The solutions which are defined for NR (5GC) are also applicable to legacy RATs like E-UTRA / LTE, the corresponding CN entities needs to be replaced by LTE entities (for e.g., AMF with MME, g-nodeB (gNB) with e-nodeB (eNB), UDM with HSS etc.), but principles of the solution remain same.

[0238] The Network used in this embodiment is explained using any 5G Core Network Function (for e.g., AMF). However, the network could be any 5G / EUTRAN Core Network Entities like AMF / SMF / MME / UPF or the Network could be any 5G / EUTRAN RAN Entity like eNB or gNB or NG-RAN etc.

[0239] The messages used or indicated in this embodiment are shown as an example. The messages could be any signalling messages between UE and the Network Functions / Entities or between different Network functions / entities.

[0240] The terms camp and register are used interchangeably and have the same meaning.

[0241] The terms wait timer, DisCo wait timer, Discontinuous Coverage wait timer, Random timer, Random wait timer, DCW Timer, Maximum Time Offset, discontinuous coverage maximum time offset is all used interchangeably and have the same meaning.

[0242] The terms wait range, Disco Wait Range, Discontinuous Coverage Wait Range, DCW Range, Discontinuous Wait Range, Disco Wait Range are all used interchangeably and have the same meaning.

[0243] The term area as used in this embodiment may refer to any of cell / cell ID, TAC / TAI, PLMN, MCC / MNC, Latitude / longitude, any CAG / CAG identifier or any geographical location / coordinate.

[0244] For the list of possible NAS messages please refer to 3GPP TS 24.501 or 3GPP TS 24.301, for list of AS messages please refer to 3GPP TS 38.331 or 3GPP TS 36.331.

[0245] Figure 1a illustrates a sequence diagram showing a scenario when a user equipment (UE) has to transmit user data related to an exceptional event in the discontinuous coverage, according to the existing arts.

[0246] In a scenario, the UE 102 does not send (or transmit) a mobile originated (MO) exception data to the network, or even the UE 102 performs any NAS procedure related to MO exception data, when the UE 102 is in discontinuous coverage.

[0247] In step 110, the access & mobility management function (AMF) or any other network entity determines the discontinuous coverage maximum time offset to the UE 102 via the registration procedure, the UE configuration update procedure or any other NAS signalling message.

[0248] In step 112, the UE 102 enters discontinuous coverage and starts to search for coverage again when the UE 102 exits the discontinuous coverage. That is, the UE 102 finds the coverage again optionally of the same PLMN or RAT (optionally also same access type) which configured the discontinuous coverage maximum time offset. The UE 102 starts the discontinuous coverage maximum time offset timer based on the discontinuous coverage maximum time offset provided earlier.

[0249] In step 114, the UE 102 has the MO exception data to be sent to the network (NW) or has to perform some NAS procedure related to the MO exception data.

[0250] In step 116, when discontinuous coverage maximum time offset is running, the UE 102 does not send (or transmit) any MO exception data and does not perform any NAS procedure with respect to the MO exception data to the network.

[0251] Not sending (or transmitting) MO exception data can have serious negative impact on sending real time critical application data to the network, which can impact application services. The critical data can be data related to sensors sensing and relaying critical safety or measurement information.

[0252]

[0253] Figure 1b illustrates a sequence diagram showing a scenario when the UE has to transmit a high priority data in the discontinuous coverage, according to the existing arts.

[0254] The UE 102 does not send (or transmit) the high priority data to the network or even performs any NAS procedure related to sending (or transmitting) the high priority data, when the UE 102 is in the discontinuous coverage.

[0255] In step 120, the AMF or any other network entity 106 determines the discontinuous coverage maximum time offset to the UE 102 via the registration procedure or the UE configuration update procedure or any other NAS signalling message.

[0256] In step 122, the UE 102 enters the discontinuous coverage and starts to search for coverage again when the UE 102 exits the discontinuous coverage. That is, the UE 102 finds the coverage again optionally of the same PLMN / RAT (optionally, also the same access type) which configured the discontinuous coverage maximum time offset. The UE 102 starts the discontinuous coverage maximum time offset timer based on the discontinuous coverage maximum time offset provided earlier.

[0257] In step 124, the UE has the high priority data to be sent to the network entity 106 or has to perform some NAS procedure related to the UE 102 having high priority access.

[0258] In step 126, when the discontinuous coverage maximum time offset is running, the UE 102 does not send any high priority data to the network. Similar problem exists in step 126, the UE 102 does not perform the registration procedure, when the UE 102 has to send data protocol data unit　(PDU) or perform a NAS procedure, and the UE 102 is configured for high priority access or is configured with access identity 11 - 15 (AC 11-15).

[0259] The UE 102 does not perform the registration procedure for the high priority access and the UE 102 can have serious negative impact on sending real time critical application data to the network, which can impact the services. For example, the data can be data related to sensors sensing and relaying critical safety or measurement information. Similarly, in an example scenario, if the UE 102 has to setup a PDN in evolved packet system (EPS) or a PDU in 5G system (5GS), to send (or transmit) high priority data or some data which has been identified for access identity 11 to 15, the UE 102 has to wait till expiry of the discontinuous coverage maximum time offset timer, before the UE 102 can send such data to the network.

[0260] Hence, there is a need in the art for solutions which will overcome the above-mentioned drawback(s), among others.

[0261] Referring now to the drawings, and more particularly to Figures 2 to 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0262]

[0263] Figure 2a is a block diagram illustrating satellite network for discontinuous coverage maximum time offset timer handling in satellite communication, according to embodiments of the disclosure.

[0264] Figure 2a shows a corresponding example of non-terrestrial network (NTN) architectures with a handheld device or a user equipment (UE) 202 on the earth that communicates via a service link (also referred to a user link) with a platform (satellite 204) in the air or in space. The platform (or satellite 204) may communicate directly with a gateway 206 on earth or at first via IAL (inter aerial link) or ISL (inter satellite link) via other platforms in the air or in space.

[0265] Instead of serving UEs directly via airborne / spaceborne platforms, it is also possible that the Service link is arranged between an airborne / spaceborne platform and a relay node on the earth where the relay node serves UEs. So that the satellite 204 would then be this relay node.

[0266] If the airborne platform has the base station (gNB) 218 on board (regenerative payload), then the gateway 206, at the end of the feeder link, can be a router to the core network 208 which connects to the public network.

[0267] In case of non-geostationary satellite orbit (NGSO), i.e., LEO or MEO, the spaceborne satellite 204 will move around the earth faster than the earth rotation which means that at some point in time the feeder link will need to change to another gateway 206 and also that for service continuity the NTN terminal will need to be served by a different spaceborne platform. The feeder link between the NTN gateway 206 and the satellite 204 is also called satellite radio interface (SRI).

[0268] In NTN, continuous satellite coverage can be characterized by the fact that Uu interface is available for the UE 202, at a given position for 100% of the time. In NTN, discontinuous satellite coverage (DC) can be characterized by the fact that Uu interface is available for the UE 202, at a given position, less than 100% of the time, due to predictable lack of satellite coverage. Due to discontinuous coverage, the UE 202 may have access to satellite service coverage only at specific time and places. GPS satellites transmit information about their location (current and predicted), timing and "health" via what is known as ephemeris data. The ephemeris data is used by the GPS receivers to estimate location relative to the satellites and the GPS receiver's position on earth. The ephemeris data can also be used to predict future satellite conditions (for a given place and time) providing a tool for planning when (or when not) to schedule GPS data collection.

[0269]

[0270] Figure 2b is a block diagram illustrating a schematic overview of a wireless network for timer handling in satellite communication, according to the embodiments of the disclosure.

[0271] The wireless network 200 can be, for example, but not limited to a fourth-generation wireless network, a fifth-generation wireless network, open radio access network (ORAN), a 6G network or the like. The wireless network 200 includes one or more UEs 202 and one or more network entities (NE) 218. The network entity 218 may be a PLMN or an SNPN. The UE (102) may be, for example, but not limited to a laptop, a smart phone, a desktop computer, a notebook, a device-to-device (D2D) device, a vehicle to everything (V2X) device, a foldable phone, a smart TV, a tablet, a television, a connected car, an immersive device, an internet of things (IOT) device, or any other device that can communicate using the wireless network.

[0272] In an embodiment herein, the UE 202 comprises a processor 210, an exceptional event data controller 212A, a transceiver 216, and a memory 214. In an embodiment herein, the exceptional event data controller 212A is a part of the processor 210, where the exceptional event data controller 212A communicates with the network entity 218 through the transceiver 216. In another embodiment herein the exceptional event data controller 212A is outside the processor 210 but the exceptional event data controller 212A is in communication with the processor 210, where the exceptional event data controller 212A communicates with the network entity 218 through the transceiver 216. In another embodiment herein, the exceptional event data controller 212A is outside the processor 210, and the exceptional event data controller 212A works separately from the processor 210, where the exceptional event data controller 212A communicates with the network entity 218 through the transceiver 216.

[0273] In an embodiment herein, the memory 216 is configured to store instructions to be executed by the processor 210. The memory 216 can include non-volatile storage elements. Examples of such non-volatile storage elements may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. In addition, the memory 216 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 is non-movable. In some examples, the memory 216 is configured to store 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).

[0274] The processor 210 may include one or a plurality of processors. 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 210 may include multiple cores and is configured to execute the instructions stored in the memory 216.

[0275] In an embodiment, the transceiver 214 includes an electronic circuit specific to a standard that enables wired or wireless communication. The transceiver 214 is configured to communicate internally between internal hardware components of the UE 202 and with external devices via one or more networks.

[0276] In an embodiment herein, the wireless network 200 may include, but is not limited to, a satellite communication network 220 in the coverage area of the UE 202. The network entity 218 may be connected to the satellite 204 that acts as the gateway 206 for the UE 202 to connect with the 5G core (5GC) network 208. The 5G core (5GC) network 208 is further connected wirelessly with a data network 222.

[0277] In an embodiment herein, in satellite communication, since satellites 204 are not static and continue to orbit the earth in low or medium or geo-synchronous earth orbits, a satellite coverage is never static. The UE 202 accessing 4G or 5G core network via the satellite will lose coverage when the satellite 204 moves away, in its orbit, and provides coverage over a new geographical area. Based on satellite coverage and location information both the UE 202 and the core network 208 can calculate an upcoming unavailability period of the UE 202 or the satellite 204. The UE 202 can indicate to the network that the UE 202 wants to enter such unavailability period by performing specific NAS procedures. Typically, in 4G, such the NAS procedure includes a tracking area update (TAU) and in case of 5G, the NAS procedure includes a registration procedure. The discontinuous coverage is a concept where the network coverage is available to the UE 202 in a discontinuous fashion because of the kind of deployment of the network radio or the RAN. Providing cellular network via satellite coverage to the users is one such example.

[0278] In an embodiment herein, the UE 202 can perform the NAS procedure to indicate to the core network 208 that the UE 202 wants to enter or exit unavailability period. When the lot of devices or the UE 202 in a particular area enter or exit unavailability period at the same time, the lot of UEs can cause congestion in the core network 218. To avoid such congestions, the network provides a "discontinuous coverage maximum time offset" to every UE, during NAS procedures. Before entering a NAS procedure for entering unavailability, every UE will wait for a random time greater than zero and smaller than "discontinuous coverage maximum time offset" timer before the UE 202 can trigger the NAS procedure with network. Similarly, when the UE 202 exits unavailability period, the UE 202 waits for a random time greater than zero and smaller than "discontinuous coverage maximum time offset" timer before triggering the NAS procedure with the network. A discontinuous coverage maximum time offset mechanism allows triggering of NAS procedures from different UEs 202 at different points of time and avoids congestion in the network. Although there are some exceptions for some procedures, when the UE 202 is running the timer, and the UE is expecting to enter back in coverage / exit unavailability.

[0279] In an embodiment herein, when the discontinuous coverage maximum time offset timer is running in the UE 202, then ideally the UE 202 has already come back to the satellite network 220 coverage again. But the UE 202 may wait till discontinuous coverage maximum time offset timer expiry to ensure not all UEs 202 are trying to access the network at the same time to indicate that they are back from coverage.

[0280] As per 3GPP TS 24.301, the UE 202 shall not initiate any signalling when the "discontinuous coverage maximum time offset" timer is running in the UE 202. However, there can be specific cases or procedures in the UE 202, which should not be delayed, and should be initiated immediately, even when the above timer is running in the UE 202. These are procedures or cases which need to exempt from being delayed, due to "discontinuous coverage maximum time offset" running in the UE 202.

[0281] In an embodiment herein, the UE 202 may receive a request through the exceptional event data controller 212A to transmit the user data related to the exceptional event. The exceptional event may include a mobile originate (MO) exceptional data. The request may include at least one information regarding at least one of:

[0282] a) a paging message;

[0283] b) a pending emergency services;

[0284] c) establishing an emergency PDN connection;

[0285] d) performing emergency services fallback procedure;

[0286] e) UE enters a new tracking area;

[0287] f) UE is allowed to use exception data reporting (see the ExceptionDataReportingAllowed leaf of the NAS configuration MO in 3GPP TS 24.368 or the USIM file EFNASCONFIG in 3GPP TS 31.102) and the UE has to transmit user data related to an exceptional event;

[0288] g) UE is a MUSIM UE and needs to request an IMSI offset value as specified in clause 5.5.3.2.2; or

[0289] h) UE is a UE configured to use AC 11 - 15 in selected PLMN.

[0290] In an embodiment herein, the UE 202 may determine through the exceptional event data controller 212A that the UE 202 has to send "MO exception data" to the network through the NAS signalling as the UE receives a request to send MO exception data while a discontinuous maximum time offset timer is running in the UE 202. The MO exception data or Mobile originated exception data is a set of data sent from application devices to the network. This kind of data deviates from the norms of regular data and needs special attention, for example exceptions made on decisions whether such data can or cannot be sent to the network, in cases of congestion for example. Examples of MO exception data in IoT can typically be sensor data of critical nature, for example critical errors, critical alerts, sensor readings indicating some abnormal and critical conditions for example fire etc. MO exception data plays a critical role in critical applications in real time communications, using which critical information can be sent to the network with high priority. For example, the MO exception data is used in IoT or handheld devices. The cause names in this embodiment are for illustration purposes, and the causes can have any name. The non-access stratum (NAS) messages and access stratum (AS) messages described in this embodiment is only for illustration purposes; it can be any NAS or AS messages as per defined protocol between UE 202 and AMF / MME or UE 202 and gNB (NG-RAN / any RAN node) / eNB.

[0291] In an embodiment herein, the UE 202 on determining there is a need to send MO exception data to the network while the discontinuous maximum time offset timer is running in the UE 202, the UE 202 may further determine through the exceptional event data controller 212A whether the "UE allowed for exceptional data reporting". When NAS initiates the NAS signalling connection, the UE 202 requests RRC layer of the UE 202 to establish the connection with a valid establishment cause, which indicates the reason for the connection establishment to the network. When the UE 202 is "UE is allowed to use exception data reporting" that means the UE 202 is allowed to establish NAS signalling connection with establishment cause MO-Exception data. The RRC establishment cause can be used by the network to prioritise the connection establishment request from the UE at high load situations in the network.

[0292] In an embodiment herein, the UE 202 may stop timer for "discontinuous coverage maximum time offset" upon determining that the UE 202 is "UE allowed for exceptional data reporting", if the UE 202 has to send "MO exception data", and perform the NAS signalling if required. In general, since the MO exception data is the high priority data, the UE 202 should be given high priority when being sent to the core network 208, and hence the UE 202 has to be exempted from the kind of procedures which can be pended / delayed when the discontinuous coverage maximum time offset timer is running in the UE 202. The MO exception data needs to be prioritized, as this type of data can be indicating some real time critical data which needs to be sent to some server at the earliest. Hence the discontinuous coverage maximum time offset timer needs to be stopped and the UE 202 needs to send out such data to the network 208. Thus, when discontinuous coverage maximum time offset timer is running, the UE 202 shall stop the timer if the UE 202 has to send MO exception data.

[0293] In an embodiment herein, when the timer is running in the UE 202, then the satellite communication is already available in coverage again for the UE 202, the discontinuous coverage maximum time offset timer value is set by the UE 202 to ensure not all UEs are trying to access the network at the same time.

[0294] In an embodiment herein, the discontinuous coverage maximum time offset is determined by the UE 202. The exceptional event data controller 212A of the UE 202 receives the discontinuous coverage maximum time offset from the network entity 218 through at least one of the network registration procedure, the UE configuration update procedure, and any of a NAS signaling message. The exceptional event data controller 212A of the UE 202 initiates the search for network coverage again when the UE exits discontinuous coverage. The exceptional event data controller 212A of the UE 202 starts the timer based on discontinuous coverage maximum time offset provided for the UE 202. In an embodiment herein, the UE 202 may register on the same PLMN or radio access technology (RAT) and optionally also same access type that configured the discontinuous coverage maximum time offset after returning from discontinuous coverage.

[0295] In an example herein, the UE 202 may be accessing PLMN-A, in 4G or 5G access technology, via the satellite communication network 220. The satellite may moves away from current geographical position, and the UE 202 may enter the unavailability period or discontinuous coverage time. The UE 202 may have earlier saved the "discontinuous coverage maximum time offset" value indicated by network. Now for example the UE 202 may expect to enter back in coverage or end unavailability period, at 12 pm, the same day the UE 202 entered the discontinuous time period. On entering the coverage area at 12pm, the UE 202 starts timer with timer value greater than zero and lesser than the "discontinuous coverage maximum time offset". Now the UE determines that the UE 202 has pending "MO exception data" before the timer expiry. The UE 202 stops the timer for "discontinuous coverage maximum time offset" if the UE 202 has to send "MO exception data" and performs the NAS signaling if required. In general, since MO exception data is a high priority data, and MO exception data should be given high priority when being sent to the core network 208, and hence if the UE 202 is having the MP exception data then the UE 202 has to be exempted from the kind of procedures which can be pended / delayed when the discontinuous coverage maximum time offset timer is running in the UE 202. When the discontinuous coverage maximum time offset timer is running in the UE 202, then ideally the UE 202 has already come back to coverage again. However, the UE 202 may wait till discontinuous coverage maximum time offset expiry to ensure not all UEs are trying to access the network at the same time to indicate that they are back from coverage. The MO exception data needs to be prioritized, as the MO exception data can be indicating some real time critical data which needs to be sent to some server at the earliest. Hence the discontinuous coverage maximum time offset timer is stopped and the UE 202 sends out such data to network entity 218. Therefore, when discontinuous coverage maximum time offset timer is running, the UE 202 shall stop the timer if the UE 202 has to send MO exception data.

[0296] Figure 3 illustrates a sequence diagram of a scenario depicting discontinuous coverage maximum time offset timer handling in satellite communication for MO exception data, according to embodiments of the disclosure.

[0297] At step 302, the AMF entity, or any other network entity 218, determines the discontinuous coverage maximum time offset timer to the UE 202 via the Registration procedure or UE Configuration Update procedure or any other NAS signalling message.

[0298] At step 304, the UE 202 enters discontinuous coverage and starts to search for coverage again when the UE 202 exits discontinuous coverage. that is the UE 202 finds the coverage again optionally of the same PLMN or RAT (optionally also same access type) which configured the discontinuous coverage maximum time offset. The UE 202 starts the discontinuous coverage maximum time offset timer based on the discontinuous coverage maximum time offset provided earlier.

[0299] At step 306, the UE 202 has the MO exception data or the high priority data to be sent to the network entity 218, or has some pending NAS procedure which is related to the MO exception data.

[0300] At step 308, when discontinuous coverage maximum time offset timer is running and the UE 202 has to send the MO exception data or the high priority data, or the UE 202 has to perform any NAS procedure related to MO exception data, the UE 202 stops the discontinuous coverage maximum time offset timer. The UE 202 may send the MO exception data to the network 208. The UE 202 may perform a PDU / PDN establishment for the MO exception data. The UE 202 may perform NAS procedure for the MO exception data. The UE 202 may send the high priority data to the core network 208.

[0301]

[0302] In general, since the MO exception data should be given high priority when being sent to the core network, the UE 202 has to be exempted from the kind of services when the discontinuous coverage maximum time offset timer is running in the UE 202. When the discontinuous coverage maximum time offset timer is running in the UE 202, then ideally the UE 202 has already come back to coverage again. But the UE 202 waits till discontinuous coverage maximum time offset expiry to ensure not all the UEs 202 are trying to access the network at the same time to indicate that they are back from coverage. The MO exception data or high priority data needs to be prioritized, as this type of data can be indicating some real time critical data which needs to be sent to some server at the earliest. Hence, the discontinuous coverage maximum time offset timer needs to be stopped and the UE 202 needs to send out such data to core network 208. Therefore, when discontinuous coverage maximum time offset timer is running, the UE 202 shall stop the timer if the UE 202 has to send the MO exception data, wants to setup the PDU or a PDN for the MO exception data, wants to perform any NAS procedure with respect to the MO exception data, or wants to send the high priority data. Optionally, the UE 202 can be configured with the information on whether the UE 202 can send such data as indicated above, when the discontinuous coverage maximum time offset timer is running. This information can be pre-configured in the UE 202 or can be configured in the UE 202 or negotiated with the network entity 218 via the NAS procedures or other 3GPP or non-3GPP specific procedures.

[0303]

[0304] Figure 4 illustrates a flowchart for a method for timer handling in the satellite communication, according to embodiments of the disclosure.

[0305] At step 402, the UE 202 may receive a request to transmit user data related to the exceptional event.

[0306] At step 404, the UE 202 may determine through the exceptional event data controller 212A whether the UE 202 has to send "MO exception data" to the network through NAS signalling as the UE receives a request to send user data related to the exceptional event. The user data related to the exceptional event may be the MO exception data. The MO exception data or the Mobile originated exception data is a set of data sent from application devices to the network. The MO exception data deviates from the norms of regular data and needs special attention, for example exceptions made on decisions whether such data can or cannot be sent to the network, in cases of congestion for example.

[0307] At step 406, the UE 202 may further determine through the exceptional event data controller 212A whether the "UE allowed for exceptional data reporting", on determining that the UE 202 has to send MO exception data. When NAS initiates the NAS signalling connection and the UE requests RRC layer to establish the connection with a valid establishment cause, which indicates the reason for the connection establishment to the network. When a UE 202 is "UE is allowed to use exception data reporting" that means the UE 202 is allowed to establish NAS signalling connection with establishment cause MO-Exception data.

[0308] At step 408, the UE 202 may stop timer for the "discontinuous coverage maximum time offset" upon determining that the UE 202 is "UE allowed for exceptional data reporting", if the UE 202 has to send "MO exception data". At step 410, the UE 202 may initiate NAS signalling to establish a PDU session establishment for the MO exception data and may send the MO exception data to the core network 208.

[0309] The various actions in method 400 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in Figure 4 may be omitted.

[0310]

[0311] Figure 5 is a block diagram illustrating a schematic overview of the wireless network for timer handling in the satellite communication, according to the embodiments of the disclosure.

[0312] In an embodiment herein, the UE 202 comprises a processor 210, a high priority data controller 212B, a transceiver 214, and a memory 216. In an embodiment herein, the high priority data controller 212B is a part of the processor 210, where the controller 212A communicates with the network entity 218 through the transceiver 216. In an embodiment herein the high priority data controller 212B is outside the processor 210 but is in communication with the processor 210, where the high priority data controller 212B communicates with the network entity 218 through the transceiver 216. In an embodiment herein the high priority data controller 212B is outside the processor 210, and the high priority data controller 212B works separately from the processor 210, where the high priority data controller 212B communicates with the network entity 218 through the transceiver 216.

[0313] In an embodiment herein, the UE 202 may receive a request through the high priority data controller 212B to transmit user data having high priority or the UE is configured for high priority access. The request may include at least one information regarding at least one of:

[0314] a) a paging message;

[0315] b) a pending emergency services;

[0316] c) establishing an emergency PDN connection;

[0317] d) performing emergency services fallback procedure;

[0318] e) UE enters a new tracking area;

[0319] f) UE is allowed to use exception data reporting (see the ExceptionDataReportingAllowed leaf of the NAS configuration MO in 3GPP TS 24.368 the USIM file EFNASCONFIG in 3GPP TS 31.102) and the UE has to transmit user data related to an exceptional event;

[0320] g) UE is a MUSIM UE and needs to request an IMSI offset value as specified in clause 5.5.3.2.2; or

[0321] h) UE is a UE configured to use AC 11 - 15 in selected PLMN.

[0322] In an embodiment herein, the UE 202 may determine through the high priority data controller 212B whether the UE 202 is the "UE configured to use AC 11 - 15 in selected PLMN", the "UE configured for high priority access in selected PLMN", or the "UE configured for high priority access in selected SNPN" while the discontinuous maximum time offset timer is running in the UE 202. In an embodiment herein, when the UE 202 needs to access the 5GS (when the UE 202 is not operating under specific cases mentioned in 3GPP TS 24.501), the UE 202 first performs access control checks to determine if the access is allowed. The UE 202 can perform access control check for the specific type of access control. To determine the access identities and the access category for a request, the NAS checks the reason for the access, the types of service requested and the profile of the UE including UE configurations, against a set of access identities and access categories defined in 3GPP TS 22.261, namely a) a set of standardized access identities; b) a set of standardized access categories; and c) a set of operator-defined access categories, if available.

[0323] In an embodiment herein, the access identity is a representation of the user or the device (UE 202) that has specific access privileges. Depending on operator's policies, deployment scenarios, subscriber profiles, and available services, a criterion for access control is associated with access identities and access categories. The access identities are used in determining which access attempt should be allowed or blocked when congestion occurs in the network.

[0324] When the UE 202 is configured for access identity 1 (AC 1), the UE is configured for multimedia priority service (MPS).

[0325] When the UE 202 is configured for access identity 2 (AC 2), the UE is configured for mission critical services (MCS).

[0326] The Access identities 11 and 15 (AC 11-15) are valid in HPLMN (if the EHPLMN list is not present or is empty) or EHPLMN (if the EHPLMN list is present). The Access identities 11 and 15 (AC 11-15) are valid if indicated as configured for the UE 202 in the unified access control configuration in the "list of subscriber data" stored in the UE 202 (refer 3GPP TS 23.122), if an entry of "list of subscriber data" is selected, or in the USIM (refer 3GPP TS 31.102), if the PLMN subscription is selected, in the selected SNPN, if a new SNPN is selected, or RSNPN, and the selected SNPN or the RSNPN is the subscribed SNPN. Access identities 12, 13 and 14 (AC 12, AC 13, AC 14) are valid if indicated as configured for the UE in the unified access control configuration in the "list of subscriber data" stored in the UE 202 (refer 3GPP TS 23.122), if an entry of "list of subscriber data" is selected, or in the USIM (refer 3GPP TS 31.102), if the PLMN subscription is selected, in the selected SNPN, if a new SNPN is selected, or RSNPN, and the selected SNPN or the RSNPN in the subscribed SNPN or an non-subscribed SNPN of the same country as the subscribed SNPN if the MCC of the SNPN identity of the subscribed SNPN is not the MCC of value 999.

[0327] In an embodiment herein, the UE 202 configured for the high priority access in selected PLMN or the SNPN, or the UE 202 can be the UE configured with one or more access identities equal to 1, 2, or 11-15 applicable in the selected PLMN or SNPN as specified in 3GPP TS 24.501.

[0328] In an embodiment herein, the UE 202 may stop timer for "discontinuous coverage maximum time offset" upon determining that the UE 202 is the UE 202 configured for high priority access in selected PLMN or the SNPN, or the UE 202 can be a configured with one or more access identities equal to 1, 2, or 11-15 applicable in the selected PLMN or SNPN as specified in 3GPP TS 24.501 and perform NAS signalling if required.

[0329] In an embodiment herein, when the UE 202 is configured for high priority access in a selected PLMN (HPLMN, EHPLMN or VPLMN) or a SNPN (subscribed SNPN or non-subscribed SNPN), the UE is configured with access identity 11 - 15 in the selected PLMN (HPLMN, EHPLMN or VPLMN) or the selected SNPN (subscribed SNPN or non-subscribed SNPN), and the discontinuous coverage maximum time offset timer is running, and if the UE 202 has to send data PDUs or perform a NAS procedure for example to set up the PDN in EPS or set up the PDU in 5GS, the UE 202 shall stop the discontinuous coverage maximum time offset timer. The UE 202 may proceed with the setup of the PDN or the PDU session by initiating NAS signalling. The solution described in Figure 5 is also applicable for the case if the UE configured for high priority access in the selected PLMN (HPLMN, EHPLMN or VPLMN) or the SNPN (subscribed SNPN or non-subscribed SNPN), or configured with access identity 11 - 15 in the selected PLMN (HPLMN, EHPLMN or VPLMN) or the selected SNPN (subscribed SNPN or non-subscribed SNPN). When the discontinuous coverage maximum time offset timer is running and the UE has to perform some NAS procedure, the UE 202 shall stop the discontinuous coverage maximum time offset timer and proceed with sending the data PDUs or the required NAS procedure in case of the UE 202 needs to send high priority data.

[0330] In an embodiment herein, the UE 202 configured for high priority access in selected PLMN or the UE 202 configured for high priority access in selected SNPN is the UE 202 configured with at least one access identity 1, access identity 2, and access identity 11, access identity 12, access identity 13, access identity 14, and access identity 15, and the access class is applicable in the selected PLMN or the selected SNPN. The UE 202 configured to use AC 11 - 15 in selected PLMN is the UE that is configured with at least one access identity 11, access identity 12, access identity 13, access identity 14, and access identity 15.and the access class is applicable in the selected PLMN. For the access identity 1, the UE 202 is configured for multimedia priority service (MPS). For the access identity 2, the UE 202 is configured for mission critical services (MCS) and access identities 11 and access identity 15 are valid in an HPLMN if an EHPLMN list is not present or is empty and the EHPLMN if the EHPLMN list is present.

[0331] In an embodiment herein, the UE 202 determines, whether at least one condition is met by the UE 202. The condition may include, but is not limited to: whether the UE 202 is the UE configured for high priority access in selected PLMN, a UE configured for high priority access in selected PLMN, or a UE configured to use AC 11 - 15 in selected PLMN when the discontinuous coverage maximum time offset timer is running in the UE. The UE stops the discontinuous coverage maximum time offset timer and initiates NAS signaling.

[0332] In an embodiment herein, the UE 202 determines whether at least one of a condition is met. The condition includes, but is not limited to whether the access identity 12, access identity 13 and access identity 14 is configured for the UE 202 in a unified access control configuration in the "list of subscriber data" stored in a mobile equipment (ME) and an entry of "list of subscriber data" is selected, whether a PLMN subscription is selected in a USIM, whether a new SNPN or an RSNPN is selected in a selected SNPN network, the RSNPN is the subscribed SNPN and the selected SNPN or the RSNPN in the subscribed SNPN or an non-subscribed SNPN of the same country, and the subscribed SNPN if a Mobile Country Code (MCC) of the SNPN identity of the subscribed SNPN is not the MCC of value 999. The UE 202 indicates the access identity 12, access identity 13, and access identity 14 are valid on determining the at least one condition is met.

[0333] In an embodiment herein, when the timer is running in the UE 202, then the satellite communication is already available in coverage again for the UE 202, the discontinuous coverage maximum time offset timer value is set by the UE 202 to ensure not all UEs are trying to access the network at the same time.

[0334] In an embodiment herein, the discontinuous coverage maximum time offset is determined by the UE 202. The UE 202 receives the discontinuous coverage maximum time offset the from network entity through at least one of the network registration procedure, the UE configuration update procedure, or any of the NAS signaling message. The UE 202 initiates the search for network coverage again when the UE exits 202 discontinuous coverage. The UE 202 starts the timer based on discontinuous coverage maximum time offset provided for the UE 202. In an embodiment herein, the UE 202 may register on the same PLMN or radio access technology (RAT) and optionally also same access type that configured the discontinuous coverage maximum time offset after returning from discontinuous coverage.

[0335] In an example herein, the UE 202 is accessing PLMN-A, in 4G or 5G access technology, via the satellite communication network 220. The satellite 204 may move away from the current geographical position, and the UE 202 enters in unavailability period or the discontinuous coverage time. The UE 202 may have earlier saved the "discontinuous coverage maximum time offset" value indicated by network. For example, the UE 202 may expect to enter back in coverage or end unavailability period at 12 pm, the same day when the UE 202 entered the discontinuous coverage. The UE 202 starts the timer on entering back to coverage at 12pm, with the timer value greater than and lesser than "discontinuous coverage maximum time offset". The UE 202 may either be configured as the UE 202 configured to use AC 11 - 15 in selected PLMN or the UE 202 configured for high priority access in selected PLMN, and the UE 202 has to perform NAS signaling or send out high priority data to the network. The UE 202 may stop the "discontinuous coverage maximum time offset" timer if running, for any signaling if the UE 202 is the UE configured to use AC 11 - 15 in selected PLMN or the UE configured for high priority access in selected PLMN. In general, UEs 202 which are configured with access classes 11-15, are considered as high priority devices. And hence, any data or signaling messages from such UEs 202 have to be exempted from the kind of procedures which can be pended / delayed when the discontinuous coverage maximum time offset timer is running in the UE 202. When the discontinuous coverage maximum time offset timer is running in the UE 202, then ideally the UE 202 has already come back to coverage again. However, the UEs 202 which are configured for access class 11-15 are higher priority devices, and any data and signaling from such high priority devices need to be prioritized. Hence, the high priority data controller 212B stops the discontinuous coverage maximum time offset timer and the high priority data controller 212B sends out data packets or perform signaling. Therefore, when discontinuous coverage maximum time offset timer is running, the UE 202 shall stop the timer if the UE 202 is the UE 202 configured to use AC 11 - 15 in selected PLMN or the UE 202 configured for high priority access in selected PLMN and has to send data packets or signaling messages to the network.

[0336]

[0337] Figure 6 illustrates a sequence diagram of a scenario for discontinuous coverage maximum time offset timer handling in satellite communication for a UE configured for high priority access, according to embodiments of the disclosure.

[0338] At step 602, the AMF or any other network entity 218, determines the discontinuous coverage maximum time offset to the UE 202 via the registration procedure or UE configuration update procedure or any other NAS signalling message.

[0339] At step 604, the UE 202 enters discontinuous coverage and starts to search for coverage again when the UE 202 exits discontinuous coverage i.e., when the UE 202 finds the coverage again optionally of the same PLMN / RAT (optionally also same access type) which configured the discontinuous coverage maximum time offset. The UE 202 starts the discontinuous coverage maximum time offset timer based on the discontinuous coverage maximum time offset provided by the network entity 218.

[0340] At step 606, the UE 202 has high priority data to be sent to the core network 208, or the UE 202 configured for high priority access in selected PLMN or the SNPN, or the UE 202 can be a UE configured with one or more access identities equal to 1, 2, or 11-15 applicable in the selected PLMN or SNPN.

[0341] At step 608, when discontinuous coverage maximum time offset timer is running and the UE has to send high priority data, or the UE 202 configured for high priority access in selected PLMN or the SNPN, or the UE 202 can be a UE configured with one or more access identities equal to 1, 2, or 11-15 applicable in the selected PLMN or SNPN, the UE stops the discontinuous coverage maximum time offset timer and sends the high priority data, or performs PDU / PDN establishment for the high priority data or performs NAS procedure for the high priority data or sends high priority data to the NW.

[0342]

[0343] Figure 7 illustrates a flowchart for a method for timer handling in the satellite communication, according to embodiments of the disclosure.

[0344] At step 702, the UE 202 may receive a request through the high priority data controller 212B to transmit user data having high priority or the UE is configured for high priority access.

[0345] At step 704, the UE 202 determines whether the UE 202 is the "UE configured to use AC 11 - 15 in selected PLMN", the "UE configured for high priority access in selected PLMN", or the "UE configured for high priority access in selected SNPN" while the discontinuous maximum time offset timer is running in the UE 202.

[0346] At step 706, the UE 202 stops the timer if the UE 202 determines that the UE 202 is the "UE configured to use AC 11 - 15 in selected PLMN", the "UE configured for high priority access in selected PLMN", or the "UE configured for high priority access in selected SNPN" while the discontinuous maximum time offset timer is running in the UE 202.

[0347] At step 708, the UE 202 initiates the NAS signaling procedure to establish a PDU or PDN session to transmit user data.

[0348]

[0349] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The elements include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[0350] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The elements include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[0351] The embodiments disclosed herein describe a systems and methods for timer handling in satellite communication. Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in e.g., Very high-speed integrated circuit Hardware Description Language (VHDL) another programming language, or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means which could be e.g., hardware means like e.g., an ASIC, or a combination of hardware and software means, e.g., an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, e.g., using a plurality of CPUs.

[0352] 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 should and 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 embodiments and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practised with modification within the scope of the embodiments as described herein.

Claims

1.A method performed by a terminal in a wireless communication system, the method comprising:receiving, from a core network, configuration information on a timer for restricting an initiation of a non-stratum access (NAS) signaling procedure;starting the timer, based on a return of the terminal into a coverage provided by the core network via a satellite;determining whether a condition is satisfied, the condition including that the terminal is required to transmit user data having high priority;in case that the condition is satisfied, stopping the timer; andinitiating the NAS signaling procedure for transmitting the user data.2.The method of claim 1,wherein the condition further includes that the terminal is allowed to use an exception data reporting, andwherein the user data is related to an exceptional event.3.The method of claim 2, further comprising:obtaining, from a higher layer, a request to transmit the user data related to the exceptional event,wherein the exceptional event includes a transmission of a mobile originate (MO) exceptional data.4.The method of claim 1,wherein the terminal is configured for the high priority access to the core network, andwherein the terminal is configured with at least one of access classes (AC) 11, 12, 13, 14, and 15.5.The method of claim 1,wherein the timer is a discontinuous coverage maximum time offset timer, andwherein a value of the timer is set to a random value up to a time offset indicated by the configuration information.6.The method of claim 1, further comprising:receiving, from the core network, information on an unavailability period,wherein the unavailability period indicates a period during which terminal is unable to access to the core network via the satellite due to a discontinuous coverage.7.A terminal in a wireless communication system, the terminal comprising:a transceiver; anda processor coupled with the transceiver and configured to:receive, from a core network, configuration information on a timer for restricting an initiation of a non-stratum access (NAS) signaling procedure,start the timer, based on a return of the terminal into a coverage provided by the core network via a satellite,determine whether a condition is satisfied, the condition including that the terminal is required to transmit user data having high priority,in case that the condition is satisfied, stop the timer, andinitiate the NAS signaling procedure for transmitting the user data.8.The terminal of claim 7,wherein the condition further includes that the terminal is allowed to use an exception data reporting, andwherein the user data is related to an exceptional event.9.The terminal of claim 8,wherein the processor is further configured to obtain, from a higher layer, a request to transmit the user data related to the exceptional event, andwherein the exceptional event includes a transmission of a mobile originate (MO) exceptional data.10.The terminal of claim 7,wherein the terminal is configured for the high priority access to the core network, andwherein the terminal is configured with at least one of access classes (AC) 11, 12, 13, 14, and 15.11.The terminal of claim 7,wherein the timer is a discontinuous coverage maximum time offset timer, andwherein a value of the timer is set to a random value up to a time offset indicated by the configuration information.12.The terminal of claim 7,wherein the processor is further configured to receive, from the core network, information on an unavailability period, andwherein the unavailability period indicates a period during which terminal is unable to access to the core network via the satellite due to a discontinuous coverage.

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