Handling power savings in UEs during discontinuous coverage of satellite access networks

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A user equipment (UE) indicates a registration request message including an unavailability type to an access and mobility management function (AMF), receives a registration acceptance message including an unavailability period duration from the AMF, where the unavailability period duration is determined by the AMF based on the unavailability type, and performs at least one action during the unavailability period duration.

Description

Technical Field

[0001] Embodiments disclosed herein relate generally to the field of satellite access networks, and more particularly to a method and a satellite access network for handling power conservation in a user equipment (UE) during discontinuous coverage of a satellite access network. Background Art

[0002] 5G mobile communication technology defines a wide frequency band, enabling high transmission rates and new services, and can be implemented not only in "sub-6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands, known as millimeter waves (mmWave), including 28 GHz and 39 GHz. Furthermore, consideration has been given to implementing 6G mobile communication technology (referred to as a "super 5G system") in the terahertz frequency band (e.g., the 95 GHz to 3 THz band) in order to achieve transmission rates fifty times faster than 5G mobile communication technology and ultra-low latency one-tenth that of 5G mobile communication technology.

[0003] At the start of the development of 5G mobile communication technology, in order to support services related to enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC) and massive machine-type communications (mMTC) and meet the performance requirements associated therewith, standardization has been underway on: beamforming and massive MIMO for mitigating radio wave path loss in mmWave and increasing radio wave transmission distance, parameter sets supporting dynamic operation for efficient utilization of mmWave resources and time slot formats (e.g., operation of multiple subcarrier spacings); initial access technology for supporting multi-beam transmission and broadband; definition and operation of BWP (bandwidth part); new channel coding methods such as LDPC (low-density parity-check) codes for large-volume data transmission and polar codes for high-reliability transmission of control information; L2 preprocessing; and network slicing for providing dedicated networks dedicated to specific services.

[0004] Currently, in view of the services to be supported by 5G mobile communication technology, discussions are underway on improvements and performance enhancements to initial 5G mobile communication technology, and physical layer standardization is underway on technologies such as V2X (Vehicle-to-Everything) for assisting autonomous vehicles in driving determination based on information about the location and status of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) for system operation in compliance with various regulatory requirements in unlicensed frequency bands, NR UE power saving, non-terrestrial network (NTN) as UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is unavailable, and positioning.

[0005] In addition, standardization is underway for air interface architecture / protocols related to technologies such as the Industrial Internet of Things (IIoT) for supporting new services through interworking and integration with other industries, IAB (Integrated Access and Backhaul) for providing nodes for network service area expansion by supporting wireless backhaul links and access links in an integrated manner, mobility enhancements including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access (NR two-step RACH) for simplifying the random access procedure. Standardization is also underway for system architectures and services such as a 5G baseline architecture (e.g., a service-based architecture or service-based interface) for combining network function virtualization (NFV) and software-defined networking (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0006] With the commercialization of 5G mobile communication systems, the number of connected devices, which has been growing exponentially, will be connected to the communication network. Accordingly, it is expected that enhanced functionality and performance of 5G mobile communication systems and the integrated operation of connected devices will become necessary. To this end, new research is being planned related to effectively supporting extended reality (XR) such as AR (augmented reality), VR (virtual reality), and MR (mixed reality); improving 5G performance and reducing complexity by leveraging artificial intelligence (AI) and machine learning (ML); supporting AI services; supporting metaverse services; and drone communications.

[0007] Moreover, such development of 5G mobile communication systems will serve not only as a foundation for developing new waveforms for providing coverage of the terahertz band for 6G mobile communication technology, such as multi-antenna transmission technologies such as full-dimensional MIMO (FD-MIMO) array antennas and massive antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, and high-dimensional spatial multiplexing technologies utilizing OAM (orbital angular momentum) and RIS (reconfigurable smart surfaces), but also as a foundation for developing full-duplex technologies for improving the frequency efficiency of 6G mobile communication technology and improving system networks, AI-based communication technologies for achieving system optimization by leveraging satellites and AI (artificial intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technologies for implementing services with a complexity that exceeds the limits of UE operating capabilities by utilizing ultra-high-performance communication and computing resources. Summary of the Invention

[0008] Technical Solution

[0009] In a first aspect of the present disclosure, a method performed by a user equipment (UE) is provided, the method comprising: indicating a registration request message including an unavailability type to an access and mobility management function (AMF); receiving a registration accept message including an unavailability period duration from the AMF, wherein the unavailability period duration is determined by the AMF based on the unavailability type; and performing at least one action during the unavailability period duration.

[0010] In a second aspect of the present disclosure, a user equipment (UE) is provided, comprising: a transceiver; and at least one processor coupled to the transceiver, configured to: indicate a registration request message including an unavailability type to an access and mobility management function (AMF), receive a registration accept message including an unavailability period duration from the AMF, wherein the unavailability period duration is determined by the AMF based on the unavailability type, and perform at least one action during the unavailability period duration.

[0011] In a third aspect of the present disclosure, an access and mobility management function (AMF) is provided herein, comprising: a transceiver; and at least one processor coupled to the transceiver, configured to: obtain a registration request message including an unavailability type, determine an unavailability period duration based on the unavailability type, and transmit a registration accept message including the unavailability period duration to a user equipment (UE). BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The method and satellite access network are shown in the accompanying drawings, and the same reference numerals represent corresponding parts throughout the drawings. The embodiments of the present invention will be better understood from the following description with reference to the accompanying drawings, in which:

[0013] Figure 1 A block diagram illustrating a satellite access network for satellite communications according to an embodiment of the present disclosure;

[0014] Figure 2 A sequence diagram illustrating that a UE and a network are out of synchronization, resulting in paging loss / loss of service for the UE, according to an embodiment of the present disclosure is shown;

[0015] Figure 3 A sequence diagram illustrating a UE performing a cell search according to an embodiment of the present disclosure;

[0016] Figure 4 A sequence diagram illustrating UE and AMF entities for handling power saving in UE during discontinuous coverage of a satellite access network according to an embodiment of the present disclosure;

[0017] Figure 5 A sequence diagram illustrating a UE determining that an unreachable period acceptance timer is running according to an embodiment of the present disclosure;

[0018] Figure 6 A block diagram illustrating a satellite access network for handling power conservation in a UE during discontinuous coverage of the satellite access network according to an embodiment of the present disclosure;

[0019] Figure 7 illustrates various hardware components of a UE according to an embodiment of the present disclosure;

[0020] Figure 8 illustrates various hardware components of a network device according to an embodiment of the present disclosure;

[0021] Figure 9 is a flow chart illustrating a method implemented by a UE for handling power saving in a UE during discontinuous coverage of a satellite access network according to an embodiment of the present disclosure; and

[0022] Figure 10 is a flow chart illustrating a method implemented by a network device for handling power saving in a UE during discontinuous coverage of a satellite access network according to an embodiment of the present disclosure.

[0023] It will be noted that, to the extent possible, identical reference numerals have been used to denote identical elements in the accompanying drawings. Furthermore, one of ordinary skill in the art will appreciate that the elements in the accompanying drawings are illustrated for simplicity and may not necessarily be drawn to scale. For example, the dimensions of some elements in the accompanying drawings may be exaggerated relative to other elements to help improve understanding of various aspects of the present invention. Furthermore, one or more elements may have been represented in the accompanying drawings by conventional symbols, and the accompanying drawings may only show those specific details relevant to understanding embodiments of the present invention, so as to avoid confusing the accompanying drawings with details that would be readily understood by one of ordinary skill in the art having the benefit of the description herein. DETAILED DESCRIPTION

[0024] Various embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. In the following description, only specific details such as detailed configuration and components are provided to facilitate a comprehensive understanding of these embodiments of the present disclosure. Therefore, it will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope of the present disclosure. In addition, for the sake of clarity and conciseness, descriptions of well-known functions and structures have been omitted.

[0025] Furthermore, the embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0026] As used herein, the term "or" refers to a non-exclusive or unless otherwise indicated. The examples used herein are intended only to facilitate understanding of how the embodiments herein may be practiced and to further enable those skilled in the art to practice the embodiments herein. Therefore, the examples should not be construed as limiting the scope of the embodiments herein.

[0027] As is conventional in the art, embodiments may be described and illustrated in terms of blocks that perform one or more of the described functions. These blocks, which may be referred to herein as managers, units, modules, hardware components, and the like, are physically implemented by analog and / or digital circuitry (such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hard-wired circuitry, and the like) and may optionally be driven by firmware and software. The circuitry may, for example, be embodied in one or more semiconductor chips or on a substrate support such as a printed circuit board. The circuitry comprising 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 that performs some of the block's functions and a processor that performs other functions of the block. Each block of an embodiment may be physically separated into two or more interacting and discrete blocks without departing from the scope of this disclosure. Similarly, the blocks of an embodiment may be physically combined into more complex blocks without departing from the scope of this disclosure.

[0028] The 5G system supports service continuity between New Radio (NR) terrestrial access networks and NR satellite access networks, either owned by the same operator or by two different operators under an agreement. The non-terrestrial network (NTN) and the terrestrial network (TN) can operate in two different frequency bands (e.g., FR1 vs. FR2) or in the same frequency band (e.g., FR1 or FR2). The terms satellite 3GPP access, satellite access, satellite access network, NR satellite access network, satellite next-generation radio access network (NG-RAN) access technology, and NR satellite access are used interchangeably and have the same meaning. The methods, problems, and solutions disclosed in the embodiments are explained using NR satellite access or satellite NG-RAN access technology as examples and are not limited to or restricted to NR satellite access alone. However, the solutions proposed in these embodiments are also applicable to satellite-based Evolved Universal Mobile Telecommunications Access Network (E-UTRAN) access technology, NB (Narrow Band)-S1 mode or WB (Wide Band)-S1 mode via satellite E-UTRAN access, and / or NB-IoT (Narrow Band Internet of Things) or WB-IoT (Wide Band Internet of Things) satellite access / architecture. The solutions defined for NR (5GC) are also applicable to legacy radio access technologies (RATs) such as E-UTRA / LTE. The corresponding CN entities need to be replaced by Long Term Evolution (LTE) entities, for example, the Access and Mobility Management Function (AMF) entity is replaced by the Mobility Management Entity (MME), the Next Generation Node B (gnodeB) is replaced by the Evolved Node B (e-nodeB), and the HSS replaces the UDM. However, the principles of the solutions remain the same. An example list of NAS messages may be, but is 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 the like.

[0029] The network used in the embodiments is explained using any 5G core network function (e.g., an AMF entity). However, the network may be any 5G / EUTRAN core network entity, such as an AMF entity, SMF entity, MME, or UPF entity, or any 5G / EUTRAN RAN entity, such as an eNodeB (eNB), gNodeB (gNB), or NG-RAN. The messages used or indicated in the embodiments are shown as examples. The messages may be any signaling messages between a UE and a network function / entity, or between different network functions / entities. The terms area / location / geographic area used in the embodiments may refer to any of a cell / cell ID, a tracking area code (TAC) / tracking area identity (TAI), a public land mobile network (PLMN), a mobile country code (MCC) / mobile network code (MNC), latitude / longitude, a CAG cell, or any geographic location / coordinates.

[0030] The following are the abbreviations used in the patent disclosure:

[0031] 1. NTN - Non-Terrestrial Network

[0032] 2. TER: Ground

[0033] 3. SAT: Satellite

[0034] 4. TN - Terrestrial Network

[0035] 5. UE - User Equipment

[0036] 6. eNB - Evolved Node B

[0037] 7. gNB - Next Generation Node B

[0038] 8. EPC - Evolved Packet Core

[0039] 9. 5GC - 5G Core

[0040] 10.DC-Discontinuous Coverage

[0041] 11. NW-Network

[0042] 12. E-UTRA - Evolved Universal Mobile Telecommunications Access

[0043] 13. NG-RAN - Next Generation Radio Access Network

[0044] 14. EUTRAN - Evolved Universal Mobile Telecommunications Access Network

[0045] 15. HPLMN-Home Public Land Mobile Network

[0046] 16. 3GPP - Third Generation Partnership Project

[0047] 17. Uu - Radio interface between UE and Node B

[0048] 18. TAU - Tracking Area Update

[0049] 19. RAT - Radio Access Technology

[0050] 20. OOS - Out of Service

[0051] 21. AMF Entity - Access and Mobility Management Function Entity

[0052] 22. MME - Mobility Management Entity

[0053] 23. GPS - Global Positioning System

[0054] 24. DRX-Discontinuous Reception

[0055] 25. eDRX-Extended Discontinuous Reception

[0056] 26. DL - Downlink

[0057] 27. UL - Uplink

[0058] 28. QoS - Quality of Service

[0059] 29. ARP-Allocation and Retention Policy

[0060] 30. MICO-Mobile initiated communications only

[0061] 31. MCS-Mission Critical Services

[0062] 32. MPS-Multimedia Priority Service

[0063] 33. ME-Mobile Equipment

[0064] 34. USIM-Universal Subscriber Identity Module

[0065] 35. Uu - Radio interface between UE and Node B

[0066] 36. PLMN-Public Land Mobile Network

[0067] 37. FR-Frequency Range

[0068] 38. AS-Access Layer

[0069] 39. NAS Non-Access Stratum

[0070] 40. Satellite: An artificial object placed in orbit around the Earth or the Moon or another planet for the purpose of collecting information or for communication.

[0071] 41. Satellite constellation: A cluster of satellites placed in orbit around the Earth or the Moon or another planet to gather information or for communications.

[0072] 42. Service User: An individual who has received a priority allocation from a regional / national authority (i.e. a body authorised to issue priority allocations) and who has a subscription with a mobile network operator.

[0073] 43. OS Upgrade: Operating System Upgrade

[0074] 44. SW: Software

[0075] 45. PSM: Power Saving Mode

[0076] The term 5GMM sublayer state in the embodiments is at least one of the following:

[0077] 1) 5GMM-NULL

[0078] 2) 5GMM-DEREGISTERED

[0079] a) 5GMM-DEREGISTERED.NORMAL-SERVICE

[0080] b) 5GMM-DEREGISTERED.LIMITED-SERVICE

[0081] c) 5GMM-DEREGISTERED.ATTEMPTING-REGISTRATION

[0082] d) 5GMM-DEREGISTERED.PLMN-SEARCH

[0083] e) 5GMM-DEREGISTERED.NO-SUPI

[0084] f) 5GMM-DEREGISTERED.NO-CELL-AVAILABLE

[0085] g) 5GMM-DEREGISTERED.eCALL-INACTIVE

[0086] h) 5GMM-DEREGISTERED.INITIAL-REGISTRATION-NEEDED

[0087] 3) 5GMM-REGISTERED-INITIATED

[0088] 4) 5GMM-REGISTERED

[0089] a) 5GMM-REGISTERED.NORMAL-SERVICE

[0090] b) 5GMM-REGISTERED.NON-ALLOWED-SERVICE

[0091] c) 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE

[0092] d) 5GMM-REGISTERED.LIMITED-SERVICE

[0093] e) 5GMM-REGISTERED.PLMN-SEARCH

[0094] f) 5GMM-REGISTERED.NO-CELL-AVAILABLE

[0095] g) 5GMM-REGISTERED.UPDATE-NEEDED

[0096] 5) 5GMM-DEREGISTERED-INITIATED

[0097] 6) 5GMM-SERVICE-REQUEST-INITIATED.

[0098] In an embodiment of the present disclosure, the term EPS Mobility Management (EMM) sublayer state is at least one of the following:

[0099] 1) EMM-NULL

[0100] 2) EMM-DEREGISTERED

[0101] a)EMM-DEREGISTERED.NORMAL-SERVICE

[0102] b) EMM-DEREGISTERED.LIMITED-SERVICE

[0103] c) EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH

[0104] d)EMM-DEREGISTERED.PLMN-SEARCH

[0105] e) EMM-DEREGISTERED.NO-IMSI

[0106] f) EMM - DEREGISTERED.ATTACH - NEEDED

[0107] g) EMM - DEREGISTERED.NO - CELL - AVAILABLE

[0108] h) EMM - DEREGISTERED.eCALL - INACTIVE

[0109] 3) EMM - REGISTERED - INITIATED

[0110] 4) EMM - REGISTERED

[0111] a) EMM - REGISTERED.NORMAL - SERVICE

[0112] b) EMM - REGISTERED.ATTEMPTING - TO - UPDATE

[0113] c) EMM - REGISTERED.LIMITED - SERVICE

[0114] d) EMM - REGISTERED.PLMN - SEARCH

[0115] e) EMM - REGISTERED.UPDATE - NEEDED

[0116] f) EMM - REGISTERED.NO - CELL - AVAILABLE

[0117] g) EMM - REGISTERED.ATTEMPTING - TO - UPDATE - MM

[0118] h) EMM - REGISTERED.IMSI - DETACH - INITIATED

[0119] 5) EMM - DEREGISTERED - INITIATED

[0120] 6) EMM - TRACKING - AREA - UPDATING - INITIATED

[0121] 7) EMM - SERVICE - REQUEST - INITIATED

[0122] The term RAT as defined in the embodiments can be one of the following:

[0123] (1) NG - RAN

[0124] (2) 5G, 4G, 3G, 2G

[0125] (3) EPS, 5GS

[0126] (4) NR

[0127] (5) NR in unlicensed bands

[0128] (6) NR (LEO) satellite access

[0129] (7) NR (MEO) satellite access

[0130] (8) NR (GEO) satellite access

[0131] (9) NR (OTHERSAT) satellite access

[0132] (10) NR RedCap

[0133] (11) E-UTRA

[0134] (12) E-UTRA in unlicensed bands

[0135] (13) NB-IoT

[0136] (14) WB-IoT

[0137] (15) LTE-M

[0138] PLMN selection according to 23.122 in the absence of a registered PLMN (RPLMN): The MS selects and attempts to register on any PLMN / access technology combination, if available and permitted, in the following order:

[0139] 1. Either the HPLMN (if the EHPLMN list does not exist or is empty) or the highest priority EHPLMN available (if the EHPLMN list exists);

[0140] 2. Each PLMN / access technology combination in the "Subscriber Controlled PLMN and Access Technology Selector" data file in the Subscriber Identity Module (SIM) (in order of priority);

[0141] 3. Each PLMN / access technology combination in the "Operator Controlled PLMN and Access Technology Selector" data file in the SIM (in order of priority) or stored in the ME (in order of priority);

[0142] 4. Other PLMN / access technology combinations that receive high-quality signals in random order;

[0143] 5. Other PLMN / access technology combinations in order of decreasing signal quality.

[0144] PLMN selection according to 23.122 with RPLMN: The mobile station (MS) selects and attempts to register on any PLMN / access technology combination in the following order, if available and permitted:

[0145] 1. Either RPLMN or the last registered PLMN;

[0146] 2. Either the HPLMN (if the Equivalent HPLMN (EHPLMN) list does not exist or is empty) or the highest priority EHPLMN available (if the EHPLMN list exists);

[0147] 3. Each PLMN / access technology combination in the "Subscriber Controlled PLMN and Access Technology Selector" data file in the SIM (in order of priority);

[0148] 4. Each PLMN / access technology combination in the "Operator Controlled PLMN and Access Technology Selector" data file in the SIM (in order of priority) or stored in the ME (in order of priority);

[0149] 5. Other PLMN / access technology combinations that receive high-quality signals in random order;

[0150] 6. Other PLMN / access technology combinations in order of decreasing signal quality.

[0151] Generally, 3GPP specifications require UEs to be in discontinuous coverage in satellite scenarios. Due to the continuous mobility of satellites or satellite constellations, UEs may only have coverage at specific times and locations. With discontinuous coverage, UEs can only access satellite service coverage at specific times and locations. In discontinuous coverage in satellite scenarios, due to the continuous mobility of satellites or satellite constellations, UEs are restricted to having coverage only at specific times. While in connected or idle mode, a UE can determine that it has left network coverage based on coverage information or any other information (e.g., satellite ephemeris). When the UE will regain satellite coverage after a specific time, the UE may initiate signaling to the network due to any UL traffic or NAS layer signaling. Similarly, if the network has buffered any downlink data, it may page the UE when it determines that the UE has returned to coverage. If the network determines that the UE has returned to coverage, it also triggers any downlink signaling. A few of the power saving mechanisms / timers / parameters (but not limited to or restricted to these) are Active Time / MICO mode with Active Time, Extended Connected Time / MICO mode with Extended Connected Time, Periodic TAU Timer / Periodic Update Timer, Periodic Registration Timer / Periodic Registration Update Timer and eDRX parameters (such as cycle length).

[0152] For fifth-generation (5G) systems with satellite access, the following requirements apply. In satellite communications, due to the mobile nature of cells, gap durations are expected, where a particular location cannot be served by that satellite because it moves away from that location before another satellite begins covering that area. Since the satellite's ephemeris is known in advance, it is possible to calculate the duration that a particular location will be outside of satellite coverage. Furthermore, a UE at that location will not be able to perform communications with the satellite during the gap period / unavailable duration. With the above in mind, the concept of an unavailable period timer (or unavailable duration or any similar name) is introduced, during which the UE is outside of satellite cell coverage. During this period, the UE may choose to apply power saving measures, etc.

[0153] Furthermore, a UE may become unavailable for a variety of reasons (events), for example, if the UE must undergo a software upgrade or OS upgrade or apply a security patch. Another reason could be because the UE is entering discontinuous coverage. In this example, an OS upgrade may take 2 minutes, but discontinuous coverage may take 3 hours. Currently, the network has no mechanism to distinguish the reason why the UE indicates unavailability, so the network may set incorrect power saving parameters to the UE based on its understanding of the unavailability, which may vary depending on the reason. In this example, if the UE becomes unavailable for 3 minutes due to an OS upgrade and indicates that it is not available for power saving, the network may assume that the UE has become unavailable due to discontinuous coverage and set the power saving parameters to 4 hours. Therefore, the parameters given to the UE may be incorrect and may have an incorrect impact on both the UE and the network.

[0154] Furthermore, the UE is in discontinuous coverage, and if it wants to send MO data / MO signaling to the network in this situation, it needs to connect to cell T0 for uplink communication. The UE will continue searching for the network to find service and perform MO data transmission / MO signaling. However, since the UE is in discontinuous service, it will not be able to find satellite access, but the UE will continue searching for the network. This will lead to unnecessary battery consumption at the UE.

[0155] It would be desirable to solve the above problems or at least provide some alternative ways of dealing with such problems associated with discontinuous coverage.

[0156] A primary object of the embodiments herein is to provide a method for handling power saving in a UE during discontinuous coverage of a satellite access network and a satellite access network.

[0157] Another object of the embodiments herein is to send a registration request message to a network device in a satellite access network when the UE is in coverage of the satellite access network, wherein the registration request message includes an unavailable type, an unavailable parameter, and a power saving parameter.

[0158] Another object of embodiments herein is to receive a registration accept message from a network device, wherein the registration accept message includes a power saving parameter and an unavailability period duration determined by the network device based on an indication of an unavailability type and an unavailability parameter.

[0159] Another object of embodiments herein is to activate the unavailable period duration when the UE has lost coverage of the satellite access network.

[0160] Another object of embodiments herein is to determine actions for activation of the unavailability period duration to optimize power saving at the UE until coverage of the satellite access network is available.

[0161] Another object of embodiments herein is to receive optimal power saving parameters when the UE requests in a registration request message.

[0162] It is another object of embodiments herein to perform power saving based on received power saving parameters.

[0163] Embodiments disclosed herein provide a method for handling power conservation in a UE during discontinuous coverage of a satellite access network. The method includes, while the UE is in coverage of the satellite access network, sending, by the UE, a registration request message to a network device in the satellite access network. The registration request message includes an unavailability type, an unavailability parameter, and a power conservation parameter. Furthermore, the method includes, by the UE, receiving a registration accept message from the network device. The registration accept message includes at least one of a power conservation parameter and an unavailability period duration, determined by the network device based on an indication of the unavailability type and the unavailability parameter. Furthermore, the method includes, by the UE, detecting that the UE has lost coverage of the satellite access network. Furthermore, the method includes, when the UE has lost coverage of the satellite access network, activating, by the UE, an unavailability period duration. Furthermore, the method includes, by the UE, determining at least one action for activating the unavailability period duration to optimize power conservation at the UE until coverage of the satellite access network becomes available.

[0164] In an embodiment of the present disclosure, at least one action includes: configuring the UE to a 5GMM-REGISTERED.NO-CELL-AVAILABLE state.

[0165] In an embodiment of the present disclosure, the at least one action includes deactivating, by the UE, an access stratum (AS) function for new radio (NR) satellite access in a satellite access network for a duration of the unavailable period.

[0166] In an embodiment of the present disclosure, at least one action includes: determining, by the UE, a time period during which coverage of the satellite access network is available again based on the duration of the unavailable period.

[0167] In an embodiment of the present disclosure, the unavailable type indicates the cause of unavailable as discontinuous coverage due to NR satellite access discontinuous coverage. If it is set to not due to NR satellite access discontinuous coverage, the network will set appropriate power saving parameters based on its determination that the UE is not entering unavailable due to NR satellite access discontinuous coverage.

[0168] In an embodiment of the present disclosure, the unavailability parameters include the start of the unavailability period known to the UE and the duration of the unavailability period known to the UE.

[0169] In an embodiment of the present disclosure, the method includes receiving, by the UE, optimal power saving parameters when requested by the UE in a registration request message. In addition, the method includes performing, by the UE, power saving based on the received power saving parameters.

[0170] In an embodiment of the present disclosure, the optimal power saving parameter indicates at least one of a periodic registration timer, extended DRX in a CM-IDLE configuration, a MICO mode configuration, and a Next Generation Radio Access Network (NG-RAN) with extended connection time.

[0171] Embodiments disclosed herein provide a method for handling power conservation in a UE during discontinuous coverage of a satellite access network. The method includes: receiving, by a network device, a registration request message from the UE while the UE is in coverage of the satellite access network. The registration request message includes at least one of an unavailability type, an unavailability parameter, and a power conservation parameter. Furthermore, the method includes: determining, by the network device, an unavailability period duration and a power conservation parameter based on an indication of the unavailability type and the unavailability parameter, upon request by the UE. Furthermore, the method includes: sending, by the network device, a registration accept message to the UE to optimize power consumption at the UE during discontinuous coverage of the satellite access network. The registration accept message includes the unavailability period duration and the optimal power conservation parameter.

[0172] Embodiments disclosed herein provide a UE for processing power conservation in a UE during discontinuous coverage of a satellite access network. The UE includes a satellite discontinuous coverage controller coupled to a memory and a processor. The satellite discontinuous coverage controller is configured to, when the UE is in coverage of the satellite access network, send a registration request message to a network device in the satellite access network. The registration request message includes an unavailability type, an unavailability parameter, and a power conservation parameter. Furthermore, the satellite discontinuous coverage controller is configured to receive a registration accept message from the network device. The registration accept message includes the power conservation parameter and an unavailability period duration determined by the network device based on an indication of the unavailability type and the unavailability parameter. Furthermore, the satellite discontinuous coverage controller is configured to detect that the UE has lost coverage of the satellite access network. Furthermore, the satellite discontinuous coverage controller is configured to activate the unavailability period duration when the UE has lost coverage of the satellite access network. Furthermore, the satellite discontinuous coverage controller is configured to determine at least one action for the activated unavailability period duration to optimize power conservation at the UE until coverage of the satellite access network becomes available.

[0173] Embodiments disclosed herein provide a network device for processing power conservation in a UE during discontinuous coverage of a satellite access network. The network device includes a satellite discontinuous coverage controller coupled to a memory and a processor. The satellite discontinuous coverage controller is configured to receive a registration request message from the UE when the UE is in coverage of the satellite access network. The registration request message includes an unavailability type, an unavailability parameter, and a power conservation parameter. Furthermore, the satellite discontinuous coverage controller is configured to determine, upon request by the UE, an unavailability period duration and a power conservation parameter based on an indication from the unavailability type and the unavailability parameter. Furthermore, the satellite discontinuous coverage controller is configured to send a registration accept message to the UE to optimize power consumption at the UE during discontinuous coverage of the satellite access network. The registration accept message includes the unavailability period duration and the optimal power conservation parameter.

[0174] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and accompanying drawings. However, it should be understood that the following description, while indicating preferred embodiments and many of their specific details, is given by way of illustration and not limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope of the embodiments herein, and the embodiments herein include all such modifications.

[0175] Embodiments disclosed herein provide a method for handling power conservation in a UE during discontinuous coverage of a satellite access network. The method includes, while the UE is in coverage of the satellite access network, sending, by the UE, a registration request message to a network device in the satellite access network. The registration request message includes an unavailability type, an unavailability parameter, and a power conservation parameter. Furthermore, the method includes, by the UE, receiving a registration accept message from the network device. The registration accept message includes the power conservation parameter and an unavailability period duration determined by the network device based on at least one of an indication of the unavailability type and the unavailability parameter. Furthermore, the method includes, by the UE, detecting that the UE has lost coverage of the satellite access network. Furthermore, the method includes, when the UE has lost coverage of the satellite access network, activating, by the UE, the unavailability period duration. Furthermore, the method includes, by the UE, determining at least one action for activating the unavailability period duration to optimize power conservation at the UE until coverage of the satellite access network becomes available.

[0176] In an embodiment of the present disclosure, at least one action includes at least one of: configuring the UE to a 5GMM-REGISTERED.NO-CELL-AVAILABLE state; deactivating, by the UE, an access stratum (AS) function for new radio (NR) satellite access in a satellite access network for an unavailable period duration; and determining, by the UE, a time period in which coverage of the satellite access network is available again based on the unavailable period duration.

[0177] In an embodiment of the present disclosure, the unavailability type indicates the cause of unavailability as discontinuous coverage due to discontinuous coverage of NR satellite access. In an embodiment of the present disclosure, the unavailability parameters include the start of the unavailability period known to the UE and the duration of the unavailability period known to the UE.

[0178] In an embodiment of the present disclosure, the method includes: receiving, by the UE, an optimal power saving parameter when requested by the UE in a registration request message; and performing, by the UE, power saving based on the received power saving parameter. In an embodiment of the present disclosure, the optimal power saving parameter indicates at least one of a periodic registration timer, extended discontinuous reception (DRX) in a CM-IDLE configuration, a mobile initiated communications only (MICO) mode configuration, and a next generation radio access network (NG-RAN) with extended connection time.

[0179] In an embodiment of the present disclosure, a method for handling power saving in a UE during discontinuous coverage of a satellite access network includes: when the UE is in coverage of the satellite access network, receiving, by a network device, a registration request message from the UE, wherein the registration request message includes an unavailability type, an unavailability parameter, and a power saving parameter; when requested by the UE, determining, by the network device, an unavailable period duration and a power saving parameter based on an indication of the unavailability type and the unavailability parameter; and sending, by the network device, a registration accept message to the UE to optimize power consumption at the UE during the discontinuous coverage of the satellite access network, wherein the registration accept message includes the unavailable period duration and the optimal power saving parameter.

[0180] In an embodiment of the present disclosure, a UE for handling power saving in the UE during discontinuous coverage of a satellite access network comprises: a memory; a processor; and a satellite discontinuous coverage controller coupled to the memory and the processor and configured to: when the UE is in coverage of the satellite access network, send a registration request message to a network device in the satellite access network, wherein the registration request message includes an unavailability type, an unavailability parameter, and a power saving parameter; receive a registration accept message from the network device, wherein the registration accept message includes the power saving parameter and an unavailable period duration determined by the network device based on an indication of the unavailability type and the unavailability parameter; detect that the UE has lost coverage of the satellite access network; activate the unavailable period duration when the UE (100) has lost coverage of the satellite access network; and determine at least one action for the activated unavailable period duration to optimize power saving at the UE until coverage of the satellite access network is available.

[0181] In an embodiment of the present disclosure, a network device for handling power saving in a UE during discontinuous coverage of a satellite access network includes: a memory; a processor; and a satellite discontinuous coverage controller, coupled to the memory and the processor, and configured to: receive a registration request message from the UE when the UE is in coverage of the satellite access network, wherein the registration request message includes an unavailability type, an unavailability parameter, and a power saving parameter; determine an unavailability period duration and a power saving parameter based on an indication of the unavailability type and the unavailability parameter when requested by the UE; and send a registration accept message to the UE to optimize power consumption at the UE during discontinuous coverage of the satellite access network, wherein the registration accept message includes the unavailability period duration and the optimal power saving parameter.

[0182] Based on the proposed method, the UE turns off its access stratum and does not perform any search based on the unavailability period indicated by the network device to save power during discontinuous coverage. The UE explicitly indicates the unavailability type to the network device based on the indication and determination from the UE, and the UE sets the response unavailability period and power saving parameters.

[0183] Based on the proposed method, the UE indicates an unreachable period (Unavailable Duration or any other name) to the network or any network function or entity (e.g., the AMF entity / MME) in a NAS or AS signaling message (e.g., the Registration Request message). The UE may also indicate an Activity Timer or MICO Mode Indication IE / T3324 to the network or any network function or entity (e.g., the AMF entity / MME) in a NAS or AS signaling message (e.g., the Registration Request message). The message names are shown as examples only and can be any message. Optionally, the AMF entity responds to the UE with the negotiated Unreachable Period in any NAS or AS signaling message (e.g., the Registration Accept message). Optionally, the AMF entity responds to the UE with the negotiated Activity Timer value or MICO Mode Indication IE / T3324 in any NAS or AS signaling message (e.g., the Registration Accept message). The AMF entity can use this negotiated information to determine when the UE is reachable and when it is unreachable.

[0184] In an embodiment, an Unreachable Period timer is started after the Activity Timer expires. The UE and the AMF entity / MME may optionally negotiate and configure an Unreachable Period timer and an Activity Timer (T3324). The UE and the AMF entity / MME may decide to run the Activity Timer (T3324) first, and after the Activity Timer expires, the UE and the AMF entity run the Unreachable Period timer. The Activity Timer and / or the Unreachable Period timer may have any value indicated by the UE or provided by a network entity (e.g., the AMF entity). During the Activity Timer, the UE is available for paging / the network may page the UE. After the Activity Timer expires, the UE and the AMF entity start the Unreachable Period timer. During the Unreachable Period timer, the UE is considered unreachable, and the AMF entity does not page the UE and the UE will not listen for paging.

[0185] Referring now to the drawings and more particularly to Figures 1 to 10 , wherein like reference numerals indicate corresponding features consistently throughout the drawings, there is shown a preferred embodiment.

[0186] Figure 1 A block diagram of a satellite access network (1000) for satellite communications according to an embodiment of the present disclosure is shown. In an embodiment of the present disclosure, the satellite access network (1000) includes a UE (100), a satellite (200), a gateway (300), an eNB / gNB (400), and an EPC / 5GC (500). The UE (100), the satellite (200), the gateway (300), the eNB / gNB (400), and the EPC / 5GC (500) communicate with each other. Figure 1 Continuous satellite coverage is shown. In an NTN, continuous satellite coverage can be characterized by the fact that the Uu interface is available to the UE (100) 100% of the time at a given location.

[0187] Discontinuous Coverage (DC): In an NTN, discontinuous satellite coverage can be characterized by the fact that the Uu interface is available to the UE (100) less than 100% of the time at a given location due to a predictable lack of satellite coverage. Due to discontinuous coverage, the UE (100) may only have access to satellite service coverage at specific times and locations.

[0188] Satellite ephemeris information: GPS satellites transmit information about their position (current and predicted), timing, and "health" via so-called ephemeris data.

[0189] GPS receivers use this data to estimate their position relative to satellites, and thus their position on Earth. Ephemeris data can also be used to predict future satellite conditions (for a given location and time), providing a tool for planning when (or when not) to schedule GPS data collection.

[0190] Figure 2 A sequence diagram illustrating a situation in which a UE (100) and a network are out of sync, resulting in paging loss / loss of service to the UE (100) according to an embodiment of the present disclosure is shown. In step 1, the UE (100) sends a registration request including an unreachable timer and an active timer to the AMF entity (700). In step 2, the AMF entity (700) and the network data analysis function (NWDAF) entity (800) perform a reachability estimation of the UE (100). In step 3, the AMF entity (700) sends a registration acceptance including the negotiated unreachable timer and active timer. In step 4a, the UE (100) continues to listen for paging during the active timer after the MICO and ignores the unreachable timer behavior. In step 4b, priority is given to the unreachable period and the AMF entity (700) does not page the UE (100) during the active time.

[0191] In step 4c, the UE (100) may consider itself unreachable due to the unreachable timer being running and may ignore listening to paging even if the active timer is running after the MICO mode. In step 4d, the AMF entity (700) may consider the active timer of the UE (100) (with a higher priority than the unreachable timer) and may page the UE (100) during the active time (considering the UE (100) to be reachable).

[0192] In other words, the UE (100) indicates the unreachable period (unavailable duration or any name) to the network or any network function or entity (e.g., AMF entity (700)) in a NAS or AS signaling message (e.g., Registration Request message). The UE (100) may also indicate the active timer or MICO mode indication IE / T3324 to the network or any network function or entity (e.g., AMF entity (700)) in a NAS or AS signaling message (e.g., Registration Request message). The message name is shown only as an example and may be any message.

[0193] Optionally, the AMF entity (700) requests an unreachable period or reachable period estimate of the UE (100) from other network functions or entities (eg, NWDAF entity (800)).

[0194] Optionally, the AMF entity (700) replies to the UE (100) with the negotiated unreachable period in any NAS or AS signaling message (e.g., Registration Accept message). Optionally, the AMF entity (700) replies to the UE (100) with the negotiated activity timer value or MICO Mode Indication IE / T3324 in any NAS or AS signaling message (e.g., Registration Accept message). The AMF entity (700) may use the negotiated information to determine when the UE (100) is reachable and when the UE (100) is unreachable.

[0195] The UE (100) may continue to listen for paging during the active timer after the MICO and ignore the unreachable timer behavior. That is, the UE (100) may give the active timer a higher priority than the unreachable timer and consider itself reachable until the active timer is running. However, the network may consider the unreachable period of the UE (100) (higher priority than the active timer) and may consider the UE (100) unreachable if the unreachable period is running. Giving priority to the unreachable period, the network does not page the UE (100) during the active time and considers the UE (100) unreachable.

[0196] Furthermore, the UE (100) may consider itself unreachable due to the unreachable timer being running and may ignore listening for paging even if the active timer is running after the MICO mode, i.e., the UE (100) may give the unreachable timer a higher priority than the active timer and consider itself unreachable even if the active timer is running. However, the network may consider the active timer of the UE (100) (higher priority than the unreachable timer) and may consider the UE (100) reachable if the active timer is running. By giving priority to the active timer over the unreachable period, the network may page the UE (100) during the active time and consider the UE (100) reachable until the active timer is running.

[0197] In both cases (steps 4a-4d), the UE (100) may not receive a paging message or may miss a paging message from the network. The UE (100) and the network may become unsynchronized, resulting in lost paging / loss of service to the UE (100). Currently, there is no method to handle this problem, and a method needs to be defined to handle this problem.

[0198] Figure 3A sequence diagram of a UE (100) performing a cell search according to an embodiment of the present disclosure is shown. In step 1, the UE (100) is in coverage of satellite access. In step 2a, the UE (100) sends a registration request to the AMF entity (700). In step 2b, the AMF entity (700) sends a registration accept to the UE (100). In step 2c, the NG-RAN (600) performs an RRC connection release and indicates the RRC connection release to the UE (100). In step 3, cell coverage is lost due to discontinuous service at the NG-RAN (600). In step 4, the UE (100) is in discontinuous coverage. In step 5, the UE (100) has mo data to send. In step 6, the UE (100) performs a cell search but does not find a cell due to discontinuous coverage. The battery consumption of the UE increases.

[0199] In other words, the UE is in the coverage of satellite access. The UE (100) and the AMF entity (700) (or any network function or entity) may negotiate or determine the PSM / MICO mode parameters and the activity timer value. The UE (100) enters the PSM / MICO mode and when the activity timer / T3324 expires, the UE (100) stops listening for paging.

[0200] Optionally, when the unreachable period timer (or any timer name used to track unreachable or unavailable periods) has started and there is no service due to loss of NTN cell coverage, the UE (100) enters discontinuous service (unreachable period). In addition, the UE (100) may determine that coverage has been lost. That is, because of the discontinuous coverage, the UE (100) optionally enters any of the NO SERVICE (NO-CELL-AVAILABLE) state or the 5G MM sublayer state or the EMM sublayer state, optionally by deactivating the access stratum, due to at least one of broadcast information from a RAN node (such as a gNodeB or eNodeB) or from a 5GC (500) or from an application server or any other mechanism.

[0201] Furthermore, the UE (100) remains in discontinuous coverage for the determined discontinuous coverage period and waits for the UE (100) to return to coverage. Now, if the UE (100) has mo data / mo signaling to send to the network, the UE (100) needs to connect to the cell for uplink communication. The UE (100) keeps searching the network to find service and perform mo data transmission / mo signaling. However, since the UE (100) is in discontinuous service, the UE (100) does not find satellite access and keeps searching the network. This will result in unnecessary battery consumption at the UE (100). Currently, there is no method to handle this situation and a method needs to be defined.

[0202] Figure 4 A sequence diagram illustrating a UE (100) and an AMF entity (700) for handling power saving in the UE (100) during discontinuous coverage of a satellite access network (1000) according to an embodiment of the present disclosure. In step 1, the UE (100) sends a Registration Request including an Unreachable Timer and an Activity Timer to the AMF entity (700). In step 2, the AMF entity (700) sends a Registration Accept including the negotiated Unreachable Timer and Activity Timer.

[0203] In other words, the UE (100) indicates the unreachable period (unavailable duration or any name) to the network or any network function or entity (e.g., AMF entity (700) / MME) in a NAS or AS signaling message (e.g., Registration Request message). The UE (100) may also indicate the active timer or MICO mode indication IE / T3324 to the network or any network function or entity (e.g., AMF entity (700)) in a NAS or AS signaling message (e.g., Registration Request message). The message name is shown only as an example and may be any message.

[0204] Optionally, the AMF entity (700) or any network entity replies to the UE (100) with the negotiated unreachable period in any NAS or AS signaling message (e.g., Registration Accept message). Optionally, the AMF entity (700) or any network entity replies to the UE (100) with the negotiated activity timer value or MICO mode indication IE / T3324 in any NAS or AS signaling message (e.g., Registration Accept message). The AMF entity (700) or any network entity may use the negotiated information to determine when the UE (100) is reachable and when the UE (100) is unreachable.

[0205] The UE (100) and / or network entity (e.g. AMF entity (700)) may perform any of the following procedures in any order or combination:

[0206] In an embodiment of the present disclosure, the unreachable period timer is started after the activity timer expires.

[0207] The UE (100) and the AMF entity (700) / MME may optionally negotiate and configure an unreachable period timer and an activity timer (T3324).

[0208] The UE (100) and the AMF entity (700) / MME may decide to run the activity timer (T3324) first, and after the activity timer expires, the UE (100) and the AMF entity (700) run the unreachable period timer. The activity timer and / or the unreachable timer may have any value among the values ​​indicated by the UE (100) or the values ​​provided by the network entity (e.g., the AMF entity (700)). Thus, during the activity timer, the UE (100) may be available for paging / the network may page the UE (100), and after the activity timer expires or after the activity timer stops, the UE (100) and the AMF entity (700) start the unreachable period timer.

[0209] During the unreachable period timer, the UE (100) is considered unreachable and the AMF entity (700) does not page the UE (100) and the UE (100) does not listen to paging.

[0210] In an embodiment of the present disclosure, the UE (100) and the AMF entity (700) may start both the unreachable period timer and the activity timer simultaneously or concurrently, but the UE (100) is considered reachable until the activity timer runs, i.e., until the activity timer expires or stops.

[0211] The activity timer and / or the unreachable timer may have any value among the values ​​indicated by the UE (100) or the values ​​provided by the network entity (e.g. AMF entity (700) / MME). Thus, during the activity timer, after the activity timer expires or after the activity timer stops and the UE (100) is available for paging / the network may page the UE (100), the UE (100) is considered unreachable and the network (e.g. AMF entity (700)) will not page the UE (100) and the UE (100) will not listen for paging.

[0212] When the activity timer expires, the UE (100) becomes unavailable or unreachable for the remainder of the unreachable period timer. If the activity timer value is higher than the unreachable period timer, the device remains reachable for the entire duration and the network may page the UE (100) for the duration that the activity timer is running.

[0213] In addition, the UE (100) listens for paging messages while the activity timer is running. The AMF entity (700) can page the UE (100) until the activity timer expires.

[0214] In an embodiment of the present disclosure, the UE (100) and the AMF entity (700) may negotiate in any NAS or AS message or any signalling message or any configuration / pre-configuration message / file / SIM file or flag as to which timer to run first and which timer to run later or which timer to ignore or which timer to give priority or what the value of the timer to run in any of the AS or NAS signalling messages should be.

[0215] In an embodiment of the present disclosure, the UE (100) / AMF entity (700) ignores (or does not indicate) the activity timer or MICO mode indication IE / T3324 (during the registration procedure or any signaling procedure) and only considers the unreachable period timer (or unreachable duration or any name) (i.e., the unreachable period timer is given priority).

[0216] For example, if the UE (100) optionally determines both the MICO mode and the unreachable period timer, the UE (100) supports the unreachable period or may / needs to indicate the unreachable period to the network entity (e.g., AMF entity (700) / MME), the UE (100) does not indicate the active timer during the AS / NAS signaling message exchange (e.g., registration request message), i.e., if the UE (100) includes the unreachable period (e.g., unavailable duration, etc.) in the NAS or AS message, the UE (100) does not include the MICO mode indication IE / T3324 / eDRX parameter (cycle) or any other power saving parameter.

[0217] If the UE (100) (optionally) indicates one or both of the unreachable period timer and the MICO mode indication (optionally including T3324), the network entity (e.g., the AMF entity (700) / MME) may consider only the unreachable period timer and may ignore the active timer when determining whether the UE (100) is reachable, and may provide the UE (100) with an indication that only the unreachable period timer is considered and the active timer is ignored by including only the unreachable period timer through any AS / NAS signaling message exchange (e.g., in a registration accept message). That is, at any point based on a determination that the UE (100) is about to enter discontinuous coverage, the AMF entity (700) may indicate the unreachable period to the UE (100).

[0218] In an embodiment of the present disclosure, the UE (100) / AMF entity (700) ignores (or does not indicate) the Unreachable Period Timer (or Unreachable Duration or whatever it is called) (during the registration procedure or any signaling procedure) and only considers the Active Timer or MICO Mode Indication IE / T3324. (i.e., the Active Timer is given priority).

[0219] For example, if the UE (100) determines both the MICO mode and the unreachable period timer, the UE (100) may indicate the MICO mode indication (optionally including T3324) / or any other power saving parameters to the network entity (e.g., AMF entity (700) / MME), and then the UE (100) does not indicate the unreachable period (unavailable duration) to the network during the AS / NAS signaling message exchange (e.g., registration request message). That is, if the UE (100) includes the MICO mode indication IE / T3324 / power saving parameters, the UE (100) does not include the unreachable period (unavailable duration).

[0220] If the UE (100) (optionally) indicates one or both of the unreachable period timer and the MICO mode indication (optionally including T3324), the network entity (e.g., the AMF entity (700) / MME) may consider only the MICO mode indication IE / T3324 when determining whether the UE (100) is reachable and may ignore the unreachable period (unavailable duration), and may provide the UE (100) with an indication of considering only the MICO mode indication IE / T3324 and ignoring the unreachable period (unavailable duration) by including only the MICO mode indication IE / T3324 through any AS / NAS signaling message exchange (e.g., in a Registration Accept message). The message name is shown only as an example and may be any message.

[0221] In an embodiment of the present disclosure, the UE (100) may indicate the priority of the timers between the active timer and the unreachable timer (e.g., which one needs to be run (or considered) or run first, and which one needs to be ignored or run later) during an AS / NAS signaling message exchange (e.g., a Registration Request message). The network entity (e.g., the AMF entity (700) or the MME) may consider and take this into account to decide which one to apply. In an embodiment of the present disclosure, the network entity (e.g., the AMF entity (700) or the MME) may ignore the priority of the timer indicated by the UE (100) and may apply / run / consider any timer value based on network decision or implementation. When the network entity (e.g., the AMF entity (700)) decides which timer to run first and which timer to ignore / run later, the network entity (AMF entity (700)) may indicate the timer to the UE (100) through any AS / NAS signaling message exchange (e.g., a Registration Accept message).

[0222] In an embodiment of the present disclosure, a network entity (e.g., an AMF entity (700) or an MME) may indicate a priority of timers between an active timer and an unreachable timer (e.g., which one will need to run or run first, and which one needs to be ignored or run later) during an AS / NAS signaling message exchange (e.g., a registration accept message). The UE (100) may consider and take into account to decide which one to apply. In an embodiment of the present disclosure, the UE (100) may ignore the priority of the timer indicated by the network entity (AMF entity (700) or an MME) and may apply / run / consider any timer value based on the UE (100) decision or implementation. When the UE (100) decides which timer to run first and which timer to ignore / run later, the UE (100) may indicate the timer to the network entity (AMF entity (700)) through any AS / NAS signaling message exchange. The network entity (AMF entity (700)) may accept or reject the UE's decision and may force the UE (100) to run the timer that the network entity wants to prioritize.

[0223] In the embodiments of the present disclosure, the discussed solutions are also applicable to other timer / power saving parameters, such as eDRX, periodic TAU timer, etc.

[0224] The method proposed in the embodiment is shown using MICO mode and / or activity timer as an example. The proposed method is applicable to any power saving mode (PSM) of any RAT. The proposed method is applicable to any power saving mechanism / timer / parameter, but is not limited to or restricted to only these, as shown below:

[0225] 1. Active time / MICO mode with active time,

[0226] 2. Extended connection time / MICO mode with extended connection time,

[0227] 3. Periodic TAU timer / periodic update timer,

[0228] 4. Periodic registration timer / periodic registration update timer,

[0229] 5. eDRX parameters (such as cycle length), and

[0230] 6. Duration of unavailable period: unreachable period or unreachable / unavailable information.

[0231] Basically all the above parameters / timers / information are used by the UE (100) and the network to save power. Therefore, in this embodiment, these parameters are collectively referred to as power saving parameters.

[0232] In an embodiment of the present disclosure, a UE (100) may indicate that the UE (100) is requesting power saving parameters due to the UE (100) entering discontinuous coverage. The UE (100) may determine that the UE (100) is entering discontinuous coverage by any of the following: by entering a no service or NO CELL AVAILABLE state or one of the 5GMM sublayer states or one of the EMM sublayer states, or by deactivating the access stratum or deactivating the access stratum for the duration of the discontinuous coverage. For example, the UE (100) may also include an indication in a registration request message / TAU message or any AS or NAS signaling message (the indication may be a new information element or some existing information element in a NAS or AS message) along with an activity timer value / PSM timer value requested by the UE (100) or an eDRX value or PTAU value requested by the UE (100).

[0233] When the UE (100) knows that PSM or no service or deactivation of the access stratum is due to discontinuous coverage, then the UE (100) may enter sleep mode regardless of PSM / MICO / eDRX. The UE (100) may remain out of service, for example, by deactivating the access stratum for the duration of the discontinuous coverage.

[0234] Optionally, the UE (100) may indicate that the UE (100) is requesting power saving parameters due to discontinuous coverage by including an unreachable period (or unavailable period duration or any name) (also referred to as a timer / parameter in an embodiment, or the UE (100) may be a new dedicated indication indicating power saving parameter request due to discontinuous coverage or not due to discontinuous coverage).

[0235] In an embodiment of the present disclosure, when the UE (100) indicates an unavailable period duration to the AMF entity (700) / network or the UE (100) indicates a leave coverage indication to the AMF entity (700) / network, the UE (100) enters an out-of-service or deactivated (i.e., deactivated) access stratum.

[0236] In an embodiment of the present disclosure, since the UE (100) is entering discontinuous coverage, the AMF entity (700) may also include an indication of the value provided to the UE (100) when sending the activity timer, PSM timer or eDRX value or periodic timer value.

[0237] If the AMF entity (700) determines that the UE (100) has requested power saving parameters and the UE (100) is entering discontinuous coverage (the AMF entity (700) may determine this based on an indication from the UE (100) or any other method as discussed in the embodiments), the AMF entity (700) sets the power saving parameters / timers based on the requested values ​​from the UE (100), for example, if the AMF entity (700) is not aware of the discontinuous coverage information of the UE (100), for example, when the AMF entity (700) is not aware of the NG-RAN satellite access deployment, the AMF entity (700) cannot calculate the discontinuous coverage time / period of the UE (100), the request is triggered by satellite access. If the AMF entity (700) is aware of the UE (100) entering discontinuous coverage time / period / duration, the AMF may set the power saving parameters / timers based on its knowledge after considering the parameters requested by the UE (100), the UE trajectory, the UE (100) mobility, or by ignoring the parameters requested by the UE (100).

[0238] If the AMF entity (700) determines that the UE (100) does not request the power saving parameter due to entering discontinuous coverage, the AMF entity (700) may indicate the corresponding power saving parameter to the UE (100) / NG-RAN (600) based on the AMF entity (700) determining whether the UE (100) enters discontinuous coverage.

[0239] Figure 5 A sequence diagram illustrating a UE (100) determining that an unreachable period acceptance timer is running according to an embodiment of the present disclosure.

[0240] In step 1, the UE (100) is in coverage of satellite access. In step 2a, the UE (100) sends a registration request to the AMF entity (700). In step 2b, the AMF entity (700) sends a registration acceptance including an unreachable period acceptance timer and an unreachable period wait timer to the UE (100). In step 2c, the NG-RAN (600) performs an RRC connection release during the unreachable period wait timer and indicates the RRC connection release to the UE (100). In step 3, cell coverage is lost due to discontinuous service at the NG-RAN (600). In step 4, the UE (100) is in discontinuous coverage. In step 5, the UE (100) has mo data to send. In step 6, the UE (100) determines that the "unreachable period acceptance timer" is running, so that the UE (100) does not perform a cell search.

[0241] In other words, the UE (100) is in coverage of satellite access. The UE (100) and the AMF entity (700) (or any network function or entity) may negotiate or determine PSM / MICO mode parameters and activity timer / or MICO mode indication IE / T3324 value or any power saving parameters (e.g., unavailable information / period duration).

[0242] The AMF entity (700) provides a timer (e.g., unreachable period accept timer, or the timer may be named anything) in any AS or NAS signaling message (e.g., registration accept message) or when releasing an RRC connection or in a part of any AS / NAS message. The UE (100) starts the timer when the UE (100) enters discontinuous coverage, or when the UE (100) receives a NAS / AS message from the network including the timer, or based on some indication from the network to start the timer. The timer may be a single value (or any value) of duration or time period in seconds or a tuple of a start time and an end time indicating when the timer value starts and ends. The end time may be an explicit value or may be determined by the start time and the duration in seconds. The UE (100) avoids performing / does not perform the PLMN search / scan / selection procedure or the cell search / scan / selection / reselection procedure while the timer is running (i.e., the UE (100) considers this as a discontinuous coverage period), for example, by entering an out of service state or by deactivating the access stratum. When the timer or duration expires or stops, the UE (100) starts to perform the PLMN / cell search / selection / reselection process again. In an embodiment of the present disclosure, when the timer or duration expires or stops or due to any indication from an upper layer (e.g., turning off and on, etc.) / network / UE (100), the UE (100) starts to perform the PLMN / cell search / selection / reselection process again.

[0243] In an embodiment of the present disclosure, a network entity / network function (e.g., an AMF entity (700)) may provide a timer value (e.g., an unreachable period wait timer or any other name) after which the UE (100) enters discontinuous coverage with the aforementioned timer value (e.g., an unreachable period accept timer or an unreachable period accept timer may be any name). The UE (100) knows when the UE (100) applies power saving or until when the UE (100) must send / receive data. In other words, the UE (100) knows when the discontinuous coverage starts by taking this into account. The UE (100) uses power saving while initiating the NAS procedure, with sufficient time to complete the NAS procedure before the unreachable period starts.

[0244] The network device notes that it only pages the UE (100) if there is sufficient time to complete the NAS procedure before entering discontinuous coverage (optionally also taking into account the amount of data to be processed and the time it may take). In addition, the UE (100) enters PSM / MICO mode and upon expiration of the activity timer / T3324, the UE (100) stops listening for paging.

[0245] In an embodiment of the present disclosure, the UE (100) enters discontinuous service (unreachable period), optionally when the unreachable period timer (or any timer name for tracking unreachable or unavailable period) has started, due to NTN cell coverage loss and the UE (100) has no service. In an embodiment of the present disclosure, due to discontinuous coverage, optionally due to at least one of broadcast information from a RAN node (such as a gNodeB or eNodeB), or receiving a signaling message from a 5GC (500) or from an application server or any other mechanism, the UE (100) can determine that coverage has been lost, i.e., the UE (100) optionally enters any of the NO SERVICE (NO-CELL-AVAILABLE) state or the 5GMM sublayer state or the EMM sublayer state by deactivating the access stratum.

[0246] Furthermore, the UE (100) remains in discontinuous coverage for the determined discontinuous coverage period and waits for the UE (100) to return to coverage.

[0247] Now, if the UE (100) has mo data / mo signaling to send to the network device (900), the UE (100) needs to connect to a cell for uplink communication.

[0248] Furthermore, the UE (100) determines that an "unreachable period acceptance timer" or an unavailable period duration acceptance timer (or any name) is running, so that the UE (100) does not perform a PLMN / cell scan / search / selection / reselection procedure.

[0249] If the UE (100) determines that the "unreachable period acceptance timer" is not running, the UE (100) may perform a PLMN / cell scan / search / selection / reselection procedure.

[0250] In an embodiment of the present disclosure, if the UE (100) changes its mobility mode / trajectory, such as stationary to non-stationary or non-stationary to stationary, based on the GPS location and NTN cell ephemeris or based on a change in the direction in which the UE (100) is moving, or the UE (100) determines based on an implementation that the UE (100) can obtain service, the UE (100) stops the unreachable period acceptance timer / duration and begins a PLMN search / scan / selection process or a cell search / scan / selection / reselection process. Since the direction / location of the UE (100) has changed, the discontinuous service information is no longer applicable, and the UE (100) can find cell coverage when performing a cell search.

[0251] Figure 6 A block diagram of a satellite access network (1000) for processing power saving in a UE (100) during discontinuous coverage of the satellite access network (1000) according to an embodiment of the present disclosure is shown. In the embodiments of the present disclosure, the satellite access network (1000) may be, for example, but not limited to, a fourth generation (4G) network, a fifth generation (5G) network, an open radio access network (ORAN), etc.

[0252] A satellite access network (1000) includes a UE (100) and a network device (900). The UE (100) may be, for example, but not limited to, a laptop, a smartphone, 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, an immersive device, and an Internet of Things (IoT) device. The network device (900) may be, for example, but not limited to, an AMF device, a MME, etc.

[0253] When the UE (100) is in coverage of the satellite access network (1000), the UE (100) sends a registration request message to the network device (900) in the satellite access network (1000). The registration request message includes at least one of an unavailable type, an unavailable parameter, and a power saving parameter. In an embodiment of the present disclosure, the unavailable type indicates the cause of unavailability as discontinuous coverage due to NR satellite access discontinuous coverage. If it is set to not due to NR satellite access discontinuous coverage, the network will set appropriate power saving parameters based on its determination that the UE (100) is not in unavailable due to NR satellite access discontinuous coverage. In an embodiment of the present disclosure, the unavailable parameter includes the start of the unavailable period known to the UE (100) and the duration of the unavailable period known to the UE (100). In addition, the network device (900) determines the unavailable period duration and the power saving parameter based on at least one of the indication of the unavailable type and the unavailable parameter when requested by the UE (100). Furthermore, the network device (900) sends a registration accept message to the UE (100) to optimize power consumption at the UE (100) during discontinuous coverage of the satellite access network (1000). The registration accept message includes the unavailable period duration and the optimal power saving parameter.

[0254] Furthermore, the UE (100) receives a registration accept message from the network device (900). The registration accept message includes a power saving parameter and an unavailable period duration determined by the network device (900) based on an indication of an unavailable type and an unavailable parameter. Furthermore, the UE (100) detects that the UE (100) has lost coverage of the satellite access network (1000). Furthermore, when the UE (100) has lost coverage of the satellite access network (1000), the UE (100) activates the unavailable period duration. Furthermore, the UE (100) determines an action for the activated unavailable period duration to optimize power saving at the UE (100) until coverage of the satellite access network (1000) is available.

[0255] In an embodiment of the present disclosure, the action comprises configuring the UE (100) to a 5GMM-REGISTERED.NO-CELL-AVAILABLE state. In an embodiment of the present disclosure, the action comprises deactivating an AS function for NR satellite access in the satellite access network (1000) for a duration of the unavailable period. In an embodiment of the present disclosure, the action comprises determining a time period during which coverage of the satellite access network (1000) becomes available again based on the duration of the unavailable period.

[0256] In an embodiment of the present disclosure, when the UE (100) requests in a registration request message, the UE (100) receives an optimal power saving parameter. In an embodiment of the present disclosure, the optimal power saving parameter indicates at least one of a periodic registration timer, extended DRX in a CM-IDLE configuration, a MICO mode configuration and an NG-RAN (600) with an extended connection time, an unavailable period parameter (such as an unavailable period, etc.). Based on the received power saving parameter, the UE (100) performs power saving.

[0257] The UE (100) shuts down its access layer and does not perform any search based on the unavailable period indicated by the network device (900) to save power during the discontinuous coverage period. The UE (100) explicitly indicates the unavailable type to the network device (900) based on the indication and determination from the UE (100), and the UE (100) sets the response unavailable period and power saving parameters.

[0258] In an embodiment of the present disclosure, a UE (100) indicates an unavailable type to a network to indicate a reason why the UE (100) is entering unavailable, based on which the network determines power saving parameters (e.g., periodic registration timer value, eDRX, MICO, unavailable period duration) and unavailable parameters (e.g., unavailable duration). The unavailable type value may be that the UE is entering unavailable due to NR satellite access discontinuous coverage, or it may be set to not due to NR satellite access discontinuous coverage.

[0259] Figure 7 Various hardware components of a UE (100) according to an embodiment of the present disclosure are shown. In an embodiment of the present disclosure, the UE (100) includes a processor (110), a communicator (120), a memory (130), and a satellite discontinuous coverage controller (140). The processor (110) is coupled to the communicator (120), the memory (130), and the satellite discontinuous coverage controller (140).

[0260] When the UE (100) is in coverage of the satellite access network (1000), the satellite discontinuous coverage controller (140) sends a registration request message to the network device (900) in the satellite access network (1000). The registration request message includes an unavailable type, an unavailable parameter, and a power saving parameter. In addition, the satellite discontinuous coverage controller (140) receives a registration accept message from the network device (900). The registration accept message includes the power saving parameter and the unavailable period duration determined by the network device (900) based on an indication of the unavailable type and the unavailable parameter. In addition, the satellite discontinuous coverage controller (140) detects that the UE (100) has lost coverage of the satellite access network (1000). In addition, when the UE (100) has lost coverage of the satellite access network (1000), the satellite discontinuous coverage controller (140) activates the unavailable period duration. Furthermore, the satellite discontinuous coverage controller (140) determines actions for the duration of the unavailable period for activation to optimize power saving at the UE (100) until coverage of the satellite access network (1000) is available.

[0261] In an embodiment of the present disclosure, when a UE (100) requests in a registration request message, a satellite discontinuous coverage controller (140) receives optimal power saving parameters. Based on the received power saving parameters, the satellite discontinuous coverage controller (140) performs power saving.

[0262] The AMF entity (700) provides the UE (100) with an unavailability duration. Based on the unavailability duration received from the AMF entity (700), the UE (100) deactivates the access stratum, enters the NO CELL AVAILABLE state, and determines when coverage returns. The UE (100) explicitly indicates the type of unavailability to the network device (900). Based on the unavailability type and the duration of the unavailability period, the UE (100) sets power saving parameters.

[0263] The satellite discontinuous coverage controller (140) is 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, hard-wired circuits, etc., and may optionally be driven by firmware.

[0264] The processor (110) may include one or more processors. The one or more processors may be general-purpose processors (such as a central processing unit (CPU), an application processor (AP), etc.), graphics processing units (such as a graphics processing unit (GPU), a visual processing unit (VPU)), and / or AI-specific processors (such as a neural processing unit (NPU)). The processor (110) may include multiple cores and be configured to execute instructions stored in the memory (130). The processor (110) controls the satellite discontinuous coverage controller (140) to perform various operations.

[0265] The processor (110) indicates a registration request message including an unavailability type to an access and mobility management function (AMF), receives a registration accept message including an unavailability period duration from the AMF, wherein the unavailability period duration is determined by the AMF based on the unavailability type, and performs at least one action during the unavailability period duration.

[0266] The processor (110) enters 5GMM-REGISTERED.NO-CELL-AVAILABLE, deactivates the access layer, and determines when to return to coverage.

[0267] The processor (110) requests a power saving parameter from the AMF, wherein the power saving parameter is determined by the AMF based on the unavailable period duration.

[0268] Furthermore, the processor (110) is configured to execute instructions stored in the memory (130) and perform various processes. The communicator (120) is configured to communicate internally between internal hardware components and to communicate with external devices via one or more networks. The memory (130) also stores instructions to be executed by the processor (110). The memory (130) may include a non-volatile storage element. Examples of such non-volatile storage elements may include a magnetic hard disk, an optical disk, a floppy disk, a flash memory, or a form of electrically programmable memory (EPROM) or electrically erasable and programmable memory (EEPROM). Additionally, in some examples, the memory (130) may 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 propagating signal. However, the term "non-transitory" should not be interpreted as meaning that the memory (130) is non-removable. In some examples, a non-transitory storage medium may store data that may change over time (e.g., in random access memory (RAM) or cache memory).

[0269] In an embodiment of the present disclosure, the communicator (120) includes electronic circuitry specific to a standard for implementing wired or wireless communications. The communicator (120) is configured to communicate internally between internal hardware components of the UE (100) and to communicate with external devices via one or more networks.

[0270] although Figure 7 Various hardware components of the UE (100) are shown, but it should be understood that other embodiments are not limited thereto. In the embodiments of the present disclosure, the UE (100) may include fewer or greater numbers of components. In addition, the labels or names of the components are for illustrative purposes only and do not limit the scope of the present invention. One or more components may be combined to perform the same or substantially similar functions in the UE (100).

[0271] Figure 8 Various hardware components of a network device (900) according to an embodiment of the present disclosure are shown. In an embodiment of the present disclosure, the network device (900) includes a processor (910), a communicator (920), a memory (930), and a satellite discontinuous coverage controller (940). The processor (910) is coupled to the communicator (920), the memory (930), and the satellite discontinuous coverage controller (940).

[0272] When a UE (100) is in coverage of a satellite access network (1000), a satellite discontinuous coverage controller (940) receives a registration request message from the UE (100). The registration request message includes an unavailability type, an unavailability parameter, and a power saving parameter. Furthermore, the satellite discontinuous coverage controller (940) determines an unavailability period duration and a power saving parameter based on an indication of the unavailability type and the unavailability parameter when requested by the UE (100). Furthermore, the satellite discontinuous coverage controller (940) sends a registration accept message to the UE (100) to optimize power consumption at the UE (100) during discontinuous coverage of the satellite access network (1000). The registration accept message includes the unavailability period duration and the optimal power saving parameter.

[0273] The satellite discontinuous coverage controller (940) is 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, hard-wired circuits, etc., and may optionally be driven by firmware.

[0274] The processor (910) may include one or more processors. The one or more processors may be general-purpose processors (such as a central processing unit (CPU), an application processor (AP), etc.), graphics processing units (such as a graphics processing unit (GPU), a visual processing unit (VPU)), and / or AI-specific processors (such as a neural processing unit (NPU)). The processor (910) may include multiple cores and be configured to execute instructions stored in the memory (930). The processor (910) controls the satellite discontinuous coverage controller (940) to perform various operations.

[0275] The processor (910) obtains a registration request message including an unavailability type, determines an unavailability period duration based on the unavailability type, and sends a registration accept message including the unavailability period duration to a user equipment (UE).

[0276] When requesting the power saving parameter from the UE, the processor (910) determines the power saving parameter based on the unavailable period duration.

[0277] Furthermore, the processor (910) is configured to execute instructions stored in the memory (930) and perform various processes. The communicator (920) is configured to communicate internally between internal hardware components and to communicate with external devices via one or more networks. The memory (930) also stores instructions to be executed by the processor (910). The memory (930) may include a non-volatile storage element. Examples of such non-volatile storage elements may include a magnetic hard disk, an optical disk, a floppy disk, a flash memory, or a form of electrically programmable memory (EPROM) or electrically erasable and programmable memory (EEPROM). Additionally, in some examples, the memory (930) may 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 propagating signal. However, the term "non-transitory" should not be interpreted as meaning that the memory (930) is non-removable. In some examples, a non-transitory storage medium may store data that may change over time (e.g., in random access memory (RAM) or cache memory).

[0278] In an embodiment of the present disclosure, the communicator (920) includes electronic circuitry specific to a standard for implementing wired or wireless communications. The communicator (920) is configured to communicate internally between internal hardware components of the UE (100) and to communicate with external devices via one or more networks.

[0279] although Figure 8Various hardware components of the network device (900) are shown, but it should be understood that other embodiments are not limited thereto. In embodiments of the present disclosure, the network device (900) may include fewer or greater numbers of components. Furthermore, the labels or names of the components are for illustrative purposes only and do not limit the scope of the present invention. One or more components may be combined to perform the same or substantially similar functions in the network device (900).

[0280] Figure 9 The present invention is a flowchart (S900) illustrating a method implemented by a UE (100) for handling power saving in a UE (100) during discontinuous coverage of a satellite access network (1000) according to an embodiment of the present disclosure. Operations (S902-S910) are handled by a satellite discontinuous coverage controller (140).

[0281] At S902, the method includes sending a registration request message to a network device (900) when the UE (100) is in coverage of the satellite access network (1000). The registration request message includes at least one of an unavailability type, an unavailability parameter, and a power saving parameter. At S904, the method includes receiving a registration accept message from the network device (900). The registration accept message includes at least one of a power saving parameter and an unavailable period duration determined by the network device (900) based on an indication of the unavailability type and the unavailability parameter. At S906, the method includes detecting that the UE (100) has lost coverage of the satellite access network (1000). At S908, the method includes activating the unavailable period duration when the UE (100) has lost coverage of the satellite access network (1000). At S910, the method includes an action of determining the unavailable period duration for activation to optimize power saving at the UE (100) until coverage of the satellite access network (1000) is available.

[0282] In an embodiment of the present disclosure, the action comprises configuring the UE (100) to a 5GMM-REGISTERED.NO-CELL-AVAILABLE state. In an embodiment of the present disclosure, the action comprises deactivating an AS function for NR satellite access in the satellite access network (1000) for a duration of the unavailable period. In an embodiment of the present disclosure, the action comprises determining a time period during which coverage of the satellite access network (1000) becomes available again based on the duration of the unavailable period.

[0283] Figure 10The present invention is a flowchart (S1000) illustrating a method implemented by a network device (900) for handling power saving in a UE (100) during discontinuous coverage of a satellite access network (1000) according to an embodiment of the present disclosure. Operations (S1002-S1006) are handled by a satellite discontinuous coverage controller (940).

[0284] At S1002, the method includes receiving a registration request message from a UE (100) when the UE (100) is in coverage of a satellite access network (1000). The registration request message includes at least one of an unavailability type, an unavailability parameter, and a power saving parameter. At S1004, the method includes determining at least one of an unavailability period duration and a power saving parameter based on an indication of the unavailability type and an indication of the unavailability parameter when requested by the UE (100). At S1006, the method includes sending a registration accept message to the UE (100) to optimize power consumption at the UE (100) during discontinuous coverage of the satellite access network (1000). The registration accept message includes at least one of an unavailability period duration and an optimal power saving parameter.

[0285] In an embodiment of the present disclosure, a method performed by a user equipment (UE) includes: entering 5G MM-REGISTERED.NO-CELL-AVAILABLE; deactivating the access stratum; and determining when to return to coverage.

[0286] In an embodiment of the present disclosure, the unavailability type indicates a reason for unavailability due to discontinuous coverage. In an embodiment of the present disclosure, a method performed by a user equipment (UE) includes requesting a power saving parameter, wherein the power saving parameter is determined by an AMF based on an unavailable period duration.

[0287] In an embodiment of the present disclosure, the power saving parameter includes at least one of a periodic registration update timer, extended discontinuous reception (DRX) in a CM-IDLE configuration, a mobile initiated communications only (MICO) mode configuration, and a next generation radio access network (NG-RAN) with extended connection time. In an embodiment of the present disclosure, the registration request message includes at least one of a MICO indication, a requested active time, and a requested DRX parameter.

[0288] In an embodiment of the present disclosure, at least one processor is configured to: enter 5GMM-REGISTERED.NO-CELL-AVAILABLE, deactivate the access stratum, and determine when to return to coverage. In an embodiment of the present disclosure, at least one processor is configured to: request a power saving parameter from the AMF, wherein the power saving parameter is determined by the AMF based on the duration of the unavailable period.

[0289] In an embodiment of the present disclosure, at least one processor is configured to determine the power saving parameter based on the unavailable period duration when the power saving parameter is requested from the UE.

[0290] The various actions, behaviors, blocks, steps, etc. in the flowcharts (S900 and S1000) can be performed in the order presented, in a different order, or simultaneously. In addition, in some embodiments, some of the actions, behaviors, blocks, steps, etc. can be omitted, added, modified, skipped, etc. without departing from the scope of the present invention.

[0291] The foregoing description of the specific embodiments will fully reveal the general nature of the embodiments herein so that others can easily modify or adapt such specific embodiments for various applications by applying current knowledge without departing from the general concepts, and therefore, such adjustments and modifications should and are intended to be understood as being within the meaning and range of equivalents of the disclosed embodiments. It should be understood that the wording or terminology employed herein is for purposes of description and not limitation. Therefore, although the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein may be practiced by modification within the scope of the embodiments as described herein.

Claims

1. A method performed by a user equipment (UE), the method comprising: Indicate to the Access and Mobility Management Function (AMF) that the Registration Request message includes the unavailable type; 1. receiving a Registration Accept message from the AMF including an Unavailability Period duration, wherein the Unavailability Period duration is determined by the AMF based on the Unavailability Type; and At least one action is performed during the duration of the unavailable period.

2. The method according to claim 1, wherein Performing at least one action during the duration of the unavailable period includes: Enter 5GMM-REGISTERED.NO-CELL-AVAILABLE; Deactivating the access stratum; and Determines when to return to coverage.

3. The method according to claim 1, wherein The unavailability type indicates the reason for the unavailability due to discontinuous coverage.

4. The method according to claim 1, further comprising: Request power saving parameters from the AMF, where the power saving parameters are determined by the AMF based on the duration of the unavailable period.

5. The method according to claim 4, wherein The power saving parameter includes at least one of a periodic registration update timer, extended discontinuous reception (DRX) in a CM-IDLE configuration, a mobile originated communications only (MICO) mode configuration, and a next generation radio access network (NG-RAN) with extended connection time.

6. The method according to claim 1, wherein The registration request message includes at least one of a MICO indication, a requested active time, and a requested DRX parameter.

7. A user equipment (UE), comprising: transceiver; and at least one processor coupled to the transceiver, configured to: Indicates to the Access and Mobility Management Function (AMF) that the Registration Request message includes the unavailable type, receiving a Registration Accept message from the AMF including the duration of the Unavailability Period, wherein the duration of the Unavailability Period is determined by the AMF based on the Unavailability Type, and At least one action is performed during the duration of the unavailable period.

8. The UE according to claim 7, wherein: The at least one processor is configured to: Enter 5GMM-REGISTERED.NO-CELL-AVAILABLE, Deactivate the access layer, and Determines when to return to coverage.

9. The UE according to claim 7, wherein: The unavailability type indicates the reason for unavailability due to discontinuous coverage.

10. The UE according to claim 7, wherein: The at least one processor is further configured to: Request power saving parameters from the AMF, where the power saving parameters are determined by the AMF based on the duration of the unavailable period.

11. The UE according to claim 7, wherein: The power saving parameter includes at least one of a periodic registration update timer, extended discontinuous reception (DRX) in a CM-IDLE configuration, a mobile originated communications only (MICO) mode configuration, and a next generation radio access network (NG-RAN) with extended connection time.

12. The UE according to claim 7, wherein: The registration request message includes at least one of a MICO indication, a requested active time, and a requested DRX parameter.

13. An access and mobility management function (AMF), comprising: transceiver; and at least one processor coupled to the transceiver, configured to: Get a registration request message including an unavailable type, determining the duration of the unavailability period based on the type of unavailability, and A registration accept message including the duration of the unavailable period is sent to a user equipment (UE).

14. The AMF according to claim 13, wherein The unavailability type indicates the reason for unavailability due to discontinuous coverage.

15. The AMF according to claim 13, wherein The at least one processor is further configured to: When the power saving parameter is requested from the UE, the power saving parameter is determined based on the unavailable period duration.

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