Method and apparatus for non-terrestrial network mobility in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Disclosed herein is a method of a user equipment (UE) for a non-terrestrial network (NTN), the method comprising: receiving, from a network, assistance information for cell reselection related to the non-terrestrial network (NTN); and performing measurements on the neighboring cells for cell reselection based on the auxiliary information, where the auxiliary information includes ephemeris information about the neighboring cells. In an embodiment, the assistance information is included in a system information block (SIB) broadcasted by at least one of a serving cell and a neighbor cell.

Description

Technical Field

[0001] The present disclosure relates to enhancements to non-terrestrial network mobility in a 5G New Radio (NR) system, and more particularly to methods and apparatus for providing enhancements to non-terrestrial network mobility in a 5G NR system. Background Art

[0002] 5G mobile communication technology defines a wide frequency band so that high transmission rates and new services are possible, and can be realized not only in "below 6 GHz" frequency bands such as 3.5 GHz, but also in "above 6 GHz" frequency bands called millimeter waves including 28 GHz and 39 GHz. In addition, it has been considered to implement 6G mobile communication technology (called super 5G system) in terahertz frequency bands (e.g., 95 GHz to 3 THz frequency bands) in order to achieve a transmission rate fifty times faster than 5G mobile communication technology and an ultra-low latency one-tenth of 5G mobile communication technology.

[0003] At the beginning of the development of 5G mobile communication technology, in order to support services and meet performance requirements related to enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and massive machine type communication (mMTC), there has been ongoing standardization on the following aspects: beamforming and massive MIMO for mitigating radio wave path loss in millimeter waves and increasing radio wave transmission distance, dynamic operation of parameter sets (e.g., operating multiple subcarrier spacings) and time slot formats to support efficient utilization of millimeter wave resources, 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-scale data transmission and polar codes for highly reliable transmission of control information, L2 preprocessing, and network slicing for providing dedicated networks customized for specific services.

[0004] Currently, there are ongoing discussions on improvements and performance enhancements to initial 5G mobile communication technologies in view of the services they are to support, and there has been physical layer standardization on technologies such as: V2X (Vehicle-to-Everything) for assisting driving decisions of autonomous vehicles based on information about the location and status of a vehicle sent by the vehicle and for enhancing user convenience, NR-U (Unlicensed New Radio) for system operation designed to comply with various regulatory-related requirements within unlicensed frequency bands, NR UE energy saving, non-terrestrial networks (NTNs) as UE-satellite direct communication for providing coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0005] In addition, in the air interface architecture / protocol, there is already ongoing standardization on technologies such as the Industrial Internet of Things (IIoT) that supports new services through interconnection and convergence with other industries, IAB (Integrated Access and Backhaul) that provides 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 (two-step RACH for NR) for simplifying the random access process. Standardization is also ongoing in terms of system architecture / services: a 5G baseline architecture (e.g., a service-based architecture or a service-based interface) for combining network function virtualization (NFV) and software defined network (SDN) technologies, and mobile edge computing (MEC) for receiving services based on UE location.

[0006] As 5G mobile communication systems are commercialized, the number of connected devices, which has been growing exponentially, will be connected to the communication network, and it is expected that enhanced functions and performance of the 5G mobile communication systems and integrated operations of the connected devices will be necessary. To this end, new research is arranged on extended reality (XR) for effectively supporting AR (augmented reality), VR (virtual reality), MR (mixed reality), etc., 5G performance improvement and complexity reduction by utilizing artificial intelligence (AI) and machine learning (ML), AI service support, metaverse service support, and drone communication.

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

[0008] Wireless or mobile (cellular) communication networks, in which mobile terminals (UEs, such as mobile handsets) communicate via radio links with a network of base stations or other wireless access points or nodes, have undergone rapid development over several generations. The 3rd Generation Partnership Project (3GPP) designs, specifies and standardizes technologies for mobile wireless communication networks. Fourth (4G) and fifth (5G) generation systems are now widely deployed.

[0009] The 3GPP standard for 4G systems includes the Evolved Packet Core (EPC) and Enhanced UTRAN (E-UTRAN: Enhanced Universal Terrestrial Radio Access Network). E-UTRAN uses Long Term Evolution (LTE) radio technology. LTE is generally used to indicate the entire system including both EPC and E-UTRAN, and LTE is used in this sense in the rest of this document. LTE should also be considered to include LTE enhancements, such as LTE Advanced and LTE Pro, which provide enhanced data rates compared to LTE.

[0010] In 5G systems, a new air interface has been developed, which may be referred to as 5G New Radio (5GNR) or simply NR. NR is designed to support a wide variety of services and use case scenarios envisioned for 5G networks, despite being built on established LTE technology. New frameworks and architectures are also being developed as part of 5G networks in order to increase the range of functionality and use cases available through 5G networks. One such new architecture focuses on the use of non-terrestrial networks (NTNs) as part of the radio access network (RAN). NTNs include the provision of RANs via satellites, and may also include high altitude platforms and air-to-ground (ATG) scenarios. However, the use of NTNs, particularly when provided via satellites, presents many challenges regarding cell selection and reselection, as well as mobility between NTNs and between NTNs and terrestrial networks (TNs).

[0011] According to 3GPP TS 38.300, the non-terrestrial network (NTN) provides NTN New Radio (NR) access to the user equipment (UE) through the NTN payload, the NTN gateway, the service link between the NTN payload and the UE, and the feeder link between the NTN gateway and the NTN payload. Three types of service links are supported:

[0012] Geofixed: provided by a beam (or multiple beams) that always continuously cover the same geographical area (e.g., the case of geostationary orbit (GSO) satellites)

[0013] Quasi-geo-fixed: provided by a beam (or beams) that cover one geographical area for a limited period of time and a different geographical area for another period of time (e.g., the case of a non-GSO (NGSO) satellite generating a steerable beam)

[0014] Geomobile: provided by a beam (or multiple beams) whose coverage area slides over the surface of the Earth (e.g., the case of NGSO satellites generating fixed or non-steerable beams)

[0015] Utilizing NGSO satellites, 5G NR base stations (i.e., gNBs) can provide quasi-geo-fixed cell coverage or geo-mobile cell coverage, while gNBs operated using GSO satellites can provide geo-fixed cell coverage. However, the use of NGSO satellites presents particular challenges due to the non-geo-fixed cell coverage, i.e., due to the mobile nature of the cells provided by NGSO satellites.

[0016] Regarding mobility in RRC_IDLE and RRC_INACTIVE modes, the network may broadcast multiple Tracking Area Codes (TACs) per PLMN in the NR NTN cell. The TAC change in the System Information (SI) is under network control, i.e., it may not be precisely synchronized with the real-time illumination of the beam on the ground. In addition, the NTN ephemeris is divided into satellite ephemeris of the serving cell and satellite ephemeris of the neighboring cells.

[0017] Regarding UE measurements and NTN, the UE may report the serving link propagation delay difference between the serving cell and the neighboring cell as auxiliary information for adjusting the synchronization signal block (SSB) based radio resource management (RRM) measurement time configuration in connected mode.

[0018] In the quasi-geo-fixed cell scenario, the UE can perform time-based and location-based measurements in RRC_IDLE / RRC_INACTIVE, where:

[0019] Timing and location information associated with a cell is provided via system information

[0020] The timing information indicates the time when the serving cell will stop serving the geographic area.

[0021] The location information indicates the reference location of the serving cell

[0022] The measurement rules for cell reselection with timing information and location information are specified in section 5.2.4.2 of 3GPP TS 38.304 v17.1.0, where this is reproduced below and the definitions of terms can be found in this document.

[0023]

Table 1

[0024]

[0025]

[0026] In view of the above, enhancements to Next Generation (NG)-RAN based NTN are sought based on the following assumptions with implicit compatibility to support HAPS (High Altitude Platform Station) and ATG (Air-to-Ground) scenarios:

[0027] GSO (Geosynchronous Orbit) and NGSO (Non-Geosynchronous Orbit). NGSO includes Low Earth Orbit (LEO) and Medium Earth Orbit (MEO).

[0028] Geofixed Tracking Area. Geofixed and geomobile cells for NGSO.

[0029] FDD mode.

[0030] UE with GNSS (Global Navigation Satellite System) capabilities.

[0031] In particular, enhancements to NTN-TN and NTN-NTN measurements / mobility and service continuity are sought, including:

[0032] I) For NTN-NTN mobility, cell reselection enhancements for geo-mobile cells are specified. The timing-based and location-based cell reselection for quasi-geo-fixed cells in Rel-17 (3GPP TS 38.304 v17.1.0) can be considered as a starting point.

[0033] II) Specifies NTN-NTN handover enhancements for RRC_CONNECTED UEs in quasi-geo-fixed cells and geo-mobile cells to reduce signaling overhead.

[0034] III) Specify cell reselection enhancement for RRC_IDLE / INACTIVE UEs to reduce UE power consumption (NTN-TN mobility is prioritized).

[0035] IV) Specifies enhancements to Xn[ / NG] signaling to support feeder link handover, CHO, e.g. exchange of information between gNBs.

[0036] The present disclosure focuses on providing enhancements related to I)-III) above.

[0037] The contents of the following documents are cited below and / or their contents provide useful background information which should be considered in context of the following disclosure.

[0038] RP-221819, Revised WID: NR NTN (Non-Terrestrial Network) Enhancements,

[0039] R2-2206509, Correction to Phase 2 of NR NTN

[0040] 3GPP TS 38.413v17.1.1, Technical Specification Group Radio Access Network; NG-RAN; NG Application Protocol (NGAP)

[0041] 3GPP TS 38.331v17.1.0, Technical Specification Group Radio Access Network; NR; Radio Resource Control (RRC) Protocol Specification

[0042] 3GPP TS23.501v 17.5.0 Summary of the invention

[0043] Technical issues

[0044] Certain examples of the present disclosure are directed to providing enhancements to cell selection / reselection for non-terrestrial networks (NTNs) and / or reducing signaling overhead and power consumption involving cell selection / reselection for NTNs.

[0045] The invention is defined in the independent claim. Advantageous features are defined in the dependent claims.

[0046] Therefore, an embodiment of the present invention provides a method for a user equipment (UE) of a non-terrestrial network (NTN), the method comprising: receiving auxiliary information for cell reselection related to the non-terrestrial network (NTN) from a network; and performing measurements on neighboring cells for cell reselection based on the auxiliary information, wherein the auxiliary information includes ephemeris information about the neighboring cells. In an embodiment, the auxiliary information is included in a system information block (SIB) broadcasted by at least one of a serving cell and a neighboring cell.

[0047] In an embodiment, the UE receives a system information block (SIB) from a network, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0048] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0049] Therefore, an embodiment of the present invention provides a method of a network entity, the method comprising: sending auxiliary information related to a non-terrestrial network (NTN) for cell reselection to a user equipment (UE); wherein the auxiliary information is used to perform measurements on neighboring cells for cell reselection, and wherein the auxiliary information includes ephemeris information about the neighboring cells.

[0050] In an embodiment, the assistance information is included in a system information block (SIB) broadcast by at least one of the serving cell and the neighboring cell.

[0051] In an embodiment, the network entity sends a system information block (SIB) to the UE, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0052] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0053] Therefore, an embodiment of the present invention provides a user equipment (UE) for a non-terrestrial network (NTN), the UE comprising: a transmitter; a receiver; and at least one processor, coupled to the transmitter and the receiver, and configured to: receive auxiliary information for cell reselection related to the non-terrestrial network (NTN) from a network, and perform measurements on neighboring cells for cell reselection based on the auxiliary information, wherein the auxiliary information includes ephemeris information about the neighboring cells.

[0054] In an embodiment, the assistance information is included in a system information block (SIB) broadcast by at least one of the serving cell and the neighboring cell.

[0055] In an embodiment, at least one processor is configured to receive a system information block (SIB) from a network, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0056] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0057] Therefore, an embodiment of the present invention provides a network entity, the network entity comprising: a transmitter; a receiver; and at least one processor, coupled to the transmitter and the receiver, and configured to: send auxiliary information for cell reselection related to a non-terrestrial network (NTN) to a user equipment (UE), wherein the auxiliary information is used to perform measurements on neighboring cells for cell reselection, and wherein the auxiliary information includes ephemeris information about the neighboring cells.

[0058] In an embodiment, the assistance information is included in a system information block (SIB) broadcast by at least one of the serving cell and the neighboring cell.

[0059] In an embodiment, at least one processor is configured to send a system information block (SIB) to a UE, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0060] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0061] Before proceeding to the following detailed description, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising" and their derivatives are meant to include, but are not limited to; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with" and their derivatives may mean include, be included within, interconnected with, contain, be contained within, connect to or be connected with, be coupled to or be coupled with, be communicative with, cooperate with, interleave, juxtapose, be proximate to, be bound to or be bound with, have, have the property of, etc.; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two thereof. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0062] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or a portion thereof suitable for implementation in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disk (DVD) or any other type of memory. "Non-transitory" computer-readable media excludes wired, wireless, optical or other communication links that transmit temporary electrical signals or other signals. Non-transitory computer-readable media include media in which data can be permanently stored and media in which data can be stored and rewritten later, such as rewritable optical disks or erasable memory devices.

[0063] Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts:

[0065] Figure 1a and 1b A schematic diagram showing a UE NTN capability message and its content according to the present disclosure.

[0066] Figure 2 A schematic diagram showing a UE NTN capability message and its content according to the present disclosure.

[0067] Figure 3a and 3b Schematic diagram showing an example NTN mobility scenario.

[0068] Figure 4 A schematic diagram illustrating network entities according to examples of the present disclosure. DETAILED DESCRIPTION

[0069] Figures 1 to 2 discussed below Figure 4 The various embodiments used to describe the principles of the present disclosure in this patent document are for illustration only and should not be interpreted in any way as limiting the scope of the present disclosure. Those skilled in the art will appreciate that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0070] Examples according to the present disclosure will now be described in the context of a 5G wireless communication network, which includes, for example, one or more mobile terminals, a RAN, and a core network. A 5G wireless communication network may also be considered to include a mobile terminal and a network, wherein the network includes one or more network entities forming a RAN and / or a core network (CN). However, it will be understood that the present disclosure is not limited to 5G systems, but may be applied to other wireless communication systems where satellite communications are available. Therefore, references to specific 3GPP constructions in certain examples should not be understood as limiting the ability of the examples of the present disclosure to be applied to other wireless communication networks. The methods set forth below and in the claims are applicable to the use of non-terrestrial networks in any form with any type of UE or a mix of UEs (such as, as an example, IoTNTN) as well as conventional UEs.

[0071] NGSOs (e.g., LEO satellites) move at very high speeds (e.g., over 20,000 km / h), so it is expected that the service links (e.g., earth mobile cells) will move at the same high speed as the satellites. This may result in discontinuous user equipment (UE) coverage in New Radio (NR) Non-Terrestrial Networks (NTNs). In addition, other parameters (e.g., UE speed, location, trajectory, and / or elevation / altitude or others) may further increase coverage issues in NR NTNs. As a result, the following problems may occur:

[0072] Measurement failure: Due to the mobility of the UE and the desired cell, the UE may not be able to perform measurements (e.g., cell selection, cell reselection) on the serving and / or neighboring cells.

[0073] Handover failure: Currently, handover decisions are based on trigger thresholds of received signal quality of the target (handover to) cell (i.e., cell selection criteria S and reselection criteria R). However, this approach will lead to a high handover failure rate due to the increased probability of handover interruption (i.e., handover incomplete) due to cell movement and UE leaving coverage during the handover process.

[0074] Given these potential issues, one or more of the following areas should be addressed.

[0075] 1) How to implement NTN-NTN mobility including cell reselection enhancement for earth mobile cells?

[0076] 2) How to perform cell reselection (ie including measurements) taking into account UE type and / or serving link capabilities?

[0077] 3) How to perform cell reselection (ie including measurements) taking into account UE mobility and satellite mobility?

[0078] 4) How to specify cell reselection enhancement for RRC_IDLE / INACTIVE UEs to reduce UE power consumption (NTN-TN mobility is prioritized)?

[0079] Unless stated to be incompatible, the examples and / or functions set forth below may be configured individually or in combination. Therefore, although various examples are described individually, they should not be interpreted as separate embodiments that cannot be combined.

[0080] According to the present disclosure, a UE may be configured with different cell selection / reselection parameters and / or candidate / available NTN cells based on the type of cell (i.e., service link type), the availability of the cell relative to the UE, the location and / or mobility of the UE and the cell, and / or the capabilities of the UE (e.g., the type of service link supported). Information about the type of NTN cell may be provided to the UE by each cell (e.g., via broadcast system information signaling and / or dedicated RRC messages), may be preconfigured at the UE, or may be provided via an existing network connection (e.g., via the current serving cell). Information about the cell type includes information about the serving cell and / or neighboring cells, and may, for example, specify whether the cell is one or more of an earth mobile, quasi-earth fixed, or earth fixed cell. Other information on which the cell selection / reselection may be based may be preconfigured or received from the network or an entity thereof, the cell itself, the serving cell (i.e., the serving gNB), or calculated by the UE. Throughout the present disclosure, although sometimes only cell selection may be mentioned, this includes both (initial) cell selection and cell reselection.

[0081] NTN Cell List

[0082] In the first method, one or more cell lists on which cell reselection may occur are configured at the UE, wherein the cell list may be configured by the network or its entities (e.g., gNB, AMF, other network entities) or by the UE itself based on obtained cell information.

[0083] When configured by the network or an entity thereof, the network may configure a list of NTN and / or TN cells suitable for UE measurement and / or cell (re)selection capabilities (e.g., for cell reselection) based on one or more of the cell type (e.g., TN, NTN geo-fixed, NTN quasi-geo-fixed, NTN geo-mobile), UE type (i.e., category), and serving link capabilities (e.g., TN, NTN geo-fixed, NTN quasi-geo-fixed, NTN geo-mobile). The capabilities of the UE may have been previously reported to the network, wherein such capability reporting is described in more detail below. With respect to the type / content of the list, the network (e.g., gNB) may, for example, configure one or more of the following:

[0084] An allowed cell list (e.g., NTN Earth Fixed and / or NTN Quasi Earth Fixed, TN) for UEs that can perform normal measurements and / or cell (re)selection and / or handover. In one example, an allowed cell list may be provided for each cell type (e.g., TN, NTN Earth Fixed, NTN Quasi Earth Fixed, NTN Earth Mobile, etc.). In another embodiment, the allowed cell list contains the physical cell IDs (PCIs) of the allowed neighboring cells.

[0085] A forbidden cell list (e.g., NTN Earth Mobile) for UEs that are not capable of performing fast measurements and / or cell (re)selection and / or handover to Earth Mobile cells. In one example, a forbidden cell list may be provided for each cell type (e.g., TN, NTN Earth Fixed, NTN Quasi-Earth Fixed, NTN Earth Mobile). In another example, the forbidden cell list contains the PCIs of forbidden neighboring cells.

[0086] A list of neighboring cells and their types (e.g., TN, NTN Earth Mobile, NTN Earth Fixed, or NTN Quasi Earth Fixed). An indication may be provided to the UE that the cell belongs to an Earth Mobile cell type, or a list of cells indicating that the cell belongs to an Earth Fixed or Quasi Earth Fixed cell type may be provided. In one example, the cell list contains the PCIs of the neighboring cells and the serving cell. In another example, the cell type of the NTN cell is identified by the ephemeris provided in the system information (e.g., SIB19) and / or dedicated signaling.

[0087] The gNB may provide the above lists on a per-frequency basis in broadcast signaling and / or dedicated signaling. In some examples, an indication that all available cells may be considered for selection / reselection may be provided instead of a list, for example, if the capabilities of the UE do not result in limitations (e.g., when the UE supports earth mobile cells). Each of the cell lists described above may also be based at least in part on other selection criteria, such as based on the priority or load of the cell.

[0088] The UE may consider neighboring cells for reselection (i.e., perform measurements for cell reselection or perform cell reselection evaluation) based on one or more of the above lists. The UE's consideration of cells may be limited to the list, or if the list has not been formed based on criteria related to the UE, the UE's consideration of cells may be further reduced. For example, the UE may consider neighboring cells for reselection based on the type of cell, so that if the UE cannot camp on an earth mobile cell, the UE may not reselect to a neighboring cell indicated as an earth mobile cell.

[0089] In another example, the UE may apply different types of cell reselection based on the configured list. For example, if the type of the cell is an earth mobile cell, the UE may perform normal cell reselection (e.g., cell reselection not specific to NTN) and may not perform distance and location based cell reselection. In another example, the network may inform the UE of the type of cell reselection possible for a specific type of cell and a specific type of UE.

[0090] In addition to the identification of cells and / or their types in the above detailed list, the network may also provide any of the following further information to the UE in such a list on a serving cell, neighboring cell and / or per cell or cell group basis. However, this additional information may also be provided in system information or via other mechanisms.

[0091] Timer(s) indicating the time at which a cell will appear (ie become available for measurement and / or serving). This information about neighboring cells may be provided by the serving cell through a system information message (eg included in SIB19, t-Appear).

[0092] Timer(s) indicating the time at which a cell will disappear (ie become unsuitable for measurement and / or service). This information about neighbor cells and serving cells may be provided by the serving cell through system information messages (eg included in SIB19, t-Disappear).

[0093] The velocity and / or trajectory of the serving cell and neighboring cells (e.g., cellVelocity, cellTrajectory)

[0094] The current locations of the serving cell and neighboring cells (eg, cell reference points and / or others).

[0095] If the network does not provide a timer and only provides location and speed, the UE can calculate the timer for appearance and disappearance from the speed and location. Similarly, if the time of appearance and / or disappearance is provided, the UE can calculate the cell speed.

[0096] In some examples, based on the above information, the relative speed between the UE and the earth mobile cell will be used by the UE to calculate the position / timing for applying timing-based and / or position-based cell reselection.

[0097] For example, if distanceThresh is broadcasted in SIB19, and if the UE supports location-based measurement initiation for NTN earth mobile cells and has valid UE location information, then for NTN earth mobile cells, the UE can use the relative speed between the UE and the earth mobile cell to calculate the distance between the cell and the UE. If the distance is higher than distanceThresh, the UE can perform intra-frequency measurements. If the distance is higher than distanceThresh and the serving cell satisfies Srxlev>SnonIntraSearchP and Squal>SnonIntraSearchQ, the UE can perform inter-frequency measurements of equal or lower priority.

[0098] In another example, if the UE is moving away from the NTN quasi-earth fixed low priority neighbor or the NTN earth mobile low priority neighbor cell is moving away from the UE, or the UE and the NTN low priority neighbor earth mobile cell and the UE are moving away from each other and the neighbor cell has not met the neighbor cell reselection evaluation criteria in Section 5.2.4.5 of TS 38.304v17.1.0 (Squal>ThreshX,LowQ or Srxlev>ThreshX,LowP, as appropriate), the UE may not perform cell reselection measurements for the cell. If there is an allowedlist broadcast as described above, and it is not necessary to measure all cells as mentioned above, the UE may not perform cell reselection measurements for the frequency.

[0099] As mentioned above, the UE may support location-based measurement initiation for NTN geo-fixed, NTN quasi-geo-fixed, but not for NTN geo-mobile cells, so the list may be configured accordingly. The UE may indicate its capabilities to the network in RRC signaling.

[0100] The speed of the earth mobile cell may be used to determine the mobility state of the UE for performing cell reselection measurements and evaluations. Alternatively, the relative speed between the UE and the earth mobile cell may be used to determine the mobility state of the UE for performing cell reselection measurements and evaluations.

[0101] The network may also include the following information in the above detailed list on a serving cell, neighboring cell and / or per cell or cell group basis, where this information may be used to determine the mobility information of the UE and to perform cell reselection measurements and evaluations. This additional information may also be provided in system information or via other mechanisms.

[0102] Satellite (e.g., beam, cell) mobility characteristics / parameters (e.g., speed, direction or movement, elevation angle, altitude, other)

[0103] All of the above information may be provided to the UE via dedicated signaling and / or system information broadcast (eg, periodically and / or on-demand).

[0104] When the same frequency is used by an earth mobile cell and other NTN cells (i.e., earth fixed cells, quasi-earth fixed cells, etc.) or TN cells, different cell reselection thresholds (e.g., for reference signal received power / reference signal received quality / received signal strength indicator (RSRP / RSRQ / RSSI)) may be used for earth mobile cells within the same frequency, where these thresholds may be added, for example, in a cell list. In some cases, a scaling factor may be provided to the UE for the earth mobile cell, and the UE applies the scaling factor to the measurement. For example, a scaling factor may be provided for Treselection of the earth mobile cell. Alternatively, different values ​​of Treselection (Treselection–earthmoving) may be provided for the earth mobile cell. The UE applies Treselection+scaling factor or Treselection-earthromoving to the earth mobile cell. For other cells in the same frequency, the UE may not apply the scaling factor depending on their type and / or service link type.

[0105] In some examples, each type of cell may be associated with a different threshold and a different offset. For example, earth mobile cells may have different thresholds and offsets for low priority, equal priority, high priority reselection, etc., compared to other types. Similarly for other types. In other examples, for distance-based cell reselection, the distance threshold for each type of cell may be different.

[0106] In some examples, the network may request information about UE mobility (e.g., velocity, acceleration, trajectory, elevation, altitude, and / or other information) using, for example, a UEInformationRequest message, where the UEInformationRequest message may include, for example, fields velocityRequest-r18, travelryRequest-r18, and / or altitudeRequest-r18. Details of the UEInformationRequest message are set forth below. This information may be used by the network to configure a list or other cell selection / reselection parameters.

[0107] UEInformationRequest message

[0108]

[0109] velocityRequest-r18

[0110] This field is used to request the UE to report its speed information.

[0111] trajectoryRequest-r18

[0112] This field is used to request the UE to report its trajectory information.

[0113] altitudeRequest-r18

[0114] This field is used to request the UE to report its altitude information.

[0115] Furthermore, the UE may use the UEInformationResponse message to report its mobility information to the network, the details of which are described below.

[0116]

[0117] As described above, satellite information (eg, satellite assistance information) may be provided in a SIB19 information element, details of which are set forth below. The assistance information may also include cell location information (eg, current location and / or cell reference point).

[0118]

[0119]

[0120]

[0121] UE Capability Report

[0122] In order to configure the above-described list by the network, the network may obtain information about the NTN capability of the UE so as to appropriately determine the cells that can be selected by the UE and on which measurements can be performed. The method for providing UE capability information to the network includes

[0123] UE capabilities for NTN operation may be defined and / or reported as generic NTN capabilities. For example, a UE may report that it is capable of NTN operation.

[0124] UE capabilities for NTN operation may be defined and / or reported in terms of service link type (e.g., geo-fixed, quasi-geo-fixed, and / or geo-mobile) and NTN capabilities (e.g., service link capabilities or other nomenclature). For example, a UE may report the service link type(s) of NTN it supports.

[0125] The UE may include this information in the UE capability response. The network (e.g., gNB) may configure dedicated cell reselection information for the UE based on the UE NTN capability and service link type capability and / or information related to UE mobility. The NTN capability information may also be reported periodically or if / when it changes, for example, when the NTN capability or a specific service link capability is enabled / disabled at the UE.

[0126] More generally, the UE may indicate its NTN capabilities and / or service link capabilities to the network directly to the CN or via the NG-RAN. For example, the UE may indicate its NTN capabilities and / or service link capabilities directly to the CN, for example, using existing and / or newly defined NAS signaling / messages. The CN may forward this information to the NG-RAN (e.g., via existing and / or newly defined NG signaling / messages), or the NG-RAN may retrieve the information from the CN (e.g., via existing and / or newly defined NG signaling / messages).

[0127] Alternatively, the NG-RAN may receive information related to the UE NTN capability and / or service link capability from the UE via RRC signaling / message (using existing and / or newly defined signaling / message). The UE may provide this information to the NG-RAN using existing or newly defined IEs (e.g., UE NTN capability IE, UE service link capability indication IE, or another naming) included in the RRC signaling / message. The NG-RAN may send / forward this information to the CN (e.g., AMF) using, for example, a UE radio capability information indication message, such as Figure 1a and Figure 1b , where additions to the message, such as new information elements (IEs), are underlined.

[0128] Alternatively, newly defined RRC and / or NG signaling / messages may be used, such as Figure 2 As shown, the UE is providing the network (NG-RAN and / or CN) with information about the UE NTN capability indication and / or the UE NTN service link capability indication included in existing or newly defined RRC and NG signaling / messages.

[0129] Other aspects of UE cell list processing

[0130] In some examples, a list of all NTN cells that the UE can measure and / or perform cell (re)selection may be provided by the network to the UE, wherein the list may be based on the UE type and / or serving link capability as set forth above, such that it may include information about cell type (i.e., serving link type), speed, timer, etc. Alternatively, the list may include only all available cells, without considering UE capabilities. The UE may then decide which cells to measure, taking into account NTN cell conditions (serving link type and / or mobility characteristics, others) and UE capabilities (i.e., serving link capabilities) and / or other conditions / scenarios (e.g., UE speed, trajectory, altitude, others). The speed type may also include NR NTN cell (serving link) speed, which is the speed of the mobile satellite coverage (e.g., beam, cell). That is, different UEs will measure different NTN cells and perform cell (re)selection accordingly, even though they may receive the same cell list.

[0131] In another example, the network is configured not to provide the UE with any of the NTN lists described above or the NTN list is not received by the UE and / or the network does not provide the UE with cell mobility characteristics and / or timing information of the NR NTN cell. In such a case, the UE may attempt to perform measurements and / or cell (re)selection for all NR NTN cells. For example, the UE considers UE NTN capabilities (e.g., service link capability = earth mobile) and NTN cell type (i.e., quasi-earth mobile and / or earth mobile), and / or other UE mobility conditions to perform measurements and / or cell reselection evaluation. In another example, the UE performs measurements and / or cell reselection evaluation without considering UE NTN capabilities or UE mobility conditions (e.g., UE movement direction relative to cell movement, or other). This method can also be used as a backup solution, i.e., NTN cell information has not been received or insufficient information has not been received. In some examples, the UE selection / reselection behavior can be based on information received from each cell (e.g., in system information), such as service link and mobility parameters. The UE may also base the UE selection / reselection behavior on its mobility information or configuration, such as whether a specific NTN capability is enabled / disabled.

[0132] Given the above described dependence of the NTN list and UE behavior on the existence of the NTN cell list, the following is an example formal description of allowed and prohibited NTN lists and UE behavior.

[0133]

[0134]

[0135] Application in NTN enhancement

[0136] The approach set forth above may be used to address one or more of aspects 1) to 4) and thereby enhance NTN mobility and reselection, as described in detail below.

[0137] Regarding how to perform NTN-NTN mobility, including cell reselection enhancements for earth mobile cells, reporting UE capabilities to the network (e.g., RAN, CN, another internal and / or external network entity, and / or network function), providing additional cell information to the UE, and / or providing an NTN list, can be used to address this aspect.

[0138] In a first embodiment, an indication of UE NTN capabilities in terms of support for different NTN cell types as described above can be introduced to provide the network with UE capability information. Subsequently, based on the UE capability information and potentially further information (e.g., UE subscription information), the network can assign a suitable list of NTN cells to the UE in dedicated signaling, thereby enhancing NTN cell selection.

[0139] In a second embodiment, the UE can be provided with timing information about earth mobile cells (serving and / or neighboring cells), for example, the time when the cells appear and / or disappear from the UE coverage. The UE can then use the timing information and information about satellite speed, altitude, position, elevation angle, trajectory, etc. to decide the feasibility of measuring and / or reporting measurements of earth mobile cells. The selection criteria based on this information can be pre-configured or received from the network.

[0140] Alternatively or additionally, a network configuration list specifying allowed or forbidden cells may be used to address aspects of how to perform NTN-NTN mobility, including cell reselection enhancement for earth mobile cells.

[0141] For example, the network may configure a cell list suitable for UE NTN capabilities / types and / or UE conditions / scenarios (e.g., UE mobility, others). In particular, the network may allocate to the UE a list (one or more) of NR NTN cells of one or more service link types (i.e., earth-fixed, quasi-earth-fixed and / or earth-mobile NTN cells). For example, the list may be named "allowedNTNCellsList", "forbiddEntNCellsList" or other suitable names, and may be formed taking into account UE type information, so that the NW may allocate an allowedNTNCellsList including fixed and / or quasi-earth-fixed cells, and a forbiddenEntNCellsList including earth-mobile cells.

[0142] The first and second embodiments may also be used to enhance or prioritize TN-NTN and / or NTN-TN mobility. For example, the list may be configured to prioritize certain TN cells or NTN cells according to the current requirements of the network and / or UE. In other words, the various methods and embodiments described above may be applied to any aspect of mobility involving NTN.

[0143] Regarding how to perform cell reselection (i.e., including measurements) taking into account UE type and / or serving link capabilities, and how to perform cell reselection (i.e., including measurements) taking into account UE mobility and satellite mobility, these aspects can be addressed using a network configuration list. Appropriate configuration of the NTN selection / measurement process at the UE can also achieve these goals. For example, if a specific NTN cell has a specific type and / or its characteristics meet a specific threshold, then measurements on a specific NTN cell can be performed, where the threshold can be, for example, related to time, distance, or mobility.

[0144] For example, assuming that the network knows the UE NTN capability information (e.g., via using the capability report described previously), the network can configure the list (or multiple) provided to the UE based on the UE capabilities (i.e., UE type and / or serving link capabilities) and / or configure the list (or multiple) based on the UE mobility information and satellite mobility information. The list can then be provided in one or more of the forms described above, such as "allowedNTNCellsList", "forbiddenNTNCellsList".

[0145] Alternatively, the UE may utilize assistance information that has been provided from the network via system information broadcast and / or dedicated signaling in order to determine which NTN cells to consider for measurement after receiving a cell list or in the absence of a cell list.

[0146] Regarding how to specify cell reselection enhancement for RRC_IDLE / INACTIVE UEs to reduce UE power consumption (NTN-TN mobility is prioritized), the network can configure the list to prioritize TN over NTN. Alternatively, as described above, the configuration of priority sorting for certain TNs or NTNs can be performed unilaterally at the UE or in response to configuration information received from the network. This prioritization can also be implemented in response to network or UE requirements.

[0147] Example 3GPP Specification Modification

[0148] The following is an example of changes to 3GPP TS 38.304 V17.1.0 for adjusting UE measurement (i.e., selection / reselection) behavior relative to earth mobile NTN and implementing one or more of the enhancements described above, wherein the changes are underlined. In particular, the changes set forth below take into account the type of service links provided by the cell and the type of service links supported by the UE in order to reduce unnecessary measurements of the cell. In addition, information about cell mobility, timing, etc. that can be provided to the UE is also used to reduce unnecessary measurements of the cell, for example, if the coverage of the existing serving cell is not expected to stop within a certain time period, then measurements on neighboring cells may not be performed, or if the coverage of the neighboring cell is expected to stop within a certain time period, then measurements on the neighboring cell may not be performed. In addition, the cell list defined above and other timing information, auxiliary information, etc. may also be included in the measurement rules for cell reselection below, so that, for example, the NTN cells considered are limited to those included on the configured list.

[0149] Measurement rules for cell reselection

[0150] The UE uses the following rules to limit the measurements:

[0151] -If the serving cell satisfies Srxlev>SIntraSearchP and Squal>SIntraSearchQ:

[0152] - If distanceThresh is broadcasted in SIB19 and if the UE supports location based measurement start and has obtained its location information:

[0153] - If the service link type is Earth Fixed, and

[0154] - If the distance between the UE and the serving cell reference location is shorter than distanceThresh, the UE may not perform intra-frequency measurements;

[0155] - Otherwise, the UE shall perform intra-frequency measurements;

[0156] - Otherwise, the UE may not perform intra-frequency measurements;

[0157] - Otherwise, the UE shall perform intra-frequency measurements.

[0158] - If the serving link type is Quasi-Earth Fixed or Earth Mobile and the UE is capable of operating in a specific cell type:

[0159] If information about the serving cell's mobility (e.g., speed, direction of movement, and / or others) is broadcast in SIBxx (or as part of satellite ephemeris), and if the UE supports coverage time calculation and has obtained / calculated its remaining time in serving cell coverage (e.g., t-Coverage):

[0160] - If tCoverage is greater than timeMeasThresh, the UE may not perform intra-frequency measurements;

[0161] - Otherwise, the UE shall perform intra-frequency measurements;

[0162] - Otherwise, the UE may not perform intra-frequency measurements;

[0163] - Otherwise, the UE shall perform intra-frequency measurements.

[0164] - The UE shall apply the following rules to the NR inter-frequencies and inter-RAT frequencies indicated in the system information and for which the UE has provided priorities as defined in 5.2.4.1:

[0165] - For an NR inter-frequency or inter-RAT frequency with a reselection priority higher than the reselection priority of the current NR frequency, the UE shall perform measurements of the higher priority NR inter-frequency or inter-RAT frequency according to TS 38.133 [8].

[0166] - For inter-NR frequencies with equal or lower reselection priority than the current NR frequency and for inter-RAT frequencies with lower reselection priority than the current NR frequency:

[0167] - If the serving cell satisfies Srxlev>SnonIntraSearchP and Squal>SnonIntraSearchQ:

[0168] - If distanceThresh is broadcasted in SIB19 and if the UE supports location based measurement start and has valid UE location information:

[0169] - If the distance between the UE and the serving cell reference location is shorter than distanceThresh, the UE may choose not to perform measurements on NR inter-frequency cells of equal or lower priority, or lower priority inter-RAT frequency cells;

[0170] - Otherwise, the UE shall perform measurements on NR inter-frequency cells of equal or lower priority or on inter-RAT frequency cells of lower priority according to TS 38.133 [8];

[0171] - Otherwise, the UE may choose not to perform measurements on NR inter-frequency cells of equal or lower priority, or on inter-RAT frequency cells of lower priority;

[0172] Otherwise, the UE shall perform measurements on NR inter-frequency cells of equal or lower priority or on inter-RAT frequency cells of lower priority according to TS 38.133 [8].

[0173] - If the UE supports relaxed measurement and relaxedMeasurement is present in SIB2, the UE may further relax the measurement as specified in clause 5.2.4.9.

[0174] - If the service link type is geofixed or quasi-geofixed:

[0175] If there is t-Service for the serving cell in SIB19, the UE shall perform intra-frequency, inter-frequency or inter-RAT measurements before t-Service, regardless of the distance between the UE and the serving cell reference position or whether the serving cell satisfies Srxlev>SIntraSearchP and Squal>SIntraSearchQ, or Srxlev>SnonIntraSearchP and Squal>SnonIntraSearchQ, and the time to start measurement before t-Service depends on the UE implementation. The UE shall perform measurements of higher priority NR inter-frequency or inter-RAT frequencies according to TS 38.133 [8], regardless of the remaining service time of the serving cell (i.e., the remaining time until t-Service).

[0176] NOTE: When evaluating the distance between the UE and the serving cell reference location, it is up to the UE implementation to obtain the UE location information.

[0177] Note: For earth mobile cells, the UE should consider the relative speed between the UE and the cell and the relative distance between the UE and the cell.

[0178] - If the service link type is Earth Mobile

[0179] If tCoverage of the serving cell is present in SIBxx, the UE shall follow the above rules regarding measurements, regardless of t-Service of the serving cell or ... Otherwise, the UE follows the same behavior for the geo-fixed or quasi-geo-fixed cases.

[0180] Example NTN cell reselection and / or measurements

[0181] Figure 3a and Figure 3bExample scenarios are shown in which the proposed method may be applied, in particular procedures that a UE may perform in view of the example 3GPP specification modifications set out above.

[0182] exist Figure 3a In , the UE and the satellite have the same trajectory, and Figure 3b In both figures, the UE and the satellite have different trajectories. In both figures, the cell provided by the satellite is an earth moving cell, and the UE is located on an airplane. Therefore, there are problems with both earth moving cells and UE mobility.

[0183] exist Figure 3a and Figure 3b In both scenarios, the UE calculates the remaining coverage time for each Earth Mobile NTN cell using auxiliary information received from the network (e.g., cell speed, cell direction, cell size, cell altitude, cell trajectory, others and knowledge of its position, speed, altitude and / or moving direction, or other parameters related to the UE). Figure 3a and Figure 3b The identities of the cells and their types may be indicated in the received list, and the UE may determine the neighboring cells and their types based on information received from each neighboring cell or via information included in broadcast information from one or more cells (e.g., serving cells). The UE may calculate the cell remaining time in coverage for each cell (relative to the UE) as follows:

[0184]

[0185] where relativeDistance is the difference between the UE position and the position of the reference point / position in the cell, and relativeSpeed ​​is the difference between the satellite speed and the UE speed. Note that when calculating relativeSpeed, the trajectory of the UE relative to the satellite should be taken into account.

[0186] The UE calculates tCoverage and decides whether to perform measurements and / or cell reselection for each NTN cell. For example, for each NTN cell, the UE compares tCoverage with a given timeMeasThresh. timeMeasThresh is provided to the UE by the network (e.g., broadcast in a new SIB or an existing SIB (e.g., SIB19), or broadcast via dedicated signaling / messages).

[0187] If the UE receives timeMeasThresh and the UE supports time-based measurements for NTN cells (e.g., terrestrial mobile cells), the UE calculates tCoverage for this cell (as in the equation above). If the remaining time of the cell in coverage is higher than timeMeasThresh, the UE performs the measurement (and / or performs cell (re)selection). Otherwise, the UE may not perform the measurement (and / or perform cell (re)selection) for this cell.

[0188] Specifically regarding Figure 3a , the following method can be used.

[0189] At time T1, the UE (aircraft) is served by terrestrial mobile cell ID#X1.

[0190] The UE can perform measurements on adjacent terrestrial mobile cells for potential cell reselection.

[0191] Before performing the measurement (and / or performing cell (re)selection), considering the coverage time of each cell and the UE serving link capabilities (i.e., NTN cell type), and / or other auxiliary information that the UE may have obtained from the network, the UE checks whether it has enough time to perform the measurement (and / or perform cell (re)selection).

[0192] The UE calculates tCoverage for cells ID#X2, X3, X4 at time T2:

[0193] It is expected that cell ID#X2 has tCoverage < timeMeasThresh, while

[0194] it is expected that cells ID#X3 and X4 have tCoverage ≥ timeMeasThresh.

[0195] The UE can perform measurements and / or cell reselection on cell ID#X3 or #Y4.

[0196] Specifically regarding Figure 3b , the following method can be used.

[0197] At time T1, the UE (aircraft) is served by terrestrial mobile cell ID#X1.

[0198] The UE can perform measurements on adjacent terrestrial mobile cells for potential cell reselection.

[0199] Before performing measurements (and / or performing cell (re)selection), the UE checks whether it has enough time to perform measurements (and / or perform cell (re)selection), taking into account the remaining coverage time of each cell and the UE serving link capability (i.e., NTN cell type), and / or other auxiliary information that the UE may have obtained from the NW.

[0200] The UE calculates tCoverage for cell IDs #X2, X3 and X4 at time T2:

[0201] Cell ID #X2 and #X3 are expected to have tCoverage <timeMeasThresh。

[0202] Cell ID #X4 is expected to have tCoverage ≥ timeMeasThresh.

[0203] The UE decides to perform measurement and / or cell reselection on cell ID #X4.

[0204] A UE arranged to operate according to any of the examples of the present disclosure described above includes: a transmitter arranged to send signals to one or more RANs (including but not limited to satellite networks and 3GPP RANs, such as 5G NR networks); a receiver arranged to receive signals from one or more RANs and other UEs; and a controller arranged to control the transmitter and the receiver and perform processing according to the methods described above. The transmitter, the receiver, and the controller may be separate elements, but any single element or multiple elements providing equivalent functionality may be used to implement the examples of the present disclosure described above.

[0205] Figure 4 A block diagram showing exemplary network entities that may be used in examples of the present disclosure. For example, an entity of a UE, a core network, or a RAN (e.g., an eNB, a gNB, or a satellite) may be configured as Figure 4 Those skilled in the art will recognize that the network entity may be implemented as, for example, a network element on dedicated hardware, a software instance running on dedicated hardware, and / or a virtualized function instantiated on an appropriate platform (e.g., on a cloud infrastructure).

[0206] The entity 400 includes a processor (or controller) 401, a transmitter 403, and a receiver 405. The receiver 405 is configured to receive one or more messages from one or more other network entities, such as described above. The transmitter 403 is configured to send one or more messages to one or more other network entities, such as described above. The processor 401 is configured to perform one or more operations, such as according to the above operations.

[0207] The technology described herein can be implemented using any appropriately configured device and / or system. Such a device and / or system can be configured to perform a method according to any aspect, embodiment, example or claim disclosed herein. Such a device may include one or more elements, such as one or more of a receiver, a transmitter, a transceiver, a processor, a controller, a module, a unit, etc., each of which is configured to perform one or more corresponding processes, operations and / or method steps for implementing the technology described herein. For example, the operation / function of X can be performed by a module (or X module) configured to perform X. One or more elements can be implemented in the form of hardware, software, or any combination of hardware and software.

[0208] Particular network entities may be implemented as network elements on dedicated hardware, as software instances running on dedicated hardware, and / or as virtualized functions instantiated on an appropriate platform (eg, on a cloud infrastructure).

[0209] It will be appreciated that examples of the present disclosure may be implemented in the form of hardware, software, or any combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile memory, such as a storage device like a ROM, whether erasable or rewritable, or in the form of a memory, such as, for example, RAM, a memory chip, device or integrated circuit, or on an optical or magnetically readable medium, such as, for example, a CD, DVD, disk or tape, etc.

[0210] It will be appreciated that storage devices and storage media are embodiments of machine-readable storage suitable for storing one or more programs including instructions, wherein the instructions, when executed, implement certain examples of the present disclosure. Therefore, certain examples provide a program including code for implementing a method, apparatus, or system according to any example, embodiment, aspect, and / or claim disclosed herein, and / or a machine-readable storage storing such a program. Further, such a program may be transmitted electronically via any medium, such as a communication signal carried by a wired or wireless connection.

[0211] Throughout the description and claims of this specification, the words "comprise" and "comprising" and their variations mean "including but not limited to", and they are not intended to (and do not) exclude other components, integers or steps. Throughout the description and claims of this specification, the singular includes the plural, unless the context requires otherwise. In particular, where the indefinite article is used, the specification should be understood to contemplate the plural as well as the singular, unless the context requires otherwise.

[0212] Features, integers or characteristics described in conjunction with a particular aspect, embodiment or example of the present disclosure are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All features disclosed in this specification (including any accompanying claims, abstract and drawings) and / or all steps of any method or process so disclosed may be combined in any combination, except for at least some mutually exclusive combinations of such features and / or steps. The present disclosure is not limited to the details of any foregoing embodiments. Examples of the present disclosure extend to any novel one or any novel combination of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one or any novel combination of the steps of any method or process so disclosed.

[0213] The reader is advised to pay attention to all papers and documents related to the present application which are filed concurrently with or before the present specification, which are disclosed to the public with the present specification, and the contents of all these papers and documents are incorporated herein by reference.

[0214] The above embodiments should be understood as illustrative examples of the present disclosure. Further embodiments are contemplated. It should be understood that any feature described with respect to any one embodiment may be used alone or in combination with other features described, and may also be used in combination with one or more features of any other embodiment, or in combination with any combination of any other embodiment. In addition, equivalents and modifications not described above may also be used without departing from the scope of the present invention, which is defined in any appended claims.

[0215] Further examples according to the present disclosure are set forth in the following numbered clauses.

[0216] 1. A method for a mobile terminal of a non-terrestrial network (NTN) cell in a 5G new radio (NR) mobile communication system, the method comprising:

[0217] determining whether an NTN cell list has been configured at the mobile terminal; and

[0218] If an NTN cell list has been configured at the mobile terminal, NTN cell selection (ie, cell measurement) is performed based on the NTN cell list.

[0219] 2. A method according to clause 1, wherein the method further comprises sending NTN capability information of the mobile terminal from the mobile terminal to a network (e.g., a RAN entity, a core network or other network entity), and wherein the NTN cell list is determined based on the NTN capability information.

[0220] 3. A method according to any preceding clause, wherein the NTN cell list is received by the mobile terminal from the network.

[0221] 4. A method according to any preceding clause, wherein the NTN cell list comprises one or more NTN cells based on which the mobile terminal is allowed to perform NTN cell selection, or one or more NTN cells based on which the mobile terminal is not allowed to perform NTN cell selection.

[0222] 5. A method according to any one of clauses 1 to 3, wherein the NTN cell list includes one or more available NTN cells, and the method further comprises selecting an NTN cell among the available NTN cells on which to perform NTN cell selection based on a serving link capability of the mobile terminal and a type of the available NTN cells, and performing NTN cell selection based on the selected NTN cell.

[0223] 6. A method according to any preceding clause, wherein, if a list of NTN cells has not been configured at the mobile terminal, NTN cell selection is performed based on all available NTN cells.

[0224] 7. A method according to any of clauses 1 to 5, wherein if a list of NTN cells has not been configured at the mobile terminal, a cell on which NTN cell selection is to be performed is selected based on the serving link capability of the mobile terminal and the type of available NTN cells, and NTN cell selection is performed based on the selected NTN cell.

[0225] 8. A method according to any preceding clause, wherein the method further comprises receiving cell assistance information at the mobile terminal and selecting a cell on which to perform NTN cell selection based on the assistance information.

[0226] 9. A method as described in clause 8, wherein the cell assistance information comprises information about one or more of cell speed, cell direction, cell size, cell altitude and cell trajectory of the NTN cell.

[0227] 10. A method according to any preceding clause, wherein the method further comprises sending mobility information (e.g., speed, acceleration, trajectory, elevation angle, altitude and / or other information) of the mobile terminal to the network.

[0228] 11. A method according to clause 10, wherein the method further comprises receiving a request for mobility information of the mobile terminal from the network (e.g., a UEInformationRequest message), and sending the mobility information of the mobile terminal in response to the request (e.g., a UEInformationResponse).

[0229] 12. A method according to clause 10 or 11, wherein the NTN cell list is based on mobility information of the mobile terminal.

[0230] 13. A method according to any preceding clause, wherein the NTN cell is an Earth Mobile or Quasi Earth Fixed NTN cell.

[0231] 14. A method for a mobile terminal for non-terrestrial network (NTN) cell selection in a 5G new radio (NR) mobile communication system, the method comprising:

[0232] Determine the service link types of available NTN cells, and

[0233] If the mobile terminal supports the service link type of the available NTN cell, NTN cell selection (ie, cell measurement) is performed on the available NTN cell.

[0234] 15. A method according to clause 14, wherein the method further comprises determining a remaining coverage time of a serving NTN cell relative to the mobile terminal and performing a cell selection based on available NTN cells if the remaining coverage time does not exceed a threshold.

[0235] 16. A method according to clause 14 or 15, wherein the method further comprises determining a distance between the mobile terminal and a reference point of a serving NTN cell and, if the distance equals or exceeds a threshold, performing a cell selection based on available NTN cells.

[0236] 17. A method as claimed in any of clauses 14 to 16, wherein the serving link type of the available NTN cells is Earth Mobile or Quasi-Earth Fixed.

[0237] 18. A method as claimed in any of clauses 14 to 17, wherein the mobile terminal receives information about the movement of the serving NTN cell and the coverage time is determined based on the information about the movement of the serving NTN cell.

[0238] 19. A method as described in any of clauses 14 to 18, wherein the list of available cells is received from the network.

[0239] 20. A method as described in clause 19, wherein the list of available cells comprises one or more NTN cells based on which the mobile terminal is allowed to perform NTN cell selection, or one or more NTN cells based on which the mobile terminal is not allowed to perform NTN cell selection.

[0240] 21. A method as described in any preceding clause, wherein NTN cell selection (eg, measurement) is based on mobility information (eg, speed, trajectory, altitude, relative speed to satellite) of the mobile terminal.

[0241] 22. A mobile terminal for use in a 5G New Radio (NR) mobile communication system, the mobile terminal being configured to implement the method described in any of the preceding clauses.

[0242] 23. A method for a network entity of a 5G New Radio (NR) mobile communication system, the method comprising:

[0243] Receive NTN capability information from the mobile terminal,

[0244] determining a NTN cell list for the mobile terminal based on the received capability information and service link information of the available NTN cells, and

[0245] Provide the NTN cell list to the mobile terminal.

[0246] 24. A method according to clause 23, wherein the method further comprises receiving mobility information of the mobile terminal from the mobile terminal, and determining the NTN cell list based on the mobility information of the mobile terminal.

[0247] 25. A method as described in any preceding clause, wherein the NTN capability information comprises information on the NTN capabilities of the mobile terminal and / or information on the NTN service link capabilities of the mobile terminal.

[0248] 26. A network entity for use in a 5G New Radio (NR) mobile communication system, the network entity being configured to implement the method of clause 23 or 24.

[0249] 27. A method for performing non-terrestrial network (NTN) cell selection (i.e., measurement) by a mobile terminal in a 5G New Radio (NR) mobile communication system, the method comprising:

[0250] Zero or more available NTN cells are determined for which cell selection is performed based on one or more of the following:

[0251] NTN cell list received from the network,

[0252] Available NTN cell service link types,

[0253] The service link capability of the mobile terminal,

[0254] Coverage time of the serving NTN cell, and

[0255] The distance between the mobile terminal and the reference point of the serving NTN cell.

[0256] 28. A 3GPP mobile communication system configured to implement any one of the preceding clauses.

[0257] 29. A computer-readable storage medium having computer-executable instructions stored thereon, which, when executed by a 3GPP mobile communication system, cause the 3GPP mobile communication system to perform the method as described in any of the preceding clauses.

[0258] Therefore, an embodiment of the present invention provides a method for a user equipment (UE) of a non-terrestrial network (NTN), the method comprising: receiving auxiliary information for cell reselection related to the non-terrestrial network (NTN) from a network; and performing measurements on neighboring cells for cell reselection based on the auxiliary information, wherein the auxiliary information includes ephemeris information about the neighboring cells. In an embodiment, the auxiliary information is included in a system information block (SIB) broadcasted by at least one of a serving cell and a neighboring cell.

[0259] In an embodiment, the UE receives a system information block (SIB) from a network, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0260] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0261] Therefore, an embodiment of the present invention provides a method of a network entity, the method comprising: sending auxiliary information related to a non-terrestrial network (NTN) for cell reselection to a user equipment (UE); wherein the auxiliary information is used to perform measurements on neighboring cells for cell reselection, and wherein the auxiliary information includes ephemeris information about the neighboring cells.

[0262] In an embodiment, the assistance information is included in a system information block (SIB) broadcast by at least one of the serving cell and the neighboring cell.

[0263] In an embodiment, the network entity sends a system information block (SIB) to the UE, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0264] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0265] Therefore, an embodiment of the present invention provides a user equipment (UE) for a non-terrestrial network (NTN), the UE comprising: a transmitter; a receiver; and at least one processor, coupled to the transmitter and the receiver, and configured to: receive auxiliary information for cell reselection related to the non-terrestrial network (NTN) from a network, and perform measurements on neighboring cells for cell reselection based on the auxiliary information, wherein the auxiliary information includes ephemeris information about the neighboring cells.

[0266] In an embodiment, the assistance information is included in a system information block (SIB) broadcast by at least one of the serving cell and the neighboring cell.

[0267] In an embodiment, at least one processor is configured to receive a system information block (SIB) from a network, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0268] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0269] Therefore, an embodiment of the present invention provides a network entity, the network entity comprising: a transmitter; a receiver; and at least one processor, coupled to the transmitter and the receiver, and configured to: send auxiliary information for cell reselection related to a non-terrestrial network (NTN) to a user equipment (UE), wherein the auxiliary information is used to perform measurements on neighboring cells for cell reselection, and wherein the auxiliary information includes ephemeris information about the neighboring cells.

[0270] In an embodiment, the assistance information is included in a system information block (SIB) broadcast by at least one of the serving cell and the neighboring cell.

[0271] In an embodiment, at least one processor is configured to send a system information block (SIB) to a UE, wherein the SIB includes first information of a first type regarding neighbor cells for measurement of the neighbor cells, the first type including an NTN and a terrestrial network (TN).

[0272] In an embodiment, the auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN. In an embodiment, the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

[0273] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method for a user equipment (UE) of a non-terrestrial network (NTN), the method comprising: receiving assistance information for cell reselection related to a non-terrestrial network (NTN) from a network; as well as Perform measurements on neighboring cells based on the assistance information for cell reselection, The auxiliary information includes ephemeris information about neighboring cells.

2. The method according to claim 1, wherein: The assistance information is included in a system information block (SIB) broadcasted by at least one of the serving cell and the neighboring cell.

3. The method according to claim 1, further comprising: Receive a System Information Block (SIB) from the network, The SIB includes first information of a first type on neighboring cells for measuring the neighboring cells, and the first type includes an NTN and a terrestrial network (TN).

4. The method according to claim 3, in, The auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN, and The SIB includes third information about a time for determining when to start measuring the neighboring cell, and fourth information about a location for determining when to start measuring the neighboring cell.

5. A method of a network entity, the method comprising: Sending assistance information related to a non-terrestrial network (NTN) for cell reselection to a user equipment (UE); The auxiliary information is used to perform measurements on neighboring cells for cell reselection, and The auxiliary information includes ephemeris information about neighboring cells.

6. The method according to claim 5, wherein: The assistance information is included in a system information block (SIB) broadcasted by at least one of the serving cell and the neighboring cell.

7. The method according to claim 5, further comprising: Sending a system information block (SIB) to the UE, The SIB includes first information of a first type on neighboring cells for measuring the neighboring cells, and the first type includes an NTN and a terrestrial network (TN).

8. The method according to claim 7, in, The auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN, and The SIB includes third information about a time for determining when to start measuring the neighboring cell, and fourth information about a location for determining when to start measuring the neighboring cell.

9. A user equipment (UE) for a non-terrestrial network (NTN), the UE comprising: Transmitter; Receiver; and At least one processor, coupled to the transmitter and the receiver, and configured to: receiving assistance information for cell reselection related to a non-terrestrial network (NTN) from the network, and Perform measurements on neighboring cells based on the assistance information for cell reselection, The auxiliary information includes ephemeris information about neighboring cells.

10. The UE according to claim 9, wherein: The assistance information is included in a system information block (SIB) broadcasted by at least one of the serving cell and the neighboring cell.

11. The UE according to claim 9, wherein: The at least one processor is further configured to receive a system information block (SIB) from a network, and The SIB includes first information of a first type on neighboring cells for measuring the neighboring cells, and the first type includes an NTN and a terrestrial network (TN).

12. The UE according to claim 11, in, The auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN, and The SIB includes third information about a time for determining when to start measuring the neighboring cell, and fourth information about a location for determining when to start measuring the neighboring cell.

13. A network entity, comprising: Transmitter; Receiver; and At least one processor, coupled to the transmitter and the receiver, and configured to: Sending assistance information related to a non-terrestrial network (NTN) for cell reselection to a user equipment (UE), The auxiliary information is used to perform measurements on neighboring cells for cell reselection, and The auxiliary information includes ephemeris information about neighboring cells.

14. The network entity according to claim 13, wherein: The assistance information is included in a system information block (SIB) broadcasted by at least one of the serving cell and the neighboring cell.

15. The network entity according to claim 13, wherein: The at least one processor is further configured to send a system information block (SIB) to the UE, and The SIB includes first information of a first type about a neighboring cell for measuring the neighboring cell, the first type includes an NTN and a terrestrial network (TN), The auxiliary information includes different information of a second type based on the serving cell, the second type including NTN and TN, and the SIB includes third information about a time for determining when to start measurement of a neighboring cell, and fourth information about a location for determining when to start measurement of a neighboring cell.

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