Method and apparatus for cell measurements in wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a user equipment (UE) in a wireless communication system includes receiving a message including measurement object information; performing a neighbour cell measurement based on the measurement object information; and transmitting a measurement report based on the neighbour cell measurement, The measurement object information includes a first list of configurations, in which each entry includes a cell index, a physical cell identifier (ID), and cell individual offset information, and a second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.

Description

METHOD AND APPARATUS FOR CELL MEASUREMENTS IN WIRELESS COMMUNICATION SYSTEM

[0001] Certain examples of the present disclosure provide one or more techniques for handling cell measurements in a network. For example, certain examples of the present disclosure provide one or more techniques for configuring, and / or reporting capability for, a neighbour cell measurement in a 3rd Generation Partnership Project (3GPP) 4th Generation (4G) and / or 5th Generation (5G) Terrestrial Network (TN) and / or Non Terrestrial Network (NTN).

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

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

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

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

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

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

[0008] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.

[0009] In both NR NTN and IoT NTN systems, the introduction of signaling neighbor satellite assistance information for the purpose of neighbor cell measurements was addressed in Rel-17 for NR NTN and in Rel-18 for IoT NTN. However, despite these advancements, there remain unresolved challenges in IoT NTN, particularly regarding the configuration of neighboring cell measurements. Specifically, there is no clear method for configuring a user equipment (UE) to measure a neighboring cell, including which information fields need to be utilized, how they should be employed, and how a network should indicate the applicable neighbor satellite assistance information.

[0010] In addition, Rel-18 introduced the possibility of signaling neighbor satellite assistance information in a terrestrial network, enabling UEs in idle, inactive, and connected modes to efficiently measure neighboring NTN cells while camping on or connected to a terrestrial cell. Without this enhancement, achieving seamless mobility from terrestrial networks (TN) to non-terrestrial networks (NTN) would present significant challenges. The intended use case involves controlled mobility between TN and NTN, particularly when the UE is in RRC idle or RRC connected modes. This is especially relevant for rural areas with limited or economically unfeasible terrestrial network coverage.

[0011] Nevertheless, enabling such controlled mobility introduces several technical challenges and gaps that remain unresolved. These include how a UE can report the types of NTN cell measurements it supports when camping on or connected to a terrestrial network, how to configure a UE to perform NTN cell measurements while connected to a terrestrial cell, and how the UE can acquire new system information blocks (SIB) from an NTN cell while still connected to a terrestrial network. These issues necessitate the development of new methods and algorithms to ensure seamless mobility and efficient operation in the hybrid TN and NTN environment.

[0012] In an embodiment, a method performed by a user equipment (UE) in a wireless communication system is provided. The method includes receiving a message including measurement object information; performing a neighbour cell measurement based on the measurement object information; and transmitting a measurement report based on the neighbour cell measurement, The measurement object information includes a first list of configurations, in which each entry includes a cell index, a physical cell identifier (ID), and cell individual offset information, and a second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.

[0013] In an embodiment, a method performed by a base station in a wireless communication system is provided. The method includes transmitting a message including measurement object information; and receiving a measurement report for a neighbour cell measurement associated with the measurement object information. The measurement object information includes a first list of configurations, in which each entry includes a cell index, a physical cell ID, and cell individual offset information, and a second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.

[0014] In an embodiment, a UE in a wireless communication system is provided. The UE includes a transceiver and at least one processor. The at least one processor is configured to receive, via the transceiver, a message including measurement object information, perform a neighbour cell measurement based on the measurement object information, and transmit, via the transceiver, a measurement report based on the neighbour cell measurement. The measurement object information includes a first list of configurations, in which each entry includes a cell index, a physical cell ID, and cell individual offset information, and a second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.

[0015] In an embodiment, a base station in a wireless communication system is provided. The base station includes a transceiver and at least one processor. The at least one processor is configured to transmit, via the transceiver, a message including measurement object information and receive, via the transceiver, a measurement report for a neighbour cell measurement associated with the measurement object information. The measurement object information includes a first list of configurations, in which each entry includes a cell index, a physical cell ID, and cell individual offset information, and a second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.

[0016] It is an aim of certain examples of the present disclosure to address, solve and / or mitigate, at least partly, at least one of the problems and / or disadvantages associated with the related art, for example at least one of the problems and / or disadvantages described herein. It is an aim of certain examples of the present disclosure to provide at least one advantage over the related art, for example at least one of the advantages described herein.

[0017] The present invention is defined in the independent claims. Advantageous features are defined in the dependent claims. Embodiments or examples disclosed in the description and / or figures falling outside the scope of the claims are to be understood as examples useful for understanding the present invention.

[0018] Various embodiments of the present disclosure provide techniques that enhance the configuration and execution of measurements for non-terrestrial network (NTN) cells, addressing the technical challenges identified in both NR NTN and IoT NTN contexts. By enabling a user equipment (UE) to report its capabilities for NTN cell measurements, embodiments ensure that the network can effectively configure and manage measurement operations. These techniques apply to scenarios where the UE is connected to an NTN cell as well as when it is connected to a terrestrial cell, ensuring seamless integration and improved performance across hybrid network environments.

[0019] Additionally, embodiments of the present disclosure facilitate the efficient measurement of neighboring NTN cells while the UE is connected to a terrestrial cell. This capability addresses significant challenges associated with mobility between terrestrial networks (TN) and NTNs, particularly in rural or remote areas where terrestrial coverage is limited or economically unfeasible to extend. By providing mechanisms for configuring the UE to measure NTN cells and acquire necessary system information blocks (SIBs) from NTN cells while connected to a terrestrial network, embodiments enable reliable mobility and enhanced connectivity in diverse deployment scenarios.

[0020] Through these advancements, embodiments of the present disclosure improve the scalability, reliability, and efficiency of hybrid TN and NTN operations without limiting the invention to any specific application or purpose, thereby ensuring broad applicability across various network configurations and use cases.

[0021] Other aspects, advantages and salient features of the invention will become apparent to those skilled in the art from the following detailed description taken in conjunction with the accompanying drawings.

[0022] Figure 1 illustrates an exemplary NTN architecture and scenario;

[0023] Figure 2 illustrates an exemplary ephemeris synchronization operation;

[0024] Figure 3 illustrates an exemplary handover procedure;

[0025] Figure 4 illustrates an example of signalling neighbour satellite / cell assistance information in NTN;

[0026] Figure 5 illustrates an example of a terrestrial cell signalling neighbouring satellite assistance information to a UE connected to a terrestrial network;

[0027] Figure 6 illustrates an example of configuring a UE to measure NTN cells in RRC connected;

[0028] Figure 7 illustrates an example of configuring a UE to measurement specific NTN cells and ephemeris using satellite IDs;

[0029] Figure 8 illustrates examples of rules and methods when acquiring SIBxx in a terrestrial network where SIB31 is not broadcasted;

[0030] Figure 9 illustrates an example of signalling capabilities in order to set up NTN measurements in a terrestrial network;

[0031] Figure 10 is a flowchart of an exemplary method, for a UE, for configuring neighbour NTN cell measurements in a network;

[0032] Figure 11 is a flowchart of an exemplary method, for a base station, for configuring neighbour NTN cell measurements in a network; and

[0033] Figure 12 illustrates a block diagram of a base station (BS) according to embodiments of the present disclosure.

[0034] Figure 13 illustrates a user equipment (UE) according to embodiments of the present disclosure.

[0035] The following description of examples of the present disclosure, with reference to the accompanying drawings, is provided to assist in a comprehensive understanding of the present invention, as defined by the claims. The description includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the examples described herein can be made without departing from the scope of the invention.

[0036] The same or similar components may be designated by the same or similar reference numerals, although they may be illustrated in different drawings.

[0037] Detailed descriptions of techniques, structures, functions, operations or processes known in the art may be omitted for clarity and conciseness, and to avoid obscuring the subject matter of the present invention.

[0038] The terms and words used herein are not limited to the bibliographical or standard meanings, but, are merely used to enable a clear and consistent understanding of the invention.

[0039] Throughout the description and claims of this specification, the words "comprise", "include" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other features, elements, components, integers, steps, processes, operations, functions, characteristics, properties and / or groups thereof.

[0040] Throughout the description and claims of this specification, the singular form, for example "a", "an" and "the", encompasses the plural unless the context otherwise requires. For example, reference to "an object" includes reference to one or more of such objects.

[0041] Throughout the description and claims of this specification, language in the general form of "X for Y" (where Y is some action, process, operation, function, activity or step and X is some means for carrying out that action, process, operation, function, activity or step) encompasses means X adapted, configured or arranged specifically, but not necessarily exclusively, to do Y.

[0042] Features, elements, components, integers, steps, processes, operations, functions, characteristics, properties and / or groups thereof described or disclosed in conjunction with a particular aspect, embodiment, example or claim are to be understood to be applicable to any other aspect, embodiment, example or claim described herein unless incompatible therewith.

[0043] The skilled person will appreciate that the techniques described herein may be used in any suitable combination.

[0044] In the present disclosure, the following acronyms / definitions may be used.

[0045] - 3GPP: 3rd Generation Partnership Project

[0046] - 4G: 4th Generation

[0047] - 5G: 5th Generation

[0048] - 5GC: 5G Core

[0049] - 6G: 6th Generation

[0050] - AMF: Access and Mobility Management Function

[0051] - CDMA: Code Division Multiple Access

[0052] - EDGE: Enhanced Data rates for GSM Evolution

[0053] - eMTC: enhanced Machine Type Communications

[0054] - eNB: evolved Node B

[0055] - E-UTRA: Evolved Universal Terrestrial Radio Access

[0056] - E-UTRAN: Evolved Universal Terrestrial Radio Access Network

[0057] - GEO: Geosynchronous Equatorial Orbit

[0058] - GERAN: GSM EDGE Radio Access Network

[0059] - gNB: next generation Node B

[0060] - GSM: Groupe Special Mobile

[0061] - GSO: Geosynchronous Orbit

[0062] - HAPS: High Altitude Platform Station

[0063] - ID: Identity / Identification

[0064] - IE: Information Element

[0065] - IoT: Internet of Things

[0066] - LEO: Lower Earth Orbit

[0067] - LTE: Long Term Evolution

[0068] - LTE-M: Long Term Evolution Machine Type Communication

[0069] - MEO: Medium Earth Orbit

[0070] - MME: Mobile Management Entity

[0071] - MTC: Machine-Type Communications

[0072] - NB: Narrowband

[0073] - NG: Next Generation

[0074] - NG-RAN: Next Generation Radio Access Network

[0075] - NGSO: Non-Geosynchronous Orbit

[0076] - NR: New Radio

[0077] - NTN: Non-Terrestrial Network

[0078] - PVT: Position, Velocity, Time

[0079] - RAN: Radio Access Network

[0080] - RAT: Radio Access Technology

[0081] - Rel: Release

[0082] - RLF: Radio Link Failure

[0083] - RRC: Radio Resource Control

[0084] - RRM: Radio Resource Management

[0085] - SIB: System Information Block

[0086] - TA: Timing Advance

[0087] - TLE: Two-Line Element

[0088] - TN: Terrestrial Network

[0089] - TS: Technical Specification

[0090] - Txxx: Timer xxx

[0091] - UE: User Equipment

[0092] - UL: Uplink

[0093] - WLAN: Wireless Local Area Network

[0094] - X2 / Xn: Interface between RAN nodes

[0095] Overview of NTN

[0096] One of the areas currently under development in 3GPP 5G wireless technology is support for NTNs. An NTN is a network in which one or more nodes (e.g. a Next Generation Radio Access Network (NG-RAN) node) are provided by a non-terrestrial infrastructure, for example a satellite or High Altitude Platform Station (HAPS). Advantages of using an NTN include (i) extending coverage to regions, such as remote areas, with limited or no coverage from more traditional terrestrial networks, (ii) providing continuous coverage in the event of inoperability of traditional terrestrial networks, such as during natural disasters, and (iii) enhancing overall reliability, resilience and capacity when used in conjunction with existing terrestrial networks.

[0097] Figure 1 illustrates an exemplary NTN architecture and scenario.

[0098] A satellite network implementing a network node provides coverage through one or more radio beams forming a "footprint" on the surface of the Earth defining a coverage area or cell. An NTN cell may be Earth-moving (i.e. moving over the Earth's surface according to the motion of the satellite, for example in the case of a Lower Earth Orbit (LEO) satellite), Earth-fixed (i.e. a fixed area of the Earth's surface, for example in the case of a Geosynchronous Equatorial Orbit (GEO) satellite) or quasi-Earth-fixed (i.e. a fixed area of the Earth's surface but is maintained for only a limited time as the satellite passes by).

[0099] Internet of Things (IoT) NTN was a 3GPP study and work item in 3GPP Release 17 to provide NTN access for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) IoT devices (e.g. Narrowband (NB)-IoT and Long Term Evolution Machine Type Communication (LTE-M), including enhanced Machine Type Communication (eMTC)). IoT operation is critical in remote areas with low / no cellular connectivity for many different industries. The capabilities of NB-IoT and eMTC are a good fit for many applications but some applications may require satellite connectivity to provide coverage beyond terrestrial deployments.

[0100] New Radio (NR) NTN was a work item in Release 17 to specify adaptation to allow NR to function over NTN.

[0101] Following the work items in Release 17 there were work items to enhance NR and IoT NTN in Release 18.

[0102] Due to the movement of satellites in a non-stationary orbit (e.g. LEO), the cells that a User Equipment (UE) see will be moving (i.e. Earth-moving cells). This results in frequent UE handover from one cell to another, and this handover of service will happen constantly. In view of this, mobility is one of the key issues in both NR NTN and IoT NTN.

[0103] Overview of NB-IoT and LTE-M

[0104] NB-IoT is a 3GPP-defined network based on 4th Generation (4G) E-UTRAN that supports ultra-low complexity devices with very narrow bandwidth that was introduced in 3GPP Release 13. The use case of NB-IoT is to serve massive IoT application, where requirements for instance are to support enhanced coverage, power-efficient operation and a large number of devices. Some of the features introduced are:

[0105] Support for enhanced coverage through low bandwidth and extreme amounts of repetitions.

[0106] Power efficient operation by allowing the UE to sleep for very long times, relaxed requirements and more efficient signal to establish with a cell.

[0107] LTE-M or eMTC is a 3GPP-defined network that is an extension of 4G E-UTRAN that supports low-complexity devices with more narrow bandwidths compared to normal LTE and further simplifications of procedures. Similar to NB-IoT, the use case is to serve massive IoT, but with more capabilities. Instead of being an entirely new type of device with major air interface changes as in NB-IoT, the LTE-M inherits most feature of a regular LTE device, but with some adaptations for low complexity considerations.

[0108] Overview of NTN System Information

[0109] As NTN has a number of NTN-specific information elements that are only required when accessing an NTN cell, and also due to the relatively large information elements, it was agreed that new System Information Blocks (SIBs) are needed.

[0110] In NR NTN, SIB19 contains the required information to access an NTN cell, as shown in Table 1 below:

[0111] -SIB19SIB19contains satellite assistance information for NTN access.SIB19information element-- ASN1START-- TAG-SIB19-STARTSIB19-r17 ::= SEQUENCE {ntn-Config-r17 NTN-Config-r17 OPTIONAL, -- Need Rt-Service-r17 INTEGER (0..549755813887) OPTIONAL, -- Need RreferenceLocation-r17 ReferenceLocation-r17 OPTIONAL, -- Need RdistanceThresh-r17 INTEGER(0..65525) OPTIONAL, -- Need Rntn-NeighCellConfigList-r17 NTN-NeighCellConfigList-r17 OPTIONAL, -- Need RlateNonCriticalExtension OCTET STRING OPTIONAL,...,[[ntn-NeighCellConfigListExt-v1720 NTN-NeighCellConfigList-r17 OPTIONAL -- Need R]]}NTN-NeighCellConfigList-r17 ::= SEQUENCE (SIZE(1..maxCellNTN-r17)) OF NTN-NeighCellConfig-r17NTN-NeighCellConfig-r17 ::= SEQUENCE {ntn-Config-r17 NTN-Config-r17 OPTIONAL, -- Need RcarrierFreq-r17 ARFCN-ValueNR OPTIONAL, -- Need RphysCellId-r17 PhysCellId OPTIONAL -- Need R}-- TAG-SIB19-STOP-- ASN1STOPSIB19field descriptionsdistanceThreshDistance from the serving cell reference location and is used in location-based measurement initiation in RRC_IDLE and RRC_INACTIVE, as defined in TS 38.304. Each step represents 50m.ntn-ConfigProvides parameters needed for the UE to access NR via NTN access such as Ephemeris data, common TA parameters, k_offset, validity duration for UL sync information and epoch.ntn-NeighCellConfigList, ntn-NeighCellConfigListExtProvides a list of NTN neighbour cells including theirntn-Config, carrier frequency andPhysCellId. This set includes all elements ofntn-NeighCellConfigListand all elements ofntn-NeighCellConfigListExt. Ifntn-Configis absent for an entry inntn-NeighCellConfigListExt, thentn-Configprovided in the entry at the same position inntn-NeighCellConfigListapplies. Network providesntn-Configfor the first entry ofntn-NeighCellConfigList.If thentn-Configis absent for any other entry inntn-NeighCellConfigList, thentn-Configprovided in the previous entry inntn-NeighCellConfigListapplies.referenceLocationReference location of the serving cell provided via NTN quasi-Earth fixed system and is used in location-based measurement initiation in RRC_IDLE and RRC_INACTIVE, as defined in TS 38.304.t-ServiceIndicates the time information on when a cell provided via NTN quasi-Earth fixed system is going to stop serving the area it is currently covering. The field indicates a time in multiples of 10 ms after 00:00:00 on Gregorian calendar date 1 January, 1900 (midnight between Sunday, December 31, 1899 and Monday, January 1, 1900). The exact stop time is between the time indicated by the value of this field minus 1 and the time indicated by the value of this field.

[0112] In IoT NTN, SIB31 contains the required information to access an IoT NTN cell, as shown in Table 2 below:

[0113] - SystemInformationBlockType31The IESystemInformationBlockType31contains satellite assistance information for the serving cell.SystemInformationBlockType31is only signalled in a NTN cell.SystemInformationBlockType31information element-- ASN1STARTSystemInformationBlockType31-r17 ::= SEQUENCE {servingSatelliteInfo-r17 ServingSatelliteInfo-r17,lateNonCriticalExtension OCTET STRING OPTIONAL,...}ServingSatelliteInfo-r17 ::= SEQUENCE {ephemerisInfo-r17 CHOICE {stateVectors EphemerisStateVectors-r17,orbitalParameters EphemerisOrbitalParameters-r17},nta-CommonParameters-17 SEQUENCE {nta-Common-r17 INTEGER (0..8316827) OPTIONAL, -- Need OPnta-CommonDrift-r17 INTEGER (-261935..261935) OPTIONAL, -- Need OPnta-CommonDriftVariation-r17 INTEGER (0..29479) OPTIONAL -- Need OP},ul-SyncValidityDuration-r17 ENUMERATED {s5, s10, s15, s20, s25, s30, s35, s40,s45, s50, s55, s60, s120, s180, s240, s900},epochTime-r17 SEQUENCE {startSFN-r17 INTEGER (0..1023),startSubFrame-r17 INTEGER (0..9)} OPTIONAL, -- Need OPk-Offset-r17 INTEGER (0..1023),k-Mac-r17 INTEGER (1..512) OPTIONAL, -- Need OP...}-- ASN1STOPSystemInformationBlockType31field descriptionsepochTimeEpoch time of the satellite ephemeris data and common TA parameters, see TS 36.213. The reference point for epoch time of the serving satellite ephemeris and Common TA parameters is the uplink time synchronization reference point.epochTimeis the starting time of a DL subframe indicated bystartSFNandstartSubframe. For serving cell, thestartSFNindicates the current SFN or the next upcoming SFN after the frame where the message indicating theepochTimeis received.If the field is absent, the UE uses the starting time of the DL subframe corresponding to the end of the SI window during which the SI message carrying SIB31(-NB) is transmitted.E-UTRAN always includesepochTimewhen SIB31(-NB) is provided through dedicated signalling.In case of handover or conditional handover, this field is based on the timing of the target cell, i.e. thestartSFNandstartSubFramenumber indicated in this field refers to the SFN and sub-frame of the target cell, and UE considers the target cell epoch time (indicated by thestartSFNandstartSubFramein this field) to be the frame nearest to the frame whereRRCConnectionReconfigurationmessage is received.k-MacScheduling offset used when downlink and uplink frame timing are not aligned at the eNB, see TS 36.213. Unit in ms.If the field if absent, the UE uses the (default) value of 0.k-OffsetScheduling offset used in the timing relationships in NTN, see TS 36.213. Unit in ms.nta-CommonNetwork-controlled common TA, see TS 36.213. Unit of μs.Step of 32.55208×10-3μs. Actual value = field value * 32.55208×10-3μs.If the field is absent, the UE uses the (default) value of 0.nta-CommonDriftDrift rate of the common TA, see TS 36.213. Unit of μs / s.Step of 0.2 ×10-3μs / s. Actual value = field value * 0.2 ×10-3.If the field is absent, the UE uses the (default) value of 0.nta-CommonDriftVariationDrift rate variation of the common TA, see TS 36.213. Unit of μs / s2.Step of 0.2 ×10-4μs / s2. Actual value = field value * 0.2 ×10-4.If the field is absent, the UE uses the (default) value of 0.orbitalParametersInstantaneous values of the satellite orbital parameters. The signalled values are only valid for the duration as defined byul-SyncValidityDurationandepochTime.

[0114] The system information contains at least one of the following:

[0115] -Serving cell ephemeris elements. This allows the UE to calculate the satellite position for doppler and time pre-compensation. This information may be provided in two formats:

[0116] *Position, Velocity, Time (PVT) format. This describes a (X,Y,Z) position as well as a speed vector (vX, vY, vZ).

[0117] *Orbital parameters. This describes the orbital movements of the satellite which is then used to infer the satellite position.

[0118] -Timing Advance (TA) common parameters. This provides the common timing advance parameters which is introduced to compensate for the feeder link delays. The signalling comprises the following (in total taking up 57 bits):

[0119] *Absolute TA common (23 bits).

[0120] *Drift of the TA common, defining how the TA common drifts, i.e. the first derivative of the TA common (19 bits).

[0121] *Variation of the TA common, defining how the TA common varies, i.e. the second derivative of the TA common (15 bits).

[0122] -Synchronization validity duration. This is used to define how long the ephemeris and TA common is valid.

[0123] -Epoch time. This defines when the synchronization validity duration should start.

[0124] -K-Offset. This is a scheduling offset for timing relationship in NTN.

[0125] -K-Mac. This is a scheduling offset used when the downlink and uplink frame timing is not aligned.

[0126] - NR NTN specific information also includes (as part of 3GPP TS 38.331):

[0127] *T-Service (signalled in SIB3 in IoT NTN).

[0128] *Reference location and distance threshold. This is used for location-based measurement initiation in RRC IDLE and RRC Connected mode.

[0129] *Neighbour cell ephemeris. This is used for idle mode measurements.

[0130] Overview of NTN System Information Acquisition

[0131] As ephemeris information constantly changes due to the movement of the NTN payload (e.g. satellite), there is a need to make sure that the UE is correctly synchronized. Thus, whenever a UE connects to an eNB, the UE needs to read the system information (e.g. SIB19 or SIB31).

[0132] Figure 2 illustrates an exemplary ephemeris synchronization operation.

[0133] Referring to Figure 2(a) SIB31 functions as normal, and referring to Figure 2(b) UE fails to read SIB31 during T318 which then expires and triggers RLF.

[0134] In IoT NTN, every time SIB31 is read, a timer (T317) associated with the ephemeris element is started. At expiry of T317, the UE is no longer considered synchronized and should re-acquire SIB31 in order to stay synchronized.

[0135] In IoT NTN, since an IoT UE (LTE-M and NB-IoT UE) is not expected to be able to acquire system information in connected mode, the UE tunes away and is likely unreachable while reading SIB31.

[0136] If the IoT NTN UE is unable to read the SIB31 within a timer (T318) with a configured duration, the UE performs Radio Link Failure (RLF) similar to other cases where RLF is performed.

[0137] In NR NTN, the UE may ensure that it has a recent ephemeris (SIB19 in NR) by reading the SIB in time by UE implementation.

[0138] The T317 timer is different compared to a normal timer in Radio Resource Control (RRC) as it is not started at having received the SIB31. This is because the ephemeris has an epoch time, which is the reference point in time of when the ephemeris is defined. Thus the T317 is started from the epoch time, which may be in the past or in the future relative to have received SIB31. This means that in an UE implementation, the timer may be started with a different value with what was signalled according to what was signalled in the field ul-SyncValidityDuration in SIB31.

[0139] Overview of IoT NTN neighbour cell ephemeris SIB

[0140] In Release 18 WI enhancements on IoT NTN, it was agreed to introduce neighbour cell ephemeris. The agreed SIB is defined as shown in Table 3 below.

[0141] -SystemInformationBlockTypeXXThe IESystemInformationBlockTypeXXcontains satellite assistance information for neighbour cells.SystemInformationBlockTypeXXinformation element-- ASN1STARTSystemInformationBlockTypeXX-r18 ::= SEQUENCE {neighSatelliteInfoList-r18 NeighSatelliteInfoList-r18 OPTIONAL, -- Need ORneighValidityDuration-r18 ENUMERATED {s5, s10, s15, s20, s25, s30, s35, s40,s45, s50, s55, s60, s120, s180, s240, s900} OPTIONAL, -- Need OPlateNonCriticalExtension OCTET STRING OPTIONAL,...}NeighSatelliteInfoList-r18 ::= SEQUENCE (SIZE(1..maxSat-r18)) OF NeighSatelliteInfo-r18NeighSatelliteInfo-r18 ::= SEQUENCE {satelliteId-r18 SatelliteId-r18,ephemerisInfo-r18 CHOICE {stateVectors EphemerisStateVectors-r17,orbitalParameters EphemerisOrbitalParameters-r17},nta-CommonParameters-18 SEQUENCE {nta-Common-r18 INTEGER (0..8316827) OPTIONAL, -- Need OPnta-CommonDrift-r18 INTEGER (-261935..261935) OPTIONAL, -- Need OPnta-CommonDriftVariation-r18 INTEGER (0..29479) OPTIONAL -- Need OP},epochTime-r18 SEQUENCE {startSFN-r18 INTEGER (0..1023),startSubFrame-r18 INTEGER (0..9)} OPTIONAL, -- Need OPk-Mac-r18 INTEGER (1..512) OPTIONAL, -- Need OPt-ServiceStartNeigh-r18 TimeOffsetUTC-r17 OPTIONAL, -- Need OR...}-- ASN1STOPSystemInformationBlockTypeXXfield descriptionsepochTimeEpoch time of the neighbour satellite ephemeris data and common TA parameters, see TS 36.213. The reference point for epoch time of the neighbour satellite ephemeris and Common TA parameters is the uplink time synchronization reference point.epochTimeis the starting time of a DL subframe indicated bystartSFNandstartSubframe. If this field is absent, the UE uses epoch time of the serving cell, otherwise the field is based on the timing of the serving cell, i.e. the SFN and sub-frame number indicated in this field refers to the SFN and sub-frame of the serving cell. ThestartSFNindicates the SFN nearest to the frame where the message indicating theepochTimeis received.k-MacScheduling offset used when downlink and uplink frame timing are not aligned at the eNB, see TS 36.213. Unit in ms.If the field if absent, the UE uses the (default) value of 0.k-OffsetScheduling offset used in the timing relationships in NTN, see TS 36.213. Unit in ms.neighValidityDurationValidity duration of the neighbour satellite ephemeris data and common TA parameters, i.e. maximum time duration (fromepochTime) during which the UE can apply the satellite ephemeris without acquiring new satellite ephemeris, see TS 36.213. Unit in second.Values5corresponds to 5 seconds, values10corresponds to 10 seconds and so on.If this field is absent,the UE uses validity duration from the serving cell assistance information.nta-CommonNetwork-controlled common TA, see TS 36.213. Unit of μs.Step of 32.55208 ×10-3μs. Actual value = field value * 32.55208 ×10-3.If the field is absent, the UE uses the (default) value of 0.nta-CommonDriftDrift rate of the common TA, see TS 36.213. Unit of μs / s.Step of 0.2 ×10-3μs / s. Actual value = field value * 0.2 ×10-3.If the field is absent, the UE uses the (default) value of 0.nta-CommonDriftVariationDrift rate variation of the common TA, see TS 36.213. Unit of μs / s2.Step of 0.2 ×10-4μs / s2. Actual value = field value * 0.2 ×10-4.If the field is absent, the UE uses the (default) value of 0.t-ServiceStartNeighIndicates the earliest time when the area covered by the current serving cell is going to be covered by the neighbour cell(s) served by the satellite indicated bysatelliteId. This field is only present for the neighbour cell(s) provided via NTN quasi-Earth fixed system.

[0142] Each element of the field neighSatelliteInfoList, the neighSatelliteInfo, is referred to as a neighbour satellite assistance info element.

[0143] In order to associate a broadcasted neighbour satellite assistance information with a cell or a frequency, as signalled in SIB3 or SIB5, a satellite Identity (ID) is introduced. Thus for each frequency in SIB5, the network can signal a list of satellite IDs that correspond to neighbour satellite assistance elements in SIBxx. Thus when the UE attempts to detect cells on a frequency in idle mode, the UE will use the ephemeris to try to detect cells at a specific timing and frequency offsets. Thus if there are two satellite IDs signalled in for a frequency, when the UE attempts to detect cells, it will search two different timing and frequency offsets corresponding to the satellite positions as derived by the ephemeris. The UE may also attempt to detect other cells.

[0144] The field neighValidityDuration is the validity duration of all of the neighbour satellite ephemeris data and the common TA parameters of all of the neighbour satellite assistance elements. This can be used by the UE to determine roughly when to re-acquire the SIBxx both in RRC idle and RRC connected. When (re-)acquiring the SIBxx, in RRC connected, the UE may use the already existing timer T318 to acquire the SIBxx. The T318 is already used to acquire the SIB31 according to Release 17 specifications. There are also some specifications and special considerations for this purpose:

[0145] If the UE acquires SIBxx during T318, the T318 does not stop when SIB31 is acquired.

[0146] The T318 is stopped when both SIB31 and SIBxx are acquired.

[0147] When the T318 expires, RLF is only performed when SIB31 has not been acquired.

[0148] Overview of NTN Ephemeris Formats

[0149] There are three ways of signalling the ephemeris in NTN:

[0150] 1. PVT format,

[0151] 2. Orbital ephemeris elements, and

[0152] 3. TLE ephemeris elements (only used for Discontinuous Coverage in IoT NTN).

[0153] PVT format signals XYZ position along with the speed vector vXYZ as shown in information elements of Table 4 below.

[0154] - EphemerisStateVectorsThe IEEphemerisStateVectorsprovides satellite ephemeris in format of position and velocity state vectors in ECEF.EphemerisStateVectorsinformation element-- ASN1STARTEphemerisStateVectors-r17 ::= SEQUENCE {positionX-r17 PositionStateVector-r17,positionY-r17 PositionStateVector-r17,positionZ-r17 PositionStateVector-r17,velocityVX-r17 VelocityStateVector-r17,velocityVY-r17 VelocityStateVector-r17,velocityVZ-r17 VelocityStateVector-r17}PositionStateVector-r17 ::= INTEGER (-33554432..33554431)VelocityStateVector-r17 ::= INTEGER (-131072..131071)-- ASN1STOPEphemerisStateVectorsfield descriptionspositionX, positionY, positionZX, Y, Z coordinate of satellite position state vector in ECEF. Unit in meter.Step of 1.3 m. Actual value = field value * 1.3.velocityVX, velocityVY, velocityVZX, Y, Z coordinate of satellite velocity state vector in ECEF. Unit in meter / second.Step of 0.06 m / s. Actual value = field value * 0.06.

[0155] The position elements (X, Y, Z respectively) each occupy 26 bits and the speed elements (vX, vY, vZ) each occupy 18 bits. Altogether they occupy 132 bits.

[0156] Orbital Ephemeris Format

[0157] The ephemeris orbital parameters (also referred to as Keplerian format) provide parameters that indicate how a celestial body moves in space, which allows for accurate synchronization and prediction of future NTN payload position.

[0158] Ephemeris orbital elements are signalled by the following elements (164 bits total):

[0159] - SemiMajorAxis (33 bits)

[0160] - Eccentricity (20 bits)

[0161] - Periapsis (28 bits)

[0162] - Longitude (28 bits)

[0163] - Inclination (27 bits)

[0164] - Anomaly (28 bits)

[0165] TLE Orbital Parameters

[0166] The Two-Line Element (TLE) parameters are based on TLE set, which is industry-acknowledged data format for signalling the movement of a celestial body. Whereas the PVT and orbital ephemeris formats may be used to perform accurate synchronization, TLE parameters may be used primarily for long term prediction. For example, the TLE parameters allow for accurate satellite-pass prediction of up to several days in the future.

[0167] A full set of TLE parameters can occupy more than 50 Bytes of data containing many fields not required in 3GPP. Therefore, a reduced set of TLE parameters may be used instead, for example based on the following (totalling 189 bits):

[0168] - Inclination (21 bits)

[0169] - Argument of perigee (22 bits)

[0170] - Right ascension of the ascending node (22 bits)

[0171] - Mean anomaly (22 bits)

[0172] - Eccentricity (24 bits)

[0173] - Mean Motion (34 bits)

[0174] - B* signalled by (i) a decimal (18 bits), and (ii) an exponent (5 bits)

[0175] - Epoch star (21 bits)

[0176] Overview of E-UTRAN and eMTC connected mode mobility

[0177] E-UTRAN connected mode mobility functions similar to other cellular standards and connected mode mobility is also supported for E-UTRAN eMTC. A standard connected mode handover is performed only when triggered by the eNB.

[0178] Figure 3 illustrates an exemplary handover procedure.

[0179] In step 301, a UE is configured with measurement configuration via RRCConnectionReconfiguration.

[0180] In step 302, the UE performs neighbour cell measurements, which are configured by the network.

[0181] In step 303a, the UE identifies that a measurement report (of a neighbour cell) is triggered. In step 303b, the UE transmits the measurement report (MeasurementReport) to a (Source) eNB.

[0182] The (Source) eNB performs handover decision based on the measurement report received from the UE. In step 304, an inter-node procedures are performed, whereby the Source eNB sends a Handover Request to Target eNB after having decided whether to trigger a handover and the Target eNB send a Handover Request Acknowledge to Source eNB.

[0183] In step 305, the (Source) eNB triggers a handover command which is sent to UE. This handover command comprises the RRC message RRCConnectionReconfiguration, containing the mobilityControlInfo field.

[0184] In step 306, UE prepares for handover and performs a handover via the random access procedure.

[0185] A measurement configuration comprises a set of measurement objects and measurement reporting configuration for RRM purposes. These measurement objects define the configurations of the measurements that a UE may perform in RRC connected. A measurement object is related to an either a frequency or a RAT. There is, for instance, inter-RAT E-UTRA measurement object (MeasObjectEUTRA), which may configure intra or inter-frequency measurements. The MeasObjectEUTRA contains configurations, such as the carrier frequency, measurement bandwidth, neighbour cell configurations, specific cells to measure, cells not to measure and report and many more configurations. There are also Inter-RAT measurement object that contains all of the necessary configurations to perform connected mode measurements of NR (MeasObjectNR), UTRA (MeasObjectUTRA), GERAN (MeasObjectGERAN), CDMA2000 (MeasObjectCDMA2000), or WLAN (MeasObjectWLAN).

[0186] The measurement reporting configuration contains rules that define when a measurement report containing measurements may be sent. These are typically defined by measurement reporting triggering conditions (also called measurement events), thresholds, and configuring what measure may be reported.

[0187] Certain examples of the present disclosure provide one or more techniques for handling cell measurements in a network. For example, certain examples of the present disclosure provide one or more techniques for configuring, and / or reporting capability for, a neighbour cell measurement in a 3GPP 4G and / or 5G TN and / or NTN. However, the skilled person will appreciate that the present invention is not limited to these examples, and may be applied in any suitable system or standard, for example one or more existing and / or future generation wireless communication systems or standards, including any existing or future releases of the same standards specification, for example 3GPP 5G, 5G-advanced or 6th Generation (6G).

[0188] The functionality of the various network entities and other features disclosed herein may be applied to corresponding or equivalent entities or features in the same or any other suitable communication systems or standards. Corresponding or equivalent entities or features may be regarded as entities or features that perform the same or similar role, function or purpose within the network.

[0189] For example, the functionality of a base station or the like (e.g. eNB, gNB, NB, RAN node, access point, wireless point, transmission / reception point, central unit, distributed unit, radio unit, remote radio head, etc.) in the examples below may be applied to any other suitable type of entity performing RAN functions, and the functionality of a UE or the like (e.g. electronic device, user device, mobile station, subscriber station, customer premises equipment, terminal, remote terminal, wireless terminal, vehicle terminal, etc.) in the examples below may be applied to any other suitable type of device.

[0190] A particular network entity may be implemented as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, and / or as a virtualised function instantiated on an appropriate platform, e.g. on a cloud infrastructure.

[0191] The skilled person will appreciate that the present invention is not limited to the specific examples disclosed herein. For example:

[0192] - The techniques disclosed herein are not limited to 3GPP 4G and / or 5G.

[0193] - One or more entities in the examples disclosed herein may be replaced with one or more alternative entities performing equivalent or corresponding functions, processes or operations.

[0194] - One or more of the messages in the examples disclosed herein may be replaced with one or more alternative messages, signals or other type of information carriers that communicate equivalent or corresponding information.

[0195] - One or more further elements or entities may be added to the examples disclosed herein.

[0196] - One or more non-essential elements or entities may be omitted in certain examples.

[0197] - The functions, processes or operations of a particular entity in one example may be divided between two or more separate entities in an alternative example.

[0198] - The functions, processes or operations of two or more separate entities in one example may be performed by a single entity in an alternative example.

[0199] - Information carried by a particular message in one example may be carried by two or more separate messages in an alternative example.

[0200] - Information carried by two or more separate messages in one example may be carried by a single message in an alternative example.

[0201] - The order in which operations are performed and / or the order in which messages are transmitted may be modified, if possible, in alternative examples.

[0202] Certain examples of the present disclosure may be provided in the form of an apparatus / device / network entity configured to perform one or more defined network functions and / or a method therefor. Certain examples of the present disclosure may be provided in the form of a system (e.g. network or wireless communication system) comprising one or more such apparatuses / devices / network entities, and / or a method therefor.

[0203] Certain examples of the present disclosure provide a UE and / or a base station (e.g. eNB, gNB) configured to perform a method according to any example, aspect, embodiment and / or claim disclosed herein.

[0204] Certain examples of the present disclosure provide a network (or wireless communication system) comprising a UE, base station (e.g. eNB, gNB, etc.), and / or any other suitable network entity / entities according to any examples, aspects, embodiments and / or claims disclosed herein.

[0205] Certain examples of the present disclosure provide a computer program comprising instructions which, when the program is executed by a computer or processor, cause the computer or processor to carry out a method according to any example, aspect, embodiment and / or claim disclosed herein.

[0206] Certain examples of the present disclosure provide a computer or processor-readable data carrier having stored thereon a computer program according to any example, aspect, embodiment and / or claim disclosed herein.

[0207] Various examples of the present disclosure will now be described in more detail.

[0208] Figure 4 illustrates an example of signalling neighbour satellite / cell assistance information in NTN.

[0209] Both in NR NTN and IoT NTN, the possibility to signal neighbour satellite assistance information for the purpose of neighbour cell measurements have been introduced. This was introduced in Rel-17 for NR NTN and Rel-18 for IoT NTN.

[0210] However, for IoT NTN, there are still some missing aspects related to how to configure a neighbouring cell measurement, for example:

[0211] - How is a UE configured to measure a neighbouring cell?

[0212] - What information fields need to be used, and how should they be used?

[0213] - How does a network indicate what neighbour satellite assistance information to use?

[0214] - Are there any special measurement considerations for NTN?

[0215] Furthermore, in Rel-18 the possibility to signal the above introduced neighbour satellite assistance in a terrestrial network was also introduced.

[0216] Figure 5 illustrates an example of a terrestrial cell signalling neighbouring satellite assistance information to a UE connected to a terrestrial network.

[0217] The purpose of this is to allow for UEs in idle, inactive and connected mode to efficiently measure neighbouring NTN cells while the UE is camping or is connected to a terrestrial cell. Without introducing this enhancement, the mobility from TN to NTN may be very challenging.

[0218] The use case of introducing this enhancement is that controlled mobility from a terrestrial network and a non-terrestrial network may occur, either when the UE is RRC idle or RRC connected. This is useful for instance when the UE is located in a rural region with poor coverage, for instance in areas where it is not economically feasible to extend terrestrial coverage to.

[0219] However, in order for this to work, there are still several challenges and missing methods and algorithms that are addressed by various examples of the present disclosure:

[0220] - A UE reporting what type of NTN cell measurement it supports when camping or connected to a terrestrial network

[0221] - How to configure a UE to measure an NTN cell when connected to a terrestrial cell?

[0222] - How to acquire the new SIB when in connected to a terrestrial network?

[0223] Certain examples of the present disclosure provide one or more techniques for reporting capabilities and / or configuring connected mode measurements of NTN cells, both when the UE is connected to an NTN cell, and when it is connected to a terrestrial cell.

[0224] Certain examples of the present disclosure provide a method, for a UE, for configuring neighbour NTN cell measurements in a network, the method comprising: receiving, from a base station, a message comprising configuration for the UE to perform one or more neighbour NTN cell measurements; performing one or more neighbour NTN cell measurements according to the configuration; and transmitting, to the base station, a measurement report based on the measurements, wherein the configuration comprises a measurement object defining configurations of measurements that a UE may perform, and wherein the measurement object comprises one or more satellite IDs for associating a neighbour cell or frequency to neighbour cell satellite assistance information.

[0225] Certain examples of the present disclosure provide a method, for a base station, for configuring neighbour NTN cell measurements in a network, the method comprising: transmitting, to a UE, a message comprising configuration for the UE to perform one or more neighbour NTN cell measurements; and receiving, from the UE, a measurement report based on one or more neighbour NTN cell measurements performed by the UE according to the configuration, wherein the configuration comprises a measurement object defining configurations of measurements that the UE may perform, and wherein the measurement object comprises one or more satellite IDs for associating a neighbour cell or frequency to neighbour cell satellite assistance information.

[0226] In certain examples, the method for the UE may further comprise: if a handover request indicating an NTN cell is received from the base station, performing handover to the NTN cell.

[0227] In certain examples, the method for the base station may further comprise: determining whether to trigger handover of the UE to an NTN cell based on the measurement report.

[0228] In certain examples, the UE may be in connected mode.

[0229] In certain examples, the UE may be a NB-IoT UE or an eMTC UE.

[0230] In certain examples, the measurement object (e.g. MeasObjectEUTRA) may specify information applicable for intra-frequency or inter-frequency E-UTRA cells.

[0231] In certain examples, the message may be an RRCConnectionReconfiguration message.

[0232] In certain examples, the one or more satellite IDs may comprise a satellite ID per cell.

[0233] In certain examples, the measurement object may further comprise one or more IDs (e.g. cellsToAddModList) indicating cells the UE may attempt to measure.

[0234] In certain examples, the satellite assistance information may comprise ephemeris.

[0235] In certain examples, the neighbour cell satellite assistance information may be signalled in a certain SIB (e.g. SIB33).

[0236] In certain examples, the base station may be associated with an NTN cell or a TN cell.

[0237] In various examples, the ephemeris is not only applicable for satellite payloads, but can also apply to other platforms such a HAPS. Accordingly, references herein to "satellite ephemeris" may apply not only to satellites, but also to other NTN platforms and / or payloads.

[0238] In the present disclosure, "New SIB", "SIBxx" and similar, refer to the System Information Block that is being introduced for IoT NTN that contains neighbour satellite assistance information such as ephemeris, for the purpose of neighbour cell measurements. In future specifications the name of this SIB may for instance be SystemInformationBlockType33, SystemInformationBlockType34, or any other suitable naming. As the techniques disclosed herein also apply to NB-IoT, any references to any types of SIB may also encompass the NB-IoT version(s), which may end with "-NB" (SystemInformationBlockType31 -> SystemInformationBlockType31-NB). Thus SIBxx may include SIB33(-NB) or SIB34(-NB).

[0239] While "terrestrial network" is used in the present disclosure, the skilled person will appreciate that the techniques disclosed herein may be applied, not only to a terrestrial network, but also any suitable type of network that is not an NTN network, for example an Air-To-Ground network or similar. Therefore, references to TN or TN cell may include references to a non-NTN or non-NTN cell.

[0240] In the present disclosure, the wording "RRC connected", "connected mode" and "RRC_CONNECTED" may be used interchangably. Similarly, "idle mode", "RRC idle" and "RRC_IDLE" may be used interchangeably. In certain examples, when "idle mode" is mentioned, this may also encompass "inactive mode", "RRC inactive" and / or "RRC_INACTIVE", as the actions performed in these states in general are the same or similar.

[0241] In the present disclosure, references to "monitoring" may include the idle / inactive mode action of detecting and measuring a cell on a frequency, while "measuring" may include the action of detecting and measuring in connected mode. In certain examples the terms may be used interchangeably.

[0242] Various examples of the present disclosure are described in terms of LTE IoT. However, the skilled person will appreciate that the various techniques described herein may also be applied more widely, for example to NG-RAN nodes, such as gNBs, NG-eNBs (eNBs connected via 5GC), and all related, newly defined and / or existing RRC signaling and / or messages, X2, Xn, S1, NG, and / or F1 signalling and / or messages, and / or related network entities (e.g. MME, AMF, other). For instance, references to a measurement object may include references to a measurement object for E-UTRAN or for NR, i.e. MeasObjectEUTRA or MeasObjectNR.

[0243] The skilled person will appreciate that the various techniques disclosed herein may also be applied to NR NTN.

[0244] Configuring NTN neighbour cell measurements

[0245] Figure 6 illustrates an example of configuring a UE to measure NTN cells in RRC connected.

[0246] In step 601, a base station (eNB or gNB) may broadcast a new SIB containing neighbour cell assistance information. A UE may receive the new SIB. In step 602, the base station may configure the UE in RRC connected with measObject to measure NTN cells. In step 603, the UE may detect and measure NTN cells based on the measObject. In step 604a, the UE may identify that the measurement report is triggered. In step 604b, if the measurement report is triggered, the UE may report NTN cells in a Measurement Report to the base station.

[0247] Figure 7 illustrates an example of configuring a UE to measurement specific NTN cells and ephemeris using satellite IDs.

[0248] In step 701, a base station (eNB or gNB) may broadcast a new SIB containing neighbour cell assistance information. A UE may receive the new SIB. In step 702, the base station may configure the UE in RRC connected with measObject to measure specific cells with satelliteId(s). In step 703, the UE may detect and measure (only) cells indicated in the measObject, using the satelliteId(s). In step 704a, the UE may identify that the measurement report is triggered. In step 704b, if the measurement report is triggered, the UE may report NTN cells in a Measurement Report to the base station.

[0249] For configuring NTN neighbour cell measurements, there are some enhancements required that are different from configuring terrestrial neighbour cell measurements in a terrestrial network. This is mostly related to the fact that the ephemeris and neighbour cell assistance information is required to measure an NTN cell efficiently, which is signalled in a new SIB. For each neighbour satellite assistance element in new SIB, there is a satellite identifier that identifies the neighbour satellite assistance information, i.e. the ephemeris. This is also signalled for specific frequencies in SIB3 / SIB5, making it possible to tie a inter / intra-frequency to a neighbour satellite, making it possible to know how to track a specific frequency. This is also signalled in SIB31, because there may be the case that there are multiple cells at different frequencies that originate from the same satellite as the serving cell. These issues are relevant in an NTN cell as well in a terrestrial cell when configuring to measure an NTN cell.

[0250] In certain examples of the present disclosure, the satellite ID (satelliteId in SystemInformationBlockType31 or SystemInformationBlockTypeXX) in SIB31 is always present if the new SIB is signalled. This can be expressed as "satelliteId is always present if SystemInformationBlockTypeXX is signalled". If the SIBxx is dedicatedly signalled, then the network ensures that the satellite ID is delivered to the UE. Similarly, the satellite ID in SIB31 is always signalled if there are satellite ID(s) signalled in SIB3 and SIB5.

[0251] In order to measure neighbour satellite in connected mode, there similarly needs to be a satellite ID configured in Measurement Objects (MeasObject), which is the configuration where connected mode measurements are configured.

[0252] To allow for a UE to measure a neighbouring NTN cell in connected mode, there may need to be considerations on how the satellite ID(s) are signalled.

[0253] In certain examples of the present disclosure, since a measurement objects indicates that the UE may measure a frequency along with a set of cells, a set of satellite IDs, per cell may be signalled. This is configured as a list of satellite IDs, which is a parallel list with the current cellsToAddModList which includes currently includes the cellIndex, physCellId and cellIndividualOffset. As it is a parallel list, the length of the list of satellite IDs would have to have the same length as that of the list of cells. If a satellite ID is not configured for a specific cell, the UE assumes that the cell is a terrestrial cell. An example of the measurement configuration for this technique can be seen in Table 5 below.

[0254] -MeasObjectEUTRAThe IEMeasObjectEUTRAspecifies information applicable for intra-frequency or inter-frequency E-UTRA cells.MeasObjectEUTRAinformation element-- ASN1STARTMeasObjectEUTRA ::= SEQUENCE {carrierFreq ARFCN-ValueEUTRA,allowedMeasBandwidth AllowedMeasBandwidth,presenceAntennaPort1 PresenceAntennaPort1,neighCellConfig NeighCellConfig,offsetFreq Q-OffsetRange DEFAULT dB0,-- Cell listcellsToRemoveList CellIndexList OPTIONAL, -- Need ONcellsToAddModList CellsToAddModList OPTIONAL, -- Need ON-- Excluded listexcludedCellsToRemoveList CellIndexList OPTIONAL, -- Need ONexcludedCellsToAddModList ExcludedCellsToAddModList OPTIONAL, -- Need ONcellForWhichToReportCGI PhysCellId OPTIONAL, -- Need ON...,[[measCycleSCell-r10 MeasCycleSCell-r10 OPTIONAL, -- Need ONmeasSubframePatternConfigNeigh-r10 MeasSubframePatternConfigNeigh-r10 OPTIONAL -- Need ON]],[[widebandRSRQ-Meas-r11 BOOLEAN OPTIONAL -- Cond WB-RSRQ]],[[ altTTT-CellsToRemoveList-r12 CellIndexList OPTIONAL, -- Need ONaltTTT-CellsToAddModList-r12 AltTTT-CellsToAddModList-r12 OPTIONAL, -- Need ONt312-r12 CHOICE {release NULL,setup ENUMERATED {ms0, ms50, ms100, ms200,ms300, ms400, ms500, ms1000}} OPTIONAL, -- Need ONreducedMeasPerformance-r12 BOOLEAN OPTIONAL, -- Need ONmeasDS-Config-r12 MeasDS-Config-r12 OPTIONAL -- Need ON]],[[allowedCellsToRemoveList-r13 CellIndexList OPTIONAL, -- Need ONallowedCellsToAddModList-r13 AllowedCellsToAddModList-r13 OPTIONAL, -- Need ONrmtc-Config-r13 RMTC-Config-r13 OPTIONAL, -- Need ONcarrierFreq-r13 ARFCN-ValueEUTRA-v9e0 OPTIONAL -- Need ON]],[[tx-ResourcePoolToRemoveList-r14 Tx-ResourcePoolMeasList-r14 OPTIONAL, -- Need ONtx-ResourcePoolToAddList-r14 Tx-ResourcePoolMeasList-r14 OPTIONAL, -- Need ONfembms-MixedCarrier-r14 BOOLEAN OPTIONAL -- Need ON]],[[measSensing-Config-r15 MeasSensing-Config-r15 OPTIONAL -- Need ON]],[[measRSS-DedicatedConfig-r16 SetupRelease {MeasRSS-DedicatedConfig-r16} OPTIONAL -- Need ON]],[[cellsToAddModList-v8xy CellsToAddModList-v18xy OPTIONAL -- Need ON]]}MeasObjectEUTRA-v9e0 ::= SEQUENCE {carrierFreq-v9e0 ARFCN-ValueEUTRA-v9e0}MeasRSS-DedicatedConfig-r16 ::= SEQUENCE {rss-ConfigCarrierInfo-r16 RSS-ConfigCarrierInfo-r16 OPTIONAL, -- Need OPcellsToAddModList-v1610 CellsToAddModList-v1610 OPTIONAL -- Need ON}CellsToAddModList ::= SEQUENCE (SIZE (1..maxCellMeas)) OF CellsToAddModCellsToAddModList-v1610 ::= SEQUENCE (SIZE (1..maxCellMeas)) OF CellsToAddMod-v1610CellsToAddModList-v18xy ::= SEQUENCE (SIZE (1..maxCellMeas)) OF CellsToAddMod-v18xyCellsToAddMod ::= SEQUENCE {cellIndex INTEGER (1..maxCellMeas),physCellId PhysCellId,cellIndividualOffset Q-OffsetRange}CellsToAddMod-v1610 ::= SEQUENCE {rss-MeasPowerBias-r16 RSS-MeasPowerBias-r16}CellsToAddMod-v18xy ::= SEQUENCE {satelliteId-r18 SatelliteId-r18 OPTIONAL -- Need ON}. . . OMITTED . . .-- ASN1STOPMeasObjectEUTRAfield descriptionsallowedCellsToAddModListList of cells to add / modify in the list of allow-listed cells.allowedCellsToRemoveListList of cells to remove from the list of allow-listed cells.altTTT-CellsToAddModListList of cells to add / modify in the cell list for which the alternative time to trigger specified byalternativeTimeToTriggerinreportConfigEUTRA, if configured, applies.altTTT-CellsToRemoveListList of cells to remove from the list of cells for alternative time to trigger.carrierFreqIdentifies E-UTRA carrier frequency for which this configuration is valid. E-UTRAN does not configure more than one measurement object for the same physical frequency regardless of the E-ARFCN used to indicate this. CarrierFreq-r13 is included only when the extension list measObjectToAddModListExt-r13 is used. IfcarrierFreq-r13is present,carrierFreq(i.e., without suffix) may be set to valuemaxEARFCN.cellIndexEntry index in the cell list. An entry may concern a range of cells, in which case this value applies to the entire range.cellIndividualOffsetCell individual offset applicable to a specific cell. Value dB-24 corresponds to -24 dB, dB-22 corresponds to -22 dB and so on.cellsToAddModListList of cells to add / modify in the cell list.cellsToAddModList-v1610indicates list of RSS assistance information which is used for the correspondingphysCellId. If E-UTRAN includescellsToAddModList-v1610orcellsToAddModList-v18xy, it includes the same number of entries, and listed in the same order, as incellsToAddModList(i.e. without suffix).. . . OMITTED . . .satelliteIdThe satellite ID used to associate a cell to a neighbour satellite assistance information as signalled inSystemInformationBlockTypeXX. If the field is not present for a cell andSystemInformationBlockTypeXXis signalled, the UE considers the cell to be a terrestrial cell.. . . OMITTED . . .

[0255] Alternatively or additionally, if there is no satellite IDs signalled for a frequency at all, the UE interprets this as if the frequency of a measurement object is a terrestrial network. Similarly, if there are one or more satellite IDs signalled for a frequency, the UE may interpret this as the frequency only being an NTN frequency.

[0256] In certain examples of the present disclosure, the MeasObject only indicates a single satellite ID per measurement object. Similarly, if the network does not configure a satellite ID in the measurement object, the UE assumes that the cell or the measurement object is for a terrestrial cell. This may also need to include the condition that whether SIBxx is configured, which would be mean that the full condition would be that if SIBxx is broadcasted and no satellite ID is configured for the measurement object.

[0257] Similarly, for inter-RAT measurements connected mode measurements, such as measuring NR NTN cells, the satellite ID may be configured as part of the NR measurement object, i.e. MeasObjectNR. An example of the measurement configuration can be seen in Table 6 below.

[0258] -MeasObjectNRThe IEMeasObjectNRspecifies information applicable for inter-RAT NR neighbouring cells.MeasObjectNRinformation element-- ASN1STARTMeasObjectNR-r15 ::= SEQUENCE {carrierFreq-r15 ARFCN-ValueNR-r15,rs-ConfigSSB-r15 RS-ConfigSSB-NR-r15,threshRS-Index-r15 ThresholdListNR-r15 OPTIONAL, -- Need ORmaxRS-IndexCellQual-r15 MaxRS-IndexCellQualNR-r15 OPTIONAL, -- Need ORoffsetFreq-r15 Q-OffsetRangeInterRAT DEFAULT 0,excludedCellsToRemoveList-r15 CellIndexList OPTIONAL, -- Need ONexcludedCellsToAddModList-r15 CellsToAddModListNR-r15 OPTIONAL, -- Need ONquantityConfigSet-r15 INTEGER (1.. maxQuantSetsNR-r15),cellsForWhichToReportSFTD-r15 SEQUENCE (SIZE (1..maxCellSFTD)) OF PhysCellIdNR-r15 OPTIONAL, -- Need OR...,[[ cellForWhichToReportCGI-r15 PhysCellIdNR-r15 OPTIONAL, -- Need ONderiveSSB-IndexFromCell-r15 BOOLEAN OPTIONAL, -- Need ONss-RSSI-Measurement-r15 SS-RSSI-Measurement-r15 OPTIONAL, -- Need ONbandNR-r15 CHOICE {release NULL,setup FreqBandIndicatorNR-r15} OPTIONAL -- Need ON]],[[rmtc-ConfigNR-r16 SetupRelease {RMTC-ConfigNR-r16} OPTIONAL -- Cond SharedSpectrum]],[[cellsToRemoveList-r16 CellIndexList OPTIONAL, -- Need ONcellsToAddModList-r16 CellsToAddModListNR-r16 OPTIONAL -- Need ON]],[[cellsToAddModList-r18 CellsToAddModListNR-r18 OPTIONAL -- Need ON]]}RS-ConfigSSB-NR-r15 ::= SEQUENCE {measTimingConfig-r15 MTC-SSB-NR-r15,subcarrierSpacingSSB-r15 ENUMERATED {kHz15, kHz30, kHz120, kHz240},...,[[ ssb-ToMeasure-r15 CHOICE {release NULL,setup SSB-ToMeasure-r15} OPTIONAL -- Need ON]],[[ssb-PositionQCL-CommonNR-r16 SSB-PositionQCL-RelationNR-r16 OPTIONAL, -- Cond SharedSpectrum2ssb-PositionQCL-CellsToAddModListNR-r16 SSB-PositionQCL-CellsToAddModListNR-r16 OPTIONAL, -- Cond SharedSpectrumssb-PositionQCL-CellsToRemoveListNR-r16 SEQUENCE (SIZE (1..maxCellMeas)) OF PhysCellIdNR-r15 OPTIONAL -- Cond SharedSpectrum]],[[subcarrierSpacingSSB-r17 ENUMERATED {kHz480, kHz960} OPTIONAL, -- Need ORssb-PositionQCL-CommonNR-r17 SSB-PositionQCL-RelationNR-r17 OPTIONAL, -- Cond SharedSpectrum2ssb-PositionQCL-CellsToAddModListNR-r17 SSB-PositionQCL-CellsToAddModListNR-r17 OPTIONAL, -- Cond SharedSpectrumssb-PositionQCL-CellsToRemoveListNR-r17 SEQUENCE (SIZE (1..maxCellMeas)) OF PhysCellIdNR-r15 OPTIONAL -- Cond SharedSpectrum]]}CellsToAddModListNR-r15 ::= SEQUENCE (SIZE (1..maxCellMeas)) OF CellsToAddModNR-r15CellsToAddModListNR-r16 ::= SEQUENCE (SIZE (1..maxCellMeas)) OF CellsToAddModNR-r16CellsToAddModListNR-r18 ::= SEQUENCE (SIZE (1..maxCellMeas)) OF CellsToAddModNR-r18CellsToAddModNR-r15 ::= SEQUENCE {cellIndex-r15 INTEGER (1..maxCellMeas),physCellId-r15 PhysCellIdNR-r15}CellsToAddModNR-r16 ::= SEQUENCE {cellIndex-r16 INTEGER (1..maxCellMeas),physCellId-r16 PhysCellIdNR-r15,cellIndividualOffset-r16 Q-OffsetRange}CellsToAddModNR-v18xy ::= SEQUENCE {satelliteId-r18 SatelliteId-r18 OPTIONAL -- Need ON}. . . OMITTED . . .-- ASN1STOPMeasObjectNRfield descriptionsbandNRIndicates the frequency band of the NR carrier frequency configured in thisMeasObjectNR. This field is always set to setup when the network configures measurements with thisMeasObjectNR.carrierFreqIdentifies the SSB frequency to be measured. E-UTRAN does not configure more than one measurement object for the same SSB frequency.cellIndividualOffsetCell individual offset applicable to a specific cell.deriveSSB-IndexFromCellThe field indicates whether the UE may use, to derive the SSB index of a cell on the indicated SSB frequency and subcarrier spacing, the timing of the NR serving cell with the same SSB frequency and subcarrier spacing if configured. Otherwise, the field indicates whether the UE may use the timing of any detected cell with the same SSB frequency and subcarrier spacing.measDurationNRNumber of consecutive symbols for which the Physical Layer reports samples of RSSI (see TS 38.215). Valuesym1corresponds to one symbol,sym14or12corresponds to 14symbolsof the reference numerology for NCP and 12 symbols for ECP, and so on. IfmeasDurationNR-r17is present, the UE may ignoremeasDurationNR-r16.quantityConfigSetIndicates the n-th element ofquantityConfigNRListprovided inMeasConfig.refSCS-CP-NRIndicates a reference subcarrier spacing and cyclic prefix to be used for RSSI measurements (see TS 38.215).rmtc-FrequencyNRIndicates the center frequency of the measured bandwidth (see TS 38.215).rmtc-PeriodicityNRIndicates the RSSI measurement timing configuration (RMTC) periodicity (see TS 38.215). Valuems40corresponds to 40 ms periodicity,ms80corresponds to 80 ms periodicity, and so on.rmtc-SubframeOffsetNRIndicates the RSSI measurement timing configuration (RMTC) subframe offset (see TS 38.215). If not configured, the UE chooses a random value asrmtc-SubframeOffsetNRformeasDurationNRwhich may be selected to be between 0 and the configuredrmtc-PeriodicityNRwith equal probability.rs-ConfigSSBIndicates the SSB configuration for measuring the set of SS blocks within the SMTC measurement duration.satelliteIdThe satellite ID used to associate a cell to a neighbour satellite assistance information as signalled inSystemInformationBlockTypeXX. If the field is not present for a cell andSystemInformationBlockTypeXXis signalled, the UE considers the cell to be a terrestrial cell.ssb-PositionQCL-NRIndicates the QCL relationship between SS / PBCH blocks for a specific neighbor cell as specified in TS 38.213, clause 4.1. If provided, the cell specific value overwrites the common value signalled byssb-PositionQCL-CommonNRinMeasObjectNRfor the indicated cell.ssb-PositionQCL-CommonNRIndicates the QCL relationship between SS / PBCH blocks for NR neighbor cells as specified in TS 38.213, clause 4.1. Ifssb-PositionQCL-CommonNR-r17is present, the UE may ignoressb-PositionQCL-CommonNR-r16.subcarrierSpacingSSBSubcarrier spacing of SSB.Only the following values are applicable depending on the used frequency:FR1: 15 or 30 kHzFR2-1: 120 or 240 kHzFR2-2: 120, 480, or 960 kHzrmtc-BandwidthNRIndicates the bandwidth for the RSSI measurement.threshRS-IndexList of thresholds for consolidation of L1 measurements per RS index.Conditional presenceExplanationSharedSpectrumThe field is optional Need ON if NR operates with shared spectrum channel access; otherwise, it is not present.SharedSpectrum2The field is mandatory present if NR operates with shared spectrum channel access; otherwise, it is not present.

[0259] In certain examples of the present disclosure, when a UE is configured to measure NTN cell(s), the UE only attempts to acquire the cells that are indicated by the measurement object, i.e. through cellsToAddModList and allowedCellsToAddModList. This is important as the UE may not be able to attempt to detect other cells, as the different timing and frequency offset may make this very challenging. Thus the UE may not detect and measure other cells than what are signalled. The condition for this can for instance be that "if the UE is configured to measure an NTN cell, the UE only measures on the cells explicitly indicated by the measObject for the frequency", or "if a satelliteId is configured for the measObject, the UE only measures on the cells indicated by the measObject for the frequency". An example of UE operation can be defined as shown in Table 7 below.

[0260] IntroductionThe measurement procedures distinguish the following types of cells:1. The serving cell(s) - these are the PCell and one or more SCells, if configured for a UE supporting CA or DC. Likewise, NR serving cell(s) are the NR PCell, NR PSCell and NR SCells, if the UE is configured with MR-DC.2. Listed cells - these are cells listed within the measurement object(s) or, for inter-RAT WLAN, the WLANs matching the WLAN identifiers configured in the measurement object or the WLAN the UE is connected to.3. Detected cells - these are cells that are not listed within the measurement object(s) but are detected by the UE on the carrier frequency(ies) indicated by the measurement object(s) or, for inter-RAT WLAN, the WLANs not included in themeasObjectWLANbut meeting the triggering requirements.NOTE X: For measurement objects measuring NTN cells, the UE only performs measurements on the listed cells indicated by the measurement object.For E-UTRA, the UE measures and reports on the serving cell(s), listed cells, detected cells, transmission resource pools for V2X sidelink communication, and, for RSSI and channel occupancy measurements, the UE measures and reports on any reception on the indicated frequency. For inter-RAT NR, the UE measures and reports on detected cells and, if configured with MR-DC, on NR serving cell(s) and, for RSSI and channel occupancy measurements, the UE measures and reports on the indicated frequency. For inter-RAT UTRA, the UE measures and reports on listed cells and optionally on cells that are within a range for which reporting is allowed by E-UTRAN. For inter-RAT GERAN, the UE measures and reports on detected cells. For inter-RAT CDMA2000, the UE measures and reports on listed cells. For inter-RAT WLAN, the UE measures and reports on listed cells.NOTE 2: For inter-RAT UTRA and CDMA2000, the UE measures and reports also on detected cells for the purpose of SON.NOTE 3: This specification is based on the assumption that typically CSG cells of home deployment type are not indicated within the neighbour list. Furthermore, the assumption is that for non-home deployments, the physical cell identity is unique within the area of a large macro cell (i.e. as for UTRAN).Whenever the procedural specification, other than contained in clause 5.5.2, refers to a field it concerns a field included in theVarMeasConfigunless explicitly stated otherwise i.e. only the measurement configuration procedure covers the direct UE action related to the receivedmeasConfig.Performing measurementsThe UE may:. . . OMITTED . . .**2> else:***3> if a measurement gap configuration is setup; or***3> if the UE does not require measurement gaps to perform the concerned measurements:****4> ifs-Measureis not configured; or****4> if the UE is not in NE-DC and the PCell RSRP, after layer 3 filtering, is lower thans-Measure; or****4> if the UE is in NE-DC and the PSCell RSRP, after layer 3 filtering, is lower thans-Measure; or****4> if the associatedmeasObjectconcerns NR; or****4> ifmeasDS-Configis configured in the associatedmeasObject:*****5> if the UE supports CSI-RS based discovery signals measurement; and*****5> if theeventIdin the associatedreportConfigis set toeventC1oreventC2, or ifreportStrongestCSI-RSsis set totruein the associatedreportConfig:******6> perform the corresponding measurements of CSI-RS resources on the frequency indicated in the concernedmeasObject, applying the discovery signals measurement timing configuration in accordance withmeasDS-Configin the concernedmeasObject;******6> ifreportCRS-Measis set totruein the associatedreportConfig,perform the corresponding measurements of neighbouring cells on the frequencies indicated in the concernedmeasObjectas follows:*******7> for neighbouring cells on the primary frequency, apply the time domain measurement resource restriction in accordance withmeasSubframePatternConfigNeigh,if configured in the concernedmeasObject;*******7> apply the discovery signals measurement timing configuration in accordance withmeasDS-Configin the concernedmeasObject;*****5> else:******6> perform the corresponding measurements of neighbouring cells on the frequencies and RATs indicated in the concernedmeasObjectas follows:*******7> for neighbouring cells on the primary frequency, apply the time domain measurement resource restriction in accordance withmeasSubframePatternConfigNeigh,if configured in the concernedmeasObject;*******7> if the UE supports CRS based discovery signals measurement, apply the discovery signals measurement timing configuration in accordance withmeasDS-Config, if configured in the concernedmeasObject;*******7> for measObject configured with satelliteId, the UE only measures on the cells indicated incellsToAddModListfor the frequency;

[0261] In certain examples of the present disclosure, it is explicitly configured that the UE only needs to attempt to detect the cells as specified in the measurement object. This can be an optional flag measureOnlyIndicatedCells. This also means that only the cells that have been indicated are reported in a measurement report.

[0262] One restriction on configuring neighbour cell measurements needed in an NTN cell would be how many different neighbouring cell ephemeris that are needed to be tracked. This for instance would put a limitation to how many different satelliteIds that can be a part of a measurement object. For instance, if a UE is asked to measure 4 cells in connected mode, the restriction may be that only 2 different types of different satellite IDs may be signalled. This may or may not include the serving cell ephemeris. This may be important as tracking a lot of different satellites with different frequency and timing offsets is difficult for a UE and is independent on the number of cells that are tracked.

[0263] Configuring NTN measurements in a terrestrial network

[0264] Configuring a UE in a terrestrial network to measure an NTN cell may similarly follow the above techniques. However, for configuring measurements of NTN cells, there may need to be some restrictions.

[0265] One such restriction may for instance be that a network is not allowed to configure an NTN cell as part of a conditional handover configuration for a UE connected to a terrestrial cell, i.e. an NTN cell is not configured as part of CondReconfig. An example of UE operation can be defined as shown in Table 8 below.

[0266] Conditional reconfigurationThe network configures the UE with conditional reconfiguration (i.e. conditional handover, conditional PSCell addition, or inter-SN conditional PSCell change) including per candidate target cell anRRCConnectionReconfigurationto be stored and to be applied upon the fulfilment of an associated execution condition.The network may ensure to not configure a UE in a terrestrial network with an NTN cell as a candidate cell as part of conditional reconfiguration.The UE may:*1> if the receivedconditionalReconfigurationincludes thecondReconfigurationToRemoveList:**2> perform the conditional reconfiguration removal procedure as specified in 5.3.5.9.2;*1> if the receivedconditionalReconfigurationincludes thecondReconfigurationToAddModList:**2> perform the conditional reconfiguration addition / modification procedure as specified in 5.3.5.9.3;

[0267] The new SIB can be both broadcasted in a non-terrestrial network as well as a terrestrial network. As the new SIB was originally introduced to broadcast neighbour satellite assistance information in a non-terrestrial network, there needs to be some considerations when signalling it in a terrestrial network.

[0268] One signalled field in theneighValidityDuration, which is the duration in which neighbour satellite assistance information is considered valid. If it is not present, then the UE may use theul-SyncValidityDurationsignalled in SIB31. However, as the SIB31 is not signalled in a terrestrial network, if the field is not present, then there is the issue that UE would not know which value to apply. Thus in certain examples of the present disclosure, when the new SIB is broadcasted in a terrestrial network, the neighbouring validity duration (neighValidityDuration) is always signalled, thus always present. An example of the SIB can be seen in Table 9 below.

[0269] - SystemInformationBlockTypeXXThe IESystemInformationBlockTypeXXcontains satellite assistance information for neighbour cells.SystemInformationBlockTypeXXinformation element-- ASN1STARTSystemInformationBlockTypeXX-r18 ::= SEQUENCE {neighSatelliteInfoList-r18 NeighSatelliteInfoList-r18 OPTIONAL, -- Need ORneighValidityDuration-r18 ENUMERATED {s5, s10, s15, s20, s25, s30, s35, s40,s45, s50, s55, s60, s120, s180, s240, s900} OPTIONAL, -- Need OPlateNonCriticalExtension OCTET STRING OPTIONAL,...}NeighSatelliteInfoList-r18 ::= SEQUENCE (SIZE(1..maxSat-r18)) OF NeighSatelliteInfo-r18NeighSatelliteInfo-r18 ::= SEQUENCE {satelliteId-r18 SatelliteId-r18,ephemerisInfo-r18 CHOICE {stateVectors EphemerisStateVectors-r17,orbitalParameters EphemerisOrbitalParameters-r17},nta-CommonParameters-18 SEQUENCE {nta-Common-r18 INTEGER (0..8316827) OPTIONAL, -- Need OPnta-CommonDrift-r18 INTEGER (-261935..261935) OPTIONAL, -- Need OPnta-CommonDriftVariation-r18 INTEGER (0..29479) OPTIONAL -- Need OP},epochTime-r18 SEQUENCE {startSFN-r18 INTEGER (0..1023),startSubFrame-r18 INTEGER (0..9)} OPTIONAL, -- Need OPk-Mac-r18 INTEGER (1..512) OPTIONAL, -- Need OPt-ServiceStartNeigh-r18 TimeOffsetUTC-r17 OPTIONAL, -- Need OR...}-- ASN1STOPSystemInformationBlockTypeXXfield descriptionsepochTimeEpoch time of the neighbour satellite ephemeris data and common TA parameters, see TS 36.213. The reference point for epoch time of the neighbour satellite ephemeris and Common TA parameters is the uplink time synchronization reference point.epochTimeis the starting time of a DL subframe indicated bystartSFNandstartSubframe. If this field is absent, the UE uses epoch time of the serving cell, otherwise the field is based on the timing of the serving cell, i.e. the SFN and sub-frame number indicated in this field refers to the SFN and sub-frame of the serving cell. ThestartSFNindicates the SFN nearest to the frame where the message indicating theepochTimeis received.k-MacScheduling offset used when downlink and uplink frame timing are not aligned at the eNB, see TS 36.213. Unit in ms.If the field if absent, the UE uses the (default) value of 0.k-OffsetScheduling offset used in the timing relationships in NTN, see TS 36.213. Unit in ms.neighValidityDurationValidity duration of the neighbour satellite ephemeris data and common TA parameters, i.e. maximum time duration (fromepochTime) during which the UE can apply the satellite ephemeris without acquiring new satellite ephemeris, see TS 36.213. Unit in second.Values5corresponds to 5 seconds, values10corresponds to 10 seconds and so on.If this field is absent,the UE uses validity duration from the serving cell assistance information. When broadcasted in a non-NTN cell, the field is always present.nta-CommonNetwork-controlled common TA, see TS 36.213. Unit of μs.Step of 32.55208 ×10-3μs. Actual value = field value * 32.55208 ×10-3.If the field is absent, the UE uses the (default) value of 0.nta-CommonDriftDrift rate of the common TA, see TS 36.213. Unit of μs / s.Step of 0.2 ×10-3μs / s. Actual value = field value * 0.2 ×10-3.If the field is absent, the UE uses the (default) value of 0.nta-CommonDriftVariationDrift rate variation of the common TA, see TS 36.213. Unit of μs / s2.Step of 0.2 ×10-4μs / s2. Actual value = field value * 0.2 ×10-4.If the field is absent, the UE uses the (default) value of 0.t-ServiceStartNeighIndicates the earliest time when the area covered by the current serving cell is going to be covered by the neighbour cell(s) served by the satellite indicated bysatelliteId. This field is only present for the neighbour cell(s) provided via NTN quasi-Earth fixed system.

[0270] In certain examples (e.g. alternative examples), the neighbouring validity duration, if not signalled, is set to a fixed value. This value can for instance be 1 minute, or 1 hour. This allows for very fixed and clear requirements on how often the new SIB may be acquired.

[0271] Acquiring new SIB in connected mode in a terrestrial network

[0272] Figure 8 illustrates examples of rules and methods when acquiring SIBxx in a terrestrial network where SIB31 is not broadcasted.

[0273] When a UE is configured to measure a non-terrestrial network in connected mode, the UE may also be required to regularly acquire the new SIB. In a non-terrestrial network, the UE may acquire the SIB in connected mode during the timer T318. The T318 timer is started when timer T317 expires, and the T317 timer is started according to acquiring SIB31. However, SIB31 is important to broadcast the serving cell satellite assistance information, which is not needed as the cell is now a terrestrial network. Thus the issue is how to acquire the new SIB in this case.

[0274] In certain examples of the present disclosure, the UE starts the timer T317 when successfully acquiring SIBxx in terrestrial network. This would be the action upon reception of SystemInformationBlockTypeXX in a terrestrial network. The value of T317 would use neighValidityDuration instead of the ul-SyncValidityDuration in SIB31, which is not broadcasted.

[0275] In certain examples of the present disclosure, another timer, a new T3xx is started when acquiring the new SIB in a terrestrial network and T318 is started as usual.

[0276] In certain examples of the present disclosure, the UE does not attempt to acquire SIB31 while T318 is running while in a terrestrial network. In other words, the UE acquires the SIB31 only in a non-terrestrial network. An alternative description is that the acquires SIB31, if SIB31 broadcasted.

[0277] In certain examples of the present disclosure, the UE does not declare RLF if T318 has expired and the neither SIB31 or new SIB has been acquired in terrestrial network. It can also be that when T318 expires in a terrestrial network, the UE does not perform RLF. This can be expressed as T318 only expiring if the UE is in a non-terrestrial network, and if the T318 expires in a terrestrial network, the UE only stops attempting to acquire SIBxx.

[0278] In certain examples of the present disclosure, the uplink synchronization is not lost during T318 if T318 runs in a terrestrial network. This would be expressed as the uplink synchronisation is only lost when T318 expires in a non-terrestrial network.

[0279] In certain examples of the present disclosure, the UE stops the timer T318 when only SIBxx has been acquired, and not SIB31. This can alternatively be described as timer T318 being stopped when both SIB31, if broadcasted, and SIBxx has been acquired.

[0280] Examples of the above behaviour can be seen in Table 10 below.

[0281] Actions upon reception ofSystemInformationBlockTypeXXUpon receiving SystemInformationBlockTypeXX (SystemInformationBlockTypeXX-NB) in a cell where SystemInformationBlockType31 is not broadcast:The UE may start or restart timer T317 with the durationneighValidityDuration.T317 expiryThe UE may:*1> if in RRC_CONNECTED and not performing GNSS measurement:**2> in an NTN, inform lower layers that the UL synchronisation is lost;**2> start timer T318;**2> acquireSystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT), if broadcasted, as specified in 5.2.2;**2> if the UE acquiresSystemInformationBlockTypeXX(SystemInformationBlockTypeXX-NBin NB-IoT) as specified in 5.2.2:***3> inform lower layers when UL synchronisation is restored upon successful acquisition ofSystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT);***3> stop timer T318 when bothSystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT), if broadcasted, andSystemInformationBlockTypeXX(SystemInformationBlockTypeXX-NBin NB-IoT) are acquired;**2> else:***3> upon successful acquisition of SystemInformationBlockType31 (SystemInformationBlockType31-NB in NB-IoT):****4> stop timer T318;****4> inform lower layers when UL synchronisation is restored.NOTE 1:SystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT) may be broadcast on a different narrowband or different NB-IoT carrier than the one configured to the UE.NOTE 2: The exact time when UL synchronisation is restored (afterSystemInformationBlockType31orSystemInformationBlockType31-NBin NB-IoT is acquired) is left to UE implementation, which can be from the subframe indicated byepochTimeand optionally before the subframe indicated byepochTime.NOTE 3: For UEs not capable of performing system information acquisition and GNSS measurement at the same time, if the UE cannot complete acquisition ofSystemInformationBlockType31(SystemInformationBlockType31-NB) before the start of GNSS measurement gap, acquisition ofSystemInformationBlockType31(SystemInformationBlockType31-NB) may be postponed until GNSS measurement is completed, and T318 is restarted after GNSS measurement is completed.Detection of radio link failureThe UE may:*1> in case any DAPS bearer is configured, only the target PCell is considered in the following;*1> upon T310 expiry; or*1> upon T312 expiry; or*1> in an NTN upon T318 expiry andSystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT) not acquired; or*1> upon reachingt-Serviceift-Serviceis broadcast; or*1> upon random access problem indication from MCG MAC while neither T300, T301, T304 nor T311 is running; or*1> upon indication from MCG RLC, which is allowed to be send on PCell, that the maximum number of retransmissions has been reached for an SRB or DRB:

[0282] In addition, the conditions for starting and stopping the timer T317 and T318, and the UE operation at expiry of the timer T317 and T318 are shown in Table 11 below.

[0283] TimerStartStopAt expiryT317NOTE1Start or restart from the subframe indicated byepochTimeupon reception ofSystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT), or upon reception ofRRCConnectionReconfigurationmessage for the target cell includingmobilityControlInfo, or upon conditional reconfiguration execution i.e. when applying a storedRRCConnectionReconfigurationmessage for the target cell includingmobilityControlInfo, or when acquiringSystemInformationBlockTypeXXwhenSystemInformationBlockType31is not broadcasted.Stop T317, if it is running, for the source cell upon reception ofRRCConnectionReconfigurationmessage includingmobilityControlInfo, or upon conditional reconfiguration execution i.e. when applying a storedRRCConnectionReconfigurationmessage includingmobilityControlInfo.Perform the actions as specified in 5.3.18 of TS 38.331.T318NOTE1Upon starting acquisition ofSystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT) or upon starting acquisition ofSystemInformationBlockTypeXXin RRC_CONNECTEDUpon successful acquisition ofSystemInformationBlockType31(SystemInformationBlockType31-NBin NB-IoT) if broadcast andSystemInformationBlockTypeXX(SystemInformationBlockTypeXX-NBin NB-IoT) if broadcast, in RRC_CONNECTEDIf security is not activated and the UE is not a NB-IoT UE that supports RRC connection re-establishment for the Control Plane CIoT EPS optimisation: go to RRC_IDLE else: initiate the connection re-establishment procedure.

[0284] In certain examples, the above behaviour, which is very different from how a UE would operate and acquire the system information, may have as a number of conditions one or more of:

[0285] -Operating in a terrestrial network

[0286] *Alternative descriptions could be "if UE is connected to an NTN cell"

[0287] -Operating in a network that broadcasts new SIB but not SIB31

[0288] *For instance "if systemInformationBlockType31(-NB) is not broadcasted"

[0289] -If SIB31 is not broadcasted

[0290] -Configured via a flag acquireTN-SIBxx which indicates the above behaviour, otherwise the UE does for instance not acquire SIBxx in RRC connected.

[0291] UE capabilities related to monitoring NTN from TN

[0292] As disclosed above, the UE may monitor the NTN from a terrestrial network.

[0293] Figure 9 illustrates an example of signalling capabilities in order to set up NTN measurements in a terrestrial network.

[0294] In step 901, a UE may signal UE capability to measure NTN cells in a terrestrial network to a base station (TN eNB / gNB). In step 902, the base station may configure the UE to measure NTN cells. In step 903, the UE may detect and measure NTN cells (i.e., NTN eNB / gNB) based on the configuration for measuring NTN cells. In step 904a, the UE may identify that the measurement report is triggered. In step 904b, if the measurement report is triggered, the UE may report NTN cells in a Measurement Report to the base station.

[0295] In order for the network to be aware of this capability, the capability of monitoring or measuring the NTN cells from a TN cell can be signalled to the network. These type of capabilities may not be a IoT NTN-related capability, as it would be signalled in an terrestrial network. As part of this capability, the UE would be capable of tracking time and frequency offsets. This capability may be apply both for an NR UE, i.e. to measure a NR NTN cell from NR TN cell or an IoT NTN UE, i.e. measuring an IoT NTN (E-UTRAN) cell from a TN E-UTRAN cell.

[0296] Similarly, if a UE is capable of measuring NR NTN cells while in a E-UTRAN terrestrial network, this may also be signalled by the UE.

[0297] There may also need to be detailed information on what the UE is capable of monitoring.

[0298] Whether the UE is capable of monitoring Geosynchronous Orbit (GSO) or Non-Geosynchronous Orbit (NGSO). This could be needed as the requirements on tracking the satellite and the timing and frequency offset are different depending on whether the satellite is stationary or non-stationary. The GSO satellite position is generally quite stable, whereas the NGSO is either moving slowly or extremely quickly. The distinction could for instance be made that the UE is capable of monitoring GEO, Medium Earth Orbit (MEO) or LEO. A UE could for instance only be capable of monitoring GEO-stationary satellites, as the LEO satellites move too fast requiring more advanced signal processing to compensate for the doppler frequency offset caused by the fast movement. There can thus be capabilities for each GSO or NGSO, or for GEO, MEO and LEO.

[0299] In NR NTN and IoT NTN there is already a capability ntn-SupportScenario that specifies which scenario that a UE supports measuring GSO or NGSO. In certain examples of the present disclosure this capability, along with the capability indicating UE supports monitoring or measuring NTN cell from TN cell, indicates that the UE supports monitoring or measuring an NTN cell of a specific type, i.e. GSO and NGSO.

[0300] The UE may also signal whether the UE is capable to monitor NTN cells from idle mode or connected mode. This may be important as the increased complexity of monitoring NTN may only be feasible in one of the modes, i.e. only in idle / inactive mode, but not in connected mode. Similarly, there may be a capability indicating whether a UE can monitor intra- or inter-NTN frequencies. As an extension for UEs connecting to eNB via 5GC, the UE may also signal whether it can monitor NTN cells in RRC inactive. The signalling can for instance be one capability for connected mode, and one capability for both idle and inactive mode.

[0301] Examples of these capabilities can be seen in Table 12 below.

[0302] ntn-Measurements-r18This field indicates whether a UE supports being configured to perform measurements of NTN cells while connected to a non-NTN cell. Measuring an NTN cell includes the capability of the UE to track and compensate for time and frequency offset using the neighbour cell assistance information. This also includes the capability to acquire SystemInformationBlockTypeXX.ntn-NR-Measurements-r18This field indicates whether a UE supports being configured to perform inter-RAT measurements of NR NTN cells while connected to a non-NTN cell. Measuring an NR NTN cell includes the capability of the UE to track and compensate for time and frequency offset using the neighbour cell assistance information. This also includes the capability to acquire SystemInformationBlockTypeXX.ntn-MeasurementsGSO-r18This field indicates whether a UE supports being configured to perform measurements of GSO NTN cells while connected to a non-NTN cell. Measuring an NTN cell includes the capability of the UE to track and compensate for time and frequency offset using the neighbour cell assistance information. This also includes the capability to acquire SystemInformationBlockTypeXX. A UE supporting this feature may also set thentn-ScenarioSupportaccordingly.ntn-MeasurementsNGSO-r18This field indicates whether a UE supports being configured to perform measurements of NGSO NTN cells while connected to a non-NTN cell. Measuring an NTN cell includes the capability of the UE to track and compensate for time and frequency offset using the neighbour cell assistance information. This also includes the capability to acquire SystemInformationBlockTypeXX. A UE supporting this feature may also set thentn-ScenarioSupportaccordingly.

[0303] As an example of how to combine the above techniques, a UE may for instance indicate whether it is capable of one or more of:

[0304] -Monitoring an IoT NTN NGSO cell from an E-UTRAN TN cell in idle or inactive mode

[0305] -Monitoring an IoT NTN GSO cell from an E-UTRAN TN cell in idle or inactive mode

[0306] -Measuring an IoT NTN NGSO cell from an E-UTRAN TN cell in connected mode

[0307] -Measuring an IoT NTN GSO cell from an E-UTRAN TN cell in connected mode

[0308] -Monitoring an NR NTN NGSO cell from an E-UTRAN TN cell in idle or inactive mode

[0309] -Monitoring an NR NTN GSO cell from an E-UTRAN TN cell in idle or inactive mode

[0310] -Measuring an NR NTN NGSO cell from an E-UTRAN TN cell in connected mode

[0311] -Measuring an NR NTN GSO cell from an E-UTRAN TN cell in connected mode

[0312] -Monitoring an NR NTN NGSO cell from an NR TN cell in idle and inactive mode

[0313] -Monitoring an NR NTN GSO cell from an NR TN cell in idle and inactive mode

[0314] -Measuring an NR NTN NGSO cell from an NR TN cell in connected mode

[0315] -Measuring an NR NTN GSO cell from an NR TN cell in connected mode

[0316] There may also be capabilities indicating whether a UE can monitor and evaluate an NTN cell from a terrestrial network in a Conditional Handover Configuration. This is due to the increased complexity related to monitoring for NTN.

[0317] The UE may also indicate whether it is capable of simultaneously monitoring a terrestrial network cell and an NTN cell, or whether measurement gaps are required.

[0318] The UE may also indicate how many NTN cells or satellites that a UE can measure when in a terrestrial network. This can for instance be coupled with how many NTN cells it can measure while measure other terrestrial cells. As an example of how this can be defined, if a UE normally may measure up to 8 terrestrial neighbouring cells, then when configured to measure both terrestrial and NTN neighbouring cells, the number of terrestrial cells can be 4 and NTN cells can be 2, i.e. one NTN cells counts as 2 terrestrial cells. This is due to the extra power consumption likely required for a non-terrestrial cell.

[0319] The UE may also indicate whether it is capable of acquiring SIB33 in connected mode during T318. For a non-IoT device i.e. an E-UTRAN LTE device, this capability may be not be signalled as the UE is in general capable of acquiring SIB in RRC Connected.

[0320] Figure 10 is a flowchart of an exemplary method, for a UE, for configuring neighbour NTN cell measurements in a network.

[0321] Referring to Figure 10, in a first operation 1001, the UE receives, from a base station, a message comprising configuration for the UE to perform one or more neighbour NTN cell measurements. The configuration comprises a measurement object defining configurations of measurements that a UE may perform. The measurement object comprises one or more satellite IDs for associating a neighbour cell or frequency to neighbour cell satellite assistance information.

[0322] In a second operation 1002, the UE performs one or more neighbour NTN cell measurements according to the configuration.

[0323] In a third operation 1003, the UE Transmit, to the base station, a measurement report based on the measurements.

[0324] Figure 11 is a flowchart of an exemplary method, for a base station, for configuring neighbour NTN cell measurements in a network.

[0325] Referring to Figure 11, in a first operation 1101, the base station transmits, to a UE, a message comprising configuration for the UE to perform one or more neighbour NTN cell measurements. The configuration comprises a measurement object defining configurations of measurements that a UE may perform. The measurement object comprises one or more satellite IDs for associating a neighbour cell or frequency to neighbour cell satellite assistance information.

[0326] In a second operation 1102, the base station receives, from the UE, a measurement report based on one or more neighbour NTN cell measurements performed by the UE according to the configuration.

[0327] Figure 12 illustrates a block diagram of a base station (BS) according to embodiments of the present disclosure.

[0328] Referring to the Figure 12, the BS 1200 may include a processor (or controller) 1210, a transceiver 1220 and a memory 1230. However, all of the illustrated components are not essential. The BS 1200 may be implemented by more or less components than those illustrated in Figure 12. In addition, the processor 1210 and the transceiver 1220 and the memory 1230 may be implemented as a single chip according to another embodiment.

[0329] The aforementioned components will now be described in detail.

[0330] The processor 1210 may include one or more processors or other processing devices that control the proposed function, process, and / or method. The operations described in Figures 1 to 11 of the BS 1200 may be implemented by the processor 1210.

[0331] The transceiver 1220 may include a RF transmitter for up-converting and amplifying a transmitted signal, and a RF receiver for down-converting a frequency of a received signal. However, according to another embodiment, the transceiver 1220 may be implemented by more or less components than those illustrated in components.

[0332] The transceiver 1200 may be connected to the processor 1210 and transmit and / or receive a signal. The signal may include control information and data. In addition, the transceiver 1220 may receive the signal through a wireless channel and output the signal to the processor 1210. The transceiver 1220 may transmit a signal output from the processor 1210 through the wireless channel.

[0333] The memory 1230 may store the control information or the data included in a signal obtained by the BS 1200. The memory 1230 may be connected to the processor 1210 and store at least one instruction or a protocol or a parameter for the proposed function, process, and / or method. The memory 1230 may include read-only memory (ROM) and / or random access memory (RAM) and / or hard disk and / or CD-ROM and / or DVD and / or other storage devices.

[0334] Figure 13 illustrates a user equipment (UE) according to embodiments of the present disclosure.

[0335] Referring to the Figure 13, the UE 1300 may include a processor (or controller) 1310, a transceiver 1320 and a memory 1330. However, all of the illustrated components are not essential. The UE 1300 may be implemented by more or less components than those illustrated in Figure 13. In addition, the processor 1310 and the transceiver 1320 and the memory 1330 may be implemented as a single chip according to another embodiment.

[0336] The aforementioned components will now be described in detail.

[0337] The processor 1310 may include one or more processors or other processing devices that control the proposed function, process, and / or method. The operations described in Figures 1 to 11 of the UE 1300 may be implemented by the processor 1310.

[0338] The transceiver 1320 may include a RF transmitter for up-converting and amplifying a transmitted signal, and a RF receiver for down-converting a frequency of a received signal. However, according to another embodiment, the transceiver 1320 may be implemented by more or less components than those illustrated in components.

[0339] The transceiver 1320 may be connected to the processor 1310 and transmit and / or receive a signal. The signal may include control information and data. In addition, the transceiver 1320 may receive the signal through a wireless channel and output the signal to the processor 1310. The transceiver 1320 may transmit a signal output from the processor 1310 through the wireless channel.

[0340] The memory 1330 may store the control information or the data included in a signal obtained by the UE 1300. The memory 1330 may be connected to the processor 1310 and store at least one instruction or a protocol or a parameter for the proposed function, process, and / or method. The memory 1330 may include read-only memory (ROM) and / or random access memory (RAM) and / or hard disk and / or CD-ROM and / or DVD and / or other storage devices.

[0341] Certain examples of the present disclosure may be provided in the form of a base station (e.g. gNB) and / or method therefore. Certain examples of the present disclosure may be provided in the form of a mobile device (e.g. UE) and / or method therefore. Certain examples of the present disclosure may be provided in the form of a system comprising one or more base stations and one or more mobile devices, and / or method therefore.

[0342] The techniques described herein may be implemented using any suitably configured apparatus and / or system. Such an apparatus and / or system may be configured to perform a method according to any aspect, embodiment, example or claim disclosed herein. Such an apparatus may comprise one or more elements, for example one or more of receivers, transmitters, transceivers, processors, controllers, modules, units, and the like, each element configured to perform one or more corresponding processes, operations and / or method steps for implementing the techniques described herein. For example, an operation / function of X may be performed by a module configured to perform X (or an X-module). The one or more elements may be implemented in the form of hardware, software, or any combination of hardware and software.

[0343] 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 storage, for example a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape or the like.

[0344] It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs comprising instructions that, when executed, implement certain examples of the present disclosure. Accordingly, certain examples provide a program comprising 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. Still further, such programs may be conveyed electronically via any medium, for example a communication signal carried over a wired or wireless connection.

[0345] While the invention has been shown and described with reference to certain examples, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention, as defined by the appended claims.

Claims

1.A method performed by a user equipment (UE) in a wireless communication system, the method comprising:receiving a message including measurement object information;performing a neighbour cell measurement based on the measurement object information; andtransmitting a measurement report based on the neighbour cell measurement,wherein the measurement object information includes:a first list of configurations, in which each entry includes a cell index, a physical cell identifier (ID), and cell individual offset information, anda second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.2.The method of claim 1, wherein the second list of configurations has a same number of entries, listed in a same order, as in the first list of configurations.3.The method of claim 1, further comprising:transmitting UE capability information including information associated with a measuring of a non-terrestrial network (NTN) cell in radio resource control (RRC) connected state.4.The method of claim 3, wherein the message is an RRC connection reconfiguration message, and the neighbour cell measurement is performed in RRC connected state.5.The method of claim 1, wherein the neighbour cell measurement includes at least one of a measurement of an inter radio access technology (RAT) cell or a measurement of an intra RAT cell.6.The method of claim 1, wherein the neighbour cell measurement is performed while being connected to a non-terrestrial network (NTN) or a terrestrial network (TN).7.A method performed by a base station in a wireless communication system, the method comprising:transmitting a message including measurement object information; andreceiving a measurement report for a neighbour cell measurement associated with the measurement object information,wherein the measurement object information includes:a first list of configurations, in which each entry includes a cell index, a physical cell identifier (ID), and cell individual offset information, anda second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.8.The method of claim 7, wherein the second list of configurations has a same number of entries, listed in a same order, as in the first list of configurations.9.A user equipment (UE) in a wireless communication system, the UE comprising:a transceiver; andat least one processor configured to:receive, via the transceiver, a message including measurement object information,perform a neighbour cell measurement based on the measurement object information, andtransmit, via the transceiver, a measurement report based on the neighbour cell measurement,wherein the measurement object information includes:a first list of configurations, in which each entry includes a cell index, a physical cell identifier (ID), and cell individual offset information, anda second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.10.The UE of claim 9, wherein the second list of configurations has a same number of entries, listed in a same order, as in the first list of configurations.11.The UE of claim 9, wherein the at least one processor is further configured to transmit, via the transceiver, UE capability information including information associated with a measuring of a non-terrestrial network (NTN) cell in radio resource control (RRC) connected state.12.The UE of claim 11, wherein the message is an RRC connection reconfiguration message, and the neighbour cell measurement is performed in RRC connected state.13.The UE of claim 9, wherein the neighbour cell measurement includes at least one of a measurement of an inter radio access technology (RAT) cell or a measurement of an intra RAT cell.14.The UE of claim 9, wherein the neighbour cell measurement is performed while being connected to a non-terrestrial network (NTN) or a terrestrial network (TN).15.A base station in a wireless communication system, the base station comprising:a transceiver; andat least one processor configured to:transmit, via the transceiver, a message including measurement object information, andreceive, via the transceiver, a measurement report for a neighbour cell measurement associated with the measurement object information,wherein the measurement object information includes:a first list of configurations, in which each entry includes a cell index, a physical cell identifier (ID), and cell individual offset information, anda second list of configurations, in which each entry includes a satellite ID for a cell, used to associate with satellite assistance information for the neighbour cell measurement.

Images