Method for air-to-ground event evaluation

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. According to various examples of the present disclosure, there is provided a network entity for communication in an air-to-ground (ATG) network, and a method for a network entity for communication in an ATG network. The network entity is configured to calculate at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as a geodetic distance; evaluate whether a condition is satisfied based on the at least one calculated distance; and based on a result of the evaluation, control an operation relating to measurement; wherein each of the at least one reference location is located on the surface of the earth.

Description

METHOD FOR AIR-TO-GROUND EVENT EVALUATION

[0001] The present disclosure relates to the field of wireless communication networks. Particularly, the present disclosure relates to the evaluating a distance for event triggering and / or idle mode cell reselection measurement initiation in an Air-to-Ground (ATG) network, for example a 3rdGeneration Partnership Project (3GPP) 5thGeneration (5G) New Radio (NR) network.

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

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

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

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

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

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

[0008] The present disclosure relates to providing a method and system for evaluating a distance for event triggering and idle mode cell reselection measurement initiation in an ATG network, addressing the limitations of signal strength-based approaches.

[0009] 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.

[0010] 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.

[0011] According to an aspect of the present disclosure, there is provided a network entity for communicating in an air-to-ground (ATG) network, the network entity configured to: calculate at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as a geodetic distance; evaluate whether a condition is satisfied based on the at least one calculated distance; and based on a result of the evaluation, control an operation relating to measurement; wherein each of the at least one reference location is located on the surface of the earth.

[0012] According to various examples, calculating the at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as the geodetic distance comprises: calculating a first distance, among the at least one calculated distance, relating to the network entity and a first reference location, among the at least one reference location, and calculating a second distance, among the at least one calculated distance, relating to the network entity and a second reference location, among the at least one reference location; and wherein the condition is satisfied when: the first distance is greater than a first threshold and the second distance is less than a second threshold; the first distance is less than the first threshold; the second distance is greater than the second threshold; a first value equal to the first distance minus a hysteresis parameter is greater than the first threshold, and a second value equal to the second distance plus the hysteresis parameter is less than the second threshold; a third value equal to the first distance plus the hysteresis parameter is less than the first threshold; or a fourth value equal to the second distance minus the hysteresis parameter is greater than the second threshold.

[0013] According to various examples, controlling an operation relating to measurement comprises: when the condition is satisfied, triggering a measurement report for a connected mode process.

[0014] According to various examples, the connected mode process is a handover, and / or wherein the network entity is configured to transmit the measurement report.

[0015] According to various examples, one or more of the first threshold, the second threshold, the first reference location, the second reference location or the hysteresis parameter are configured for the network entity (e.g. by a base station).

[0016] According to various examples, the condition is associated with an event including one of: Event D1, Event D2, CondEvent D1 or CondEvent D2.

[0017] According to various examples, calculating the at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as the geodetic distance comprises: calculating a distance relating to the network entity and a reference location; and wherein the condition is satisfied when: the distance is less than a threshold.

[0018] According to various examples, controlling an operation relating to measurement comprises one of: when the condition is satisfied, determining to access a cell; when the condition is satisfied, not performing intra-frequency measurements, measurements of NR inter-frequency cells of equal or lower priority, or measurements of inter-RAT frequency cells of lower priority, for an idle or inactive mode process; or when the condition is not satisfied, performing intra-frequency measurements, measurements of NR inter-frequency cells of equal or lower priority, or measurements of inter-RAT frequency cells of lower priority, for an idle or inactive mode process.

[0019] According to various examples, the idle or inactive mode process is cell reselection.

[0020] According to various examples, the reference location and / or the threshold is received by broadcast.

[0021] According to various examples, calculating the at least one distance relating to the network entity and the at least one reference location, based on the at least one distance being configured as the geodetic distance, comprises one of: for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at a height of the network entity; for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at a height of said reference location; for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at a height of a base station (e.g. gNB); for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity said the reference location at a height in the middle between the network entity and said reference entity; for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at the respective height of the network entity and said reference entity; and for each reference location of the at least one reference location, calculating the geodesic distance between a location of the network entity and said reference location.

[0022] According to various examples, the location of the network entity is derived via global navigation satellite system (GNSS) measurement and / or an inertial navigation system.

[0023] According to various examples, the geodetic distance is a geodesic distance, a spherical distance, a Great-circle distance, an orthrodromic distance or a geographical distance.

[0024] According to various examples, the network entity is further configured to: receive, from a base station, information configuring the distance.

[0025] According to various examples, the received information configures one or more of: the distance as the geodetic distance, a height at which the distance is to be calculated and the at least one reference location; and / or wherein the received information configures the distance as the geodetic distance or the Euclidean distance for a specific use case.

[0026] According to various examples, the received information configures the distance as a Euclidean distance; and wherein the network entity is configured to calculate the at least one distance relating to the network entity and the at least one reference location, based on the at least one distance being configured as the euclidean distance.

[0027] According to various examples, calculating the at least one distance relating to the network entity and the at least one reference location, based on the at least one distance being configured as the euclidean distance comprises: for each reference location, calculating the euclidean distance between said reference location and a location on the ground above which the network entity is located.

[0028] According to various examples, the location on the ground above which the network entity is located corresponds to the geodetic coordinates of the network entity.

[0029] According to various examples, the network entity is an ATG UE.

[0030] According to another aspect of the present disclosure, there is provided a method of a network entity for communication in an air-to-ground (ATG) network, the method comprising: calculating at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as a geodetic distance; evaluating whether a condition is satisfied based on the at least one calculated distance; and based on a result of the evaluation, controlling an operation relating to measurement; wherein each of the at least one reference location is located on the surface of the earth.

[0031] According to various examples, calculating the at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as the geodetic distance comprises: calculating a first distance, among the at least one calculated distance, relating to the network entity and a first reference location, among the at least one reference location, and calculating a second distance, among the at least one calculated distance, relating to the network entity and a second reference location, among the at least one reference location; and wherein the condition is satisfied when: the first distance is greater than a first threshold and the second distance is less than a second threshold; the first distance is less than the first threshold; the second distance is greater than the second threshold; a first value equal to the first distance minus a hysteresis parameter is greater than the first threshold, and a second value equal to the second distance plus the hysteresis parameter is less than the second threshold; a third value equal to the first distance plus the hysteresis parameter is less than the first threshold; or a fourth value equal to the second distance minus the hysteresis parameter is greater than the second threshold.

[0032] According to various examples, calculating the at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as the geodetic distance comprises: calculating a distance relating to the network entity and a reference location; and wherein the condition is satisfied when: the distance is less than a threshold.

[0033] According to various examples, calculating the at least one distance relating to the network entity and the at least one reference location, based on the at least one distance being configured as the geodetic distance, comprises one of: for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at a height of the network entity; for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at a height of said reference location; for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at a height of a base station (e.g. gNB); for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity said the reference location at a height in the middle between the network entity and said reference entity; for each reference location of the at least one reference location, calculating the geodetic distance between a location of the network entity and said reference location at the respective height of the network entity and said reference entity; and for each reference location of the at least one reference location, calculating the geodesic distance between a location of the network entity and said reference location.

[0034] According to various examples, the method further comprises receiving, from a base station, information configuring the distance; and wherein the received information configures: one or more of: the distance as the geodetic distance, a height at which the distance is to be calculated and the at least one reference location; and / or the distance as the geodetic distance or the Euclidean distance for a specific use case.

[0035] According to various examples, the method is in accordance with any of the examples relating to the network entity given above.

[0036] According to another aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium configured to store instructions which, when executed by at least one processor or a computer, cause the at least one processor or computer to perform a method according to any one of the aspect or examples given above.

[0037] The methods and systems provided by the present disclosure enable efficient evaluation of a distance for event triggering and idle mode cell reselection measurement initiation in an ATG network, reducing unnecessary measurements and optimizing mobility management.

[0038] 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.

[0039] Figure 1 illustrates an exemplary Non-Terrestrial Network;

[0040] Figure 2 illustrates an exemplary Air-To-Ground network;

[0041] Figure 3 illustrates an exemplary Handover procedure;

[0042] Figure 4 illustrates exemplary EventD1 and CondEventD1 evaluations;

[0043] Figure 5 illustrates a cross-section of the earth in the plane of a reference location and ATG UE, where a distance threshold, if distance is computed using Euclidean distance, is shown;

[0044] Figure 6 illustrates various examples of calculating spherical distance;

[0045] Figure 7 illustrates an exemplary technique for measurement configuration and measurement reporting using the spherical distance between ATG UE and reference location in an ATG network;

[0046] Figure 8 illustrates various examples of calculating a distance using Euclidean distance of geodetic coordinates; and

[0047] Figure 9 is a block diagram of an exemplary network entity that may be used in certain examples of the present disclosure.

[0048] Figure 10 is a method flow diagram illustrating a method in accordance with an example of the present disclosure.

[0049] Herein, the following documents may be referenced and the contents thereof are incorporated into the present disclosure:

[0050] [1] 3GPP TS 38.331, "Radio Resource Control (RRC) protocol specification (Release 17)", Release 17 (V17.7.0), December 2023.

[0051] [2] 3GPP TS 38.331, "Radio Resource Control (RRC) protocol specification (Release 18)", Release 18 (V18.0.0), December 2023.

[0052] [3] 3GPP TS 38.304, "User Equipment (UE) procedures in Idle mode and RRC inactive state (Release 18)", Release 18 (V18.0.0), December 2023.

[0053] [4] Military Standard WGS84 Metric MIL-STD-2401: "Military Standard Department of Defence World Geodetic System (WGS)", 11 January 1994.

[0054] Various acronyms, abbreviations and definitions used in the present disclosure are defined at the end of this description.

[0055] Overview of Non-Terrestrial Network

[0056] NR NTN (NR_NTN_solutions-Core) [RP-211557] was a 3GPP Work Item in 3GPP Release 17 to define solution enable New Radio (NR) and NG-RAN support Non-Terrestrial Networks. It addressed solution for Transparent payload for both Geostationary and non-Geostationary network scenarios, with the UE having GNSS capability and the satellite beams being both earth-fixed or earth-moving.

[0057] IoT NTN was a 3GPP study and work item in 3GPP release 17 to provide Non-Terrestrial Network access for E-UTRAN IoT devices (NB-IoT and LTE-M / eMTC) [RP-202689]. NR NTN was a work item in Rel-17 to specify adaptation to allow NR to function over NTN [RP-211557]. Non-Terrestrial Network access may be through Lower Earth Orbit (LEO), Medium Earth Orbit (MEO) and Geostationary Orbit (GEO), as well as through High-Altitude Platform Systems (HAPS).

[0058] Following the Work items in Release 17 there were work items to enhance NR NTN [RP-220953] and IoT NTN [RP-220979] in Release 18.

[0059] NR NTN enhancements [RP-222654] is a 3GPP Work Item in 3GPP Release 18 aiming to enhance NR NTN with the following topics:

[0060] 1.Coverage enhancements: Identifying and specifying potential issues and enhancements considering NTN characteristics.

[0061] 2.NR NTN deployment in above 10 GHz bands: NR NTN Release 17 did not have support for FR2 due to there being no PRACH format in FR2 for FDD.

[0062] 3.Network verified UE location

[0063] 4.NTN-TN and NTN-NTN mobility and service continuity enhancements: Considers NTN-TN and NTN-NTN measurement / mobility and service continuity enhancements.

[0064] Overview of Synchronization operation in NTN

[0065] Synchronization in NR NTN is partly achieved by the UE computing the distance between the UE and the NTN node. To do this the UE needs to know its own position as well as the position of the satellite. UE acquires its own position through GNSS and the satellite position through what is known as satellite ephemeris element broadcasted in System Information. As both UE and satellite may move, this is maintained in two ways, through 1) maintaining an accurate GNSS position, 2) maintaining a recent ephemeris element of the serving satellite.

[0066] In NR NTN, the satellite ephemeris is broadcasted in system information block SIB19. This element needs to be acquired every time the UE attempts to connect to an NTN cell. SIB19 also contain neighbour cell assistance information.

[0067] In IoT NTN the serving cell ephemeris element is sent in system information in an element known as SIB31 and in order to make sure that the UE is correctly synchronized, this element needs to be read every time it connects to an IoT NTN eNB.

[0068] Overview of Air-To-Ground network

[0069] An Air-To-Ground (ATG / A2G) network is a cellular network that provides connectivity in the air via base stations on the ground. It is different from a Non-Terrestrial Network as the access link is from the ground to the UE in the sky, whereas in NTN the access link is from space / sky to the ground, as seen in Figure 2.

[0070] One of the main use cases of A2G network is to provide backhaul connectivity to access points in aircraft.

[0071] A Study item was started in Rel-18 [RP-221369] in RAN4 to define requirements for coexistence between ATG and IMT terrestrial networks. Furthermore, to define RRM performance requirements for ATG UE, demodulation performance requirements for ATG BS / UE, and test procedures for ATG BS conformance testing.

[0072] The Air-To-Ground network is similar to a non-terrestrial network in the sense that the cells can be very large, synchronization will have to be different and that there are network elements that may move very quickly.

[0073] Some of the characteristics from an RF point of view of an ATG network are spelled out in [RP-221369]:

[0074] 1. Extremely large inter-site distances and large coverage range.

[0075] 2. Utilizing non-disjoint frequency for deploying both ATG and terrestrial networks.

[0076] 3. Much more powerful on-board ATG terminal capacity.

[0077] Overview of Air-to-Ground system information

[0078] In order to allow for an ATG-capable UE to connect to an ATG cell, the UE needs certain information, similar to NR NTN.

[0079] In ATG the UE is provided via system information in SIB22 with the following information:

[0080] - ATG-Config, which contains the following information:

[0081] o atg-gNB-Location and heightgNB, which is required in order for a UE to synchronize with the ATG cell. Atg-gNB-Location is a reference location that define a coordinate on the surface of the earth, while the height is the a number in the granularity of a meter. Both elements may be purposefully obscured, i.e. not showing the true position, in order to not give up the precise location of the gNB, which can be sensitive information for a network operator.

[0082] o Cell specific Koffset.

[0083] o Ta-ReportATG - This indicates whether a Timing Advance Report MAC CE should be triggered, compiled and sent to the network under certain conditions such as during random access procedures, handovers and RRC connection establishment, RRC Resume or RRC Connection re-establishment.

[0084] The above set of parameters may be referred to as "ATG assistance information". However, one can expect that any future parameters that are included in ATG-Config would be characterized as ATG assistance information.

[0085] Overview of Connected mode mobility

[0086] 5G NR connected mode mobility functions similar to other cellular standards. A standard connected mode handover is performed only when triggered by the gNB.

[0087] The full usual procedure is as follows (with reference to Figure 3):

[0088] 1) A UE is configured with measurement configuration via RRCReconfiguration, which includes a MeasReportNR which instructs when a UE shall report measurements and also includes the MeasObjectNR which gives details on how to perform the measurement.

[0089] 2) UE performs neighbour cell measurements according to the measurement configuration, which are configured by the network.

[0090] 3a) A measurement report (of a neighbour cell) is triggered and, 3b) is sent to the gNB.

[0091] 4) Inter-node procedures 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.

[0092] 5) The Source eNB triggers a handover command which is sent to the UE. This handover command consists of the RRC messageRRCConnectionReconfiguration, containing themobilityControlInfofield.

[0093] 6) UE prepares for handover and performs a handover via the random access procedure.

[0094] 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 shall perform in RRC connected. A measurement object is related to an either a frequency or a RAT. There are for instance intra-RAT NR Measurement object (MeasObjectNR), which may configure intra or inter-frequency measurements. The MeasObjectNR contains configurations such as the carrier frequency, measurement bandwidth, SSB configurations, 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 E-UTRAN (MeasObjectEUTRA), UTRA (MeasObjectUTRA), GERAN (MeasObjectGERAN), CDMA2000 (MeasObjectCDMA2000), or WLAN (MeasObjectWLAN).

[0095] The measurement reporting configuration (ReportConfigNR) contains rules that define when a measurement report containing measurements shall be sent. These are typically defined by measurement reporting triggering conditions (also called measurement events), thresholds, and configuring what measure shall be reported.

[0096] Overview of Connected mode measurement events

[0097] In order to trigger the measurement reporting, there are a set of measurement events that give specific conditions on when a measurement report shall be sent.

[0098] A set of such well-known examples are the A1 to A5 events. These are defined as follows:

[0099] - Event A1 (Serving becomes better than a threshold)

[0100] - Event A2 (Serving becomes worse than a threshold)

[0101] - Event A3 (Neighbour becomes offset better than Serving)

[0102] - Event A4 (Neighbour becomes better than threshold)

[0103] - Event A5 (SpCell becomes worse than threshold1 and neighbour becomes better than threshold2)

[0104] The signal type that is measured can either be the Reference Signal Received Power (RSRP) which is the absolute strength of a measured signal, or the Reference Signal Received Quality (RSRQ) which is the relative strength of a measure signal compared to noise and interference.

[0105] Event A3 should can thus be configured to be "Neighbour cell RSRP becomes a configured offset better than Serving cell RSRP"

[0106] For an event, there will be an entering and leaving condition, and a time during which the entering or leaving condition shall be true (timeToTrigger) before the measurement report is triggered. This to prevent frequent triggered measurement reports.

[0107] For instance for event A1 the entering condition is "Ms - Hys > Thresh", and the leaving condition is "Ms + Hys < Thresh", where Ms is the measurement result of the serving cell, Hys is the configured hysteresis parameter, and Thresh is the configured threshold.

[0108] In NTN Release 17, there were new events introduced that instead of relying on radio signals utilize the position of a UE.

[0109] Event D1 is defined as "Distance between UE and referenceLocation1 is above threshold1 and distance between UE and referenceLocation2 is below threshold2". The event thus has two entering conditions that must be satisfied "distance between UE and referenceLocation1 is above threshold1" and "distance between UE and referenceLocation2 is below threshold2". Similarly, the leaving conditions, where at least one must be true, is "distance between UE and referenceLocation1 is below threshold1" and "distance between UE and referenceLocation2 is above threshold2". Similarly the entering and leaving conditions include an hysteresis. This can be seen in Figure 4.

[0110] The event is defined as below in 3GPP TS 38.331:

[0111] 5.5.4.15 Event D1 (Distance between UE and referenceLocation1 is above threshold1 and distance between UE and referenceLocation2 is below threshold2)

[0112] The UE shall:

[0113] 1> consider the entering condition for this event to be satisfied when both condition D1-1 and condition D1-2, as specified below, are fulfilled;

[0114] 1> consider the leaving condition for this event to be satisfied when condition D1-3 or condition D1-4, i.e. at least one of the two, as specified below, are fulfilled;

[0115] Inequality D1-1 (Entering condition 1)

[0116] Ml1-Hys>Thresh1

[0117] Inequality D1-2 (Entering condition 2)

[0118] Ml2+Hys<Thresh2

[0119] Inequality D1-3 (Leaving condition 1)

[0120] Ml1+Hys<Thresh1

[0121] Inequality D1-4 (Leaving condition 2)

[0122] Ml2-Hys>Thresh2

[0123] The variables in the formula are defined as follows:

[0124] Ml1is the distance between UE and a reference location for this event (i.e.referenceLocation1as defined withinreportConfigNRfor this event), not taking into account any offsets.

[0125] Ml2is the distance between UE and a reference location for this event (i.e.referenceLocation2as defined withinreportConfigNRfor this event), not taking into account any offsets.

[0126] Hysis the hysteresis parameter for this event (i.e.hysteresisLocationas defined withinreportConfigNRfor this event).

[0127] Thresh1is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference1,from a reference location configured with parameterreferenceLocation1withinreportConfigNRfor this event.

[0128] Thresh2is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference2,from a reference location configured with parameterreferenceLocation2withinreportConfigNRfor this event.

[0129] Ml1is expressed in meters.

[0130] Ml2is expressed in the same unit asMl1.

[0131] Hysis expressed in the same unit asMl1.

[0132] Thresh1is expressed in the same unit asMl1.

[0133] Thresh2is expressed in the same unit asMl1.

[0134] NOTE: The definition of Event D1 also applies to CondEvent D1.

[0135] Furthermore, CondEvent D2 is similar to CondEvent D1, where the CondEvent D2 allows for the reference location to move along the surface of the earth. This is useful in an earth-moving cell NTN network, where the cells sweep the surface of the earth as the satellites move. CondEvent D1 is more suitable for quasi-earth fixed or fixed cell case, which is very the cell is either fully fixed on the ground for stationary satellites, or momentarily fixed on the ground as the satellite moves.

[0136] Overview of Idle and inactive mode mobility

[0137] Idle and inactive mode mobility is based on a UE autonomously performing measurements and deciding according to some rules whether a UE shall re-select to another cell or not to camp on.

[0138] During cell selection, the UE identifies suitable cells, which is according to a cell suitability criteria based on signal strength and signal quality measurements. After identifying one or several suitable cells, the UE can choose any of them.

[0139] During cell re-selection, the UE searches intra-frequency cells, inter-frequencies cells and inter-RAT cells. Each frequency will have a specific cell reselection priority, and the UE shall always choose a cell of highest priority, given that it is not barred or not allowed to camp on. If cells of equal priority is detected, then the UE shall rank all of the cells, where the ranking metric is based on signal strength and signal quality measurements, and then choose the best candidate. The UE then camps on the newly re-selected cell.

[0140] In NR NTN, an enhancement to have the measurement initiated based on distance was introduced. For this enhancement, the UE is allowed to not perform measurements of NR and inter-RAT frequencies of equal or lower priority if the distance from the UE to a reference location is smaller than a threshold. Else the UE shall perform measurement of NR and inter-RAT frequencies of equal or lower priority. The distance threshold and the reference location is broadcasted by the network. For moving cell cases, where the cell sweeps the earth as the satellite moves, there is the possibility of configuring the reference location to moving. The condition is still the same, only that the reference location moves. In both of these cases, the non-NTN condition needs to be fulfilled, i.e. that the received signal strength level (Srxlev) is larger than SnonIntraSearchP and the received signal quality level is larger than SnonIntraSearchQ.

[0141] 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.

[0142] 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.

[0143] The same or similar components may be designated by the same or similar reference numerals, although they may be illustrated in different drawings.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] The skilled person will appreciate that the techniques described herein may be used in any suitable combination.

[0151] Certain examples of the present disclosure provide one or more techniques for evaluating a distance for event triggering and / or idle mode cell reselection measurement initiation in an ATG network, for example a 3GPP 5G NR network. 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 6thGeneration (6G).

[0152] 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.

[0153] 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.

[0154] 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.

[0155] The skilled person will appreciate that the present invention is not limited to the specific examples disclosed herein. For example:

[0156] · The techniques disclosed herein are not limited to 3GPP 5G.

[0157] · 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.

[0158] · 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.

[0159] · One or more further elements or entities may be added to the examples disclosed herein.

[0160] · One or more non-essential elements or entities may be omitted in certain examples.

[0161] · 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.

[0162] · 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.

[0163] · Information carried by a particular message in one example may be carried by two or more separate messages in an alternative example.

[0164] · Information carried by two or more separate messages in one example may be carried by a single message in an alternative example.

[0165] · The order in which operations are performed and / or the order in which messages are transmitted may be modified, if possible, in alternative examples.

[0166] 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.

[0167] Certain examples of the present disclosure provide a UE / base station (e.g. eNB, gNB) / network entity (e.g. AMF, SMF, NF) configured to perform a method according to any example, aspect, embodiment and / or claim disclosed herein.

[0168] Certain examples of the present disclosure provide a network (or wireless communication system) comprising a UE, base station (e.g. eNB, gNB) and / or one or more other network entities (e.g. AMF, SMF, NF) according to any examples, aspects, embodiments and / or claims disclosed herein.

[0169] 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.

[0170] 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.

[0171] For NTN and other scenarios where there are large cells, the location of the UE may sometimes be a more reliable indication of required mobility compared to signal strength.

[0172] Due to this, enhancements were introduced; 1) where a measurement report may be triggered based on the location for connected mode mobility purposes, and 2) where the UE would be triggered to perform measurements of certain cells or frequencies based on the distance.

[0173] However, it is not clear how this distance is measured. When synchronizing to a network using the ATG location (and NTN node location) and the UE location, the UE needs to use the Euclidean distance. This is because the propagation delay and the doppler frequency offset needs to be calculated.

[0174] However, for calculating the distance for the purpose of measurement reporting and idle / inactive mode measurement initiation, it is not as clear what distance shall be used. If for instance the Euclidean distance is used, when the UE is operating in the sky, the area for a specific condition will be as seen in Figure 4. This is likely not the shape that one would like to achieve in an ATG network.

[0175] Certain examples of the present disclosure provide one or more techniques for evaluating a distance for event triggering and idle mode cell reselection measurement initiation in an ATG network.

[0176] In the present disclosure, the term "network" may be used as a shorthand for "ATG network" in certain contexts. Therefore, the term "network" should not be taken to mean "non-ATG network".

[0177] The skilled person will appreciate that any suitable type of base station may be used in the examples disclosed herein, for example gNB, BS, eNB, NG-RAN, NG-eNB or similar, and that these terms may be used interchangeably in various examples. The skilled person will appreciate that the techniques disclosed herein may be applied not only to 5G NR, but also to 4G E-UTRAN, including IoT technologies such as eMTC and / or NB-IoT. For example, the techniques disclosed herein may be applied to IoT NTN, which is based on 4G E-UTRAN.

[0178] The skilled person will appreciate that any suitable type of wireless device may be used in the examples disclosed herein. In the present disclosure, and in certain parts of the specifications, the term "UE" may be used as a shorthand for "ATG UE" in certain contexts. Therefore, the term "UE" should not be taken to mean "non-ATG UE". The term "ATG UE" may also be considered to include "ATG-capable UE"

[0179] The skilled person will appreciate that any suitable definition of distance may be used in various examples of the present disclosure. For example, spherical distance may be replaced by any other suitable equivalent or similar distance, for example "Great-circle distance" and "orthrodromic distance" or close, such as "geodetic distance", "geodesic distance" and "geographical distance".

[0180] In certain examples, the associated elevation may be used for one or more of the following in any suitable combination:

[0181] - Evaluating any measurement event or conditional measurement event that involves the distance:

[0182] o Event D1

[0183] o Event D2

[0184] o CondEvent D1

[0185] o CondEvent D2

[0186] o This means that if the spherical distance or any other distance defined in this invention fulfils one or more criteria, the UE will send a measurement report.

[0187] - Evaluating other procedures that requires the distance:

[0188] o Evaluating measurement triggering in idle and inactive mode (as introduced in NTN).

[0189] § This means that if the spherical distance or any other distance defined in this invention is shorter than a threshold (distanceThresh), then the UE may not perform intra-frequency measurements, or measurement of inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority.

[0190] § Otherwise, if the spherical distance or any other distance defined in this invention is larger than a threshold, then the UE shall perform intra-frequency measurements, or measurement of inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority.

[0191] o Deciding whether a UE is allowed to access a cell. For instance, if a UE shall only access a cell whether it is below or above a certain distance threshold.

[0192] § For instance a UE may be configured to only access a cell if it is within 10 kilometer of a specific reference location.

[0193] The reference locations and distances may be calculated using any suitable framework, for example the standard World Geodetic System 84 (WGS84) [4]. The height may also be referred to as elevation, or geodetic or geodesic elevation. "Sea level" may be taken as "Mean Sea level" or geodetic elevation = 0 or ellipsoidal height = 0 or geoid height, as is used in Global Positioning System (GPS). Sea level may also mean the geoid, i.e. the earth reference surface as defined by a set of parameters, as defined by the standard WGS84, or any other standard.

[0194] "Height" of the ATG UE may be understood, for example, as the vertical position or component, as the elevation, the ellipsoid height, or as the geodetic height.

[0195] Various examples of the present disclosure will now be described in more detail.

[0196] Evaluating an event or condition based on spherical distance for ATG

[0197] In certain examples, the distance may be evaluated based on the spherical distance between a ATG UE and a reference location.

[0198] The spherical distance may be calculated in a number of manners which may have impact on when the event is triggered.

[0199] In a refinement of how the distance is calculated, the ATG UE calculates the distance using the spherical distance between the UE and a reference location at the sea level. In other words, the height of the UE and the reference location is not taken into account and are thus evaluated at the height above the sea level. How the cross-section looks like can be seen in Figure 6a. This is sometimes referred as a geodetic distance.

[0200] Exemplary procedures for calculating the above include one or more of the following:

[0201] In certain examples, the ATG UE calculates the spherical distance between the UE and a reference location at the height of the UE. How the cross-section looks like can be seen in Figure 6b.

[0202] In certain examples, the ATG UE calculates the distance of the spherical distance between the UE and a reference location at the height of the reference location.

[0203] In certain examples, the ATG UE calculates the distance of the spherical distance between the UE and a reference location at the height of the gNB. The height of the gNB is broadcasted in order to allow for an ATG UE to synchronize with a gNB.

[0204] In certain examples, the ATG UE calculates the distance of the spherical distance between the UE and a reference location at height in the middle between the reference and the UE location. How the cross-section looks like can be seen in Figure 6c.

[0205] In certain examples, the ATG UE calculates the distance of the spherical distance between the UE and a reference location at the respective height of the ATG UE and the reference location. How the cross-section looks like can be seen in Figure 6d.

[0206] In certain examples, the ATG UE calculates what is known as the geodesic distance (sometimes known as geodetic distance) between the UE and a reference location. This is generally a distance that follows the surface of the earth, where the surface of the earth may be modelled in a number of ways, for instance using perfect spherical earth or ellipsoidal earth. This ellipsoidal earth surface may for instance be defined by the ellipsoid defined by the WGS84 standard. This means that the height (also known as vertical position or the elevation) of the ATG UE is not accounted for.

[0207] An example in Figure 7 shows how the ATG UE is configured and triggers the measurement report.

[0208] An example of how to specify this for measurement triggering evaluation can be seen in Specification Example 1 further below, and an example how to specify this for idle or inactive mode can be seen in Specification Example 2 further below.

[0209] Evaluating an event or condition based on Euclidean distance for ATG

[0210] In certain examples, the event is evaluated based on a specialized Euclidean distance between the ATG UE and a reference location. In this specific case, not Euclidean distance that is calculated is between the ATG UE location on the ground and a reference location. Thus the height component of the position is not included when calculating the Euclidean distance, i.e. only the longitude and latitude is used when computing the Euclidean distance. In other words, the distance is calculated based on the UE's geodetic coordinates and the reference location. This can be seen in Figure 8.

[0211] Further aspects

[0212] In certain examples, the gNB may configure which type of distance that shall be used when computing the distance. For example, it may configure whether spherical distance (which, as indicated above, may be regarded as the geodesic or geodetic distance), or Euclidean distance shall be used. If not configured, it may for instance be default for a specific use case. For example, for ATG the default if not configured may for instance be Euclidean distance or spherical distance. This may be configured, e.g. by a base station, for the measurement event if it is used for measurement event triggering, or it may be configured in any idle and / or inactive mode configuration if the distance evaluation is used in idle or inactive mode measurement triggering.

[0213] For example, with this configuration this means that the UE calculates the distance(s) according to the received base station configuration.

[0214] In one example, if the network configures the UE to use geodetic distance in a measurement configuration, the UE evaluates and potentially triggers a measurement report according to the evaluated geodetic distance(s). If the network configures the UE to use euclidean distance, then the UE evaluates and potentially triggers a measurement report according to the evaluated euclidean distance(s).

[0215] In one example, if the network configures the UE to use geodetic distance in an idle and inactive mode measurement configuration, the UE evaluates the distance using geodetic distance in the idle mode procedures. If the network configures the UE to use euclidean distance, then the UE evaluates distance using euclidean distance in the idle mode procedures.

[0216] In certain examples, the gNB may configure the height at which the distance shall be computed. This may for instance may have one of the following options:

[0217] - Configuring one of the heights as sea-level, UE height, gNB height.

[0218] - Configuring a specific height in meters or any other suitable altitude or height, such as in feet or in flight level (FL).

[0219] This may be configured for the measurement event if it is used for measurement event triggering, or it may be configured in any idle and / or inactive mode configuration if the distance evaluation is used in idle or inactive mode measurement triggering.

[0220] The UE location used in the above evaluation may for instance be the GNSS location, for example a location that is derived via GNSS measurements. The UE location may also be derived from an inertial navigation system or a combination of GNSS and inertial navigation.

[0221] Specification Examples

[0222] A number of examples of how the existing specification may be modified to incorporate one or more of the above techniques will now be described. In the following examples, revisions are indicated with boldunderlineand bold[[double square brackets]]. The skilled person will appreciate that the changes in the following examples may be applied in any suitable combination.

[0223] Example 1a

[0224] 5.5.4.15 Event D1 (Distance between UE and referenceLocation1 is above threshold1 and distance between UE and referenceLocation2 is below threshold2)

[0225] The UE shall:

[0226] 1> consider the entering condition for this event to be satisfied when both condition D1-1 and condition D1-2, as specified below, are fulfilled;

[0227] 1> consider the leaving condition for this event to be satisfied when condition D1-3 or condition D1-4, i.e. at least one of the two, as specified below, are fulfilled;

[0228] Inequality D1-1 (Entering condition 1)

[0229] Ml1-Hys>Thresh1

[0230] Inequality D1-2 (Entering condition 2)

[0231] Ml2+Hys<Thresh2

[0232] Inequality D1-3 (Leaving condition 1)

[0233] Ml1+Hys<Thresh1

[0234] Inequality D1-4 (Leaving condition 2)

[0235] Ml2-Hys>Thresh2

[0236] The variables in the formula are defined as follows:

[0237] Ml1is the distance between UE and a reference location for this event (i.e.referenceLocation1as defined withinreportConfigNRfor this event), not taking into account any offsets.For ATG the distance between a UE and a reference location is the spherical distance at sea level.

[0238] Ml2is the distance between UE and a reference location for this event (i.e.referenceLocation2as defined withinreportConfigNRfor this event), not taking into account any offsets.For ATG the distance between a UE and a reference location is the spherical distance at sea level.

[0239] Hysis the hysteresis parameter for this event (i.e.hysteresisLocationas defined withinreportConfigNRfor this event).

[0240] Thresh1is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference1,from a reference location configured with parameterreferenceLocation1withinreportConfigNRfor this event.

[0241] Thresh2is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference2,from a reference location configured with parameterreferenceLocation2withinreportConfigNRfor this event.

[0242] Ml1is expressed in meters.

[0243] Ml2is expressed in the same unit asMl1.

[0244] Hysis expressed in the same unit asMl1.

[0245] Thresh1is expressed in the same unit asMl1.

[0246] Thresh2is expressed in the same unit asMl1.

[0247] NOTE: The definition of Event D1 also applies to CondEvent D1.

[0248] Example 1b

[0249] 5.5.4.15 Event D1 (Distance between UE and referenceLocation1 is above threshold1 and distance between UE and referenceLocation2 is below threshold2)

[0250] The UE shall:

[0251] 1> consider the entering condition for this event to be satisfied when both condition D1-1 and condition D1-2, as specified below, are fulfilled;

[0252] 1> consider the leaving condition for this event to be satisfied when condition D1-3 or condition D1-4, i.e. at least one of the two, as specified below, are fulfilled;

[0253] Inequality D1-1 (Entering condition 1)

[0254] Ml1-Hys>Thresh1

[0255] Inequality D1-2 (Entering condition 2)

[0256] Ml2+Hys<Thresh2

[0257] Inequality D1-3 (Leaving condition 1)

[0258] Ml1+Hys<Thresh1

[0259] Inequality D1-4 (Leaving condition 2)

[0260] Ml2-Hys>Thresh2

[0261] The variables in the formula are defined as follows:

[0262] Ml1is the distance between UE and a reference location for this event (i.e.referenceLocation1as defined withinreportConfigNRfor this event), not taking into account any offsets.For ATG the distance is the geodesic distance between the longitude and latitude of the UE and the reference location.

[0263] Ml2is the distance between UE and a reference location for this event (i.e.referenceLocation2as defined withinreportConfigNRfor this event), not taking into account any offsets.For ATG the distance is the geodesic distance between the longitude and latitude of the UE and the reference location.

[0264] Hysis the hysteresis parameter for this event (i.e.hysteresisLocationas defined withinreportConfigNRfor this event).

[0265] Thresh1is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference1,from a reference location configured with parameterreferenceLocation1withinreportConfigNRfor this event.

[0266] Thresh2is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference2,from a reference location configured with parameterreferenceLocation2withinreportConfigNRfor this event.

[0267] Ml1is expressed in meters.

[0268] Ml2is expressed in the same unit asMl1.

[0269] Hysis expressed in the same unit asMl1.

[0270] Thresh1is expressed in the same unit asMl1.

[0271] Thresh2is expressed in the same unit asMl1.

[0272] NOTE: The definition of Event D1 also applies to CondEvent D1.

[0273] Example 2

[0274] 5.2.4.2 Measurement rules for cell re-selection

[0275] Following rules are used by the UE to limit needed measurements:

[0276] - If the serving cell fulfils Srxlev> SIntraSearchPand Squal > SIntraSearchQ:

[0277] - IfdistanceThreshandreferenceLocationare broadcasted in SIB19or SIB22, and if UE supports location-based measurement initiation[[for NTN quasi-Earth-fixed system]]and has obtained its location information:

[0278] - For NTN quasi-Earth-fixed system:

[0279] - If the distance between UE and the serving cell reference locationreferenceLocationis shorter thandistanceThresh, the UE may not perform intra-frequency measurements;

[0280] - Else, the UE shall perform intra-frequency measurements;

[0281] - For ATG:

[0282] -If the spherical distance between UE and the serving cell reference locationreferenceLocationis shorter thandistanceThresh, the UE may not perform intra-frequency measurements;

[0283] -Else, the UE shall perform intra-frequency measurements;

[0284] - else ifdistanceThreshandmovingReferenceLocationare broadcasted in SIB19, and if UE supports location-based measurement initiation for NTN Earth-moving system and has obtained its location information:

[0285] - if the distance between UE's location and the serving cell reference location determined based onmovingReferenceLocationis shorter thandistanceThresh, the UE may not perform intra-frequency measurements;

[0286] - else, the UE shall perform intra-frequency measurements;

[0287] - Else, the UE may not perform intra-frequency measurements;

[0288] - Else, the UE shall perform intra-frequency measurements.

[0289] - The UE shall apply the following rules for NR inter-frequencies and inter-RAT frequencies which are indicated in system information and for which the UE has priority provided as defined in 5.2.4.1:

[0290] - For a NR inter-frequency or inter-RAT frequency with a reselection priority higher than the reselection priority of the current NR frequency, the UE shall perform measurements of higher priority NR inter-frequency or inter-RAT frequencies according to TS 38.133 [8].

[0291] - For a NR inter-frequency with an equal or lower reselection priority than the reselection priority of the current NR frequency and for inter-RAT frequency with lower reselection priority than the reselection priority of the current NR frequency:

[0292] - If the serving cell fulfils Srxlev > SnonIntraSearchPand Squal > SnonIntraSearchQ:

[0293] - IfdistanceThreshandreferenceLocationare broadcasted in SIB19and SIB22, and if UE supports location-based measurement initiation[[for NTN quasi-Earth-fixed system]]and has obtained its UE location information:

[0294] - For NTN quasi-Earth-fixed system:

[0295] - If the distance between UE and the serving cell reference locationreferenceLocationis shorter thandistanceThresh, the UE may choose not to perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority;

[0296] - Else, the UE shall perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority according to TS 38.133 [8];

[0297] - For ATG:

[0298] -If the spherical distance between UE and the serving cell reference locationreferenceLocationis shorter thandistanceThresh, the UE may choose not to perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority;

[0299] -Else, the UE shall perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority according to TS 38.133 [8];

[0300] - else ifdistanceThreshandmovingReferenceLocationare broadcasted in SIB19, and if UE supports location-based measurement initiation for NTN Earth-moving system and has obtained its location information:

[0301] - if the distance between UE's location and the serving cell reference location determined based onmovingReferenceLocationis shorter thandistanceThresh, the UE may not perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority;

[0302] - else, the UE shall perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority according to TS 38.133 [8];

[0303] - Else, the UE may choose not to perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority;

[0304] - Else,the UE shall perform measurements of NR inter-frequency cells of equal or lower priority, or inter-RAT frequency cells of lower priority according to TS 38.133 [8].

[0305] - If the UE supports relaxed measurement andrelaxedMeasurementis present inSIB2, the UE may further relax the needed measurements, as specified in clause 5.2.4.9.

[0306] - For UE camping on NTN cell, if the UE supports skipping TN measurement, and the UE has obtained its location information, and ifcoverageAreaInfoListandtn-AreaIdListare broadcast in system information, the UE may not perform measurements of a TN frequency when UE is not in the coverage of that frequency provided viatn-AreaIdList, regardless of the frequency priority.

[0307] If thet-Serviceof the serving cell is present in SIB19, and if UE supports time-based measurement initiation, the UE shall perform intra-frequency, inter-frequency or inter-RAT measurements before the t-Service, regardless of the distance between UE and the serving cell reference location or whether the serving cell fulfils Srxlev > SIntraSearchPand Squal > SIntraSearchQ, or Srxlev > SnonIntraSearchPand Squal > SnonIntraSearchQ, The exact time to start measurement beforet-Serviceis up to UE implementation. UE shall perform measurements of higher priority NR inter-frequency or inter-RAT frequencies according to TS 38.133 [8] regardless of the remaining service time of the serving cell (i.e. time remaining untilt-Service).

[0308] NOTE 1: When evaluating the distance between UE and the serving cell reference location, it's up to UE implementation to obtain UE location information.

[0309] NOTE 2: In the Earth-moving system, it's up to UE implementation to maintain a valid serving cell reference location, which is derived based on the serving satellite ephemeris,epochTimeandmovingReferenceLocation.

[0310] Example 3

[0311] ReportConfigNRinformation element

[0312]

[0313]

[0314]

[0315]

[0316]

[0317] CondTriggerConfigfield descriptions.. . OMITTED.. .condEventDX-DistanceEvaluationMethodIndicates how the distance shall be evaluated for condEvent D1 and condEvent D2. Field valuesphericalindicates that the distance shall be the spherical distance between the UE and the reference location. Field valueeuclideanindicates that the distance shall be the euclidean distance between the UE and the reference location... . OMITTED.. .EventTriggerConfigfield descriptions.. . OMITTED.. .eventDX-DistanceEvaluationMethodIndicates how the distance shall be evaluated for event D1 and event D2. Field valuesphericalindicates that the distance shall be the spherical distance between the UE and the reference location. Field valueeuclideanindicates that the distance shall be the euclidean distance between the UE and the reference location... . OMITTED.. .

[0318] Example 4

[0319] 5.5.4.15 Event D1 (Distance between UE and referenceLocation1 is above threshold1 and distance between UE and referenceLocation2 is below threshold2)

[0320] The UE shall:

[0321] 1> consider the entering condition for this event to be satisfied when both condition D1-1 and condition D1-2, as specified below, are fulfilled;

[0322] 1> consider the leaving condition for this event to be satisfied when condition D1-3 or condition D1-4, i.e. at least one of the two, as specified below, are fulfilled;

[0323] Inequality D1-1 (Entering condition 1)

[0324] Ml1-Hys>Thresh1

[0325] Inequality D1-2 (Entering condition 2)

[0326] Ml2+Hys<Thresh2

[0327] Inequality D1-3 (Leaving condition 1)

[0328] Ml1+Hys<Thresh1

[0329] Inequality D1-4 (Leaving condition 2)

[0330] Ml2-Hys>Thresh2

[0331] The variables in the formula are defined as follows:

[0332] Ml1is the distance between UE and a reference location for this event (i.e.referenceLocation1as defined withinreportConfigNRfor this event), not taking into account any offsets.For ATG the distance between a UE and a reference location is the euclidean distance between the UE geodetic coordinates and the reference location.

[0333] Ml2is the distance between UE and a reference location for this event (i.e.referenceLocation2as defined withinreportConfigNRfor this event), not taking into account any offsets.For ATG the distance between a UE and a reference location is the euclidean distance between the UE geodetic coordinates and the reference location.

[0334] Hysis the hysteresis parameter for this event (i.e.hysteresisLocationas defined withinreportConfigNRfor this event).

[0335] Thresh1is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference1,from a reference location configured with parameterreferenceLocation1withinreportConfigNRfor this event.

[0336] Thresh2is the threshold for this event defined as a distance, configured with parameterdistanceThreshFromReference2,from a reference location configured with parameterreferenceLocation2withinreportConfigNRfor this event.

[0337] Ml1is expressed in meters.

[0338] Ml2is expressed in the same unit asMl1.

[0339] Hysis expressed in the same unit asMl1.

[0340] Thresh1is expressed in the same unit asMl1.

[0341] Thresh2is expressed in the same unit asMl1.

[0342] NOTE: The definition of Event D1 also applies to CondEvent D1.

[0343] Figure 9 is a block diagram of an exemplary network entity that may be used in examples of the present disclosure. For example, a UE / base station (e.g. eNB, gNB) / network entity (e.g. AMF, SMF, NF) in the examples of Figures 1-8 may comprise an entity of Figure 9. The skilled person will appreciate that a network entity may be implemented, for example, 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.

[0344] The entity 900 comprises a processor (or controller) 901, a transmitter 903 and a receiver 905. The receiver 905 is configured for receiving one or more messages from one or more other network entities, for example as described above. The transmitter 903 is configured for transmitting one or more messages to one or more other network entities, for example as described above. The processor 901 is configured for performing one or more operations, for example according to the operations as described above.

[0345] Figure 10 illustrates a method according to the present disclosure. The method is performed by an entity (e.g. UE) for communication in (e.g. capable of communication in or configured to communicate in) an ATG network.

[0346] In step 1010, the entity calculates at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as a geodetic distance. Each of the at least one reference location may be located on the surface of the earth

[0347] In step 1020, the entity evaluates whether a condition is satisfied based on the at least one calculated distance.

[0348] In step 1030, the entity controls an operation relating to measurement based on a result of the evaluation.

[0349] In the present disclosure, the term "calculate" or similar expressions may be used interchangeably with "identify" or "determine." Accordingly, whenever the term "calculate" appears in this disclosure, it should not be construed in its strict dictionary sense but rather as encompassing broader interpretative meanings.

[0350] It will be appreciated that the present disclosure includes further examples whereby the method of Figure 10 is modified according to any one or more of the other examples describes herein or according to any one or more of the claims.

[0351] 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.

[0352] 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.

[0353] 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.

[0354] 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.

[0355] Abbreviations / Definitions

[0356] In the present disclosure, the following acronyms / definitions may be used.

[0357] 3GPP 3rdGeneration Partnership Project

[0358] 4G 4thGeneration

[0359] 5G 5thGeneration

[0360] 6G 6thGeneration

[0361] A2G Air to Ground

[0362] AMF Access and Mobility Management Function

[0363] ATG Air to Ground

[0364] BS Base Station

[0365] CDMA2000 family of standards based on Code Division Multiple Access

[0366] CE Control Element

[0367] EDGE Enhanced Data rates for GSM Evolution

[0368] eMTC Enhanced Machine Type Communication

[0369] eNB Base Station

[0370] E-UTRAN Evolved UMTS Terrestrial Radio Access Network

[0371] FDD Frequency Division Duplex

[0372] FL Flight Level

[0373] FR2 Frequency Range 2 (mmWave)

[0374] GEO Geostationary Orbit

[0375] GERAN GSM Edge Radio Access Network

[0376] gNB 5G Base Station

[0377] GNSS Global Navigation Satellite System

[0378] GPS Global Positioning System

[0379] GSM Global System for Mobile Communication

[0380] HAPS High Altitude Platform System

[0381] IMT International Mobile Telecommunications

[0382] IoT Internet of Things

[0383] LEO Lower Earth Orbit

[0384] LTE Long Term Evolution

[0385] LTE-M LTE Machine Type Communication

[0386] MAC Medium Access Control

[0387] MEO Medium Earth Orbit

[0388] NB Narrow Band

[0389] NF Network Function

[0390] NG Next Generation

[0391] NR New Radio

[0392] NTN Non Terrestrial Network

[0393] PRACH Physical Random Access Channel

[0394] RAN Radio Access Network

[0395] RAT Radio Access Technology

[0396] Rel Release

[0397] RF Radio Frequency

[0398] RRC Radio Resource Control

[0399] RRM Radio Resource Management

[0400] RSRP Reference Signal Received Power

[0401] RSRQ Reference Signal Received Quality

[0402] SIB System Information Block

[0403] SMF Session Management Function

[0404] SPCell Special Cell

[0405] SSB Synchronisation Signal Block

[0406] TN Terrestrial Network

[0407] TS Technical Specification

[0408] UE User Equipment

[0409] UMTS Universal Mobile Telecommunications System

[0410] UTRA Universal Terrestrial Radio Access

[0411] WLAN Wireless Local Area Network

Claims

1.A method performed by a network entity for communicating in an air-to-ground (ATG) network, the method comprising:identifying at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as a geodetic distance;determining whether a condition is satisfied based on the at least one identified distance; andbased on a result of the determination, controlling an operation relating to measurement;wherein each of the at least one reference location is located on the surface of the earth.2.The method of claim 1, wherein the identifying of the at least one distance relating to the network entity and the at least one reference location comprises:identifying a first distance, relating to the network entity and a first reference location, andidentifying a second distance, relating to the network entity and a second reference location; andwherein the condition is satisfied in case that:the first distance is greater than a first threshold and the second distance is less than a second threshold;the first distance is less than the first threshold;the second distance is greater than the second threshold;a first value equal to the first distance minus a hysteresis parameter is greater than the first threshold, and a second value equal to the second distance plus the hysteresis parameter is less than the second threshold;a third value equal to the first distance plus the hysteresis parameter is less than the first threshold; ora fourth value equal to the second distance minus the hysteresis parameter is greater than the second threshold.3.The method of claim 2, wherein the controlling of the operation relating to the measurement comprises:in case that the condition is satisfied, triggering a measurement report for a handover.4.The method of claim 1, wherein the identifying of the at least one distance relating to the network entity and the at least one reference location comprises:identifying a first distance relating to the network entity and a first reference location; andwherein the condition is satisfied in case that:the first distance is less than a first threshold.5.The method of claim 4, wherein the controlling of the operation relating to the measurement comprises:in case that the condition is satisfied, determining to access a cell and not performing intra-frequency measurements, measurements of NR inter-frequency cells of equal or lower priority, or measurements of inter-RAT frequency cells of lower priority, for a cell reselection; orin case that the condition is not satisfied, performing intra-frequency measurements, measurements of NR inter-frequency cells of equal or lower priority, or measurements of inter-RAT frequency cells of lower priority, for a cell reselection.6.The method of claim 1, wherein the identifying of the at least one distance relating to the network entity and the at least one reference location comprises:for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height of the network entity;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height of the reference location;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height of a base station;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height in the middle between the network entity and the reference location;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a respective height of the network entity and the reference location; orfor each reference location of the at least one reference location, identifying the geodesic distance between a location of the network entity and the reference location.7.The method of claim 6, wherein the location of the network entity is derived based on at least one of a global navigation satellite system (GNSS) and an inertial navigation system.8.The method of claim 1, further comprising:receiving, from a base station, information configuring the distance,wherein the received information configures one or more of: the distance as the geodetic distance, a height at which the distance is to be identified and the at least one reference location, andwherein the received information configures the distance as the geodetic distance or the Euclidean distance for a specific use case.9.A network entity for communicating in an air-to-ground (ATG) network, the network entity comprising at least one processor configured to:identify at least one distance relating to the network entity and at least one reference location, based on the at least one distance being configured as a geodetic distance;determine whether a condition is satisfied based on the at least one identified distance; andbased on a result of the determination, control an operation relating to measurement;wherein each of the at least one reference location is located on the surface of the earth.10.The network entity of claim 9, wherein the at least one processor is configured to identify the at least one distance relating to the network entity and the at least one reference location by:identifying a first distance, relating to the network entity and a first reference location, andidentifying a second distance, relating to the network entity and a second reference location; andwherein the condition is satisfied in case that:the first distance is greater than a first threshold and the second distance is less than a second threshold;the first distance is less than the first threshold;the second distance is greater than the second threshold;a first value equal to the first distance minus a hysteresis parameter is greater than the first threshold, and a second value equal to the second distance plus the hysteresis parameter is less than the second threshold;a third value equal to the first distance plus the hysteresis parameter is less than the first threshold; ora fourth value equal to the second distance minus the hysteresis parameter is greater than the second threshold.11.The network entity of claim 10, wherein the at least one processor is configured to control the operation relating to the measurement by:in case that the condition is satisfied, triggering a measurement report for a handover.12.The network entity of claim 9, wherein the at least one processor is configured to identify the at least one distance relating to the network entity and the at least one reference location by:identifying a first distance relating to the network entity and a first reference location; andwherein the condition is satisfied in case that:the first distance is less than a first threshold.13.The network entity of claim 12, wherein the at least one processor is configured to control the operation relating to the measurement by:in case that the condition is satisfied, determining to access a cell and not performing intra-frequency measurements, measurements of NR inter-frequency cells of equal or lower priority, or measurements of inter-RAT frequency cells of lower priority, for a cell reselection; orin case that the condition is not satisfied, performing intra-frequency measurements, measurements of NR inter-frequency cells of equal or lower priority, or measurements of inter-RAT frequency cells of lower priority, for a cell reselection.14.The network entity of claim 9, wherein the at least one processor is configured to identify the at least one distance relating to the network entity and the at least one reference location by:for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height of the network entity;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height of the reference location;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height of a base station;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a height in the middle between the network entity and the reference location;for each reference location of the at least one reference location, identifying the geodetic distance between a location of the network entity and the reference location at a respective height of the network entity and the reference location; orfor each reference location of the at least one reference location, identifying the geodesic distance between a location of the network entity and the reference location.15.The network entity of claim 14, wherein the location of the network entity is derived based on at least one of a global navigation satellite system (GNSS) and an inertial navigation system.

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