Performing downlink measurements in a non-terrestrial network

Abstract

According to an example aspect of the present disclosure, there is provided a method, comprising determining, by an apparatus, that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining, by the apparatus, a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities and performing, by the apparatus, downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

Description

PERFORMING DOWNLINK MEASUREMENTS IN A NON-TERRESTRIAL NETWORKFIELD

[0001] Various example embodiments relate in general to non-terrestrial networks and more specifically, to performing downlink measurements in such networks.BACKGROUND

[0002] Non-Terrestrial Network, NTN, refers to communication network infrastructure in which at least one of the network elements is positioned or operates outside of Earth's terrestrial surface. NTNs may utilize, for example, satellites, for providing wireless communication services. Said satellites usable in NTNs may comprise, for example, Low Earth Orbit, LEO, satellites which may reach speeds of up to 7600 m / s. 3rd Generation Partnership Project, 3GPP, develops standards for NTNs and there is a need to provide enhancements for performing downlink measurements in NTNs.SUMMARY

[0003] According to some aspects, there is provided the subject-matter of the independent claims. Some example embodiments are defined in the dependent claims.

[0004] The scope of protection sought for various example embodiments of the disclosure is set out by the independent claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various example embodiments of the disclosure.

[0005] According to an aspect of the present disclosure, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to determine that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multipledownlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determine a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities, and perform downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time. The apparatus may be a user equipment or a control device configured to control the functioning thereof, when installed therein.

[0006] According to an aspect of the present disclosure, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to determine that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determine a number of said multiple downlink measurement opportunities, determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities and perform downlink measurements in the non -terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time. The apparatus may be a user equipment or a control device configured to control the functioning thereof, when installed therein.

[0007] According to an aspect, there is provided a method comprising, determining that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities, and perform downlink measurements in the nonterrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time. The method may be performed by a user equipment or a control device configured to control the functioning thereof, when installed therein.

[0008] According to an aspect, there is provided a method comprising, determining that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a number of said multiple downlink measurement opportunities, determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities and performing downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time. The method may be performed by a user equipment or a control device configured to control the functioning thereof, when installed therein.

[0009] According to an aspect of the present disclosure, there is provided an apparatus comprising means for determining that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a nonterrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities, and perform downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time. The apparatus of the aspect may be a user equipment or a control device configured to control the functioning thereof, when installed therein.

[0010] According to an aspect of the present disclosure, there is provided an apparatus comprising means for determining that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a nonterrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a number of said multiple downlink measurement opportunities, determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowedfor performing downlink measurements on at least one of said multiple downlink measurement opportunities and performing downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time. The apparatus of the aspect may be a user equipment or a control device configured to control the functioning thereof, when installed therein.

[0011] According to an aspect of the present disclosure, there is provided a computer program comprising instructions which, when the program is executed by an apparatus, cause the apparatus to carry out determining that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a nonterrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities, and perform downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

[0012] According to an aspect of the present disclosure, there is provided a computer program comprising instructions which, when the program is executed by an apparatus, cause the apparatus to carry out determining that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a nonterrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a number of said multiple downlink measurement opportunities, determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities and performing downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

[0013] According to an aspect of the present disclosure, there is provided a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform determining that the apparatus is configured to perform measurements on multiple downlink measurementopportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities, and perform downlink measurements in the nonterrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

[0014] According to an aspect of the present disclosure, there is provided a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform determining that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception, determining a number of said multiple downlink measurement opportunities, determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities and performing downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 illustrates an example of a network scenario in accordance with at least some example embodiments;

[0016] FIG. 2 illustrates frame structures in accordance with at least some example embodiments;

[0017] FIG. 3 illustrates a flow chart in accordance with at least some example embodiments;

[0018] FIG. 4 illustrates an example apparatus capable of supporting at least some example embodiments;

[0019] FIG. 5 illustrates a first flow graph of a method in accordance with at least some example embodiments.

[0020] FIG. 6 illustrates a second flow graph of a method in accordance with at least some example embodiments.EXAMPLE EMBODIMENTS

[0021] Embodiments of the present disclosure provide enhancements for performing Downlink (DL) measurements in Non-Terrestrial Networks (NTNs). More specifically, relaxation is provided for performing measurements, e.g., for cell reselection or mobility, across multiple DL measurement opportunities in NTNs. To achieve said relaxation for performing DL measurements, a scaling factor may be exploited. The scaling factor may be used to extend a maximum time allowed for performing DL measurements on at least one of multiple DL measurement opportunities by a User Equipment (UE). The UE may thus select proper opportunities for measuring different DL measurement opportunities within the extended maximum time, thereby enabling power saving at the UE.

[0022] FIG. 1 illustrates an example of a network scenario in accordance with at least some example embodiments. More specifically, FIG.l illustrates NTN 100. Illustrated therein is UE 110, which may be equally called a user terminal, a user device or a terminal device. UE 110 may be, for example, a Machine-Type Communication (MTC) device, Internet of Things (loT) device, a 5G New Radio Reduced Capability (RedCap) device, an enhanced RedCap (eRedCap) device. In some embodiments, UE 110 may be a smartphone, a feature phone, a tablet computer, a laptop computer, a desktop computer or a smartwatch, or a vehicle, for example. UE 110 may be a half-duplex device, which cannot receive and transmit simultaneously.

[0023] UE 110 may be an NTN UE or a dual-capability UE. The dual-capability UE may be defined as a UE which is capable of both NTN communication as well as terrestrial network communication (e.g., communication in terrestrial cellular and / or non-cellular systems or networks). Examples of terrestrial cellular systems include Long Term Evolution, (LTE), fifth generation (5G), also known as New Radio (NR), and sixth generation (6G). Examples of terrestrial non-cellular systems include Wireless Local Area Network (WLAN) and Worldwide interoperability for Microwave Access (WiMAX).

[0024] UE 110 may be furnished with a satellite navigation capability, for example in the form of a satellite navigation receiver installed in UE 110. UE 110 may be configured to receive signals from a navigation satellite constellation, such as Global Positioning System (GPS) and / or the Galileo constellation. A satellite navigation capability may be used to determine the location and / or current time at UE 110. The satellite navigation satellite constellation may be distinct from an NTN satellite constellation that UE 110 may be configured to use for communication. Satellite links and NTN communications may be used at least to provide cellular communications to UEs on remote areas, disaster zones or over the sea.

[0025] In some embodiments, UE 110 may be, in particular, a Narrowband loT (NB-IoT) device. NB-IoT device may be defined as a UE capable of communicating with an NB-IoT network. The NB-IoT device is characterized by having a low power consumption, wide coverage and using a narrow frequency bandwidth. In some embodiments, the transmit power of the NB-IoT device may be equal to or smaller than 23 dBm. Additionally, or alternatively, said narrow frequency bandwidth of the NB-IoT device may be defined to be equal to or smaller than 180 kHz. In some embodiments, the NB-IoT device may belong to one of two NB-IoT categories: Category NB1 (having lower complexity) and Category NB2 (enabling support for higher data rates and additional features). Category NB1 and Category NB2 may be defined, respectively, in 3GPP Releases 13 & 14. Examples of NB-IoT devices may comprise a smart meter, an environmental sensor or a wearable device.

[0026] Service link 112 may connect UE 110 with NTN node 120. NTN node 120 may be referred to as a satellite, configured to perform non -terrestrial communications with UE 110 over service link 112. NTN node 120 may be in orbit 101 about the Earth, for example in Geostationary Earth Orbit, GEO, or Low-Earth Orbit, LEO. That is, NTN 100 may comprise satellites at LEO.

[0027] A GEO orbit may be defined as an orbit located at approximately 36000 km from Earth, above the equator. The orbit period of GEO satellites may be equivalent to one astronomical day. Therefore, GEO satellites may be static from the point of view of one user, or UE 110, on Earth. The GEO satellites have been around for decades and mostly used for low throughput applications. Recent technical developments have made the GEO deployments significantly attractive for new medium and high throughput applications using satellites.

[0028] LEO orbit may be defined as an orbit located at heights between 300 km and 1500 km above Earth. LEO satellites may be deployed in different orbit inclinations and orientationsaround Earth, and travel and significant speeds (approximately 7500 m / s at 600 km) and have a very high relative speed from an observer on Earth, such as UE 110.

[0029] Some embodiments may involve, in particular, NTN node 120 being a LEO satellite. In some such embodiments, the LEO satellites (or at least some of them) may have an altitude of 600 km or 1200 km with earth-fixed and / or earth-moving cells in the 1616-1626.5 MHz Mobile-Satellite Services (MSS) band.

[0030] In case of a regenerative architecture, lower layers may be implemented at the hardware located in non-terrestrial wireless network node 120, meaning that some central functions deployed by a Base Station (BS) may deployed at NTN node 120, such as scheduling, retransmissions and / or random access. A BS may be equally called an access node or an access point. In case of transparent architecture, hardware of NTN node 120 may act simply as a repeater or frequency converter, for a BS located on a ground station, such as BS 134, and the latency of the scheduling algorithms may be twice as high as in the case of regenerative architecture. In some example embodiments, NTN node 120 may be a transparent relay, meaning that NTN node 120 may act as an amplify-and-forward type of relay between UE 110 and a Non-Terrestrial Gateway (NTN-GW) 130 on the Earth’s surface.

[0031] In some example embodiments, NTN node 120 may be referred to as a BS. For example, in the context of LTE, NTN node 120 may be referred to as an eNB while NTN node 120 may be referred to as a gNB in the context of NR. In any case, example embodiments are not restricted to any particular wireless technology. Instead, example embodiments may be exploited in any cellular communication network wherein non-terrestrial communications are used, such as in 6G networks. NTN node 120 may be solar-powered or powered by heat from radioactive decay, for example. The satellite’s orbit 101 is, in part, schematically denoted in FIG. 1, as is its momentary orbital velocity vector 120v. Service link 112 may convey information in the DL, from NTN node 120 to UE 110, and in the Uplink (UL) from UE 110 to NTN node 120.

[0032] NTN node 120 may have feeder link 123 with the NTN-GW 130. As is the case with service link 112, feeder link 123 may convey information in both directions, UL and DL. Service link 112 and feeder link 123 may be wireless links, but they need not comply with the same wireless technology. However, in some embodiments, service link 112 and feeder link 123 may be based on the same wireless technology. NTN-GW 130 may comprise BS 134, or it may be arranged in connection with BS 134, wherefore UE 110 may access an NTN cellularsystem via NTN node 120 such that NTN node 120 may act as the bidirectional relay between UE 110 and NTN-GW 130.

[0033] One terrestrial BS 134 may control one or more cells and communicate with UE 110 over air interface 113. In some embodiments, BS 134 may have an interface with NTN- GW 130 or core network 140. NTN-GW 130 may be connected with further nodes via another gateway or core network 140, for example.

[0034] While NTN node 120 and UE 110 may be a mobile, NTN node 120 moving at a high speed, NTN-GW 130 may be a stationary node. When a constellation of NTN node 120 is employed, UE 110 may in principle be almost anywhere, or indeed anywhere, on the Earth’s surface. Compared to terrestrial cellular systems, NTN cellular systems may need enhanced timing corrections. Such enhancements are more central in NTN systems due to the long propagation distance, and delay, between UE 110 and NTN node 120 over service link 112, but also due to the fast movement of NTN node 120 which causes Doppler shifts. Furthermore, in transparent satellites, there is an additional time delay and frequency shift due to feeder link 123 between NTN-GW 130 and NTN node 120.

[0035] Said satellites usable in NTNs may comprise, for example, low Earth orbit (LEO) satellites which may reach speeds of up to 7600 m / s. This presents challenges for the operation of NTN 100 as UE 110 can only measure the radio signals transmitted by such LEO satellites for a limited amount of time before the satellite disappears beyond the horizon or the cell is switched away. Moreover, in LEO scenarios, the relative speed of the satellite imposes significant Doppler offsets which need to be post compensated by UE 110 in DL. Recently, adoption of Time Division Duplexing (TDD) for NB-IoT devices in NTNs has been suggested. Said problems need to be addressed in the implementation of said loT TDD for NB-IoT.

[0036] Compared to a purely terrestrial cellular communication systems, there are multiple challenges to be addressed in order to provide NTN coverage in a system natively designed to provide terrestrial coverage. One such challenge relates to the aforementioned high speeds of the LEO satellites. Due to said high speeds, UE 110 can only measure radio signals transmitted by such a LEO satellite for a limited amount of time before the satellite disappears on the horizon or the cell is switched away. Moreover, the high speed of the LEO satellites imposes significant doppler offsets which need to be post-compensated by UE 110 in DL. This fact needs to be taken into account, e.g., in cell reselection and mobility procedures used inNTNs. Namely, in the cell reselection requirements, the total time for the UE to complete the measurements may be scaled by a parameter called Ksateiiite.

[0037] In order to provide context for the embodiments to be discussed below which pertain adjustment of the parameter Ksateiiite, the definition and use of the parameter Ksateiiite is discussed the following. It is noted that the parameter Ksateiiite is defined, in general, according to 3GPP standards, namely at least 3GPP TS 36.133 and 36.306.

[0038] According to a conventional definition derived from 3GPP TS 36.133, the parameter Ksateiiite is a parameter for scaling measurements corresponding to multiple Non-Geostationary Orbit (NGSO) satellites (e.g., multiple LEO satellites). Non-geostationary satellites may be equivalently referred to as non-geosyncrhonous satellite. LEO satellites are an example of NGSO satellites.

[0039] If a geostationary orbit (GSO) satellite(s) is / are measured on the carrier or if there is only one NGSO satellite associated to cells the UE is required to monitor (or measure), Ksateiiite may be equal to 1. If multiple NGSO satellites are to be monitored (or measured), Ksateiiite may be equal to the number NGSO satellites to be measured. Typically, the maximum number of NGSO satellites which may be monitored by a single UE is 2 (and, thus, the value of Ksateiiite is limited to 2). The parameter Ksateiiite may be defined per frequency layer (i.e., per frequency band), as defined in 3GPP TS 36.306.

[0040] Embodiments of the present disclosure provide a new scaling factor to accommodate use of TDD. Namely, in connection with embodiments, if there are two or more NGSO satellites associated with the cells UE 110 is required to measure, the parameter Ksateiiite may be 1 or 2 depending on overlap of communication opportunities associated with said two or more NGSO satellites, as will be discussed in detail below.

[0041] The parameter Ksateiiite affects how measurements of intra-frequency NB-IoT cells (at least for UE category NB1) in normal coverage are carried out. UE 110 may be able to identify new intra-frequency cells and perform Narrowband Reference Signal Received Power (NRSRP) measurements of identified intra-frequency cells without an explicit intra-frequency neighbor list containing physical layer cell identities. UE 110 may be able to evaluate whether a newly detectable intra-frequency cell meets pre-defined reselection criteria defined in TS36.304 within Ksateiiite*Tdetect,NB_intra_Nc when Treselection= 0, where Tdetect,NB_intra_Nc is a (predefined) time reserved for detection of a new intra-frequency cell before evaluating it for (cell) reselection and Treselection is a (cell) reselection timer. An intra-frequency cell may beconsidered to be detectable according to any of NRSRP, NRSRP Es / Iot, NSCH RP and NSCH Es / Iot defined in Annex B.1.4 of 3GPP TS 36.133 for a corresponding band.

[0042] Moreover, UE 110 may measure NRSRP at least every Ksatellite *Tmeasure,NB_intra_NC at least for intra-frequency cells that are identified and measured according to the measurement rules. UE 110 may filter NRSRP measurements of each measured intra-frequency cell using at least 2 measurements. Within the set of measurements used for the filtering, at least two measurements may be spaced by at least Tmeasure,NBjntra-Nc / 2.

[0043] For an intra-frequency cell that has been already detected, but that has not been reselected to, the filtering may be such that UE 110 may be capable of evaluating that the intra-frequency cell has met reselection criterion defined in 3GPP TS 36.304 within KSateiiite*Tevaiuate,NB intra-Nc when Treseiection = 0, provided that the cell is at least XdB better ranked, where ‘X’ is specified in Table 4.6A.2.4-3 of 3GPP TS 36.133. When evaluating cells for reselection, the side conditions for NRSRP, NRSRP Es / Iot, NSCH RP and NSCH Es / Iot apply to both serving and non-serving NB-IoT intra-frequency cells.

[0044] The parameter Ksatellite may also have an effect on inter-frequency neighbor cell measurements, as defined in 3GPP TS 36.206 (namely, in Section 8.14A.6.4 thereof). Namely, UE 110 may be able to identify a new detectable inter-frequency cell within Tidentity _inter _NBI-NC,HI when pre-defined criteria for inter-frequency measurement, as defined in, is fulfilled, where Tidentify inter NBi-Nc,m is dependent on, among other parameters, on Ksatellite m(i.e., on the scaling factor Ksatellitedefined for frequency layer of index ni).

[0045] As indicated above, adoption of TDD in NB-IoT systems in NTNs has been suggested In at least some embodiments, the (LEO or NGSO) satellites may be assumed to employ TDD.

[0046] FIG. 2 illustrates frame structures in accordance with at least some example embodiments. Referring to FIG. 2, first TDD frame structure 210 applied by serving satellite 120, i.e., the serving NTN node of UE 110, comprises a simplex time slot, a 4 UL subframes and 4 DL subframes 212 to 218. DL subframes 212 to 218 may be referred to as DL measurement opportunities as well. TDD frame structures may be referred to as TDD periods, and said TDD periods may be periodically repeated.

[0047] The 4 UL subframes and 4 DL subframes 212 to 218 may be paired one-to-one to form 4 UL-DL subframe pairs (i.e., pairs ULI & DL1, UL2 & DL2, UL3 & DL3 and UL4 &DL4). That is, first TDD frame structure 210, which may be periodic, may comprise multiple DL measurement opportunities 212 to 218 and corresponding UL opportunities, and a sum of said multiple DL measurement opportunities 212 to 218 and corresponding UL opportunities may be less than a length of a TDD period, e.g., a length of TDD frame structure 210. Said multiple downlink opportunities 212 to 218 may be periodic subframes for DL reception during a TDD period.

[0048] The simplex time slot and each UL and DL subframe may be preceded by a (fixed or adjustable) guard period (depicted in FIG. 2 as black blocks). One UL-DL subframe pair, defining UL and DL opportunities, may be active at any given time. In other words, the active UL and DL subframes may always have the same index in TDD frame structure 210, i.e., within a TDD period. Each UL-DL subframe pair may define UL and DL opportunities (i.e., time windows during which UL and DL communication can be carried out). In the illustrated example, the simplex time slot has a duration of 20.32 ms, the UL subframes and DL subframes 212 to 218 have, each, a duration of 8.28 ms, and the total duration of TDD frame structure 210, i.e., a TDD period, is 90 ms. The guard period may be fixed or adjustable.

[0049] Second TDD frame structure 220 applied by neighbor satellite 122, i.e., the neighbor NTN node of UE 110, comprises similarly a simplex time slot, a 4 UL subframes and 4 DL subframes 222 to 228. However, there is a difference in propagation delay compared to serving satellite 120.

[0050] If UE 110 receives a scheduling grant in DL1 subframe, it will have to transmit in ULI subframe. Likewise, UL2, UL3 and UL4 are paired to different cells, or cell groups, and UEs in the area of coverage of the satellite. This means that, if UE 110 is transmitting on ULI, it is not expected to transmit in any of the other UL opportunities within the 90 ms TDD period and is only expected to receive information during DLL As is visible in FIG. 2, the separation between a DL opportunity and the paired UL opportunity is 3*8.28 ms + 3 guard periods + the simplex time slot and thus at least 45 ms.

[0051] More generally, the TDD frame structures usable in embodiments may comprise n DL slots and n UL slots, where the n DL slots and n UL slots are paired one-to-one to form n UL-DL slot pairs. Here, n is a positive integer. The n DL slots and n UL slots may be arranged, e.g., similar to the example of FIG. 2, that is, the n UL slots may precede the n DL slots. A (fixed or adjustable) guard period may precede each UL and DL subframe. Additionally, the TDD frame structures may comprise a simplex time slot (and its guard period) arranged in thebeginning of the TDD frame structure, similar to FIG. 2. Moreover, the specific time values indicated in FIG. 2 should be considered exemplary values. Thus, the durations of the different slots and the total duration of the TDD frame structure may differ from the ones shown in FIG.2, in some embodiments.

[0052] Therefore, the more cells UE 110 has to measure across different DL opportunities, the more time “ON” (i.e. measuring) will be used by UE 110, thereby spending the battery of UE 110. Embodiments of the present disclosure hence focus on addressing how to perform measurements when UE 110 has to measure several cells, or cell groups, across multiple DL opportunities. Adaptation of the measurement procedures and requirements at the side of UE 110 are enabled, when UE 110 is expected to measure across multiple DL opportunities.

[0053] In some embodiments, UE 110 may determine that it is configured to perform measurements on multiple DL measurement opportunities, such as at least two of DL opportunities 212 to 218 or 222 to 228, wherein each of said multiple DL measurement opportunities belongs to a different cell, or a different group of cells, of NTN 100. Said multiple DL measurement opportunities may be periodic subframes usable by UE 110 for DL reception. UE 110 may further determine a scaling factor, wherein the scaling factor extends a maximum time allowed for performing DL measurements on the at least one of said multiple DL measurement opportunities. After that, UE 110 may perform DL measurements in NTN 100 on the at least one of said multiple DL measurement opportunities within the extended maximum time.

[0054] The measurements may be performed to measure reference signal received power measurements on at least one of Narrowband Reference Signal (NRS), Narrowband Primary Synchronization Signal (NPSS) or Narrowband Secondary Synchronization Signal (NSSS). The measurements may be performed to enable mobility and connectivity of UE 110. Based on the measurements, UE 110 may perform at least one of cell reselection or a mobility event. The measurements may relate to, for example, cell detection for cell reselection, cell measurements for cell reselection or cell evaluation for cell reselection. The mobility event may comprise at least one of a handover of UE 110, RRC Re-establishment or RRC Release with redirection.

[0055] The maximum time may comprise at least one of a cell detection time, cell measurement time or cell evaluation time. The maximum time may be understood as a timerequirement for UE 110 to perform at least one action, in particular an action related to measuring DL.

[0056] For example, UE 110 may be configured to perform measurements across multiple DL opportunities (e.g., DLs 212 to 218 on the same satellite). The scaling factor may be thus exploited to avoid UE 110 to be “awake” performing measurements with high duty cycle. The scaling factor may be used to extend a maximum time to perform the measurements, thereby allowing UE 110 to select the proper opportunities to measure each of the different DL measurement opportunities. For example, DL1 might not be measured by UE 110 every 90 ms, but with a scaled (Monger) periodicity. That is, UE 110 may decide to measure DL1, e.g., during every second TDD period, if the allowed maximum time is twice as long as a default time for performing said measurements.

[0057] Said multiple DL measurement opportunities may be associated with one satellite, such as NTN node 120. Alternatively, the at least one of said multiple DL measurement opportunities may be associated with a first satellite, such as NTN node 120, and at least one other of said multiple DL measurement opportunities may be associated with at least one second satellite, such as NTN node 122, different from the first satellite.

[0058] In some embodiments, the scaling factor may be enabled by the network. That is, UE 110 may receive the scaling factor from a serving cell of UE 110 in NTN 100.

[0059] In some embodiments, UE 110 may determine a number of said multiple DL measurement opportunities, such as DL opportunities 212 to 218 and / or 222 to 228. UE 110 may further determine, when the number of said multiple DL measurement opportunities is above a threshold, to extend the maximum time allowed for performing DL measurements on the at least one of said multiple DL measurement opportunities. After that, UE 110 may perform DL measurements in NTN 100 on the at least one of said multiple DL measurement opportunities within the extended maximum time. The threshold may be, e.g., two, three, etc. For example, if the threshold is two, UE 110 may determine to extend the maximum time if there are more than two DL measurement opportunities. Thus, the scaling factor may be dependent on the number of different DL opportunities to be measured, wherein one DL opportunity may be linked to a cell, or a group of cells, to be measured.

[0060] In some embodiments, UE 110 may determine the number of said multiple DL measurement opportunities by determining how many of said DL measurement opportunities UE 110 expects to potentially comprise DL reference signal transmissions from at least onecell. Said determination may be based on satellite ephemeris, satellite footprint, timing information of transmissions, timing information of the applied DL-UL pair of a neighbor cell.

[0061] In some embodiments, UE 110 may determine to decrease a duty cycle associated with performing DL measurements on the at least one of said multiple DL measurement opportunities. For example, UE 110 may determine to decrease the duty cycle based on at least one of the scaling factor or when the number of said multiple DL measurement opportunities is above the threshold. The duty cycle may refer to an ON / OFF -ratio which may be reduced, because UE 110 may perform measurements less frequently on the selected DL measurement opportunities. Alternatively, or in addition, the duty cycle may refer to at least one of a number of measurements UE 110 performs or a number of samples UE 110 obtains within a TDD period.

[0062] In some embodiments, UE 110 may determine to increase a periodicity for performing DL measurements on the at least one of said multiple DL measurement opportunities. For example, UE 110 may determine to increase the periodicity based on at least one of the scaling factor or when the number of said multiple DL measurement opportunities is above the threshold.

[0063] In some embodiments, there may be prioritization for at least one of the DL measurement opportunities. For example, the DL measurement opportunities of the most relevant neighbor cells, and cells of the most relevant neighbor cells, may be prioritized. In such a case, the scaling factor may apply to the cells, or the group of cells, belonging to the other DL measurement opportunities than the DL measurement opportunities associated with the most relevant neighbor cells.

[0064] Prioritization may be enabled by using signalling, wherein NTN node 120 provides an indication about said prioritization to UE 110. For example, UE 110 may receive prioritization signalling from a serving cell of UE 110 in NTN 100 and determine, based on said prioritization signalling, the at least one of said multiple DL measurement opportunities for which the maximum time is allowed to be extended. In such a case, the at least one of said multiple DL measurement opportunities may belong to a cell, or a cell group, of a neighboring satellite 122 of FIG. 2.

[0065] Alternatively, or in addition, UE 110 may receive prioritization signalling from the serving cell of UE 110 in NTN 100 and determine, based on said prioritization signalling, at least one other of said multiple DL measurement opportunities for which the maximum timeis not allowed to be extended. In such a case, the at least one other of said multiple DL measurement opportunities may belong to a cell, or a cell group, of a neighboring satellite 122 of FIG. 2.

[0066] In some embodiments, said prioritization signalling may comprise an indication about at least one of the following:• prioritization in terms of DL opportunities to be measured;• prioritization in terms of physical cell Identity, ID, as long as UE 110 is capable of performing the mapping of the cell IDs to the different DL measurement opportunities;• prioritization in terms of an anchor carrier, when all cells are in the same band.

[0067] In some embodiments, the scaling may be dependent on a type of triggers for cell reselection or mobility event. For example, UE 110 may determine, based on a type of trigger for cell reselection or mobility event, at least one other of said multiple DL measurement opportunities for which extension of the maximum time for performing DL measurements is not allowed. The scaling may be dependent on the type of triggers at least based on one of the following:• for cell reselection initiated by (time-domain) proximity with a t-service event, i.e.serving cell will stop serving the area it is currently serving at time = t-service, the scaling factor might not be applicable. This ensures UE 110 will not scale or relax or extend the measurement time when there is an urgent need to reselect to a new cell. This trigger may be configured for (quasi) earth-fixed cells;• for connected mode mobility during Radio Resource Control (RRC) Re-establishment, the scaling factor might not be applicable; or• for distance-based cell reselection, the scaling factor might not be applicable if UE 110 is getting closer to a neighboring cell and / or UE 110 is getting further away from the serving cell. The distance-based trigger may include serving and neighbor cell reference locations and distance-thresholds and be applicable to earth-moving cells. This ensures UE 110 will not scale or relax or extend the measurement time when there is an urgent need to reselect to a new cell.

[0068] In some embodiments, UE 110 may extend the maximum time allowed for performing DL measurements on the at least one of said multiple DL measurement opportunities compared to a default time allowed for performing DL measurements. Said extending may refer, e.g., to extending the time requirements related to UE 110 performing DLmeasurements. Alternatively, or in addition, said extending may refer to a total time allowed for UE 110 to complete DL measurements. In some embodiments, said extending may refer to scaling and / or relaxing.

[0069] The default time may refer to a time allowed for performing DL measurements before UE 110 has determined that it is allowed to extend the maximum time for performing DL measurements on the at least one of said multiple DL measurement opportunities. For example, UE 110 may have performed DL measurements according to the default time before determining that it is allowed to extend the maximum time for performing DL measurements. The default time may be defined in a standard specification, such as a 3 GPP standard specification, and thus be pre-configured. In some embodiments, the default time may depend on whether Discontinuous Reception (DRX) is configured for UE 110. If DRX is configured for UE 110, the default time may depend on a DRX cycle configured for UE 110.

[0070] The default time may be, e.g., 4*90ms = 360ms (4 TDD periods), and it may be considered as a maximum time for performing DL measurements before UE 110 determines that it is allowed to extend the maximum time for performing DL measurements on the at least one of said multiple DL measurement opportunities. If UE 110 is allowed to extend the maximum time for performing, UE 110 may determine that the extended maximum time is 720ms (8 TDD periods). In such a case, UE 110 may perform measurements on a certain DL measurement opportunity during every second TDD period. For example, UE 110 may perform measurements on DL1 during 1st, 3rd, 5thand 7thTDD periods, and on DL2 during 2nd, 4th, 6thand 8thTDD periods.

[0071] UE 110 may thus extend the maximum time and perform a certain number of DL measurements within the extended maximum time, instead of the default time. However, it is noted that extending the maximum time is not limited to TDD periods. Instead, the extended maximum time may be any time period, such as 500ms.

[0072] FIG. 3 illustrates a flow chart in accordance with at least some example embodiments. The flow chart of FIG. 3 illustrates an example of operation of UE 110. As a starting point, UE 110 may be connected to NTN node 120.

[0073] At step 310, UE 110 may determine that it is configured with neighbor cell information. At step 320, UE 110 may determine whether there are neighbor cells (neighbors) mapped to different DL measurement opportunities. If not, UE 110 may, at step 330, proceed with non-scaled requirements. If yes, UE 110 may, at step 340, determine whether the numberof said multiple DL measurement opportunities is above the threshold. If not, UE 110 may proceed to step 330 and with non-scaled requirements. If yes, UE 110 may, at step 350, perform DL measurements in NTN 100 on the at least one of said multiple DL measurement opportunities within the extended maximum time. That is, UE 110 may apply the scaling factor to add relaxation to the time to detect, measure and / or evaluate neighbor cells.

[0074] In some embodiments, time to measure (Tmeasure) and time to detect (Tdetect) may be scaled using the scaling factor, e.g., when DRX is not configured, by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0075] In some embodiments, time to measure (Tmeasure) may be scaled using the scaling factor, e.g., when DRX is not configured, by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0076] In some embodiments, time to detect (Tdetect) may be scaled using the scaling factor, e.g., when DRX is not configured, by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0077] In some embodiments, time to evaluate (T evaluate) may be scaled using the scaling factor, e.g., when DRX is not configured, by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0078] In some embodiments, at least one of: time to measure (Tmeasure); time to detect (Tdetect); or time to evaluate (Tevaluate) may be scaled using the scaling factor, e.g., when DRX is not configured, by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0079] In some embodiments, when DRX is in use, the time to detect may be set to 6 DRX Cycles, whereas the time to measure may be set 5 DRX Cycles. For the largest DRX Cycles, the number of measurement opportunities may be sufficient for the UE to acquire the information of neighbor cells with no need for extending the minimum requirement. However, the main goal when DRX is configured is to save UE power, and for the smallest DRX Cycles,the UE will have to rely on almost every transmission opportunity to have sufficient number of samples to detect or measure the target cell. In this case, a scaling factor may be introduced only for the smallest DRX Cycle lengths (for example DRX Cycles length below 1.28 s).

[0080] In some embodiments, time to measure (Tmeasure) and time to detect (Tdetect) may be scaled using the scaling factor, e.g., when DRX is configured, for intra-frequency measurements by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0081] In some embodiments, time to measure (Tmeasure) may be scaled using the scaling factor, e.g., when DRX is configured, for intra-frequency measurements by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0082] In some embodiments, time to detect (Tdetect) may be scaled using the scaling factor, e.g., when DRX is configured, for intra-frequency measurements by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0083] In some embodiments, time to evaluate (T evaluate) may be scaled using the scaling factor, e.g., when DRX is configured, for intra-frequency measurements by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0084] In some embodiments, at least one of: time to measure (Tmeasure); time to detect (Tdetect); or time to evaluate (Tevaluate) may be scaled using the scaling factor, e.g., when DRX is configured, for intra-frequency measurements by a factor of [2], when UE 110 measures cells across 3 or more different patterns of DL opportunities. For example, a scaling factor may be referred to as “a factor”.

[0085] FIG. 4 illustrates an example apparatus capable of supporting at least some example embodiments. Illustrated is device 400, which may comprise, for example, UE 110 or NTN node 120, or a control device configured to control the functioning thereof, possibly when installed therein. Comprised in device 400 is processor 410, which may comprise, for example, a single- or multi-core processor wherein a single-core processor comprises one processor and a multi-core processor comprises more than one processor. Processor 410 may comprise, in general, a control device. Processor 410 may comprise more than one processor. Processor 410may be a control device. Processor 410 may comprise at least one application-specific integrated circuit, ASIC. Processor 410 may comprise at least one field-programmable gate array, FPGA. Processor 410 may be means for performing method steps in device 400. Processor 410 may be configured, at least in part by computer instructions, to perform actions.

[0086] A processor may comprise circuitry, or be constituted as circuitry or circuitries, the circuitry or circuitries being configured to perform phases of methods in accordance with example embodiments described herein. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and / or digital circuitry, and (b) combinations of hardware circuits and software, such as, as applicable: (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor s) or a portion of a microprocessor s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0087] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0088] Device 400 may comprise memory 420. Memory 420 may comprise randomaccess memory and / or permanent memory. Memory 420 may comprise at least one RAM chip. Memory 420 may comprise solid-state, magnetic, optical and / or holographic memory, for example. Memory 420 may be at least in part accessible to processor 410. Memory 420 may be at least in part comprised in processor 410. Memory 420 may be means for storing information. Memory 420 may comprise computer instructions that processor 410 is configured to execute. When computer instructions configured to cause processor 410 to perform certain actions are stored in memory 420, and device 400 overall is configured to run under the direction of processor 410 using computer instructions from memory 420, processor 410 and / or its at leastone processor may be considered to be configured to perform said certain actions. Memory 420 may be at least in part comprised in processor 410. Memory 420 may be at least in part external to device 400 but accessible to device 400.

[0089] Device 400 may comprise a transmitter 430. Device 400 may comprise a receiver 440. Transmitter 430 and receiver 440 may be configured to transmit and receive, respectively, information in accordance with at least one cellular or non-cellular standard. Transmitter 430 may comprise more than one transmitter. Receiver 440 may comprise more than one receiver. Transmitter 430 and / or receiver 440 may be configured to operate in accordance with Global System for Mobile communication, GSM, Wideband Code Division Multiple Access, WCDMA, Long Term Evolution, LTE, Narrowband Internet of Things (NB-IoT), and / or 5G / NR standards, for example.

[0090] Device 400 may comprise a Near-Field Communication, NFC, transceiver 450. NFC transceiver 450 may support at least one NFC technology, such as Bluetooth, Wibree or similar technologies.

[0091] Device 400 may comprise User Interface, UI, 460. UI 460 may comprise at least one of a display, a keyboard, a touchscreen, a vibrator arranged to signal to a user by causing device 400 to vibrate, a speaker and a microphone. A user may be able to operate device 400 via UI 460, for example to accept incoming telephone calls, to originate telephone calls or video calls, to browse the Internet, to manage digital files stored in memory 420 or on a cloud accessible via transmitter 430 and receiver 440, or via NFC transceiver 450, and / or to play games.

[0092] Device 400 may comprise or be arranged to accept a user identity module 470. User identity module 470 may comprise, for example, a Subscriber Identity Module, SIM, card installable in device 400. A user identity module 470 may comprise information identifying a subscription of a user of device 400. A user identity module 470 may comprise cryptographic information usable to verify the identity of a user of device 400 and / or to facilitate encryption of communicated information and billing of the user of device 400 for communication effected via device 400.

[0093] Processor 410 may be furnished with a transmitter arranged to output information from processor 410, via electrical leads internal to device 400, to other devices comprised in device 400. Such a transmitter may comprise a serial bus transmitter arranged to, for example, output information via at least one electrical lead to memory 420 for storage therein.Alternatively to a serial bus, the transmitter may comprise a parallel bus transmitter. Likewise processor 410 may comprise a receiver arranged to receive information in processor 410, via electrical leads internal to device 400, from other devices comprised in device 400. Such a receiver may comprise a serial bus receiver arranged to, for example, receive information via at least one electrical lead from receiver 440 for processing in processor 410. Alternatively to a serial bus, the receiver may comprise a parallel bus receiver.

[0094] Device 400 may comprise further devices not illustrated in FIG. 4. For example, where device 400 comprises a smartphone, it may comprise at least one digital camera. Some devices 400 may comprise a back-facing camera and a front-facing camera, wherein the back-facing camera may be intended for digital photography and the front-facing camera for video telephony. Device 400 may comprise a fingerprint sensor arranged to authenticate, at least in part, a user of device 400. In some example embodiments, device 400 lacks at least one device described above. For example, some devices 400 may lack a NFC transceiver 450 and / or user identity module 470.

[0095] Processor 410, memory 420, transmitter 430, receiver 440, NFC transceiver 450, UI 460 and / or user identity module 470 may be interconnected by electrical leads internal to device 400 in a multitude of different ways. For example, each of the aforementioned devices may be separately connected to a master bus internal to device 400, to allow for the devices to exchange information. However, as the skilled person will appreciate, this is only one example and depending on the example embodiment various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the example embodiments.

[0096] FIG. 5 is a first flow graph of a method in accordance with at least some example embodiments. The apparatus of the method may be UE 110 or by a control device configured to control the functioning thereof, when installed therein. That is, the phases of the illustrated first method may be performed by UE 110 or by a control device configured to control the functioning thereof, when installed therein.

[0097] The method may comprise, at step 510, determining, by an apparatus, that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus fordownlink reception. At step 520, the method may further comprise determining, by the apparatus, a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities. Finally, the method may comprise, at step 530, performing downlink measurements in the non -terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

[0098] FIG. 6 is a second flow graph of a method in accordance with at least some example embodiments. The phases of the illustrated first method may be performed by UE 110 or by a control device configured to control the functioning thereof, when installed therein.

[0099] The method may comprise, at step 610, determining, by an apparatus, that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception. The method may further comprise, at step 620, determining, by the apparatus a number of said multiple downlink measurement opportunities. The method may also comprise, at step 630, determining, by the apparatus, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities. Finally, the method may comprise, at step 640, performing, by the apparatus, downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

[0100] In some example embodiments,Example 1. An apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:- determine that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception;- determine a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities; and- perform downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.Example 2. The apparatus according to example 1, wherein said multiple downlink measurement opportunities are associated with one satellite.Example 3. The apparatus according to example 1, wherein the at least one of said multiple downlink measurement opportunities is associated with a first satellite and at least one other of said multiple downlink measurement opportunities is associated with at least one second satellite different from the first satellite.Example 4. The apparatus according to any of the preceding examples, wherein the nonterrestrial network comprises satellites at low earth orbit, LEO.Example 5. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine, based on the scaling factor, to decrease a duty cycle associated with performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 6. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:determine, based on the scaling factor, to increase a periodicity for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 7. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine to extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities based on a number of said multiple downlink measurement opportunities.Example 8. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine a number of said multiple downlink measurement opportunities; and - determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 9. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive prioritization signalling from a serving cell of the apparatus in the non-terrestrial network; and- determine, based on said prioritization signalling, the at least one of said multiple downlink measurement opportunities for which the maximum time is allowed to be extended.Example 10. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive prioritization signalling from a serving cell of the apparatus in the non-terrestrial network; and- determine, based on said prioritization signalling, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 11. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine, based on a type of trigger for cell reselection or mobility event, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 12. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive, from a serving cell of the apparatus in the non-terrestrial network, a configuration allowing the apparatus to extend the maximum time for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 13. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive the scaling factor from a serving cell of the apparatus in the non-terrestrial network.Example 14. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities compared to a default time allowed for performing downlink measurements.Example 15. The apparatus according to any of the preceding examples, wherein a periodic frame structure comprises said multiple downlink measurement opportunities and corresponding uplink opportunities, and a sum of said multiple downlink measurementopportunities and corresponding uplink opportunities is less than a length of a Time Division Duplexing, TDD, period.Example 16. The apparatus according to any of the preceding examples, wherein said multiple downlink opportunities are periodic subframes for downlink reception during a Time Division Duplexing, TDD, period.Example 17. The apparatus according to any of the preceding examples, wherein the maximum time comprises at least one of a cell detection time, cell measurement time or cell evaluation time.Example 18. The apparatus according to any of the preceding examples, wherein the apparatus is a narrowband internet of things, NB-IoT, device.Example 19. A method, comprising:- determining, by an apparatus, that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception; - determining, by the apparatus, a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities;- performing, by the apparatus, downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.Example 20. The method according to example 19, wherein said multiple downlink measurement opportunities are associated with one satellite.Example 21. The method according to example 19, wherein the at least one of said multiple downlink measurement opportunities is associated with a first satellite and at least one other of said multiple downlink measurement opportunities is associated with at least one second satellite different from the first satellite.Example 22. The method according to any of examples 18 to 21, wherein the non-terrestrial network comprises satellites at low earth orbit, LEO.Example 23. The method according to any of examples 18 to 22, further comprising:- determining, based on the scaling factor, to decrease a duty cycle associated with performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 24. The method according to any of examples 18 to 23, further comprising:- determining, based on the scaling factor, to increase a periodicity for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 25. The method according to any of examples 18 to 24, further comprising:- determining to extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities based on a number of said multiple downlink measurement opportunities.Example 26. The method according to any of examples 18 to 25, further comprising:- determining a number of said multiple downlink measurement opportunities; and - determining, when the number of said multiple downlink measurement opportunities is above a threshold, to extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 27. The method according to any of examples 18 to 26, further comprising:- receiving prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determining, based on said prioritization signalling, the at least one of said multiple downlink measurement opportunities for which the maximum time is allowed to be extended.Example 28. The method according to any of examples 18 to 27, further comprising:- receiving prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determining, based on said prioritization signalling, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 29. The method according to any of examples 18 to 29, further comprising:- determining, based on a type of trigger for cell reselection or mobility event, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 30. The method according to any of examples 18 to 29, further comprising:- receiving, from a serving cell of the apparatus in the non-terrestrial network, a configuration allowing the apparatus to extend the maximum time for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 31. The method according to any of examples 18 to 30, further comprising:receiving the scaling factor from a serving cell of the apparatus in the non -terrestrial network.Example 32. The method according to any of examples 18 to 31, further comprising:extending the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities compared to a default time allowed for performing downlink measurements.Example 33. The method according to any of examples 18 to 32, wherein a periodic frame structure comprises said multiple downlink measurement opportunities and corresponding uplink opportunities, and a sum of said multiple downlink measurement opportunities and corresponding uplink opportunities is less than a length of a Time Division Duplexing, TDD, period.Example 34. The method according to any of examples 18 to 33, wherein said multiple downlink opportunities are periodic subframes for downlink reception during a Time Division Duplexing, TDD, period.Example 35. The method according to any of examples 18 to 34, wherein the maximum time comprises at least one of a cell detection time, cell measurement time or cell evaluation time.Example 36. The method according to any of examples 18 to 35, wherein the apparatus is a narrowband internet of things, NB-IoT, device.

[0101] In some example embodiments,Example 1. An apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:- determine that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception;- determine a number of said multiple downlink measurement opportunities;- determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities; and - perform downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.Example 2. The apparatus according to example 1, wherein said multiple downlink measurement opportunities are associated with one satellite.Example 3. The apparatus according to example 1, wherein the at least one of said multiple downlink measurement opportunities is associated with a first satellite and at least one other of said multiple downlink measurement opportunities is associated with at least one second satellite different from the first satellite.Example 4. The apparatus according to any of the preceding examples, wherein the nonterrestrial network comprises satellites at low earth orbit, LEO.Example 5. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine, when the number of said multiple downlink measurement opportunities is above the threshold, to decrease a duty cycle associated with performing downlink measurements on the at least one of said multiple downlink measurement downlink opportunities.Example 6. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine, when the number of said multiple downlink measurement opportunities is above the threshold, to increase a periodicity for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 7. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:determine a scaling factor, wherein the scaling factor extends the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 8. The apparatus according to example 7, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive the scaling factor from a serving cell of the apparatus in the non-terrestrial network.Example 9. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive prioritization signalling from a serving cell of the apparatus in the non-terrestrial network; and- determine, based on said prioritization signalling, the at least one of said multiple downlink measurement opportunities for which the maximum time is allowed to be extended.Example 10. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive prioritization signalling from a serving cell of the apparatus in the non-terrestrial network; and- determine, based on said prioritization signalling, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 11. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine, based on a type of trigger for cell reselection or mobility event, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 12. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive, from a serving cell of the apparatus in the non-terrestrial network, a configuration allowing the apparatus to extend the maximum time for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 13. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities compared to a default time allowed for performing downlink measurements.Example 14. The apparatus according to any of the preceding examples, wherein a periodic frame structure comprises said multiple downlink measurement opportunities and corresponding uplink opportunities, and a sum of said multiple downlink measurement opportunities and corresponding uplink opportunities is less than a length of a Time Division Duplexing, TDD, period.Example 15. The apparatus according to any of the preceding examples, wherein said multiple downlink opportunities are periodic subframes for downlink reception during a Time Division Duplexing, TDD, period.Example 16. The apparatus according to any of the preceding claims, wherein the maximum time comprises at least one of a cell detection time, cell measurement time or cell evaluation time.Example 17. The apparatus according to any of the preceding examples, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine the number of said multiple downlink measurement opportunities by determining how many of said downlink measurement opportunities the apparatusexpects to potentially comprise downlink reference signal transmissions from at least one cell.Example 18. The apparatus according to any of the preceding examples, wherein the apparatus is a narrowband internet of things, NB-IoT, device.Example 19. A method, comprising:- determining, by an apparatus, that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception; - Determining, by the apparatus, a number of said multiple downlink measurement opportunities;- determining, by the apparatus, when the number of said multiple downlink measurement opportunities is above a threshold, to extend a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities; and- performing, by the apparatus, downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.Example 20. The method according to example 19, wherein said multiple downlink measurement opportunities are associated with one satellite.Example 21. The method according to example 19, wherein the at least one of said multiple downlink measurement opportunities is associated with a first satellite and at least one other of said multiple downlink measurement opportunities is associated with at least one second satellite different from the first satellite.Example 22. The method according to any of examples 19 to 21, wherein the non-terrestrial network comprises satellites at low earth orbit, LEO.Example 23. The method according to any of examples 19 to 22, further comprising:- determining, when the number of said multiple downlink measurement opportunities is above the threshold, to decrease a duty cycle associated with performing downlink measurements on the at least one of said multiple downlink measurement downlink opportunities.Example 24. The method according to any of examples 19 to 23, further comprising:- determining, when the number of said multiple downlink measurement opportunities is above the threshold, to increase a periodicity for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 25. The method according to any of examples 19 to 24, further comprising:- determining a scaling factor, wherein the scaling factor extends the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 26. The method according to example 25, further comprising:- receiving the scaling factor from a serving cell of the apparatus in the non -terrestrial network.Example 27. The method according to any of examples 19 to 26, further comprising:- receiving prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determining, based on said prioritization signalling, the at least one of said multiple downlink measurement opportunities for which the maximum time is allowed to be extended.Example 28. The method according to any of examples 19 to 27, further comprising:- receiving prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determining, based on said prioritization signalling, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 29. The method according to any of examples 19 to 28, further comprising:determining, based on a type of trigger for cell reselection or mobility event, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.Example 30. The method according to any of examples 19 to 29, further comprising:- receiving, from a serving cell of the apparatus in the non-terrestrial network, a configuration allowing the apparatus to extend the maximum time for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.Example 31. The method according to any of examples 19 to 30, further comprising:- extending the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities compared to a default time allowed for performing downlink measurements.Example 32. The method according to any of examples 19 to 31, wherein a periodic frame structure comprises said multiple downlink measurement opportunities and corresponding uplink opportunities, and a sum of said multiple downlink measurement opportunities and corresponding uplink opportunities is less than a length of a Time Division Duplexing, TDD, period.Example 33. The method according to any of examples 19 to 32, wherein said multiple downlink opportunities are periodic subframes for downlink reception during a Time Division Duplexing, TDD, period.Example 34. The method according to any of examples 19 to 33, wherein the maximum time comprises at least one of a cell detection time, cell measurement time or cell evaluation time.Example 35. The method according to any of examples 19 to 34, further comprising: determining the number of said multiple downlink measurement opportunities by determining how many of said downlink measurement opportunities the apparatus expects to potentially comprise downlink reference signal transmissions from at least one cell.Example 36. The method according to any of examples 19 to 35, wherein the apparatus is a narrowband internet of things, NB-IoT, device.

[0102] It is to be understood that the example embodiments disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular example embodiments only and is not intended to be limiting.

[0103] Reference throughout this specification to one example embodiment or an example embodiment means that a particular feature, structure, or characteristic described in connection with the example embodiment is included in at least one example embodiment. Thus, appearances of the phrases “in one example embodiment” or “in an example embodiment” in various places throughout this specification are not necessarily all referring to the same example embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed.

[0104] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various example embodiments and examples may be referred to herein along with alternatives for the various components thereof. It is understood that such example embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations.

[0105] In an example embodiment, an apparatus, such as, for example, UE 110 or NTN node 120, may comprise means for carrying out the example embodiments described above and any combination thereof.

[0106] In an example embodiment, a computer program may be configured to cause a method in accordance with the example embodiments described above and any combination thereof. In an example embodiment, a computer program product, embodied on a non-transitorycomputer readable medium, may be configured to control a processor to perform a process comprising the example embodiments described above and any combination thereof.

[0107] In an example embodiment, an apparatus, such as, for example, UE 110 or NTN node 120, may comprise at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform the example embodiments described above and any combination thereof.

[0108] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments. In the preceding description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of example embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the disclosure can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

[0109] While the forgoing examples are illustrative of the principles of the example embodiments in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the disclosure. Accordingly, it is not intended that the disclosure be limited, except as by the claims set forth below.

[0110] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", that is, a singular form, throughout this document does not exclude a plurality.INDUSTRIAL APPLICABILITY

[0111] At least some example embodiments find industrial application in cellular communication networks, for example in 3 GPP networks.REFERENCE SIGNS LIST

Claims

CLAIMS:

1. An apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:- determine that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception;- determine a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities; and- perform downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

2. The apparatus according to claim 1, wherein said multiple downlink measurement opportunities are associated with one satellite.

3. The apparatus according to claim 1, wherein the at least one of said multiple downlink measurement opportunities is associated with a first satellite and at least one other of said multiple downlink measurement opportunities is associated with at least one second satellite different from the first satellite.

4. The apparatus according to any of the preceding claims, wherein the non-terrestrial network comprises satellites at low earth orbit, LEO.

5. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:determine, based on the scaling factor, to decrease a duty cycle associated with performing downlink measurements on the at least one of said multiple downlink measurement opportunities.

6. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine, based on the scaling factor, to increase a periodicity for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.

7. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine to extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities based on a number of said multiple downlink measurement opportunities.

8. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine a number of said multiple downlink measurement opportunities; and - determine, when the number of said multiple downlink measurement opportunities is above a threshold, to extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.

9. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determine, based on said prioritization signalling, the at least one of said multiple downlink measurement opportunities for which the maximum time is allowed to be extended.

10. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determine, based on said prioritization signalling, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.

11. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- determine, based on a type of trigger for cell reselection or mobility event, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.

12. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive, from a serving cell of the apparatus in the non-terrestrial network, a configuration allowing the apparatus to extend the maximum time for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.

13. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:- receive the scaling factor from a serving cell of the apparatus in the non-terrestrial network.

14. The apparatus according to any of the preceding claims, wherein the at least one processor and the at least one memory are further configured to cause the apparatus at least to:extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities compared to a default time allowed for performing downlink measurements.

15. The apparatus according to any of the preceding claims, wherein a periodic frame structure comprises said multiple downlink measurement opportunities and corresponding uplink opportunities, and a sum of said multiple downlink measurement opportunities and corresponding uplink opportunities is less than a length of a Time Division Duplexing, TDD, period.

16. The apparatus according to any of the preceding claims, wherein said multiple downlink opportunities are periodic subframes for downlink reception during a Time Division Duplexing, TDD, period.

17. The apparatus according to any of the preceding claims, wherein the maximum time comprises at least one of a cell detection time, cell measurement time or cell evaluation time.

18. The apparatus according to any of the preceding claims, wherein the apparatus is a narrowband internet of things, NB-IoT, device.

19. A method, comprising:- determining, by an apparatus, that the apparatus is configured to perform measurements on multiple downlink measurement opportunities, wherein each of said multiple downlink measurement opportunities belongs to a different cell, or to a different group of cells, of a non-terrestrial network, and said multiple downlink measurement opportunities are periodic subframes usable by the apparatus for downlink reception;- determining, by the apparatus, a scaling factor, wherein the scaling factor extends a maximum time allowed for performing downlink measurements on at least one of said multiple downlink measurement opportunities; and- performing, by the apparatus, downlink measurements in the non-terrestrial network on the at least one of said multiple downlink measurement opportunities within the extended maximum time.

20. The method according to claim 19, wherein said multiple downlink measurement opportunities are associated with one satellite.

21. The method according to claim 19, wherein the at least one of said multiple downlink measurement opportunities is associated with a first satellite and at least one other of said multiple downlink measurement opportunities is associated with at least one second satellite different from the first satellite.

22. The method according to any of claims 19 to 21, wherein the non-terrestrial network comprises satellites at low earth orbit, LEO.

23. The method according to any of claims 19 to 22, further comprising:- determining, based on the scaling factor, to decrease a duty cycle associated with performing downlink measurements on the at least one of said multiple downlink measurement opportunities.

24. The method according to any of claims 19 to 23, further comprising:- determining, based on the scaling factor, to increase a periodicity for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.

25. The method according to any of claims 19 to 24, further comprising:- determining to extend the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities based on a number of said multiple downlink measurement opportunities.

26. The method according to any of claims 19 to 25, further comprising:- determining a number of said multiple downlink measurement opportunities; and - determining, when the number of said multiple downlink measurement opportunities is above a threshold, to extend the maximum time allowed for performing downlinkmeasurements on the at least one of said multiple downlink measurement opportunities.

27. The method according to any of claims 19 to 26, further comprising:- receiving prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determining, based on said prioritization signalling, the at least one of said multiple downlink measurement opportunities for which the maximum time is allowed to be extended.

28. The method according to any of claims 19 to 27, further comprising:- receiving prioritization signalling from a serving cell of the apparatus in the nonterrestrial network; and- determining, based on said prioritization signalling, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.

29. The method according to any of claims 19 to 28, further comprising:- determining, based on a type of trigger for cell reselection or mobility event, at least one other of said multiple downlink measurement opportunities for which extension of the maximum time for performing downlink measurements is not allowed.

30. The method according to any of claims 19 to 29, further comprising:- receiving, from a serving cell of the apparatus in the non-terrestrial network, a configuration allowing the apparatus to extend the maximum time for performing downlink measurements on the at least one of said multiple downlink measurement opportunities.

31. The method according to any of claims 19 to 30, further comprising:- receiving the scaling factor from a serving cell of the apparatus in the non -terrestrial network.

32. The method according to any of claims 19 to 31, further comprising:- extending the maximum time allowed for performing downlink measurements on the at least one of said multiple downlink measurement opportunities compared to a default time allowed for performing downlink measurements.

33. The method according to any of claims 19 to 32, wherein a periodic frame structure comprises said multiple downlink measurement opportunities and corresponding uplink opportunities, and a sum of said multiple downlink measurement opportunities and corresponding uplink opportunities is less than a length of a Time Division Duplexing, TDD, period.

34. The method according to any of claims 19 to 33, wherein said multiple downlink opportunities are periodic subframes for downlink reception during a Time Division Duplexing, TDD, period.

35. The method according to any of claims 19 to 34, wherein the maximum time comprises at least one of a cell detection time, cell measurement time or cell evaluation time.

36. The method according to any claims 19 to 35, wherein the apparatus is a narrowband internet of things, NB-IoT, device.

37. A computer program comprising instructions which, when the program is executed by an apparatus, cause the apparatus to carry out the method according to any of claims 19 to 36.

38. a non-transitory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause an apparatus to at least perform the method according to any of claims 19 to 36.

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