Aerial user equipment, radio access network node, and methods therefor

Abstract

This Aerial User Equipment (UE) receives system information via a broadcast in a first cell. If system information does not contain first information indicating whether or not the first cell is barred for Aerial UEs, the Aerial UE does not handle the first cell as a barred cell in cell selection or cell reselection. The foregoing may, for example, contribute to solving a problem related to realizing a mechanism for enabling Aerial UEs to respect a no-transmit zone (NTZ).

Description

Aerial User Equipment, Radio Access Network Node, and Methods Thereof

[0001] The present disclosure relates to wireless communication systems, and more particularly to aerial User Equipments (UEs).

[0002] The 3rd Generation Partnership Project (3GPP®) Release 15 and later releases support aerial User Equipment (UE) communications. In 3GPP Releases 15-17, an Evolved Universal Terrestrial Radio Access Network (E-UTRAN)-based mechanism for providing Long Term Evolution (LTE) connectivity to aerial-capable UEs is supported through the following functionalities: subscription-based aerial UE identification and authorization; height reporting based on the event that the UE's altitude exceeds a network-configured reference altitude threshold; interference detection based on measurement reports that are triggered when a configured number of cells (i.e., greater than one) simultaneously meet the trigger criteria; signaling of flight path information from the UE to the E-UTRAN; and location information reporting, including the UE's horizontal and vertical velocity.

[0003] 3GPP Release 18 is expected to support similar functions to those described above to provide New Radio (NR) communications to aerial UEs (see, for example, Non-Patent Documents 1-6).

[0004] The European Conference of Postal and Telecommunications Administrations (CEPT) Electronic Communications Committee (ECC) Decision (22)07, dated November 8, 2022, specifies technical requirements for out-of-band (OOB) emission limits specific to aerial UEs and no-transmit zones (NTZs) specific to aerial UEs (see Non-Patent Document 7). NTZs are geographical areas where aerial UEs are not permitted to operate in certain frequency bands due to coexistence with other wireless systems and services, such as digital terrestrial television (DTT) receivers, Radio Astronomy Service (RAS) sites, and radar sites. ECC Decision (22)07 requires that the no-transmit zones (NTZs) described in the Decision be defined and implemented at the national level and coordinated with neighboring countries as necessary.

[0005] The coexistence conditions stated in ECC Decision (22)07 are listed below. These coexistence conditions are formulated under the assumption that a mechanism exists to distinguish between aerial UE and conventional UE, and that this mechanism cannot be changed by end users. A mechanism is required to ensure that aerial UE respects NTZs. In ECC Decision (22)07, the term aerial UE means UE that supports Unmanned Aircraft Systems (UAS) functions and services and requires an aerial subscription. Aerial UE can be installed on unmanned aerial vehicles (e.g., drones) or manned aircraft (e.g., helicopters, flying taxis).

[0006] For example, to avoid interference with DTT receivers, NTZs are required for aerial UE operating in the 703-733 MHz band at heights up to 30 m above the ground. In other words, aerial UE operating in the 703-733 MHz band must not transmit at heights less than 30 m above the ground.

[0007] For example, around RAS sites operating in the 1400-1427 MHz band, nationally determined NTZs are required for aerial UE operating in the 703-718 MHz frequency band, as appropriate.

[0008] For example, around RAS sites operating in the 1660-1670 MHz band, nationally determined NTZs are required for aerial UE operating in the 832-837 MHz frequency band, as appropriate.

[0009] For example, around RAS sites operating in the 2690-2700 MHz band, nationally determined NTZs are required for aerial UE operating in the 2500-2570 MHz or 2570-2620 MHz frequency bands, as appropriate.

[0010] For example, around radars operating in the 2700-2900 MHz band, nationally determined NTZs may be required for aerial UE operating in the 2500-2570 MHz or 2570-2620 MHz frequency bands.

[0011] Non-Patent Document 6 includes the following description of mechanisms for addressing the NTZ requirements set in "ECC Decision (22)07" of CEPT ECC: If the NTZ is understood very strictly, an aerial UE (e.g., an Uncrewed Aerial Vehicle (UAV)) should not initially access a cell within the NTZ. In this case, the aerial UE cannot even camp on this cell. In contrast, in a less strict scenario, the aerial UE can access the cell but be steered to another cell for further transmission. A flying aerial UE can see several cells, and even if the aerial UE itself is within or near the NTZ, it may be able to receive service from a distant cell. Another aspect that should be considered is the potential for interference to neighboring cells. If an aerial UE is connected to another cell while within the NTZ, the aerial UE may cause unwanted interference. This also applies when the aerial UE is near the NTZ.

[0012] Two types of mechanisms can be considered for aerial UEs to respect NTZ: one with cell-level granularity and the other with finer granularity, where Radio Access Network (RAN) nodes impose cell-level measures to prevent aerial UEs from accessing NTZ-affected cells.

[0013] At a finer granularity, an aerial UE in Radio Resource Control (RRC)_CONNECTED mode notifies the RAN node when the UE enters or leaves the NTZ. Signaling can be defined to notify the RAN node when an aerial UE in RRC_CONNECTED mode enters the NTZ, allowing the network to make preparations to maintain connectivity with the aerial UE (e.g., switch to another frequency band or carrier allowed within the NTZ). Conversely, knowing when an aerial UE leaves the NTZ allows the network to restore the previous communication mode with the aerial UE. This may be required, for example, to monitor interference caused by aerial UEs near the NTZ.

[0014] The first mechanism (cell level) has several advantages. First, it is applicable to UEs in both connected and idle modes. Second, it requires less work from the 3GPP Technical Specification Group (TSG) Radio Access Network (RAN) Working Group #2 (WG2) (RAN2). Specifically, only one bit in the system information broadcast by the network is required to prohibit access of aerial UEs to cells affected by NTZ.

[0015] Non-Patent Document 6 proposes to define signaling that enables cells affected by NTZ to prohibit access of aerial UEs.

[0016] 3GPP TS 23.256 V18.1.0 (2023-06), "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Support of Uncrewed Aerial Systems (UAS) connectivity, identification and tracking; Stage 2 (Release 18)", June 2023 InterDigital, "Report from Session on NES, UAV, Rel-15-17 UP, Rel-17 Small Data, IIoT / URLLC, and RACH partitioning", R2-2306543, 3GPP TSG-RAN WG2 Meeting #122, Incheon, Korea, May 22-26, 2023 Nokia, Nokia Shanghai Bell, "Stage-2 Text Proposal for Rel-18 UAVs", R2-2305886, 3GPP TSG-RAN WG2 Meeting #122, Incheon, Korea, May 22-26, 2023 Ericsson, "UAV flight path reporting", R2-2305544, 3GPP TSG-RAN WG2 Meeting #122, Incheon, Korea, May 22-26, 2023 Nokia, Nokia Shanghai Bell, "Further Details on Flight Path Plan (FPP)", R2-2305887, 3GPP TSG-RAN WG2 Meeting #122, Incheon, Korea, May 22-26, 2023 Ericsson, "No-transmit zones for UAVs", RP-231203, 3GPP TSG RAN Meeting #100, Taipei, 12-14 June,2023European Conference of Postal and Telecommunications Administrations (CEPT), "Harmonised technical conditions for the usage of aerial UE for communications based on LTE and 5G NR in the bands 703-733 MHz, 832-862 MHz, 880-915 MHz, 1710-1785 MHz, 1920-1980 MHz, 2500-2570 MHz and 2570-2620 MHz harmonized for MFCN", ECC / DEC / (22)07, November 18, 2022,

[0017] The inventors have investigated mechanisms for addressing the NTZ requirements set in CEPT ECC's "ECC Decision (22)07" and have found various challenges. Some of these challenges relate to improving cell selection or cell reselection to enable aerial UEs to respect NTZ. Non-Patent Document 6 describes that only one bit in the system information broadcast by the network is required to prohibit aerial UEs from accessing cells affected by NTZ. However, Non-Patent Document 6 does not disclose any further details, and the details of the procedures and signaling to enable aerial UEs to respect NTZ are still not sufficiently clear.

[0018] One of the objectives to be achieved by the embodiments disclosed in this specification is to provide an apparatus, a method, and a program that contribute to solving at least one of the multiple objectives related to realizing a mechanism for enabling aerial UEs to respect NTZ, including the above-mentioned problem. It should be noted that this objective is only one of the multiple objectives to be achieved by the multiple embodiments disclosed in this specification. Other objectives or objectives and novel features will be apparent from the description of this specification or the accompanying drawings.

[0019] In a first aspect, an aerial UE is configured to receive system information via broadcast in a first cell. The aerial UE is configured to treat the first cell as a prohibited cell in cell selection or cell reselection if the system information includes first information indicating whether the first cell is barred for aerial UEs and the first information indicates that the first cell is barred for aerial UEs. The aerial UE is configured not to treat the first cell as a prohibited cell in cell selection or cell reselection if the system information includes the first information and the first information indicates that the first cell is not barred for aerial UEs. Furthermore, the aerial UE is configured not to treat the first cell as a prohibited cell in cell selection or cell reselection if the system information does not include the first information.

[0020] In a second aspect, a method performed by an aerial UE includes the following steps: (a) receiving system information via broadcast in a first cell; (b) treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes first information indicating whether the first cell is prohibited for aerial UEs and the first information indicates that the first cell is prohibited for aerial UEs; (c) not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes the first information and the first information indicates that the first cell is not prohibited for aerial UEs; and (d) not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information does not include the first information.

[0021] In a third aspect, an aerial UE is configured to receive first information via broadcast in a first cell, the first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

[0022] In a fourth aspect, a method performed by an aerial UE includes receiving first information via broadcast in a first cell, the first information indicating that the first cell belongs to or includes an NTZ for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

[0023] In a fifth aspect, a RAN node is configured to broadcast first information in a first cell, the first information indicating that the first cell belongs to or includes a NTZ for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

[0024] In a sixth aspect, a method performed by a RAN node includes broadcasting first information in a first cell, the first information indicating that the first cell belongs to or includes a NTZ for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but not uplink communication services to aerial UEs.

[0025] In a seventh aspect, the aerial UE is configured to receive, at the first cell, an excluded cell list specific to the aerial UE, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UE.

[0026] In an eighth aspect, a method performed by an aerial UE includes receiving, at a first cell, an excluded cell list specific to the aerial UE, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UE.

[0027] In a ninth aspect, the RAN node is configured to transmit, in the first cell, an excluded cell list specific to the aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UEs.

[0028] In a tenth aspect, a method performed by a RAN node includes transmitting, in a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells that are to be excluded as candidate cells for cell reselection by the aerial UEs.

[0029] In an eleventh aspect, an aerial UE is configured to receive, at a first cell, a neighbor cell list specific to the aerial UE, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a NTZ for the aerial UE, a cell that is not permitted for uplink transmission to the aerial UE, or a cell that provides downlink communication services to the aerial UE but not uplink communication services to the aerial UE.

[0030] In a twelfth aspect, a method performed by an aerial UE includes receiving, at a first cell, a neighbor cell list specific to the aerial UE, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes an NTZ for the aerial UE, a cell that is not permitted for uplink transmissions to the aerial UE, or a cell that provides downlink communication services to the aerial UE but not uplink communication services to the aerial UE.

[0031] In a thirteenth aspect, the RAN node is configured to transmit, in a first cell, a neighbor cell list specific to the aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a NTZ for the aerial UEs, a cell from which uplink transmissions are not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.

[0032] In a fourteenth aspect, a method performed by a RAN node includes transmitting, in a first cell, a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes an NTZ for the aerial UE, a cell that is not permitted for uplink transmissions to the aerial UE, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.

[0033] In a fifteenth aspect, a RAN node is configured to send first information to a neighboring RAN node indicating whether a first cell of the RAN node at least partially overlaps with a NTZ for aerial UEs, and to receive second information from the neighboring RAN node indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ.

[0034] In a sixteenth aspect, a method performed by a RAN node includes transmitting first information to a neighboring RAN node indicating whether a first cell of the RAN node at least partially overlaps with a NTZ for aerial UEs, and receiving second information from the neighboring RAN node indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ.

[0035] In a seventeenth aspect, a central unit of a RAN node is configured to send, to a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0036] In an eighteenth aspect, a method performed by a central unit of a RAN node includes transmitting, to a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0037] In a nineteenth aspect, a distributed unit of a RAN node is configured to receive, from a central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0038] In a twentieth aspect, a method performed by a distributed unit of a RAN node includes receiving first information from a central unit of the RAN node indicating whether a first cell provided by the distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0039] In a twenty-first aspect, a central unit of a RAN node is configured to receive, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0040] In a twenty-second aspect, a method performed by a central unit of a RAN node includes receiving, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0041] In a twenty-third aspect, a distributed unit of a RAN node is configured to transmit first information to a central unit of the RAN node, the first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0042] In a twenty-fourth aspect, a method performed by a distributed unit of a RAN node includes transmitting, to a central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a NTZ for aerial UEs.

[0043] In a twenty-fifth aspect, a program includes a group of instructions (software code) that, when loaded into a computer, causes the computer to perform a method according to any of the above aspects.

[0044] According to the above-described aspects, it is possible to provide an apparatus, a method, and a program that contribute to solving at least one of a number of problems related to implementing a mechanism for enabling aerial UEs to respect NTZ.

[0045]

[0014] Figure 1 illustrates an example configuration of a wireless communication system according to one or more embodiments.

[0015] Figure 2 illustrates an example sequence diagram of an aerial UE and a RAN node according to one or more embodiments.

[0016] Figure 3 illustrates an example flow chart of an aerial UE according to one or more embodiments.

[0017] Figure 4 illustrates an example sequence diagram of an aerial UE and a RAN node according to one or more embodiments.

[0018] Figure 5 illustrates an example sequence diagram of an aerial UE and a RAN node according to one or more embodiments.

[0019] Figure 6 illustrates an example sequence diagram of an aerial UE and a RAN node according to one or more embodiments.

[0020] Figure 7 illustrates an example format of a System Information Block type 3 (SIB3) information element according to one or more embodiments.

[0021] Figure 8 illustrates an example format of a SIB type 4 (SIB4) information element according to one or more embodiments.

[0022] Figure 9 illustrates an example sequence diagram of an aerial UE and a RAN node according to one or more embodiments.

[0023] Figure 10 illustrates an example format of a SIB3 information element according to one or more embodiments.

[0024] Figure 11 illustrates an example format of a SIB4 information element according to one or more embodiments.

[0025] Figure 12 illustrates an example sequence diagram of signaling between RAN nodes according to one or more embodiments. 1 is a flowchart illustrating an example of the operation of a RAN node, in accordance with one or more embodiments; 2 is a flowchart illustrating an example of the operation of a RAN node, in accordance with one or more embodiments; 3 is a diagram illustrating an example of the format of a Served Cell Information NR information element, in accordance with one or more embodiments; 4 is a diagram illustrating an example of the format of a Neighbor Information NR information element, in accordance with one or more embodiments; 5 is a diagram illustrating an example of the configuration of a RAN node, in accordance with one or more embodiments; 6 is a sequence diagram illustrating example signaling between a central unit and a distributed unit, in accordance with one or more embodiments;FIG. 1 is a sequence diagram illustrating example signaling between a central unit and a distributed unit, according to one or more embodiments; FIG. 2 is a sequence diagram illustrating example signaling between a central unit and a distributed unit, according to one or more embodiments; FIG. 3 is a sequence diagram illustrating example operation of an aerial UE and a RAN node, according to one or more embodiments; FIG. 4 is a sequence diagram illustrating example operation of an aerial UE and a RAN node, according to one or more embodiments; FIG. 5 is a flowchart illustrating example operation of an aerial UE, according to one or more embodiments; FIG. 6 is a flowchart illustrating example operation of an aerial UE, according to one or more embodiments; FIG. 7 is a sequence diagram illustrating example operation of an aerial UE and a RAN node, according to one or more embodiments; FIG. 8 is a block diagram illustrating an example configuration of an aerial UE, according to one or more embodiments; FIG. 9 is a block diagram illustrating an example configuration of a RAN node, according to one or more embodiments;

[0046] Hereinafter, specific embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary.

[0047] The multiple embodiments described below may be used independently, or two or more embodiments may be combined as appropriate. These multiple embodiments may have different novel features. Therefore, these multiple embodiments may contribute to achieving different objectives or solving different problems, and may contribute to achieving different effects.

[0048] Each drawing is merely an example for describing one or more embodiments. Each drawing may not relate to only one particular embodiment, but may also relate to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0049] The following embodiments are described primarily for the 3GPP 5th generation mobile communication system (5G system), but may also be applied to other wireless communication systems that support wireless terminals similar to 3GPP aerial UEs.

[0050] As used herein, depending on the context, "if" may be interpreted to mean "when," "while," "at or around the time," "after," "upon," "in response to determining," "in accordance with a determination," or "in response to detecting." These expressions may be interpreted to have the same meaning, depending on the context.

[0051] First, the configurations and operations of several network elements common to several embodiments will be described. Fig. 1 shows an example configuration of a wireless communication system related to several embodiments. Each of the elements shown in Fig. 1 is a network function and provides an interface defined by, for example, 3GPP. Each element (network function) shown in Fig. 1 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform.

[0052] The wireless communication system shown in Fig. 1 includes an aerial UE 1 and multiple RAN nodes 2 (specifically, RAN nodes 2A to 2G). Hereinafter, when describing matters common to the multiple RAN nodes 2A to 2G, reference will be made to the RAN node 2 unless otherwise specified. The RAN node 2 may be, for example, any of the RAN nodes 2A to 2G. Similarly, when describing matters common to multiple cells 21A to 21G, reference will be made to the cell 21 unless otherwise specified. The cell 21 may be, for example, any of the cells 21A to 21G.

[0053] The aerial UE 1 is a UE that supports aerial UE communication or is capable of aerial communication. The aerial UE 1 may be mounted on a UAV (such as a drone) or a manned aircraft (such as a helicopter or flying taxi). The aerial UE 1 may be an LTE aerial UE or an NR aerial UE. The aerial UE 1 may also be referred to by other terms, such as a UAV UE, a UAV radio terminal, aerial radio terminal, a UAV mobile terminal, aerial mobile terminal, a UAV mobile station, aerial mobile station, a UAV wireless transmit receive unit (WTRU), or aerial WTRU.

[0054] The RAN node 2 may also be referred to as a base station, radio station, or access point. The RAN node 2 may be an E-UTRAN node or an NG-RAN node. The E-UTRAN node may be an eNB or an en-gNB. The NG-RAN node may be a gNB or an ng-eNB. The RAN node 2 may be a combination of a Central Unit (CU) (e.g., gNB-CU) and one or more Distributed Units (DUs) (e.g., gNB-DUs) in a cloud RAN (C-RAN) deployment. The C-RAN is also referred to as a CU / DU split. Furthermore, the CU may include a Control Plane (CP) Unit (e.g., gNB-CU-CP) and one or more User Plane (UP) Units (e.g., gNB-CU-UPs).

[0055] RAN nodes 2A-2G provide cells 21A-21G, respectively. One RAN node 2 may provide multiple cells. At least two of the cells 21A-21G shown in FIG. 1 may be provided by one RAN node 2. The illustrated sizes of the cells 21A-21G are for illustrative purposes only. The sizes of the cells 21A-21G may differ from one another. For example, one of the cells 21A-21G may be a macrocell, another a microcell, and yet another a picocell. Any of the cells 21A-21G may be encompassed or covered by any of the others. The frequency bands (e.g., NR operating bands or NR Radio Frequency (RF) carriers) of the cells 21A-21G may differ from one another.

[0056] In the example of Fig. 1, the aerial UE 1 flies through cell 21A, cell 21B, and cell 21C in this order. In other words, the flight path of the aerial UE 1 includes waypoints in cell 21A, cell 21B, and cell 21C in this order. One waypoint is defined by its three-dimensional position. The flight path of the aerial UE 1 includes multiple waypoints, each defined as a three-dimensional position.

[0057] In the example of FIG. 1 , a no-transmission zone (NTZ) 3 specific to aerial UEs is defined. The geographical scope of NTZ 3 spans cells 21B, 21C, 21E, and 21G. As previously described, NTZ 3 is a geographical area where aerial UEs are not permitted to operate in a particular frequency band due to coexistence with other wireless systems and services, such as DTT receivers, RA sites, and radar sites. NTZ 3 can be defined and implemented at the national level. For example, NTZ 3 may be defined for aerial UEs operating in the 703-718 MHz frequency band around a RAS site operating in the 1400-1427 MHz frequency band. NTZ 3 may also be defined for aerial UEs operating in the 832-837 MHz frequency band around a RAS site operating in the 1660-1670 MHz frequency band. NTZ 3 may be defined for aerial UEs operating in the 2500-2570 MHz or 2570-2620 MHz frequency bands around a RAS site operating at 2690-2700 MHz, or alternatively, NTZ 3 may be defined for aerial UEs operating in the 2500-2570 MHz or 2570-2620 MHz frequency bands around a radar operating at 2700-2900 MHz.

[0058] The definition of the geographical shape of the NTZ 3 is not limited to that shown in the example of FIG. 1. In FIG. 1, the NTZ 3 may be defined as a three-dimensional area including a circular ground area with a predetermined radius centered on a predetermined point (e.g., a RAS site or a radar site) and an airspace above it up to a predetermined height. Alternatively, the NTZ 3 may be defined as a spherical three-dimensional area with a predetermined radius centered on the predetermined point. The NTZ 3 may also be defined as an ellipsoidal three-dimensional area centered on the predetermined point. The NTZ 3 may also be defined as a rectangular ground area with a predetermined point centered on the predetermined point and an airspace above it up to a predetermined height. The NTZ 3 may also be defined as a cubic or rectangular parallelepiped three-dimensional area centered on the predetermined point.

[0059] If we take a very strict understanding of NTZ 3, aerial UE 1 should not initially access cells within NTZ 3 or cells that partially overlap with NTZ 3 (e.g., cells 21B, 21C, 21E, and 21G in FIG. 1 ). In this case, aerial UE 1 cannot even camp on these cells that at least partially overlap with NTZ 3. In contrast, in a less strict scenario, aerial UE 1 can access these cells that at least partially overlap with NTZ 3, but is steered to another cell for further transmissions.

[0060] Two types of mechanisms are possible for the aerial UE 1 to respect NTZ 3: one is a cell-level granularity mechanism, and the other is a finer granularity mechanism. For example, at the cell-level granularity, one or more RAN nodes 2 may impose cell-level measures to prevent the aerial UE 1 from accessing NTZ-affected cells, such as cells 21B, 21C, 21E, and 21G in Figure 1.

[0061] At a finer granularity, an aerial UE 1 in RRC_CONNECTED mode may notify a RAN node 2 when the UE 1 enters or leaves an NTZ 3. The aerial UE 1 may use Global Navigation Satellite Systems (GNSS) location information to obtain its location. Signaling may be defined to notify a RAN node 2 when an aerial UE 1 in RRC_CONNECTED mode approaches or enters an NTZ 3. This allows the network (e.g., one or more RAN nodes 2) to make preparations to maintain connectivity with the aerial UE 1 (e.g., switch to another frequency band or carrier permitted within the NTZ 3). Conversely, knowing when the aerial UE 1 leaves the NTZ 3 allows the network (e.g., one or more RAN nodes 2) to restore the previous communication mode with the aerial UE 1.

[0062] The embodiments described below provide Air 1 and RAN node 2 operations, procedures and signaling that contribute to or assist in implementing mechanisms to enable Air UEs to respect NTZ.

[0063] <First Embodiment> A configuration example of a wireless communication system according to this embodiment is the same as the configuration example described with reference to Fig. 1. Fig. 2 shows an example of signaling between an aerial UE 1 and a RAN node 2. In step 201, the RAN node 2 (e.g., RAN node 2B in Fig. 1) transmits system information in a cell 21 (e.g., cell 21B in Fig. 1) via broadcast. The system information may be a Master Information Block (MIB) or any System Information Block (SIB) (e.g., SIB type 1 (SIB1) or SIB type 2 (SIB2)).

[0064] The system information in step 201 includes information indicating whether the cell is barred for aerial UEs. The information may be a single bit. The information may be an enumerated information element (IE) indicating "barred" or "not barred." The name of the IE may be, but is not limited to, "cellBarredUAV." The information or IE may apply to all Public Land Mobile Networks (PLMNs) and Non-Public Networks (NPNs) associated with the cell 21. The information or IE may be included in MIB or SIB1, as well as similar information elements indicating cell status and cell reservation (e.g., cellBarred IE, cellBarredNTN IE, cellBarredRedCap1Rx, cellReservedForOtherUse).

[0065] If the cell 21 is included in or partially overlaps with the NTZ 3 for aerial UEs and the uplink frequency of the cell 21 is within a frequency band prohibited by the NTZ 3, the RAN node 2 may indicate to the aerial UE 1 by the information or IE (e.g., cellBarredUAV) that the cell 21 is prohibited for the aerial UEs. Otherwise, the RAN node 2 may indicate to the aerial UE 1 by the information or IE that the cell 21 is not prohibited for the aerial UEs. Alternatively, the RAN node 2 may indicate that the cell 21 is not prohibited for the aerial UEs by not including the information or IE in the system information.

[0066] 3 shows an example of the operation of the aerial UE 1. In step 301, the aerial UE 1 receives system information (e.g., SIB1) via broadcast in the cell 21. In step 302, the aerial UE 1 determines whether the received system information includes an IE (e.g., cellBarredUAV) indicating whether the cell 21 is barred for aerial UEs.

[0067] If the system information includes this IE (YES in step 302) and this IE indicates that cell 21 is barred for aerial UEs (YES in step 303), the aerial UE 1 treats cell 21 as a barred cell in cell selection or cell reselection (step 304). In other words, the aerial UE 1 excludes cell 21 from candidate cells for cell selection or cell reselection. On the other hand, if the system information includes this IE (YES in step 302) and this IE indicates that cell 21 is not barred for aerial UEs (NO in step 303), the aerial UE 1 does not treat cell 21 as a barred cell in cell selection or cell reselection (step 305). In addition, if the system information does not include this IE (NO in step 302), the aerial UE 1 does not treat cell 21 as a barred cell in cell selection or cell reselection (step 305).

[0068] 2 and 3, the aerial UE 1 can assume that it is not barred from accessing a cell 21 if no information or IE (e.g., cellBarredUAV) indicating whether the cell 21 is barred for aerial UEs is broadcast in the cell 21. This helps clarify the signaling and UE operation details regarding the mechanism for enabling aerial UEs to respect the NTZ.

[0069] <Second Embodiment> A configuration example of a wireless communication system according to this embodiment is the same as the configuration example described with reference to Fig. 1. Figs. 4, 5, and 6 show an example of signaling between an aerial UE 1 and a RAN node 2. In steps 401, 501, and 601, the RAN node 2 (e.g., RAN node 2B in Fig. 1) transmits NTZ-related information in a cell 21 (e.g., cell 21B in Fig. 1) via broadcast. The NTZ-related information may be included in system information (e.g., MIB, SIB1, or other SIB).

[0070] In the example of Figure 4, the NTZ-related information (step 401) indicates that cell 21 belongs to or includes NTZ 3 for the aerial UEs. In other words, the NTZ-related information (step 401) indicates that at least a portion of cell 21 overlaps with NTZ 3. If aerial UE 1 receives the NTZ-related information (step 401) in cell 21, aerial UE 1 may understand that uplink transmissions in the cell are not permitted for the aerial UEs. More specifically, aerial UE 1 may understand that initial access from RRC_IDLE, RRC re-establishment, RRC resume from RRC_INACTIVE, and random access related to all uplink transmissions of the aerial UEs are restricted in cell 21.

[0071] 5, the NTZ-related information (step 501) indicates that uplink transmissions are not permitted for air UEs in cell 21. If air UE 1 receives the NTZ-related information (step 501) in cell 21, air UE 1 may understand that uplink transmissions are not permitted for air UEs in the cell. More specifically, air UE 1 may understand that initial access from RRC_IDLE, RRC re-establishment, RRC resume from RRC_INACTIVE, and random access related to all uplink transmissions of air UEs are restricted in cell 21.

[0072] In the example of Figure 6, the NTZ-related information (step 601) indicates that cell 21 provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. Such a cell may be called a supplementary downlink cell. If aerial UE 1 receives the NTZ-related information (step 601) in cell 21, aerial UE 1 may understand that downlink data reception is permitted in cell 21 but uplink data transmission is not permitted.

[0073] The aerial UE 1 may take the NTZ-related information (step 401, 501, or 601) into consideration for one or both of cell selection and cell reselection. For example, the aerial UE 1 may preferentially select a cell that does not transmit NTZ-related information over a cell that transmits NTZ-related information in cell selection or reselection. For example, if SIB2 includes the rangeToBestCell field, the aerial UE 1 may perform cell reselection to a cell that does not transmit NTZ-related information among multiple candidate cells whose R value, calculated using the average Reference Signal Received Power (RSRP), is within the range specified in the rangeToBestCell field from the R value of the highest cell. Alternatively, the aerial UE 1 may treat a cell that transmits NTZ-related information (step 401, 501, or 601) as a forbidden cell in cell selection or cell reselection.

[0074] The NTZ-related information may be an enumerated IE and may indicate "True." The name of the IE may be, for example, but not limited to, "noTransmitZoneUAV," "noRachULtransmitUAV," or "supplementaryDLUAV." The information or IE may apply to all PLMNs and NPNs associated with the cell 21. The information or IE may be included in MIB or SIB1, as well as similar information elements indicating cell status and cell reservation (e.g., cellBarred IE, cellBarredNTN IE, cellBarredRedCap1Rx, cellReservedForOtherUse).

[0075] If the cell 21 is covered by or partially overlaps with the NTZ 3 for aerial UEs and the uplink frequency of the cell 21 is within the frequency band prohibited by the NTZ 3, the RAN node 2 may broadcast the above-mentioned NTZ-related information in the cell 21. Otherwise, the RAN node 2 may indicate that the cell 21 is not prohibited for aerial UEs by not transmitting the above-mentioned NTZ-related information in the cell 21.

[0076] According to the operations described with reference to Figures 4, 5 and 6, the RAN node 2 can indicate to the aerial UEs via broadcast whether the cell 21 is within the NTZ for the aerial UEs, whether uplink transmissions by the aerial UEs in the cell 21 are prohibited, or whether the cell 21 is dedicated to downlink services for the aerial UEs. This contributes to clarifying the signaling details regarding the mechanism for enabling the aerial UEs to respect the NTZ.

[0077] <Third Embodiment> A configuration example of a wireless communication system according to this embodiment is the same as the configuration example described with reference to Fig. 1. Fig. 7 shows an example of signaling between an aerial UE 1 and a RAN node 2. In step 701, the RAN node 2 (e.g., RAN node 2A in Fig. 1) transmits an excluded cell list specific to the aerial UEs in its own cell 21 (e.g., cell 21A in Fig. 1). The RAN node 2 (e.g., RAN node 2A in Fig. 1) may include one or more neighboring cells (e.g., cell 21B in Fig. 1) that at least partially overlap with NTZ 3 and whose uplink frequencies are within the frequency band prohibited by NTZ 3 in the excluded cell list specific to the aerial UEs.

[0078] The RAN node 2 may transmit the excluded cell list specific to the aerial UEs via a dedicated Radio Resource Control (RRC) message to the aerial UE 1 or via common system information within the cell 21. The RAN node 2 may transmit or broadcast the excluded cell list specific to the aerial UEs via SIB type 3 (SIB3) or SIB type 4 (SIB4).

[0079] The aerial UE 1 may exclude one or more cells included in the received excluded cell list from candidate cells for cell reselection. Additionally or alternatively, the aerial UE 1 may exclude cells included in the received excluded cell list from candidates for primary cells for carrier aggregation. Additionally or alternatively, the aerial UE 1 may exclude one or more cells included in the received excluded cell list from targets of Radio Resource Management (RRM) measurements for cell reselection. Additionally or alternatively, the aerial UE 1 may exclude one or more cells included in the received excluded cell list from targets of IDLE / INACTIVE measurements. IDLE / INACTIVE measurement is a function introduced in 3GPP Release 16. IDLE / INACTIVE measurement is a function that acquires and stores measurement results of serving cells and neighboring cells while the UE 1 is in the RRC_IDLE or RRC_INACTIVE state, and transmits the stored measurement results to the network when the UE 1 is in the RRC_CONNECTED state.

[0080] According to the operations described with reference to Figure 7, the RAN node 2 can transmit an excluded cell list specific to the aerial UEs in its cell 21. This contributes to clarifying the signaling details regarding the mechanisms for enabling the aerial UEs to respect the NTZ, in particular the signaling details regarding the cell reselection of the aerial UEs.

[0081] FIG. 8 shows an example of the format of the SIB3 information element (IE). The SIB3 IE contains neighbor cell-related information relevant only to intra-frequency cell reselection. The SIB3 IE contains cells with specific reselection parameters and excluded (exclude-listed) cells. In the example of FIG. 8, the SIB3 IE may contain an intraFreqExcludedCellListUAV field 801. The intraFreqExcludedCellListUAV field 801 is an IntraFreqExcludedCellListUAV IE 802. The IntraFreqExcludedCellListUAV IE 802 is an example of the excluded cell list of step 701, i.e., an excluded cell list specific to aerial UEs. The IntraFreqExcludedCellListUAV IE 802 indicates one or more neighbor cells to be excluded in intra-frequency cell reselection by aerial UEs. The names of field 801 and IE 802 are merely examples and may be different.

[0082] FIG. 9 shows an example of the format of the SIB4 IE. The SIB4 IE includes information related to inter-frequency cell reselection (i.e., information about other NR frequencies related to cell reselection and inter-frequency neighboring cells). The SIB4 IE can also be used for IDLE / INACTIVE measurements. The SIB4 IE includes cell reselection parameters common to a certain frequency and cell-specific reselection parameters. In the example of FIG. 9, the SIB4 IE can include an interFreqExcludedCellListUAV field 901. The interFreqExcludedCellListUAV field 901 is an InterFreqExcludedCellListUAV IE 902. The InterFreqExcludedCellListUAV IE 902 is an example of the excluded cell list of step 701, i.e., an excluded cell list specific to aerial UEs. The InterFreqExcludedCellListUAV IE 902 indicates a list of one or more neighboring cells to be excluded in inter-frequency cell reselection by aerial UEs. Additionally, the InterFreqExcludedCellListUAV IE 902 indicates one or more neighboring cells that are excluded from IDLE / INACTIVE measurements by aerial UEs. The names of the field 901 and the IE 902 are merely examples and may be different names.

[0083] Fourth Embodiment A configuration example of a wireless communication system according to this embodiment is similar to the configuration example described with reference to Fig. 1. Fig. 10 shows an example of signaling between an aerial UE 1 and a RAN node 2. In step 1001, the RAN node 2 (e.g., RAN node 2A in Fig. 1) transmits a neighbor cell list specific to the aerial UEs in its own cell 21 (e.g., cell 21A in Fig. 1). Each of the one or more cells included in this neighbor cell list is a cell that belongs to or includes the NTZ 3 for the aerial UEs, a cell that is not permitted for uplink transmission to the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs. The RAN node 2 (e.g., RAN node 2A in Fig. 1) may include in this neighbor cell list one or more neighbor cells (e.g., cell 21B in Fig. 1) that at least partially overlap with the NTZ 3 and whose uplink frequencies are within a frequency band prohibited by the NTZ 3.

[0084] The RAN node 2 may transmit the neighbor cell list specific to the aerial UEs via a dedicated Radio Resource Control (RRC) message to the aerial UE 1 or via common system information within the cell 21. The RAN node 2 may transmit or broadcast the neighbor cell list specific to the aerial UEs via SIB3 or SIB4.

[0085] The aerial UE 1 may exclude one or more cells included in the received neighbor cell list from candidate cells for cell reselection. Additionally or alternatively, the aerial UE 1 may exclude cells included in the received neighbor cell list from candidate cells for primary cell of carrier aggregation. Additionally or alternatively, the aerial UE 1 may exclude one or more cells included in the received neighbor cell list from targets of RRM measurement for cell reselection. Additionally or alternatively, the aerial UE 1 may exclude one or more cells included in the received neighbor cell list from targets of IDLE / INACTIVE measurement.

[0086] According to the operation described with reference to Figure 10, the RAN node 2 can transmit a neighbor cell list specific to the aerial UEs in its cell 21. This allows the RAN node 2 to inform the aerial UEs belonging to its cell 21 of neighbor cells that belong to or include the NTZ 3 for the aerial UEs, neighbor cells from which the aerial UEs are not permitted to transmit uplink, or neighbor cells that provide downlink communication services to the aerial UEs but not uplink communication services to the aerial UEs. This contributes to clarifying the signaling details regarding mechanisms for enabling aerial UEs to respect the NTZ, in particular the signaling details regarding cell reselection of the aerial UEs.

[0087] Figure 11 shows an example of the format of the SIB3 IE. The SIB3 IE contains neighbor cell-related information relevant only to intra-frequency cell reselection. The SIB3 IE includes cells with specific reselection parameters and exclude-listed cells. In the example of Figure 11, the SIB3 IE can include an intraFreqnoRachULtransmitUAV field 1101. The intraFreqnoRachULtransmitUAV field 1101 is an IntraFreqnoRachULtransmitUAV IE 1102. The IntraFreqnoRachULtransmitUAV IE 1102 is an example of the neighbor cell list of step 1001, i.e., a neighbor cell list specific to aerial UEs. The IntraFreqnoRachULtransmitUAV IE 1102 indicates one or more intra-frequency neighbor cells to which aerial UEs are prohibited from random access transmission. The names of the field 1101 and the IE 1102 are merely examples and may be other names, for example, IntraFreqnoTransmitZoneUAV or IntraFreqsupplementaryDLUAV.

[0088] FIG. 12 shows an example of the format of the SIB4 IE. The SIB4 IE includes information related to inter-frequency cell reselection (i.e., information about other NR frequencies and inter-frequency neighboring cells related to cell reselection). The SIB4 IE can also be used for IDLE / INACTIVE measurements. The SIB4 IE includes cell reselection parameters common to a certain frequency and cell-specific reselection parameters. In the example of FIG. 12, the SIB4 IE can include an interFreqnoRachULtransmitUAV field 1201. The interFreqnoRachULtransmitUAV field 1201 is an InterFreqnoRachULtransmitUAV IE 1202. The InterFreqnoRachULtransmitUAV IE 1202 is an example of the neighbor cell list of step 1001, i.e., a neighbor cell list specific to aerial UEs. The InterFreqnoRachULtransmitUAV IE 1202 indicates one or more inter-frequency neighboring cells to which random access transmissions by airborne UEs are prohibited. The names of field 1201 and IE 1202 are merely examples and may be other names. For example, these names may be InterFreqnoTransmitZoneUAV or InterFreqsupplementaryDLUAV.

[0089] Fifth Embodiment A configuration example of a wireless communication system according to this embodiment is similar to the configuration example described with reference to Fig. 1. Fig. 13 shows an example of signaling between two RAN nodes 2. In step 1301, the RAN node 2A sends information indicating whether a cell 21A provided by the RAN node 2A at least partially overlaps with NTZ 3 to a neighboring RAN node 2B. If the cell 21A at least partially overlaps with NTZ 3 and the uplink frequency of the cell 21A is included in a frequency band prohibited by NTZ 3, the RAN node 2A may inform the RAN node 2B that the cell 21A at least partially overlaps with NTZ 3. Otherwise, the RAN node 2A may inform the RAN node 2B that the cell 21A does not even partially overlap with NTZ 3.

[0090] In step 1302, RAN node 2A receives from neighboring RAN node 2B information indicating whether cell 21B provided by neighboring RAN node 2B at least partially overlaps with NTZ 3. RAN node 2B may inform RAN node 2A that cell 21B at least partially overlaps with NTZ 3 if cell 21B at least partially overlaps with NTZ 3 and the uplink frequency of cell 21B is included in a frequency band prohibited by NTZ 3. Otherwise, RAN node 2B may inform RAN node 2A that cell 21B does not even partially overlap with NTZ 3.

[0091] The order of steps 1301 and 1302 is not limited. The control message carrying information in each of steps 1301 and 1302 may be an Xn Application Protocol (XnAP) message, and more specifically, may be, for example, an XN SETUP REQUEST, an XN SETUP RESPONSE, an NG-RAN NODE CONFIGURATION UPDATE, or an ACCESS AND MOBILITY INDICATION message.

[0092] In addition, the RAN node 2A may send to the RAN node 2B information indicating whether each of neighboring cells of its own cell 21A, specifically one or more cells 21 (e.g., cells 21D and 21F in FIG. 1 ) provided by one or more neighboring RAN nodes other than the RAN node 2B (e.g., RAN nodes 2D and 2F in FIG. 1 ), at least partially overlaps with the NTZ 3. The RAN node 2A may receive this information from the RAN nodes 2D and 2F. The RAN node 2A may send the information regarding the overlap between the neighboring cells and the NTZ to the RAN node 2B using the message for sending information regarding the overlap between its own cell 21A and the NTZ in step 1301. Alternatively, the RAN node 2A may send these information to the RAN node 2B in separate messages.

[0093] Similarly, the RAN node 2B may send to the RAN node 2A information indicating whether each of neighboring cells of its own cell 21B, specifically one or more cells 21 (e.g., cells 21C, 21E, and 21G in FIG. 1 ) provided by one or more neighboring RAN nodes other than the RAN node 2A (e.g., RAN nodes 2C, 2E, and 2G in FIG. 1 ), at least partially overlaps with the NTZ 3. The RAN node 2B may receive this information from the RAN nodes 2C, 2E, and 2G. The RAN node 2B may send information regarding the overlap between neighboring cells and the NTZ to the RAN node 2A using the message for sending information regarding the overlap between its own cell 21B and the NTZ in step 1302. Alternatively, the RAN node 2B may send these information to the RAN node 2A in separate messages.

[0094] According to the operations described with reference to Figure 13, the RAN node 2A can exchange or share with neighbouring RAN node 2B information about the overlap between cell 21 and NTZ 3. This contributes to clarifying the signalling details regarding the mechanism for enabling aerial UEs to respect the NTZ.

[0095] The RAN node 2A may use the information regarding the overlap between the neighboring cell 21B and the NTZ 3 received from the RAN node 2B for various purposes or applications. For example, as shown in Figure 14, the RAN node 2A may take this information into consideration or use it to determine a target cell for handover of the aerial UE 1 in the RRC_CONNECTED state. The handover may be a conditional handover (CHO). Additionally or alternatively, as shown in Figure 15, the RAN node 2A may take this information into consideration or use it to generate an excluded cell list or neighboring cell list specific to the aerial UEs, which may be similar to that described in the third or fourth embodiment.

[0096] 14 shows an example of the operation of the RAN node 2A. In step 1401, the RAN node 2A determines a handover of the aerial UE 1 in the RRC_CONNECTED state. The handover may be a conditional handover (CHO). The RAN node 2A may determine the handover of the aerial UE 1 based at least on receiving a measurement report from the aerial UE 1. The RAN node 2A may determine the handover of the aerial UE 1 based at least on flight path information of the aerial UE 1 received from the aerial UE 1.

[0097] In step 1402, the RAN node 2A attempts to select a target cell that does not overlap even partially with the NTZ 3. If a target cell that does not overlap even partially with the NTZ 3 is selected, the RAN node 2A prepares a handover or CHO to the target cell. Then, the RAN node 2A transmits configuration information for the handover or CHO to the aerial UE 1. In response to receiving the configuration information for the handover, the aerial UE 1 leaves the cell 21A and starts accessing the target cell. Alternatively, the aerial UE 1 leaves the cell 21A and starts accessing the target cell in response to the CHO execution condition being met after receiving the configuration information for CHO.

[0098] On the other hand, if the RAN node 2A cannot select a target cell that does not overlap even partially with the NTZ 3, in step 1403, the RAN node 2A sends a message to the aerial UE 1 to release the RRC connection of the aerial UE 1. The message may be an RRCRelease message. The RAN node 2A includes in the message a cause value indicating that the release of the RRC connection is due to entry into the NTZ. In other words, the message indicates that the release of the RRC connection is due to entry into the NTZ.

[0099] According to the operations described with reference to Figure 14, the RAN node 2A can take into account or use information about the overlap between neighboring cells and the NTZ to determine a target cell for handover of the aerial UE 1. This contributes to clarifying the details of operations and signaling related to mechanisms for enabling aerial UEs to respect the NTZ, in particular the operations and signaling related to handover of aerial UEs.

[0100] Figure 15 shows an example of the operation of the RAN node 2A. In step 1501, the RAN node 2A generates a neighbor cell list (or neighbor cell list) specific to aerial UEs based on information received from a neighboring RAN node 2B regarding overlap with the NTZ 3. In step 1502, the RAN node 2A broadcasts the generated neighbor cell list (or neighbor cell list) in its own cell 21A.

[0101] The excluded cell list specific to the aerial UEs may be similar to that described in the third embodiment. Specifically, the excluded cell list specific to the aerial UEs may indicate one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs. The RAN node 2A may include in the excluded cell list cells that at least partially overlap with the NTZ 3 and whose uplink frequencies are included in the frequency band prohibited by the NTZ 3.

[0102] On the other hand, the neighbor cell list specific to the aerial UEs may be the same as that described in the fourth embodiment. Specifically, each of the one or more cells included in the neighbor cell list specific to the aerial UEs may be a cell belonging to or including NTZ 3, a cell in which uplink transmission is not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs. The neighbor cell list specific to the aerial UEs may cause the aerial UEs to exclude one or more cells included in the neighbor cell list from candidate cells for cell reselection. Additionally or alternatively, the neighbor cell list specific to the aerial UEs may cause the aerial UEs to exclude cells included in the neighbor cell list from candidate primary cells for carrier aggregation. The RAN node 2A may include in the neighbor cell list cells that at least partially overlap with NTZ 3 and whose uplink frequencies are included in a frequency band prohibited by NTZ 3.

[0103] According to the operations described with reference to Figure 15, the RAN node 2A can take into account or use information about the overlap of the NTZ with neighboring cells to control cell reselection of the aerial UE 1. This contributes to clarifying the details of operations and signaling related to mechanisms for enabling aerial UEs to respect the NTZ, in particular the operations and signaling related to cell reselection of the aerial UEs.

[0104] FIG. 16 shows an example of the format of the Served Cell Information NR IE. The Served Cell Information NR IE includes cell configuration information of the NR cell that neighboring NG-RAN nodes require for the XnAP interface. The Served Cell Information NR IE can be included, for example, in the XN SETUP REQUEST, XN SETUP RESPONSE, NG-RAN NODE CONFIGURATION UPDATE, and NG-RAN NODE CONFIGURATION UPDATE ACKNOWLEDGE messages. In the example of FIG. 16, the Served Cell Information NR IE can include a UAVNotransmitZone IE 1601. The UAVNotransmitZone IE 1601 indicates whether the NR cell to which the Served Cell Information NR IE is associated at least partially overlaps with the NTZ for aerial UEs. The UAVNotransmitZone IE 1601 may be an enumerated type and may indicate "false" or "true."

[0105] FIG. 17 shows an example of the format of the Neighbor Information NR IE. The Neighbor Information NR IE includes cell configuration information of an NR cell that is required for neighboring NG-RAN nodes to properly operate their serving cells. The Neighbor Information NR IE can be included, for example, in the XN SETUP REQUEST, XN SETUP RESPONSE, NG-RAN NODE CONFIGURATION UPDATE, and NG-RAN NODE CONFIGURATION UPDATE ACKNOWLEDGE messages. In the example of FIG. 17, the Neighbor Information NR IE can include a UAVNotransmitZone IE 1701 for each of one or more neighboring NR cells. The UAVNotransmitZone IE 1701 indicates whether the associated neighboring NR cell at least partially overlaps with the NTZ for aerial UEs. The UAVNotransmitZone IE 1701 can be an enumerated type and can indicate "false" or "true."

[0106] Sixth Embodiment A configuration example of a wireless communication system according to this embodiment is similar to the configuration example described with reference to FIG. 1. The RAN node 2 may have the configuration shown in FIG. 18. Each element (network function) shown in FIG. 18 can be implemented, for example, as a network element on dedicated hardware, as a software instance running on dedicated hardware, or as a virtualized function instantiated on an application platform. The RAN node 2 may include a CU 22 and one or more DUs 23 (e.g., DUs 23A to 23C) as shown in FIG. 18. Hereinafter, when describing matters common to multiple DUs 23A to 23C, the DU 23 will be referred to unless otherwise specified. The CU 22 and each DU 23 are connected by an interface 24. An aerial UE 1 is connected to at least one DU 23 via at least one air interface 25.

[0107] The CU 22 may be a logical node that hosts the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols (or the RRC and PDCP protocols) of the gNB. The DU 23 may be a logical node that hosts the Radio Link Control (RLC), Medium Access Control (MAC), and Physical (PHY) layers of the gNB. If the CU 22 is a gNB-CU and the DUs 23 are gNB-DUs, the interface 24 may be an F1 interface. The CU 22 may include a CU-CP and a CU-UP.

[0108] 19 shows an example of signaling between a CU 22 and a DU 23. In step 1901, the CU 22 sends to the DU 23 first information indicating whether a cell 21 provided by or associated with the DU 23 at least partially overlaps with the NTZ 3 for aerial UEs. The CU 22 may send the first information to the DU 23 via an F1 SETUP RESPONSE, a GNB-DU CONFIGURATION UPDATE ACKNOWLEDGE, or a GNB-CU CONFIGURATION UPDATE message. The CU 22 may include the first information in a Cells to be Activated List IE that can be included in these F1 Application Protocol (F1AP) messages. The Cells to be Activated List IE contains a list of cells that the CU 22 requests the DU 23 to activate.

[0109] The DU 23 may use the received first information for various purposes or applications. In one example, the DU 23 may take the first information into consideration when determining whether to steer the aerial UE 1 in an RRC_CONNECTED state in its own cell 21 to another cell. The DU 23 may change the serving cell of the aerial UE 1 using L1 / L2-triggered Mobility (LTM). LTM is a procedure in which the gNB receives L1 measurement reports from the UE and, based on the L1 measurement reports, the gNB changes one or more serving cells of the UE through L2 signaling, specifically, a MAC Control Element (CE).

[0110] 19, the CU 22 can inform a DU 23 whether a cell 21 provided by or associated with the DU 23 at least partially overlaps with the NTZ 3 for aerial UEs. This contributes to clarifying the signaling details related to mechanisms for enabling aerial UEs to respect the NTZ, in particular the signaling details related to mobility procedures (e.g., LTM) of aerial UEs.

[0111] In addition, the CU 22 may transmit, to the DU 23 (e.g., DU 23A), second information indicating whether one or more neighboring cells provided by one or more other DUs 23 (e.g., DUs 23B and 23C) at least partially overlap with the NTZ 3. Figure 20 shows an example of signaling between the CU 22 and the DU 23. In step 2001, the CU 22 transmits, to the DU 23 (e.g., DU 23A), second information indicating whether one or more neighboring cells at least partially overlap with the NTZ 3 for the aerial UEs. The CU 22 may transmit the second information to the DU 23 via an F1 SETUP RESPONSE, a GNB-DU CONFIGURATION UPDATE ACKNOWLEDGE, or a GNB-CU CONFIGURATION UPDATE message. The CU 22 may include the second information in a Neighbor Cell Information List IE that may be included in these F1 Application Protocol (F1AP) messages.

[0112] The DU 23 can use the received second information for various purposes or applications. In one example, the DU 23 may take into account or use the second information when determining another cell to guide the aerial UE 1 that is in an RRC_CONNECTED state in its own cell 21. The DU 23 may take into account or use the second information to determine a target cell for LTM.

[0113] According to the operation described with reference to Figure 20, the CU 22 can inform the DU 23 whether one or more neighboring cells at least partially overlap with the NTZ 3 for the aerial UEs. This contributes to clarifying the signaling details regarding mechanisms for enabling the aerial UEs to respect the NTZ, in particular the signaling details regarding the mobility procedures (e.g., LTM) of the aerial UEs.

[0114] The procedure of Fig. 19 described above may be used in a case or scenario in which the CU 22 sets or determines information on whether a cell at least partially overlaps with the NTZ 3. In contrast, a case or scenario in which the DU 23 sets or determines information on whether a cell at least partially overlaps with the NTZ 3 may also be considered. In this case, the CU 22 and the DU 23 may perform the procedure shown in Fig. 21.

[0115] 21 shows an example of signaling between a CU 22 and a DU 23. In step 2101, the DU 23 sends to the CU 22 first information indicating whether the cell 21 it serves or is associated with at least partially overlaps with the NTZ 3 for aerial UEs. The DU 23 may send the first information to the CU 22 via an F1 SETUP REQUEST or GNB-DU CONFIGURATION UPDATE message. The DU 23 may include the first information in a Served Cell Information IE that can be included in these F1 Application Protocol (F1AP) messages.

[0116] The CU 22 can use the received first information for various purposes or applications. In one example, the CU 22 may consider or use the received first information when determining a target cell for intra-CU inter-DU handover or CHO. In intra-CU inter-DU handover or CHO, the CU 22 may attempt to select a target cell that does not overlap even partially with the NTZ 3. Additionally or alternatively, the CU 22 may consider or use the received first information to determine the content of system information (e.g., the system information described in the first or second embodiment) broadcast in one or more cells 21 provided by one or more DUs 23. Additionally or alternatively, the CU 22 may consider or use the received first information to determine the content of an excluded cell list or neighbor cell list (e.g., the excluded cell list or neighbor cell list described in the third or fourth embodiment) specific to aerial UEs. Additionally or alternatively, the CU 22 may consider or use the first information received from one DU 23 to send the above-mentioned second information (FIG. 20) to another DU 23.

[0117] According to the operation described with reference to Figure 21, a DU 23 can inform a CU 22 whether a cell 21 provided by or associated with the DU 23 at least partially overlaps with an NTZ 3 for an aerial UE. This contributes to clarifying details of signaling related to mechanisms for enabling aerial UEs to respect the NTZ, in particular signaling related to mobility procedures (e.g., cell reselection, handover, CHO) of the aerial UEs.

[0118] Seventh Embodiment A configuration example of a wireless communication system according to this embodiment is similar to the configuration example described with reference to Fig. 1. Fig. 22 shows an example of signaling between an aerial UE 1 and a RAN node 2. In step 201, the RAN node 2 transmits NTZ-related information to the aerial UE 1, the NTZ-related information including geographic information for defining the geographic range of an NTZ 3 for the aerial UEs. The NTZ-related information may further include information indicating one or more frequency bands (e.g., NR operating bands or NR RF carriers) on which the aerial UEs are not permitted to transmit in the NTZ 3 (e.g., NR frequency band number(s) or NR Absolute Radio Frequency Channel Numbers (ARFCNs)). The RAN node 2 may broadcast the NTZ-related information via cell- or area-wide system information (e.g., SIB) or transmit it to the aerial UE 1 via a UE-dedicated RRC message.

[0119] The RAN node 2 in Figure 22 (e.g., RAN node 2A in Figure 1) may transmit NTZ-related information to aerial UE 1 in a cell 21 (e.g., cell 21A in Figure 1) that does not overlap even partially with NTZ 3. Additionally or alternatively, the RAN node 2 (e.g., RAN node 2B in Figure 1) may transmit NTZ-related information to aerial UE 1 in a cell 21 (e.g., cell 21B in Figure 1) that at least partially overlaps with NTZ 3.

[0120] As already described, there are several examples of the geographical shape of the NTZ 3. Specifically, for example, the NTZ 3 may be defined as a three-dimensional area including a circular ground area with a predetermined radius centered on a predetermined point (e.g., a RAS site or a radar site) and an airspace above it up to a predetermined height. Alternatively, the NTZ 3 may be defined as a spherical three-dimensional area with a predetermined radius centered on a predetermined point. The NTZ 3 may be defined as an ellipsoidal three-dimensional area centered on a predetermined point. The NTZ 3 may be defined as a rectangular ground area with a predetermined point centered on a predetermined point and an airspace above it up to a predetermined height. The NTZ 3 may also be defined as a cubic or rectangular parallelepiped three-dimensional area centered on a predetermined point.

[0121] The geographic information for defining the geographic range of the NTZ 3 includes information necessary to define these geographic shapes. For example, the geographic information may include latitude and longitude information for defining the location and range of the geographic range of the NTZ 3. The geographic information may specify the latitude and longitude of the start and end points for defining the ground range of the NTZ 3, as well as the start and end heights for defining the altitude range of the NTZ 3. The geographic information may specify the two-dimensional shape of the NTZ 3 (e.g., circle, ellipse, rectangle), the latitude and longitude of the center point of the two-dimensional shape, and the start and end heights for defining the altitude range of the NTZ 3. The geographic information may specify the three-dimensional shape of the NTZ 3 (e.g., sphere, ellipsoid, cube, rectangular prism) and the latitude and longitude of the center point of the three-dimensional shape.

[0122] According to the operations described with reference to Figure 22, the RAN node 2 can inform the aerial UE 1 of the specific geographical extent of the NTZ 3. This contributes to clarifying the signaling details regarding the mechanism for enabling aerial UEs to respect the NTZ. The aerial UE 1 can use or consider the specific geographical extent of the NTZ 3 for various purposes or uses. The following are examples of these purposes or uses:

[0123] The aerial UE 1 may use or consider the geographical information of the NTZ 3 to send a report regarding its approach or entry into the NTZ 3 to the RAN node 2 of the serving cell. The aerial UE 1 may also use GNSS location information to acquire its own location. FIG. 23 illustrates an example of the operation of the aerial UE 1 and the RAN node 2. FIG. 23 assumes that the aerial UE 1 is in the RRC_CONNECTED state. In step 2301, the aerial UE 1 may receive geographical information for defining the geographical range of the NTZ 3 from the serving RAN node 2. However, step 2301 may be omitted. Specifically, the aerial UE 1 may receive the geographical information of the NTZ 3 from the serving RAN node 2 of FIG. 23 in advance when in the RRC_IDLE or RRC_INACTIVE state. Alternatively, the aerial UE 1 may receive the geographical information of the NTZ 3 from another RAN node 2 before starting communication with the RAN node 2 of FIG. 23.

[0124] In step 2302, the aerial UE 1 detects approaching or entering the NTZ 3 based on the geographic information of the NTZ 3. The aerial UE 1 may detect that the aerial UE 1 is approaching, entering, or has entered the NTZ 3. In step 2303, the aerial UE 1 transmits a report regarding the approaching or entering the NTZ 3 to the RAN node 2 of the serving cell 21. The aerial UE 1 may transmit the report to the RAN node 2 of the serving cell 21 if the serving cell 21 operates in a frequency band that is prohibited for use in the NTZ 3.

[0125] Prior to step 2302, the serving RAN node 2 may configure the aerial UE 1 to send a report regarding its approach or entry into the NTZ 3. The serving RAN node 2 may configure the aerial UE 1 to send such a report if the serving cell 21 operates in a frequency band that is prohibited for use within the NTZ 3.

[0126] In one example, to receive a report regarding approaching or entering the NTZ 3, the serving RAN node 2 may use a UE Assistance Information procedure. Specifically, the serving RAN node 2 may configure the aerial UE 1 to report UE assistance information using an RRCReconfiguration message. The serving RAN node 2 may configure the aerial UE 1 with a condition or event that triggers the reporting of UE assistance information. In this case, the serving RAN node 2 configures the aerial UE 1 with a condition or event that triggers the reporting of UE assistance information regarding approaching or entering the NTZ 3. This condition or event may be that the distance between the aerial UE 1 and the NTZ 3 (or the reference position of the NTZ 3) falls below a threshold. The aerial UE 1 transmits a report regarding approaching or entering the NTZ 3 as UE assistance information to the serving RAN node 2 based on the configuration by the serving RAN node 2. That is, the aerial UE 1 sends the report to the serving RAN node 2 via a UEAssistanceInformation message.

[0127] In another example, the serving RAN node 2 may use a measurement reporting procedure to receive a report regarding approaching or entering the NTZ 3. Specifically, the serving RAN node 2 may configure a condition or event that triggers a measurement report in the aerial UE 1 using an RRCReconfiguration message. In this case, the serving RAN node 2 configures a condition or event that triggers a measurement report regarding approaching or entering the NTZ 3 in the aerial UE 1. This condition or event may be that the distance between the aerial UE 1 and the NTZ 3 (or the reference position of the NTZ 3) falls below a threshold. The aerial UE 1 transmits a report regarding approaching or entering the NTZ 3 to the serving RAN node 2 as a measurement report based on the configuration by the serving RAN node 2. That is, the aerial UE 1 transmits the report to the serving RAN node 2 via a MeasurementReport message.

[0128] In response to receiving the report regarding the approaching or entering NTZ 3, the serving RAN node 2 may perform procedures or actions to continue uplink communications for the aerial UE 1. For example, as shown in step 2304, based on or in response to receiving the report regarding the approaching or entering NTZ 3, the serving RAN node 2 may handover the aerial UE 1 to another cell operating in a frequency band that is not prohibited for use in NTZ 3. Alternatively, the serving RAN node 2 may add the other cell operating in a frequency band that is not prohibited for use in NTZ 3 as a secondary cell group cell for dual connectivity for the aerial UE.

[0129] According to the operation shown in Figure 23, Aerial UE 1 can use or take into account the geographical information of NTZ 3 to send a report to the network regarding its approach or entry into NTZ 3. This contributes to clarifying the signaling details regarding the mechanism for enabling Aerial UEs to respect the NTZ.

[0130] The aerial UE 1 may use or consider the geographical information of the NTZ 3 to send a report regarding exit from the NTZ 3 to the RAN node 2 of the serving cell. The aerial UE 1 may also use GNSS location information to acquire its own location. FIG. 24 illustrates an example of the operation of the aerial UE 1 and the RAN node 2. FIG. 24 assumes that the aerial UE 1 is in the RRC_CONNECTED state. In step 2401, the aerial UE 1 may receive geographical information for defining the geographical range of the NTZ 3 from the serving RAN node 2. However, step 2401 may be omitted. Specifically, the aerial UE 1 may receive the geographical information of the NTZ 3 from the serving RAN node 2 of FIG. 24 in advance when in the RRC_IDLE or RRC_INACTIVE state. Alternatively, the aerial UE 1 may receive the geographical information of the NTZ 3 from another RAN node 2 before starting communication with the RAN node 2 of FIG. 24.

[0131] In step 2402, the aerial UE 1 detects an exit from the NTZ 3 based on the geographic information of the NTZ 3. The aerial UE 1 may detect that the aerial UE 1 is exiting or has exited the NTZ 3. In step 2403, the aerial UE 1 sends a report regarding the exit from the NTZ 3 to the RAN node 2 of the serving cell 21.

[0132] Prior to step 2402, the serving RAN node 2 may configure the aerial UE 1 to send a report regarding exit from NTZ 3. Note that the serving cell 21 may be a cell operating in a frequency band that is not prohibited for use in NTZ 3. Alternatively, the serving cell 21 may be a cell operating in a frequency band that is prohibited for use in NTZ 3. In this case, the serving RAN node 2 may send the configuration for the report to the UE 1 in the serving cell 21 while the aerial UE 1 is still outside NTZ 3. Similar to the example of Fig. 23, the serving RAN node 2 may use the UE Assistance Information procedure or the Measurement Report procedure to receive the report regarding exit from NTZ 3.

[0133] In response to receiving the report regarding the exit from NTZ 3, serving RAN node 2 may perform procedures or actions to restore or resume previous uplink communications for aerial UE 1. For example, as shown in step 2404, serving RAN node 2 may handover aerial UE 1 to another cell operating in a frequency band that is prohibited for use within NTZ 3.

[0134] According to the operation shown in Figure 24, Aerial UE 1 can use or take into account the geographical information of NTZ 3 to send a report to the network regarding its exit from NTZ 3. This contributes to clarifying the signaling details regarding the mechanism for enabling Aerial UEs to respect the NTZ.

[0135] The aerial UE 1 may use or consider geographic information of the NTZ 3 for cell selection or reselection in the RRC_IDLE or RRC_INACTIVE state. FIG. 25 shows an example of the operation of the aerial UE 1. In step 2501, the aerial UE 1 receives NTZ-related information including geographic information of the NTZ 3 when the aerial UE 1 is in the RRC_IDLE or RRC_INACTIVE state. In step 2502, the aerial UE 1 determines whether the aerial UE 1 is within the NTZ 3. The aerial UE 1 may use GNSS location information to acquire its location. In step 2503, when the aerial UE 1 is within the NTZ 3, the aerial UE 1 excludes cells operating in frequency bands prohibited for use within the NTZ 3 from candidate cells for cell selection or reselection. In other words, when the aerial UE 1 is within the NTZ 3, the aerial UE 1 treats cells operating in frequency bands that are prohibited for use within the NTZ 3 as prohibited cells in cell selection or cell reselection.

[0136] According to the operation shown in Figure 25, the aerial UE 1 can use or take into account the geographical information of the NTZ 3 for cell selection or cell reselection, which contributes to clarifying the details of the operation of the aerial UEs regarding the mechanism for enabling the aerial UEs to respect the NTZ.

[0137] The aerial UE 1 may use or take into account the geographic information of the NTZ 3 to update its flight path information. Figure 26 shows an example of the operation of the aerial UE 1. In step 2601, the aerial UE 1 receives NTZ-related information including the geographic information of the NTZ 3. The aerial UE 1 may receive the NTZ-related information when the aerial UE 1 is in the RRC_IDLE or RRC_INACTIVE state. Alternatively, the aerial UE 1 may receive the NTZ-related information via a UE-dedicated RRC message (e.g., an RRCReconfiguration message) when the aerial UE 1 is in the RRC_CONNECTED state.

[0138] In step 2602, aerial UE 1 updates its flight path information based on the NTZ-related information. For example, aerial UE 1 may update its flight path information to avoid NTZ 3. The flight path information includes multiple waypoints defined as three-dimensional positions.

[0139] The aerial UE 1 may report updated flight path information to the network (e.g., RAN node 2). The trigger condition for reporting the updated flight path information is not particularly limited. For example, the trigger condition may be an update of flight path information. The trigger condition may be a threshold-based trigger for the number of updated or changed waypoints. Alternatively, the trigger condition may be a timer-based periodic trigger. Alternatively, the trigger condition may be a distance-based event trigger.

[0140] According to the operation shown in Figure 25, Aerial UE 1 can use or take into account the geographic information of NTZ 3 to update its flight path, which helps clarify the details of Aerial UE operation regarding the mechanism to enable Aerial UEs to respect NTZs.

[0141] The aerial UE 1 may use or take into account the geographic information of the NTZ 3 to send a flight path update notification to the network (e.g., RAN node 2). Note that the flight path update notification in this specification may be a notification that flight path information is available. In other words, the flight path update notification may not involve updating the flight path information. Therefore, the flight path update notification may be rephrased as a flight path availability notification.

[0142] FIG. 27 shows an example of the operation of the aerial UE 1 and the RAN node 2. In step 2701, the aerial UE 1 receives geographical information for defining the geographical range of the NTZ 3 from the serving RAN node 2. The aerial UE 1 may receive the geographical information via broadcast in the serving cell 21 when the aerial UE 1 is in the RRC_IDLE or RRC_INACTIVE state. Alternatively, the aerial UE 1 may receive the geographical information via a UE-dedicated RRC message (e.g., an RRCReconfiguration message) when the aerial UE 1 is in the RRC_CONNECTED state. However, step 2701 may be omitted. Specifically, the aerial UE 1 may receive the geographical information of the NTZ 3 from another RAN node 2 before starting communication with the RAN node 2 shown in FIG. 27.

[0143] In step 2702, the serving RAN node 2 transmits a flight path update notification trigger configuration based on the distance to the NTZ 3 to the aerial UE 1. In other words, the serving RAN node 2 configures a condition or event based on the distance to the NTZ 3 for triggering the transmission of a flight path update notification in the aerial UE 1. This condition may be that the distance between the aerial UE 1 and the NTZ 3 (or the reference position of the NTZ 3) is below a threshold. Alternatively, this condition may be that the distance between the aerial UE 1 and the NTZ 3 (or the reference position of the NTZ 3) is above a threshold. The serving RAN node 2 may broadcast the flight path update notification trigger configuration in the cell 21 via system information (e.g., SIB). Alternatively, the serving RAN node 2 may configure the flight path update notification trigger in the aerial UE 1 via a UE-dedicated RRC message (e.g., RRCReconfiguration message).

[0144] In step 2703, the Aerial UE 1 detects the establishment of the set trigger condition. In step 2704, in response to the establishment of the trigger condition, the Aerial UE 1 sends a flight path update notification to the serving RAN node 2.

[0145] The flight path update notification (or flight path availability notification) can be sent via various RRC messages. For example, the aerial UE 1 can indicate whether the flight path update notification (or flight path availability notification) is required to the serving RAN node 2 via an RRCReconfigurationComplete, RRCReestablishmentComplete, RRCResumeComplete, or RRCSetupComplete message. Additionally or alternatively, the flight path update notification (or flight path availability notification) can be sent using the UE Assistance Information procedure. Specifically, the aerial UE 1 in the RRC_CONNECTED state can send a flight path update notification or indication to the network in a UEAssistanceInformation message based on configuration by the serving RAN node 2.

[0146] As shown in step 2705, in response to receiving the flight path update notification (or flight path available notification), the serving RAN node 2 may request the Aerial UE 1 to report the flypath information. The serving RAN node 2 may request this using a UEInformationRequest message. In response to this request, in step 2706, the Aerial UE 1 may transmit the flight path information to the network. The Aerial UE 1 may send the flight path information to the network using a UEInformationResponse message. The flight information may only be a delta report (i.e., the difference from the previous report).

[0147] According to the operation shown in Figure 27, the Aerial UE 1 can use or take into account the geographic information of the NTZ 3 to trigger the transmission of a flight path update notification (or flight path availability notification), which contributes to clarifying the details of the Aerial UE's operation regarding the mechanism for enabling the Aerial UE to respect the NTZ.

[0148] Next, exemplary configurations of an aerial UE 1 and a RAN node 2 related to the above-described embodiments will be described. FIG. 19 is a block diagram showing an exemplary configuration of an aerial UE 1. An RF transceiver 2801 performs analog RF signal processing for communication with RAN nodes, including the RAN node 2. The RF transceiver 2801 may include multiple transceivers. The analog RF signal processing performed by the RF transceiver 2801 includes frequency up-conversion, frequency down-conversion, and amplification. The RF transceiver 2801 is coupled to an antenna array 2802 and a baseband processor 2803. The RF transceiver 2801 receives modulation symbol data (or orthogonal frequency-division multiplexing (OFDM) symbol data) from the baseband processor 2803, generates a transmit RF signal, and provides the transmit RF signal to the antenna array 2802. The RF transceiver 2801 also generates a baseband receive signal based on the receive RF signal received by the antenna array 2802 and provides the baseband receive signal to the baseband processor 2803. The RF transceiver 2801 may include an analog beamformer circuit for beamforming, which may include, for example, multiple phase shifters and multiple power amplifiers.

[0149] The baseband processor 2803 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communications. Digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) transmission format (transmission frame) generation / decomposition, (d) transmission path coding / decoding, (e) modulation (symbol mapping) / demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) using Inverse Fast Fourier Transform (IFFT). Meanwhile, control plane processing includes communication management for Layer 1 (e.g., transmit power control), Layer 2 (e.g., radio resource management and hybrid automatic repeat request (HARQ) processing), and Layer 3 (e.g., signaling related to attachment, mobility, and call management).

[0150] For example, the digital baseband signal processing by the baseband processor 2803 may include signal processing of a Service Data Adaptation Protocol (SDAP) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a Physical (PHY) layer. Also, the control plane processing by the baseband processor 2803 may include processing of a Non-Access Stratum (NAS) protocol, an RRC protocol, MAC CEs, and Downlink Control Information (DCI).

[0151] The baseband processor 2803 may perform Multiple Input Multiple Output (MIMO) encoding and precoding for beamforming.

[0152] The baseband processor 2803 may include a modem processor (e.g., a Digital Signal Processor (DSP)) that performs digital baseband signal processing and a protocol stack processor (e.g., a Central Processing Unit (CPU) or a Micro Processing Unit (MPU)) that performs control plane processing. In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 2804, which will be described later.

[0153] The application processor 2804 is also referred to as a CPU, MPU, microprocessor, or processor core. The application processor 2804 may include multiple processors (multiple processor cores). The application processor 2804 executes a system software program (operating system (OS)) and various application programs (e.g., a call application, a web browser, a mailer, a camera operation application, and a music playback application) read from the memory 2806 or a memory not shown, thereby realizing various functions of the Aerial UE 1.

[0154] In some implementations, the baseband processor 2803 and the application processor 2804 may be integrated on a single chip, as shown by the dashed line (2805) in Figure 28. In other words, the baseband processor 2803 and the application processor 2804 may be implemented as a single System on Chip (SoC) device 2805. An SoC device is sometimes called a system Large Scale Integration (LSI) or chipset.

[0155] The memory 2806 is volatile memory, nonvolatile memory, or a combination thereof. The memory 2806 may include multiple physically independent memory devices. Volatile memory is, for example, static random access memory (SRAM), dynamic RAM (DRAM), or a combination thereof. Nonvolatile memory is mask read only memory (MROM), electrically erasable programmable ROM (EEPROM), flash memory, a hard disk drive, or any combination thereof. For example, the memory 2806 may include an external memory device accessible from the baseband processor 2803, the application processor 2804, and the SoC 2805. The memory 2806 may also include an internal memory device integrated within the baseband processor 2803, the application processor 2804, or the SoC 2805. Furthermore, the memory 2806 may include memory within a Universal Integrated Circuit Card (UICC).

[0156] The memory 2806 may store one or more software modules (computer programs) 2807 including instructions and data for performing the processes of the aerial UE 1 described in the above embodiments. In some implementations, the baseband processor 2803 or the application processor 2804 may be configured to read and execute the software modules 2807 from the memory 2806 to perform the processes of the aerial UE 1 described in the above embodiments using the drawings.

[0157] The control plane processing and operations performed by UE 1 described in the above embodiment may be realized by elements other than the RF transceiver 2801 and the antenna array 2802, namely, at least one of the baseband processor 2803 and the application processor 2804, and the memory 2806 storing the software module 2807.

[0158] FIG. 29 is a block diagram showing an example configuration of a RAN node 2 according to the above embodiment. Referring to FIG. 29, the RAN node 2 includes an RF transceiver 2901, a network interface 2903, a processor 2904, and a memory 2905. The RF transceiver 2901 performs analog RF signal processing for communication with UEs, including the aerial UE 1. The RF transceiver 2901 may include multiple transceivers. The RF transceiver 2901 is coupled to an antenna array 2902 and a processor 2904. The RF transceiver 2901 receives modulation symbol data from the processor 2904, generates a transmit RF signal, and provides the transmit RF signal to the antenna array 2902. The RF transceiver 2901 also generates a baseband receive signal based on the receive RF signal received by the antenna array 2902 and provides the baseband receive signal to the processor 2904. The RF transceiver 2901 may include an analog beamformer circuit for beamforming. The analog beamformer circuitry includes, for example, multiple phase shifters and multiple power amplifiers.

[0159] The network interface 2903 is used to communicate with network nodes (e.g., other RAN nodes, and control and forwarding nodes of the core network), and may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0160] The processor 2904 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. The processor 2904 may include multiple processors. For example, the processor 2904 may include a modem processor (e.g., DSP) that performs digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) that performs control plane processing.

[0161] For example, digital baseband signal processing by the processor 2904 may include signal processing for SDAP, PDCP, Radio RLC, MAC, and PHY layers, and control plane processing by the processor 2904 may include processing of NAS messages, RRC messages, MAC CEs, and DCIs.

[0162] The processor 2904 may include a digital beamformer module for beamforming, which may include a MIMO encoder and precoder.

[0163] The memory 2905 is configured by a combination of volatile memory and non-volatile memory. The volatile memory is, for example, SRAM or DRAM, or a combination thereof. The non-volatile memory is, for example, MROM, EEPROM, flash memory, or a hard disk drive, or any combination thereof. The memory 2905 may include storage located remotely from the processor 2904. In this case, the processor 2904 may access the memory 2905 via the network interface 2903 or an I / O interface (not shown).

[0164] The memory 2905 may store one or more software modules (computer programs) 2906 including instructions and data for performing the processes of the RAN node 2 described in the above embodiments. In some implementations, the processor 2904 may be configured to read and execute the software modules 2906 from the memory 2905 to perform the processes of the RAN node 2 described in the above embodiments.

[0165] If the RAN node 2 is a CU (e.g., eNB-CU or gNB-CU) or a CU-CP, the RAN node 2 may not include the RF transceiver 2901 (and antenna array 2902) and the LP-WUS transmitter 1810.

[0166] As described with reference to Figures 28 and 29, each of the processors included in the aerial UE 1 and the RAN node 2 according to the above-described embodiments can execute one or more programs including instructions for causing the computer to perform the algorithms described with reference to the drawings. The programs include instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The programs may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disk (DVD), Blu-ray disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The programs may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0167] The above-described embodiments are merely examples of application of the technical ideas obtained by the inventors of the present invention. In other words, the technical ideas are not limited to the above-described embodiments, and various modifications are possible.

[0168] For example, some or all of the above embodiments may also be described as, but are not limited to, the following appendices. Some or all of the elements (e.g., configurations and functions) described in appendices directed to apparatuses (e.g., aerial UEs or RAN nodes) may naturally also be described as appendices directed to methods and programs. For example, some or all of the elements described in appendices 2-10, which are dependent on appendices 1-12, may also be described as appendices dependent on appendices 11 and 12, due to the same dependency relationship as appendices 2-10. Some or all of the elements described in any appendice may be applied to various hardware, software, recording means for recording software, systems, and methods.

[0169] (Supplementary Note 1) An aerial User Equipment (UE) comprising: means for receiving system information via broadcast in a first cell; means for treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes first information indicating whether the first cell is prohibited for aerial UEs and the first information indicates that the first cell is prohibited for aerial UEs; means for not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes the first information and the first information indicates that the first cell is not prohibited for aerial UEs; and means for not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information does not include the first information. (Supplementary Note 2) The aerial UE according to Supplementary Note 1, wherein the first cell is a cell that is included in or partially overlaps with a no-transmit zone (NTZ) for aerial UEs and whose uplink frequency is included in a frequency band prohibited by the NTZ. (Supplementary Note 3) The aerial UE according to Supplementary Note 2, wherein the NTZ is a geographical area in which transmission of aerial UEs is not permitted in one or more specific frequency bands. (Supplementary Note 4) The aerial UE according to any one of Supplements 1 to 3, wherein the first information applies to all Public Land Mobile Networks (PLMNs) and Non-Public Networks (NPNs) associated with the first cell. (Supplementary Note 5) The aerial UE according to any one of Supplements 1 to 4, wherein the system information is System Information Block type 1 (SIB1). (Supplementary Note 6) The aerial UE according to any one of Supplementary Notes 1 to 5, further comprising: means for receiving, in the first cell, an excluded cell list specific to the aerial UEs, wherein the excluded cell list indicates one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs.(Supplementary Note 7) The aerial UE of Supplementary Note 6, wherein the means for receiving the excluded cell list is adapted to receive the excluded cell list via SIB type 3 (SIB3) or SIB type 4 (SIB4). (Supplementary Note 8) The aerial UE of Supplementary Note 2 or 3, further comprising: means for receiving, in the first cell, geographic information for defining a geographical extent of the NTZ. (Supplementary Note 9) The aerial UE of Supplementary Note 8, wherein the geographical information includes latitude and longitude information for defining a location and extent of the geographical extent. (Supplementary Note 10) The aerial UE of any one of Supplements 2, 3, 7, and 8, further comprising: means for receiving, in the first cell, information indicating one or more frequency bands in which aerial UEs are not allowed to transmit in the NTZ. (Supplementary Note 11) A method performed by aerial User Equipment (UE), comprising: receiving system information via broadcast in a first cell; treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes first information indicating whether the first cell is barred for aerial UEs and the first information indicates that the first cell is barred for aerial UEs; not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes the first information and the first information indicates that the first cell is not barred for aerial UEs; and not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information does not include the first information.(Supplementary Note 12) A program for causing a computer to perform a method for aerial user equipment (UE), the method comprising: receiving system information via broadcast in a first cell; treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes first information indicating whether the first cell is barred for aerial UEs and the first information indicates that the first cell is barred for aerial UEs; not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes the first information and the first information indicates that the first cell is not barred for aerial UEs; and not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information does not include the first information. (Supplementary Note 13) An aerial user equipment (UE), comprising: means for receiving, via broadcast, in a first cell, first information indicating that the first cell belongs to or includes a prohibited transmission zone (NTZ) for aerial UEs, that uplink transmission in the first cell is not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 14) The aerial UE of Supplementary Note 13, wherein the NTZ is a geographical area in which aerial UEs are not permitted to transmit in one or more specific frequency bands. (Supplementary Note 15) The aerial UE of Supplementary Note 13 or 14, wherein the first information applies to all Public Land Mobile Networks (PLMNs) and Non-Public Networks (NPNs) associated with the first cell. (Supplementary Note 16) The aerial UE according to any one of Supplementary Notes 13 to 15, wherein the first information is included in a System Information Block type 1 (SIB1) broadcast in the first cell.(Supplementary Note 17) The aerial UE according to any one of Supplements 13 to 16, wherein the first cell is a cell that is included in or partially overlaps with the NTZ and whose uplink frequency is included in a frequency band prohibited by the NTZ. (Supplementary Note 18) The aerial UE according to any one of Supplements 13 to 17, further comprising: means for receiving, in the first cell, a neighboring cell list specific to aerial UEs, wherein each of the one or more cells included in the neighboring cell list is a cell that belongs to or includes an NTZ, a cell from which uplink transmission is not permitted to aerial UEs, or a cell that provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 19) The aerial UE according to Supplementary Note 18, wherein the means for receiving the neighboring cell list is adapted to receive the neighboring cell list via system information broadcasted in the first cell. (Supplementary Note 20) The aerial UE according to Supplementary Note 18 or 19, further comprising: means for excluding a cell included in the neighbor cell list from candidate cells for cell reselection. (Supplementary Note 21) The aerial UE according to any one of Supplements 18 to 20, further comprising: means for excluding a cell included in the neighbor cell list from candidate cells for primary cell of carrier aggregation. (Supplementary Note 22) The aerial UE according to any one of Supplements 13 to 21, further comprising: means for receiving, in the first cell, geographic information for defining a geographical range of the NTZ. (Supplementary Note 23) The aerial UE according to Supplementary Note 22, wherein the geographical information includes latitude and longitude information for defining a location and range of the geographical range. (Supplementary Note 24) The aerial UE according to any one of Supplements 13 to 23, further comprising: means for receiving, in the first cell, information indicating one or more frequency bands in which aerial UEs are not allowed to transmit in the NTZ.(Supplementary Note 25) A Radio Access Network (RAN) node comprising: means for broadcasting, in a first cell, first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but not uplink communication services to aerial UEs. (Supplementary Note 26) The RAN node of Supplementary Note 25, wherein the NTZ is a geographical area in which transmissions for aerial UEs are not permitted in one or more specific frequency bands. (Supplementary Note 27) The RAN node of Supplementary Note 25 or 26, wherein the first information applies to all Public Land Mobile Networks (PLMNs) and Non-Public Networks (NPNs) associated with the first cell. (Supplementary Note 28) The RAN node according to any one of Supplements 25 to 27, wherein the first information is included in a System Information Block type 1 (SIB1) broadcast in the first cell. (Supplementary Note 29) The RAN node according to any one of Supplements 25 to 28, wherein the first cell is a cell that is included in or partially overlaps with the NTZ and whose uplink frequency is included in a frequency band prohibited by the NTZ. (Supplementary Note 30) The RAN node according to any one of Supplements 25 to 29, further comprising means for transmitting in the first cell a neighboring cell list specific to aerial UEs, wherein each of one or more cells included in the neighboring cell list is a cell that belongs to or includes an NTZ, a cell from which uplink transmissions are not permitted for aerial UEs, or a cell that provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 31) The RAN node according to Supplementary Note 30, wherein the means for transmitting the neighbor cell list is adapted to transmit the neighbor cell list via system information broadcast in the first cell.(Supplementary Note 32) The RAN node of any one of Supplements 25 to 31, further comprising: means for transmitting, in the first cell, geographic information for defining a geographical extent of the NTZ. (Supplementary Note 33) The RAN node of Supplementary Note 32, wherein the geographical information includes latitude and longitude information for defining a location and extent of the geographical extent. (Supplementary Note 34) The RAN node of any one of Supplements 25 to 33, further comprising: means for transmitting, in the first cell, information indicating one or more frequency bands in which aerial UEs are not allowed to transmit in the NTZ. (Supplementary Note 35) The RAN node of any one of Supplements 25 to 34, further comprising: means for transmitting, to a neighboring RAN node, information indicating whether the first cell at least partially overlaps with the NTZ, and for receiving from the neighboring RAN node information indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ. (Supplementary Note 36) The RAN node according to any one of Supplements 25 to 35, comprising a central unit and distributed units, wherein the central unit is configured to send information indicating whether a cell provided by the distributed unit at least partially overlaps with the NTZ to the distributed units. (Supplementary Note 37) The RAN node according to any one of Supplementary Notes 25 to 35, comprising a central unit and distributed units, wherein the distributed units are configured to send information indicating whether a cell provided by the distributed unit at least partially overlaps with the NTZ to the central unit. (Supplementary Note 38) A method performed by an aerial user equipment (UE), comprising receiving, via broadcast, at a first cell, first information indicating that the first cell belongs to or includes a no transmission zone (NTZ) for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.(Supplementary Note 39) A method performed by a Radio Access Network (RAN) node, comprising: broadcasting, in a first cell, first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmission in the first cell is not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 40) A program for causing a computer to perform a method for aerial User Equipment (UE), the method comprising receiving, via broadcast, in a first cell, first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmission in the first cell is not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 41) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising: broadcasting, in a first cell, first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmission in the first cell is not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 42) An aerial User Equipment (UE), comprising: means for receiving, in a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs.(Supplementary Note 43) The aerial UE according to Supplementary Note 42, wherein the receiving means is adapted to receive the excluded cell list via SIB type 3 (SIB3) or SIB type 4 (SIB4). (Supplementary Note 44) The aerial UE according to Supplementary Note 42 or 43, further comprising: means for excluding one or more cells included in the excluded cell list from candidate cells for cell reselection. (Supplementary Note 45) The aerial UE according to any one of Supplements 42 to 44, further comprising: means for excluding cells included in the excluded cell list from candidate primary cells for carrier aggregation. (Supplementary Note 46) The aerial UE according to any one of Supplements 42 to 45, wherein each of the one or more cells included in the excluded cell list is a cell that is included in or partially overlaps with a no-transmit zone (NTZ) for aerial UEs and whose uplink frequency is included in a frequency band prohibited by the NTZ. (Supplementary Note 47) The aerial UE of Supplementary Note 46, wherein the NTZ is a geographical area in which aerial UEs are not allowed to transmit in one or more specific frequency bands. (Supplementary Note 48) A Radio Access Network (RAN) node, comprising: means for transmitting, in a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UE. (Supplementary Note 49) The RAN node of Supplementary Note 48, further comprising means for including in the excluded cell list one or more cells that are included in or partially overlapping a no-transmit zone (NTZ) for aerial UEs and whose uplink frequencies are included in a frequency band prohibited by the NTZ. (Supplementary Note 50) The RAN node of Supplementary Note 48 or 49, wherein the NTZ is a geographical area in which aerial UEs are not allowed to transmit in one or more specific frequency bands.(Supplementary Note 51) The RAN node of any one of Supplementary Notes 48 to 50, wherein the transmitting means is adapted to transmit the excluded cell list via SIB type 3 (SIB3) or SIB type 4 (SIB4). (Supplementary Note 52) A method performed by an aerial User Equipment (UE), comprising receiving, at a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs. (Supplementary Note 53) A method performed by a Radio Access Network (RAN) node, comprising transmitting, at a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs. (Supplementary Note 54) A program for causing a computer to perform a method for aerial user equipment (UE), the method comprising receiving, at a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs. (Supplementary Note 55) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising transmitting, at a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs. (Supplementary Note 56) An aerial user equipment (UE), comprising: means for receiving, at a first cell, a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell belonging to or including a prohibited transmission zone (NTZ) for the aerial UEs, a cell from which uplink transmission is not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.(Supplementary Note 57) The aerial UE of Supplementary Note 56, wherein the receiving means is adapted to receive the neighbor cell list via system information broadcasted in the first cell. (Supplementary Note 58) The aerial UE of Supplementary Note 56 or 57, further comprising: means for excluding one or more cells included in the neighbor cell list from candidate cells for cell reselection. (Supplementary Note 59) The aerial UE of any one of Supplements 56 to 58, further comprising: means for excluding cells included in the neighbor cell list from candidate primary cells for carrier aggregation. (Supplementary Note 60) The aerial UE of any one of Supplements 56 to 59, wherein the NTZ is a geographical area in which aerial UEs are not allowed to transmit in one or more specific frequency bands. (Supplementary Note 61) A Radio Access Network (RAN) node comprising: means for transmitting, in a first cell, a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell belonging to or including a No Transmission Zone (NTZ) for the aerial UEs, a cell from which uplink transmissions are not permitted to the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs. (Supplementary Note 62) The RAN node of Supplementary Note 61, further comprising means for including in the neighbor cell list one or more cells that are included in or partially overlapping with the NTZ and whose uplink frequencies are included in a frequency band prohibited by the NTZ. (Supplementary Note 63) The RAN node of Supplementary Note 61 or 62, wherein the NTZ is a geographical area in which transmissions for aerial UEs are not permitted in one or more specific frequency bands. (Supplementary Note 64) The RAN node according to any one of Supplementary Notes 61 to 63, wherein the transmitting means is adapted to transmit the neighbor cell list via system information broadcast in the first cell.(Supplementary Note 65) A method performed by aerial user equipment (UE), comprising receiving, at a first cell, a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell belonging to or including a prohibited transmission zone (NTZ) for aerial UEs, a cell from which uplink transmission is not permitted for aerial UEs, or a cell that provides downlink communication service to aerial UEs but not uplink communication service to aerial UEs. (Supplementary Note 66) A method performed by a radio access network (RAN) node, comprising transmitting, at a first cell, a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell belonging to or including a prohibited transmission zone (NTZ) for aerial UEs, a cell from which uplink transmission is not permitted for aerial UEs, or a cell that provides downlink communication service to aerial UEs but not uplink communication service to aerial UEs. (Supplementary Note 67) A program for causing a computer to perform a method for aerial user equipment (UE), the method comprising receiving, at a first cell, a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a prohibited transmission zone (NTZ) for the aerial UEs, a cell from which uplink transmission is not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.(Supplementary Note 68) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising: transmitting, at a first cell, a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a prohibited transmission zone (NTZ) for aerial UEs, a cell from which uplink transmissions are not permitted for aerial UEs, or a cell that provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 69) A Radio Access Network (RAN) node, comprising: means for transmitting, to a neighboring RAN node, first information indicating whether a first cell of the RAN node at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs, and receiving, from the neighboring RAN node, second information indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ. (Supplementary Note 70) The RAN node of Supplementary Note 69, further comprising means for transmitting third information to the neighboring RAN node, the third information indicating whether each of one or more neighboring cells of the first cell at least partially overlaps with the NTZ. (Supplementary Note 71) The RAN node of Supplementary Note 69 or 70, wherein the means is adapted to transmit the first information to the neighboring RAN node via an XN SETUP REQUEST, an XN SETUP RESPONSE, an NG-RAN NODE CONFIGURATION UPDATE, an NG-RAN NODE CONFIGURATION UPDATE ACKNOWLEDGE, or an ACCESS AND MOBILITY INDICATION message. (Supplementary Note 72) The RAN node of any one of Supplements 69 to 71, further comprising means for determining a target cell for handover of an aerial UE taking into account the second information. (Supplementary Note 73) The RAN node of Supplementary Note 72, wherein the determining means is adapted to select a cell that does not even partially overlap with the NTZ as the target cell.(Supplementary Note 74) The RAN node according to Supplementary Note 72 or 73, further comprising: means for generating an excluded cell list specific to aerial UEs taking into account the second information; and means for broadcasting the excluded cell list in the first cell, wherein the excluded cell list indicates one or more neighboring cells to be excluded from candidate cells for cell reselection by aerial UEs. (Supplementary Note 76) The RAN node according to Supplementary Note 75, further comprising: means for generating an excluded cell list specific to aerial UEs taking into account the second information; and means for broadcasting the excluded cell list in the first cell, wherein the excluded cell list indicates one or more neighboring cells to be excluded from candidate cells for cell reselection by aerial UEs. (Supplementary Note 76) The RAN node according to Supplementary Note 75, wherein the generating means is adapted to include in the excluded cell list cells that at least partially overlap with the NTZ and whose uplink frequencies are included in a frequency band prohibited by the NTZ. (Supplementary Note 77) The RAN node according to any one of Supplementary Notes 69 to 76, further comprising: means for generating a neighbor cell list specific to aerial UEs taking into consideration the second information; and means for broadcasting the neighbor cell list in the first cell, wherein each of one or more cells included in the neighbor cell list is a cell belonging to or including the NTZ, a cell from which uplink transmission is not permitted to aerial UEs, or a cell that provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs. (Supplementary Note 78) The RAN node according to Supplementary Note 77, wherein the neighbor cell list causes aerial UEs to exclude one or more cells included in the neighbor cell list from candidate cells for cell reselection. (Supplementary Note 79) The RAN node according to Supplementary Note 77 or 78, wherein the neighbor cell list causes aerial UEs to exclude cells included in the neighbor cell list from candidate primary cells for carrier aggregation.(Supplementary Note 80) The RAN node of any one of Supplements 69 to 79, wherein the NTZ is a geographical area in which transmission of aerial UEs is not permitted in one or more specific frequency bands. (Supplementary Note 81) A method performed by a Radio Access Network (RAN) node, comprising: transmitting to a neighboring RAN node first information indicating whether a first cell of the RAN node at least partially overlaps with a transmission prohibited zone (NTZ) for aerial UEs, and receiving from the neighboring RAN node second information indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ. (Supplementary Note 82) A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising: transmitting to a neighboring RAN node first information indicating whether a first cell of the RAN node at least partially overlaps with a transmission prohibited zone (NTZ) for aerial UEs, and receiving from the neighboring RAN node second information indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ. (Supplementary Note 83) A central unit of a Radio Access Network (RAN) node, comprising: means for transmitting, to a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs. (Supplementary Note 84) The central unit of Supplementary Note 83, wherein the transmitting means is adapted to transmit the first information via an F1 SETUP RESPONSE, a GNB-DU CONFIGURATION UPDATE ACKNOWLEDGE, or a GNB-CU CONFIGURATION UPDATE message. (Supplementary Note 85) The central unit of Supplementary Note 83 or 84, wherein the transmitting means is adapted to transmit, to the first distributed unit, second information indicating whether a second cell provided by a second distributed unit other than the first distributed unit at least partially overlaps with the NTZ.(Supplementary Note 86) A distributed unit of a Radio Access Network (RAN) node, comprising: means for receiving from a central unit of the RAN node first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs. (Supplementary Note 87) The distributed unit of Supplementary Note 86, wherein the receiving means is adapted to receive the first information via an F1 SETUP RESPONSE, a GNB-DU CONFIGURATION UPDATE ACKNOWLEDGE, or a GNB-CU CONFIGURATION UPDATE message. (Supplementary Note 88) The distributed unit of Supplementary Note 86 or 87, wherein the receiving means is further adapted to receive from the central unit second information indicating whether a second cell provided by another distributed unit at least partially overlaps with the NTZ. (Supplementary Note 89) A method performed by a central unit of a Radio Access Network (RAN) node, comprising transmitting, to a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs. (Supplementary Note 90) A method performed by a distributed unit of a Radio Access Network (RAN) node, comprising receiving, from a central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs. (Supplementary Note 91) A program for a central unit of a Radio Access Network (RAN) node, for causing a computer to perform a method, the method comprising transmitting, to a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs.(Supplementary Note 92) A program for causing a computer to perform a method for a distributed unit of a Radio Access Network (RAN) node, the method comprising receiving, from a central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs. (Supplementary Note 93) A central unit of a Radio Access Network (RAN) node, the central unit comprising: means for receiving, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs. (Supplementary Note 94) The central unit of Supplementary Note 93, wherein the means for receiving is adapted to receive the first information via an F1 SETUP REQUEST or a GNB-DU CONFIGURATION UPDATE message. (Supplementary Note 95) The central unit of Supplementary Note 93 or 94, further comprising means for transmitting, to a second distributed unit other than the first distributed unit, second information indicating whether the first cell of the first distributed unit at least partially overlaps with the NTZ. (Supplementary Note 96) A distributed unit of a Radio Access Network (RAN) node, comprising means for transmitting, to the central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs. (Supplementary Note 97) The distributed unit of Supplementary Note 96, wherein the means for transmitting is adapted to transmit the first information via an F1 SETUP REQUEST or a GNB-DU CONFIGURATION UPDATE message. (Supplementary Note 98) The distributed unit of Supplementary Note 96 or 97, further comprising means for receiving, from the central unit, second information indicating whether a second cell provided by another distributed unit at least partially overlaps with the NTZ.(Supplementary Note 99) A method performed by a central unit of a Radio Access Network (RAN) node, comprising receiving, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs. (Supplementary Note 100) A method performed by a distributed unit of a Radio Access Network (RAN) node, comprising transmitting, to the central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs. (Supplementary Note 101) A program for a central unit of a Radio Access Network (RAN) node, for causing a computer to perform a method, the method comprising receiving, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a prohibited transmission zone (NTZ) for aerial UEs. (Supplementary Note 102) A program for causing a computer to perform a method for a distributed unit of a Radio Access Network (RAN) node, the method comprising transmitting, to a central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

[0170] This application claims priority based on Japanese Patent Application No. 2023-139932, filed on August 30, 2023, the disclosure of which is incorporated herein in its entirety.

[0171] 1 Aerial UE 2, 2A to 2G RAN node 21, 21A to 21G Cell 3 No Transmission Zone (NTZ) 22 Central Unit (CU) 23, 23A to 23C Distributed Unit (DU)

Claims

1. An aerial User Equipment (UE), comprising: means for receiving system information via broadcast in a first cell; means for treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes first information indicating whether the first cell is prohibited for aerial UEs and the first information indicates that the first cell is prohibited for aerial UEs; means for not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes the first information and the first information indicates that the first cell is not prohibited for aerial UEs; and means for not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information does not include the first information.

2. The aerial UE of claim 1, wherein the first cell is a cell that is included in or partially overlaps a no-transmit zone (NTZ) for aerial UEs and whose uplink frequency is included in a frequency band prohibited by the NTZ.

3. The aerial UE of claim 2, wherein the NTZ is a geographic area in which aerial UEs are not permitted to transmit in one or more particular frequency bands.

4. The aerial UE according to any one of claims 1 to 3, wherein the system information is System Information Block type 1 (SIB1).

5. The aerial UE according to any one of claims 1 to 4, further comprising means for receiving, in the first cell, an excluded cell list specific to the aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded from candidate cells for cell reselection by the aerial UEs.

6. The Aerial UE according to claim 2 or 3, further comprising means for receiving, in the first cell, geographic information for defining a geographical extent of the NTZ.

7. The Aerial UE of any one of claims 2, 3 and 6, further comprising means for receiving, in the first cell, information indicating one or more frequency bands in which Aerial UEs are not permitted to transmit in the NTZ.

8. A method performed by an aerial user equipment (UE), comprising: receiving system information via broadcast in a first cell; if the system information includes first information indicating whether the first cell is forbidden to aerial UEs, and if the first information indicates that the first cell is forbidden to aerial UEs, treating the first cell as a forbidden cell in cell selection or cell reselection; if the system information includes the first information and the first information indicates that the first cell is not forbidden to aerial UEs, not treating the first cell as a forbidden cell in cell selection or cell reselection; and if the system information does not include the first information, not treating the first cell as a forbidden cell in cell selection or cell reselection.

9. A program for causing a computer to perform a method for aerial user equipment (UE), the method comprising: receiving system information via broadcast in a first cell; treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes first information indicating whether the first cell is prohibited for aerial UEs, and if the first information indicates that the first cell is prohibited for aerial UEs; not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information includes the first information and the first information indicates that the first cell is not prohibited for aerial UEs; and not treating the first cell as a prohibited cell in cell selection or cell reselection if the system information does not include the first information.

10. An aerial user equipment (UE), comprising: means for receiving, via broadcast, in a first cell, first information indicating that the first cell belongs to or includes a prohibited transmission zone (NTZ) for aerial UEs, that uplink transmission in the first cell is not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

11. The aerial UE of claim 10, wherein the NTZ is a geographic area in which aerial UEs are not permitted to transmit in one or more particular frequency bands.

12. The aerial UE according to claim 10 or 11, wherein the first information is included in a System Information Block type 1 (SIB1) broadcast in the first cell.

13. An aerial UE as claimed in any one of claims 10 to 12, further comprising means for receiving in the first cell a neighbouring cell list specific to the aerial UEs, wherein each of the one or more cells included in the neighbouring cell list is a cell belonging to or including an NTZ, a cell in which uplink transmission is not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.

14. The Aerial UE according to any one of claims 10 to 13, further comprising means for receiving, in the first cell, geographic information for defining a geographical extent of the NTZ.

15. An aerial UE as claimed in any one of claims 10 to 14, further comprising means for receiving, in the first cell, information indicating one or more frequency bands in which transmission of aerial UEs is not permitted in the NTZ.

16. A Radio Access Network (RAN) node comprising: means for broadcasting, in a first cell, first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

17. A method performed by an aerial user equipment (UE), comprising receiving, via broadcast, in a first cell, first information indicating that the first cell belongs to or includes a prohibited transmission zone (NTZ) for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

18. A method performed by a Radio Access Network (RAN) node, comprising: broadcasting, in a first cell, first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

19. A program for causing a computer to execute a method for aerial user equipment (UE), the method comprising receiving, via broadcast, in a first cell, first information indicating that the first cell belongs to or includes a prohibited transmission zone (NTZ) for aerial UEs, that uplink transmission in the first cell is not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

20. A program for causing a computer to execute a method for a Radio Access Network (RAN) node, the method comprising: broadcasting, in a first cell, first information indicating that the first cell belongs to or includes a No Transmission Zone (NTZ) for aerial UEs, that uplink transmissions in the first cell are not permitted for aerial UEs, or that the first cell provides downlink communication services to aerial UEs but does not provide uplink communication services to aerial UEs.

21. An aerial User Equipment (UE), comprising: means for receiving, at a first cell, an excluded cell list specific to the aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UEs.

22. The aerial UE of claim 21, wherein each of the one or more cells included in the excluded cell list is a cell that is included in or overlaps a no-transmit zone (NTZ) for aerial UEs and whose uplink frequency is included in a frequency band prohibited by the NTZ.

23. The aerial UE of claim 22, wherein the NTZ is a geographic area in which aerial UEs are not permitted to transmit in one or more particular frequency bands.

24. A Radio Access Network (RAN) node comprising: means for transmitting, in a first cell, an excluded cell list specific to an aerial UE, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UE.

25. A method performed by an aerial User Equipment (UE), comprising receiving at a first cell an excluded cell list specific to the aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UEs.

26. A method performed by a Radio Access Network (RAN) node, comprising: transmitting, in a first cell, an excluded cell list specific to an aerial UE, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UE.

27. A program for causing a computer to perform a method for aerial user equipment (UE), the method comprising receiving, at a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UEs.

28. A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising: transmitting, in a first cell, an excluded cell list specific to aerial UEs, the excluded cell list indicating one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UEs.

29. An aerial User Equipment (UE), comprising: means for receiving, at a first cell, a neighbor cell list specific to the aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a prohibited transmission zone (NTZ) for the aerial UEs, a cell from which uplink transmission is not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.

30. The aerial UE of claim 29, wherein the NTZ is a geographic area in which aerial UEs are not permitted to transmit in one or more particular frequency bands.

31. A Radio Access Network (RAN) node comprising: means for transmitting, in a first cell, a neighbor cell list specific to an aerial UE, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a No Transmission Zone (NTZ) for the aerial UE, a cell for which uplink transmission is not permitted for the aerial UE, or a cell that provides downlink communication services to the aerial UE but does not provide uplink communication services to the aerial UE.

32. The RAN node of claim 31, wherein the NTZ is a geographic area in which transmissions of airborne UEs are not permitted in one or more particular frequency bands.

33. A method performed by an aerial user equipment (UE), comprising: receiving at a first cell a neighbor cell list specific to the aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a prohibited transmission zone (NTZ) for the aerial UEs, a cell from which uplink transmissions are not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.

34. A method performed by a Radio Access Network (RAN) node, comprising: transmitting in a first cell a neighbor cell list specific to an aerial UE, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a No Transmission Zone (NTZ) for the aerial UE, a cell for which uplink transmission is not permitted for the aerial UE, or a cell that provides downlink communication services to the aerial UE but does not provide uplink communication services to the aerial UE.

35. A program for causing a computer to perform a method for aerial user equipment (UE), the method comprising receiving at a first cell a neighbor cell list specific to aerial UEs, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a prohibited transmission zone (NTZ) for the aerial UEs, a cell from which uplink transmission is not permitted for the aerial UEs, or a cell that provides downlink communication services to the aerial UEs but does not provide uplink communication services to the aerial UEs.

36. A program for causing a computer to perform a method for a Radio Access Network (RAN) node, the method comprising: transmitting, at a first cell, a neighbor cell list specific to an aerial UE, wherein each of one or more cells included in the neighbor cell list is a cell that belongs to or includes a No Transmission Zone (NTZ) for the aerial UE, a cell from which uplink transmission is not permitted for the aerial UE, or a cell that provides downlink communication services to the aerial UE but does not provide uplink communication services to the aerial UE.

37. A Radio Access Network (RAN) node comprising: means for transmitting first information to a neighbouring RAN node, the first information indicating whether a first cell of the RAN node at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs; and receiving second information from the neighbouring RAN node, the second information indicating whether a second cell of the neighbouring RAN node at least partially overlaps with the NTZ.

38. The RAN node of claim 37, further comprising: means for determining a target cell for handover of an aerial UE taking into account the second information.

39. The RAN node of claim 38, further comprising: if the target cell cannot be selected, sending a message to the aerial UE to release a Radio Resource Control (RRC) connection of the aerial UE, the message indicating to the aerial UE that the cause of the release of the RRC connection is entry into a NTZ.

40. The RAN node according to any one of claims 37 to 39, further comprising: means for generating an excluded cell list specific to an aerial UE taking into account the second information; and means for broadcasting the excluded cell list in the first cell, wherein the excluded cell list indicates one or more neighboring cells to be excluded as candidate cells for cell reselection by the aerial UEs.

41. The RAN node of claim 40, wherein the generating means is adapted to include in the excluded cell list cells that at least partially overlap with the NTZ and whose uplink frequencies are included in a frequency band prohibited by the NTZ.

42. The RAN node of any one of claims 37 to 41, wherein the NTZ is a geographical area within which transmission of airborne UEs is not permitted in one or more particular frequency bands.

43. A method performed by a Radio Access Network (RAN) node, comprising: transmitting first information to a neighboring RAN node indicating whether a first cell of the RAN node at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs; and receiving second information from the neighboring RAN node indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ.

44. A program for causing a computer to execute a method for a Radio Access Network (RAN) node, the method comprising: transmitting first information to a neighboring RAN node indicating whether a first cell of the RAN node at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs; and receiving second information from the neighboring RAN node indicating whether a second cell of the neighboring RAN node at least partially overlaps with the NTZ.

45. A central unit of a Radio Access Network (RAN) node, comprising: means for transmitting, to a first distributed unit of the RAN node, first information indicative of whether a first cell provided by the first distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

46. ​​A central unit according to claim 45, wherein the transmitting means is adapted to transmit to the first distributed unit second information indicating whether a second cell provided by a second distributed unit other than the first distributed unit at least partially overlaps with the NTZ.

47. A distributed unit of a Radio Access Network (RAN) node, comprising: means for receiving from a central unit of the RAN node first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

48. A method performed by a central unit of a Radio Access Network (RAN) node, comprising: transmitting, to a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

49. A method performed by a distributed unit of a Radio Access Network (RAN) node, comprising receiving first information from a central unit of the RAN node indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

50. A program for causing a computer to perform a method for a central unit of a Radio Access Network (RAN) node, the method comprising: transmitting, to a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

51. A program for causing a computer to perform a method for a distributed unit of a Radio Access Network (RAN) node, the method comprising receiving, from a central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

52. A central unit of a Radio Access Network (RAN) node, comprising: means for receiving, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

53. A distributed unit of a Radio Access Network (RAN) node, comprising: means for transmitting first information to a central unit of the RAN node, the first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

54. A method performed by a central unit of a Radio Access Network (RAN) node, comprising receiving, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

55. A method performed by a distributed unit of a Radio Access Network (RAN) node, comprising: transmitting first information to a central unit of the RAN node indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

56. A program for causing a computer to perform a method for a central unit of a Radio Access Network (RAN) node, the method comprising receiving, from a first distributed unit of the RAN node, first information indicating whether a first cell provided by the first distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

57. A program for causing a computer to perform a method for a distributed unit of a Radio Access Network (RAN) node, the method comprising: transmitting, to a central unit of the RAN node, first information indicating whether a first cell provided by the distributed unit at least partially overlaps with a No Transmission Zone (NTZ) for aerial UEs.

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