Determining a border-crossing point for uncrewed aerial systems service suppliers (USS) changeover

Abstract

Method performed by a network function (exposure function or a function for supporting uncrewed aerial service (UAS NF)) and a related apparatus are provided. The method comprises receiving by the NF from a first USS (USS1) a request for flight assistance of an uncrewed aerial vehicle (UAV) for determining a changeover to a target USS, the request indicating when the network function should notify the first USS about the UAV approaching or entering a border-crossing point. Based on a received indication of presence of the UAV in a border TA, the network function triggers a deferred Location reporting request to a location function to subscribe to deferred UAV's location events to track motion and position of the UAV inside the one or more border TA comprising a border-crossing point from USS1 and based on the received deferred location reports of the UAV, determining when the UAV approaches or enters the border-crossing point.

Description

Determining a Border-Crossing Point for Uncrewed Aerial Systems Service Suppliers (USS) Changeover Related Applications

[0001] This application claims the benefit of provisional patent application serial number 63 / 703532, filed on 10 / 4 / 2024, the disclosure of which is hereby incorporated herein by reference in its entirety. Technical Field

[0002] The present disclosure relates to a cellular communications system and, more particularly, to communication systems supporting Uncrewed Aerial Systems (UAS), UAS Service Supplier (USS) and Uncrewed Aerial Vehicle (UAV). BACKGROUND

[0003] 3GPP SA2 has completed the study phase on “Study on Phase 3 for UAS, UAV and Urban Air Mobility (UAM)” (SP-231801), and the work item is identified as FS_UAS_Ph3 has few objectives including the objective to study whether and how to enhance NEF services to support service exposure and interactions between MNOs and UTM functions for i.e. pre-mission flight planning, in-mission flight monitoring, command and control (C2) communication reliability, interfacing with UTM (e.g. supporting the scenario of multiple USS serving the geographical areas corresponding to UAV flight path) and includes the objective on how to enhance NEF services to support service exposure and interactions between mobile network operators (MNOs) and Uncrewed Aerial System Traffic Management (UTM) functions, and one of the enhancements aims at introducing support for the scenarios when UAV’s flight route goes across geographical areas administrated by different UAS service suppliers (USS-s).

[0004] One of the key issues are about the support for multiple UAS Service Suppliers (USS). The key issue has been concluded and the normative CR (see 3GPP S2-2409541) are now agreed and describes the USS changeover procedure, see clause 5.13 of 3GPP TS 23.256 incorporated by reference herein.

[0005] In order to perform USS changeover, several service operations are reused, for instance, the AMF event exposure service (i.e., Namf_EventExposure_Subscribe / Notify as specified in 3GPP TS 23.502 incorporated herein by reference) to get notified when atarget UAV enters a tracking area(TA) or a cell that borders with a geographical area served by another USS, see Step 7, 15, 17 in clause 5.13.2, Figure 5.13.2-1 of 3GPP TS 23.256 reproduced as Figure 5. The description of the steps are reproduced herein: #---excerpt from clause 5.13.2 of TS 23.256 [4] --- 1. The UAV establishes a PDU Session for communication with a serving USS (shown as USS 1 in Figure 5.13.2- 1) as described in clause 5.2.3. 2a. The UAV requests the pre-flight planning service from the serving USS, if needed. The request message includes an identifier of the UAV (e.g. GPSI, CAA-Level UAV ID), information of the starting and next point for the flight, requirements on the flight route (e.g. on time, shortest, highest, the farthest from a no-transmit zone) and may include candidate flight path(s) if available. 2b. The serving USS determines the need for the changeover to another USS based on the information about UAV's next point in the flight path or notification from the core network (e.g. UAV location reporting events from AMF / GMLC / LMF when serving USS has subscribed to such events). 3. The serving USS determines neighbouring USSs (one or more) that can serve as a target USS and triggers communication with all suitable target USSs (USS 2 in Figure 5.12.2-1) to determine candidate border-crossing point(s) for the UAV. NOTE 3: The serving USS determines suitable target USSs as well as a candidate border-crossing points between the serving USS and potential target USSs by means outside the scope of the 3GPP; for this purpose several criteria / metrics can be used, e.g. location of the next point in the flight path, area that a specific USS serves, a number of UAVs in the area served by a specific USS, proximity to no-transmit zones, USS load, etc. The serving USS in cooperation with the UTM derives any other information (e.g. acceptable deviations from the assigned flight plan / route) that can be used by 5GC to assist with the USS changeover and / or to provide flight planning assistance information. NOTE 4: The exact information that a USS can use for this purpose is outside the scope of the 3GPP, however, it can contain, for instance, information about UAV capability, geographical coordinates of the candidate border-crossing point(s), indication to reconnect to the network once the UAV enters a TA served by another USS, information about no-transmit zone (NTZ), etc. 4. The USS invokes a Nnef_UAVFlightAssistance_Get request to the NEF / UAS NF to collect from the core network information for the changeover. Inside the request, the serving USS includes the information derived in step 3 (e.g. indication about USS changeover, list of addresses for suitable target USS, a list of candidate border- crossing point(s), acceptable deviations for flight plan / route), UAV's identifier (e.g. GPSI), and other parameters such as requirements on the flight path, candidate flight path(s), accuracy level of predictions relevant to the flight planning. Editor's note: Whether Nnef_UAVFlightAssistance_Get operation is needed or not is FFS. NOTE 5: In this procedure mentioned service operations can be reused for pre-flight planning procedure as described in clause 5.12. 5. When the NEF / UAS NF receives the Nnef_UAVFlightAssistance_Get request from the serving USS with the indication about the USS changeover, the NEF / UAS NF translates / maps, if required, the parameters included in the USS request to 3GPP identifiers. For instance, the NEF determines a cell ID / tracking area identifier (TAI) of the cell / TA where the UAV-requested starting and next point in the flight path are located; similarly, if the request includes an indication that UAV will cross the USS-border and / or a list of the candidate border-crossing point(s) in form of geographical coordinates, the NEF maps them to a list of border cell IDs / TAIs. The NEF determines the relevant NFs and specific service operations it needs to invoke to collect the required information for the serving USS for the purpose of UAV flight planning (e.g. NWDAF analytics service for Movement Behaviour analytics, GMLC service for Ranging / Sidelink Positioning location, AMF for UAV's presence in bordering TAs / cells, AMF service for UAV's deviation for the expected / assigned trajectory, UDM service for expected UE behaviour parameter provision).6. The NEF / UAS NF invokes service operations towards the identified NFs as described in Steps 8-12 of the procedure for the NEF-assisted pre-flight planning, see clause 5.12. 7. If the NEF / UAS NF receives a list of candidate border-crossing points, the NEF / UAS NF identifies the AMFs serving NG-RAN nodes in all identified border TA(s) / cell(s); for that the NEF / UAS NF uses the Nnrf_NFDiscovery service from NRF. Once the AMF(s) information is retrieved, the NEF / UAS NF invokes an Namf_EventExposure_Subscribe request to subscribe to the UE / UAV's presence in area of interest wherein the area of interest is set to cell ID(s) / TAI(s) of the border cells(s) / TA(s). 8. The NEF / UAS NF responds to the Nnef_UAVFlightAssistance_Get request with the collected information from the 5GC NFs for UAV's flight path between the starting point and all candidate USS border-crossing point(s). 9. Based on the received information, the serving USS selects the target USS from the list of pre-selected suitable USSs (step 3) and starts communication to request the target USS (USS 2 in Figure 5.12.2-1) to prepare for the USS changeover and, if required, to perform the flight planning for the UAV from the border-crossing point(s) to the next point in the flight path that is located in the geographical area served by the target USS. 10. The target USS (USS 2) performs Steps 4 - 8 to plan the UAV flight across its geographical area towards the UAV's next point in the flight path. 11. The target USS (USS 2) provides the serving USS (USS 1) information about UAV's flight path(s) from a border cell(s) / TA(s) to the next point in the flight path (e.g. primary flight path, secondary / alternative flight path etc.). 12. If the UAV requests a pre-mission flight planning in step 2a, the serving USS responds to this request with the planned flight routes and time schedule for the entire flight from the starting point to the next point in the flight path. 13. The serving USS sends a Nnef_UAVFlightAssistance_Create request to the NEF / UAS NF with the information about the planned UAV flight path(s), see clause 4.4.1.1.3.3. In this request, the serving USS may also include additional flight path information for each of the segment of the paths (served by USS 1 and USS 2), for instance, UAV's speed, flight height / altitude and / or time schedule for crossing / spending at each of the TAs / cells. 14. The NEF / UAS NF may invoke additional services with 5GC NFs: with AMF to determine the UAV deviation from the expected UAV's flight trajectory (e.g. primary / secondary flight paths); with UDM to update the Expected UE Behaviour parameters via the parameter provision; with the NWDAF for the Movement Behaviour analytics of the UE / UAV to determine whether the UAV will likely leave the USS area and continue following the flight path or not. The expected UAV's flight trajectory may possibly consist of multiple segments where each of the segments are identified by geographical areas that are served by a different USSs (e.g. the currently serving USS and the target USS for the changeover). 14a. The NEF / UAS NF may use the AMF event exposure service to get notified when the UAV does not follow (i.e. deviates from) the assigned flight plan. In this case, the NEF / UAS NF sends a Namf_EventExposure_Subscribe request to the serving AMF with the planned flight path information, which consists of a list of 3GPP locations (i.e. TAIs or cell IDs), a time schedule describing when the UE shall be present at these locations, height / altitude range and, optionally, acceptable deviations, e.g. the UAV not arriving on time. Editor's note: A CR needs to be prepared for TS 23.502 [3] to add a new AMF event exposure filter in Table 5.2.2.3.1-1 of TS 23.502 [3]. The new event filter needs to support reporting when a UAV moves between different trajectory segments of the UAV. 14b. The NEF / UAS NF invokes the parameter provisioning service from the UDM (i.e. Nudm_ParameterProvision_Update, see clause 4.15.6.3 of TS 23.502 [3]) to provision the planned flight path information, which consists of a list of 3GPP locations (i.e. TAIs or cell IDs and, optionally, height / altitude information) together with the time schedule describing when the UE shall be present at these locations, optionally, acceptable deviations, e.g. UAV is not arriving on time or UAV flies below / above the assigned flight altitude. 14c. The NEF / UAS NF invokes a Nnwdaf_AnalyticsInfo_Request / Nnwdaf_AnalyticsSubscription_Subscribe service operation towards the NWDAF in order to obtain the Movement Behaviour analytics of the UE / UAV as described in clause 6.21 of TS 23.288

[0020] .15. If the NEF / UAS NF subscribes (in step 7) to UAV's presence in the borders cell(s) / TA(s)s, the AMF notifies the NEF / UAS NF once the UAV enters a border cell / TA of the serving USS about the event (i.e. UAV enters the Area of Interest). Similarly, if the NEF / UAS NF subscribes for event reporting when the UAV deviating from the expected / assigned trajectory and / or moving across different trajectory segments, the AMF notifies the NEF / UAS NF when either of the events are detected. 16. When the NEF / UAS NF receives a report from the AMF indicating the UAV is deviating the assigned flight plan, the NEF / UAS NF may invoke an Ngmlc_Location_ProvideLocation service request to a GMLC to get a accurate position of the UAV. In such case, the GMLC performs the 5G-MT-LR procedure to retrieve the accurate UAV location via AMF / LMF (as specified in TS 23.273 [8]) and provide the UAV location to the NEF / UAS NF in an Ngmlc_Location_ProvideLocation service response. 17. If the NEF / UAS NF determines that the UAV is leaving the geographical area served by the serving USS (USS 1), the NEF / UAS NF sends a Nnef_UAVFlightAssistance_Notify (as described in clause 4.4.1.1.3.5) request to the serving USS in which it includes information about which / when border-crossing point will be used by the UAV so that the USS timely triggers the changeover. 18. The serving USS communicates with the target USS to execute the changeover for the UAV; this communication and details are outside the scope of the 3GPP specification, however, it is expected that a serving USS pass the target USS the information on which exposure services / notifications are of relevance for the UAV (e.g. subscribed events and UAS NF address), UAV's identifiers (e.g. GPSI, CAA-Level UAV ID), and other information required by the target USS (or UAV itself) to establish the connection. 19. The AMF serving a border TA / cell on the target USS's side (USS 2) notifies a serving NEF / UAS NF about the UAV's presence in the border TA / cell, and the NEF / UAS NF invokes the Nnef_UAVFlightAssistance_Notify service operation to further notify the target USS. 20. The serving USS (USS 1) informs the UAV about the changeover to the new USS (USS 2) and, if required, may instruct the UAV to execute the UUAA procedure with the new USS (USS 2) as well as to trigger the exposure services towards 5GC NFs similar to what the previous USS had before the changeover. NOTE 6: Steps 19 and 20 can continue in parallel and not intended to imply sequential processing. 21. After receiving the required information from the serving USS (the exact details are outside the scope of the 3GPP specification), the target USS responds to the Nnef_UAVFlightAssistance_Notify request from the NEF / UAS NF in such a way completing the changeover for the UAV. #---end--- SUMMARY

[0006] Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. A method performed by a network function (NF) wherein the NF is a Network exposure function or an uncrewed Aerial system network function which are deployed in any telecommunication system (5G, 6G or beyond. The method comprises the step of receiving from a first uncrewed aerial system service supplier (USS1), a request for flight assistance of an uncrewed aerial vehicle (UAV) for determining a changeover to a target USS, the request includes information about when the NF should notify the USS1 about the UAV approaching or entering a border- crossing point. For example, the USS1 indicates that the NF should notify USS1 about the UAV approaching or entering a border-crossing point based on a relative distance to each of the border-crossing points. For example, the distance can be expressed in meters from the border.

[0007] In another example, the USS1 indicates to the NF when to inform USS1 about the UAV approaching / entering the border-crossing point.

[0008] In some examples, when the NF receives an indication from a core network function such as Access and Mobility management function (AMF) of presence of the UAV in a border TA, the NF triggers a deferred Location reporting request towards a location function such as LMF or GMLC to subscribe to deferred UAV’s location events reporting that will allow the NF to track motion and position of the UAV inside the one or more border TA comprising a border-crossing point from USS1. Based on received deferred location reports of the UAV, the NF determines when the UAV approaches or enters the border-crossing point.

[0009] For example, the received indication of the UAV presence is determined based on receiving from the core network function (e.g., AMF) a presence notification such as Namf_EventExposure_Notify message, about the UAV’s presence inside any one of the border TA and determining which border-crossing point the UAV is approaching or entering within the border TA by triggering the deferred location reporting request procedure to further determine UAV location info with respect to border crossing point.

[0010] In one embodiment, the method further comprises the step of notifying USS1 using for example Nnef_UAVFlightAssistance_Notify request to indicate which border- crossing point the UAV is approaching or entering based on the information received in the request from the USS1.

[0011] In some embodiment, the method further comprises the NF receiving from USS1 an indication of changeover of the UAV from USS1 to the target USS.

[0012] For example, the method comprises the step of cancelling the deferred Location reporting from the location function in response to determining the UAV leaving the border TA or in response to notifying USS1 of UAV approaching or entering border-crossing to after receiving from USS1 the indication of changeover of the UAV to a target USS.

[0013] In some embodiments a network node adapted to perform the embodiments herein or the network node comprises one or more processors and memory comprising instructions which when executed by the one or more processors enables the network node to perform any one of the embodiments herein.Brief Description of the Drawings

[0014] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0015] Figure 1 illustrates one example of a cellular communications system 100 in which embodiments of the present disclosure may be implemented;

[0016] Figures 2 and 3 illustrate example embodiments of the cellular communication system of Figure 1;

[0017] Figure 4 illustrates a cellular communication system of Figure 2 or 3 supporting UAV;

[0018] Figure 5 illustrates a flow diagram of a procedure for UAV changeover from one USS to another serving different geographical areas based on the prior art.

[0019] Figure 6 is an illustration of a single border-crossing point per border TA;

[0020] Figure 7 is an illustration a border-crossing point / polygon across multiple border TAs;

[0021] Figures 8 is an illustration of Multiple border-crossing points / polygons within a border TA;

[0022] Figures 9A illustrates a procedure for USS changeover during a UAV flight according with some embodiments;

[0023] Figures 9B illustrates a flow chart of a method implemented in a network function (e.g., NEF / UAS NF) according with some embodiments;

[0024] Figure 9C illustrates a procedure for USS changeover during a UAV flight according with the embodiments;

[0025] Figures 10, 11 are schematic block diagrams of example embodiments of a network node.

[0026] Figures 11A are schematic block diagrams of example embodiments of a NG- RAN node.

[0027] Figure 12 is a schematic block diagram of example embodiments of a network node. Description

[0028] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanyingdrawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0029] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0030] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.

[0031] Radio Node: As used herein, a “radio node” is either a radio access node or a wireless communication device.

[0032] Radio Access Node: As used herein, a “radio access node” or “radio network node” or “radio access network node” is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and / or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a basestation (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.

[0033] Core Network Node: As used herein, a “core network node” is any type of node in a core network or any node that implements a core network function. The node can be a server or system of distributed servers. Some examples of a core network node include, e.g., an Access and Mobility Management Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Short message service function (SMSF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), a Network slice Admission Control function (NSACF), a Uncrewed Aerial System (UAS) NF or the like. The Core network functions may be virtualized / containerized on a node, server, distributed servers, or implemented as a dedicated function on a dedicated physical node (compute, memory, and network). Other future core network functions in future core networks such as 6G and beyond are also applicable for this invention.

[0034] Communication Device: As used herein, a “communication device” is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, Personal Computer (PC), or Uncrewed Aerial vehicle (UAV). The communication device may be a portable, hand-held, computer- comprised, or vehicle-mounted mobile device, enabled to communicate voice and / or data via a wireless or wireline connection.

[0035] Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (IoT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance,but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, PC, or Uncrewed Aerial vehicle (UAV). The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and / or data via a wireless connection.

[0036] Network Node: As used herein, a “network node” is any node that is either part of the RAN or the core network of a cellular communications network / system.

[0037] Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.

[0038] Note that, in the description herein, reference may be made to the term “cell”; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0039] Figure 1 illustrates one example of a cellular communications system 100 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 100 is a 5G system (5GS) including a Next Generation RAN (NG-RAN) and a 5G Core (5GC); however, the present disclosure is not limited thereto. In this example, the RAN includes base stations 102-1 and 102-2, which in the 5GS include NR base stations (gNBs) and optionally next generation eNBs (ng-eNBs) (e.g., LTE RAN nodes connected to the 5GC), controlling corresponding (macro) cells 104-1 and 104-2. The base stations 102-1 and 102-2 are generally referred to herein collectively as base stations 102 and individually as base station 102. Likewise, the (macro) cells 104-1 and 104-2 are generally referred to herein collectively as (macro) cells 104 and individually as (macro) cell 104. The RAN may also include a number of low power nodes 106-1 through 106-4 controlling corresponding small cells 108-1 through 108-4. The low power nodes 106-1 through 106-4 can be small base stations (such as pico or femto base stations) or RRHs, or the like. Notably, while not illustrated, one or more of the small cells 108-1 through 108-4 may alternatively be provided by the base stations 102. The low power nodes 106-1 through 106-4 are generally referred to herein collectively as low power nodes 106 and individually as low power node 106. Likewise, the small cells 108-1 through 108-4 are generally referred to herein collectively as small cells 108 and individually as small cell 108.

[0040] In particular when the NG-RAN consists of gNBs connected to the 5GC through the NG interface, a gNB may further consist of a gNB-control unit (CU) and one or more gNB-Distribution Unit(s) (DU(s)).

[0041] The cellular communications system 100 also includes a core network 110, which in the 5G System (5GS) is referred to as the 5GC. The base stations 102 (and optionally the low power nodes 106) are connected to the core network 110.

[0042] The base stations 102 and the low power nodes 106 provide service to wireless communication devices 112-1 through 112-5 in the corresponding cells 104 and 108. The wireless communication devices 112-1 through 112-5 are generally referred to herein collectively as wireless communication devices 112 and individually as wireless communication device 112. In the following description, the wireless communication devices 112 are oftentimes UEs and as such sometimes referred to herein as UEs 112, but the present disclosure is not limited thereto.

[0043] Figure 2 illustrates a wireless communication system represented as a 5G network architecture composed of core Network Functions (NFs), where interaction between any two NFs is represented by a point-to-point reference point / interface. Figure 2 can be viewed as one particular implementation of the system 100 of Figure 1. The embodiments in the reminder of these document are described within the context of 5G network architecture using the 5G terminology, but the embodiments are also applicable to other systems / networks using network slicing, admission control of network slicing and on-demand network slicing can. Example of those systems / networks may be 6G systems / networks and beyond.

[0044] Seen from the access side the 5G network architecture shown in Figure 2 comprises a plurality of UEs 112 connected to either a RAN 102 or an Access Network (AN) as well as an AMF 200. Typically, the R(AN) 102 comprises base stations, e.g. such as eNBs or gNBs or similar. Seen from the core network side, the 5G Core network (5GC) NFs shown in Figure 2 includes but not limited to a NSSF 202, an AUSF 204, a UDM 206, the AMF 200, a SMSF 220, a SMF 208, a PCF 210, and an Application Function (AF) 212.

[0045] Reference point representations of the 5G network architecture are used to develop detailed call flows in the normative standardization. The N1 reference point is defined to carry signaling between the UE 112 and AMF 200. The reference points for connecting between the AN 102 and AMF 200 and between the AN 102 and UPF 214 are defined as N2 and N3, respectively. There is a reference point, N11, between the AMF200 and SMF 208, which implies that the SMF 208 is at least partly controlled by the AMF 200. N4 is used by the SMF 208 and UPF 214 so that the UPF 214 can be set using the control signal generated by the SMF 208, and the UPF 214 can report its state to the SMF 208. The SMSF 220 communicates with the AMF 200 over the N20 reference point, and with UDM 206 over the N21 reference point, and AMF 200 communicates with UDM 206 over the N8 reference point as illustrated in Figure 2. N9 is the reference point for the connection between different UPFs 214, and N14 is the reference point connecting between different AMFs 200, respectively. N15 and N7 are defined since the PCF 210 applies policy to the AMF 200 and SMF 208, respectively. N12 is required for the AMF 200 to perform authentication of the UE 112. N8 and N10 are defined because the subscription data of the UE 112 is required for the AMF 200 and SMF 208. N80 is the reference point between AMF 200 and NSACF 207 and N81 reference point is between SMF 208 and NSACF 207.

[0046] The 5GC network aims at separating UP and CP. The UP carries user traffic while the CP carries signaling in the network. In Figure 2, the UPF 214 is in the UP and all other NFs, i.e., the AMF 200, SMF 208, PCF 210, AF 212, NSSF 202, AUSF 204, and UDM 206, are in the CP. Separating the UP and CP guarantees each plane resource to be scaled independently. It also allows UPFs to be deployed separately from CP functions in a distributed fashion. In this architecture, UPFs may be deployed very close to UEs to shorten the Round Trip Time (RTT) between UEs and data network for some applications requiring low latency.

[0047] The 5G core network architecture is composed of modularized functions. For example, the AMF 200, SMF 208 and for example SMSF 220 are independent functions in the CP. Separated AMF 200 and SMF 208 allow independent evolution and scaling. Other CP functions like the PCF 210 and AUSF 204 can be separated as shown in Figure 2. Modularized function design enables the 5GC network to support various services flexibly.

[0048] Each NF interacts with another NF directly. It is possible to use intermediate functions to route messages from one NF to another NF. In the CP, a set of interactions between two NFs is defined as service so that its reuse is possible. This service enables support for modularity. The UP supports interactions such as forwarding operations between different UPFs.

[0049] Figure 3 illustrates a 5G network architecture using service-based interfaces between the NFs in the CP, instead of the point-to-point reference points / interfaces usedin the 5G network architecture of Figure 2. However, the NFs of the 5GC described above with reference to Figure 2 correspond to the NFs shown in Figure 3. The service(s) etc. that a NF provides to other authorized NFs can be exposed to the authorized NFs through the service-based interface. In Figure 3 the service based interfaces are indicated by the letter “N” followed by the name of the NF, e.g. Namf for the service based interface of the AMF 200 and Nsmf for the service based interface of the SMF 208, Nsmsf for service based interface exposing services of SMSF 220, etc. Any NFs depicted in Figure 2 can interact with the NEF 216 and / or NRF 218 of Figure 3 as necessary, though not explicitly indicated in Figure 2.

[0050] Some properties of the NFs shown in Figures 2 and 3 may be described in the following manner. The AMF 200 provides UE-based authentication, authorization, mobility management, etc. A UE 112 even using multiple access technologies is basically connected to a single AMF 200 because the AMF 200 is independent of the access technologies. The SMF 208 is responsible for session management and allocates Internet Protocol (IP) addresses to UEs. It also selects and controls the UPF 214 for data transfer. If a UE 112 has multiple sessions, different SMFs 208 may be allocated to each session to manage them individually and possibly provide different functionalities per session. The AUSF 204 supports authentication function for UEs or similar and thus stores data for authentication of UEs or similar while the UDM 206 stores subscription data of the UE 112. The Network Exposure Function (NEF) supports Exposure of capabilities and events, secure provision of information from external application to 3GPP network, translation of internal-external information, support of UAS NF functionality, etc. A 3GPP UAS NF support aerial functionality related to UAV identification, authentication / authorization and tracking, and to support Remote Identification. The Data Network (DN), not part of the 5GC network, provides Internet access or operator services and similar. Figure 4 illustrates an architecture of systems such as 5GS and EPS supporting UAV. The UAS Network Function in Figure 4 may be supported by the NEF or SCEF+NEF and used for external exposure of services to the USS. The UAS NF makes use of existing NEF / SCEF exposure services for UAV authentication / authorization, for UAV flight authorization, for UAV-UAVC pairing authorization, and related re-authentication / re-authorization and revocation; for location reporting, presence monitoring, obtaining list of Aerial UEs in a geographic area and control of QoS / traffic filtering. The 5GC illustrated in Figure 4 corresponds to the 5GC NFs described in Figure 3.

[0051] An NF may be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure.

[0052] In accordance with some embodiments, in order to detect whether a UAV is about to leave an area served by the USS, the NEF / UAS NF relies solely on the UAV presence in the border TA / cell such as for example receiving presence information from AMF when UAV / UE leaves the border TA / cell. Moreover, the NEF / UAS NF somehow needs to determine which border-crossing point will be used for this purpose (i.e., to move from the geographical area served by one USS to an area served by another USS). It could be sufficient under the assumption that a border TA is relatively small and there is only one border-crossing point per TA, see Fig. 6 illustrating a single border-crossing point per border TA.

[0053] However, there could be scenarios where a border-crossing point spans across multiple TA / cells (see Fig. 7), especially considering that a border-crossing point can be defined using a polygon data type (as specified in clause 6.1.6.2.9 of 3GPP TS 29.572 v. 19.0.0) and shown in table 1 below. Table 1: Definition of type Polygon Attribute name Data type P Cardinality Description shape SupportedGADShapes M 1 It shall take the value "POLYGON". pointList array(GeographicalCoordinates) M 3..15 Array with up to15 items, where each item is a "point".

[0054] Besides there might be scenarios when there are several border-crossing points per TA (for instance, when a single TA occupies a relatively large geographical area, see Fig. 8).

[0055] In scenarios / cases depicted in Fig. 7 and Fig. 8, the existing mechanisms are not sufficient to ensure that the NEF / UAS NF notifies the serving USS about the UAV leaving its service are so that the serving USS could trigger the changeover with the target USS in the timely fashion (as specified in Step 17, clause 5.13.2 of TS 23.256, Fig.5). Specifically, there is a gap of the following aspects: - no finar granularity is supported as the Subscribe / Notify is ”only” about UAV’s presence in the Area of Interest;- unclear how the NEF / UASNF determines when exactly the UAV leaves the geographical area of the serving USS (assuming that a border-crossing point can be relatively large as shown in Fig.7) and which border-crossing point will actually be used for this purpose (as there can be more than one border-crossing point per TA as shown in Fig. 8). The AMF event exposure service, which the NEF / UAS NF may additionally invoke to get notified when the UAV does not follow (i.e. deviates from) the assigned flight plan / trajectory (see Step 16 in clause 5.13.2 of TS 23.256, Fig. 5), has a TA-level granularity and therefore does not bring any additional UAV’s tracking possibility in cases when the UAV has already entered the border TA. -triggering a USS changeover with the target USS in timely fashion requires that the serving USS gets notified when the UAV enters / approaches a border-crossing point, but for that UE’s presences in the area of interest is not sufficient, instead / additionally the location services (LCS) can be used.

[0056] As stated in the introduction, there currently exist certain challenges as the existing solutions are not sufficient to ensure that the NEF / UAS NF notifies the serving USS about the UAV leaving its service are so that the serving USS could trigger the changeover with the target USS in the timely fashion.

[0057] The embodiments of the present disclosure comprise aspects related to: - Tracking the UAV / UE from the moment the NEF / UAS NF receives notification about the UAV / UE presence in the border TA until the UAV / UE enters a specific border-crossing point / polygon; - NEF / UAS NF determining towards which border-crossing point the UAV is heading (in cases there are multiple border-crossing points in a tracking area) - NEF / UAS NF determining when to inform the serving USS about the UAV / UE’s is about to enter a border-crossing point (i.e., is about to leave the geographical area served by the USS); this determination may be based on the UAV’s velocity and direction as well as the indication / instruction from the USS when the notification about UAV approaching / entering a border-crossing point need to be sent.

[0058] The embodiments herein are described in the context of 5G system, however it will be apparent to a person skilled in the art that the solution described herein can apply to any telecommunication system including 4G, 6G and beyond.

[0059] Some advantages of the solution described herein ensure support for scenarios when there are more than one border-crossing point in a tracking area and enables the timely notifications about UAV / UE approaching / entering a border-crossing point towards the serving USS for triggering the USS changeover with the target USS.

[0060] Additionally, the proposed solution provides energy and resource efficient method for determining a border-crossing point for USS changeover, since the location request shall be initiated only when the UAV is present in a border TA / cell, i.e. when the UAV approaches the USS border itself; before that the coarse granularity (on TA level) is sufficient.

[0061] Certain aspects of the present disclosure will be described in details.

[0062] Figure 9A illustrates a procedure for USS changeover during a UAV flight based on the procedure in TS 23.256 of Figure 5 modified according to embodiments of the present disclosure. The procedure is based on using 5G core network, but as indicated any suitable core network can be used such as 4G core network (EPS), 6G and beyond. This procedure can be used in conjunction with the NEF-assisted pre-flight planning as specified in clause 5.12 of TS 23.256 V. 19.0.0. USS changeover is independent of AMF(s) or NEF(s) changes, i.e. both a serving USS and a target USS can be served by the same 5GC NFs (e.g. AMF, NEF / UAS NF) during the entire UAV flight from the starting point to the next point in the flight path via the USS- determined flight path(s). Step 1. The UAV establishes a PDU Session with the 5G core network, 5GC, (based on the procedure in 3GPP TS 23.502) for communication with a serving USS (shown as USS 1 in Figure 9A) as described in clause 5.2.3 of 3GPP TS 23.256. Step 2a. The UAV requests the pre-flight planning service from the serving USS, if needed. The request message includes an identifier of the UAV (e.g. GPSI, CAA-Level UAV ID), information of the starting and next point for the flight, requirements on the flight route (e.g. on time, shortest, highest, the farthest from a no-transmit zone) and may include candidate flight path(s) if available. Step 2b. The serving USS determines the need for the changeover to another USS based on the information about UAV's next point in the flight path or notification from the core network (e.g. UAV location reporting events from AMF / GMLC / LMF when serving USS has subscribed to such events).Step 3. The serving USS determines neighbouring USSs (one or more) that can serve as a target USS and triggers communication with all suitable target USSs (USS 2 in Figure 9A) to determine candidate border-crossing point(s) for the UAV. NOTE 3: The serving USS determines suitable target USSs as well as a candidate border- crossing points between the serving USS and potential target USSs by means outside the scope of the 3GPP; for this purpose several criteria / metrics can be used, e.g. location of the next point in the flight path, area that a specific USS serves, a number of UAVs in the area served by a specific USS, proximity to no-transmit zones, USS load, etc. The serving USS in cooperation with the Uncrewed Aerial System Traffic Management (UTM) derives any other information (e.g. acceptable deviations from the assigned flight plan / route) that can be used by 5GC to assist with the USS changeover and / or to provide flight planning assistance information. NOTE 4: The exact information that a USS can use for this purpose is outside the scope of the 3GPP, however, it can contain, for instance, information about UAV capability, geographical coordinates of the candidate border-crossing point(s), indication to reconnect to the network once the UAV enters a TA served by another USS, information about no- transmit zone (NTZ), etc. Step 4. The USS invokes a Nnef_UAVFlightAssistance_Get request to the NEF / UAS NF to collect from the 5G core network information for the changeover. Inside the request, the serving USS includes the information derived in step 3 (e.g. indication about USS changeover, list of addresses for suitable target USS, a list of candidate border-crossing point(s), acceptable deviations for flight plan / route), UAV's identifier (e.g. GPSI), and other parameters such as requirements on the flight path, candidate flight path(s), accuracy level of predictions relevant to the flight planning. In this procedure mentioned service operations can be reused for pre-flight planning procedure as described in clause 5.12 of 3GPP TS 23.256. If the USS includes a list of candidate border-crossing points (e.g. expressed using sets of geographical coordinates that form an enclosed geometrical shape, i.e., polygon), the USS may also include information about when the NEF / UAS NF needs to notify the USS about the UAV / UEs approaches / enters a specific border-crossing point; this information may be specified, for instance, using a relative distance (in meters) to each of the listed border- crossing points.It is to be clarified that NEF will be aware of the geographical areas of the border-crossing points / polygons so that once the NEF receives accurate locations of the UAV, it would be able to determine how close / far the UAV is now located from the specific border-crossing point / polygon. If the UAV is closer than the provided relative distance values, which acts as a threshold for reporting, the NEF / UAS NF notifies the serving USS. Step 5. When the NEF / UAS NF receives the Nnef_UAVFlightAssistance_Get request from the serving USS with the indication about the USS changeover, the NEF / UAS NF translates / maps, if required, the parameters included in the USS request to 3GPP identifiers. For instance, the NEF determines a cell ID / tracking area identifier (TAI) of the cell / TA where the UAV-requested starting and next point in the flight path are located; similarly, if the request includes an indication that UAV will cross the USS-border and / or a list of the candidate border-crossing point(s) in form of geographical coordinates, the NEF maps them to a list of border cell IDs / TAIs. The NEF determines the relevant NFs and specific service operations it needs to invoke to collect the required information for the serving USS for the purpose of UAV flight planning (e.g. NWDAF analytics service for Movement Behaviour analytics, GMLC service for Ranging / Sidelink Positioning location, AMF for UAV's presence in bordering TAs / cells, AMF service for UAV's deviation for the expected / assigned trajectory, UDM service for expected UE behaviour parameter provision). Step 6. The NEF / UAS NF invokes service operations towards the identified NFs as described in Steps 8-12 of the procedure for the NEF-assisted pre-flight planning, see clause 5.12 of 3GPP TS 23.256. Step 7. If the NEF / UAS NF receives a list of candidate border-crossing points, the NEF / UAS NF identifies the AMFs serving NG-RAN nodes in all identified border TA(s) / cell(s); for that the NEF / UAS NF uses the Nnrf_NFDiscovery service from NRF. Once the AMF(s) information is retrieved, the NEF / UAS NF invokes an Namf_EventExposure_Subscribe request to subscribe to the UE / UAV's presence in area of interest wherein the area of interest is set to cell ID(s) / TAI(s) of the border cells(s) / TA(s). Step 8. The NEF / UAS NF responds to the Nnef_UAVFlightAssistance_Get request with the collected information from the 5GC NFs for UAV's flight path between the starting point and all candidate USS border-crossing point(s). Step 9. Based on the received information, the serving USS selects the target USS from the list of pre-selected suitable USSs (step 3) and starts communication to request thetarget USS (USS 2 in Figure 9A) to prepare for the USS changeover and, if required, to perform the flight planning for the UAV from the border-crossing point(s) to the next point in the flight path that is located in the geographical area served by the target USS. Step 10. The target USS (USS 2) performs Steps 4 - 8 to plan the UAV flight across its geographical area towards the UAV's next point in the flight path. Step 11. The target USS (USS 2) provides the serving USS (USS 1) information about UAV's flight path(s) from a border cell(s) / TA(s) to the next point in the flight path (e.g. primary flight path, secondary / alternative flight path etc.). Step 12. If the UAV requests a pre-mission flight planning in step 2a, the serving USS responds to this request with the planned flight routes and time schedule for the entire flight from the starting point to the next point in the flight path. Step 13. The serving USS sends a Nnef_UAVFlightAssistance_Create request to the NEF / UAS NF with the information about the planned UAV flight path(s), see clause 4.4.1.1.3.3 of 3GPP TS 23.256. In this request, the serving USS may also include additional flight path information for each of the segment of the paths (served by USS 1 and USS 2), for instance, UAV's speed, flight height / altitude and / or time schedule for crossing / spending at each of the TAs / cells. Step 14. The NEF / UAS NF may invoke additional services with 5GC NFs: with AMF to determine the UAV deviation from the expected UAV's flight trajectory (e.g. primary / secondary flight paths); with UDM to update the Expected UE Behaviour parameters via the parameter provision; with the NWDAF for the Movement Behaviour analytics of the UE / UAV to determine whether the UAV will likely leave the USS area and continue following the flight path or not. The expected UAV's flight trajectory may possibly consist of multiple segments where each of the segments are identified by geographical areas that are served by a different USSs (e.g. the currently serving USS and the target USS for the changeover). Step 14a. The NEF / UAS NF may use the AMF event exposure service to get notified when the UAV does not follow (i.e. deviates from) the assigned flight plan. In this case, the NEF / UAS NF sends a Namf_EventExposure_Subscribe request to the serving AMF with the planned flight path information, which consists of a list of 3GPP locations (i.e. TAIs or cell IDs), a time schedule describing when the UE shall be present at these locations, height / altitude range and, optionally, acceptable deviations, e.g. the UAV not arriving on time.Note that a new AMF event exposure filter in Table 5.2.2.3.1-1 of 3GPP TS 23.502 is required. The new event filter needs to support reporting when a UAV moves between different trajectory segments of the UAV. Step 14b. The NEF / UAS NF invokes the parameter provisioning service from the UDM (i.e. Nudm_ParameterProvision_Update, see clause 4.15.6.3 of TS 23.502 incorporated by reference) to provision the planned flight path information, which consists of a list of 3GPP locations (i.e. TAIs or cell IDs and, optionally, height / altitude information) together with the time schedule describing when the UE shall be present at these locations, optionally, acceptable deviations, e.g. UAV is not arriving on time or UAV flies below / above the assigned flight altitude. Step 14c. The NEF / UAS NF invokes a Nnwdaf_AnalyticsInfo_Request / Nnwdaf_AnalyticsSubscription_Subscribe service operation towards the NWDAF in order to obtain the Movement Behaviour analytics of the UE / UAV as described in clause 6.21 of 3GPP TS 23.288. Step 15. If the NEF / UAS NF subscribes (in step 7) to UAV's presence in the borders cell(s) / TA(s)s, the AMF notifies the NEF / UAS NF once the UAV enters a border cell / TA of the serving USS about the event (i.e. UAV enters the Area of Interest). Similarly, if the NEF / UAS NF subscribes for event reporting when the UAV deviating from the expected / assigned trajectory and / or moving across different trajectory segments, the AMF notifies the NEF / UAS NF when either of the events are detected. Step 16. When the NEF / UAS NF receives a report from the AMF indicating the UAV is deviating the assigned flight plan, the NEF / UAS NF may invoke an Ngmlc_Location_ProvideLocation service request to a GMLC to get a accurate position of the UAV. In such case, the GMLC performs the 5G-MT-LR procedure to retrieve the accurate UAV location via AMF / LMF (as specified in 3GPP TS 23.273) and provide the UAV location to the NEF / UAS NF in an Ngmlc_Location_ProvideLocation service response. Step16a. Once / if the AMF notifies the NEF / UAS NF (via an Namf_EventExposure_Notify) about the UAV / UE’s presence in any of the border TAs, the NEF / UAS NF sends a Deferred 5GC-MT-LR request (Ngmlc_Location_ProvideLocation request as specified in clause 6.3.1 of 3GPP TS 23.273 incorporated by reference) to GMLC in order to subscribe to deferred UAV’s location events tracking the UAV’s motion and position inside the border TA and towards a border-crossing point.Step 17. If the NEF / UAS NF determines that the UAV is leaving the geographical area served by the serving USS (USS 1), the NEF / UAS NF sends a Nnef_UAVFlightAssistance_Notify (as described in clause 4.4.1.1.3.5 of 3GPP TS 23.256) request to the serving USS in which it includes information about which / when border- crossing point will be used by the UAV so that the USS timely triggers the changeover. Based on the received deferred location reports of the UAV / UE’s, the NEF / UAS NF determines which border-crossing point will be used by the UAV for the USS changeover, and the NEF / UAS NF accurately determines when the UAV / UE approached / enters the border-crossing point (its polygon). If the USS in Step 4 includes information about when to inform about the UAV / UE approaching / entering the border-crossing point, the NEF / UAS NF sends the Nnef_UAVFlightAssistance_Notify request to the USS according to the provided information (for instance, when the relative distance threshold has been reached). Step 18. The serving USS communicates with the target USS to execute the changeover for the UAV; this communication and details are outside the scope of the 3GPP specification, however, it is expected that a serving USS pass the target USS the information on which exposure services / notifications are of relevance for the UAV (e.g. subscribed events and UAS NF address), UAV's identifiers (e.g. GPSI, CAA-Level UAV ID), and other information required by the target USS (or UAV itself) to establish the connection. Step 19. The AMF serving a border TA / cell on the target USS's side (USS 2) notifies a serving NEF / UAS NF about the UAV's presence in the border TA / cell, and the NEF / UAS NF invokes the Nnef_UAVFlightAssistance_Notify service operation to further notify the target USS. Step 20. The serving USS (USS 1) informs the UAV about the changeover to the new USS (USS 2) and, if required, may instruct the UAV to execute the UUAA procedure with the new USS (USS 2) as well as to trigger the exposure services towards 5GC NFs similar to what the previous USS had before the changeover. Note that Steps 19 and 20 can continue in parallel and not intended to imply sequential processing. Step 21. After receiving the required information from the serving USS (the exact details are outside the scope of the 3GPP specification), the target USS responds to theNnef_UAVFlightAssistance_Notify request from the NEF / UAS NF in such a way completing the changeover for the UAV. Step 22: The NEF / UAS NF sends an Ngmlc_Location_CancelLocation request (as specified in clause 6.3.3 of TS 23.273 [8]) to the GMLC to cancel reporting of the UAV’s location events; the NEF / UAS NF sends this request after receiving a response to the Nnef_UAVFlightAssistance_Notify request (Step 21). Alternatively, the NEF / UAS NF can cancel the reporting from GMLC is it receives a presence notification from AMF that the UE has left the border TA / cell or after notifying the serving USS that the UAV / UE is approaching or entering a border-crossing point.

[0063] Figure 9B illustrates a flow chart of a method implemented in a network function in a telecommunication system, such as a network exposure function (e.g., NEF or SCEF) in 5G or 4G core networks or a UAS NF or a combined UAS NF and network exposure function, or equivalent function in a 6G system or beyond, to facilitate determining which border-crossing point will be used for the USS changeover and informs the serving USS once the UAV enters / approaches the border-crossing point as described in Figure 9A.

[0064] The method comprises the step of receiving a request from a USS (USS1) for flight assistance of one or more UAVs to collect from a Core Network information to enable determining a changeover to a target USS (USS2). The request includes information about when the network function needs to notify the USS (USS1) about the one or more UAV / UEs approaches / enters a specific border-crossing point. The information about when the NEF / UAS NF needs to notify the USS about the UAV / UEs approaches / enters a specific border-crossing point may indicate a relative distance (e.g., in meters) to each of the border-crossing points and may indicate when to inform about the UAV / UE approaching / entering the border-crossing point.

[0065] Based on receiving an indication of the UAV presence in any of the border TAs, such as receiving from the core network (e.g., AMF) a notification (e.g., via an Namf_EventExposure_Notify) about the UAV / UE’s presence in any of the border TAs the network function, the NF triggers a deferred Location request to a location function (e.g., GMLC) to subscribe to deferred UAV / UEs location events (to track the UAV’s motion and position inside the border TA and towards a border-crossing point). Based on the received deferred location reports of the UAV / UE(s), the network function determines which border-crossing point will be used by the UAV for the USS changeover, and the NF accurately determines when the UAV approached / enters the border-crossing point.

[0066] The method further comprises the step of sending (for e.g. the Nnef_UAVFlightAssistance_Notify request) to the USS a notification according to the information included in the request (for instance, when the relative distance threshold has been reached) indicating when to inform the USS about the UAV / UE approaching / entering the border-crossing point.

[0067] Figure 10 is a schematic block diagram of a network node 1100 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node 1100 may be, for example, a core network node that implements a NF (e.g., one or more of the 5G network functions, or the like, as described herein). As illustrated, the network node 1100 includes a one or more processors 1104 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and / or the like), memory 1106, and a network interface 1108. The one or more processors 1104 are also referred to herein as processing circuitry. The one or more processors 1104 operate to provide one or more functions of the network node 1100 as described herein (e.g., one or more functions of the e.g., one or more of the 5G network functions, or the like, as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 1106 and executed by the one or more processors 1104.

[0068] Figure 11 is a schematic block diagram that illustrates a virtualized embodiment of the network node 1100 according to some embodiments of the present disclosure. Again, optional features are represented by dashed boxes. As used herein, a “virtualized” network node is an implementation of the network node 1100 in which at least a portion of the functionality of the network node 1100 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node 1100 includes one or more processing nodes 1200 coupled to or included as part of a network(s) 1202. Each processing node 1200 includes one or more processors 1204 (e.g., CPUs, ASICs, FPGAs, and / or the like), memory 1206, and a network interface 1208. In this example, functions 1210 of the network node 1100 described herein (e.g., one or more of the 5G network functions, or the like, as described herein) are implemented at the one or more processing nodes 1200 or distributed across the two or more processing nodes 1200 in any desired manner. In some particular embodiments, some or all of the functions 1210 of the network node 1100described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 1200.

[0069] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node 1100 or a node (e.g., a processing node 1200) implementing one or more of the functions 1210 of the network node 1100 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0070] Figure 11A is a schematic block diagram that illustrates a virtualized embodiment of the network node 1100 being a radio access node 1100 according to some embodiments of the present disclosure. This discussion is equally applicable to other types of network nodes. Further, other types of network nodes may have similar virtualized architectures.

[0071] As used herein, a “virtualized” radio access node is an implementation of the radio access node 1100 in which at least a portion of the functionality of the radio access node 1100 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the radio access node 1100 includes the control system 1102 that includes the one or more processors 1104 (e.g., CPUs, ASICs, FPGAs, and / or the like), the memory 1106, and the network interface 1108 and the one or more radio units 1110 that each includes the one or more transmitters 1112 and the one or more receivers 1114 coupled to the one or more antennas 1116, as described above. The control system 1102 is connected to the radio unit(s) 1110 via, for example, an optical cable or the like. The control system 1102 is connected to one or more processing nodes 1200 coupled to or included as part of a network(s) 1202 via the network interface 1108. Each processing node 1200 includes one or more processors 1204 (e.g., CPUs, ASICs, FPGAs, and / or the like), memory 1206, and a network interface 1208.

[0072] In this example, functions 1210 of the radio access node 1100 described herein are implemented at the one or more processing nodes 1200 or distributed across the control system 1102 and the one or more processing nodes 1200 in any desired manner.In some particular embodiments, some or all of the functions 1210 of the radio access node 1100 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) 1200. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) 1200 and the control system 1102 is used in order to carry out at least some of the desired functions 1210. Notably, in some embodiments, the control system 1102 may not be included, in which case the radio unit(s) 1110 communicate directly with the processing node(s) 1200 via an appropriate network interface(s).

[0073] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of radio access node 1100 or a node (e.g., a processing node 1200) implementing one or more of the functions 1210 of the radio access node 1100 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0074] Figure 12 is a schematic block diagram of the network node 1100 according to some other embodiments of the present disclosure. The network node 1100 includes one or more modules 1300, each of which is implemented in software. The module(s) 1300 provide the functionality of the network node 1100 described herein. This discussion is equally applicable to the processing node 1200 of Figure 11 / 11A where the modules 1300 may be implemented at one of the processing nodes 1200 or distributed across multiple processing nodes 1200.

[0075] In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0076] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may includeone or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and / or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.

[0077] While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0078] While processes in the figures (flow charts, procedures) may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0079] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

[0080] Some example embodiments of the present disclosure are as follows:

[0081] A method performed by a network function (e.g., NEF / UAS) NF, the method comprising: - receiving a request from a USS (USS1) for flight assistance of one or more UAV / UEs to collect from a Core Network information for determining a changeover to a target USS, the request includes information about when the NEF / UAS NF needs to notify the USS about the one or more UAV / UEs approaches / enters a specific border-crossing point; - based on an indication of the one or more UAV / UEs presence in any of the border TAs triggering a deferred Location request to a location function tosubscribe to deferred UAV’s location events (to track the UAV’s motion and position inside the border TA and towards a border-crossing point); and - based on received deferred location reports of the one or more UAV / UEs, the NF determines which border-crossing point will be used by the UAV for the USS changeover, and the NF accurately determines when the UAV approached / enters the border-crossing point.

[0082] The method of embodiment 1 wherein the information about when the NF needs to notify the USS about the UAV / UEs approaches / enters a specific border-crossing point indicates a relative distance (e.g., in meters) to each of the border-crossing points.

[0083] The method of any one of embodiment 1 and 2, wherein the information about when the NF needs to notify the USS about the UAV / UEs approaches / enters a specific border-crossing point further indicates when to inform about the UAV / UE approaching / entering the border-crossing point..

[0084] The method of any one of embodiments 1 to 3 wherein the indication of the UAV presence is determined based on receiving from the core network a notification (e.g., via an Namf_EventExposure_Notify) about the UAV’s presence in any of the border TAs

[0085] The method of embodiment 4 wherein the core network comprises an Access and mobility management function (AMF).

[0086] The method of embodiment 1 or 3 wherein the method further comprises sending (for e.g. the Nnef_UAVFlightAssistance_Notify request) to the USS a notification according to the information included in the request (for instance, when the relative distance threshold has been reached).

[0087] A network node configured to perform the method of any one of embodiments 1-6.The following is a yet another embodiment describing how some embodiments described herein can be implemented in at least 3GPP TS 23.256. The embodiment is described as a proposed modification to the text published in TS 23.256 V. 19.0.0 (changes are underlined or strikethrough):Proposed change affects: UICC apps ME Radio Access Network Core NetworkTitle: Addressing the ENs on geographical description Source to WG: Ericsson Source to TSG: SA2 Work item code: UAS_Ph3 Date: 2024-10-04 Category: F Release: Rel-19 Use one of the following categories: Use one of the following releases: F (correction) Rel-8 (Release 8) A (mirror corresponding to a change in an earlier Rel-9 (Release 9) Rel-10 (Release 10) Rel-11 (Release 11) release) … B (addition of feature), Rel-17 (Release 17) C (functional modification of feature) Rel-18 (Release 18) D (editorial modification) Rel-19 (Release 19) Detailed explanations of the above categories can Rel-20 (Release 20) be found in 3GPP TR 21.900. Reason for change: There are two editorial notes (ENs) in TS 23.256 about representation of geographical locations (i.e., flight path and a border-crossing point). -In clause 5.12 on “Pre-flight planning and in-flight monitoring”, there is the following EN: “what parameter e.g. polygon, is provided by the USS / UTM, to identify the UAV flight path, and how the network maps the parameter to the 3GPP defined area are FFS” that needs to be addressed. -In clause 4.4.1.1.3.3 (description of the Nnef_UAVFlightAssistance_Create service operation), there is an EN “Representation of the destination point and border crossing point format is FFS” that needs to be addressed. Summary of change: In regards of the first note (i.e., polygon for the representation of flight paths), polygon, as per definition in clause 6.1.6.2.9 of 3GPP TS 29.572, contain 2D information without height / altitude component. Therefore, it is not suitable for this purpose, instead it can be used to represent a border- crossing point. Considering the above, cuboids (or a set on cuboids) are more suitable (than, for instance, changing the definition of the polygon data type to include the height component) for representing a flight path. Hence, to address the EN on flight path representation, -adding a note to clarifty that: It is expected that the USS / UTM provides flight path information using a set of cuboids and, if available, corresponding timestamps / time schedule. Each of the cuboids is identified, e.g., by a set of the lowest / highest latitude, lowest / highest longitude and lowest / highestheight above the sea level in which the UAV is supposed to fly from its starting point to its next point in the assigned flight path. In order to address the EN about border-crossing point representation: - adding a NOTE stating that: (i) destination point (or a next point in the flight path) can be represented using the exisiting data type, specifically, PointAltitudeUncertainty data type as specified in clause 6.1.6.2.11 of 3GPP TS 29.572; (ii) border-crossing point can be represented using using the Polygon data type (clause 6.1.6.2.9 of 3GPP TS 29.572); no height information needs to be considered / included. Additionally, -there is a need to add clarification / restriction that, when it comes to bordering tracking areas and border-crossing points, not more than one border-crossing point per TA is considered, otherwise, the 5GC will not be able to determine which border-crossing point will be used for the USS changeover when the UAV enters a bordering TA, imposng additional mechanisms to be added (or existing to be reused) to 5GC. Therefore, the proposal is to add a NOTE clarifying that, for the USS changeover purposes, there is not more than one border-crossing point per tracking area in this realease of the specification. -bullet#2 in clause 5.12 needs to be rephrased / corrected to emphasize that NEF does not derive a flight plan for a UAV, but it exploits the existing network analytics to collect the data and expose them to the USS / UTM for pre-flight planning. The USS / UTM makes the fligh planning. Consequences if not The EN remains unresolved in the TS approved: Clauses affected: 2, 5.12.1, 5.13.2, 4.4.1.1.3.3 Y N Other specs X Other core specifications TS / TR ... CR ... affected: X Test specifications TS / TR ... CR ... (show related CRs) X O&M Specifications TS / TR ... CR ... Other comments: This CR's revision history:4.4.1.1.3.3 Nnef_UAVFlightAssistance_Create service operation Service operation name: Nnef_UAVFlightAssistance_Create Description: Providing a NEF / UAS NF information about the planned flight path(s) and a time schedule for the UAV from a starting point to a destination point (even when the destination point is located in geographical area served by different USS). Editor's note: Representation of the destination point and border crossing point format is FFS. Input, Required: UAV's identifier (e.g. GPSI). Input, Optional: Flight path information, which may include e.g. a list of TA, UAV's speed, flight height / altitude and / or time schedule for crossing / spending at each of the TAs / cells). Output, Required: Flight plan configuration ID (associated with the changeover). Output, Optional: None. >>>> Next Change <<<< 5.12.1 General 5G network may support pre-flight planning and in-flight monitoring for UAVs via the NEF service exposure. The USS / UTM may request assistance information to NEF of pre-flight planning and in-flight monitoring for UAV, after the UAV establishes user plane connection with the USS / UTM. In the case of pre-flight planning, USS / UTM may request assistance information from the to NEF for the following purposescases: (1) To determine the most suitable flight path among several candidate flight paths: USS / UTM provides multiple planned flight paths to the network, and network leverages the network analytics, e.g. Movement Behaviour Analytics and / or QoS Sustainability Analytics, to determine the most suitable (in terms of the provided criteria, e.g., fastest, shortest) planned flight path among the provided candidates. NOTE X1: It is expected that the USS / UTM provides flight path information using a set of cuboids and, if available, corresponding timestamps / time schedule. Each of the cuboids is identified, e.g., by a set of the lowest / highest latitude, lowest / highest longitude and lowest / highest height above the sea level in which the UAV is supposed to fly from its starting point to its next point in the assigned flight path. (2) To derive a flight path(s) for the requested starting and destination points for a UAV’s flight: USS / UTM provides to the networklocation information about the UAV’sof the starting and ending points for the flight to the network, and network leverages the network analytics, e.g. Movement Behaviour Analytics and / or QoS Sustainability Analytics that can be exposed via NEF, to be used by the USS / UTM to determine a detailed flight path(s) for the UAV. NEF responds to the USS / UTM with the collected network analytics outputs about the detailed flight pathto assist with the pre-flight planning. NOTE X2: Destination and / or a next point in the flight path can be described using the PointAltitudeUncertainty data type as specified in clause 6.1.6.2.11 of 3GPP TS 29.572 [R2]. (3) Output QoS information along the flight path: USS / UTM provides multiple planned flight paths to the network, and network leverages QoS Sustainability Analytics to output QoS information for each of the provided flight pathsprovided. Editor's note: What parameter e.g. polygon, is provided by the USS / UTM, to identify the UAV flight path, and how the network maps the parameter to the 3GPP defined area are FFS. In the case of in-flight monitoring, in addition to QoS Sustainability Analytics request, USS / UTM can provide the UAV flight path and corresponding (arriving) time to the network, in order for the network to verify whether the UAV's exact location matches the scheduled location represented by the waypoint.>>>> Next Change <<<< 5.13.2 Procedure for USS changeover during a UAV flight Procedure for USS changeover in cases when a UAV moves over geographical areas served by different USS is shown in Figure 5.13.2-1. NOTE 1: This procedure can be used in conjunction with the NEF-assisted pre-flight planning as specified in clause 5.12. NOTE 2: USS changeover is independent of AMF(s) or NEF(s) changes, i.e. both a serving USS and a target USS can be served by the same 5GC NFs (e.g. AMF, NEF / UAS NF) during the entire UAV flight from the starting point to the next point in the flight path via the USS-determined flight path(s). [Insert Fig.9C here] Figure 5.13.2-1: Procedure for UAV changeover from one USS to another serving different geographical areas 1. The UAV establishes a PDU Session for communication with a serving USS (shown as USS 1 in Figure 5.13.2-1) as described in clause 5.2.3. 2a. The UAV requests the pre-flight planning service from the serving USS, if needed. The request message includes an identifier of the UAV (e.g. GPSI, CAA-Level UAV ID), information of the starting and next point for the flight, requirements on the flight route (e.g. on time, shortest, highest, the farthest from a no- transmit zone) and may include candidate flight path(s) if available. 2b. The serving USS determines the need for the changeover to another USS based on the information about UAV's next point in the flight path or notification from the core network (e.g. UAV location reporting events from AMF / GMLC / LMF when serving USS has subscribed to such events). 3. The serving USS determines neighbouring USSs (one or more) that can serve as a target USS and triggers communication with all suitable target USSs (USS 2 in Figure 5.13.2-1) to determine candidate border- crossing point(s) for the UAV. NOTE 3: The serving USS determines suitable target USSs as well as a candidate border-crossing points between the serving USS and potential target USSs by means outside the scope of the 3GPP; for this purpose several criteria / metrics can be used, e.g. location of the next point in the flight path, area that a specific USS serves, a number of UAVs in the area served by a specific USS, proximity to no-transmit zones, USS load, etc. Editor's note: A term “border-crossing point” might need the revision to be more self-explanatory and is FFS. NOTE X4: A border-crossing point can be described using the Polygon data type described in clause 6.1.6.2.9 of 3GPP TS 29.572 [R2]. NOTE X5: It is assumed not more than one border-crossing point per tracking area. The serving USS in cooperation with the UTM derives any other information (e.g. acceptable deviations from the assigned flight plan / route) that can be used by 5GC to assist with the USS changeover and / or to provide flight planning assistance information. NOTE 4: The exact information that a USS can use for this purpose is outside the scope of the 3GPP, however, it can contain, for instance, information about UAV capability, geographical coordinates of the candidate border-crossing point(s), indication to reconnect to the network once the UAV enters a TA served by another USS, information about no-transmit zone (NTZ), etc. 4. The USS invokes a Nnef_UAVFlightAssistance_Get request to the NEF / UAS NF to collect from the core network information for the changeover. Inside the request, the serving USS includes the information derived in step 3 (e.g. indication about USS changeover, list of addresses for suitable target USS, a list of candidate border-crossing point(s), acceptable deviations for flight plan / route), UAV's identifier (e.g. GPSI), and other parameters such as requirements on the flight path, candidate flight path(s), accuracy level of predictions relevant to the flight planning.Editor's note: Whether Nnef_UAVFlightAssistance_Get operation is needed or not is FFS. NOTE 5: In this procedure mentioned service operations can be reused for pre-flight planning procedure as described in clause 5.12. 5. When the NEF / UAS NF receives the Nnef_UAVFlightAssistance_Get request from the serving USS with the indication about the USS changeover, the NEF / UAS NF translates / maps, if required, the parameters included in the USS request to 3GPP identifiers. For instance, the NEF determines a cell ID / tracking area identifier (TAI) of the cell / TA where the UAV-requested starting and next point in the flight path are located; similarly, if the request includes an indication that UAV will cross the USS-border and / or a list of the candidate border- crossing point(s) in form of geographical coordinates, the NEF maps them to a list of border cell IDs / TAIs. The NEF determines the relevant NFs and specific service operations it needs to invoke to collect the required information for the serving USS for the purpose of UAV flight planning (e.g. NWDAF analytics service for Movement Behaviour analytics, GMLC service for Ranging / Sidelink Positioning location, AMF for UAV's presence in bordering TAs / cells, AMF service for UAV's deviation for the expected / assigned trajectory, UDM service for expected UE behaviour parameter provision). 6. The NEF / UAS NF invokes service operations towards the identified NFs as described in Steps 8-12 of the procedure for the NEF-assisted pre-flight planning, see clause 5.12. 7. If the NEF / UAS NF receives a list of candidate border-crossing points, the NEF / UAS NF identifies the AMFs serving NG-RAN nodes in all identified border TA(s) / cell(s); for that the NEF / UAS NF uses the Nnrf_NFDiscovery service from NRF. Once the AMF(s) information is retrieved, the NEF / UAS NF invokes an Namf_EventExposure_Subscribe request to subscribe to the UE / UAV's presence in area of interest wherein the area of interest is set to cell ID(s) / TAI(s) of the border cells(s) / TA(s). 8. The NEF / UAS NF responds to the Nnef_UAVFlightAssistance_Get request with the collected information from the 5GC NFs for UAV's flight path between the starting point and all candidate USS border-crossing point(s). 9. Based on the received information, the serving USS selects the target USS from the list of pre-selected suitable USSs (step 3) and starts communication to request the target USS (USS 2 in Figure 5.13.2-1) to prepare for the USS changeover and, if required, to perform the flight planning for the UAV from the border- crossing point(s) to the next point in the flight path that is located in the geographical area served by the target USS. 10. The target USS (USS 2) performs Steps 4 - 8 to plan the UAV flight across its geographical area towards the UAV's next point in the flight path. 11. The target USS (USS 2) provides the serving USS (USS 1) information about UAV's flight path(s) from a border cell(s) / TA(s) to the next point in the flight path (e.g. primary flight path, secondary / alternative flight path etc.). 12. If the UAV requests a pre-mission flight planning in step 2a, the serving USS responds to this request with the planned flight routes and time schedule for the entire flight from the starting point to the next point in the flight path. 13. The serving USS sends a Nnef_UAVFlightAssistance_Create request to the NEF / UAS NF with the information about the planned UAV flight path(s), see clause 4.4.1.1.3.3. In this request, the serving USS may also include additional flight path information for each of the segment of the paths (served by USS 1 and USS 2), for instance, UAV's speed, flight height / altitude and / or time schedule for crossing / spending at each of the TAs / cells. 14. The NEF / UAS NF may invoke additional services with 5GC NFs: with AMF to determine the UAV deviation from the expected UAV's flight trajectory (e.g. primary / secondary flight paths); with UDM to update the Expected UE Behaviour parameters via the parameter provision; with the NWDAF for the Movement Behaviour analytics of the UE / UAV to determine whether the UAV will likely leave the USS area and continue following the flight path or not. The expected UAV's flight trajectory may possibly consist of multiple segments where each of the segments are identified by geographical areas that are served by a different USSs (e.g. the currently serving USS and the target USS for the changeover).14a. The NEF / UAS NF may use the AMF event exposure service to get notified when the UAV does not follow (i.e. deviates from) the assigned flight plan. In this case, the NEF / UAS NF sends a Namf_EventExposure_Subscribe request to the serving AMF with the planned flight path information, which consists of a list of 3GPP locations (i.e. TAIs or cell IDs), a time schedule describing when the UE shall be present at these locations, height / altitude range and, optionally, acceptable deviations, e.g. the UAV not arriving on time. Editor's note: A CR needs to be prepared for TS 23.502 [3] to add a new AMF event exposure filter in Table 5.2.2.3.1-1 of TS 23.502 [3]. The new event filter needs to support reporting when a UAV moves between different trajectory segments of the UAV. 14b. The NEF / UAS NF invokes the parameter provisioning service from the UDM (i.e. Nudm_ParameterProvision_Update, see clause 4.15.6.3 of TS 23.502 [3]) to provision the planned flight path information, which consists of a list of 3GPP locations (i.e. TAIs or cell IDs and, optionally, height / altitude information) together with the time schedule describing when the UE shall be present at these locations, optionally, acceptable deviations, e.g. UAV is not arriving on time or UAV flies below / above the assigned flight altitude. 14c. The NEF / UAS NF invokes a Nnwdaf_AnalyticsInfo_Request / Nnwdaf_AnalyticsSubscription_Subscribe service operation towards the NWDAF in order to obtain the Movement Behaviour analytics of the UE / UAV as described in clause 6.21 of TS 23.288

[0020] . 15. If the NEF / UAS NF subscribes (in step 7) to UAV's presence in the borders cell(s) / TA(s)s, the AMF notifies the NEF / UAS NF once the UAV enters a border cell / TA of the serving USS about the event (i.e. UAV enters the Area of Interest). Similarly, if the NEF / UAS NF subscribes for event reporting when the UAV deviating from the expected / assigned trajectory and / or moving across different trajectory segments, the AMF notifies the NEF / UAS NF when either of the events are detected. 16. When the NEF / UAS NF receives a report from the AMF indicating the UAV is deviating the assigned flight plan, the NEF / UAS NF may invoke an Ngmlc_Location_ProvideLocation service request to a GMLC to get a accurate position of the UAV. In such case, the GMLC performs the 5G-MT-LR procedure to retrieve the accurate UAV location via AMF / LMF (as specified in TS 23.273 [8]) and provide the UAV location to the NEF / UAS NF in an Ngmlc_Location_ProvideLocation service response. 17. If the NEF / UAS NF determines that the UAV is leaving the geographical area served by the serving USS (USS 1), the NEF / UAS NF sends a Nnef_UAVFlightAssistance_Notify (as described in clause 4.4.1.1.3.5) request to the serving USS in which it includes information about which / when border-crossing point will be used by the UAV so that the USS timely triggers the changeover. 18. The serving USS communicates with the target USS to execute the changeover for the UAV; this communication and details are outside the scope of the 3GPP specification, however, it is expected that a serving USS pass the target USS the information on which exposure services / notifications are of relevance for the UAV (e.g. subscribed events and UAS NF address), UAV's identifiers (e.g. GPSI, CAA-Level UAV ID), and other information required by the target USS (or UAV itself) to establish the connection. 19. The AMF serving a border TA / cell on the target USS's side (USS 2) notifies a serving NEF / UAS NF about the UAV's presence in the border TA / cell, and the NEF / UAS NF invokes the Nnef_UAVFlightAssistance_Notify service operation to further notify the target USS. 20. The serving USS (USS 1) informs the UAV about the changeover to the new USS (USS 2) and, if required, may instruct the UAV to execute the UUAA procedure with the new USS (USS 2) as well as to trigger the exposure services towards 5GC NFs similar to what the previous USS had before the changeover. NOTE 6: Steps 19 and 20 can continue in parallel and not intended to imply sequential processing. 21. After receiving the required information from the serving USS (the exact details are outside the scope of the 3GPP specification), the target USS responds to the Nnef_UAVFlightAssistance_Notify request from the NEF / UAS NF in such a way completing the changeover for the UAV.Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein. Abbreviation Abbreviation Explanation AFApplication FunctionAMFAccess and Mobility FunctionCNCore NetworkGMLCGateway Mobility Location controlLRLocation RequestNFNetwork FunctionUAS NFUncrewed Aerial System NFNEF Network Exposure Function NG-RAN Next generation radio access network NRF Network Repository Function OAM Operation and Maintenance PCF Policy Control Function SCEF Service control exposure function TA Tracking Area UE User Equipment UDM Unified Data Management UTM Uncrewed Aerial System Traffic Management UAV Uncrewed Aerial Vehicle USS UAS Service Supplier References 1. TR 23.700-59 v.19.0.0 (https: / / www.3gpp.org / ftp / Specs / archive / 23_series / 23.700-59 / 23700-59-j00.zip )3GPP SA2#164 CR0127 tdoc: S2-240954108 / Docs / S2-2409541.zip ) 3GPP TS 23.256 v18.2.0 (https: / / www.3gpp.org / ftp / Specs / archive / 23_series / 23.256 / 23256-i20.zip ) 3GPP TS 23.502 v.19.0.0 (https: / / www.3gpp.org / ftp / Specs / archive / 23_series / 23.502 / 23502-j00.zip )

Claims

WHAT IS CLAIMED:

1. A method performed by a network function (NF), the method comprising: - receiving from a first uncrewed aerial system service supplier (USS1), a request for flight assistance of an uncrewed aerial vehicle (UAV) for determining a changeover to a target USS, the request includes information about when the NF should notify the USS1 about the UAV approaching or entering a border-crossing point; - based on a received indication of presence of the UAV in a border TA, triggering a deferred Location reporting request to a location network function to subscribe to deferred UAV’s location events reporting to track motion and position of the UAV in the one or more border TA, wherein the border TA comprises a border-crossing point; and - based on received deferred location reports of the UAV, determining when the UAV approaches or enters the border-crossing point in the one or more border TAs.

2. The method of claim 1 wherein the network function is one of a Network Exposure function or an uncrewed Aerial system network function.

3. The method of claim 1 wherein the information about when the NF should notify the USS1 about the UAV approaching or entering a border-crossing point indicates a relative distance to each of the border-crossing points.

4. The method of claim 3 wherein the distance is indicated in meters.

5. The method of claim 1, wherein the information about when the NF should notify the USS1 about the UAV approaching or entering a border-crossing point further indicates when to inform the first USS about the UAV approaches or enters the border-crossing point.

6. The method of any one of claims 1 to 5 wherein the received indication of the UAV presence is determined based on receiving from a core network function a notification about the UAV’s presence in any one of the border TA anddetermining which border-crossing point the UAV is approaching or entering within the border TA by triggering the deferred location reporting procedure with the location network function.

7. The method of claim 6 wherein the core network function comprises an Access and mobility management function (AMF).

8. The method of claims 6 and 7 wherein receiving a notification corresponds to receiving an Namf_EventExposure_Notify message from the AMF.

9. The method of any one of claims 1 to 8 wherein the method further comprises sending to USS1 a NF notification message based on the information received in the request from the USS1, the NF notification comprising notification information indicating which border-crossing point the UAV is approaching or entering.

10. The method of claim 9 wherein the NF notification message comprises a Nnef_UAVFlightAssistance_Notify request.

11. The method of any one of claims 9 to 10 wherein the method further comprises receiving from the first USS an indication of changeover of the UAV from the first USS to the target USS in response to the NF notification message.

12. The method of any one of claims 1 to 11 wherein the method further comprises cancelling the deferred Location reporting from the location function in response to determining the UAV has left the border TA.

13. The method of method 12 wherein the determining the UAV has left the border TA comprises receiving from the core network function a notification about the UAV’s presence in the border TA as the UAV leaving the border TA.

14. The method of any one of claims 1 to 13 wherein the method further comprises cancelling the deferred Location reporting from the location function in responseto sending the NF notification to the first USS or receiving from the first USS the indication of changeover of the UAV from the first USS (USS1) to the target USS.

15. A network node configured to perform the method of any one of the method claims 1-14.

16. A network node comprising one or more processors and memory comprising instructions which when executed by the one or more processors enable the network node to perform any one of the method claims 1 to 14.

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