WO2023194013A1

WO2023194013A1 - Apparatuses and methods for optimization of interference avoidance and mitigation from ground network to uav

Info

Publication number: WO2023194013A1
Application number: PCT/EP2023/055541
Authority: WO
Inventors: Rafhael MEDEIROS DE AMORIM; István Zsolt KOVÁCS; Shahzada Basharat Rasool
Original assignee: Nokia Technologies Oy
Priority date: 2022-04-04
Filing date: 2023-03-06
Publication date: 2023-10-12

Abstract

Example embodiments provide optimization of interference avoidance and mitigation from ground network to flying unmanned aerial vehicles. Network nodes, unmanned aerial vehicles, apparatuses, methods, and computer programs are disclosed.

Description

APPARATUSES AND METHODS FOR OPTIMIZATION OF INTERFERENCE AVOIDANCE AND MITIGATION FROM GROUND NETWORK TO UAV TECHNICAL FIELD [0001] The present application generally relates to information technology. In particular, some example embodiments of the present application relate to unmanned/uncrewed aerial vehicles (UAV) and avoidance of interference with ground network nodes. BACKGROUND [0002] Some user equipment (UE) mounted in or on aircrafts, such as drones and other UAVs, may operate in the air and therefore move much higher than other UEs, such as mobile phones. It would be beneficial to improve safety of the UEs and the aircraft during their operations in the air. SUMMARY [0003] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [0004] Example embodiments may enable maintenance of a list of transmitter sources identified in a region to be avoided by flying UAVs within a specific radiofrequency zone and methods for flying UAVs to avoid such transmitter sources to mitigate interference caused by the transmitter sources. This may be achieved by the features of the independent claims. Further implementation forms are provided in the dependent claims, the description, and the drawings. [0005] According to a first aspect, a network node may comprise at least one processor; and at least one memory including computer program code; the at least one memory and the computer code configured to, with the at least one processor, cause the apparatus at least to detect a trigger to monitor and determine at least one radiofrequency zone to be avoided by a flying unmanned aerial vehicle; identify at least one object in a main direction of boresight of one or more transmitters of the network node by performing radar sensing measurements to determine the at least one radiofrequency zone to be avoided; cause broadcast of a report of the at least one radiofrequency zone to be avoided comprising at least one of an estimated location of the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and send a notification report to an unmanned aircraft system traffic management server comprising information of the determined radiofrequency zone to be avoided. [0006] According to an example embodiment of the first aspect, the trigger is based on a reception of at least one of a remote identification signal broadcasted by an unmanned aerial vehicle, a report of a remote identification signal broadcasted by an unmanned aerial vehicle in an area, a request from the unmanned aircraft system traffic management server for safety measures alongside with a flight plan of one or more unmanned aerial vehicle, an indication of an unmanned aerial vehicle in the area based on a network remote identification, and/or a request from an unmanned aerial vehicle for radiofrequency zones to be avoided. [0007] According to an example embodiment of the first aspect, the trigger comprises an indication of a radiofrequency or a subset of radiofrequencies used by the unmanned aerial vehicle or relevant for monitoring, and the radar sensing measurements are performed only for the indicated radiofrequencies. [0008] According to an example embodiment of the first aspect, the radar sensing measurements are performed across each of the one or more transmitters quasi-co-located with relevant transmitters of other network nodes determined based on previously reported locations of transmitter sources of interference. [0009] According to an example embodiment of the first aspect, the at least one memory and the computer code configured to, with the at least one processor, cause the network node to send a request to one or more user equipment to broadcast the report of the at least one radiofrequency zone to be avoided. [0010] According to an example embodiment of the first aspect, the radar sensing is performed in a given time interval having a start time and an end time determined by an entity which provided the trigger. [0011] According to an example embodiment of the first aspect, the report is broadcasted via detect-and- avoidance signaling format over an PC5 interface. [0012] According to a second aspect, an unmanned aerial vehicle may comprise at least one processor; and at least one memory including computer program code; the at least one memory and the computer code configured to, with the at least one processor, cause the unmanned aerial vehicle at least to obtain information indicative of an area comprising at least one transmitter as a potential source of interference along a flight plan of the unmanned aerial vehicle; determine at least one of a position or a direction of the at least one transmitter; determine at least one radiofrequency zone to be avoided based on an average interference exceeding a threshold in a communication channel of the unmanned aerial vehicle due to the at least one transmitter; and send a notification comprising information about the at least one radiofrequency zone to be avoided to at least one of an unmanned aircraft system traffic management server or a controller of the unmanned aerial vehicle. [0013] According to an example embodiment of the second aspect, the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a reception of a report of a radiofrequency zone to be avoided comprising at least one of an location of a transmitter, a location of an entity reporting on the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and wherein the at least one memory and the computer code are further configured to, with the at least one processor, cause the unmanned aerial vehicle to broadcast the received report. [0014] According to an example embodiment of the second aspect, the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a request sent to a serving network node for a list of transmitters relevant for the flying unmanned aerial vehicle based on at least one of a radio frequencies associated to the unmanned aerial vehicle or a flight plan of the unmanned aerial vehicle. [0015] According to an example embodiment of the second aspect, the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a detected increase of an overall interference power of radiofrequency channels associated with radiofrequency channels used by the unmanned aerial vehicle. [0016] According to an example embodiment of the second aspect, at least one of the position or the direction is determined based on at least one of a gradient of the received power along a flight route of the unmanned aerial vehicle, a request of help from a network node to use the network node and network node users radar sensing capabilities to refine the position of the transmitter, a request for a network node database on relevant transmitters for a given radiofrequency in the region, a request of a cloud-based database on relevant transmitters for a given radiofrequency in the region, a request for a network node for beam characteristics of the transmitter, or a request for a core network for beam characteristics of the transmitter. [0017] According to an example embodiment of the second aspect, the broadcasted report further comprises at least one of an orientation and height an antenna of the unmanned aerial vehicle, a receiver class specific safety distances, a safety distance from the reported location of the transmitter for a given antenna orientation of an unmanned aerial vehicle, or beam characteristics of the transmitter. [0018] According to a third aspect, a method may comprise detecting a trigger to monitor and determine at least one radiofrequency zone to be avoided by a flying unmanned aerial vehicle; identify at least one object in a main direction of boresight of one or more transmitters of the network node by performing radar sensing measurements to determine the at least one radiofrequency zone to be avoided; causing broadcast of a report of the at least one radiofrequency zone to be avoided comprising at least one of an estimated location of the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and sending a notification report to an unmanned aircraft system traffic management server comprising information of the determined radiofrequency zone to be avoided. [0019] According to an example embodiment of the third aspect, the trigger is based on a reception of at least one of a remote identification signal broadcasted by an unmanned aerial vehicle, a report of a remote identification signal broadcasted by an unmanned aerial vehicle in an area, a request from the unmanned aircraft system traffic management server for safety measures alongside with a flight plan of one or more unmanned aerial vehicle, an indication of an unmanned aerial vehicle in the area based on a network remote identification, or a request from an unmanned aerial vehicle for radiofrequency zones to be avoided. [0020] According to an example embodiment of the third aspect, the trigger comprises an indication of a radiofrequency or a subset of radiofrequencies used by the unmanned aerial vehicle or relevant for monitoring, and the radar sensing measurements are performed only for the indicated frequencies. [0021] According to an example embodiment of the third aspect, the radar sensing measurements are performed across each of the one or more transmitters quasi-co-located with relevant transmitters of other network nodes determined based on previously reported locations of transmitter sources of interference. [0022] According to an example embodiment of the third aspect, the method further comprises sending a request to one or more user equipment to broadcast the report of the at least one radiofrequency zone to be avoided. [0023] According to an example embodiment of the third aspect, the radar sensing is performed in a given time interval having a start time and an end time determined by an entity which provided the trigger. [0024] According to an example embodiment of the third aspect, the report is broadcasted via detect-and- avoidance signaling format over an PC5 interface. [0025] According to a fourth aspect, a method may comprise obtaining information indicative of an area comprising at least one transmitter as a potential source of interference along a flight plan of the unmanned aerial vehicle; determining at least one of a position or a direction of the at least one transmitter; determining at least one radiofrequency zone to be avoided based on an average interference exceeding a threshold in a communication channel of the unmanned aerial vehicle due to the at least one transmitter; and sending a notification comprising information about the at least one radiofrequency zone to be avoided to at least one of an unmanned aircraft system traffic management server or a controller of the unmanned aerial vehicle. [0026] According to an example embodiment of the fourth aspect, the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a reception of a report of a radiofrequency zone to be avoided comprising at least one of an location of a transmitter, a location of an entity reporting on the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and wherein the at least one memory and the computer code are further configured to, with the at least one processor, cause the unmanned aerial vehicle to broadcast the received report. [0027] According to an example embodiment of the fourth aspect, the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a request sent to a serving network node for a list of transmitters relevant for the flying unmanned aerial vehicle based on at least one of a frequencies associated to the unmanned aerial vehicle or a flight plan of the unmanned aerial vehicle. [0028] According to an example embodiment of the fourth aspect, the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a detected increase on an overall received power over time series of radiofrequency channels associated with radiofrequency channels used by the unmanned aerial vehicle. [0029] According to an example embodiment of the fourth aspect, at least one of the position or the direction is determined based on at least one of a gradient of the received power along a flight route of the unmanned aerial vehicle, a request of help from a network node to use the network node and network node users radar sensing capabilities to refine the position of the transmitter, a request for a network node database on relevant transmitters for a given radiofrequency in the region, a request of a cloud-based database on relevant transmitters for a given radiofrequency in the region, a request for a network node for beam characteristics of the transmitter, or a request for a core network for beam characteristics of the transmitter. [0030] According to an example embodiment of the fourth aspect, the broadcasted report further comprises at least one of an orientation and height an antenna of the unmanned aerial vehicle, a receiver class specific safety distances, a safety distance from the reported location of the transmitter for a given antenna orientation of an unmanned aerial vehicle, or beam characteristics of the transmitter. [0031] According to a fifth aspect, a computer program may be configured, when executed by a processor, to cause an apparatus at least to perform the following: detect a trigger to monitor and determine at least one radiofrequency zone to be avoided by a flying unmanned aerial vehicle; identify at least one object in a main direction of boresight of one or more transmitters of the network node by performing radar sensing measurements to determine the at least one radiofrequency zone to be avoided; cause broadcast of a report of the at least one radiofrequency zone to be avoided comprising at least one of an estimated location of the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and send a notification report to an unmanned aircraft system traffic management server comprising information of the determined radiofrequency zone to be avoided. The computer program may further comprise instructions for causing the apparatus to perform any example embodiment of the method of the third aspect. The apparatus may comprise a network node. [0032] According to a sixth aspect, a computer program may be configured, when executed by a processor, to cause an apparatus at least to perform the following: obtain information indicative of at least one area comprising a transmitter as a potential source of interference along a flight plan of the unmanned aerial vehicle; determine at least one of a position or a direction of the at least one transmitter; and determine at least one radiofrequency zone to be avoided based on an average interference exceeding a threshold in a communication channel of the unmanned aerial vehicle due to the at least one transmitter; send a notification comprising information about the at least one radiofrequency zone to be avoided to at least one of an unmanned aircraft system traffic management server or a controller of the unmanned aerial vehicle. [0033] According to a seventh aspect, a network node may comprise means for detecting a trigger to monitor and determine at least one radiofrequency zone to be avoided by a flying unmanned aerial vehicle; means for identifying at least one object in a main direction of boresight of one or more transmitters of the network node by performing radar sensing measurements to determine the at least one radiofrequency zone to be avoided; means for causing broadcast of a report of the at least one radiofrequency zone to be avoided comprising at least one of an estimated location of the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and means for sending a notification report to an unmanned aircraft system traffic management server comprising information of the determined radiofrequency zone to be avoided. The network node may further comprise means for performing any example embodiment of the method of the third aspect. [0034] According to an eighth aspect, an unmanned aerial vehicle may comprise means for obtaining information indicative of an area comprising at least one transmitter as a potential source of interference along a flight plan of the unmanned aerial vehicle; means for determining at least one of a position or a direction of the at least one transmitter; means for determining at least one radiofrequency zone to be avoided based on an average interference exceeding a threshold in a communication channel of the unmanned aerial vehicle due to the at least one transmitter; and means for sending a notification comprising information about the at least one radiofrequency zone to be avoided to at least one of an unmanned aircraft system traffic management server or a controller of the unmanned aerial vehicle. [0035] Many of the attendant features will be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings. DESCRIPTION OF THE DRAWINGS [0036] The accompanying drawings, which are included to provide a further understanding of the example embodiments and constitute a part of this specification, illustrate example embodiments and together with the description help to explain the example embodiments. In the drawings: [0037] FIG. 1 illustrates an example of a communication network comprising a network node and at least one aerial user node according to an example embodiment; [0038] FIG. 2 illustrates an example of a geometry of a boresight region of an antenna according to an example embodiment; [0039] FIG. 3 illustrates a message sequence chart for detection and avoidance of one or more potential transmitter sources of interference according to an example embodiment; [0040] FIG. 4 illustrates a message sequence chart for detection and avoidance of one or more potential transmitter sources of interference according to another example embodiment; [0041] FIG. 5 illustrates an example of an apparatus configured to practice one or more example embodiments; [0042] FIG. 6 illustrates an example of a method for detection and avoidance of one or more potential transmitter sources of interference, according to an example embodiment; [0043] FIG. 7 illustrates an example of a method for detection and avoidance of one or more potential transmitter sources of interference performed, according to another example embodiment. DETAILED DESCRIPTION [0044] Reference will now be made in detail to example embodiments, examples of which are illustrated in the accompanying drawings. The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present examples may be constructed or utilized. The description sets forth the functions of the example and a possible sequence of operations for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples. [0045] Remote identification (ID) may be a mandatory feature for registered unmanned, or uncrewed, aerial systems (UAS) and unmanned, or uncrewed, aerial vehicles (UAV), such as drones. UAS and UAV are also known as unmanned aircraft systems/vehicles or remotely piloted vehicles. UAS may refer to an UAV or drone and its equipment to control the UAV/drone remotely. In general, remote ID is the ability of an UAV in flight to provide identification and location information that can be received by other parties. The remote ID may provide information comprising, for example, an identity, a location, and an altitude of the vehicle in flight and its control station or take-off location. For example, authorized individuals from public safety organizations may request an identity of an owner of the UAV. [0046] An UAV may be a standard remote ID UAV or an UAV with a remote ID broadcast module. The UAV may be configured to broadcast its remote ID information via a radio frequency using, for example, Wi-Fi or Bluetooth. In the standard remote ID UAV, the remote ID capability is built into the UAV. In the UAV with remote ID broadcast module, the remote ID capability is provided through a module attached to the UAV. The UAV may transmit the following message elements, from take-off to shutdown: a unique identifier for the UAV; the UAV's latitude, longitude, geometric altitude, and velocity; an indication of the latitude, longitude, and geometric altitude of a control station (standard remote ID UAV) or a take-off location (UAV with remote ID broadcast module); a time mark; and an emergency status (standard remote ID UAV only). [0047] 3GPP Rel-17 TS 23.256 specifies architecture enhancements for supporting uncrewed aerial systems (UAS) connectivity, identification, and tracking, according to the use cases and service requirements defined in TS 22.125. [0048] A network Remote ID is an online type of a remote ID, where a flight plan and remote ID information of UAVs in a given area may be present in a remote server and can be accessed by external parties (such as members of the public, police, authorities, other UAV controllers, etc.) and retrieved from the server. [0049] With the network-based remote IDs, a list of UAV IDs altogether with their flight plans may be available on the server at all times. The network remote ID may be optional for small UAVs but mandatory for large UAVs or operations in a Unified Airspace (U-Space) where the UAVs share highways with other equipment/transportation. U-space is a set of services and specific procedures designed to support safe, efficient and secure access to airspace for large numbers of UAVs. [0050] FIG. 1 illustrates an example of a communication network 100 comprising a network node and at least one aerial user node according to an example embodiment. [0051] The communication network 100 may comprise one or more base stations, represented by the NG-RAN 104 (new generation radio access network node). The NG-RAN 104 may be also called a gNB, RU (radio unit), DU (distributed unit) or a TRP (transmission-receiver point). Network elements, such as NG-RAN, may be generally referred to as network nodes or network devices. Although depicted as a single device, a network node may not be a stand-alone device, but for example a distributed computing system coupled to a remote radio head. The communication network 100 may further comprise one or more client nodes, which may be also referred to as a user nodes or UE 106. The communication network comprises one or more UAVs 102, which may be referred to as aerial UEs or UAV-mounted UEs. [0052] In an embodiment, the UAV 102 may be a drone mounted with wireless equipment. The UAV 102 may comprise, for example, at least one of a UE or a base station. The UE and/or base station may be mounted, for example, on or in the drone/UAV 102. The UAV 102 mounted with a base station is also called an aerial base station. The UAV 102 may be controlled, for example, remotely by a RF module, and/or the UAV 102 may comprise an on-board computing device for autonomous operation by cooperating with the network. [0053] The communication network 100 may be configured for example in accordance with the 5th Generation digital cellular communication network, as defined by the 3rd Generation Partnership Project (3GPP). In one example, the communication network 100 may operate according to 3GPP 5G-NR. It is however appreciated that example embodiments presented herein are not limited to this example network and may be applied in any present or future wireless or wired communication networks, or combinations thereof, for example other type of cellular networks, short-range wireless networks, broadcast or multicast networks, or the like. The UE 106 and UAV 102 may communicate with the NG-RAN 104 via wireless radio channel(s). Communications between UE 106, UAV 102, and NG-RAN 104 may be bidirectional. Hence, any of the devices may be configured to operate as a transmitter and/or a receiver. [0054] Certain 3GPP 5G NR (new radio) UE categories have mmWave communication capabilities. The mmWave radio transmission can be used for both communication and radar sensing purposes. UEs with mmWave capabilities may provide radar sensing functionalities, e.g., in the 60GHz or above bands. At least one of the UE 106 or UAV 102 may be configured for radar sensing. [0055] A radio enabled device such as the UE 106 (e.g., a smartphone or a tablet) may be configured to request or detect a remote ID broadcasted by the UAV 102 in visual line-of-sight (VLOS) and simultaneously perform radar sensing. The radar sensing may be active, where the transmitter (the UE 106) and receiver (UAV 102) can communicate with each other, or passive, where the transmitter only measures the radio reflections from the target ‘receiver’. With the passive radar sensing procedure, radio communication between the UAV 102 and the UE 106 may not be required. [0056] The UAV 102 may have cellular connectivity (e.g., 4G/5G). If the cellular connection is available, the UAV 102 may not have to be necessarily with mmWave bands support. For the UAV 102 with cellular connectivity, the NG-RAN 104 may provide advanced functionalities and dedicated interfaces to a regional UTM (or U-Space in Europe). [0057] UTM (unmanned/uncrewed aircraft system traffic management) is an air traffic management ecosystem under development for autonomously controlled operations of unmanned aerial systems comprising concepts of operation, data exchange requirements, and a supporting framework to enable multiple UAS operations beyond visual line-of-sight at altitudes under 400 ft above ground level in airspace. While the UTM/U-space may be in full control of the UAV 102 (such as a flight path, a mission, etc.), the radio connectivity (quality of service, QoS, provisioning) and related location services may be handled by the NG-RAN 104. For a UAV 102 without cellular connectivity, the network may not provide any direct support. [0058] Current activities on GSM, GUTMA (Global UTM Association) and ACJA (Aerial Connectivity Joint Activity) are discussing the minimum operational capabilities expected and a possible set of requirements for a detection-and-avoidance (DAA) mechanisms. The DAA functionality may support a broadcast message that conveys DAA alerts and potential “list of obstacles”. However, detection and avoidance of only physical obstacles may not be enough to ensure safety in all situations. [0059] Radiofrequency (RF) transmissions of nearby cellular towers may cause problems to flying UAVs. This is related to the fact that high-gain antennas (between 18-23 dBi) have their boresight (region of maximum gain in the azimuthal plan) pointed towards the UAV position, which may be located at just a dozen meters away. In contrast, conventional UEs may be either shielded by buildings and other scatter elements, located at farther distances and usually not in the boresight of the antenna. For example, the antennas may cause interfering with a communication module of the UAV, which may use adjacent channels (e.g., 2.4 GHz). As the UAV controller may utilize a 2.4 GHz open frequency, there is also a possibility that an outdoor WI-FI repeater is installed in the region and contributes to the increased interference level. The high interference level may cause the UAV to lose the communication link with the controller and trigger a safe response. [0060] FIG. 2 illustrates an example of a geometry of a boresight region of an antenna 200 according to an example embodiment. The antenna 200 may be mounted, for example, on a NG-RAN 104. The boresight may refer to the direction and/or region of maximum transmitted power for a given transmission from an antenna or an array of antennas. [0061] In the example of FIG. 2, an UAV 102 may be flying at a height which is roughly the height of antenna mountings located above rooftops such as at 38 m of height (h_UAV). A UE 106 may be located closer to a ground level, such as at a height of 1.5 m (h_UE). The UAV 102 and UE 106 may be both located at the antenna boresight which may be downtilted, for example, in 6 degrees. Typical downtilting values are between 0 and 6 degrees, or even higher in very dense urban areas. Assuming free- space propagation and a frequency of 2.5 GHz, and antenna gain of 20 dB at the boresight, the received power at the flying UAV 102 (at a distance d_UAV and the height h_UAV) may be 25 dB higher than for the UE 106 on the ground (at a distance d_UE and the height h_UE). In practice, the difference may be much larger, as at such distances close to ground level (e.g., d_UE, h_UE) there is a low likelihood of line-of-sight, and higher losses are expected. [0062] With NR beams, and potentially FR2 usage, the beam gain at boresight may be very high. Especially when the beams are used for compensating to higher propagation losses which may be expected at commonly observed cellular distances. But as UAVs fly closer to base stations, with much higher likelihood of line of sight, this tends to be an overcompensation. Moreover, the number of beams can be quite high (>32) from the same TRP (transmit-receiver point), and they may vary their orientation dynamically, being hard to predict where the area of higher interference will be. [0063] Based on above, the UAVs may need a “RF safety distance” that may extend larger than the physical safety distance required for avoiding collision with elements in the scenario. The RF safety distance may refer to a radiofrequency area or zone associated to at least one transmitter source which may interfere with flying UAVs when the UAV enters the area. [0064] A secondary scenario also addressed by this disclosure is TV and radio transmitters, which transmit at a much lower frequency with a total transmit power that is orders of magnitude higher than the commonly observed in 3GPP networks, for example. Usually, the TV and radio transmitters are not considered a problem for devices on the ground, as the transmitters are placed in high towers. However, as UAVs are flying, the height dimension may not create enough separation between UAVs and these transmitters. As such transmitters are at much lower frequency ranges, their near-field can extend for dozens of meters. In this case, radio effects can cause self-inductive effects in UAV elements. To avoid these harmful and dangerous effects, some of the TV and radio transmitters may need to be mapped onto no-fly zones. [0065] An example embodiment may provide creation and maintenance of radiofrequency zones with safety distances to avoid interference between a static transmitter and a flying UAV. The transmitter to be avoided may be, for example, a Wi-Fi AP (access point) or a base station, such as NG-RAN radio cell. A spherical radius may not be an optimal choice for the radiofrequency zone to be avoided, as it isolates a large area around the transmitter, and not only the RF relevant area. The safety distances may be determined in three dimensions to cover the RF relevant area more precisely. If the radiofrequency zone is not limited only to the relevant area based on potential interference, it could preclude the UAV, for example, to do property inspections in a site close to a RF antenna. [0066] According to an example embodiment, a detection procedure may be initiated by a base station to actively look for UAVs potentially entering a RF safety-area in control of the base station. [0067] The detection procedure may comprise creating the RF zone to be avoided based on a trigger. The trigger may be based on, for example, detection and decoding of the remote ID signal broadcasted by the UAV. The detection procedure may further comprise scanning of objects in the main direction of the antennas’ boresights. The scanning may be based on active radar sensing. The radar sensing may comprise using very high frequency (mmWave range) transmissions and based on received reflections of the transmissions estimating the distance to potential obstacles in the direction. [0068] The detection procedure may comprise a novel detect-and-avoid signaling format for supporting RF safety-area reporting to be broadcasted by a NG-RAN node. The broadcasting may be implemented, for example, via DAA over PC5. PC5 is an interface used for direct communication between a vehicle and other devices. In PC5, communication with a base station is not required. The detection procedure may comprise sending a notification report to UTM with a notification of the new RF zone. [0069] According to an embodiment, the UAV may be configured to search, discover, and report RF zones to be avoided, i.e., to determine the RF zone with safety distance. The safety distance may refer to a distance where an expected received power from a certain transmitter source is below a predetermined threshold. The UAV may be configured to actively discover potentially dangerous areas (RF-wise) and determine location and/or range of the potential RF sources of interference. The UAV may be configured to calculate potential impact of the RF-area in a flight plan. The UAV may be further configured to send information of the RF zone to be avoided to the UTM and an UAV controller, and transmit supporting RF zone reporting, for example, using the novel detect-and-avoid signaling format. [0070] Advantages of example embodiments may comprise providing more layer of safety to DAA procedures by taking into consideration RF propagation areas to be avoided, on top of physical collision avoidance procedures. Further, failure conditions on the UAV operation may be minimized. [0071] FIG. 3 illustrates a message sequence chart for detection and avoidance of one or more potential transmitter sources of interference according to an example embodiment. In an embodiment, the NG-RAN 104 may be the main actor configured to proactively create RF- safe zones. [0072] Although intended for macro base stations on a general sense, the procedure also suits very well to scenarios where transmitters are deployed by the NG-RAN temporarily (which will not be part of UTM database for flight plans and no-fly zones, even if full-transparency is adopted between NG-RAN and UTM agreements). This is the case, for example of HAPS (high-altitude platform system) deployments (radio stations located on an object at an altitude of 20-50 kilometers and at a specified, nominal, fixed point relative to the Earth, for example) and mobile base stations (used in mass events, for example). [0073] At 302, the UAV 102 initiates an operation, such as a flight mission. [0074] At 306, the NG-RAN 104 may be configured to observe a trigger for new monitoring and creation of RF zones with safety distances. The trigger may be generated when any of the below conditions are met. [0075] A first condition may be based on the NG-RAN 104 node detecting a reception of UAV Broadcast Remote ID, such as the remote ID signal broadcasted by the UAV 102 at 304. [0076] A second condition may be based on a report from a UE to the NG-RAN 104 of a reception of UAV broadcast remote ID in the area. In an embodiment, the report may be treated by a core network which may process the information and be in charge of the decisions for triggering the procedure. The UE may be another UAV. [0077] A third condition may be based on a request sent by UTM 300 to the NG-RAN 104 requiring safety measures alongside with an UAV flight plan of one or more UAVs. [0078] A fourth condition may be based on the NG-RAN 104 identifying UAVs in the area based on network remote ID information. The network remote ID information may be received, for example, from the UTM 300. [0079] A fifth condition may be based on a request from the UAV for “RF-protected” zones, i.e., information about RF zones to be avoided. [0080] If any of the triggers above comprise an indication for a radio frequency (or subset of radio frequencies) used by the UAV 102 or relevant for monitoring, the NG-RAN 104 may skip measurements in the non-relevant transmitters. The other frequencies relevant for monitoring may comprise, for example, frequencies co-located or adjacent to the frequencies used by the UAV 102. In addition, the relevant frequencies may represent harmonic frequencies. [0081] In an embodiment, the detecting node (NG-RAN 104) may be aware of previously reported locations for potential transmitter sources of interference. The locations may be maintained internally in the network from previous procedures. Alternatively, or in addition, the locations of previously reported locations for potential transmitter sources of interference may be acquired via signaling. In an embodiment, the NG-RAN 104 may perform radar sensing measurements in its transmitting points quasi-co-located with potentially relevant (e.g., interfering) transmitters from others NG-RAN nodes (gNB, RU, DU) or other non-3GPP technologies (for example, other WI-FI access points). [0082] At 308, the NG-RAN node 104 may be configured to perform active radar sensing to identify possible objects (UAVs) in the area. The radar sensing may be focused on the boresight region of the transmitter antennas on the NG-RAN side. The NG-RAN 104 may be configured to utilize a position or flight information comprised in the triggers described in operation 306 to narrow down the search to the relevant areas. [0083] In an embodiment, the active radar sensing may be configured to take place only in a given time period. In an embodiment, the entity issuing the trigger in operation 306 may configure a start and an end time of the time period. For example, the UAV 102 may be passing by a region close to the NG-RAN node 104. The radar sensing measurements may be configured to be performed when the UAV is close by to the NG-RAN 104 based on the given time interval. The idea is to obtain a comprehensive view of the UAVs in one area, but without straining the power consumption and usage of resources of the NG-RAN node 104 too much, as the resources may not be used for radio purposes while in use for radar sensing. [0084] At 310, in order to help the UAV 102 and other UAVs in the region, the NG-RAN 104 may be configured to start a broadcast a report comprising information about the RF zone to be avoided in the region. The NG-RAN 104 may be configured to determine the RF zone in three dimensions, for example, based on a safety distance from a location of the transmitter source and/or a direction or an angular spread of the transmitter source. The other UAVs may be associated to other NG-RAN nodes or not associated to any NG-RAN. In addition, or alternatively, at 312 the NG-RAN 104 may be configured to request other UEs to broadcast the report (316) via PC5. In general, the report may be communicated through radio signaling, such as DAA signaling. [0085] The RF zone to be avoided may be static or dynamic. In an embodiment, the NG-RAN 104 may be configured to determine a static RF zone, for example, based on knowledge of the transmitter antenna and/or beam radiation pattern and transmit power of the NG-RAN 104. The static RF zone may be defined, for example, as a volume or area within which the estimated received power is above a certain threshold value. When the received power is above the certain threshold, the UAVs may experience interference. Hence, the UAVs may avoid entering such areas. The static RF zone may assume no UAV antenna gain or directivity. [0086] In an embodiment, the NG-RAN 104 may be configured to determine a dynamic RF zone based on the static RF zone. The static RF zone may be adapted (finetuned) based on a set of repeated radar sensing measurements. Each radar sensing measurement may be, for example, offset in time and spatial domain, similar to classical radar systems. The offset in spatial domain may be achieved, for example, by means of using radio beams or beamforming, as implemented in 5G mmWave communications. Each radar sensing measurement may be used to estimate an orientation and distance to the detected UAV. The orientation and distance estimates may be used to check if the detected UAV is within the static RF zone. If the UAV is estimated to be within the static RF zone, the NG-RAN 104 may be configured to trigger, for example, the broadcast of the radiofrequency zone to be avoided. [0087] In an embodiment, if the UAV is estimated to be outside the static RF zone, the remote ID information received from the UAV 102 may be checked by the NG-RAN 104. In addition, signal strength values, such as received power over time series, of the received remote ID message may be compared by the NG-RAN 104, for example, to a certain threshold value. If the NG-RAN 104 determines that the received signal strength is above the certain threshold value, the UAV 102 may be considered to be within the RF zone to be avoided. For example, the UAV 102 might be using a directional or a beamforming antenna, and therefore radiofrequency channels of the UAV 102 may be interfered by the radio transmission from the network node. The directions and distances to the UAVs may be used to adapt/tune the static RF zone. Based on the adapted static RF zone, the NG-RAN 104 may be configured to trigger the broadcast of the new radiofrequency zone to be avoided. If the UAV 102 is considered to be outside the RF zone, no action may be taken by the NG-RAN 104. This is only one example for creation of the static and dynamic RF zones and various other combinations of the above steps can be used. For example, the NG-RAN 104 may be configured to store the received remote ID along with previously estimated dynamic RF zone. If the NG-RAN then identifies a known or previously received ID, the NG-RAN 104 may re-use the ‘customized’ RF zone for that UAV, or a group of UAVs. [0088] The report may comprise information of the estimated location of the transmitter source. In addition, or alternatively, the report may comprise the direction of transmission of the reported transmitter source. In addition, or alternatively, the report may comprise a frequency channel of the reported transmitter source. In addition, or alternatively, the report may comprise the safety distance from the reported location of the transmitter source. In addition, or alternatively, the NG-RAN 104 may be configured to request the UAV 102 to broadcast the report. In an embodiment, the report may comprise instructions for the broadcast, such as one or more start time and stop time for the broadcast. The start and the stop time may be received, for example, from an entity which provided the trigger or from UTM 300. The time information may be used to indicate the time validity of the RF zone to be avoided by the UAVs. [0089] Based on the broadcasted information about the RF zones, flying UAVs in the neighborhood of the NG-RAN 104 may be able change their flying paths to avoid interference with the transmitters associated with the RF zones. [0090] At 314, the NG RAN 104 may be configured to send a notification to the UTM 300 comprising the new RF safety area information. Hence, the UTM 300 may maintain a list of RF zones to be avoided by the flying UAVs. [0091] FIG. 4 illustrates a message sequence chart for detection and avoidance of one or more potential transmitter sources of interference according to another example embodiment. In an embodiment, the UAV 102 may be the actor seeking to protect itself from a potential harm by avoiding interference during its flying path. [0092] At 402, the UAV 102 may be configured to initiate an operation, such as a flight mission. The flight mission may be registered in the UTM 300 via a remote ID signal at 404. The flight mission may comprise an expected flight path. The expected flight path may be available via a network remote ID. During the flight mission, online updates in the UTM 300 may also be used to refine the network remote ID functionality. The online updates may comprise, for example, changes on the flight path observed and approved by the UTM 300. [0093] At 406, the UAV 102 may be configured to start to actively detect relevant RF transmitters in the current region, which transmitters may cause interference along a flight path of the UAV 102. In an embodiment, the UAV 102 may be configured to select to sample RF channels co-located or adjacent to the current RF channels in-use at the UAV side. An increase on the overall received power observed over time series of any of the RF channels may trigger the next operations below. [0094] In an embodiment, the UAV 102 may be configured to monitor actively, e.g., via sampling, radio frequencies for increase in the received power over the time series. For example, the UAV 102 may be configured to scan radio and TV frequencies. The radio and TV channel frequencies may be relevant, as they typically use high transmit power, and the near-field (region where there are inductive and capacitive effects on the electromagnetic field) can extend for dozens of meter. Neighbor devices may be protected from this effects as the frequencies are usually transmitted by very high antennas. However, for a flying UAV 102 they may become more relevant. [0095] In an embodiment, in the detection phase at 406, the UAV 102 may be configured to monitor for a reception of a report of RF zones to be avoided in the region. The report may be received, for example, via a DAA signaling frame. The DAA signaling frame may be transmitted, for example, by other UEs (UAVs) or other NG-RAN nodes. The report may be received, for example, via 3GPP PC5 interface. [0096] The report may comprise information of at least one of an estimated location of a transmitter source, a location of a device that is reporting on the transmitter source, a direction of a transmission of the reported transmitter source, a frequency channel of the reported transmitter source, a start and stop time for the broadcast or a safe distance from the reported location of the transmitter source. [0097] In an embodiment, the UAV 102 may be configured to request a list of known relevant transmitters in the region from the serving NG-RAN 104. In an embodiment, the request may comprise a list of the relevant frequencies of the transmitters. In an embodiment, the request may be for persistent reporting where the NG-RAN 104 reports relevant transmitters along the flight route of the UAV 102. [0098] When potentially relevant transmitter sources are identified, the UAV 102 may be configured to locate, at 408, the position and/or direction of the transmitter source. The UAV 102 may be configured to locate a three- dimensional position of the transmitter. The localization may be done, for example, based on one or more of the following techniques: an angle of arrival estimation, a gradient of the received power along the flight route of the UAV 102, ranging via radar sensing (mmWave), LiDAR based light detection and ranging, video or image based detection and ranging, a request of help from NG-RAN to use NG-RAN and NG-RAN users radar sensing capabilities to refine the position of the transmitter, a request of NG-RAN database on relevant transmitters for a given radio frequency in the region, a request of a cloud-based database on relevant transmitters for a given radio frequency in the region, a request from NG- RAN for beam characteristics of the transmitter, and/or a request from core network for beam characteristics of the transmitter. [0099] The beam characteristics may comprise, for example, 3 dB bandwidth in azimuthal and elevation direction, or more detailed information with a first null and a first side lobe level. The beam characteristics may help the UAV 102 to determine whether the transmitter is relevant to the UAV 102 or not in its flight path. [00100] Based on the previously reported information and/or the information acquired by the UAV 102, at 410, the UAV 102 may be configured to estimate the impact of the transmitter source(s) along predicted waypoints in the flight path of the UAV 102. Hence, the UAV 102 may identify potentially dangerous zones, which zones may be three-dimensional, wherein the transmitter sources cause high interference with the UAV 102. [00101] In an embodiment, the UAV 102 may be configured to estimate an average noise or interference rise in its communication and/or adjacent channels due to at least one of the potentially relevant transmitter sources. Once the noise or interference rises above a certain threshold, the UAV 102 may be configured to flag it as a start of the RF zone to be avoided. Similarly, end of the RF zone may be established. The threshold may be UAV dependent as some UAV receivers have better rejection capabilities, i.e., better filters, from adjacent frequencies. The UAV 102 may be configured to take into account its antenna orientation in estimating impact of the transmitter source in identifying the RF zone. [00102] The UAV 102 may be configured to send a warning related to the potentially RF dangerous zones in the flight path to the UTM 300 and a UAV controller. At 412, the UAV 102 may be configured to send a notification to the UTM 300 comprising a report of the detected RF zone(s) to be avoided. In an embodiment, the notification comprising the RF zones may be requested by the NG-RAN 104 (at 414). At 416, the UAV 102 may send the notification report also to the NG-RAN 104. In an embodiment, the UAV 102 may be configured to perform a pre-defined safety protocol to avoid crossing the boundary of the RF zones. The UAV 102 may be also configured to share its antenna information in the report. The notification report may comprise at least one of an estimated position of the transmitter source, a direction (angular spread) of the transmitter source, a radius of the RF zone or a frequency of the transmission. [00103] At 418, the UAV 102 may be configured to start to broadcast a report of the RF zones to be avoided. The report may be transmitted, for example, via the DAA signaling. In an embodiment, the report may comprise (three-dimensional) antenna orientation and antenna height of the UAV 102. In an embodiment, the report may comprise a safe distance from the transmitter source for each receiver class. UAVs with better receivers may go closer to the transmitter. In an embodiment, the report may comprise a safe distance from the reported location of the transmitter source for a given antenna orientation of the UAV 102. In an embodiment, the report may comprise beam characteristics of the transmitter source. The beam characteristics may comprise, for example, a firs null and a first sidelobe level or other relevant beamwidth description. In an embodiment, the report may comprise a start and stop time for the broadcast. The provided time information may be used to indicate the time validity of the RF zone to be avoided by the UAVs. In an embodiment, the notification report and the broadcasted report may comprise the same information. [00104] FIG. 5 illustrates an example of an apparatus 500 configured to practice one or more example embodiments. [00105] The apparatus 500 may comprise at least one processor 502. The at least one processor 502 may comprise, for example, one or more of various processing devices, such as for example a co-processor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like. [00106] The apparatus 500 may further comprise at least one memory 504. The memory 504 may be configured to store, for example, computer program code 506 or the like, for example operating system software and application software. The memory 504 may comprise one or more volatile memory devices, one or more non-volatile memory devices, and/or a combination thereof. For example, the memory 504 may be embodied as magnetic storage devices (such as hard disk drives, magnetic tapes, etc.), optical magnetic storage devices, or semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.). [00107] The apparatus 500 may further comprise one or more communication interfaces 508 configured to enable the apparatus 500 to transmit and/or receive information, to/from other apparatuses. The communication interface 508 may be configured to provide at least one wireless radio connection, such as for example a 3GPP mobile broadband connection (e.g. 3G, 4G, 5G). However, the communication interface 508 may be configured to provide one or more other type of connections, for example a wireless local area network (WLAN) connection such as for example standardized by IEEE 802.11 series or Wi-Fi alliance; a short range wireless network connection such as for example a Bluetooth, NFC (near-field communication), or RFID connection; a wired connection such as for example a local area network (LAN) connection, a universal serial bus (USB) connection or an optical network connection, or the like; or a wired Internet connection. The communication interface 508 may comprise, or be configured to be coupled to, at least one antenna to transmit and/or receive radio frequency signals. One or more of the various types of connections may be also implemented as separate communication interfaces, which may be coupled or configured to be coupled to a plurality of antennas. [00108] The apparatus 500 may further comprise a user interface 510 comprising an input device and/or an output device. The input device may take various forms such a keyboard, a touch screen, or one or more embedded control buttons. The output device may for example comprise a display, a speaker, a vibration motor, or the like. [00109] When the apparatus 500 is configured to implement some functionality, some component and/or components of the apparatus 500, such as for example the at least one processor 502 and/or the memory 504, may be configured to implement this functionality. Furthermore, when the at least one processor 502 is configured to implement some functionality, this functionality may be implemented using program code 506 comprised, for example, in the memory 504. [00110] The functionality described herein may be performed, at least in part, by one or more computer program product components such as software components. According to an embodiment, the apparatus 500 comprises a processor 502 or processor circuitry, such as for example a microcontroller, configured by the program code when executed to execute the embodiments of the operations and functionality described. Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), application-specific Integrated Circuits (ASICs), application-specific Standard Products (ASSPs), System- on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), Graphics Processing Units (GPUs). [00111] The apparatus 500 comprises means for performing at least one method described herein. In one example, the means comprises the at least one processor 502, the at least one memory 504 including program code 506 configured to, when executed by the at least one processor 502, cause the apparatus 500 to perform the method. [00112] The apparatus 500 may comprise for example a computing device such as for example a base station, a network node, a server device, a client node, a user equipment, a mobile phone, a tablet computer, a laptop, a UAV, a drone, a vehicle, a UE mounted vehicle or the like. In one example, the apparatus 500 may comprise an unmanned aerial vehicle such as for example a drone. In an embodiment, the unmanned aerial vehicle may be mounted with at least one of a user equipment or a base station. Although the apparatus 500 is illustrated as a single device it is appreciated that, wherever applicable, functions of apparatus 500 may be distributed to a plurality of devices. [00113] FIG. 6 illustrates an example of a method 600 for detection and avoidance of one or more potential transmitter sources of interference according to an example embodiment. The method may be performed by a network node. [00114] At 602, the method comprises detecting a trigger to monitor and determine at least one radio frequency zone to be avoided by a flying unmanned aerial vehicle. [00115] At 604, the method comprises identifying at least one object by scanning in a main direction of boresight of one or more transmitters of the network node to determine the at least one radiofrequency zone to be avoided. The scanning may be performed, for example, via radar sensing. [00116] At 606, the method comprises causing broadcast of a report of the at least one radiofrequency zone to be avoided comprising at least one of an estimated location of the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast and/or a safety distance from the reported location of the transmitter. [00117] At 608, the method may comprise sending a notification report to an unmanned aircraft system traffic management server comprising information of the determined radiofrequency zone to be avoided. [00118] FIG. 7 illustrates an example of a method 700 for detection and avoidance of one or more potential transmitter sources of interference according to an example embodiment. The method may be performed by a user node, such as an unmanned aerial vehicle during flight. [00119] At 702, the method comprises obtaining information indicative of an area comprising at least one transmitter as a potential radiofrequency source of interference. [00120] At 704, the method comprises determining at least one of a position or a direction of the potential radiofrequency source of interference. [00121] At 706, the method comprises determining at least one radiofrequency zone to be avoided based on an average interference exceeding a threshold in a communication channel of the unmanned aerial vehicle due to the at least one transmitter. [00122] At 708, the method comprises sending a notification comprising information about the at least one radiofrequency zone to be avoided to at least one of an unmanned aircraft system traffic management server or a controller of the unmanned aerial vehicle. [00123] At 710, the method may comprise broadcasting a report of the at least one radiofrequency zone to be avoided. The report may be received, for example, from a UE or a base station. The report may be used as the indication of the area comprising at least one transmitter as a potential radiofrequency source of interference at 702. The report may comprise at least one of an estimated location of the transmitter source of interference, a direction of transmission of the reported transmitter source, a frequency channel of the transmitter source, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter source. [00124] Further features of the methods directly result from the functionalities and parameters of the apparatus 500, network nodes such as NG-RAN 104 and user nodes such as UAV 102 as described in the appended claims and throughout the specification and are therefore not repeated here. It is noted that one or more operations of the method may be performed in different order. [00125] An apparatus, for example a network node, a user node or a client node, may be configured to perform or cause performance of any aspect of the method(s) described herein. Further, a computer program may comprise instructions for causing, when executed, an apparatus to perform any aspect of the method(s) described herein. Further, an apparatus may comprise means for performing any aspect of the method(s) described herein. According to an example embodiment, the means comprises at least one processor, and memory including program code, the at one memory and the program code configured to, when executed by the at least one processor, cause performance of any aspect of the method(s). [00126] Any range or device value given herein may be extended or altered without losing the effect sought. Also, any embodiment may be combined with another embodiment unless explicitly disallowed. [00127] Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims. [00128] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item may refer to one or more of those items. [00129] The operations of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the scope of the subject matter described herein. Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought. [00130] The term 'comprising' is used herein to mean including the method, blocks, or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements. [00131] As used in this application, the term ‘circuitry’ may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable):(i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. [00132] As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device. [00133] It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from scope of this specification.

Claims

CLAIMS 1. A network node, comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer code configured to, with the at least one processor, cause the network node at least to: detect a trigger to monitor and determine at least one radiofrequency zone to be avoided by a flying unmanned aerial vehicle; identify at least one object in a main direction of boresight of one or more transmitters of the network node by performing radar sensing measurements to determine the at least one radiofrequency zone to be avoided; cause broadcast of a report of the at least one radiofrequency zone to be avoided comprising at least one of an estimated location of the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and send a notification report to an unmanned aircraft system traffic management server comprising information of the determined radiofrequency zone to be avoided. 2. The network node of claim 1, wherein the trigger is based on a reception of at least one of a remote identification signal broadcasted by an unmanned aerial vehicle, a report of a remote identification signal broadcasted by an unmanned aerial vehicle in an area, a request from the unmanned aircraft system traffic management server for safety measures alongside with a flight plan of one or more unmanned aerial vehicle, an indication of an unmanned aerial vehicle in the area based on a network remote identification, or a request from an unmanned aerial vehicle for radiofrequency zones to be avoided. 3. The network node of any preceding claims, wherein the trigger comprises an indication of a radio frequency or a subset of radio frequencies used by the unmanned aerial vehicle or relevant for monitoring, and the radar sensing measurements are performed only for the indicated frequencies. 4. The network node of any preceding claim, wherein the radar sensing measurements are performed across each of the one or more transmitters quasi-co-located with relevant transmitters of other network nodes determined based on previously reported locations of transmitters as sources of interference. 5. The network node of any preceding claim, wherein the at least one memory and the computer code configured to, with the at least one processor, cause the network node to: send a request to one or more user equipment to broadcast the report of the at least one radiofrequency zone to be avoided. 6. The network node of any preceding claim, wherein the radar sensing is performed in a given time interval having a start time and an end time determined by an entity which provided the trigger. 7. The network node of any preceding claim, wherein the report is broadcasted via detect-and-avoidance signaling format over an PC5 interface. 8. An unmanned aerial vehicle, comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer code configured to, with the at least one processor, cause the unmanned aerial vehicle at least to: obtain information indicative of an area comprising at least one transmitter as a potential source of interference along a flight plan of the unmanned aerial vehicle; determine at least one of a position or a direction of the at least one transmitter; determine at least one radiofrequency zone to be avoided based on an average interference exceeding a threshold in a communication channel of the unmanned aerial vehicle due to the at least one transmitter; and send a notification comprising information about the at least one radiofrequency zone to be avoided to at least one of an unmanned aircraft system traffic management server or a controller of the unmanned aerial vehicle. 9. The unmanned aerial vehicle of claim 8, wherein the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a reception of a report of a radiofrequency zone to be avoided comprising at least one of a location of a transmitter, a location of an entity reporting on the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and wherein the at least one memory and the computer code are further configured to, with the at least one processor, cause the unmanned aerial vehicle to broadcast the received report. 10. The unmanned aerial vehicle of any preceding claim, wherein the information indicative of an area comprising at least one transmitter as a potential source of interference is based on a request sent to a serving network node for a list of transmitters relevant for the flying unmanned aerial vehicle based on at least one of a radiofrequencies associated to the unmanned aerial vehicle or a flight plan of the unmanned aerial vehicle. 11. The unmanned aerial vehicle of any preceding claim, wherein the information indicative of areas comprising at least one transmitter as a potential source of interference is based on a detected increase on an overall interference power of radiofrequency channels associated with radiofrequency channels used by the unmanned aerial vehicle. 12. The unmanned aerial vehicle of any preceding claim, wherein at least one of the position or the direction is determined based on at least one of a gradient of the received power along a flight route of the unmanned aerial vehicle, a request of help from a network node to use the network node and network node users radar sensing capabilities to refine the position of the transmitter, a request for a network node database on relevant transmitters for a given radio frequency in the region, a request of a cloud-based database on relevant transmitters for a given radio frequency in the region, a request for a network node for beam characteristics of the transmitter, or a request for a core network for beam characteristics of the transmitter. 13. The unmanned aerial vehicle of any preceding claim, wherein the broadcasted report further comprises at least one of an orientation and height an antenna of the unmanned aerial vehicle, a receiver class specific safety distances, a safety distance from the reported location of the transmitter for a given antenna orientation of an unmanned aerial vehicle, or beam characteristics of the transmitter. 14. A method, comprising: detecting a trigger to monitor and determine at least one radiofrequency zone to be avoided by a flying unmanned aerial vehicle; identifying at least one object in a main direction of boresight of one or more transmitters of the network node by performing radar sensing measurements to determine the at least one radiofrequency zone to be avoided; causing broadcast of a report of the at least one radiofrequency zone to be avoided comprising at least one of an estimated location of the transmitter, a direction of transmission of the reported transmitter, a frequency channel of the transmitter, a start and stop time for the broadcast or a safety distance from the reported location of the transmitter; and sending a notification report to an unmanned aircraft system traffic management server comprising information of the determined radiofrequency zone to be avoided. 15. A method, comprising: obtaining information indicative of an area comprising at least one transmitter as a potential source of interference along a flight plan of the unmanned aerial vehicle; determining at least one of a position or a direction of the at least one transmitter; determining at least one radiofrequency zone to be avoided based on an average interference exceeding a threshold in a communication channel of the unmanned aerial vehicle due to the at least one transmitter; sending a notification comprising information about the at least one radiofrequency zone to be avoided to at least one of an unmanned aircraft system traffic management server or a controller of the unmanned aerial vehicle.