Methods, apparatuses and computer programs for a relay node and a wireless backhaul node

Abstract

Various examples of the present disclosure relate to methods for a mobile relay node in a cellular mobile communication system, to a corresponding apparatus for the mobile relay node that is configured to perform at least one of the methods for the mobile relay node, to a method for a wireless backhaul node in a cellular mobile communication system, to a corresponding apparatus for the wireless backhaul node that is configured to perform the method for the wireless backhaul node, and to corresponding computer programs. A method for a mobile relay node in a cellular mobile communication system comprises receiving (120), from a wireless backhaul node and / or a network entity, a reporting configuration and / or a request for information on at least one user equipment, UE, using or being attached to the mobile relay node, and providing (140), to the wireless backhaul node and / or a network entity, the information on the at least one UE according to the reporting configuration and / or in response to the request.

Description

[0001] 202407816 1

[0002] Methods, Apparatuses and Computer Programs for a Relay Node and a Wireless Backhaul Node

[0003] Description

[0004] Various examples of the present disclosure relate to methods for a mobile relay node in a cellular mobile communication system, to a corresponding apparatus for the mobile relay node that is configured to perform at least one of the methods for the mobile relay node, to a method for a wireless backhaul node in a cellular mobile communication system, to a corresponding apparatus for the wireless backhaul node that is configured to perform the method for the wireless backhaul node, and to corresponding computer programs.

[0005] Integrated access and backhaul (IAB) is a feature introduced by 3GPP (3rdGeneration Partnership Project, a standardization organization) in Release 15 and enhanced in subsequent releases to address the challenge of providing backhaul connectivity for next-generation wireless networks. IAB enables wireless relay nodes to use the same radio resources for both access links (connecting user devices) and backhaul links (connecting to the core network), eliminating the need for dedicated wired backhaul infrastructure. This is particularly valuable for dense urban deployments and areas where fiber installation is impractical or cost-prohibitive, allowing network operators to rapidly deploy small cells and expand coverage.

[0006] The IAB architecture comprises IAB nodes (relay nodes) and IAB donors (typically gNBs (next generation Node B) with wired backhaul connections). IAB nodes function as both base stations serving user equipment and as relay nodes forwarding traffic over wireless backhaul links to the donor node. The system supports multi-hop topologies where traffic can traverse multiple IAB nodes before reaching the donor node.

[0007] US20210084606A1 describes techniques for over-the-air synchronization in integrated access and backhaul communications, including methods where a network entity adjusts timing for communication between nodes based on a received timing adjustment factor. 202407816 2

[0008] US20210044958A1 relates to wireless communication technologies, specifically to the use and management of mobility state information for integrated access backhaul (IAB) nodes. It describes methods where wireless communication devices handle mobility state information, which may include parameters such as the mobility levels or changes in mobility of IAB nodes, to improve operations and transmission strategies.

[0009] US20220400427A1 describes methods, apparatus, and systems for minimizing signaling overhead in wireless systems by utilizing integrated access and backhaul indication information to maintain service continuity.

[0010] US20210068096A1 describes systems and methods for a mobile wireless node to communicate within a wireless backhaul network, and that use dynamically assigned communication resources during changes in the network topology.

[0011] W02024017909A1 describes a method in communication systems for requesting resources between source and target Integrated Access and Backhaul (IAB) topologies, involving transmitting a message from the source donor-CU to the target donor-CU with information about a specific lAB-node identified as a mobile lAB-node. The patent also covers a corresponding method at the target donor and the related devices.

[0012] US20220330196A1 describes methods and devices using a mobile IAB node to address issues related to terminal device operations causing TAU storms, with the method involving the use of received first TAC list information to initiate TAU procedures for terminal device location management.

[0013] Air taxis are (often electric) vertical takeoff and landing (eVTOL) aircraft designed to transport passengers over short to medium distances in urban environments. These autonomous or piloted vehicles aim to reduce traffic congestion and provide faster point-to-point transportation in cities. In some cases, the air taxis may integrate Integrated Access and Backhaul (IAB) nodes that would enable them to serve dual purposes as both transportation vehicles and mobile network infrastructure, extending wireless coverage and capacity. This scenario presents significant network 202407816 3 management challenges, including rapid topology changes due to vehicle mobility and frequent handovers.

[0014] There may be a desire for an improved concept for relay nodes, such as IAB nodes, integrated into moving vehicles, such as air taxis.

[0015] This desire is addressed by the subject matter of the independent claims.

[0016] Various examples of the present disclosure are based on the finding that in cellular mobile communication systems mobile relay nodes present unique challenges for network management and optimization. Mobile relay nodes, such as highly mobile IAB nodes, which may include relay nodes mounted on land vehicles, vessels, or aerial vehicles, such as aircraft or drones, can move through the network while providing connectivity to user equipment. This mobility creates challenges for wireless backhaul nodes and network entities in understanding and managing the user equipment connected to or attached to these mobile relay nodes, particularly with respect to handover and re-selection decisions, resource allocation, and quality of service provisioning. The proposed concept addresses these challenges by enabling mobile relay nodes to provide information about the user equipment that they serve to wireless backhaul nodes and network entities, thereby facilitating improved network management and optimization for mobile relay scenarios.

[0017] The proposed concept provides a coordinated approach for mobile relay nodes and wireless backhaul nodes to exchange information about user equipment served by the mobile relay nodes. By enabling wireless backhaul nodes to determine that a relay node is mobile, and to request or configure reporting of user equipment information, and by enabling mobile relay nodes to provide such information according to configured reporting or in response to requests, the proposed concept results in improved network awareness of the connectivity situation in mobile relay scenarios. This improves the ability of the network to make informed decisions regarding handover and re-selection procedures, resource allocation, and quality of service management. Furthermore, by enabling mobile relay nodes to inform user equipment that they are mobile, the proposed concept allows user equipment to adapt their behavior accordingly, which enhances overall system performance. 202407816 4

[0018] Some aspects of the present disclosure relate to a method for a mobile relay node in a cellular mobile communication system. The method comprises receiving, from a wireless backhaul node and / or a network entity, a reporting configuration and / or a request for information on at least one user equipment (UE) using or being attached to the mobile relay node. The method further comprises providing, to the wireless backhaul node and / or a network entity, the information on the at least one UE according to the reporting configuration and / or in response to the request. By enabling the mobile relay node to provide information on user equipment according to configured reporting or in response to requests, the proposed concept allows wireless backhaul nodes and network entities to gain visibility into the user equipment served by mobile relay nodes, which improves network management capabilities and enables more informed decisionmaking for handover, re-selection, resource allocation, and quality of service provisioning.

[0019] To enable efficient triggering of information reporting based on relay node mobility status, in various examples, the wireless backhaul node may first determine the mobility characteristics of the relay node before requesting information. For example, the request may be received in response to the wireless backhaul node determining that the mobile relay node is a mobile relay node. This ensures that information reporting is triggered specifically for mobile relay scenarios where such information is most valuable for network management.

[0020] In scenarios involving highly mobile relay deployments, the method may be particularly beneficial for mobile relay nodes with significant mobility characteristics. For example, the method may be performed by a moving and / or flying relay node. This addresses the unique challenges associated with mobile relay nodes that are airborne or otherwise in motion, where traditional static relay node management approaches may be insufficient.

[0021] To enable user equipment to adapt their behavior based on the mobility characteristics of their serving mobile relay node, in various examples, the mobile relay node may inform the user equipment of its mobility status. For example, the method may comprise providing information on the mobile relay node being a mobile relay node that is moving to at least one UE. This allows user equipment to adjust parameters such as mobility 202407816 5 procedures, measurements, and expectations regarding service continuity based on the knowledge that they are being served by a mobile relay node.

[0022] For enhanced clarity regarding the type of mobile platform hosting the mobile relay node, in various examples, the mobility information may include specific details about the vehicle type. Therefore, the information on the mobile relay node being a mobile relay node may indicate that the mobile relay node is one of a land vehicle, a vessel, or an aerial vehicle used for the transportation of passengers and / or goods and is moving. This enables user equipment to better understand the mobility patterns and characteristics they may experience while connected to the mobile relay node, and may influence the UE’s decision to use (or avoid) the mobile relay node.

[0023] To enable proactive triggering of information requests based on observed relay node behavior, in various examples, the mobile relay node may provide reports that indicate its mobility characteristics. For example, the method may comprise providing one or more reports to the wireless backhaul node and / or a network entity. The reporting configuration or request may be received in response to the one or more reports. This allows the wireless backhaul node or network entity to identify mobile relay nodes based on their reported characteristics and subsequently request detailed user equipment information.

[0024] For enhanced detection of relay node mobility through various measurement types, in various examples, the reports provided by the mobile relay node may include measurements that are particularly indicative of mobility. Therefore, the one or more reports may comprise at least one of a height report, a timing advance report, a flight path report, or a report on the received power of one or more downlink reference signals. These reports enable the wireless backhaul node or network entity to detect mobility patterns and characteristics of the mobile relay node.

[0025] To address challenges with distinguishing between user equipment traveling with the mobile relay node and user equipment temporarily connected to it, in various examples, the mobile relay node may analyze the relationship between user equipment and the mobile relay node. For example, the method may comprise determining which UE using or being attached to the mobile relay node is traveling with the mobile relay node. The 202407816 6 information on the at least one UE provided to the wireless backhaul node or the network entity may include information on which UE is traveling with the mobile relay node. By distinguishing traveling user equipment from temporarily connected user equipment, the proposed concept enables more appropriate handover as well as reselection decisions and resource management strategies.

[0026] For more granular differentiation of user equipment mobility characteristics, in various examples, the mobile relay node may provide separate information categories. Therefore, the information on the at least one UE provided to the wireless backhaul node or the network entity may include separate information on which UE is traveling with the mobile relay node and which UE is not traveling with the mobile relay node. This enables the wireless backhaul node or network entity to apply different management strategies for different categories of user equipment based on their mobility relationship with the mobile relay node.

[0027] To provide comprehensive information enabling informed network management decisions, the user equipment information may include various types of details in various examples. For example, the information on the at least one UE may comprise at least one of a number of UEs connected to or being attached to the mobile relay node, an identifier of the at least one UE, a capability of the at least one UE, a service used by the at least one UE, a bearer used by the at least one UE, data buffer status, or a load estimate that is based on current or history of data exchange. Such information enables the wireless backhaul node or network entity to make informed decisions regarding resource allocation, quality of service provisioning, handover and re-selection procedures. Moreover, the mobile relay node may act as middleman between UEs and network. It may need to buffer data locally, before forwarding to UEs (or to the network). The data buffer volume (or a load estimate) that is supposed to be forwarded to UEs that are not traveling with the mobile IAB node may be a useful indication to the next or target IAB node that will ..receive" the UEs that are not traveling with the mobile relay node and, thus, loosing their connection. Such an in-advance indication may help the target mobile relay node (e.g., target IAB node) to prepare / reserve radio resources (for a smooth transition) and the wireless backhaul node (e.g., IAB donor node, or network entity) to direct those UEs (not traveling) to the best target relay node nearby. 202407816 7

[0028] Some aspects of the present disclosure relate to a method for a mobile relay node in a cellular mobile communication system. The method comprises providing information on the mobile relay node being a mobile relay node that is moving to at least one User Equipment, UE. By informing User Equipment of the mobile nature of the relay node, the proposed concept enables User Equipment to adapt its behavior, measurements, and mobility procedures appropriately, which improves service continuity and user experience in mobile relay scenarios.

[0029] For enhanced clarity regarding the type of mobile platform hosting the mobile relay node, the mobility information provided to user equipment may include specific vehicle type details in various examples. Therefore, the information on the mobile relay node being a mobile relay node may indicate that the mobile relay node is one of a land vehicle, a vessel, or an aerial vehicle for the transportation of passengers and / or goods that is moving. This enables user equipment to better understand and predict the mobility patterns they may experience and may influence the UE’s decision to use or not use the mobile relay.

[0030] Some aspects of the present disclosure relate to a method for a wireless backhaul node in a cellular mobile communication system. The method comprises determining that a relay node is a mobile relay node. The method further comprises configuring the mobile relay node to report information on at least one UE and / or providing a request for information on at least one UE that is using or being attached to the mobile relay node to the mobile relay node. The method also comprises obtaining the information on the at least one UE according to the configured reporting and / or in response to the request. By determining relay node mobility, configuring reporting or requesting information, and obtaining user equipment information, the proposed concept enables the wireless backhaul node to gain visibility into the user equipment served by mobile relay nodes, which facilitates improved handover and re-selection decisions, resource allocation, and quality of service management.

[0031] To enable mobility detection based on reports provided by the relay node, in various examples, the wireless backhaul node may analyze reports from the relay node to identify mobility characteristics. For example, the act of determining that the relay node is a mobile relay node may comprise receiving one or more reports from the relay node, 202407816 8 the one or more reports being indicative of the relay node being a mobile relay node. This allows the wireless backhaul node to identify mobile relay nodes based on their reported behavior and characteristics.

[0032] For enhanced detection of relay node mobility through specific measurement types, in various examples, the reports indicative of mobility may include particular types of measurements. Therefore, the one or more reports being indicative of the relay node may comprise at least one of a height report, a timing advance report, a flight path report, or a report on the received power of one or more downlink reference signals. These specific report types enable effective identification of mobile relay nodes based on measurement patterns characteristic of mobility. Additionally, or alternatively, the wireless backhaul node may evaluate one or more uplink positioning reference signals emitted by the mobile relay node to determine whether or that the relay node is a mobile relay node. These uplink positioning reference signals may allow the network to more easily track the mobile relay node’s motion.

[0033] To address challenges with detecting relay node mobility through analysis of radio characteristics, the wireless backhaul node may, in various examples, monitor changes in various radio parameters associated with the relay node. For example, determining that the relay node is a mobile relay node may comprise detecting movement of the relay node based on changes in at least one of: beamforming information, fulldimension multiple input multiple output (FD-MIMO) feedback information, timing advance values, Doppler shift, time of arrival, time difference of arrival, or angle of arrival measurements associated with the relay node (e.g., of the aforementioned uplink positioning reference signals). By analyzing changes in these radio parameters, the proposed concept enables detection of relay node mobility even without explicit mobility reports from the relay node.

[0034] To improve mobility management in mobile relay scenarios, in various examples, the wireless backhaul node may utilize the obtained user equipment information for handover- and re-selection-related decisions. For example, the method may comprise performing at least one action related to handover or re-selection based on the information on the at least one UE. This enables more informed and effective mobility 202407816 9 procedures that account for the specific characteristics and requirements of user equipment served by mobile relay nodes.

[0035] For enhanced resource management and quality of service provisioning for mobile relay nodes, in various examples, the wireless backhaul node may configure the mobile relay node based on the obtained user equipment information. Therefore, the method may comprise configuring the mobile relay node with respect to at least one of the radio resources to be used or Quality of Service, QoS, requirements. This enables dynamic adaptation of relay node configuration based on the user equipment load and service requirements.

[0036] To enable flexible and efficient reporting mechanisms tailored to different scenarios, the wireless backhaul node may configure reporting triggers for the relay node, in various examples. For example, the relay node may be configured with respect to at least one of a triggering condition, criterion, or threshold for providing the information on at least one user equipment, UE. This allows the reporting behavior to be adapted to specific network requirements and mobility patterns.

[0037] For enhanced flexibility in reporting mechanisms, in various examples, the configured triggering conditions may support different reporting modes. Therefore, the triggering condition, criterion, or threshold may trigger at least one of event-based reporting or periodic reporting by the mobile relay node. This enables both reactive reporting based on specific events and proactive periodic reporting depending on network requirements.

[0038] Some examples of the present disclosure relate to a second method for the wireless backhaul node in a cellular mobile communication system. The second method comprises obtaining the information on the at least one UE using or being attached to a mobile relay node from the mobile relay node. The second method comprises performing the at least one action related to handover or re-selection based on the information on the at least one UE. This enables more informed and effective mobility procedures that account for the specific characteristics and requirements of user equipment served by mobile relay nodes. For example, this second method may comprise one or more additional features of the (first) method for the wireless backhaul node as described above. 202407816 10

[0039] In various examples, the proposed concept may be implemented in integrated access and backhaul architectures. For example, the method for the mobile relay node may be performed by an integrated access and backhaul node, and / or the methods for the wireless backhaul node may be performed by an integrated access and backhaul donor node. This enables application of the proposed concept in integrated access and backhaul deployments where relay functionality is combined with access functionality.

[0040] Some aspects of the present disclosure relate to a computer program having a program code for performing the methods described herein when the computer program is executed on a computer, a processor, or a programmable hardware component. This enables software-based implementation of the proposed concept on various computing platforms.

[0041] Some aspects of the present disclosure relate to an apparatus for a mobile relay node in a cellular mobile communication system. The apparatus comprises one or more interfaces configured to communicate in the cellular mobile communication system. The apparatus further comprises one or more processing devices configured to perform at least one of the methods described herein for the mobile relay node. This provides a hardware implementation of the relay node functionality for mobile relay scenarios.

[0042] Some aspects of the present disclosure relate to an apparatus for a wireless backhaul node (e.g., an IAB donor node) in a cellular mobile communication system. The apparatus comprises one or more interfaces configured to communicate in the cellular mobile communication system. The apparatus further comprises one or more processing devices configured to perform the method for the wireless backhaul node as described herein. This provides a hardware implementation of the wireless backhaul node functionality for managing mobile relay nodes and obtaining user equipment information.

[0043] Some examples of apparatuses and / or methods will be described in the following, by way of example only, and with reference to the accompanying figures, in which: 202407816 11

[0044] Fig. 1a shows a schematic diagram of a cellular mobile communication system comprising a mobile relay node, a wireless backhaul node and one or more UEs;

[0045] Fig. 1 b shows a flowchart of methods for a mobile relay node;

[0046] Fig. 2 shows a flowchart of a method for a wireless backhaul node;

[0047] Fig. 3 shows a flowchart of operations for a mobile IAB node (mobile relay node, such as an air taxi) for a first mechanism, in which the MT part of the IAB node has UAV capabilities;

[0048] Fig. 4 shows a flowchart of operations for an IAB donor node (wireless backhaul node) for the first mechanism, in which the MT part of the IAB node has UAV capabilities;

[0049] Fig. 5 shows a flowchart of operations for a mobile IAB node (mobile relay node, such as an air taxi) for a second mechanism, in which the MT part of the IAB node does not have UAV capabilities; and

[0050] Fig. 6 shows a flowchart of operations for an IAB donor node (wireless backhaul node) for the second mechanism, in which the MT part of the IAB node does not have UAV capabilities.

[0051] Some examples are now described in more detail with reference to the enclosed figures. However, other possible examples are not limited to the features of these embodiments that are described in detail. Other examples may include modifications of the features, as well as equivalents and alternatives to the features. Furthermore, the terminology used herein to describe certain examples should not be restrictive of further possible examples.

[0052] Throughout the description of the figures, same or similar reference numerals refer to the same or similar elements and / or features, which may be identical or implemented in 202407816 12 a modified form while providing the same or a similar function. The thickness of lines, layers, and / or areas in the figures may also be exaggerated for the sake of clarification.

[0053] When two elements A and B are combined using an “or”, this is to be understood as disclosing all possible combinations, i.e. , only A, only B, as well as A and B, unless expressly defined otherwise in the individual case. As an alternative wording for the same combinations, "at least one of A and B" or "A and / or B" may be used. This applies equivalently to combinations of more than two elements.

[0054] If a singular form, such as “a”, “an”, and “the” is used and the use of only a single element is not defined as mandatory either explicitly or implicitly, further examples may also use several elements to implement the same function. If a function is described below as implemented using multiple elements, further examples may implement the same function using a single element or a single processing entity. It is further understood that the terms "include", "including", "comprise", and / or "comprising", when used, describe the presence of the specified features, integers, steps, operations, processes, elements, components, and / or a group thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components, and / or a group thereof.

[0055] Fig. 1a illustrates block diagrams of examples of apparatuses 10 and 20 for a mobile relay node 100, such as a mobile IAB node, and a wireless backhaul node 200, such as an IAB donor node. The apparatus 10 for the mobile relay node 100 comprises one or more interfaces 12 (shown as wireless transceiver 12) to communicate in the cellular mobile communication system, one or more processing devices 14 (shown as processor 14), and a memory 16. The one or more processing devices 14 are coupled with the one or more interfaces 12 and the memory 16. The one or more processing devices 14 are configured to perform a method for the mobile relay node, as shown in Fig. 1 b. In Fig. 1a, the apparatus 10 is shown to be part of a mobile relay node 100, which is considered optional with respect to the apparatus 10.

[0056] Fig. 1 b shows a flowchart of two methods for a mobile relay node, which may either or both be performed by the apparatus. The first method comprises receiving 120 from the wireless backhaul node 200 and / or a network entity (via the wireless backhaul node and 202407816 13 optionally one or more intermediate backhaul nodes), a reporting configuration and / or a request for information on at least one user equipment (UE) using or being attached to the mobile relay node. Ultimately, the core network of the mobile communication system may trigger this reporting configuration or request, e.g., for managing air traffic, UAV mobility, and resources. The first method comprises providing 140 to the wireless backhaul node and / or a network entity the information on the at least one UE according to the reporting configuration and / or in response to the request. Ultimately, the information on the UE may reach the core network, e.g., the Access and Mobility Management Function in case of a 5G network. The second method, which may be included in the first method, comprises providing 150 information on the mobile relay node being a mobile relay node that is moving to at least one UE 30. For example, the methods may be performed by the mobile relay node (e.g., by an IAB node).

[0057] The apparatus 20 for the wireless backhaul node comprises one or more interfaces 22 (shown as wireless transceiver 22) to communicate in the cellular mobile communication system, one or more processing devices 24 (shown as processor 24), and a memory 26. The one or more processing devices 24 are coupled with the one or more interfaces 22 and the memory 26. The one or more processing devices 24 are configured to perform a method for the wireless backhaul node, as shown in Fig. 2. In Fig. 1a, the apparatus 20 is shown to be part of a wireless backhaul node 200, which is considered optional with respect to the apparatus 20. Alternatively, the apparatus 20 may be part of a network entity of the core network (e.g., the AMF).

[0058] Fig. 2 shows a flowchart of two methods for the wireless backhaul node 200. The first method comprises determining 220 that the relay node 100 is a mobile relay node. The first method comprises at least one of a) configuring 230 the mobile relay node to report the information on at least one UE, or b) providing a request to the mobile relay node for the information on the at least one UE that is using or is attached to the mobile relay node. The first and second method comprise obtaining 240 the information on the at least one UE according to the configured reporting and / or in response to the request. The second method comprises performing 250 at least one action related to handover or re-selection based on the information on the at least one UE. For example, the second method may further comprise one or more features discussed in connection with the first method. For example, the methods of Fig. 2 may be performed by the 202407816 14 wireless backhaul node 200 (e.g., an IAB donor node) or by a network entity of the core network (e.g., the AMF).

[0059] The one or more interfaces 12, 22 may serve as an interface for communicating within the communication system. The one or more interfaces 12, 22 may correspond to one or more inputs and / or outputs for receiving and / or transmitting information, which may be in digital (bit) values or analog according to a specified code or protocol, within a module, between modules, or between modules of different entities. For example, an interface may comprise interface circuitry configured to receive and / or transmit information. In examples, an interface may comprise any means for obtaining, receiving, transmitting, or providing analog or digital signals or information, e.g., any connector, contact, pin, register, input port, output port, conductor, lane, etc., which allows providing or obtaining a signal or information. The one or more interfaces 12, 22 may be configured to communicate (transmit, receive, or both) in a wireless and / or wired manner, and they may be configured to communicate, i.e. , transmit and / or receive signals or information with further internal or external components. The one or more interfaces 12, 22 or the apparatuses 10, 20 may comprise further components to enable communication in a (mobile) communication system or network; such components may include transceiver (transmitter and / or receiver) components, such as one or more Low- Noise Amplifiers (LNAs), one or more Power-Amplifiers (PAs), one or more duplexers, one or more diplexers, one or more filters or filter circuitry, one or more converters, one or more mixers, accordingly adapted radio frequency components, one or more antennas, etc. For example, the respective one or more interfaces 12, 22 may enable radio communication with UEs and communication between nodes, which can be directly and / or indirectly, wired and / or wireless, respectively.

[0060] The one or more processing devices 14, 24 may be implemented using one or more processing units, one or more circuits, or any means for processing, such as a processor, a computer, or a programmable hardware component being operable with accordingly adapted software. In other words, the described function of the one or more processing devices 14, 24 may as well be implemented in software, which is then executed on one or more programmable hardware components. Such hardware components may comprise a general-purpose processor, a Digital Signal Processor (DSP), a micro-controller, etc. 202407816 15

[0061] In at least some embodiments, the memory 16, 26 may comprise at least one element of the group of a computer readable storage medium, such as an magnetic or optical storage medium, e.g. a hard disk drive, a flash memory, Floppy-Disk, Random Access Memory (RAM), Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), an Electronically Erasable Programmable Read Only Memory (EEPROM), or a network storage.

[0062] In examples, the wireless backhaul node 200 provides a wireless backhaul connection to the mobile relay node 100 (while having itself a wired or wireless backhaul connection to the core network). For example, the wireless backhaul node 200 may be implemented by a terrestrial or non-terrestrial base station, such as a gNodeB, of the mobile communication system. The wireless backhaul node 200 may belong to an access network of the cellular mobile communication system, while the network entity, which may be the AMF, may be part of the core network of the mobile communication system. The wireless backhaul node 200 may communicate with the network entity, e.g., forward the reporting configuration or request of the network entity to the mobile relay node, and forward the information on the at least one UE to the network entity.

[0063] The wireless backhaul node 200 may generate cells of a cellular system. The wireless backhaul node may correspond to a remote radio head, a transmission point, an access point, a macro cell, a small cell, a micro cell, a pico cell, a femto cell, or a metro cell. The term small cell may refer to any cell smaller than a macro cell, e.g., a micro cell, a pico cell, a femto cell, or a metro cell. A base station can be a wireless interface of a wired network, which enables transmission and reception of radio signals to a communication device. Such a radio signal may comply with radio signals, for example, standardized by 3GPP or, generally, be in line with one or more of the above-listed systems. Thus, the wireless backhaul node 200 may be a base station and may correspond to a NodeB, an eNodeB, an ngNB, a gNB, a BTS (Base Transceiver Station), or an access point, all of which may be implemented in a satellite, plane, HAPS, etc. In case of a moving implementation in a satellite, an airplane, etc., the link towards a core network of the communication system may also be implemented in a wireless manner. 202407816 16

[0064] The mobile communication system is hence cellular. The term cell refers to a coverage area of radio services provided by a transmission point, a remote unit, a remote head, a remote radio head, communication device, network entity, or a NodeB, an eNodeB, an ngNB, a gNB, a beam, or a satellite, respectively. The terms cell and base station may be used synonymously; a base station may generate multiple cells. A wireless communication device, e.g., at least one UE 30, can be registered or associated with at least one cell (e.g., the wireless backhaul node / base station); e.g., it can be associated with a cell such that data can be exchanged between the network and the mobile in the coverage area of the associated cell using a dedicated channel, connection, or link.

[0065] In various examples, the mobile relay node 100 is an IAB node and the wireless backhaul node is an IAB donor node (or equivalent nodes in subsequent versions of a cellular connectivity standard of the 3GPP). In summary, an IAB node is a radio access network (RAN) node that provides wireless connectivity to UEs and wirelessly backhauls access traffic. The IAB donor serves as the RAN node that provides the interface to the core network for UEs and delivers wireless backhaul functionality to the connected IAB nodes.

[0066] Integrated Access and Backhaul (IAB) Architecture 1a, as described in 3GPP TS 38.174: “NR; Integrated Access and Backhaul (IAB) radio transmission and reception” and 3GPP TS 38.472: “NG-RAN; F1 signalling transport”, enables both IAB nodes and UEs to connect in stand-alone mode to the next generation core (NGC). Each IAB node comprises a Distributed Unit (DU) and a Mobile Termination (MT). A DU is a logical node that includes a subset of the gNB (Next Generation Node B) functions, i.e. , functions of a base station, and terminates the radio protocol stack, controlling the operation of one or more RUs (Radio Units). The MT is the component that provides the radio transmission capabilities and terminates the radio interface for a UE (User Equipment). The MT allows the IAB node to connect upstream, either to another IAB node or directly to the IAB donor. The DU, on the other hand, is responsible for establishing RLC (Radio Link Control) channels to UEs and to the MTs of downstream IAB nodes.

[0067] An IAB node can maintain connections to multiple upstream IAB nodes or lAB-donor

[0068] DUs. Additionally, an IAB node may contain several DUs. Each DU within an IAB node 202407816 17 may have an F1-C connection (the control plane interface between the gNodeB Central Unit and gNodeB Distributed Unit) only with a single IAB donor CU-CP (Centralized Unit Control Plane). The IAB donor itself is equipped with a DU to support both UEs and MTs of downstream IAB nodes. Furthermore, the IAB donor holds the Centralized Unit (CU) for the DUs of all associated lAB-nodes as well as its own DU.

[0069] It is generally assumed that the DUs on an IAB node are served by only one IAB donor, though the donor may change as the network topology adapts. Each DU on an IAB node connects to the CU in the lAB-donor using a modified F1 interface, referred to as F1* The F1*-U protocol (the user plane interface between the IAB node's DU and the lAB-donor's DU, used for transporting user data over the backhaul link) operates over RLC channels on the wireless backhaul, linking the MT on the serving lAB-node with the DU on the donor. An adaptation layer is introduced to manage routing information, enabling hop-by-hop forwarding and replacing the IP functionality typically present in the standard F1 protocol stack.

[0070] In the context of the present disclosure, a UE using the mobile relay node is a UE that is attached to the mobile relay node (e.g., the IAB node) and that actively communicates with the mobile relay node. A UE that is merely attached to the mobile relay node without actively using the mobile relay node is a UE that is “only” attached to the mobile relay node. The information on the at least one UE may include information on connected UEs, including UEs in all possible RRC states (idle, inactive, connected).

[0071] Generally, the UE 30 may be a communication device that is capable of communicating wirelessly. In particular, however, the UE may be a mobile communication device, e.g., a communication device that is suitable for being carried around by a user. For example, the UE may be a User Terminal (UT) or UE within the meaning of the respective communication standards being used for mobile communication. For example, the UE may be a mobile phone, such as a smartphone, or another type of mobile communication device, such as a computer, a laptop computer, a tablet computer, a wearable device, and so on.

[0072] For example, the UE 30, the mobile relay node 100 and the wireless backhaul node 200 may be configured to communicate in a cellular mobile communication system. 202407816 18

[0073] Accordingly, the UE, the mobile relay node and the wireless backhaul node may be configured to communicate in a cellular mobile communication system, for example in a Sub-6GHz-based cellular mobile communication system (covering frequency bands between 400 MHz and 7 GHz), in a mmWave-based cellular mobile communication system (covering frequency bands between 24 GHz and 71 GHz), or in the so-called mid-bands (covering frequency bands between 7 GHz and 24 GHz). For example, the UE, the mobile relay node and the wireless backhaul node may be configured to communicate in a mobile communication system / cellular mobile communication system.

[0074] In general, the mobile communication system may, for example, correspond to one of the 3GPP-standardized mobile communication networks, where the term mobile communication system is used synonymously with mobile communication network. The mobile communication system may correspond to, for example, a 6th Generation system (6G), a 5th Generation system (5G), a New Radio (NR) system, a Long-Term Evolution (LTE), an LTE-Advanced (LTE-A), High Speed Packet Access (HSPA), a Universal Mobile Telecommunication System (UMTS) or a UMTS Terrestrial Radio Access Network (UTRAN), an evolved-UTRAN (e-UTRAN), a Global System for Mobile communications (GSM) or Enhanced Data rates for GSM Evolution (EDGE) network, a GSM / EDGE Radio Access Network (GERAN), or mobile communication networks with different standards, for example, generally an Orthogonal Frequency Division Multiple Access (OFDMA) network, a Time Division Multiple Access (TDMA) network, a Code Division Multiple Access (CDMA) network, a Wideband-CDMA (WCDMA) network, a Frequency Division Multiple Access (FDMA) network, a Spatial Division Multiple Access (SDMA) network, etc.

[0075] The proposed concept relates to methods and apparatuses for updating attached UE information for aerial and mobile relay nodes, such as IAB nodes. In particular, the proposed concept relates to a mobile relay node (such as a mobile IAB node), which is capable of providing wireless access to users as well as providing wireless backhaul in the same spectrum. Various examples may relate to an aerial mobile relay node / IAB (mlAB) node, which may be used in an air taxi in future urban air mobility use cases.

[0076] When an air taxi is used for urban air mobility, i.e. , to transfer people or cargo from one place to another, it requires connectivity to the terrestrial network. If the air taxi is a 202407816 19 mobile relay node (e.g., a mlAB) node, it can provide wireless access to both users inside the air taxi that are flying along with it, as well as users that connect to it from outside the air taxi, e.g., users on the ground which may see higher signal strength from the air taxi mlAB node, or other flying drones that see strong received signal power from the air taxi mlAB node. In this scenario, it may be beneficial to provide information to the wireless backhaul node (e.g., IAB donor, which may be a terrestrial base station) about the user equipment (UE) connecting to the aerial mlAB node in order to handle handovers as well as re-selections and perform resource allocation more efficiently.

[0077] In general, within 3GPP standardization, mechanisms are being discussed to identify UEs that are flying. For example, 3GPP study item TR 36.777 addresses various approaches for identifying airborne User Equipment (UE) in cellular networks. These approaches can be categorized into UE-based solutions, network-based solutions, and certification / license-based identification methods. For UE-based solutions, the UE can indicate its airborne status either explicitly or implicitly. Explicit indication methods include using an in-flight mode indication, providing altitude information, or transmitting location information. Implicit indication can be achieved by utilizing an enhanced measurement reporting mechanism, such as the introduction of new events that are characteristic of aerial operation. Network-based solutions rely on the network's ability to detect an airborne UE based on mobility history reports and patterns. A flying UE typically exhibits different handover characteristics compared to ground-based UEs, such as less frequent handovers or handovers to faraway target cells. These distinctive patterns enable the network to identify aerial UEs without explicit indication from the device. Aerial UE identification based on certification and license involves multiple signaling mechanisms. A UE indicates its support of UAV-related functions to the eNB through radio capability indication, which the eNB can use to identify that the UE supports UAV-related LTE functions. Additionally, permission for a UE to function as an aerial UE in the 3GPP network can be identified via subscription information, which may be passed to the eNB via S1 signaling from the MME. The eNB can combine this subscription information with the capability indication to identify an aerial UE, perform necessary control functions, and apply relevant operational parameters. It should be noted that the actual aerial usage certification, license, or limitation of a UE and how it is reflected in the subscription information falls outside the scope of RAN2 and may be provided from 3GPP or non-3GPP nodes to a 3GPP node. 202407816 20

[0078] Moreover, 3GPP Release 15 specifications introduced several key features to support Unmanned Aerial Vehicles (UAVs) in cellular networks. These features include interference detection based on measurement reporting, which is triggered when a configured number of cells fulfill the triggering criteria. Height and location reporting capabilities were implemented based on events where the UE's altitude crosses a network-configured threshold altitude. Additional features introduced in Release 15 include a UE-specific fractional path-loss compensation factor for uplink (UL) power control, which allows for more precise power management in aerial scenarios. The specifications also enable signaling of flight path information from the UE to the network, providing the network with predictive information about the UAV's intended trajectory. Furthermore, Release 15 introduced subscription-based aerial UE identification and authorization mechanisms to ensure proper control and management of UAVs operating within the cellular network.

[0079] In one TR related to Release 15 specifications, several UE capabilities related to aerial operation were discussed, organized across different parameter categories. Under physical layer parameters, a field was proposed to define whether the UE supports UE- specific uplink power control, which is useful for managing transmission power in aerial scenarios. Within the measurement parameters category, one extension field was proposed to specify whether the UE supports measurement reporting triggered based on a number of cells, enabling enhanced interference detection. A height measurement field defines whether the UE supports height-based measurement reporting as specified in TS 36.331 . Under other parameters, a flight plan field was proposed to define whether the UE supports reporting of the flight path plan through the procedure defined in TS 36.331 . This capability allows the UE to communicate its intended trajectory to the network for improved resource management and interference mitigation.

[0080] Identifying the flying state of a UAV by the network is important for several reasons. In some countries, such identification is required by regulations to ensure compliance with aviation and telecommunications rules. Additionally, the network uses this information to effectively control its resources and perform critical functions such as interference detection and mitigation, as well as adapting measurement configurations to accommodate the unique characteristics of aerial UEs. The functionality available to 202407816 21 support flying mode detection by a UE varies depending on whether the UE has subscription-based aerial UE authorization. For UEs with aerial authorization, functionalities such as height reporting, RSRP measurements for multiple cells, legacy RSRP, and timing advance are supported by default. FD-MIMO support in these UEs depends on their individual capabilities. In contrast, UEs without aerial authorization only support height reporting, RSRP for multiple cells, and FD-MIMO if they possess the necessary capabilities, while legacy RSRP and timing advance are supported regardless of authorization status.

[0081] Currently, flying mode detection is applicable only to UAV UEs with specific capabilities. However, passenger UEs on air taxis will not have such capabilities, since they are generally not UAV UEs. The air taxi may be an IAB node which provides connectivity to passenger UEs and potentially other UEs, and is connected to an IAB donor node (e.g., terrestrial base station) to provide backhaul to the UEs connected to it. It may be desirable for the network to get information about both the passenger UEs and the nonpassenger UEs connected to the air taxi IAB node, so that the network can optimize resource allocation, handle mobility, etc., more effectively.

[0082] The proposed concept introduces a new information update by the mobile relay node (e.g., mlAB node) to the wireless backhaul node (e.g., IAB donor) which may include the identity of the UEs connected to the mobile relay node, and mobility information of UEs that are connected to it but not moving along with the mobile relay node. In the proposed concept, a new information message (the information on the at least one UE) is defined for the mobile relay node (e.g., the IAB node DU) whereby it can report to the wireless backhaul node (e.g., the IAB-CU) and / or the network about the UEs connected to it which are in flying mode (or traveling with it) and about UEs that are not traveling with it. The information about flying / non-flying UEs connected to the mobile relay node helps in improving service for all the UEs, especially during handovers. Various examples of the proposed concept provide options for both cases, i.e. , the case in which the mobile relay node (e.g., the IAB-MT) has UAV UE capabilities, and the case in which the mobile relay node does not have UAV UE capabilities. The proposed concept provides enhancements for mobile relay node operation when the mobile relay node is an air taxi serving both UEs in the air taxi and possibly UEs outside the air taxi. It may be relevant for future enhancements of mlAB operation in 3GPP. It provides new 202407816 22 information / messages to be exchanged between a wireless backhaul node (e.g., IAB donor) and a mobile (flying) relay node (e.g., IAB node) to enable smoother operation when the mobile IAB node serves both users flying with it and users outside it.

[0083] While other systems provide a mechanism that involves transmitting information about a mlAB node to a base station including group mobility information, this information does not include or consist of information about UEs attached to the mlAB node or their status (whether airborne or otherwise), which is the subject of this ID. An indication of whether an IAB node is a mobile IAB node or not may not be sufficient to differentiate between the UEs that are connected to it and moving with the mlAB node and the UEs that are connected to it but not moving with the mlAB node. Such group mobility capability of the mlAB MT may be used to handle mobility of UEs that are connected to the mlAB and moving along with it. However, to handle mobility of other UEs that are connected to it but not moving along with it, such a group mobility capability is not sufficient.

[0084] In the proposed concept, it is assumed that all UEs traveling with the mobile relay node (e.g., the passengers of the air taxi) connect to the mobile relay node (e.g., the IAB-DU) in which they are traveling for wireless access. A new information message (the information on at least one UE) is defined for the mobile relay node (e.g., the IAB-DU) whereby it can report to the wireless backhaul node (e.g., IAB-CU) and / or the network. This information message may include information on the UEs connected to it that are in flying mode (or traveling with it) and information on UEs that are not traveling with it.

[0085] This information message is provided upon configuration or request by the network (e.g., provided by or via the wireless backhaul node). In other words, the wireless backhaul node / network entity configures or requests the mobile relay node to provide the information on the at least one relay node, e.g., in response to the wireless backhaul node / network entity determining that the mobile relay node is mobile, i.e. , traveling at non-negligible speeds (e.g., at least 10 km / h). In particular, the wireless backhaul node / network entity may configure or request the mobile relay node to provide the information on the at least one relay node upon determining that the mobile relay node is actively moving, e.g., upon determining that the mobile relay node is flying. Thus, the method of Fig. 1 b may be performed by a moving and / or flying relay node. 202407816 23

[0086] In some examples, the wireless backhaul node or network entity may request the information on the at least one UE, e.g., upon determining that the mobile relay node is moving. For example, the wireless backhaul node may provide periodic or aperiodic requests to the mobile relay node to provide the information on the at least one UE. Alternatively, or additionally, the network may configure the mobile relay node to automatically report the at least one UE. In particular, the mobile relay node may be configured with respect to at least one of a triggering condition, criterion, or threshold for providing the information on the at least one UE. The mobile relay node may evaluate the triggering condition, criterion, or threshold, and send the information on the at least one UE when or whenever the condition, criterion, or threshold is met.

[0087] For example, the triggering condition, criterion, or threshold may trigger at least one of event-based reporting or periodic reporting by the mobile relay node. In other words, the reporting by the mobile relay node (e.g., the IAB node DU) may be configured by the wireless backhaul node (e.g., IAB donor) in a periodic or aperiodic manner.

[0088] Alternatively, or additionally, the reporting may also be triggered by the air taxi IAB node itself, based on certain events, some examples of which are given below: For example, the reporting may be triggered before and after take-off: e.g., before the take-off operation starts, and after the aircraft reaches a stable altitude according to its initial flight path. For example, the reporting may be triggered before and after landing: e.g., before the landing operation starts while the aircraft is still at stable altitude, and right after the landing has completed and the aircraft is on the ground. For example, the reporting may be triggered before and after altitude change, e.g., before the altitude of the aircraft changes from the one specified in the initial flight path and after this altitude change is completed, and / or before and after the altitude changes more than a configured / specified threshold. For example, the reporting may be triggered before and after change in initial flight path: e.g., before and after the flight path (route, direction, speed, etc.) changes due to any reason

[0089] Additionally, the mobile relay node (e.g., the air taxi, IAB node-DU) may also transmit an indication that it is an airborne mobile IAB node, so that UEs not traveling with it may choose to connect to it or not based on this indication. In other words, the method for the mobile relay node (of Fig. 1 b) may comprise providing 150 information on the mobile 202407816 24 relay node being a mobile relay node that is (actively) moving to at least one UE. In particular, the information on the mobile relay node being a mobile relay node may indicate that the mobile relay node is one of a land vehicle, a vessel , or an aerial vehicle for the transportation of passengers and / or goods that is actively moving.

[0090] To enable the network to improve handover and re-selection behavior, resource management and QoS of the UEs, the mobile relay node (e.g., the IAB-DU) may determine which UEs are traveling (e.g., flying) along with it, e.g., using the timing advance values from those UEs, or other means, which is up to implementation. For example, in the case of an air taxi, at lift-off, reporting may be triggered and the mobile relay node (e.g., IAB node) may provide a list of UEs, comprising UEs traveling with it and a list of UEs not traveling with it. The list of UEs not traveling with the mobile relay node can be used by the network to anticipate how many (new) UEs need to be “on-boarded”, since ongoing connections to the mobile relay node will drop soon. The mobile relay node may proactively trigger a handover (RRC re-configuration) to another (local, stationary) base station or relay node (e.g., IAB node) to ensure service continuity, or re-configure or release its connections with “re-direction information” (in the RRC release message), e.g., cell IDs of local, stationary IAB nodes, which they can re-select.

[0091] Accordingly, the method of Fig. 1b (for the mobile relay node) may comprise determining 130 which UE that is using or being attached to the mobile relay node is traveling with the mobile relay node (and which is not). The mobile relay node (e.g., lAB-node MT) may then transmit this information (obtained from the lAB-node DU) to the wireless backhaul node (e.g., lAB-donor) on the ground. Thus, the information on the at least one UE provided to the wireless backhaul node or the network entity may include information on which UE is traveling with the mobile relay node. In particular, the information on the at least one UE may distinguish between UE that is traveling with the mobile relay node and UE that is not traveling with the mobile relay node. In other words, the information on the at least one UE provided to the wireless backhaul node or the network entity may include separate information on which UE is traveling with the mobile relay node and which UE is not traveling with the mobile relay node. 202407816 25

[0092] For example, the reporting by the mobile relay node (e.g., lAB-node) may comprise or consist of one or more of the following parameters: a number and / or identities of UEs attached to it that are flying / moving along with it, a number and / or identities of UEs attached to it that are not flying / moving along with it, mobility information for non-flying UEs attached to it including whether they are UAV UEs or not (the mobility information may include a velocity of the UE and / or a direction of movement of the UE). In other words, the information on the at least one UE may comprise at least one of a number of UEs connected or being attached to the mobile relay node (e.g., disambiguated between UE traveling with the mobile relay node and UE not traveling with the mobile relay node), an identifier of the at least one UE (e.g., disambiguated between UE traveling with the mobile relay node and UE not traveling with the mobile relay node, to ensure that the network is able to identify the respective UEs), a capability of the at least one UE (e.g., disambiguated between UE traveling with the mobile relay node and UE not traveling with the mobile relay node), a service used by the at least one UE (e.g., disambiguated between UE traveling with the mobile relay node and UE not traveling with the mobile relay node), a bearer used by the at least one UE (e.g., disambiguated between UE traveling with the mobile relay node and UE not traveling with the mobile relay node)), a data buffer status, or a load estimate that is based on current or history of data exchange.

[0093] The request by the wireless backhaul node (e.g., IAB donor) and report by the mobile relay node (e.g., lAB-node) may be transmitted in corresponding RRC messages. The information on the at least one UE (i.e., the information on the connected UEs) enables the network to manage radio resources (depending on the number of UEs in RRC_CONNECTED and the used services, or history of service usage, more or less bandwidth is required, e.g., considering the backhaul link capacity between the mobile relay node and wireless backhaul node), load (network is able to detect potential overload / resource shortage and may instruct the mobile relay node to reject or release UEs), and mobility (when the mobile relay node moves from a source wireless backhaul node to next wireless backhaul node, the target wireless backhaul node can be selected based on the number of connected UEs / used resources / level of mobility of relay nodes with respect to target nodes, which may depend on deployment density of wireless backhaul nodes) more efficiently. The information about the moving (e.g., flying) and non-moving UEs attached to the mobile relay node (e.g., flying IAB node) may then be 202407816 26 used by the wireless backhaul node (e.g., IAB donor) for triggering handovers pre-emptively and managing resource allocation / scheduling. Accordingly, the method for the wireless backhaul node (of Fig. 2) may comprise performing 250, at least one action related to connection reconfiguration, e.g., an action related to handover or reselection (e.g., of UEs not traveling with the mobile relay node) based on the information on the at least one UE. In effect, the network entity or wireless backhaul node may indicate a non-traveling UE (that is connected / attached via the mobile relay node node) where to go when connection drops. For example, the handover may be an enforced handover (if an active connection is established) or re-selection information of target relay node nearby (for idle mode UEs). Additionally, or alternatively, the method for the wireless backhaul node (of Fig. 2) may comprise configuring 255 the mobile relay node with respect to at least one of the radio resources to be used or Quality of Service, QoS, requirements based on the information on the at least one UE, e.g., considering the connected UEs and their service usage or service history. For example, based on the mobiled relay node’s (mlAB’s) characteristics (provided by the mlAB DU to the IAB donor), the network may authorize and / or configure the mobile relay node for managing radio resources and Quality of Service (QoS) for connected UEs.

[0094] In general, the proposed concept is used for mobile relay nodes. In the following, two mechanisms are covered to enable the wireless backhaul node / network entity to determine that the mobile relay node is mobile, i.e. , actively moving and in particular flying.

[0095] In the first mechanism, the mobile relay node (e.g., the MT of the IAB node) has UAV capabilities. In this mechanism, once the network receives a height report and a measurement report with multiple strong RSRP (Reference Signal Received Power) values from the mobile relay node (e.g., lAB-node MT), it triggers a request / configuration to provide information about the UE connected to the lAB-node. In other words, the method for the mobile relay node (of Fig. 1 b) may comprise providing 110 one or more reports to the wireless backhaul node and / or a network entity, with the reporting configuration or request being received in response to the one or more reports. For example, the one or more reports may comprise at least one of a height report, a timing advance report, a flight path report or a report on a received power of one or more downlink reference signals. On the network side, the act of determining 202407816 27

[0096] 220 that the relay node is a mobile relay node may comprise receiving 210 the one or more reports from the relay node. For the network, the one or more reports are indicative of the relay node being a mobile relay node. Accordingly, determining 220 that the relay node is a mobile relay node may be based on the one or more reports.

[0097] Fig. 3 shows a flowchart of operations for a mobile IAB node (mobile relay node, such as an air taxi), for the first mechanism. In this flow, the mobile relay node sends height and measurement reports. If an information request / configuration is received, the mobile relay node collects and sends UE information.

[0098] Fig. 4 shows a flowchart of operations for an IAB donor node (wireless backhaul node) for the first mechanism. In this flow, the wireless backhaul node waits until it receives height and measurement reports and / or flight mode indication from a mobile relay node. If it received such information, it sends a request / configuration for UE information. It then receives the UE information.

[0099] In the second mechanism, the mobile relay node (e.g., the MT part of the IAB node) does not have UAV capabilities. In this mechanism, once the network detects that the mobile relay node (e.g., IAB node) is moving / flying e.g., using FD-MIMO feedback, timing advance values, or other means, it requests the mobile relay node for information on the UEs connected to it that are flying / moving with it. In this mechanism, determining 220 that the relay node is a mobile relay node may comprise detecting 215 movement of the relay node based on changes in at least one of: beamforming information, fulldimension multiple input multiple output, FD-MIMO, feedback information, timing advance values, Doppler shift, time of arrival, time difference of arrival, or angle of arrival measurements associated with the relay node (based on uplink signals received from the mobile relay node).

[0100] Fig. 5 shows a flowchart of operations for a mobile IAB node (mobile relay node, such as an air taxi) for the second mechanism. In this case, the mobile relay node does not have to prepare specific reports (i.e., the reports for UAV UEs). Thus, the mobile relay node waits until an information request / configuration is received, and then collects and sends the UE information. Fig. 6 shows a flowchart of operations for an IAB donor node (wireless backhaul node) for the second mechanism. The flow starts with detecting a 202407816 28 flying / moving mobile relay node (e.g., IAB node) or a flight mode. If the detection is successful, the wireless backhaul node / network entity sends information for UE information, and receives the UE information.

[0101] The information about moving / non-moving (e.g., flying / non-flying) UEs connected to the mobile relay node e (e.g., mlAB) helps in improving service for all the UEs, especially during handovers or re-selection. The proposed concept provides mechanisms for both cases when the mobile relay node (e.g., IAB-MT) has UAV UE capabilities or not.

[0102] The proposed concept is related to mobile integrated access and backhaul, urban air mobility, and flying mode detection.

[0103] The aspects and features described in relation to a particular one of the previous examples may also be combined with one or more of the further examples to replace an identical or similar feature of that further example or to additionally introduce the features into the further example.

[0104] Examples may further be or relate to a (computer) program including a program code to execute one or more of the above methods when the program is executed on a computer, processor or other programmable hardware component. Thus, steps, operations or processes of different ones of the methods described above may also be executed by programmed computers, processors or other programmable hardware components. Examples may also cover program storage devices, such as digital data storage media, which are machine-, processor- or computer-readable and encode and / or contain machine-executable, processor-executable or computer-executable programs and instructions. Program storage devices may include or be digital storage devices, magnetic storage media such as magnetic disks and magnetic tapes, hard disk drives, or optically readable digital data storage media, for example. Other examples may also include computers, processors, control units, (field) programmable logic arrays ((F)PLAs), (field) programmable gate arrays ((F)PGAs), graphics processor units (GPU), application-specific integrated circuits (ASICs), integrated circuits (ICs) or system-on-a-chip (SoCs) systems programmed to execute the steps of the methods described above. 202407816 29

[0105] It is further understood that the disclosure of several steps, processes, operations or functions disclosed in the description or claims shall not be construed to imply that these operations are necessarily dependent on the order described, unless explicitly stated in the individual case or necessary for technical reasons. Therefore, the previous description does not limit the execution of several steps or functions to a certain order. Furthermore, in further examples, a single step, function, process or operation may include and / or be broken up into several sub-steps, -functions, -processes or - operations.

[0106] If some aspects have been described in relation to a device or system, these aspects should also be understood as a description of the corresponding method. For example, a block, device or functional aspect of the device or system may correspond to a feature, such as a method step, of the corresponding method. Accordingly, aspects described in relation to a method shall also be understood as a description of a corresponding block, a corresponding element, a property or a functional feature of a corresponding device or a corresponding system.

[0107] The following claims are hereby incorporated in the detailed description, wherein each claim may stand on its own as a separate example. It should also be noted that although in the claims a dependent claim refers to a particular combination with one or more other claims, other examples may also include a combination of the dependent claim with the subject matter of any other dependent or independent claim. Such combinations are hereby explicitly proposed, unless it is stated in the individual case that a particular combination is not intended. Furthermore, features of a claim should also be included for any other independent claim, even if that claim is not directly defined as dependent on that other independent claim. 202407816 30

[0108] Reference Numerals

[0109] 10: apparatus (for mobile relay node)

[0110] 12: one or more interfaces (wireless transceiver)

[0111] 14: one or more processing devices (processor)

[0112] 16: memory

[0113] 20: apparatus (for wireless backhaul node)

[0114] 22: one or more interfaces (wireless transceiver)

[0115] 24: one or more processing devices (processor)

[0116] 26: memory

[0117] 30: UE (User Equipment)

[0118] 100: mobile relay node (IAB node)

[0119] 110: providing one or more reports

[0120] 120: receiving a reporting configuration and / or a request for information on at least one user equipment

[0121] 130: determining which UE using or being attached to the mobile relay node is traveling with the mobile relay node

[0122] 140: providing the information on the at least one UE

[0123] 150: providing information on the mobile relay node being a mobile relay node that is moving to at least one UE

[0124] 200: wireless backhaul node (IAB donor node)

[0125] 210: receiving one or more reports from the relay node

[0126] 215: detecting movement of the relay node

[0127] 220: determining that the relay node is a mobile relay node

[0128] 230: configuring the mobile relay node to report the information on at least one UE or providing a request for the information on the at least one UE to the mobile relay node

[0129] 240: obtaining the information on the at least one UE

[0130] 250: performing at least one action related to handover or re-selection

[0131] 255: configuring the mobile relay node with respect to at least one of radio resources to be used or Quality of Service, QoS, requirements

Claims

202407816 1ClaimsWhat is claimed is:1 . A method for a mobile relay node in a cellular mobile communication system, the method comprising: receiving (120), from a wireless backhaul node and / or a network entity, a reporting configuration and / or a request for information on at least one user equipment, UE, using or being attached to the mobile relay node; and providing (140), to the wireless backhaul node and / or a network entity, the information on the at least one UE according to the reporting configuration and / or in response to the request.

2. The method according to claim 1 , wherein the method is performed by a moving and / or flying relay node.

3. The method according to one of the claims 1 to 2, wherein the method comprises providing (150) information on the mobile relay node being a mobile relay node that is moving to at least one UE.

4. The method according to one of the claims 1 to 3, wherein the method comprises providing (110) one or more reports to the wireless backhaul node and / or a network entity, wherein the reporting configuration or request is received in response to the one or more reports, wherein the one or more reports comprise at least one of a height report, a timing advance report, a flight path report or a report on a received power of one or more downlink reference signals.

5. The method according to one of the claims 1 to 4, wherein the method comprises determining (130) which UE using or being attached to the mobile relay node is traveling with the mobile relay node, wherein the information on the at least one UE provided to the wireless backhaul node or the network entity includes information on which UE is traveling with the mobile relay node, wherein the information on the at least one UE provided to the wireless backhaul node or the network entity includes separate information on which UE is traveling with the mobile relay node and which UE is not traveling with the mobile relay node.202407816 26. The method according to one of the claims 1 to 5, wherein the information on the at least one UE comprises at least one of a number of UE connected or being attached to the mobile relay node, an identifier of the at least one UE, a capability of the at least one UE, a service used by the at least one UE, a bearer used by the at least one UE, data buffer status, or a load estimate that is based on current or history of data exchange.

7. A method for a wireless backhaul node in a cellular mobile communication system, comprising: determining (220) that a relay node is a mobile relay node; configuring (230) the mobile relay node to report information on at least one user equipment, UE, and / or providing a request for information on at least one user equipment, UE, using or being attached to the mobile relay node to the mobile relay node; and obtaining (240) the information on the at least one UE according to the configured reporting and / or in response to the request.

8. The method according to claim 7, wherein the act of determining (220) that the relay node is a mobile relay node comprises receiving (210) one or more reports from the relay node, the one or more reports being indicative of the relay node being a mobile relay node.

9. The method according to claim 7, wherein the act of determining that the relay node is a mobile relay node comprises detecting (215) movement of the relay node based on changes in at least one of: beamforming information, full-dimension multiple input multiple output, FD-MIMO, feedback information, timing advance values, Doppler shift, time of arrival, time difference of arrival, or angle of arrival measurements associated with the relay node.

10. The method according to one of the claims 7 to 9, wherein the method comprises performing (250) at least one action related to handover or re-selection based on the information on the at least one UE, and / or wherein the method comprises configuring (255) the mobile relay node with respect to at least one of202407816 3 radio resources to be used or Quality of Service, QoS, requirements based on the information on the at least one UE.11 . A method for a wireless backhaul node in a cellular mobile communication system, comprising: obtaining (240) information on at least one user equipment, UE, using or being attached to a mobile relay node from a mobile relay node; and performing (250) at least one action related to handover or re-selection based on the information on the at least one UE.

12. The method according to one of the claims 1 to 11 , wherein the method according to one of the claims 1 to 6 is performed by an integrated access and backhaul node and / or at least one of the methods according to one of the claims 7 to 11 is performed by an integrated access and backhaul donor node.

13. A computer program having a program code for performing one of the methods of claims 1 to 11 , when the computer program is executed on a computer, a processor, or a programmable hardware component.

14. An apparatus for a mobile relay node in a cellular mobile communication system, the apparatus comprising: one or more interfaces configured to communicate in the cellular mobile communication system; and one or more processing devices configured to perform one of the methods of claims 1 to 6.

15. An apparatus for a wireless backhaul node in a cellular mobile communication system, the apparatus comprising one or more interfaces configured to communicate in the cellular mobile communication system; and one or more processing devices configured to perform at least one of the methods of one of the claims 7 to 11.

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