Managing network connectivity in a wireless communication system

Abstract

A method for use in managing connectivity of a wireless access backhaul, WAB, node, is disclosed. The WAB node includes a mobile termination, MT, component and a gNB component. The method at the WAB n

Description

The present invention generally relates to managing network connectivity in a wireless communication system. Particularly, the present invention relates to managing network connectivity in a wireless communication system including at least one Wireless Access Backhaul, WAB, node. In an example, the wireless communication system includes at least one mobile Wireless Access Backhaul, WAB, node. Background Wireless communication systems are largely deployed to address a wide range of applications, from mobile broadband, massive machine type communications to Ultra Reliable Low Latency Communications (URLLC). Such systems allow a plurality of user equipment (UE) or mobile terminals to share the wireless medium to exchange several types of data content (e.g., video, voice, messaging ...) over a radio access network (RAN) through one or more base stations. The base stations are conventionally wired-connected (e.g., through fiber) to a core network, forming an intermediate network, named backhaul (BH). Examples of such wireless multiple-access communication systems include systems based on 3rd generation partnership project (3GPP - RTM) standards, such as fourth-generation (4G) Long Term Evolution (LTE) or recent fifth-generation (5G) New Radio (NR) systems, or systems-based IEEE 802.11 standards, such as WiFi. The demand for network densification increases due to the rising number of users and higher throughput requirement. Facing the issues of high deployment costs and time of the wired backhaul networks with network densification, 3GPP has proposed, in recent release 16 for 5G NR, a wireless backhaul, also known as Integrated Access and Backhaul, IAB, where part of the wireless (i.e., radio) spectrum is used for the backhaul connection of base stations instead of fiber. The wireless backhaul communications (between base stations) may use the same radio resources as access communications (between a base station and UEs). IAB turns out to be a competitive alternative to the fiber-based backhauling in dense areas or areas difficult to cover, as it allows scalable and rapid installations without the burden of cabling the base stations. IAB is most likely to operate in the millimeter wave (mmWave) band to achieve the required Gbps (gigabits per second) data rate. Urban environments are usually characterized by a high density of users along with the presence of a significant number of vehicles (e.g., public / private passenger transportation, goods delivery, food trucks...). The speed of some of the vehicles may be pretty low or at least similar to pedestrian speed and some of these vehicles may even be temporarily stationary. Some of these vehicles (e.g., buses, trains or trams), may have predictable routes and / or limited mobility areas (e.g., some vehicles, such as food trucks or promotional vehicles, may be located outside stadiums or show venues) while others may have predictable stationary locations (e.g., taxis). 3GPP is considering that such vehicles could offer an opportunity to increase network coverage and connectivity to the UEs inside the vehicles, or even to UEs in proximity to the vehicles, by installing on these vehicles on-board base stations (or base station elements) that would act as relays. These relays would rely on 5G wireless backhaul (typically IAB, or Integrated Access &Backhaul) for connecting to a fixed donor device. Thus, based upon the fixed IAB foundations set out in Releases 16 and 17, 3GPP is now considering Mobile IAB systems and architecture, as a part of the Release 18 framework, in order to address scenarios focusing on mobile lAB-nodes mounted on vehicles (for example, a bus, a train, a taxi). In such scenarios, mobile lAB-nodes can also be referred to as Vehicle Mounted Relays (VMR), providing 5G coverage / capacity to on-board and / or surrounding UEs. The technical benefits of using vehicle relays include, among others, the ability of the relay vehicle to get better coverage than the nearby UE, thanks to better RF / antenna capabilities, thus providing the UE with a better link to the macro network. Additionally, a vehicle relay is expected to have less stringent power / battery constraints than the UEs. Some enhancements of the existing wireless access backhauling, WAB, systems and architecture are further considered by 3GPP for Release 19. Such enhancements consider the need for 5G access for UEs onboard aircrafts, cruise ships, helicopters and vehicles in remote areas with limited sky visibility (e.g., where terrestrial cellular coverage or Wi-Fi coverage is not available), support for onboard / on-site mobile edge computing (MEC), local services, and direct local inter-UE communications or local Next Generation Node B (gNB) deployment in public safety or disaster recovery scenarios. The backhauling links for the base stations providing the 5G access in such scenarios would then be operated over either a terrestrial network (TN), or a non-terrestrial network (NTN), with a possibility to handover communications from a terrestrial network to a non-terrestrial network and vice-versa. Such base stations can be referred to as Wireless Access Backhaul (WAB) nodes, or mobile WAB (MWAB) nodes. As part of these wireless backhauling enhancements, 3GPP is also considering some evolution to the former LTE-based Femto framework, including a new 5G Femto or 5G Femtocell that would offer 5G indoor coverage improvement while allowing high bandwidth and throughput at home for new immersive applications such as AR / VR / MR gaming, e-sports, UHD 8K video, telepresence, etc. A WAB node is made of a Mobile Termination, WAB-MT, part used for connecting to some fixed existing infrastructure and used to provide backhauling connectivity as previously discussed. The WAB node also embeds a base station or gNB, WAB-gNB, (also referred to as a gNB part) to serve UEs. WAB nodes may be referred to as mobile Wireless Access Backhaul (MWAB) nodes. This disclosure relates to WAB nodes and MWAB nodes and thus, references to MWAB nodes should be taken to refer to WAB nodes and vice versa. 3GPP TS 38.423 defines the Xn interface, which is a logical interface between two NG-RAN network nodes, or base stations, providing means for interconnecting these two NG-RAN nodes. For instance, the Xn interface provides means for managing resource multiplexing between NG-RAN network nodes, or base stations, allowing NG-RAN network nodes (i.e., base stations, or gNBs) in proximity to coordinate their radio resources utilization so as to prevent the NG-RAN network nodes to mutually interfere. A need for resource multiplexing management also applies when considering a WAB-gNB and the NG-RAN network node serving the WAB-MT of the WAB node the WAB-gNB belongs to, as the WAB-gNB and the serving NG-RAN network node are likely to be close enough to interfere. Thus, having an Xn connection between the WAB-gNB of a WAB node and the NG-RAN network node serving the WAB-MT of the WAB node is desirable as it would at least facilitate managing resource multiplexing to avoid or minimize interference between the WAB-gNB and the serving NG-RAN network node. Xn connection may also allow for faster UE handover process between a WAB-gNB and a surrounding NG-RAN network node (including the NG-RAN network node serving the WAB-MT collocated with the WAB-gNB), compared to an NG-level handover process, which is performed through the 5G core network, as defined in 3GPP TS 23.502 with N2 based handover. Having faster handover may be particularly interesting when performed between two WAB-gNBs which respective WAB nodes are bound to a same vehicle, i.e., a train or cruise ship, in order to ensure service continuity at UE level. In this latter case, having a Xn connection would not only account for faster handover but would also allow for faster load balancing coordination between the several bound WAB nodes. Summary In accordance with an aspect of the present invention, there is provided a method for use in managing connectivity of a wireless access backhaul, WAB, node, the WAB node including a mobile termination, MT, component and a gNB component, the method at the WAB node including: performing connection setup to establish a Xn connection between the gNB component of the WAB node and a RAN node based on information shared between the WAB node and the RAN node. In accordance with another aspect of the present invention, there is provided a method for use in managing connectivity of a wireless access backhaul, WAB, node, the WAB node including a mobile termination, MT, component and a gNB component, the method including: performing, at a RAN node, connection setup to establish a Xn connection between the gNB component of the WAB node and the RAN node based on information shared between the WAB node and the RAN node. In accordance with another aspect of the present invention, there is provided a method for use in managing connectivity of a WAB node as recited in claim 70 of the accompanying claims. In accordance with another aspect of the present invention, there is provided an apparatus for a WAB node as recited in claim 77 of the accompanying claims. In accordance with another aspect of the present invention, there is provided an apparatus for a RAN node as recited in claim 78 of the accompanying claims. The disclosed methods provide mechanisms for sharing information required for a Xn connection to be established between a gNB component of a WAB node and a RAN node (which may be a gNB component of another WAB node or a RAN node serving the MT component of the WAB node or a neighbouring RAN node. The information shared (whether the gNB component sends a request to establish a Xn connection or whether the RAN node sends a request to establish a Xn connection) may include information (e.g. one or more of: information for identifying the gNB component to the RAN node, information for identifying the MT component to the RAN node and information for identifying the RAN node to the gNB component) for enabling the RAN node to determine a gNB component of a WAB node, to which a Xn connection is to be established, is collocated with a MT component already served by the RAN node such that a Xn connection can be easily setup. Information may be shared between the gNB component or the RAN node and / or information may be shared between the MT component and the RAN node. In addition, information may be shared between the MT component and the gNB component. In particular, by sharing, by the MT component to the gNB component collocated with the MT component (e.g. both components are part of the same WAB node), information for identifying the RAN node serving the MT component, the gNB component can identify the RAN node serving its collocated MT component and send the request to establish a Xn connection to the serving RAN node such that a Xn connection can be easily setup. Thus, the describe mechansisms / methods enable a gNB component of a WAB node (WAB-gNB) to know which NG-RAN network node is serving its collocated WAB-MT and enable an NG-RAN network node to know which MT component of a WAB node (WAB-MT) is associated to a given WAB-gNB. The described mechanisms / methods may use existing messages, such as the Xn setup request / response messages, which messages include additional information / information elements and thus, the described mechanisms / methods do not require new or complicated signalling and the Xn connection can be set up efficiently with minimum delay. Once a Xn connection is setup, UE handover can be performed faster, and resource multiplexing can be performed easily between the RAN node 501 and gNB component 532 to avoid or minimise interference between the two RAN nodes (as the two RAN nodes are in close proximity). In the case where the RAN node is another WAB node, the information shared (between the two gNB components of the WAB nodes) includes information indicating one of the WAB node or the other WAB node is part of or belongs to or is bound to a group or set of WAB nodes (e.g. a set of bound nodes), for instance when the WAB nodes are located in the same geographical area. When receiving such information from the WAB node (e.g. a first WAB node), the other WAB node (e.g. a second WAB node) may then understand that first and second WAB nodes are part of the same WAB group. Then, handover of a UE served by a first WAB node may be “blindly” directed toward the second WAB node, i.e. without the need of measurement reports from the UE. This would enable fast UE handover and it would reduce the power consumption at the UE and at the WAB node. Further example features of the invention are described in other independent and dependent claims. Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus / device / unit aspects, and vice versa. Furthermore, features implemented in hardware may be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly. For example, in accordance with other aspects of the invention, there are provided a computer program comprising instructions which, when the program is executed by one or more processing units, cause the one or more processing units to carry out the method of any aspect or example described above or below and a computer readable storage medium carrying the computer program. Brief Description of the Drawings Different aspects of the invention will now be described, by way of example only, and with reference to the following drawings in which: Figure 1 is a schematic diagram illustrating an example wireless communication system in which the present invention may be implemented according to one or more embodiments; Figure 2 is a block schematic diagram illustrating an example wireless communication system (or Wireless Access Backhaul system) in which the present invention may be implemented according to one or more embodiments; Figure 3 is a block schematic diagram illustrating an example wireless communication system (or Wireless Access Backhaul system) in which the present invention may be implemented according to one or more embodiments; Figure 4 shows a block schematic representation of an example network node in accordance with one or more embodiments of the present invention; Figure 5 is a block schematic diagram illustrating an example arrangement of a wireless communication system (or Wireless Access Backhaul system) in which the present invention may be implemented according to one or more embodiments; Figure 6 and Figure 7 are schematic and simplified diagrams illustrating example message flows for use in managing network connectivity in a wireless communication system including at least one Wireless Access Backhaul, WAB, node in accordance with one or more embodiments of the present invention and which may be used for managing Xn connection establishment between a WAB-gNB and an NG-RAN network node; Figure 8 is a schematic and simplified diagram illustrating an example message flow for use in managing network connectivity in a wireless communication system including at least one Wireless Access Backhaul, WAB, node in accordance with one or more embodiments of the present invention and which may be used for managing Xn connection establishment between two WAB-gNBs; Figure 9 is a flowchart of an example method for managing Xn connection establishment between a WAB-gNB and an NG-RAN network node according to one or more embodiments of the present invention; Figure 10 is a flowchart of an example method for managing Xn connection establishment between a WAB-gNB and an NG-RAN network node according to one or more embodiments of the present invention; Figure 11 is a flowchart of an example method for managing Xn connection establishment between two WAB-gNBs according to one or more embodiments of the present invention; Figure 12 is a flowchart of a method, performed at a WAB node, for use in managing connectivity of a WAB node to establish a Xn connection between the gNB component of the WAB node and a RAN node; and Figure 13 is a flowchart of a method, performed at a RAN node, for use in managing connectivity of a WAB node to establish a Xn connection between the gNB component of the WAB node and a RAN node. Detailed Description Figure 1 illustrates an example communication system 100 in which the present invention may be implemented according to one or more embodiments. As depicted, the example system 100 is a wireless communication system, in particular a mobile radio communication system such as a fifth-generation (5G) New Radio (NR) system including a Wireless Access Backhaul (WAB) communication system or network. Although in the following description, embodiments and examples of embodiments of the present invention will be described with respect to a 5G NR system, it will be appreciated that it is not intended that the present invention is necessarily limited to 5G NR systems and may be used in any wireless communication systems having wireless backhaul links. The system 100 comprises a plurality ofUEs (User Equipment) 111, 112, 113, 121, 122, 123, 131, 132, 133, 134, 141, 142, 143, 151, 152, 153 and 154, a communication satellite 160, a satellite dish 101, a remote core network 170, three fixed Base Stations 102, 103 and 104, a plurality of Wireless Access Backhaul (WAB) nodes, also referred to as mobile wireless access backhaul (MW AB) devices: such as MW AB node 110 (mounted on plane 161), MW AB nodes 120a and 120b (mounted on train 162), WAB node 130 (or Home gNB, mounted on a house 163), MW AB node 140 (mounted on a Unmanned Aerial Vehicle (UAV) 164) and MW AB node 150 (mounted on a backpack 165 or other carrier that can be carried by a user (e.g., in a disaster zone)). In more general terms, the MW AB node may be mounted on or in a vehicle (such as a train, bus, taxi, tram, etc.) and / or an aircraft or flying vehicle (such as a plane, UAV, helicopter, etc. ) and / or a building (such as a house, enterprise / company / office building, hotel building, airport building, sports / event buildings, shopping center building, etc..) and / or a portable carrier that can be carried by a user, for example, in a disaster zone or for public safety (such as a backpack, bag, etc), and / or public infrastructure elements or units (such as lamp posts, traffic lights, etc). In an example where the MW AB node is implemented in a 5G femto network, the MW AB node functions as a 5G femto node and may be mounted at a building (such as a house, enterprise / company / office building, hotel building, airport building, sports / event buildings, shopping center building, etc..) and / or public infrastructure elements or units (such as lamp posts, traffic lights, etc.). In some cases, particularly but not exclusively when a MW AB node 130 is mounted to a fixed structure, e.g., when the MW AB node is functioning as a 5G femto node, the MW AB node 130 may be considered a WAB node, which also may be referred to as a Home gNB, and is based on the same architecture as the MW AB node, i.e. the Home gNB comprising the Mobile Termination and gNB required to be a Wireless Access Backhaul node. Some examples of UEs include smartphones / tablets (such as UEs 111, 123, 134, 142, 152), extended Reality (XR) headsets (such as UEs 112, 122, 132), cameras (such as UEs 131, 141 and 151), fixed video cameras (such as UEs 113, 121, 133, 153) or mobile / wearable video cameras (such as UEs 143 and 154). In general, the UE may be any portable or handheld or mobile telephone, a smartphone, a tablet, a portable or fixed computer, fixed or mobile camera, portable television, other smart devices or other similar wireless communication device. In the following description, the term UE will be used and it is not intended to limit the description to any particular type of wireless communication device. Base stations 102, 103 and 104 are interconnected through a wired link infrastructure 180, preferably based on optical fiber or any other wired means. Base stations 102, 103 and 104 are also connected to the core network 170 through a wired link infrastructure 190, preferably based on optical fiber or any other wired means. In some implementations, base stations 102, 103 and 104 are 5G NR base stations (referred to as a gNB), as defined in 3GPP TS 38.300 V18.0.0 specification document. Satellite dish 101 (e.g., satellite gateway) is also connected to wired link infrastructure 180 or 190, or to both infrastructures 180, 190. That is to say, the satellite dish 110 is connected to one or more of the wired link infrastructures 180, 190. While infrastructure 180 and 190 are referred to as separate, it should be understood that it may be the same infrastructure. In order to extend the network coverage of base stations 102, 103 and 104 and reach the remoteUEs 111, 112, 113, 121, 122, 123, 131, 132, 133, 134, 141, 142, 143, 151, 152, 153 and 154, MW AB nodes, or MWAB-nodes, 110, 120a, 120b, 130, 140 and 150, have been installed on vehicles / mobile equipment / building 161,162, 163, 164 and 165. By acting as relaying nodes between the base stations 102, 103 and 104 and the UEs 111, 112, 113, 121, 122, 123, 131, 132, 133, 134, 141, 142, 143, 151, 152, 153 and 154, MWAB-nodes 110, 120a, 120b, 130, 140 and 150 allow overcoming the reachability issue resulting from limited sky visibility while ensuring support for onboard / on-site mobile edge computing (MEC), local services, and direct local inter-UE communications. This allows further communication between base stations 102, 103 and 104 and the UEs 111, 112, 113, 121, 122, 123, 131, 132, 133, 134, 141, 142, 143, 151, 152, 153 and 154 and / or communications between the UEs served by a same MWAB-node (e.g., UEs 151, 152, 153 and 154 connected toMWAB node 150). The base stations 102, 103 and 104, the MWAB nodes 110, 120a, 120b, 130, 140 and 150, the satellite 160, the satellite dish 101 are thus forming a backhaul network or WAB network (also referred to as WAB topology), or MWAB network (also referred to as MWAB topology), which accommodates UEs 111, 112, 113, 121, 122, 123, 131, 132, 133, 134, 141, 142, 143, 151, 152, 153 and 154. The terms WAB network, MWAB network, WAB topology and MWAB topology will be used interchangeably in the following. The WAB network forms the Radio Access Network (RAN) or as referred to with respect to 5G, Next Generation (NG) RAN. The WAB network forms the Radio Access Network (RAN) or as referred to with respect to 5G, the Next Generation (NG) RAN. The base stations 102, 103 and 104, the MWAB nodes 110, 120a, 120b, 130, 140 and 150, the satellite 160, the satellite dish 101, and the core network 170 are thus forming a WAB system, or MWAB system, which accommodates UEs 111, 112, 113, 121, 122, 123, 131, 132, 133, 134, 141, 142, 143, 151, 152, 153 and 154. The terms WAB system and MWAB system will be used interchangeably in the following. A base station, or gNB, such as base station 102, 103 or 104, is a logical node that provides the NR-connectivity, hosting both higher layer protocols, such as PDCP (Packet Data Convergence Protocol) and RRC (Radio Resource Control) protocols, and lower layer protocols, such as the RLC (Radio Link Control), MAC (Medium Access Control) and physical layer protocols. The MW AB nodes 110, 120a, 120b, 130, 140 and 150, which may serve multiple radio sectors, are wireless backhauled to the base station 102, 103 or 104, via a single logical hop associated to a single radio link (i.e., radio links DI041 a, DI04lb, D1031, D1022, DI021), or split into two radio links in the case of satellite relaying (radio links D1601a and D1601b). Although a single logical hop is shown in figure 1, it will be appreciated that the MW AB nodes could be wireless backhauled to the base station over multiple logical hops (for example, similar to the multiple hops provided in an IAB network). Each MW AB node consists of a gNB or RAN node or base station component or unit or part which is referred to as a MWAB / WAB gNB or MWAB / WAB-gNB, or also referred to as a MW AB base station, and a Mobile Termination (MT) component or unit or part which is referred to as an MWAB / WAB-MT, MWAB / WAB MT or MWAB / WAB-Mobile Termination. The MWAB-gNB functionality on an MWAB-node allows or enables the connection to a UE. The MWAB-MT functionality includes, e.g., physical layer, layer-2, RRC and Non-Access Stratum (NAS) functionalities and allows or enables connection to a base station, or gNB, such as base station 102, 103 or 104. MW AB nodes 110, 120a, 120b, 140 and 150 are intended to be mobile devices that will move along with the vehicle they are mounted on. However, these MW AB nodes may remain at a fixed location for a significant duration when their associated vehicle is remaining still (e.g., a train may stop at a railway station, a plane may be parked at an airport for a while, a car / truck / fire engine, or similar appropriate vehicle may be parked, for example nearby a disaster area). MW AB node 130 is likely to remain at fixed location and may be a 5G Femto node, which provides NR access at home or at enterprise premises. In such case, the 5G Femto node 130 may have a direct connection DI700 to the Core Network 170 through the wired link infrastructure 190, which is preferably based on optical fiber or any other wired means. Figure 2 is a simplified schematic diagram of a 5G system 200 in which the present invention may be implemented according to one or more embodiments. This figure illustrates the possible standardized interfaces between the various elements composing the system. First, it represents a User Equipment (UE) 201 having a Uu interface with the New Generation (NG) Radio Access Network (RAN or NG-RAN) 202, and a N1 interface with an Access and Mobility management Function (AMF) entity or AMF 212 in a 5G core network (5GC) 210. Each base station composing the RAN 202 has a N2 interface with one or more Access and Mobility management Function (AMF) entity or AMF, like AMF 212, and a N3 interface with one or more User Plane Function (UPF) entity or UPF, like UPF 211. The N1 interface is used to convey Non-Access Stratum (NAS) protocol messages between a UE 201 and an AMF 212. NAS messages are used for the signaling between the UE and the core network for various procedures such as registration, session establishment, security, and mobility management. Actually, NAS messages are conveyed through the Uu interface between the UE 201 and the RAN 202, and the N2 interface between the RAN 202 and the AMF 212. An AMF 212 is responsible for handling registration, authentication, connection and mobility management tasks for a UE. There may be several AMFs in a 5G core network, a standardized interface N14 enables the communications between AMFs. When a UE registers to the network through a serving base station, the serving base station will connect to an AMF suitable to handle the UE. When the UE 201 is registered, one or more Protocol Data Unit (PDU) session(s) can be set up to transfer data flows between the UE 201 and the Data Network (DN) 220 providing internet access. A PDU session is established between a UE 201 and a User Plane Function (UPF) 211 in the 5G core network 210. In the user plane, the UPF 211 connects to the Data Network (DN) 220 through the interface N6, and it is responsible for data packets routing with the required Quality of Service (QoS). There may be several UPFs on the data path with a N9 interface between UPFs. The user data between a UE 201 and the Data Network 220 are thus conveyed through interfaces Uu, N3, N6 and potentially N9. In the control plane, the setup of PDU sessions is handled through NAS messages involving the Session Management Function (SMF) entity or SMF 213 in the 5G core network 210. The NAS messages are still exchanged between the UE 201 and the AMF 212 through the N1 interface, but an additional interface Nil between an AMF 212 and the SMF 213 is used to reach the SMF 213. In a 5G core network, the SMF is responsible for the setup, modification, and release of PDU sessions for a UE, as well as the Internet Protocol (IP) address allocation for the UE. To manage a PDU session, the SMF 213 controls the UPF 211 (configuration) based on QoS policy defined for the PDU session. For this purpose, a N4 interface exists between the SMF 213 and the UPF 211. A base station in RAN 202 operating in a first Public Land Mobile Network (PLMN) may serve a UE having a subscription for a second PLMN (called home PLMN) different from the first PLMN (called visited PLMN). In such a roaming case, there are two options to provide the UE 201 with an access to the Data Network 220. In a first option called home routed, the UPF and its controlling SMF to access the Data Network 220 are located in the 5G core network for the home PLMN. However, the SMF of the visited PLMN controls the intermediate UPF(s) of the visited PLMN, and interacts with the SMF of the home PLMN. In a second option called local breakout, the UPF and its controlling SMF to access the Data Network 220 are located in the 5G core network for the visited PLMN. However, the SMF interacts with the home 5G core network to get QoS policies associated with the UE’s PDU session(s). Figure 3 is a simplified schematic diagram of a 5G system 300 involving a Wireless Access Backhaul (WAB) node (or a MW AB node), and in which the present invention may be implemented according to one or more example embodiments. This figure first represents a User Equipment (UE) 301 served by a WAB node 310 through the Uu interface. The WAB node 310 is composed of or includes a MT or WAB-MT or MWAB-MT unit / component / entity 311 (also called WAB-UE), and a gNB or RAN node or WAB-gNB, or MWAB-gNB unit / component / entity 312. Through the WAB-gNB 312, a WAB node acts as a gNB for UEs providing access to the 5G network, i.e. providing a NR access link to the UEs that can be located inside or outside the entity, such as a vehicle, equipped with the WAB node 310 (e.g. on entering / leaving the vehicle). In other words, the WAB-gNB 312 includes full base station or gNB function (including both Central Unit (CU) and distributed unit (DU)) and MT function, where the gNB function is used to communicate with UEs for access service and the MT function is used to communicate with another gNB for backhauling purpose. The WAB node 310 wirelessly connects to the 5G Core Network (using NR Uu interface) through an IP connectivity provided by PDU session(s) established by the WAB-MT 311 via a gNB 320, which can be called a backhaul RAN node or BH RAN node, backhaul base station, backhaul gNB or BH gNB. Acting as a legacy UE, the WAB-MT 311 connects via a NG-RAN cell of the BH gNB 320, through a backhaul link that may be a direct link or via a satellite (e.g. when the WAB node 310 is embedded in an airplane). Thus, a PDU session is provided either by a Terrestrial Network (TN) or by a Non-Terrestrial Network (NTN). In addition, the WAB node 310 may embed some core network functions, like a UPF 313, to enable local services to the served UEs. The traffic associated to these local services does not need to use the links to / from the core network via the BH gNB 320, which has the advantages to reduce the load on these links and to run applications having very low latency requirements. For example, where the WAB node 310 includes a UPF 313, the WAB node can connect to one or more local servers (e.g. mounted at the same entity as the WAB 310) enabling a UE served by the WAB access to local services provided by the local servers with no traffic required outside of the WAB node / server environment. The BH gNB 320 provides N3 and N2 interfaces so that the WAB-MT 311 can access to the functions of its 5G core network 330. Indeed, a WAB-MT 311 may have access to some or several PLMNs through the appropriate subscriptions, and it may connect in a non-roaming manner to one PLMN, e.g. PLMN1 supported by the BH gNB 320, and may then have access to the corresponding 5G core network 330. In particular the WAB-MT 311 interacts with the AMF 332, which can be called the WAB AMF, and establishes PDU session(s) with the UPF 331, which can be called the WAB UPF. The WAB UPF 331 is controlled by the SMF 333 (through N4 interface), which can be called the WAB SMF, and which also interacts with the WAB AMF 332 (through Nil interface). There may be one or several intermediate UPFs between the BH gNB 320 and the WAB UPF 331 as mentioned in the Figure 2. An interface internal to the WAB node 310 exists between the WAB-gNB 312 and the WAB-MT 311, which may be implemented on different or the same hardware resources. For instance, these two functions are implemented on the same processing unit 402 of Figure 4, and interactions exist between the two functions. Once the WAB-MT 311 has established a PDU session with the WAB UPF 331, the WAB node is ready to serve UEs and the WAB-gNB 312 can start operating as a legacy gNB. The WAB-gNB may support various PLMNs and the UE 301 connects to one PLMN, e.g. PLMN2, which may be different from the PLMN1 the WAB-MT 311 connects to. In the case where PLMN1 and PLMN2 are different, the UE 301 connects to the 5G core network 340, including a UPF 341, which can be called the UE UPF, an AMF 342, which can be called the UE AMF, and a SMF 343, which can be called the UE SMF. The UE SMF 343 interacts with the UE AMF 342 (through Nil interface) and the UE UPF 341 (through N4 interface). In the case where the PLMN1 and the PLMN2 are the same, the UE UPF 341, the UE AMF 342, the UE SMF 343, the WAB UPF 331, the WAB AMF 332, and the WAB SMF 333 belong to the same 5G core network 350. In addition, the UE UPF 341 and the WAB UPF 331 may be the same UPF, the UE AMF 342 and the WAB AMF 332 may be the same AMF, the UE SMF 343 and the WAB SMF 333 may be the same SMF. The connections between the UE 301 to the UE UPF 341 and to the UE AMF 342 are possible thanks to the N6 interface between the UE UPF 341 and the WAB UPF 331, and thanks to the N6 interface between the WAB UPF 331 and the UE AMF 342. These N6 interfaces enable the establishment of N2 interface between the WAB-gNB 312 and the UE AMF 342, and the establishment of N3 interface between the WAB-gNB 312 and the UE UPF 341, which allows the UE 301 to access the Data Network 360. In case the WAB-MT 311 connects to the 5G network in a roaming manner corresponding to the home routed option, then the PLMN1 is the visited PLMN and the WAB UPF 331 connects to another UPF not represented in the Figure 3 in the home PLMN through a N9 interface. It is this other UPF that provides the connection to the UE UPF 341 and the UE AMF 342 through N6 interfaces. In case the WAB-MT 311 connects to the 5G network in a roaming manner corresponding to the local breakout option, then the PLMN1 is the visited PLMN and the WAB UPF 331 directly connects to the UE UPF 341 and the UE AMF 342 through N6 interfaces as shown in the Figure 3. Finally, the WAB-gNB 312 may use the backhaul link between the WAB-MT 311 and the BH-gNB 320 and a PDU session established by the WAB-MT 311 to setup a Xn connection with another RAN node. In another embodiment, the WAB-gNB 312 may use a dedicated network interface to directly connect to another RAN node (e.g. the network interface 432 of figure 4). For instance, a Xn connection may be established between the WAB-gNB 312 and the BH-gNB 320. Figure 4 is a block schematic diagram of an example RAN node or network node or base station 400, such as base stations or gNBs or MW AB nodes shown in Figure 1 or WAB nodes, in accordance with one or more embodiments of the invention. Each of a MW AB node 110, 120a, 120b, 130, 140, or 150 of figure 1 may comprise the elements of the base station of figure 4. In the following description, the network node 400 will be referred to generally as a base station. As will be apparent to a skilled person, Figure 4 is a simplified schematic diagram and shows only some of the functional components of an example base station 400 for use in describing the one or more embodiments of the invention. The base station 400 includes components for transmitting and receiving communications. As shown in Figure 4, the base station 400 includes a processing unit 402, a wireless interface 404, one or more antennas 410, a network interface 432, and memory 418. The network interface 432 manages communications of the base station 400 with the core network, other base stations, local network functions (like UPF), or local servers. It may provide a standardized interface, wired (e.g., fiber) or wireless, to support these communications. Through this network interface 432, the base station 400 may implement the standardized interfaces N2 (based on NGAP protocol) and N3 (based on GPRS tunneling protocol) with the core network, and the standardized interface Xn (based on XnAP protocol) with other base stations of the Radio Access Network (RAN), all defined by the 3 GPP standard. The network interface 432 may not be present or active in case the base station 400 is a MW AB node that does not support local services, that is not used as a legacy base station like base station 102, 104 in Figure 1, and / or that is not used as a home base station providing Femto cells like base station 130 in Figure 1. The wireless interface 404 is configured to provide wireless communication via communication links (414) with other wireless devices, such as one or more UEs, e.g., link D1041b between base station 104 and the MT / UE unit of MW AB node 120b, or link D1202 between the gNB unit of MW AB node 120b and the UE 122. In case of MW AB node, the wireless interface 410 may then be used both for the wireless backhaul link(s) with backhaul base station(s) and for the wireless link(s) with the UE(s) served by the MW AB node. The wireless interface 404 may be compliant with a fifth-generation (5G) New Radio (NR) system and thus implementing the Uu interface defined by 3GPP standard, or with other wireless communication system. The wireless interface 404 is coupled to the processing unit 402 and typically includes one or more antennas (such as the antenna 410), a receiving unit 406 and a transmitting unit 408. The configuration of the wireless interface 404 may be limited to connect to one antenna, but preferably several antennas are used, in order to provide beamforming capability. Although not shown in Figure 4, the receiving unit 406 typically includes elements such as a receiver, demodulator, decoder, and the transmitting unit 408 typically includes elements such as a transmitter, modulator, coder. The receiving unit 406 and transmitting unit 408 may together be referred to as a transceiver. The processing unit 402 is configured to carrying out processing for operation of the base station 400. The processing unit 402 may be a single processor (e.g., Central Processing Unit) or may comprise two or more processors. The number of processors and the allocation of processing functions to the processors is a matter of design choice for a skilled person. The base station 400 includes memory 418 for storing data and computer programs containing instructions for the operation of the base station 400. Memory 418 includes RAM (Random Access Memory), ROM (Read Only Memory), or combination of both or as a non-limiting example a mass storage device such as a disk or a Solid-State Drive. Memory 418 includes a program memory in which are stored programs containing processor instructions for operation of the base station 400 and for implementing the methods in accordance with one or more embodiments of the invention. The programs may contain a number of different program elements or sub-routines containing processor instructions for a variety of different tasks, for example, for: establishing, controlling and releasing communications with the UEs (e.g., implementing the Uu interface); processing data and signalling received at the receiving unit 406; processing signalling (e.g., paging messages, System Information Blocks) and data for transmission by the transmitting unit 408. Memory 418 may further include memory (e.g., RAM) for storing information. For example, information stored in memory 418 may further include information associated with the mobile WAB node, such as information elements 420 related to a MW AB node, including MW AB information. The information elements may be static information elements and / or dynamic information elements. The information elements 420 may be associated to the base station 400 (when the base station is a MW AB node), and may be communicated to any network node or entity when necessary. The information elements may also be related to a MW AB node (which is not the base station 400), and stored after reception from the MW AB node or from another network node or entity. Other nodes or entities described, such as the gNB, AMF and UPF, may comprise information elements stored in their own respective memories. These information elements being related to a MW AB node (including WAB-MT connection information, WAB connection information, WAB neighbouring information, neighbour WAB cells list information, femto capability information, WAB co-location information, WAB group information, etc. as discussed below) or their capability to serve a MW AB node. Specific program elements / sub-routines stored in program memory may include one or more of the following: elements for performing connection setup to establish a Xn connection between the gNB component of a WAB node and a RAN node (e.g. neighbour RAN node) based on information shared between the WAB node and the RAN node. The information shared may include information for identifying a relationship between the WAB node and the RAN node: such a relationship may be a connection has been established between the MT component of the WAB node and the RAN node or in the case where the RAN node is another WAB node, the WAB node and the other WAB node belong or are part of the same group of WAB nodes. The elements may include one or more of: an element for sending a request to initiate establishment of a Xn connection between the gNB component of the WAB node and the RAN node; an element for receiving a response to the request; and / or an element for receiving a request to initiate establishment of a Xn connection between the gNB component of the WAB node and the RAN node; an element for sending a response to the request. Other elements that may be included will be apparent from the description of the example message flows and example methods set out below. In an example arrangement, a communication bus 424 provides communication and interoperability between the various elements included in the base station 400 or connected to it. The representation of the bus is not limiting and in particular, the processing unit 402 is operable to communicate instructions to any element of the base station 400 directly or by means of another element of the base station 400. In an example implementation, the base station 400 may be or may include an apparatus comprising one or more processing units or processors for performing or implementing the methods in accordance with one or more embodiments of the invention. In other words, the apparatus may be capable of performing one or more functions of the base station including performing the methods in accordance with one or more embodiments of the invention by means of the one or more processing units. For example, the one or more processing units use software to implement the one or more embodiments of the invention as described above with reference to the processing unit 402 of Figure 4. Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, a CPU of a microcontroller Unit (MCU), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated (e.g., on an Integrated Circuit) or discrete logic circuitry. However, alternatively, the one or more processing units for performing or implementing the methods may be implemented in hardware: for example, in the form of an Application Specific Integrated Circuit or ASIC or other hardware comprising logic element (s). Accordingly, the term “processing unit” as used herein may refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. Figure 5 illustrates an example of a wireless communication system 500, including a WAB network or WAB network system, according to some embodiments. The WAB network or WAB network system may be considered a mobile WAB network or a mobile WAB network system. A WAB network will also be referred to as a WAB network system, WAB topology, WAB system, topology or system and so in this application, the terms WAB network system, WAB network, WAB topology, WAB system, topology or system will be used interchangeably. The WAB network system of Figure 5, is composed of or comprises three base stations 501, 502 and 503, also referred to as Backhaul base stations, or backhaul gNBs (also referred to as BH-gNB) or backhaul RAN node (also referred to as BH RAN node), two core networks 510 and 520, with the respective AMF entities 51 la and 511b (for Core Network 510) and 521a and 521b (for Core Network 520) and the respective UPF entities 512a and 512b (for Core Network 510) and 522a and 522b (for Core Network 520), and two WAB nodes 530 and 540. A wired backhaul IP network 590 interconnects the base stations 501, 502 and 503 and the Core Networks 510 and 520. For instance, this wired link consists of optical fiber cable(s). As discussed above, each WAB node comprises a Mobile Termination (MT) part or unit or component (WAB-MT 531 for WAB node 530 and WAB-MT 541 for WAB node 540) and a base station part or unit or component (WAB-gNB 532 for WAB node 530 and WAB-gNB 542 for WAB node 540). WAB node 530 and WAB node 540 may also embed a UPF entity, respectively UPF entity 533 and UPF 543, as previously discussed in relation to figure 3, allowing WAB-node 530 to provide UEs 551, 552 and 561 with at least some local services, such as for instance inter-UE communication where the user data exchanged between the two UEs would be routed through UPF entity 533 instead of being routed through a UPF entity belonging to Core Network 510 or 520. In some implementations, the UPF entity of the WAB node may be configured for one or more local services. WAB node 530 is connected to the serving backhaul base station BH-BS1, also referred to as BH-gNBl, 501 through BH link 5011. WAB node 540 may be connected to the serving backhaul base station referred to as BH-gNB2, 502 through BH link 5021 or to the serving backhaul base station referred to as BH-gNB3, 503 through BH link 5031 or, in case of dual connectivity, to both the serving backhaul base station BH-gNB2, 502 through BH link 5021 and the serving backhaul base station BH-gNB3, 503 through BH link 5031. WAB-gNB 532 of WAB node 530 is also connected to UE 551 through communication link or radio link 5301 and to UE 552 through communication link or radio link 5302. Similarly, WAB-gNB 542 of WAB node 540 is also connected to UE 561 through communication link or radio link 5401. Although Figure 5 shows only one UE 561 connected to WAB node 540, it will be appreciated that there may be a plurality of UEs connected to WAB nodes of the wireless communication system. Similarly, Figure 5 shows a plurality of UEs 551, 552, connected to WAB node 530 but it will be appreciated that there may be one UE connected. WAB-gNB 532 and WAB-MT 531 may be connected to a same AMF entity (e g., AMF 51 la) or to different AMF entities belonging to the same Core Network (e.g., AMF 511a and AMF 511b) or to different Core Networks (e.g., AMF 511a and AMF 521a). Some AMF entities may be implementing WAB-specific features for managing a WAB node (e.g., advanced mobility features). Some AMF entities may not implement such features but may still be capable of serving a WAB node with a limited set of basic features. Some AMF entities may not be capable of serving a WAB node. Processes or methods for managing one or more network connections in a wireless communication system including one or more WAB (WAB) nodes, including managing the setup of an Xn communication or connection between a WAB-gNB and a RAN node such as a base station or gNB, or another WAB-gNB of another WAB node, will now be described according to one or more examples of embodiments of the present invention. Referring firstly to figure 12 which is a flow chart showing steps of a method 1200 performed at a WAB node for use in managing connectivity of the WAB node to setup a Xn connection between the WAB node and a RAN node in accordance with one or more embodiments. The WAB node includes a MT component (or part or unit) and a gNB component (or part or unit). The WAB node may be a MW AB node or a WAB node (or a 5G femto node when based on dual components MT / gNB) and the RAN node may be a base station or gNB (e.g. a BH gNB or another gNB, which may be fixed or mobile) or may be a gNB component of another WAB node. The WAB node is part of a wireless communication system which may be, for example, the wireless communication system of figure 5. With respect to the example shown in figure 5, the WAB node may be one of nodes 530, 540 and the RAN node may be one of the BH gNBs 502, 502, 503 or another one of the WAB nodes 530, 540. The RAN node may be a fixed base station, such as base station 102 of figure 1 or a mobile base station. The method 1200 as shown in and described with respect to figure 12 may be performed by software elements and / or hardware elements. Thus, for example, the method as shown in and described with respect to figure 12 may be performed by an apparatus for the WAB node including one or more processing units configured to carry out the method. The WAB node may be implemented in a RAN node 400 as shown in and described with reference to figure 4 with the method as shown in and described with respect to figure 12 being performed by one or more processing units, such as the central processing unit 402. Briefly, at step 1202, the WAB node, such as WAB node 530, performs connection setup to establish a Xn connection between the gNB component 532 of the WAB node 530 and a RAN node or neighbouring RAN node, such as backhaul gNB 501, based on information shared or communicated between the WAB node 530 and the RAN node 501. For example, the WAB node 530 performs one or more steps to establish a Xn connection between the gNB component 532 of the WAB node 530 and a RAN node 501. The connection setup process may be the Xn Setup procedure, as defined in 3GPP TS 38.423 (e.g. section 8.4.1). The information shared may include information for identifying a relationship between the WAB node 530 and the RAN node 501 (e.g. when the information is shared between the gNB component 532 of the WAB node and the RAN node 501 and / or when information is shared between the MT component 531 of the WAB node and the RAN node) and / or information for identifying a relationship between the gNB component 532 and the MT component 531 (e.g. when the information is shared between the MT component 531 of the WAB node and the RAN node 501 and or when the information is shared between the MT component 531 of the WAB node and the gNB component 532 of the WAN node). Such a relationship may be a connection has been or is to be established between the MT component 531 of the WAB node 530 and the RAN node 501. In this case, the information may indicate the MT component 531 of the WAB node 530 is co-located with the gNB component 532 and is served by the RAN node 501 to which the gNB component 532 is to establish a connection. Such a relationship may be, in the case where the RAN node is another WAB node, the WAB node and the other WAB node belong to or are part of or are bound in the same group or set of WAB nodes (e.g. a specific set or group like a Closed Access Group). The information shared may relate to or be associated with a connection established (e.g. a connection that has previously been established) between the MT component of the WAB node and the RAN node. The information shared may include at least one of the items / elements of one or more of: the WAB-MT connection information, WAB connection information, WAB neighbouring information, neighbour WAB cells list information, femto capability information, WAB colocation information, WAB group information, etc., which information is discussed in more detail below. At least some information may be shared (e.g. between the MT component 531 of the WAB node and the RAN node and / or between the MT component 531 of the WAB node and the gNB component 532) before performing connection setup to establish a Xn connection. In an example, some information is shared during or after performing connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501. For example, information may be shared during the performance of a MT connection setup as part of a reconfiguration process (such as a handover procedure or RRC setup procedure). Such information may include colocation information as described below, which colocation or co-location information may be shared by the MT component 531 with the RAN node using a MT CONNECTION SETUP message 704. Such information may include WAB-MT connection information as described below, which WAB-MT connection information may be shared by the MT component 531 with the gNB component 532. As shown in dotted lines in figure 12 (step 1201), the connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501 may be performed before the Xn connection setup process. The information shared may include at least one of: information for identifying the gNB component 532 of the WAB node 530 (e.g. when information is shared between the MT component 531 of the WAB node and the RAN node); information for identifying the MT component 531 of the WAB node 530 (e.g. when information is shared between the gNB component 532 of the WAB node and the RAN node); information for identifying a RAN node with which the MT component 531 of the WAB node 530 has established a connection (e.g. when information is shared between the MT component 531 of the WAB node and the gNB component 532). The connection setup to establish a Xn connection may be performed after a connection is established between the MT component 531 of the WAB node 530 and the RAN node 501. In this case, the information shared between the WAB node 530 and the RAN node 501 includes information for indicating the gNB component 532 is part of the WAB node 530 including the MT component 531 served by the RAN node. Information for identifying the gNB component 532 of the WAB node 530 is shared by the MT component 531 of the WAB node with the RAN node and / or information for identifying the MT component 531 of the WAB node 530 is shared by the gNB component 532 of the WAB node with the RAN node. From either information, the RAN node 501 can determine that the MT component 531 served by the RAN node 501 is collocated with the gNB component identified. In an example, the information shared includes information indicating a connection has been established between the MT component 531 of the WAB node 530 and the RAN node 501. In this case, the information may include one or more of: information (e.g. gNB identifier) for identifying the RAN node serving the MT component 531 of the WAB node 530 (e.g. when information is shared between the MT component 531 of the WAB node and the gNB component 532), information (e.g. Cell ID) for identifying the cell serving the MT component 531 of the WAB node 530 (e.g. when information is shared between the MT component 531 of the WAB node and the gNB component 532), information for identifying the gNB component 532 of the WAB node 530 (e.g. when information is shared by the gNB component 532 of the WAB node with the RAN node), information for indicating whether the MT component 531 and gNB component 532 are co-located or associated (e.g. when information is shared by the MT component 531 of the WAB node with the RAN node and / or when information is shared by the gNB component 532 of the WAB node with the RAN node). From the information shared, the gNB component 532 of the WAB node 530 can determine that a connection has been established between the RAN node 501 and the MT component 531 of the WAB node 530, which MT component 531 is co-located with the gNB component 532 (e.g. the gNB component 531 can identify the RAN node serving the MT component 531) and the RAN node 501 can determine the gNB component which is colocated or associated with a MT component served by the RAN node 501 (e.g. can identify the gNB component which is co-located or associated with the MT component 531 served by the RAN node 501). In one example, information is shared between the MT component 531 of the WAB node 530 and the gNB component 532 of the WAB node 530. In this case, performing connection setup to establish a Xn connection between the gNB component 532 of the WAB node 530 and a RAN node 501 is based on information shared or communicated between the WAB node 530 and the RAN node 501 (e.g. between the MT component 531 and the RAN node, such as in message 704, and / or between the gNB component 532 and the RAN node 501, such as in message 601) and information shared between the MT component 531 and the gNB component 532 of the WAB node (e.g. in 605). The information shared between the MT component 531 and the gNB component 532 may be based on the information shared or communicated between the WAB node 530 and RAN node 501 (e.g. from information sent by the RAN node 501 during MT connection setup to establish a connection between the MT component 531 of the WAB node 530 and a RAN node 501) or from a broadcast message (e.g. System Information Block, SIB) sent by the RAN node 501. The information shared between the MT component 531 and the gNB component 532 may include at least one of: identification information (e.g. Base Station identifier as discussed below with reference to figure 6) for identifying the RAN node serving the MT component 531 of the WAB node 530, identification information (e.g. an identifier assigned by the RAN node for the MT component 531 during the MT connection setup between the MT component 531 and the RAN node 501) for identifying the MT component 531 of the WAB node 530 associated with the connection between the MT component and the RAN node 501; identification information (e.g. Cell identifier information as discussed below with reference to figure 6) for identifying the cell serving the MT component 531 of the WAB node 530 (e.g. for identifying a cell connecting the MT component 531 of the WAB node 530 to the RAN node 501). Such information may include the WAB-MT connection information as described below. Information (such as WAB-MT connection information) may be shared between the gNB component 532 and MT component 531 of the WAB node 530 after performing connection setup to establish a connection between the MT component 531 and before performing connection setup to establish a Xn connection. In an example in the case where the RAN node is another WAB node, the information shared (between the two gNB components of the WAB nodes) includes information indicating one of the WAB node or the other WAB node is part of or belongs to or is bound to a group or set of WAB nodes (e.g. a set of bound nodes). When receiving such information from the WAB node (e.g. a first WAB node), the other WAB node (e.g. a second WAB node) may then understand that first and second WAB nodes are part of the same WAB group. In an example, performing connection setup to establish a Xn connection includes sending, by the gNB component 532 of the WAB node 530 to the RAN node 501, a request, such as CONNECTION SETUP REQUEST message 601 as discussed below with reference to figure 6 and step 1002 of figure 10, to establish a Xn connection (or initiate establishment of a connection) between the gNB component 532 of the WAB node 530 and the RAN node 501. The gNB component 532 may send the request to a RAN node identified by information, such as the WAB-MT connection information, received from the MT component 531 of the WAB node 530 (e.g. which WAB-MT connection information is received at the MT component 531 during MT connection setup). The request may include at least one of: MT identification information, such as WAB-MT identifier information as discussed below with reference to figure 6, for identifying the MT component 531 of the WAB node 530 (e.g. which has previously established a connection with the RAN node 501); WAB information , such as WAB indication information as discussed below with reference to figure 6, for indicating the gNB component 532 is part of a WAB node; neighbour WAB node information, such ^Neighbour WAB Node List'information as discussed below with reference to figure 6, for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of the WAB node (such as gNB component 542 of neighbouring WAB node 540); neighbour WAB cell information, such as List of neighbour WAB cells information as discussed below with reference to figure 6, for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring or in the vicinity of the WAB node; femto information, such aslemto capability information as discussed below with reference to figure 6, for indicating the gNB component is part of a femto node. Such information included in the request may include the WAB connection information as described below. The shared neighbour information can be used at the node receiving the shared neighbour information to update the Neighbour Cell Relation Table (NCRT). Performing connection setup to establish a Xn connection may further include receiving, at the WAB node 530 (e.g. the gNB component 532) from the RAN node 501, a response, such as a CONNECTION SETUP RESPONSE message 602 as discussed below with reference to figure 6. The response indicates the RAN node 501 either accepts or rejects the request to establish a Xn connection between the RAN node 501 and the gNB component 532 of the WAB node 530. After receiving a response accepting the request, the WAB node 530 completes the connection setup process to establish a Xn connection. Once a Xn connection is setup, UE handover can be performed faster, and resource multiplexing can be performed between the RAN node 501 and gNB component 532 to avoid or minimise interference between the two RAN nodes. The response may include WAB neighbouring information including at least one of: neighbour WAB node information, such as Neighbour WAB Node List information as discussed below with reference to figure 6, for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of the RAN node; served WAB cell information, such as List of served WAB cells or Served WAB cells List or List of served Cells NR WAB information as discussed below with reference to figure 6, for identifying one or more cells served by the RAN node for use in serving WAB nodes. In an example, performing connection setup to establish a Xn connection includes receiving, by the gNB component 532 of the WAB node 530 from a RAN node 501, a request, such as CONNECTION SETUP REQUEST message 701 as discussed below with reference to figure 7 and step 902 of figure 9, to establish a Xn connection (or initiate establishment of a connection) between the gNB component 532 of the WAB node 530 and the RAN node 501. The request may be sent after a MT connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501 has been completed. The request may include at least one of: MT identification information, such as WAB-MTidentifier information as discussed below with reference to figure 7, for identifying the MT component 531 of the WAB node 530 (e.g. which has previously established a connection with the RAN node 501); information, such as Co-location or colocation indication information as discussed below with reference to figure 7, for indicating the RAN node sending the request is serving the MT component 531 of the WAB node 501; identification information (e.g. Cell identifier information as discussed below with reference to figure 7) for identifying a cell serving the MT component 531 of the WAB node 530 (e.g. for identifying a cell connecting the MT component 531 of the WAB node 530 to the RAN node 501); neighbour WAB node information, such as Neighbour WAB Node List information as discussed below with reference to figure 7, for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of RAN node 501 (such as gNB component 542 of neighbouring WAB node 540); served WAB cell information, such as List of served WAB cells or Served WAB cells List or List of Served Cells NR WAB information as discussed below with reference to figure 7, for identifying one or more cells served by the RAN node 501 for use in serving WAB nodes. Such information included in the request may include the WAB connection information as described below with reference to figure 7. After receiving the request (and when the WAB node 530 decides to accept the request to setup a Xn connection), the WAB node 530 may then complete the connection setup to establish a Xn connection (based on the information included in the request). For example, after determining a relationship exists between the WAB node 530 and the RAN node 501 (e.g. the MT component 531 is served by the RAN node 501) based on at least information included in the request, the WAB node 530 completes the connection setup to establish a Xn connection with the RAN node 501. Once a Xn connection is setup, handover can be performed faster, and resource multiplexing can be performed between the RAN node 501 and gNB component 532 to avoid or minimise interference between the two RAN nodes. Performing connection setup to establish a Xn connection may further include sending, by the WAB node 530 (e.g. the gNB component 532) to the RAN node 501, a response, such as a CONNECTION SETUP RESPONSE message 702 as discussed below with reference to figure 7. If the WAB node accepts the request to setup a connection, the response (e.g. sent in a CONNECTION SETUP RESPONSE message 702) indicates the request has been accepted. The response may include at least one of: neighbour WAB cell information, such as Neighbour WAB cells List information as discussed below with reference to figure 7, for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring or in the vicinity of the WAB node 530 (and detected by the MT component 731 of the WAB node 530; femto information, such as such as Femto capability information as discussed below with reference to figure 7, for indicating the gNB component is part of a femto node. The response, sent by the WAB node 530 (e.g. the gNB component) may be a response rejecting the request (e.g. sent in a Xn setup failure message) and in this case, the Xn connection is not established. The WAB node may reject the request to setup a connection (e.g., connection setup failure) due to lack of processing resources in the WAN node and / or because the WAB node is mobile and is moving. When the WAB node is mobile, the WAB node 530 may decide to not setup a connection because as it is moving, the connection will be at some point or shortly not usable as communication may no longer be possible between the WAB node and the RAN node. The WAB node 530 may include information in the response message (e.g., in the Xn setup failure message) indicating a cause for the setup failure: for example, the cause may be resource optimisation. In an example, the WAB node 530 may perform a MT connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501. The MT connection setup process may be part of a connection reconfiguration process (e.g., RRC setup procedure or handover procedure). In an example, the process of section 5.3.3 of TS38.331 may be performed to establish a connection between the MT component of the WAB node and the NG-RAN network node. As part of this MT connection setup process, the WAB node 530 (e.g., the MT component 531 of the WAB node 530) may provide information associated with the gNB component 532 of the WAB node to the RAN node 501. For example, the MT component 531 may send the WAB colocation or co-location information in a MT CONNECTION SETUP message 704 as discussed below with reference to figure 7. The information may include at least one of: identification information, such as the WAB-gNB identifier information as discussed below with reference to figure 7, for identifying the gNB component of the WAB node; femto information, such as Femto capability information as discussed below with reference to figure 7, for indicating the gNB component 532 is part of a femto node. In the cases described above (e.g. where the WAB node 530 (e.g. gNB component 532) sends the request to establish a Xn connection and where the RAN node 501 sends the request to establish a Xn connection) information relating to a connection established between the RAN node 501 and the MT component 531 of the WAB node 530 can be shared between the gNB component 532 and the RAN node 501 which allows the RAN node to determine / identify a gNB component 532 co-located with the MT component 531 served by the RAN node and which allows the gNB component 532 to determine which RAN node is serving its co-located or collocated MT component 531 and thus, to enable a Xn connection to be established between the gNB component of the WAB node 530 and the RAN node serving the MT component of the WAB node. Since the information helps the RAN node and gNB component of the WAB node to identify that the gNB component 532 is co-located with the MT component 531 served by the RAN node, the RAN node and gNB component can determine that the gNB component 532 is close to the RAN node and that therefore negotiation of radio resource allocation is preferably performed to prevent or reduce interference resulting from the proximity of the two nodes. Additional information may also be shared between the RAN node and gNB component as discussed above which additional information can enable the MT component 531 to perform efficient cell reselection (e.g. based on the served WAB cell information), can enable the RAN node 501 to avoid another gNB component of another WAB node (particularly a mobile WAB node) as a target RAN node for MT component handover (e.g. based on the neighbour WAB node information and neighbour WAB cell information). In an example, performing connection setup to establish a Xn connection includes sending, by the gNB component 532 of the WAB node 530 to another gNB component of another WAB node (e.g. gNB component 542 of WAB node 540), a request, such as CONNECTION SETUP REQUEST message 801 as discussed below with reference to figure 8 and step 1101 of figure 11, to establish a Xn connection (or initiate establishment of a connection) between the gNB component 532 of the WAB node 530 and the gNB component 542 of the WAB node 540. The request may include at least one of: WAB information, such as WAB capability information as discussed below with reference to figure 8 and step 1101 of figure 11, for indicating the gNB component 532 is part of a WAB node; femto information such as Femto capability information as discussed below with reference to figure 8, for indicating the gNB component is part of a femto node; group information or bounding information, such as WAB group information as discussed below with reference to figure 8, for indicating the WAB node is part of or belongs to or is bound to a group or set of WAB nodes (e.g. a specific set or group). The WAB group information may be an identifier for the group of WAB nodes, such as the CAG ID. The group of WAB nodes may include a group of preferred WAB nodes, which preferred nodes may be preferred target nodes for another WAB node in the group (e.g. when performing handover). Such information included in the request may include the WAB connection information as described below with reference to figure 8. Performing connection setup to establish a Xn connection may further include receiving, at the gNB component 532 of the WAB node 530 from the other gNB component 542 of the other WAB node 540, a response. The response may be the CONNECTION SETUP RESPONSE message 802 as described below with reference to figure 8. The response may include group information, such as WAB group information as discussed below with reference to figure 8, for indicating the other WAB node is part of a group of WAB nodes. After determining the other WAB node 540 is part of or belongs to or is bound to the same group of WAB nodes as the WAB node based on at least the group information included in the response, completing the connection setup to establish a Xn connection. In an example, the MT component 531 of the WAB node 530 receives WAB information or capability information from one or more neighbouring RAN nodes (e.g. nodes in the vicinity of the WAB node 530), such as, in the case of figure 5, BH gNB 502, WAB node 540, BH gNB 503. The WAB information or capability information for each neighbouring RAN node includes at least one of: capability information for indicating the neighbouring RAN node is capable of supporting WAB features and connect WAB nodes; WAB indication for indicating whether the neighbouring RAN node is a WAB node; mobile WAB indication for indicating whether the neighbouring RAN node is a mobile WAB node. For example, the WAB indication may indicate the neighbouring RAN node is a WAB node or may indicate the neighbouring RAN node is not a WAB node. The WAB indication may be provided in one field or Information Element (IE) with different values depending on whether the RAN node is a WAB node or not or may be provided in separate fields / IEs: one field / IE for indicating a WAB node and one field / IE for indicating the RAN node is not a WAB node. Alternatively, the WAB indication may only be provided in one field or IE if the RAN node is a WAB node. The mobile WAB indication may in a similar manner be one field / IE, two separate fields / IEs or the mobile WAB indication may only be provided in one field or IE if the WAB node is a mobile WAB node. The MT component 531 of the WAB node 530 may send information associated with the one or more neighbouring RAN nodes, wherein the information includes, for each of the one or more neighbouring RAN nodes based on WAB information received from the one or more neighbouring RAN nodes and measurements performed at the MT component 531 on signals received from the one or more neighbouring RAN nodes, at least one of: information for indicating the neighbouring RAN node is capable of supporting WAB features and connect WAB nodes, information for indicating a cell (e.g. neighbouring cell) is associated with a neighbouring RAN node capable of supporting WAB features and connect WAB nodes, information indicating the neighbouring RAN node is a gNB component of a WAB node, information indicating the neighbouring RAN node is a gNB component of a mobile WAB node. The information associated with the one or more neighbouring RAN nodes may be sent by the MT component 531 to a RAN node or to the gNB component 532 (e.g. as shown in message 605) collocated with the MT component 531. In an example, the information may be sent in a MEASUREMENT REPORT message 603 to the RAN node 501 serving the MT component 531 as discussed below with reference to figures 6 and 7 and may be sent in a MEASUREMENT REPORT message 603 by the WAB-MT 821 to the WAB-gNB 822 in figure 8. The RAN node 501 may use this information received from the MT component 531 to select a suitable neighbouring RAN node for handover. For example, as discussed below, the RAN node 501 may identify that one or more of the neighbouring RAN nodes to the WAB node are mobile WAB nodes based on the received information and can avoid selecting any of such mobile WAB nodes for handover to avoid any risk of the link quality between the MT component 531 of the WAB node and the gNB component of the neighbouring mobile WAB node deteriorating with movement of the mobile WAB node. Referring now also to figure 13 which is a flow chart showing steps of a method 1300 performed at a RAN node for use in managing connectivity of a WAB node to setup a Xn connection between the WAB node and the RAN node in accordance with one or more embodiments. The WAB node includes a MT component (or part or unit) and a gNB component (or part or unit). The WAB node may be a MW AB node or a WAB node (or a 5G femto node when based on dual components MT / gNB) and the RAN node may be a base station or gNB (e.g. a BE! gNB or another gNB, which may be fixed or mobile) or may be a gNB component of another WAB node. The WAB node is part of a wireless communication system which may be, for example, the wireless communication system of figure 5. With respect to the example shown in figure 5, the WAB node may be one of nodes 530, 540 and the RAN node may be one of the BH gNBs 502, 502, 503 or another one of the WAB nodes 530, 540. The RAN node may be a fixed base station, such as base station 102 of figure 1 or a mobile base station. The method 1300 as shown in and described with respect to figure 13 may be performed by software elements and / or hardware elements. Thus, for example, the method as shown in and described with respect to figure 13 may be performed by an apparatus for the RAN node including one or more processing units configured to carry out the method. The RAN node may be implemented in a RAN node 400 as shown in and described with reference to figure 4 with the method as shown in and described with respect to figure 13 being performed by one or more processing units, such as the central processing unit 402. Briefly, at step 1302, the RAN node, such as backhaul gNB 501, performs connection setup to establish a Xn connection between the gNB component 532 of the WAB node 530 and the RAN node based on information shared or communicated between the WAB node 530 and the RAN node 501. For example, the RAN node 501 performs one or more steps to establish a Xn connection between the gNB component 532 of the WAB node 530 and the 29 RAN node 501. The connection setup process may be the Xn Setup procedure, as defined in 3GPP TS 38.423 (e.g. section 8.4.1). The information shared (may include information for identifying a relationship between the WAB node 530 and the RAN node 501 (e.g. when the information is shared between the gNB component 532 of the WAB node and the RAN node 501 and / or when information is shared between the MT component 531 of the WAB node and the RAN node) and / or information for identifying a relationship between the gNB component 532 and the MT component 531 (e.g. when the information is shared between the MT component 531 of the WAB node and the RAN node 501 and or when the information is shared between the MT component 531 of the WAB node and the gNB component 532 of the WAN node). Such a relationship may be a connection has been or is to be established between the MT component 531 of the WAB node 530 and the RAN node 501. In this case, the information may indicate the MT component 531 of the WAB node 530 isco-located with the gNB component 532 and is served by the RAN node 501 to which the gNB component 532 is to establish a connection. Such a relationship may be, in the case where the RAN node is another WAB node, the WAB node and the other WAB node belong to or are part of or are bound in the same group or set of WAB nodes (e.g. a specific set or group like a Closed Access Group). The information shared may relate to or be associated with a connection established (e.g. a connection that has previously been established) between the MT component of the WAB node and the RAN node. The information shared may include at least one of the items / elements of one or more of: the WAB-MT connection information, WAB connection information, WAB neighbouring information, neighbour WAB cells list information, femto capability information, WAB colocation information, WAB group information, etc., which information is discussed in more detail below. At least some information may be shared (e.g. between the MT component 531 of the WAB node and the RAN node and / or between the MT component 531 of the WAB node and the gNB component 532) before performing connection setup to establish a Xn connection. In an example, some information is shared during or after performing connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501. For example, information may be shared during the performance of a MT connection setup as part of a reconfiguration process (such as a handover procedure or RRC setup procedure). Such information may include colocation information as described below, which colocation or co-location information may be shared with the RAN node using a MT CONNECTION SETUP message 704. Such information may include WAB-MT connection information as described below, which WAB-MT connection information may be shared by the MT component 531 with the gNB component 532. As shown in dotted lines in figure 13 (step 1301), the connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501 may be performed before the Xn connection setup process. The information shared may include at least one of: information for identifying the gNB component 532 of the WAB node 530 (e.g. when information is shared between the MT component 531 of the WAB node and the RAN node); information for identifying the MT component 531 of the WAB node 530 (e.g. when information is shared between the gNB component 532 of the WAB node and the RAN node);; information for identifying the RAN node with which the MT component 531 of the WAB node 530 has established a connection (e.g. when information is shared between the MT component 531 of the WAB node and the gNB component 532 of the WAB node). The connection setup to establish a Xn connection may be performed after a connection is established between the MT component 531 of the WAB node 530 and the RAN node 501. In this case, the information shared between the WAB node 530 and the RAN node 501 includes information for indicating the gNB component 532 is part of the WAB node 530 including the MT component 531 served by the RAN node. Information for identifying the gNB component 532 of the WAB node 530 is shared by the MT component 531 of the WAB node with the RAN node and / or information for identifying the MT component 531 of the WAB node 530 is shared by the gNB component 532 of the WAB node with the RAN node. From either information, the RAN node 501 can determine that the MT component 531 served by the RAN node 501 is collocated with the gNB component identified. In other words from the information shared, and as discussed above with reference to figure 12, the RAN node 501 can determine a gNB component which is co-located or associated with a MT component served by the RAN node 501. In an example, performing connection setup to establish a Xn connection includes receiving, at the RAN node 501 from the gNB component 532 of the WAB node 530, a request, such as CONNECTION SETUP REQUEST message 601 as discussed below with reference to figure 6 and step 1002 of figure 10, to establish a Xn connection (or initiate establishment of a connection) between the gNB component 532 of the WAB node 530 and the RAN node 501. The request may include at least one of: MT identification information, such as WAB-MTidentifier information as discussed below with reference to figure 6, for identifying the MT component 531 of the WAB node 530 (e.g. which has previously established a connection with the RAN node 501); WAB information , such as WAB indication information as discussed below with reference to figure 6, for indicating the gNB component 532 is part of a WAB node; neighbour WAB node information, such as Neighbour WAB Node List information as discussed below with reference to figure 6, for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of the WAB node (such as gNB component 542 of neighbouring WAB node 540); neighbour WAB cell information, such as List of neighbour WAB cells information as discussed below with reference to figure 6, for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring or in the vicinity of the WAB node; femto information, such as Femto capability information as discussed below with reference to figure 6, for indicating the gNB component is part of a femto node. Such information included in the request may include the WAB connection information as described below. In one aspect, the RAN node 501 determines whether to accept or reject the request to establish a Xn connection between the gNB component 532 and the RAN node 501 (e.g. based on at least the information included in the request) and sends to the WAB node 530 (e.g. gNB component 532 of the WAB node 530) a response rejecting or accepting the request. The response may be a CONNECTION SETUP RESPONSE message 602 as discussed below with reference to figure 6. If the RAN node 501 accepts the request to setup a connection, the response (e.g. sent in a CONNECTION SETUP RESPONSE message 602) indicates the request has been accepted. After sending a response accepting the request, the RAN node 501 completes the connection setup to establish a Xn connection. For example, the RAN node 501 may determine to accept the request after determining a relationship exists between the WAB node 530 and the RAN node 501 (e.g. the MT component 531 is served by the RAN node 501), based on at least information included in the request. The RAN node 501 may determine to reject the request to establish a Xn connection after determining, based on at least the information including in the request and in the case where the RAN node is another WAB node, at least one of the WAB and the other WAB node is a mobile WAB node or the WAB node and the other WAB node are not in the same group of WAB nodes. The RAN node 501 may reject the request to setup a connection (e.g. connection setup failure) due to lack of processing resources in the RAN node 501 and / or because the WAB node 530 to which the RAN node is to be connected is mobile and is moving. After determining the WAB node 530, to which the connection is to be established, is mobile, the RAN node 501 may decide to not setup a connection because as the WAB node 530 is moving, the connection will be at some point or shortly not usable as communication may no longer be possible between the WAB node and the RAN node. In such cases, the RAN node 501 decides to reject the request and the Xn connection is not established. The response rejecting the connection setup may be sent in a Xn setup failure message. The RAN node 501 may include information in the response message (e.g. in the Xn setup failure message) indicating a cause for the setup failure: for example, the cause may be resource optimisation. Once a Xn connection is setup, handover can be performed faster, and resource multiplexing can be performed between the RAN node 501 and gNB component 532 to avoid or minimise interference between the two RAN nodes. The response may include WAB neighbouring information including at least one of: neighbour WAB node information, such as Neighbour WAB Node List information as discussed below with reference to figure 6, for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of the RAN node; served WAB cell information, such as List of served WAB cells or Served WAB cells List or List ofserved Cells NR WAB information as discussed below with reference to figure 6, for identifying one or more cells served by the RAN node for use in serving WAB nodes. In an example, performing connection setup to establish a Xn connection includes sending, by the RAN node 501 to the gNB component 532 of the WAB node 530, a request, such as CONNECTION SETUP REQUEST message 701 as discussed below with reference to figure 7 and step 902 of figure 9, to establish a Xn connection (or initiate establishment of a connection) between the gNB component 532 of the WAB node 530 and the RAN node 501. The request may be sent after a MT connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501 has been completed. The request may include at least one of: MT identification information, such as WAB-MTidentifier information as discussed below with reference to figure 7, for identifying the MT component 531 of the WAB node 530 (e.g. which has previously established a connection with the RAN node 501); information, such as Co-location or colocation indication information as discussed below with reference to figure 7, for indicating the RAN node sending the request is serving the MT component 531 of the WAB node 501; identification information (e.g. Cell identifier information as discussed below with reference to figure 7) for identifying a cell serving the MT component 531 of the WAB node 530 (e.g. for identifying a cell connecting the MT component 531 of the WAB node 530 to the RAN node 501); neighbour WAB node information, such as Neighbour WAB Node List information as discussed below with reference to figure 7, for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of RAN node 501 (such as gNB component 542 of neighbouring WAB node 540); served WAB cell information, such as List of served WAB cells or Served WAB cells List or List of Served Cells NR WAB information as discussed below with reference to figure 7, for identifying one or more cells served by the RAN node 501 for use in serving WAB nodes. Such information included in the request may include the WAB connection information as described below with reference to figure 7. After sending the request, the RAN node 510 may then complete the connection setup to establish a Xn connection (based on the information included in the request). For example, after determining a relationship exists between the WAB node 530 and the RAN node 501 (e.g. the MT component 531 is served by the RAN node 501), the RAN node 501 sends the request and completes the connection setup to establish a Xn connection with the gNB component 532 of the RAN node 501. Once a Xn connection is setup, handover can be performed faster, and resource multiplexing can be performed between the RAN node 501 and gNB component 532 to avoid or minimise interference between the two RAN nodes. Performing connection setup to establish a Xn connection may further include receiving, at the RAN node 501 from the WAB node 530 (e.g. the gNB component 532), a response, such as a CONNECTION SETUP RESPONSE message 702 as discussed below with reference to figure 7. The response may include at least one of: neighbour WAB cell information, such as Neighbour WAB cells List information as discussed below with reference to figure 7, for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring or in the vicinity of the WAB node 530 (and detected by the MT component 731 of the WAB node 530; femto information, such as such as Femto capability information as discussed below with reference to figure 7, for indicating the gNB component is part of a femto node. In an example, the RAN node 501 may perform a MT connection setup to establish a connection between the MT component 531 of the WAB node 530 and the RAN node 501. The MT connection setup process may be part of a connection reconfiguration process (e.g. RRC setup procedure or handover procedure). As part of this MT connection setup process, the RAN node 501 may receive from the WAB node 530 (e.g. from the MT component 531 of the WAB node 530) information associated with the gNB component 532 of the WAB node. For example, the RAN node may receive from the MT component 531 WAB colocation or co-location information sent in a MT CONNECTION SETUP message 704 as discussed below with reference to figure 7. The information may include at least one of: identification information, such as the WAB-gNB identifier information as discussed below with reference to figure 7, for identifying the gNB component of the WAB node; femto information, such as Femto capability information as discussed below with reference to figure 7, for indicating the gNB component 532 is part of a femto node. The RAN node 501 may send the request to a gNB component 532 of a WAB node 530 identified by information, such as the colocation or co-location information, received from the WAB node 530 (e.g. during MT connection setup). In the cases described above (e.g. where the RAN node 501 receives the request to establish a Xn connection and where the RAN node 501 sends the request to establish a Xn connection) information relating to a connection established between the RAN node 501 and the MT component 531 of the WAB node 530 can be shared between the gNB component 532 and the RAN node 501 which allows the RAN node to determine / identify a gNB component 532 co-located with the MT component 531 served by the RAN node and which allows the gNB component 532 to determine which RAN node is serving its co-located or collocated MT component 531 and thus, to enable a Xn connection to be established between the gNB component of the WAB node 530 and the RAN node serving the MT component of the WAB node. Since the information helps the RAN node and gNB component of the WAB node to identify that the gNB component 532 is co-located with the MT component 531 served by the RAN node, the RAN node and gNB component can determine that the gNB component 532 is close to the RAN node and that therefore negotiation of radio resource allocation is preferably performed to prevent or reduce interference resulting from the proximity of the two nodes. In an example in the case where the RAN node is another gNB component of another WAB node (e.g. gNB component 542 of WAB node 540), performing connection setup to establish a Xn connection includes receiving, at the RAN node (e,g, the other gNB component 542) from the gNB component 532 of the WAB node 530, a request, such as CONNECTION SETUP REQUEST message 801 as discussed below with reference to figure 8 and step 1101 of figure 11, to establish a Xn connection (or initiate establishment of a connection) between the gNB component 532 of the WAB node 530 and the gNB component 542 of the WAB node 540. The request may include at least one of: WAB information, such as WAB capability information as discussed below with reference to figure 8 and step 1101 of figure 11, for indicating the gNB component 532 is part of a WAB node; femto information such as Femto capability information as discussed below with reference to figure 8, for indicating the gNB component is part of a femto node; group information or bounding information, such as WAB group information as discussed below with reference to figure 8, for indicating the WAB node is part of or belongs to or is bound to a group of WAB nodes (e.g. a specific set or group). The WAB group information may be an identifier for the group of WAB nodes, such as the CAG ID. The group of WAB nodes may include a group of preferred WAB nodes, which preferred nodes may be preferred target nodes for another WAB node in the group (e.g. when performing handover). Such information included in the request may include the WAB connection information as described below with reference to figure 8. After determining the WAB node 530 is part of or belongs to or is bound to the same group of WAB nodes as the other WAB node 540 based on at least the group information included in the request, the RAN node or other WAB node 540 completes the connection setup to establish a Xn connection. Performing connection setup to establish a Xn connection may further include sending, by the gNB component 542 to the gNB component 532 of the WAB node 530, a response. The response may be the CONNECTION SETUP RESPONSE message 802 as described below with reference to figure 8. If the other WAB node 540 accepts the request to setup a connection, the response (e g. sent in a CONNECTION SETUP RESPONSE message 802) indicates the request has been accepted. The response may include group information, such as WAB group information as discussed below with reference to figure 8, for indicating the other WAB node 540 is part of a group of WAB nodes. Such information enables the WAB node 530 to identify whether the other WAB node 540 is part of the same group as the WAB node. After determining the other WAB node 540 is part of or belongs to or is bound to the same group of WAB nodes as the WAB node based on at least the group information included in the response (i.e. the other WAB node 540 decides to accept the request), the other WAB node 540 completes the connection setup to establish a Xn connection. The RAN node 501 may receive from the MT component 531 of the WAB node 530 information associated with the one or more neighbouring RAN nodes, wherein the information includes, for each of the one or more neighbouring RAN nodes based on WAB information received from the one or more neighbouring RAN nodes (as discussed above with reference to figure 12), at least one of: information for indicating the neighbouring RAN node is capable of supporting WAB features and connect WAB nodes, information for indicating a cell (e.g. neighbouring cell) is associated with a neighbouring RAN node capable of supporting WAB features and connect WAB nodes, information indicating the neighbouring RAN node is a gNB component of a WAB node, information indicating the neighbouring RAN node is a gNB component of a mobile WAB node. In an example, the information may be sent in a MEASUREMENT REPORT message 603 to the RAN node 501 serving the MT component 531 as discussed below with reference to figures 6 and 7 and may be sent in a MEASUREMENT REPORT message 603 by the WAB-MT 821 to the WAB-gNB 822 in figure 8. The RAN node 501 may use this information received from the MT component 531 to select a suitable neighbouring RAN node for handover. For example, as discussed below, the RAN node 501 may identify that one or more of the neighbouring RAN nodes to the WAB node are mobile WAB nodes based on the received information and can avoid selecting any of such mobile WAB nodes for handover to avoid any risk of the link quality between the MT component 531 of the WAB node and the gNB component of the neighbouring mobile WAB node deteriorating with movement of the mobile WAB node. In accordance with another example method for use in managing connectivity of a WAB node in accordance with one or more embodiments will now be described. The method is performed at a WAB node which includes a MT component (or part or unit) and a gNB component (or part or unit). The WAB node may be a MW AB node or a WAB node (or a 5G femto node when based on dual components MT / gNB) and the RAN node may be a base station or gNB (e.g. a BH gNB or another gNB, which may be fixed or mobile) or may be a gNB component of another WAB node. The WAB node is part of a wireless communication system which may be, for example, the wireless communication system of figure 5. With respect to the example shown in figure 5, the WAB node may be one of nodes 530, 540 and the RAN node may be one of the BH gNBs 502, 502, 503 or another one of the WAB nodes 530, 540. The RAN node may be a fixed base station, such as base station 102 of figure 1 or a mobile base station. The method may be performed by software elements and / or hardware elements. Thus, for example, the method may be performed by an apparatus for a WAB node including one or more processing units configured to carry out the method. The WAB node may be implemented in a RAN node 400 as shown in and described with reference to figure 4 with the method described below being performed by one or more processing units, such as the central processing unit 402. In this example, the gNB component of the WAB node (e g. WAB-gNB 622 of WAB-node 620) provides to a RAN node (e.g. BH-gNB 610) information (e.g. co-location or colocation information as described below) for indicating the MT component of the WAB node (e.g. WAB-MT 623 of WAB-node 620) is co-located with the gNB component of the WAB node. The information may include MT identification information for identifying the MT component of the WAB node (e.g. an identifier known to or assigned by the RAN node (e.g. BH-gNB 610). The information may include the WAB-MT identifier information as discussed below with reference to figure 6. The information may be provided using the configuration update procedure (e.g. NG-RAN node Configuration Update procedure) as discussed below. For example, the information may be provided in the NG-RAN NODE CONFIGURATION UPDATE message as discussed below. The information may be provided at different stages. For example, the information may be provided after the MT component of the WAB node has established a connection to the RAN node. The information may be provided after the MT component of the WAB node has established a connection to the RAN node and during or after performing connection setup to establish a Xn connection between the gNB component of the WAB node and the RAN node (whether the Xn setup is initiated by the WAB node or the RAN node as described in figures 6 and 7). The information may be provided in a case when the MT component of the WAB node establishes a connection to the RAN node after a Xn connection has been established between the gNB component of the WAB node and the RAN node (whether the Xn setup is initiated by the WAB node or the RAN node as described in figures 6 and 7). In this last case, the information may be provided whilst the connection between the MT component and the RAN node is being established (and the WAB-gNB has the MT identification information to share with the RAN node) or after a connection has been established between the MT component of the WAB node and the RAN node. Additional information, such as that described with reference to figures 6 to 13 as herein, may also be provided by the gNB component to the RAN node with the MT identification information for identifying the MT component of the WAB node. Additional details and steps that may be apply to the methods discussed above with reference to figures 12 and 13 will now be described with reference to figures 6 to 11. Figure 9 is a flowchart of an example method 900 for managing Xn connection establishment between a WAB-gNB (e.g. gNB component of a WAB node) and an NG-RAN network node (e.g. RAN node) according to one or more embodiments of the present invention. The method 900 of Figure 9 is performed at the NG-RAN network node, or base station, or backhaul base station, or BH base station. For example, with reference to the wireless communication system shown in and described with respect to Figure 5, the NG-RAN network node performing the method 900 may be a backhaul base station, or BH base station, like BH gNB 501, BH gNB 502 or BH gNB 503 while the WAB node interacting with the NG-RAN network node may be the WAB-node 530, which comprises WAB-MT 531 and WAB-gNB 532, of WAB system 500. In one aspect, the NG-RAN network node may be a fixed base station, such as base station 102 of figure 1. In another aspect, the NG-RAN network node may be a mobile base station, such as a base station implemented in a satellite. The method 900 as shown in and described with respect to Figure 9 may be performed by software elements and / or hardware elements. The WAB node or the NG-RAN network node may be implemented in a communication device 400 as shown in and described with reference to Figure 4 with the method as shown in and described with respect to Figure 9 being performed by one or more processing units, such as the processing unit 402. Briefly, in a first step 901, a NG-RAN network node, or base station, may process the RRC connection setup of the terminal part (e.g. MT component), or WAB-MT, of a wireless access backhaul node, or WAB node. For example, the NG-RAN network node may perform a MT connection setup or MT connection setup process to establish a connection between the MT component of the WAB node and the NG-RAN network node. In an example, the process of section 5.3.3 of TS38.331 may be performed to establish a connection between the MT component of the WAB node and the NG-RAN network node. In one example, during this connection setup process, the WAB-MT may share some information related to the base station or gNB part (or component or unit), or WAB-gNB, of its WAB node. This information, which may also be referred to as a colocation or co-location information, may allow to uniquely identify said WAB-gNB. In one example, the connection setup process during which the WAB-MT may share some information related to the base station or gNB part, or WAB-gNB, of its WAB node with the NG-RAN network node, may be part of a reconfiguration process such as a handover process. In one example, the colocation information may be shared by the WAB-MT with the base station using the MT CONNECTION SETUP message 704, as discussed in Figure 7. In a second step 902, the NG-RAN network node may process the connection setup of the base station part or gNB part, or WAB-gNB, of the wireless access backhaul node. The NG-RAN network node may initiate this connection setup process by sending a CONNECTION SETUP REQUEST message 701, as discussed in Figure 7. For example, the connection setup process between the WAB-gNB and the NG-RAN network node may be as described in the Xn Setup procedure, as defined in 3GPP TS 38.423 (e.g. section 8.4.1). In one example, the NG-RAN network node may send the CONNECTION SETUP REQUEST message 701 to the WAB-gNB identified by the colocation information received from the WAB node at step 901. In one aspect, the NG-RAN network node may include in the CONNECTION SETUP REQUEST message 701 some WAB connection information, which may include some information related to the connection previously established between the terminal part of the wireless access backhaul node, or WAB-MT, and the NG-RAN network node. This WAB connection information may include at least one of an identifier of the WAB-MT; colocation information indicating that the NG-RAN network node is also serving the WAB-gNB’s WAB-MT; an identifier of the cell connecting the WAB-MT to the NG-RAN network node; a list of neighbour WAB nodes; a list of served WAB cells. In one aspect, the identifier of the WAB-MT may be assigned by the NG-RAN network node during the WAB-MT connection setup process. In one example, the identifier of the WAB-MT and / or the identifier of the cell connecting the WAB-MT to the NG-RAN network node is shared by the WAB-MT with its co-located WAB-gNB. The connection setup process between the WAB-gNB and the NG-RAN network node may be completed as described in the Xn Setup procedure, as defined in 3GPP TS 38.423. Figure 10 is a flowchart of an example method 1000 for managing Xn connection establishment between a WAB-gNB (e.g. gNB component of a WAB node) and an NG-RAN network node (e.g. RAN node) according to one or more embodiments of the present invention. The method 1000 of Figure 10 is performed at the Wireless Access Backhaul, WAB, node. For example, with reference to the wireless communication system shown in and described with respect to Figure 5, the WAB node performing the method 1000 may be the WAB-node 530, which comprises WAB-MT 531 and WAB-gNB 532, of WAB system 500, while the NG-RAN network node interacting with the WAB node performing the method 1000 may be a backhaul base station, or BH base station, like BH gNB 501, BH gNB 502 or BH gNB 503. In one aspect, the NG-RAN network node may be a fixed base station, such as base station 102 of figure 1. In another aspect, the NG-RAN network node may be a mobile base station, such as a base station implemented in a satellite. The method 1000 as shown in and described with respect to Figure 10 may be performed by software elements and / or hardware elements. The WAB node or the NG-RAN network node may be implemented in a communication device 400 as shown in and described with reference to Figure 4 with the method as shown in and described with respect to Figure 10 being performed by one or more processing units, such as the processing unit 402. Briefly, in a first step 1001, a wireless access backhaul, WAB node, may process the connection setup of its terminal part (e.g. MT component), or WAB-MT, with a NG-RAN network node, or backhaul base station, or BH base station. For example, the WAB node may perform a MT connection setup or MT connection setup process to establish a connection between the MT component of the WAB node and the NG-RAN network node. In one example, following this connection setup process, the WAB-MT may share some information related to the NG-RAN network node with the base station part (or component or unit), or WAB-gNB, of its WAB node. This information, which may also be referred to as a WAB-MT connection information, may allow the WAB-gNB to uniquely identify said NG-RAN network node. In one example, the connection setup process between the NG-RAN network node and the WAB-MT may be part of a reconfiguration process such as a handover process. In one example, the WAB-MT connection information may include at least one of: a base station identifier, a cell identifier. In a second step 1002, the WAB-gNB may process a connection setup with the NG-RAN network node. The WAB-gNB may initiate this connection setup process by sending a CONNECTION SETUP REQUEST message 601 to the NG-RAN network node, as discussed in Figure 6. For example, the connection setup process between the WAB-gNB and the NG-RAN network node may be as described in the Xn Setup procedure, as defined in 3GPP TS 38.423 (e.g. section 8.4.1). In one example, the WAB-gNB may process a connection setup with the NG-RAN network node identified by the WAB-MT connection information shared by its WAB-MT node at step 1001. In one aspect, the WAB-gNB may include in the CONNECTION SETUP REQUEST message 601 some WAB connection information, which may include some information related to the connection previously established between the terminal part of the wireless access backhaul node, or WAB-MT, and the NG-RAN network node. This WAB connection information may include at least one of: an identifier of the WAB-MT; information indicating that the WAB-gNB is part of a WAB node; a list of neighbour WAB nodes; a list of detected WAB cells; femto capability information indicating that the WAB node including the WAB-gNB is a femto node. In one aspect, the identifier of the WAB-MT may be assigned by the NG-RAN network node during the WAB-MT connection setup process and further shared by the WAB-MT with its co-located WAB-gNB. The connection setup process may be completed as described in the Xn Setup procedure, as defined in 3GPP TS 38.423. Figure 11 is a flowchart of an example method 1100 for managing Xn connection establishment between two WAB-gNBs (two gNB components of two WAB nodes) according to one or more embodiments of the present invention. The method 1100 of Figure 11 is performed at a Wireless Access Backhaul, WAB, node. For example, with reference to the wireless communication system shown in and described with respect to Figure 5, the WAB nodes performing the method 1100 may be the WAB-node 530 or first WAB node 530, which comprises WAB-MT 531 and WAB-gNB 532, of WAB system 500, and the WAB node WAB-node 540 or second WAB node 540, which comprises WAB-MT 541 and WAB-gNB 542. The method 1100 as shown in and described with respect to Figure 11 may be performed by software elements and / or hardware elements. A WAB node involved in method 1100 may be implemented in a communication device 400 as shown in and described with reference to Figure 4 with the method as shown in and described with respect to Figure 11 being performed by one or more processing units, such as the processing unit 402. Briefly, in a first step 1101, a first wireless access backhaul, WAB, node, may initiate the connection setup of its base station part, or WAB-gNB, or first WAB-gNB, with the base station part, or WAB-gNB, or second WAB-gNB, of a second wireless access backhaul, WAB, node. The first WAB-gNB may initiate this connection setup process by sending a CONNECTION SETUP REQUEST message 801 to the second WAB-gNB, as discussed in Figure 8. For example, the connection setup process between the first WAB-gNB and the second WAB-gNB may be as described in the Xn Setup procedure, as defined in 3GPP TS 38.423 (e.g. section 8.4.1). In one aspect of the invention, the first WAB-gNB may include in the CONNECTION SETUP REQUEST message 801 some WAB connection information, which may include at least one of: WAB capability information indicating that the WAB-gNB is part of a WAB node; femto capability information indicating that the first WAB node including the WAB-gNB is a femto node; and WAB group information indicating that the WAB node is part of a specific set or group of WAB nodes. Then, in a second step 1102, the first WAB-gNB may receive from the second WAB-gNB a CONNECTION SETUP RESPONSE message 802. In one aspect of the invention, the CONNECTION SETUP RESPONSE message 802 may include some information indicating that the second wireless access backhaul node belongs to a specific set of WAB nodes. The connection setup process may be completed as described in the Xn Setup procedure, as defined in 3GPP TS 38.423. Referring now also to Figure 6, which is a schematic and simplified diagram 600 illustrating example message flows for use in managing network connectivity in a wireless communication system including at least one Wireless Access Backhaul, WAB, node in accordance with one or more embodiments of the present invention and which may be used for managing Xn connection establishment between a WAB-gNB (e.g. gNB component of a WAB node) and an NG-RAN network node (e.g. RAN node) is shown. The mobile termination part (or component or unit), WAB-MT, 621 of a WAB node 620 (which may correspond to WAB node 120a of Figure 1 and WAB node 530 of Figure 5 as described above, or correspond to other descriptions of WAB node discussed herein) may perform RRC connection setup process with NG-RAN network node, or base station, or RAN node 610 (which may correspond to base station 104 of Figure 1 and BH-gNB 501 of Figure 5 as described above, or correspond to other descriptions of a NG-RAN network node discussed herein). For example, the WAB node 620 through its WAB-MT 621 may perform a MT connection setup or MT connection setup process (as shown by the dotted box 604 in figure 6) to establish a connection between the WAB-MT 621 of the WAB node 620 and the NG-RAN network node 610. In an example, the process of section 5.3.3 of TS38.331 may be performed to establish a connection between the MT component of the WAB node and the NG-RAN network node. In one example, as a result of this connection setup process, the WAB-MT may share some information, for example, WAB-MT connection information, related to the NG-RAN network node with the base station part, or WAB-gNB, of its WAB node. See, for example, 605 in figure 6. In one example, the WAB-MT connection information may include at least one of: - Base Station identifier information. This information uniquely identifies the base station 610. In one example, the Base Station identifier information may be the gNB Identifier (gNB ID), as defined in 3GPP TS 38.300. Cell identifier information. This information uniquely identifies the base station 61 O’s cell serving the WAB-MT 621. In one example, the Cell identifier information may be the Cell Identifier (NCI or Cell ID) or the Physical Cell Identifier (PCI), as defined in 3GPP TS 38.300. In one example, the WAB-MT 621 may share the Cell identifier information with WAB-gNB 622 once it has connected to the BH gNB 610. Once the WAB-MT connection setup process has completed, the WAB-gNB 622 may initiate a connection setup process to establish a Xn connection with the base station 610 by sending a CONNECTION SETUP REQUEST message 601 to the base station 610. In one example, this connection setup process may be the Xn Setup procedure, as defined in 3GPPTS 38.423. In one example, the CONNECTION SETUP REQUEST message 601 may be the XN SETUP REQUEST message, as specified in 3GPP TS 38.423. In one example, the WAB-gNB 622 may include in the CONNECTION SETUP REQUEST message 601 some WAB connection information. The WAB connection information may include at least one of: WAB-MT identifier information. This information uniquely identifies the WAB-MT 621, which connection with BH gNB 610 has been previously established. In one example, the WAB-MT identifier information may be the Radio Network Temporary Identifier (RNTI) previously assigned by the BH gNB 610 to the WAB-MT 621 during the WAB-MT connection setup process, as specified in 3GPP TS 38.300. In one example, the WAB-MT identifier information may be any one of: Cell-RNTI (C-RNTI), Temporary C-RNTI (TC-RNTI), Random Access RNTI (RA-RNTI). In one example, the WAB-MT 621 may share the WAB-MTidentifier information with WAB-gNB 622 once it has been assigned by the BH gNB 610. WAB indication information (or WAB capability information). This information is used by the WAB-gNB 621 to indicate to the base station 610 that it is the base station part of a WAB node (i.e., WAB node 620). In one example, the WAB indication information may be at least one slice identifier (e.g. at least one S-NSSAI, such as at least one S-NSSAI dedicated or assigned to WAB operation) indicating the base station is a base station part (e.g. WAB-gNB) of a WAB node or a list of one or more slice identifiers, or S-NSSAIs, as defined in 3GPP TS 24.501 section 9.11.3.37: the Network Slice Selection Assistance Information (NSSAI) information element identifies a collection of single NSSAIs (S-NSSAIs). At least one S-NSSAI in the list may be dedicated to WAB operation (e.g., as part of the subscription information for the WAB-MT 621), and this indicates that the node is a WAB-gNB; - Femto capability information. This information indicates that the WAB-gNB 622 is a Femto node, such as WAB node 130 of Figure 1. For example, the femto capability information indicates that the WAB node 620 including the WAB-gNB 621 is a femto node. - Neighbour WAB Node List information, such as, neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of the WAB node 620. This information contains a list of WAB-gNB node IDs, or a list of gNB IDs associated to WAB-gNBs, associated to WAB nodes in the neighbourhood of WAB node 620. In one example, the Neighbour WAB Node List information may be part of the Neighbour NG-RANNode List Information Element specified in 3GPP TS 38.423. In such case, the WAB-gNB 622 may add to each entry of the Neighbour NG-RANNode List Information Element associated to a WAB gNB a WAB gNB flag information. For example, a particular value, such as “1” or “0” of the WAB gNB flag for an entry indicates the NG-RAN node is a WAB gNB. In one example, the Neighbour WAB Node List information is based on some information, such as a system information block (SIB), received from other WAB-gNBs in proximity of WAB node 620 and detected by the WAB-MT 621. In one example, such information may also be shared by WAB-MT 621 with base station 610 using MEASUREMENT REPORT message 603, as discussed hereafter. - List of neighbour WAB cells information. This information contains a list of cell identifiers associated to WAB-gNBs belonging to WAB nodes in the neighbourhood of WAB node 620. In one example, the List of neighbour WAB cells information is based on some information, such as a synchronization information, received from other WAB-gNBs in proximity of WAB node 620 and detected by the WAB-MT 621. In one example, such information may also be shared by WAB-MT 621 with base station 610 using MEASUREMENT REPORT message 603, as discussed hereafter. By sharing WAB-MT identifier information and the WAB indication information with the base station 610, the WAB-gNB 622 allows the base station 610 to understand that the WAB-gNB 622 is the base station part of the WAB node 620 which also includes WAB-MT 621, which is already served by base station 610 and that it is therefore in close vicinity of WAB- gNB 622. Hence, the base station 610 may further negotiate some radio resource allocation with the WAB-gNB 622 in order to prevent the interferences that may result from the proximity of these two nodes. By sharing the Neighbour WAB Node List or the List of neighbour WAB cells information with the base station 610, the WAB-gNB 622 allows the base station 610 to identify some WAB-gNBs in proximity. The base station 610 may then further decide to avoid selecting one of these WAB-gNBs in proximity as a preferred target gNB when performing handover of WAB-MT 621, considering that the link between WAB-MT 621 and such target WAB-gNB in proximity may be lost at some point due to the unpredictable movement of the target WAB-gNB in the case the target WAB-gNB is a mobile WAB. The Neighbour WAB Node List or the List of neighbour WAB cells information may include a mobile WAB indication, such as a mobile WAB gNB flag or mobile WAB cellflag Vo indicate the NG-RAN node is a mobile WAB gNB. The base station 610 may further respond to the CONNECTION SETUP REQUEST message 601 by sending a CONNECTION SETUP RESPONSE message 602 to the WAB-gNB 622. In one example, the CONNECTION SETUP RESPONSE message 602 may be the XN SETUP RESPONSE message, as specified in 3GPP TS 38.423. In one example, the BH gNB 610 may include in the CONNECTION SETUP RESPONSE message 602 some WAB Neighbouring information. The WAB Neighbouring information may include at least one of: - Neighbour WAB Node List information, such as neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring or in the vicinity of the BH gNB 610. This information contains a list of WAB-gNB node IDs, or a list of gNB IDs associated to WAB-gNBs, associated to WAB nodes in the neighbourhood ofBHgNB610. In one example, the Neighbour WAB Node List information may be part of the Neighbour NG-RAN Node List Information Element specified in 3GPP TS 38.423. In such case, BH gNB 610 may add to each entry of the Neighbour NG-RAN Node List Information Element associated to a WAB gNB a WAB gNB flag information. For example, a particular value, such as “1” or “0” of the WAB gNB flag for an entry indicates the NG-RAN node is a WAB gNB. In one example, the Neighbour WAB Node List information is based on all or part of the following: some information received from other BH gNBs in proximity of BH gNB 610, some information received from one or more WAB-MTs, served by BH gNB 610, like WAB-MT 621. In one example, such information is shared by WAB-MT 621 using MEASUREMENT REPORT message 603, as discussed hereafter. - List of served WAB cells, or Served WAB cells List, or List of Served Cells NR WAB, information. This information contains a list of cells served by BH gNB 610 which are used for serving WAB nodes. For example, this served WAB cell information is for identifying one or more cells served by the RAN node 610 for use in serving WAB nodes. In one example, the List of served WAB cells information may be part of the List of Served Cells NR Information Element specified in 3GPP TS 38.423. In such case, BH gNB 610 may add to each entry of the List of Served Cells NR Information Element associated to a WAB gNB a WAB gNB cell flag information. For example, a particular value, such as “1” or “0” of the WAB gNB cell flag tor an entry indicates the cell served by the RAN node 610 is used for serving WAB nodes. The connection setup process may be completed as described in the Xn Setup procedure, as defined in 3GPP TS 38.423. By sharing the Neighbour WAB Node List information with the WAB-gNB 622, the BH gNB 610 allows the WAB-gNB 622 to identify some WAB-gNBs in proximity. The WAB-gNB 622 may then further decide to avoid selecting a WAB-gNB in proximity as a preferred target gNB when performing UE handover, considering that the link between the UE and such target WAB-gNB in proximity may be lost at some point due to the unpredictable movement of the target WAB-gNB in the case the target WAB-gNB is a mobile WAB. The Neighbour WAB Node List or the List of served WAB cells information may include a mobile WAB indication, such as a mobile WAB gNB flag or mobile WAB cell flag to indicate the NG-RAN node is a mobile WAB gNB. In case the WAB-MT 621 experiences backhaul link failure and has to perform a reestablishment procedure as described in TS 38.300 section 9.2.3.3, the WAB-MT 621 may advantageously rely on the List of served WAB cells information previously received by WAB-gNB 722 from the BH gNB 610 to perform efficient cell reselection. In one aspect, WAB-MT 621 may detect one or more NG-RAN network nodes in its vicinity and report on the surrounding cells it has detected to the BH gNB 610. In case the surrounding NG-RAN network nodes are broadcasting their capability to support WAB features and connect WAB nodes, for instance by broadcasting such capability information in a SIB1 message, the WAB-MT 621 may report on these NG-RAN network nodes using MEASUREMENT REPORT message 603. In one example, WAB-MT 621 may only report on the surrounding NG-RAN network nodes having capability to support WAB features and connect WAB nodes. In one example, WAB-MT 621 may indicate for each NG-RAN network node, in the MEASUREMENT REPORT message 603 its capability to support WAB features and connect WAB nodes. In one example, WAB-MT 621 may indicate for each cell reported in the MEASUREMENT REPORT message 603 if it is associated to a NG-RAN network node having capability to support WAB features and connect WAB nodes. By sharing this information with the BH gNB 610, in case BH gNB 610 has to handover the WAB-MT 621 to another NG-RAN network node, it may decide to select a target NG-RAN network node having capability to support WAB features and connect WAB nodes. In one aspect, WAB-MT 621 may detect one or more WAB-gNBs in its vicinity and report on the surrounding cells it has detected to the BH gNB 610. In case the surrounding WAB-gNBs are broadcasting an indication that they are base stations belonging to a mobile WAB node, or MW AB base stations, or MWAB-gNBs, for instance by broadcasting such capability information in a SIB1 message, WAB-MT 621 may report on these base stations using MEASUREMENT REPORT message 603. In one example, WAB-MT 621 may indicate in the MEASUREMENT REPORT message 603 if a surrounding base station belongs to a mobile WAB node or not. In one example, BH gNB 610 may record this information (e.g. information shared by the WAB node 620, such as the information included in the MEASUREMENT REPORT message 603) in the Neighbor Relation Table (NRT) described in TS 32.511. In one example, WAB-MT 621 may indicate for each cell reported in the MEASUREMENT REPORT message 603 if it is associated to a mobile WAB-gNB. Due to the mobility of a mobile WAB node, MW AB node, it may not be desirable that a MWAB-MT is handed over by its serving BH gNB to a target MWAB-gNB, as the link quality between the MWAB-MT and the target MWAB-gNB is likely to evolve or change (e.g. deteriorate) based on the actual movement of both the MWAB-MT and the target MWAB-gNB. In this respect, indicating for each cell reported in the MEASUREMENT REPORT message 603 if it is associated to a mobile WAB-gNB may allow BH gNB 610 to avoid performing the handover of WAB-MT 621 to a surrounding WAB-gNB. In one example, the WAB-gNB 622 establishes a Xn connection with the BH-gNB 610 before the connection of the WAB-MT 621 to the BH-gNB 610. In this case, the message 601 may not include any co-location information (e.g. an identifier of the WAB-MT 621). In case, the WAB-MT 621 connects to the BH-gNB 610 (e.g. after a Xn connection has been established between the WAB-gNB 622 and the BH-gNB 610), then the BH-gNB 610 becomes the NG-RAN node serving the WAB-MT 621. To perform efficient radio resource allocation, the BH-gNB 610 should know that the WAB-gNB 622 is co-located with the WAB-MT 621. For this purpose, the WAB-gNB 622 may transmit co-location information (e.g. MT identification information for identifying the MT component of the WAB node, such as an identifier of the WAB-MT 621 known by the BH-gNB 610) to the BH-gNB 610. This may be performed using the NG-RAN node Configuration Update procedure defined in TS 38.423 section 8.4.2. Thus, the message NG-RAN NODE CONFIGURATION UPDATE (defined in TS 38.423 section 9.1.3.4) may include an information element to identify the WAB-MT 621 (e.g. MT identification information for identifying the MT component 621 of the WAB node). In one example, the WAB-MT identifier information may be the Radio Network Temporary Identifier (RNTI) previously assigned by the BH gNB 610 to the WAB-MT 621 during the WAB-MT connection setup process, as specified in 3GPP TS 38.300. In one example, the WAB-MT identifier information may be any one of: Cell-RNTI (C-RNTI), Temporary C-RNTI (TC-RNTI), Random Access RNTI (RA-RNTI). In one example, the WAB-MT 621 may share the WAB-MT identifier information with WAB-gNB 622 once it has been assigned by the BHgNB 610. Referring now to Figure 7, which is a schematic and simplified diagram 700 illustrating example message flows for use in managing network connectivity in a wireless communication system including at least one Wireless Access Backhaul, WAB, node in accordance with one or more embodiments of the present invention and which may be used for managing Xn connection establishment between a WAB-gNB (e.g. gNB component of a WAB node) and an NG-RAN network node (e.g. RAN node) is shown. The mobile termination part (or component or unit), WAB-MT, 721 of a WAB node 720 (which may correspond to WAB node 120a of Figure 1 and WAB node 530 of Figure 5 as described above, or correspond to other descriptions of WAB node discussed herein) may perform RRC connection setup process with a NG-RAN network node, or base station or RAN node 710 (which may correspond to base station 104 of Figure 1 and BH-gNB 501 of Figure 5 as described above, or correspond to other descriptions of a NG-RAN network node discussed herein). For example, the WAB node 720 through its WAB-MT 721 may perform a MT connection setup or MT connection setup process to establish a connection between the WAB-MT 721 of the WAB node 720 and the NG-RAN network node 710. In an example, the process of section 5.3.3 of TS38.331 may be performed to establish a connection between the MT component of the WAB node and the NG-RAN network node. As part of this WAB-MT connection setup process, the WAB-MT 721 may share with the NG-RAN network node 710 some WAB colocation or WAB co-location information related the WAB-gNB 722 by sending a MT CONNECTION SETUP message 704 to the base station 710. In one example, the MT CONNECTION SETUP message 704 sent to the base station 710 by WAB-MT 721 may be the RRCSetupComplete message, used to confirm the successful completion of an RRC connection establishment, as specified in 3GPP TS 38.331. In one example, when the WAB-MT connection setup process is part of a connection reconfiguration process, the MT CONNECTION SETUP message 704 sent to the base station 710 by WAB-MT 721 may be the RRCReconfigurationComplete message, used to confirm the successful completion of an RRC connection reconfiguration, as specified in 3GPP TS 38.331. In other examples, other suitable messages may be used. The WAB colocation information (or WAB information for the WAB node 720 or information) shared by the WAB-MT 721 with the BH gNB 710 may include at least one of: WAB-gNB identifier information. This information uniquely identifies the WAB-gNB 722 collocated with WAB-MT 721 in WAB node 720. In one example, the WAB-gNB identifier information may be a WAB-gNB identifier, or WAB-gNB ID, which may be similar to the gNB Identifier (gNB ID), as defined in 3GPP TS 38.300. In one example, the WAB-gNB identifier information may be the gNB Identifier (gNB ID), as defined in 3GPP TS 38.300. - Femto capability information. This information indicates that the WAB-gNB 722 is a Femto node, such as WAB node 130 of Figure 1. For example, the femto capability information indicates that the WAB node 720 including the WAB-gNB 721 is a femto node. Once the WAB-MT connection setup process has completed, the BH gNB 710 may initiate a connection setup process to establish a Xn connection with the WAB-gNB 722 by sending a CONNECTION SETUP REQUEST message 701 to the WAB-gNB 722. In one example, this connection setup process may be the Xn Setup procedure, as defined in 3GPP TS 38.423. In one example, the CONNECTION SETUP REQUEST message 701 may be the XN SETUP REQUEST message, as specified in 3GPP TS 38.423. In one example, the BH gNB 710 may include in the CONNECTION SETUP REQUEST message 701 some WAB connection information related to the connection previously established between the WAB-MT 721 and the BH-gNB 710. The WAB connection information may include at least one of: WAB-MT identifier information. This information uniquely identifies the WAB-MT 721, which connection with BH gNB 710 has been previously established. In one example, the WAB-MT identifier information may be the Radio Network Temporary Identifier (RNTI) previously assigned by the BH gNB 710 to the WAB-MT 721 during the WAB-MT connection setup process, as specified in 3GPP TS 38.300. In one example, the WAB-MT identifier information may be any one of: Cell-RNTI (C-RNTI), Temporary C-RNTI (TC-RNTI), Random Access RNTI (RA-RNTI). In one example, the WAB-MT 721 may share the WAB-MT identifier information with WAB-gNB 722 once it has been assigned by the BH gNB 710. - Colocation indication information. This information indicates to the WAB-gNB 722 that NG-RAN network node sending the CONNECTION SETUP REQUEST message 701 is the BH gNB serving the WAB-MT 721 (i.e., BH gNB 710). In one example, the Colocation indication information may be a 1-bit information. Cell identifier information. This information identifies the cell connecting the WAB-MT 721 to the BHgNB 710. In one example, the Cell identifier information may be the Cell Identifier (NCI or Cell ID) or the Physical Cell Identifier (PCI), as defined in 3GPP TS 38.300. In one example, the WAB-MT 721 may share the Cell identifier information with WAB-gNB 722 once it has connected to the BH gNB 710. - Neighbour WAB Node List information. This information contains a list of WAB-gNB node IDs, or a list of gNB IDs associated to WAB-gNBs, associated to WAB nodes in the neighbourhood of BH gNB 710. In one example, the Neighbour WAB Node List information may be part of the Neighbour NG-RANNode List Information Element specified in 3GPP TS 38.423. In such case, BH gNB 710 may add to each entry of the Neighbour NG-RAN Node List Information Element associated to a WAB gNB a WAB gNB flag information. In one example, the Neighbour WAB Node List information is based on all or part of the following: some information received from other BH gNBs in proximity of BH gNB 710, some information received from one or more WAB-MTs, served by BH gNB 710, like WAB-MT 721. In one example, such information is shared by WAB-MT 721 using MEASUREMENT REPORT message 603, as discussed hereafter. - List of served WAB cells, or Served WAB cells List, or List of Served Cells NR WAB, information. This information contains a list of cells served by BH gNB 710 which are used for serving WAB nodes. For example, this served WAB cell information is for identifying one or more cells served by the RAN node 710 for use in serving WAB nodes. In one example, the List of served WAB cells information may be part of the List of Served Cells NR Information Element specified in 3GPP TS 38.423. In such case, BH gNB 710 may add to each entry of the List of Served Cells NR Information Element associated to a WAB gNB a WAB gNB cell flag information. By sharing all or part of the Cell identifier, Colocation indication or WAB-MT identifier information with the WAB-gNB 722, the BH gNB 710 allows the WAB-gNB 722 to understand that the BH gNB 710 is the BH base station serving WAB-MT 721 and that it is therefore in close vicinity of BH gNB 710. Hence, the WAB-gNB 722 may further negotiate some radio resource allocation with the BH gNB 710 in order to prevent the interferences that may result from the proximity of these two nodes. By sharing the Neighbour WAB Node List information with the WAB-gNB 722, the BH gNB 710 allows the WAB-gNB 722 to identify some WAB-gNBs in proximity. The WAB-gNB 722 may then further decide to avoid selecting a WAB-gNB in proximity as a preferred target gNB when performing UE handover, considering that the link between the UE and such target WAB-gNB in proximity may be lost at some point due to the unpredictable movement of the target WAB-gNB in the case the target WAB-gNB is a mobile WAB. The Neighbour WAB Node List or the List of served WAB cells information may include a mobile WAB indication, such as a mobile WAB gNB flag or mobile WAB cell flag to indicate the NG-RAN node is a mobile WAB gNB. In case the WAB-MT 721 experiences backhaul link failure and has to perform a reestablishment procedure as described in TS 38.300 section 9.2.3.3, the WAB-MT 721 may advantageously rely on the List of served WAB cells information previously received by WAB-gNB 722 from the BH gNB 710 to perform efficient cell reselection. The shared neighbour information can be used at the node receiving the shared neighbour information to update the Neighbour Cell Relation Table (NCRT). The WAB-gNB 722 may further respond to the CONNECTION SETUP REQUEST message 701 by sending a CONNECTION SETUP RESPONSE message 702 to the BH gNB 710. In one example, the CONNECTION SETUP RESPONSE message 702 may be the XN SETUP RESPONSE message, as specified in 3GPP TS 38.423. In one example, the WAB-gNB 722 may include in the CONNECTION SETUP RESPONSE message 702 some WAB Neighbouring information or WAB information or information for the WAB node 720. The WAB Neighbouring information may include at least one of: - Neighbour WAB Cells List information. This information contains a list of cells associated to a WAB node which have been previously detected by the WAB-MT 721. - Femto capability information. This information indicates that the WAB-gNB 722 is a Femto node, such as WAB node 130 of Figure 1. For example, the femto capability information indicates that the WAB node 720 including the WAB-gNB 721 is a femto node. In one example, the WAB-gNB 722 may include in the CONNECTION SETUP RESPONSE message 702 some WAB indication information or WAB information or information for the WAB node 720, where the WAB indication information is used by the WAB-gNB 722 to indicate to the base station 710 that it is the base station part of a WAB node (i.e. WAB node 720). In one example, the WAB indication information may be at least one slice identifier (e.g. at least one S-NSSAI, such as at least one S-NSSAI dedicated or assigned to WAB operation) indicating the base station is a base station part (e.g. WAB-gNB) of a WAB node or a list of one or more slice identifiers, or S-NSSAIs, as defined in 3GPP TS 24.501. The connection setup process may be completed as described in the Xn Setup procedure, as defined in 3GPP TS 38.423. The BH gNB 710 may advantageously rely on the WAB Neighbouring information to perform efficient radio resource allocation. In one aspect, WAB-MT 721 may detect one or more NG-RAN network nodes in its vicinity and report on the surrounding cells it has detected to the BH gNB 710. In case the surrounding NG-RAN network nodes are broadcasting their capability to support WAB features and connect WAB nodes, for instance by broadcasting such capability information in a SIB1 message, the WAB-MT 721 may report on these NG-RAN network nodes using MEASUREMENT REPORT message 603. In one example, WAB-MT 721 may only report on the surrounding NG-RAN network nodes having capability to support WAB features and connect WAB nodes. In one example, WAB-MT 721 may indicate for each NG-RAN network node, in the MEASUREMENT REPORT message 603 its capability to support WAB features and connect WAB nodes. In one example, WAB-MT 721 may indicate for each cell reported in the MEASUREMENT REPORT message 603 if it is associated to a NG-RAN network node having capability to support WAB features and connect WAB nodes. By sharing such information with the BH gNB 710, in case BH gNB 710 has to handover WAB-MT 721 to another NG-RAN network node, it may decide to select a target NG-RAN network node having capability to support WAB features and connect WAB nodes. In one aspect, WAB-MT 721 may detect one or more WAB-gNBs in its vicinity and report on the surrounding cells it has detected to the BH gNB 710. In case the surrounding WAB-gNBs are broadcasting an indication that they are base stations belonging to a mobile WAB node, or MW AB base stations, or MWAB-gNBs, for instance by broadcasting such capability information in a SIB1 message, WAB-MT 721 may report on these base stations using MEASUREMENT REPORT message 603. In one example, WAB-MT 721 may indicate in the MEASUREMENT REPORT message 603 if a surrounding base station belongs to a mobile WAB node or not. In one example, BH gNB 710 may record this information (e.g. information shared by the WAB node 720, such as the information included in the MEASUREMENT REPORT message 603) in Neighbor Relation Table (NRT) described in TS 32.511. In one example, WAB-MT 721 may indicate for each cell reported in the MEASUREMENT REPORT message 603 if it is associated to a mobile WAB-gNB. Due to the mobility of a mobile WAB node, MW AB node, it may not be desirable that a MWAB-MT is handed over by its serving BH gNB to a target MWAB-gNB, as the link quality between the MWAB-MT and the target MWAB-gNB is likely to evolve or change (e.g. deteriorate) based on the actual movement of both the MWAB-MT and the target MWAB-gNB. In this respect, indicating for each cell reported in the MEASUREMENT REPORT message 603 if it is associated to a mobile WAB-gNB may allow BH gNB 710 to avoid performing the handover of WAB-MT 721 to a surrounding WAB-gNB. Referring now to Figure 8, which is a schematic and simplified diagram 800 illustrating example message flow for use in managing network connectivity in a wireless communication system including at least one Wireless Access Backhaul, WAB, node in accordance with one or more embodiments of the present invention and which may be used for managing Xn connection establishment between two WAB-gNBs (two gNB components of two WAB nodes). The base station part (or component or unit), WAB-gNB, 822 of a WAB node 820 or a first WAB node 820 (which may correspond to WAB node 120a of Figure 1 and WAB node 530 of Figure 5 as described above, or correspond to other descriptions of WAB node discussed herein) may perform connection setup process with base station part (or component or unit), WAB-gNB, 832 of a WAB node 830 or a second WAB node 830 (which may correspond to WAB node 120b of Figure 1 and WAB node 540 of Figure 5 as described above, or correspond to other descriptions of WAB node discussed herein) to establish a Xn connection by sending a CONNECTION SETUP REQUEST message 801 to the WAB-gNB 832. In one example, this connection setup process may be the Xn Setup procedure, as defined in 3GPPTS 38.423. In one example, the CONNECTION SETUP REQUEST message 801 may be the XN SETUP REQUEST message, as specified in 3GPP TS 38.423. In one example, the WAB-gNB 822 may include in the CONNECTION SETUP REQUEST message 801 some WAB connection information, which may include at least one of: WAB capability information (or WAB indication information). This information indicates that the WAB-gNB 822 is the base station part of a WAB Node. In one example, the WAB capability information (or WAB indication information) may be at least one slice identifier (e.g. at least one S-NSSAI, such as at least one S-NSSAI dedicated or assigned to WAB operation) indicating the base station is a base station part (e.g. WAB-gNB) of a WAB node or a list of one or more slice identifiers, or S-NSSAIs, as defined in 3GPP TS 24.501; - Femto capability information. This information indicates that the WAB-gNB 822 is a Femto node, such as WAB node 130 of Figure 1. WAB group information. This information indicates that the WAB node 822 is part of a specific set or group of WAB nodes, also referred to as WAB group. In one example, a WAB group may gather all or part of the WAB nodes belonging to a same vehicle (e.g., a boat, a plane, a train). In one example, a WAB group may gather WAB nodes which are moving in one same geographical area (e.g., UAVs, helicopters, boats, planes). In one example, a WAB group may gather WAB nodes which are fixed in the same geographical area (e.g., in a building, in an area of an airport, hotel, house, etc.). In one example, the WAB group information may be a WAG group identifier, or a Closed Access Group Identifier (CAG ID), as defined in 3GPP TS 38.300. The WAB-gNB 822 may receive from the WAB-gNB 832 a CONNECTION SETUP RESPONSE message 802. The CONNECTION SETUP RESPONSE message 802 may include some information (e.g., WAB group information) indicating that the WAB-gNB 832 (e.g., WAB node 830) belongs to a specific set or group of WAB nodes. In one embodiment, the CONNECTION SETUP RESPONSE message 802 may include all of part of the WAB connection information, as defined for message 801. The connection setup process may be completed as described in the Xn Setup procedure, as defined in 3GPP TS 38.423. In one example, once the WAB-gNB 822 knows that it belongs to the same WAB group or set as the WAB-gNB 832 based on the received WAB group information, it may advantageously select the WAB-gNB 832 as a preferred target base station when performing UE handover. In one example, in case WAB-gNB 822 and WAB-gNB 832 belong to the same WAB group, the WAB-gNB 822 may perform “blind” handover to WAB-gNB 832, i.e., WAB-gNB 822 may perform handover of UEs to the WAB-gNB 832 without prior UE measurements and analysis of UE measurement reports, which leads to faster UE handover. While the above description refers to different reference numerals for the same features or elements between different figures, it does not necessarily indicate that the features or elements between the figures are different. Back to what has been disclosed so far, the establishment of Xn connections between a WAB-gNB and BH RAN nodes or between a WAB-gNB and surrounding RAN nodes is to be supported as part of 3GPP Release 19 framework. In other words, it can be considered that the establishment of Xn connections between a WAB-gNB and the BH RAN node serving the WAB-MT or between a WAB-gNB and surrounding RAN nodes is supported. It can follow legacy procedures, but addition of new information in these legacy procedures is not precluded. Considering Xn Connection Setup between a WAB-gNB and the BH RAN node serving the WAB-MT: For instance, to support coordination for resource multiplexing between a WAB-gNB and a (WAB-aware) BH RAN node, the co-location between the WAB-gNB and the WAB-MT should be known by the BH RAN node serving the WAB-MT. Also, the BH RAN node serving the WAB-MT of a WAB node should be known by the WAB-gNB co-located with the WAB-MT. Thus, as previously discussed in relation with figures 6 to 13, some Xn procedures, for instance the Xn setup procedure, may be enhanced to support the indication of the co-location of WAB-MT / WAB-gNB in a WAB-node and / or the identification of a BH RAN node serving a WAB-MT. Moreover, the Xn setup procedure may be initiated either by the WAB-gNB or by the BH RAN node serving the WAB-MT. To summarize the above statements: - some Xn procedures, e.g., Xn setup procedure, may be enhanced to support the sharing of some WAB-MT / WAB-gNB co-location information. some Xn procedures, e.g., Xn setup procedure, may be enhanced to allow a WAB-gNB to identify the BH RAN node serving a WAB-MT. the Xn setup procedure may be initiated either by the WAB-gNB or by the BH RAN node serving the WAB-MT. In other words, to support coordination for resource multiplexing between a WAB-gNB and a (WAB-aware) BH RAN node serving the WAB-MT, the BH RAN node should have the knowledge of which WAB-MT is collocated with the WAB-gNB while the WAB-gNB should know the BH RAN node serving the WAB-MT it is collocated with. Thus, the Xn setup procedure may be enhanced so that the XN SETUP REQUEST message sent by a WAB-gNB includes information on its co-located WAB-MT. However, the Xn setup procedure may be initiated either by the WAB-gNB or by the BH RAN node serving the WAB-MT. Thus, the XN SETUP RESPONSE message sent by a WAB-gNB may also include the information on its co-located WAB-MT. Thus, the XN SETUP REQUEST and XN SETUP RESPONSE messages sent by a WAB-gNB to the BH RAN node serving the WAB-MT include information on its co-located WAB-MT. Besides, a WAB-gNB may already have established a Xn connection with a NG-RAN node before this NG-RAN node becomes the BH RAN node serving the co-located WAB-MT (e.g., before the handover of the WAB-MT toward this NG-RAN node). Therefore, a WAB-gNB should be able to provide co-location information to a BH RAN node while a Xn connection is already established with this BH RAN node. For this purpose, the WAB-gNB may use the NG-RAN Node Configuration Update procedure. Thus, the NG-RAN NODE CONFIGURATION UPDATE message sent by a WAB-gNB to the BH RAN node serving the WAB-MT may include information on its co-located WAB-MT. Considering Xn Connection Setup between WAB-gNBs: The establishment of Xn connection between two WAB-gNBs is not precluded. In the context of two WAB-gNBs on top of two different vehicles having completely different trajectories, the interest of establishing Xn connection between these WAB-gNBs would be limited. However, when considering vehicles embedding several WAB nodes - e.g., a cruise ship or a train - establishing Xn connections between the WAB-gNBs bound to a same vehicle would become relevant. For instance, for the served UEs moving inside the vehicle, the handover from one WAB-gNB to another could be facilitated by having Xn connection between the source and target WAB-gNBs. Thus, it seems interesting not to preclude the establishment of Xn connections between WAB-gNBs as such connections may be relevant for some WAB deployments. Therefore, the establishment of Xn connections between WAB-gNBs should be supported as part 3GPP framework. An Xn connection may be setup between any two WAB-gNBs. To allow or prevent the setup of an Xn connection between two WAB-gNBs, it is proposed to have an optional WAB indication shared between WAB-gNBs during the Xn setup procedure. Then, an optional WAB indication may be included in the XN SETUP REQUEST and the XN SETUP RESPONSE message. Considering the sharing of neighbour NG-RAN nodes: In order to ease up some further Xn connection establishment, a WAB-gNB as other NG-RAN nodes, can share neighbour information to update the Neighbour Cell Relation Table (NCRT). In particular, the shared neighbour information may include the identification of neighbour WAB cells / WAB-gNBs. Thus, the neighbour information shared between NG-RAN nodes may include the identification of neighbour WAB cells / WAB-gNBs. Considering Xn Connection Rejection: A WAB-gNB may, for some WAB specific reasons (e.g., preventing Xn connection between WAB gNBs, mobility constraints ...), reject an Xn setup request received from another NG-RAN node, by issuing an XN SETUP FAILURE message, which includes the cause of rejection. Thus, a new cause value is introduced, to be used by a WAB-gNB in the XN SETUP FAILURE message to reject a Xn setup request for WAB specific reason. Reference to MW AB node / device, or mobile WAB node / device, throughout the description should be considered to also refer to WAB node / device. Typically, a WAB node may be understood to refer particularly but not exclusively to the node / device being non-mobile, i.e., disposed to a fixed, i.e., static, structure, for example, MW AB node 130 may be considered a WAB node 130 because it is mounted to a building. In most cases, as is understood from the forgoing, mobile may be understood to mean capable of moving, i.e., capable of changing geographical location, and still operating. For example, by being attached to a vehicle or person which is capable of moving. While the present invention has been described with reference to examples and embodiments, it is to be understood that the invention is not limited to the disclosed examples and embodiments. It will be appreciated by those skilled in the art that various changes and modification might be made without departing from the scope of the invention, as defined in the appended claims. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be advantageously used. In the preceding description, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over, as one or more instructions or code, a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. In this manner, computer-readable media generally may correspond to (1) tangible computer-readable storage media which is non-transitory or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and / or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium. By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave may be included in the definition of medium. It should be understood, however, that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but are instead directed to non-transient, tangible storage media. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

Claims

1. A method for use in managing connectivity of a wireless access backhaul, WAB, node,the WAB node including a mobile termination, MT, component and a gNB component, the method at the WAB node including:performing connection setup to establish a Xn connection between the gNB component of the WAB node and a RAN node based on information shared between the WAB node and the RAN node.

2. The method of claim 1, wherein the information shared includes information for identifying a relationship exists between the WAB node and the RAN node.

3. The method of claim 1 or claim 2, wherein the information shared includes informationrelating to a connection established between the MT component of the WAB node and the RAN node.

4. The method of any one of the preceding claims, wherein the information shared includes at least one of:information for identifying the gNB component of the WAB node;information for identifying a RAN node with which the MT component of the WAB node has established a connection.

5. The method of claim 1 or claim 2, wherein, in the case where the RAN node is another WAB node, the information shared includes information indicating one of the WAB node or the other WAB node is part of a group of WAB nodes.

6. The method of any one of the claims 1 to 4, wherein the connection setup to establish a Xn connection is performed after a connection is established between the MT component of the WAB node and the RAN node, wherein the information shared between the WAB node and the RAN node includes information for indicating the gNB component is part of the WAB node including the MT component served by the RAN node.

7. The method of any one of the claims 1 to 4, claim 6, further including:sharing information between the MT component and the gNB component of the WABnode,wherein performing connection setup to establish a Xn connection between the gNB component of the WAB node and a RAN node is based on information shared between the WAB node and the RAN node and information shared between the MT component and the gNB component of the WAB node.

8. The method of claim 7, wherein the information shared between the MT component and the gNB component of the WAB node is based on information received at the MT component in a broadcast message.

9. The method of claim 7, wherein the connection setup to establish a Xn connection is performed after a connection is established between the MT component of the WAB node and the RAN node, wherein the information shared between the MT component and the gNB component of the WAB node includes information for identifying the RAN node or cell serving the MT component.

10. The method of any one of the preceding claims, wherein at least some of the information is shared before or during performing connection setup to establish a Xn connection.

11. The method of any one of the preceding claims, wherein at least some of the information is shared after or during a connection is established between the MT component of the WAB node and the RAN node.

12. The method of claim 1, wherein the RAN node is one of:a RAN node serving the MT component of the WAB node;a RAN node neighbouring the WAB node;another gNB component of another WAB node.

13. The method of any one of the preceding claims, wherein performing connection setup to establish a Xn connection includes:sending, by the gNB component of the WAB node to the RAN node, a request to establish a Xn connection between the gNB component of the WAB node and the RAN node.

14. The method of claim 13, wherein sending comprises:after identifying a RAN node based on information received from the MT component of the WAB node, sending, by the gNB component of the WAB node to the identified RAN node, the request to establish a Xn connection between the gNB component of the WAB node and the identified RAN node.

15. The method of claim 13 or claim 14, wherein the request includes at least one of:MT identification information for identifying the MT component of the WAB node;WAB information for indicating the gNB component is part of a WAB node;neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring the WAB node;neighbour WAB cell information for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring the WAB node;femto information for indicating the gNB component is part of a femto node.

16. The method of any one of claims 13 to 15, wherein performing connection setup further includes: receiving, from the RAN node, a response accepting or rejecting the request to establish a Xn connection between the gNB component of the WAB node and the RAN node.

17. The method of claim 16, wherein performing connection setup further includes: after receiving a response accepting the request, completing the connection setup to establish a Xn connection.

18. The method of claim 16 or claim 17, wherein the response includes WAB neighbouring information including at least one of:neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring the RAN node;served WAB cell information for identifying one or more cells served by the RAN node for use in serving WAB nodes.

19. The method of any one of the preceding claims, further including performing a MT connection setup to establish a connection between the MT component of the WAB node and the RAN node.

20. The method of claim 19, further including providing, by the MT component of the WAB node to the gNB component of the WAB node, information associated with the connection between the MT component and the RAN node.

21. The method of claim 20, wherein the information includes at least one of: identification information for identifying the RAN node;identification information for identifying the MT component of the WAB node associated with the connection between the MT component and the RAN node;identification information for identifying a cell connecting the MT component of the WAB node to the RAN node.

22. The method of any one of claims 1 to 12, wherein performing connection setup includes: receiving, from a RAN node, a request to establish a Xn connection between the gNB component of the WAB node and the RAN node.

23. The method of claim 22, wherein performing connection setup further includes: completing the connection setup to establish a Xn connection.

24. The method of claim 22 or claim 23, wherein the request includes at least one of:MT identification information for identifying the MT component of the WAB node; information for indicating the RAN node sending the request is serving the MT component of the WAB node;identification information for identifying a cell connecting the MT component of the WAB node to the RAN node;neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring the RAN node;served WAB cell information for identifying one or more cells served by the RAN node for use in serving WAB nodes.

25. The method of any one of claims 22 to 24, wherein performing connection setup further includes: sending a response.

26. The method of claim 25, wherein the response includes at least one of:neighbour WAB cell information for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring the WAB node;femto information for indicating the gNB component is part of a femto node.

27. The method of any one of claims 22 to 26, further including performing a MT connection setup to establish a connection between the MT component of the WAB node and the RAN node.

28. The method of claim 27, further including providing, by the MT component of the WAB node to the RAN node, information associated with the gNB component of the WAB node.

29. The method of claim 28, wherein the information includes at least one of: identification information for identifying the gNB component of the WAB node; femto information for indicating the gNB component is part of a femto node.

30. The method of claim 18 or claim 24, further including performing cell reselection based on the served WAB cell information.

31. The method of any one of the preceding claims, wherein performing connection setup in the case where the RAN node is another gNB component of another WAB node includes: sending, by the gNB component of the WAB node to the another gNB component of another WAB node, a request to establish a Xn connection between the gNB component of the WAB node and the other gNB component of the other WAB node.

32. The method of claim 31, wherein performing connection setup further includes: receiving, from the other gNB component of the other WAB node, a response.

33. The method of claim 32, wherein performing connection setup further includes: after determining a relationship exists between the WAB node and the other WAB node based on at least information included in the response, completing the connection setup to establish a Xn connection.

34. The method of claim 32 or claim 33, wherein the response includes group information for indicating the other WAB node is part of a group of WAB nodes.

35. The method of claim 34, wherein performing connection setup further includes:after determining the other WAB node is part of the same group of WAB nodes as the WAB node based on at least the group information included in the response, completing the connection setup to establish a Xn connection.

36. The method of any one of claims 31 to 35, wherein the request includes at least one of: WAB information for indicating the gNB component is part of a WAB node;femto information for indicating the gNB component is part of a femto node;group information for indicating the WAB node is part of a group of WAB nodes.

37. The method of any one of claims 34 to 36, further including selecting a gNB component of another WAB node as a target when performing User Equipment, UE, handover when the other WAB node is part of the same group of WAB nodes as the WAB node.

38. The method of any one of the preceding claims, further including receiving, at the MT component of the WAB node from one or more neighbouring RAN nodes, WAB information, the WAB information including, for each of the one or more neighbouring RAN nodes, at least one of:capability information for indicating the neighbouring RAN node is capable of supporting WAB features and connect WAB nodes;WAB indication for indicating the neighbouring RAN node is a WAB node;mobile WAB indication for indicating the neighbouring RAN node is a mobile WAB node.

39. The method of claim 38, further including sending, by the MT component of the WAB node, information associated with one or more neighbouring RAN nodes, wherein the information includes, for each of the one or more neighbouring RAN nodes based on received WAB information, at least one of:information for indicating the neighbouring RAN node is capable of supporting WAB features;information for indicating a cell is associated with the neighbouring RAN node capable of supporting WAB features;information for indicating the neighbouring RAN node is a gNB component of a WAB node;information for indicating the neighbouring RAN node is a gNB component of a mobile WAB node.

40. A method for use in managing connectivity of a wireless access backhaul, WAB, node, the WAB node including a mobile termination, MT, component and a gNB component, the method including:performing, at a RAN node, connection setup to establish a Xn connection between the gNB component of the WAB node and the RAN node based on information shared between the WAB node and the RAN node.

41. The method of claim 40, wherein the information shared includes information for identifying a relationship exists between the WAB node and the RAN node.

42. The method of claim 40 or claim 41, wherein the information shared includes information indicating a connection has been established between the MT component of the WAB node and the RAN node.

43. The method of any one of the preceding claims, wherein the information shared includes at least one of:information for identifying the gNB component of the WAB node;information for identifying the RAN node with which the MT component of the WAB node has established a connection.

44. The method of any one of the claims 40 to 43, wherein the connection setup to establish a Xn connection is performed after a connection is established between the MT component of the WAB node and the neighbour RAN node, wherein the information shared between the WAB node and the neighbour RAN node includes information for indicating the gNB component is part of the WAB node including the MT component served by the neighbour RAN node.

45. The method of any one of the claims 40 to 44, wherein at least some of the information is shared before or during performing connection setup to establish a Xn connection.

46. The method of any one of claims 40 to 45, wherein at least some of the information is shared after or during a connection is established between the MT component of the WAB node and the RAN node.

47. The method of claim 40, wherein the RAN node is one of:a RAN node serving the MT component of the WAB node;a RAN node neighbouring the WAB node;another gNB component of another WAB node.

48. The method of any one of the preceding claims, wherein performing connection setup includes:receiving, at the RAN node from the gNB component of the WAB node, a request to establish a Xn connection between the gNB component of the WAB node and the RAN node.

49. The method of claim 48, wherein the request includes at least one of:MT identification information for identifying the MT component of the WAB node;WAB information for indicating the gNB component is part of a WAB node;neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring the WAB node;neighbour WAB cell information for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring the WAB node;femto information for indicating the gNB component is part of a femto node.

50. The method of any one of claims 48 to 49, wherein performing connection setup further includes: sending, by the RAN node to the WAB node, a response accepting or rejecting the request to establish a Xn connection between the gNB component of the WAB node and the RAN node.

51. The method of any one of claims 48 to 50, wherein performing connection setup further includes:after determining a relationship exists between the WAB node and the RAN node based on at least information included in the request, sending a response accepting the request;completing the connection setup to establish a Xn connection.

52. The method of claim 50, wherein performing connection setup further includes determining to reject the request to establish a Xn connection between the gNB component of the WAB node and the RAN node after determining, based on at least information included in the request and in the case the RAN node is another WAB node, at least one of the WAB node and the other WAB is a mobile WAB node or the WAB node and the other WAB node are not in the same group of WAB nodes.

53. The method of any one of claims 50 to 52, wherein the response includes WAB neighbouring information including at least one of:neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring the neighbour RAN node;served WAB cell information for identifying one or more cells served by the neighbour RAN node for use in serving WAB nodes.

54. The method of any one of claims 40 to 47, wherein performing connection setup includes:sending, by the RAN node to the WAB node, a request to establish a Xn connection between the gNB component of the WAB node and the RAN node.

55. The method of claim 54, wherein the request includes at least one of:MT identification information for identifying the MT component of the WAB node; information for indicating the RAN node sending the request is serving the MT component of the WAB node;identification information for identifying a cell connecting the MT component of the WAB node to the RAN node;neighbour WAB node information for identifying one or more gNB components of WAB nodes neighbouring the RAN node;served WAB cell information for identifying one or more cells served by the RAN node for use in serving WAB nodes.

56. The method of claim 55, further including selecting a RAN node as a target when performing handover based on the neighbour WAB node information.

57. The method of any one of claims 54 to 56, wherein performing connection setup further includes:completing the connection setup to establish a Xn connection.

58. The method of any one of claims 54 to 57, wherein performing connection setup further includes: receiving a response.

59. The method of claim 58, wherein the response includes at least one of:neighbour WAB cell information for identifying one or more cells associated with one or more gNB components of WAB nodes neighbouring the WAB node;femto information for indicating the gNB component is part of a femto node.

60. The method of any one of claims 54 to 59, wherein sending comprises:after identifying a gNB component of a WAB node based on information received from the WAB node, sending, by the RAN node to the identified gNB component of the WAB node, the request to establish a Xn connection between the gNB component of the WAB node and the identified RAN node.

61. The method of any one of claims 40 to 60, further including performing a MT connection setup to establish a connection between the MT component of the WAB node and the RAN node.

62. The method of claim 61, further including receiving, at the RAN node from the MT component of the WAB node, information associated with the gNB component of the WAB node.

63. The method of claim 62, wherein the information includes at least one of:identification information for identifying the gNB component of the WAB node;femto information for indicating the gNB component is part of a femto node.

64. The method of any one of claims 40 to 45, in the case where the RAN node is another gNB component of another WAB node, wherein performing connection setup includes:receiving, by the other gNB component of the WAB node from the gNB component of the WAB node, a request to establish a Xn connection between the gNB component of the WAB node and the other gNB component of the other WAB node.

65. The method of claim 64, wherein the request includes at least one of:WAB information for indicating the gNB component is part of a WAB node;femto information for indicating the gNB component is part of a femto node;group information for indicating the WAB node is part of a group of WAB nodes.

66. The method of claim 65, wherein performing connection setup further includes:after determining the WAB node is part of the same group of WAB nodes as the other WAB node based on at least the group information included in the request, completing the connection setup to establish a Xn connection.

67. The method of any one of claims 64 to 66, wherein performing connection setup further includes sending, to the gNB component of the WAB node, a response including group information for indicating the other WAB node is part of a group of WAB nodes.

68. The method of any one of claims 40 to 67, further including receiving, at the RAN node from the MT component of the WAB node, information associated with one or more neighbouring RAN nodes, wherein the information includes, for each of the one or more neighbouring RAN nodes, at least one of:information for indicating the neighbouring RAN node is capable of supporting WAB features;information for indicating a cell is associated with the neighbouring RAN node capable of supporting WAB features;information for indicating the neighbouring RAN node is a gNB component of a WAB node;information for indicating the neighbouring RAN node is a gNB component of a mobile WAB node.

69. The method of claim 68, further including selecting a RAN node as a target when performing handover based on the received information.

70. A method for use in managing connectivity of a wireless access backhaul, WAB, node, the WAB node including a mobile termination, MT, component and a gNB component, the method at the WAB node including:providing, by the gNB component of the WAB node to a RAN node, information for indicating the MT component of the WAB node is co-located with the gNB component of the WAB node.

71. The method of claim 70, wherein providing includes:providing, by the gNB component of the WAB node to a RAN node after the MT component of the WAB node has established a connection to the RAN node, information for indicating the MT component of the WAB node is co-located with the gNB component of the WAB node.

72. The method of claim 70 or claim 71, wherein providing includes,providing, by the gNB component of the WAB node to a RAN node during or after performing connection setup to establish a Xn connection between the gNB component of the WAB node and the RAN node, information for indicating the MT component of the WAB node is co-located with the gNB component of the WAB node.

73. The method of claim 70 or claim 71, wherein providing includes,providing, by the gNB component of the WAB node to a RAN node in a case when the MT component of the WAB node establishes a connection to the RAN node after a Xn connection has been established between the gNB component of the WAB node and the RAN node, information for indicating the MT component of the WAB node is co-located with the gNB component of the WAB node.

74. The method of any one of claims 70 to 73, wherein the information includes MT identification information for identifying the MT component of the WAB node.

75. A computer program comprising instructions which, when the program is executed by at least one processor unit, cause the at least one processing unit to carry out the method according to any one of claims 1 to 74.5 76. A computer-readable medium carrying a computer program according to claim 75.

77. An apparatus for a wireless access backhaul, WAB, node, the apparatus comprising: one or more processing units configured to perform the method as recited in any one of claims 1 to 39.1078. An apparatus for a RAN node, the apparatus comprising: one or more processing units configured to perform the method as recited in any one of claims 40 to 74.15

Images