First network node, second network node, third network node and methods performed thereby, for handling a failure

Abstract

A method, performed by a first network node (111), for handling a failure. The first network node (111) obtains (601) a first indication indicating occurrence of a failure in a second network node (112) operating in the wireless communications network (100), or in an interface of the second network node (112). The first network node (111) then initiates (603), responsive to obtaining (601) the first indication, interruption or reduction in power of transmission, by the second network node (112) or a third network node (113) operating in the wireless communications network (100), of at least a first set of one or more reference signals.

Description

[0001] FIRST NETWORK NODE, SECOND NETWORK NODE, THIRD NETWORK NODE AND METHODS PERFORMED THEREBY, FOR HANDLING A FAILURE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to a first network node and methods performed thereby for handling a failure. The present disclosure further relates generally to a second network node and methods performed thereby, for handling the failure. The present disclosure further relates generally to a third network node and methods performed thereby, for handling the failure. The present disclosure also relates generally to computer programs and a computer-readable storage mediums, having stored thereon the computer programs to carry out these methods.

[0004] BACKGROUND

[0005] Wireless devices within a wireless communications network may be e.g., User Equipments (UEs), stations (STAs), mobile terminals, wireless terminals, terminals, and / or Mobile Stations (MS). Wireless devices are enabled to communicate wirelessly in a cellular communications network or wireless communication network, sometimes also referred to as a cellular radio system, cellular system, or cellular network. The communication may be performed e.g., between two wireless devices, between a wireless device and a regular telephone and / or between a wireless device and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the wireless communications network. Wireless devices may further be referred to as mobile telephones, cellular telephones, laptops, or tablets with wireless capability, just to mention some further examples. The wireless devices in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and / or data, via the RAN, with another entity, such as another terminal or a server.

[0006] The wireless communications network covers a geographical area which may be divided into cell areas, each cell area being served by a network node, which may be an access node such as a radio network node, radio node or a base station (BS), e.g., a Radio Base Station (RBS), which sometimes may be referred to as e.g., gNB, evolved Node B (“eNB”), “eNodeB”, “NodeB”, “B node”, Transmission Point (TP), or Base Transceiver Station (BTS), depending on the technology and terminology used. The base stations (BSs) may be of different classes such as e.g., Wide Area Base Stations, Medium Range Base Stations, Local Area Base Stations, Home Base Stations, pico base stations, etc... , based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage may be provided by the base station or radio node at a base station site, or radio node site, respectively. One base station, situated on the base station site, may serve one or several cells. Further, each base station may support one or several communication technologies. The base stations communicate over the air interface operating on radio frequencies with the wireless devices within range of the base stations. The wireless communications network may also comprise network nodes which may serve receiving nodes, such as wireless devices, with serving beams. In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or even eNBs, may be directly connected to one or more core networks. In the context of this disclosure, the expression Downlink (DL) may be used for the transmission path from the base station to the wireless device. The expression Uplink (UL) may be used for the transmission path in the opposite direction i.e., from the wireless device to the base station.

[0007] The standardization organization 3GPP is currently in the process of specifying a New Radio Interface called NR or 5G-UTRA, as well as a Fifth Generation (5G) Packet Core Network, which may be referred to as Next Generation (NG) Core Network, abbreviated as NG-CN, NGC, 5G CN or 5G Core (5GC). NG may be understood to refer to the interface / reference point between the Radio Access Network (RAN) and the CN in 5G / NR. In a 5G System (5GS), a radio base station in NR may be referred to as a gNB or 5G Node B. An NR UE may be referred to as an nUE.

[0008] One of the main goals of NR is to provide more capacity for operators to serve ever increasing traffic demands and variety of applications. Because of this, NR may be able to operate on high frequencies, such as frequencies over 6 GHz, until 60 or even 100 GHz. The expansion towards higher frequencies is expected to continue into 6th Generation (6G) networks.

[0009] Operation in higher frequencies makes it possible to use smaller antenna elements, which may enable antenna arrays with many antenna elements. Such antenna arrays may facilitate beamforming, where multiple antenna elements may be used to form narrow beams and thereby compensate for the challenging propagation properties.

[0010] Furthermore, usage of these new frequencies may be understood to provide the potential for accurate sensing, e.g., based on radar-like technology.

[0011] Sensing may be understood as a procedure whereby reflections of transmitted signals may be received in a network and processed to yield spatial knowledge of the physical environment.

[0012] A sensing system may be understood as a system which may enable to perform such a procedure, transmitting signals, detecting the reflections, and processing them to yield spatial knowledge of the physical environment. A communication system may be understood as a system within a wireless communications network which may enable communication between the system and other systems or devices within the wireless communications network.

[0013] Handover and random access

[0014] Handover (HO) may be understood to be a mobility procedure used in cellular communications, e.g., in 3GPP NR networks, by which the base stations, e.g., a gNB, serving a UE may change. The basic procedure of handover may be understood to have the base station, e.g., gNB, in control of the entire process. Handover may typically involve the following steps. Initially, the UE may report measurements of signals according to a configuration provided by the network (NW), e.g., a gNB. Next, the NW, that is, the current serving gNB, may determine whether handover to a target gNB, e.g., a new serving gNB, may be desirable, e.g., based on the reported measurements. The NW may then provide the UE a configuration to be used for communication with the target gNB. Finally, the UE may detach from the source gNB and synchronize and attach to the target gNB.

[0015] In this basic procedure, the base station, e.g., the gNB, may be understood to be in control of all aspects of the handover.

[0016] Conditional handover (CHO) may be understood to be a mobility procedure for handover introduced by 3GPP in Rel-16, as schematically represented Figure 1 and Figure 2.

[0017] Figure 1 is a signalling diagram illustrating basic operations and signalling in conditional handover. The key principles of CHO may be understood to be as follows. A preparation phase, which may be understood to involve signalling between UE and gNB and may also involve inter-gNB signalling, admission control, etc, and the execution phase, in which the UE may stop communicating with the source cell and start communicating with the target cell, of the HO, may be understood to be decoupled. In CHO, the preparation phase may take place long before the execution. During this phase, the UE may be informed of the candidate cells to perform CHO and may also be given a condition or conditions when the UE may need to execute the handover. As depicted in Figure 1 , the preparation phase may be performed in stable radio conditions. At 1, the source node 2 may send a CHO request to a potential target node 3. At 4, the potential target node 3 may send a CHO request acknowledgment to the source node 2 using a Radio Resource Control (RRC) reconfiguration. At 5, the source node 2 may send a CHO configuration to a UE 6. The CHO configuration may indicate the condition of the CHO, e.g., an A3 / A5 event, described below, as well as the RRC reconfiguration. At 7, the UE may monitor the CHO condition indicated in the CHO configuration for the target cell(s) candidates. The actual execution may be triggered by the UE 6. It may be understood to be the UE 6 that may determine at 8, based on measurements and thresholds associated with the configured conditions, that CHO may have to be executed. CHO may only be executed if certain conditions are met. Otherwise, CHO may not be executed. At 9, the UE 6 may send a CHO confirmation to the potential target node 3. At 10, the potential target node 3 may then execute a path switch and perform a UE context release.

[0018] CHO was introduced to improve the robustness of mobility since it may be understood to allow the NW and the UE to prepare the HO while in good coverage conditions while executing it only when the conditions may degrade.

[0019] Figure 2 is a signalling diagram from TS 38.300, v. 17.5.0, clause 9.2.3.4.2 showing a detailed signalling diagram for conditional handover. At 0, the handover phase may begin. The UE 21 context within the source gNB 22 may contain information regarding roaming and access restrictions which may have been provided either at connection establishment or at the last Timing Advance (TA) update, e.g., by an Access and Mobility Management Function (AMF) 23. At 1, the source gNB 22 may configure the UE 21 measurement procedures and the UE 21 may report according to the measurement configuration. At 2, the source gNB 22 may decide to use CHO. At 3, the source gNB 22 may request CHO for one or more candidate cells belonging to one target gNB 24 or other potential target candidate gNBs 25. A CHO request message may be sent for each candidate cell. At 4, admission control may be performed by the target gNB 24. Slice-aware admission control may be performed if the slice information is sent to the target gNB 24. If the PDU sessions are associated with nonsupported slices, the target gNB 24 may have to reject such PDU Sessions. At 5, the candidate gNB(s) 24, 25 may send a CHO response, HO REQUEST ACKNOWLEDGE, including configuration of CHO candidate cell(s) to the source gNB 22. The CHO response message may be sent for each candidate cell. At 6, the source gNB 22 may send an RRCReconfiguration message to the UE 21 , containing the configuration of CHO candidate cell(s) and CHO execution condition(s). CHO configuration of candidate cells may be followed by other reconfiguration from the source gNB 22. A configuration of a CHO candidate cell may not contain a Dual Active Protocol Stack (DAPS handover configuration). At 7, the UE 21 may send an RRCReconfigurationComplete message to the source gNB 22. At 7a, the handover execution phase may begin. If early data forwarding is applied, the source gNB 22 may send the EARLY STATUS TRANSFER message. At 8, the UE 21 may maintain connection with the source gNB 22 after receiving CHO configuration, and may start evaluating the CHO execution conditions for the candidate cell(s). If at least one CHO candidate cell satisfies the corresponding CHO execution condition, the UE 21 may detach from the source gNB 22, apply the stored corresponding configuration for that selected candidate cell, synchronize to that candidate cell, and complete the RRC handover procedure by sending RRCReconfigurationComplete message to the target gNB 24. The UE 21 may release stored CHO configurations after successful completion of RRC handover procedure. At 8a, handover completion may begin. At 8a / b, the target gNB 24 may send the HANDOVER SUCCESS message to the source gNB 22 to inform that the UE 21 may have successfully accessed the target cell. In return, the source gNB 22 may send the SN STATUS TRANSFER message following the principles described in step 7 of Intra-AMF 23 / User Plane Function (UPF) 26 Handover in clause 9.2.3.2.1. Late data forwarding may be initiated as soon as the source gNB 22 may receive the HANDOVER SUCCESS message. At 8c, the source gNB 22 may send the HANDOVER CANCEL message toward the other signalling connections or other candidate target gNBs 25, if any, to cancel CHO for the UE 21.

[0020] The following two events, jointly or separately, may be configured as triggers for CHO. One event may be Event A3. According to Event A3, the neighbour cell may be better than the current serving cell by an offset. The other event may be Event A5, according to which the current serving cell may degrade below a first threshold while the neighbour cell may become better than a second threshold.

[0021] Both events may involve performing measurements of the signal quality associated with the current serving cell and the neighbour cell, that is, the target cell to which the UE may change. The CHO configuration provided by the NW to the UE may indicate on which signals these measurements may have to be performed. The signals may be transmitted by the current serving and the neighbour cells. In 5G NR, two types of signals may be used to this end, as indicated in the CHO configuration. A first type of signals may be signals that may be part of a synchronization signals block (SSB). This may be sometimes referred to as the Synchronization Signals (SS) / Physical Broadcast Channel (PBCH) block. A second type of signals may be channel state information reference signals (CSI-RS).

[0022] There may be understood to be differences between SSB and CSI-RS with regards to structure, periodicity, how they may be configured, etc. However, for the purpose of this description, the differences may be understood to not be important. It may suffice to say that the UE may be configured to perform measurements on some signals and, if appropriate, trigger CHO. It may be noted also that other signal types, e.g., mobility reference signals, may be used in the same way for the same purpose.

[0023] When the UE may be accessing the new cell, either Contention-Based Random Access (CBRA), or Contention-Free Random Access (CFRA) may be used. To reduce latency, CFRA may be typically preferred. CFRA preambles may need to be reserved in all target cells, which may be expensive as the resources may be locked until the CHO may be done, and it may impact the node capacity as more processing may be needed during the time the CFRA preamble may be active / used. Therefore, it may be configured only to the limited number of UE belonging to the specific UE group requiring lower interruption.

[0024] Architecture and cloud RAN aspects

[0025] UEs may connect to the network through base stations (BSs). In the 5G NR 3GPP specifications, the corresponding logical entity may be understood to be the gNB, or eNB for LTE. The functionality of the gNB may be understood to be quite broad: from transmitting and receiving electromagnetic signals to connecting to the core network (CN). Traditionally, all or most of the gNB functionality was implemented without resorting to standardizing interfaces between different parts. However, for 5G NR 3GPP introduced a higher layer split (HLS) that may enable distributed unit (DU)-centralized unit (CU) separation and may make a cloudbased implementation of the centralized part of the gNB easier. In this higher layer split, the DU may run the lower layers of the protocol stack: the Physical layer (PHY), or parts thereof, Medium Access Control (MAC), and Radio Link Control (RLC). The CU may run the higher layers of the protocol stack. Since the protocol stack may be different for control plane (CP) and user plane (UP), it may be common to refer to the internal subdivision CU-CP and CU-UP. The CU-CP may run the Packet Data Convergence Protocol (PDCP) and RRC layers for CP and may connect to the AMF in the CN, whereas the CU-UP may run the PDCP and Service Data Adaptation Protocol (SDAP) layers for UP and may connect to the UPF in the CN.

[0026] Figure 3 is a schematic diagram illustrating this architecture and interfaces. Several interfaces have also been introduced to facilitate the communication among i) DU, which may be a Cloud DU 31 or an Integrated DU 32, ii) Cloud RAN (CR) CU-CP 33, iii) CR CU-UP 34, iv) eNB 35 and v) gNB 36: a) E1 37, the 3GPP control interface between CR CU-CP 33 and CR CU-UP 34, b) F1 , the 3GPP interface, between CU and DU in HLS, wherein F1-C 38 may be understood to be the interface between Cloud DU 31 or Integrated DU 32 and CR CU-CP 33, and F1-U 39 may be understood to be the interface between Cloud DU 31 or Integrated DU 32 and CR CU-UP 34, c) X1 , the Open-Radio Access Network (O-RAN) interface between Non-Real Time (RT) Radio Intelligent Controller or RAN Intelligent Controller (RIC) and Near- RT RIC, not depicted in Figure 3, d) X2, the 3GPP interface between eNB 35 and NR RAN in non-standalone (NSA), wherein X2-C 40 may be understood to be the interface between eNB 35 and CR CU-CP 33, and X2-U 41 may be understood to be the interface between eNB 35 and CR CU-UP 34, and e) Xn, the 3GPP interface between gNB 36 and NR RAN, wherein Xn- C 42 may be understood to be the interface between gNB 36 and CR CU-CP 33, and Xn -U 43 may be understood to be the interface between gNB 36 and CR CU-UP 34. The eNB 35, Cloud DU 31, Integrated DU 32 and gNB 36 may be understood to serve cells 44. This is illustrated in Figure 3

[0027] Figure 4 is a schematic diagram illustrating an architecture with HLS 45 and lower layer split (LLS) 46. It may be understood to also be typical to have an LLS 46 which may connect the baseband unit, e.g., the DU 47, to one or several radio units (RUs) 48, which may produce the electromagnetic signals that may be transmitted over the air. The DU 47 may be connected to the CU 49. The LLS 46 may use a proprietary interface, a standardized interface, e.g., the ORAN LLS currently being discussed and specified, or a mix of the two.

[0028] O-RAN, Near Real Time RAN Intelligent Controller and xApps O-RAN specifies a set of RAN Intelligent Controllers (RICs). The near-RT RIC may be understood to reside within a telecommunications network edge cloud or regional cloud and may be understood to be responsible for intelligent edge control of RAN nodes and resources. The near-RT RIC may be understood to control RAN elements and their resources with optimization actions that may typically take 10 milliseconds to one second to complete. Artificial Intelligence / Machine Learning (AI / ML) may be used for RIC. As a result, the operation of mobile networks that may use RIC may be expected to be streamlined and automated.

[0029] Near-RT RIC may be divided into a dedicated microservices-based application called extended application (xAPP), a Near Realtime RIC Application, and the Near-RT RIC platform part that may run multiple xAPPs at the same time. Example xApps may include handover optimization, radio link monitoring, mobility management, load balancing, slicing policy updates, traffic steering, and interference management.

[0030] The Near RT RIC may communicate with the other RAN nodes through an interface called E2. The RAN nodes in this O-RAN notation may be understood to thus be typically called E2 nodes. In this document, the E2 node terminology is not used, but the RAN Node names CLI-CP, CU-LIP and DU are used for those nodes instead. It may also be noted that O- RAN specifications may typically have a notation O- for all RAN nodes. In this document, this notation is not used but embodiments herein may be understood to be just as applicable to similar nodes, even if they may be called E2 nodes or O-CU-CP, etc.

[0031] Reliability, availability, and resilience

[0032] Delivering connectivity services tailored for business or safety critical applications may be understood to represent one of the functions that may be provided by wireless cellular networks. Such services may be usually characterized by several performance requirements, which may be formalized in a Service Level Agreement (SLA) between the Connectivity Service Provider (CSP) and their customers. It may be understood to be expected that only a fraction of the applications and users of a certain network may have such high demands, hence giving the opportunity to CSPs to differentiate their offer and optimize their use of resources based on the type of user.

[0033] A large amount of work has been laid down during 5G standardization in order to bind packets delay for specific applications and users. This work resulted, among others, in features such as Ultra Reliable Low Latency Communication (URLLC) and Quality of Service (QoS) management. These features may primarily address short-term wireless channel dynamics such as fading, they may provide prioritization tools to handle high traffic load scenarios and may help to cope with different types of interference. However, these features may typically rely on a fully functional system.

[0034] There is an increasing understanding that critical applications requirements need to also be resilient to occasional failures of network subsystems. Failures in this context may be interpreted in a wide and inclusive meaning. In addition to classic hardware component failures, a software-intensive complex system such as a wireless network may fail to deliver its service due to software bugs, incorrect specifications, undesired control actions, incorrect configurations and even interactions with humans outside of what may be specified for the system.

[0035] A toolbox for providing reliability, availability and resilience may refer to the capabilities of a communication platform to deliver a dependable and trustworthy service that may be resilient to various types of failures.

[0036] Requirements on reliability, availability, and resilience may be applied individually per service and device. In other words, only a fraction of the users served by a platform at a given time may require high levels of reliability, availability, and resilience.

[0037] Existing methods to handle mobility procedures may handle in delays, down time, and waste of network resources.

[0038] SUMMARY

[0039] As part of the development of embodiments herein, one or more problems with the existing technology will first be identified and discussed.

[0040] CHO may be initiated in two ways: when the UE may perform the corresponding measurements and may determine that CHO may have to be triggered, or after declaring Radio Link Failure (RLF), and selecting a cell for reconnecting, the UE may use CHO if the selected cell has been configured as a CHO candidate.

[0041] The first way incurs in a substantially lower service interruption time than the second one, due to the time that it takes to trigger RLF. However, the first way requires that the UE can detect the corresponding condition by means of radio measurements.

[0042] Some node failures impact immediately the transmissions used for CHO-related measurements, e.g., if the RU fails. However, the impact of other node failures on the transmissions used for CHO-related measurements, e.g., some DU failures, may be delayed, e.g., several seconds.

[0043] In some cases, a UE may declare RLF instead of triggering CHO because the corresponding RLF conditions are met before the CHO-related measurements trigger CHO.

[0044] Embodiments herein may address the problems of the existing methods just described.

[0045] According to a first aspect of embodiments herein, the object is achieved by a method performed by a first network node. The method is for handling a failure. The first network node operates in a wireless communications network. The first network node obtains a first indication. The first indication indicates occurrence of a failure in a second network node operating in the wireless communications network, or in an interface of the second network node. The first network node then initiates, responsive to the obtaining of the first indication, interruption or reduction in power of transmission, by the second network node or a third network node operating in the wireless communications network, of at least a first set of one or more reference signals.

[0046] According to a second aspect of embodiments herein, the object is achieved by a method, performed by the second network node. The method is for handling the failure. The second network node operates in the wireless communications network. The second network node detects the occurrence of the failure, in the second network node or in the interface of the second network node. The second network node sends the first indication indicating the occurrence of the failure in the second network node to the first network node operating in the wireless communications network. The second network node then receives the second indication from the first network node. The second indication indicates that transmission by the second network node or the third network node operating in the wireless communications network, of at least the first set of one or more reference signals is to be interrupted, or reduced in power.

[0047] According to a third aspect of embodiments herein, the object is achieved by a method, performed by the third network node. The method is for handling the failure. The third network node operates in the wireless communications network. The third network node receives a second indication from the first network node operating in the wireless communications network. The second indication indicates that transmission by the third network node, of at least the first set of one or more reference signals is to be interrupted, or reduced in power. The third network node then initiates, responsive to the received second indication, interruption or reduction in power of transmission, by the third network node, of at least the first set of one or more reference signals.

[0048] According to a fourth aspect of embodiments herein, the object is achieved by the first network node. The first network node may be understood to be for handling the failure. The first network node is configured to operate in the wireless communications network. The first network node is configured to obtain the first indication configured to indicate occurrence of the failure in the second network node configured to operate in the wireless communications network, or in the interface of the second network node. The first network node is also configured to initiate, responsive to obtaining the first indication, interruption or reduction in power of transmission, by the second network node or the third network node configured to operate in the wireless communications network, of at least the first set of one or more reference signals.

[0049] According to a fifth aspect of embodiments herein, the object is achieved by the second network node. The second network node may be understood to be for handling the failure. The second network node is configured to operate in the wireless communications network. The second network node is configured to detect the occurrence of the failure, in the second network node or in the interface of the second network node. The second network node is also configured to send the first indication configured to indicate the occurrence of the failure in the second network node to the first network node configured to operate in the wireless communications network. The second network node is further configured to receive the second indication from the first network node. The second indication is configured to indicate that transmission by the second network node or the third network node configured to operate in the wireless communications network, of at least the first set of one or more reference signals is to be interrupted, or reduced in power.

[0050] According to a sixth aspect of embodiments herein, the object is achieved by the third network node. The third network node may be understood to be for handling the failure. The third network node is configured to operate in the wireless communications network. The third network node is configured to receive the second indication from the first network node configured to operate in the wireless communications network. The second indication is configured to indicate that transmission by the third network node of at least the first set of one or more reference signals is to be interrupted, or reduced in power. The third network node is also configured to initiate, responsive to the second indication configured to be received, interruption or reduction in power of transmission, by the third network node, of at least the first set of one or more reference signals.

[0051] According to a seventh aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processing circuitry, cause the at least one processing circuitry to carry out the method performed by the first network node.

[0052] According to an eighth sixth aspect of embodiments herein, the object is achieved by a computer-readable storage medium, having stored thereon the computer program, comprising instructions which, when executed on at least one processing circuitry, cause the at least one processing circuitry to carry out the method performed by the first network node.

[0053] According to a ninth aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processing circuitry, cause the at least one processing circuitry to carry out the method performed by the second network node.

[0054] According to a tenth aspect of embodiments herein, the object is achieved by a computer-readable storage medium, having stored thereon the computer program, comprising instructions which, when executed on at least one processing circuitry, cause the at least one processing circuitry to carry out the method performed by the second network node.

[0055] According to an eleventh aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processing circuitry, cause the at least one processing circuitry to carry out the method performed by the third network node.

[0056] According to a twelfth aspect of embodiments herein, the object is achieved by a computer-readable storage medium, having stored thereon the computer program, comprising instructions which, when executed on at least one processing circuitry, cause the at least one processing circuitry to carry out the method performed by the third network node.

[0057] By obtaining the first indication indicating the occurrence of the failure in the second network node, or in the interface of the second network node, the first network node may be enabled to then initiate interruption or reduction in power of transmission, by the second network node or the third network node, of at least a first set of one or more reference signals.

[0058] By initiating the interruption or reduction in power of transmission of at least the first set of one or more reference signals, the first network node may enable that the second network node, or the third network node may interrupt or reduce in power of transmission at least the first set of one or more reference signals and thereby the first network node may indirectly force devices operating in the wireless operating network to trigger CHO. This may thereby enable to reduce the service interruption time by ensuring that the failures in the second network node may be quickly reflected in the transmissions on which the devices may perform the CHO-related measurements.

[0059] BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Examples of embodiments herein are described in more detail with reference to the accompanying drawings, according to the following description.

[0061] Figure 1 is a signalling diagram illustrating basic operations and signalling in conditional handover, according to existing methods.

[0062] Figure 2 is a signalling diagram from TS 38.300, v. 17.5.0, clause 9.2.3.4.2 showing a detailed signalling diagram for conditional handover, according to existing methods.

[0063] Figure 3 is a schematic diagram illustrating architecture and interfaces of an HLS, according to existing methods.

[0064] Figure 4 is a schematic diagram illustrating an architecture with HLS and LLS, according to existing methods.

[0065] Figure 5 is a schematic diagram illustrating three non-limiting examples, in panels a), b) and c), of a wireless communications network, according to embodiments herein.

[0066] Figure 6 is a flowchart depicting a method in a first network node, according to embodiments herein.

[0067] Figure 7 is a flowchart depicting a method in a second network node, according to embodiments herein. Figure 8 is a flowchart depicting a method in third network node, according to embodiments herein.

[0068] Figure 9 is a flowchart depicting a non-limiting example of a method in a first network node, according to embodiments herein.

[0069] Figure 10 is a signalling diagram depicting a non-limiting example of a method in a first network node and a second network node , according to embodiments herein.

[0070] Figure 11 is a signalling diagram depicting a non-limiting example of a method in a first network node and a third network node , according to embodiments herein.

[0071] Figure 12 is a signalling diagram depicting a non-limiting example of a method in a first network node, a second network node and a third network node, according to embodiments herein.

[0072] Figure 13 is a schematic block diagram illustrating an embodiment of a first network node, according to embodiments herein.

[0073] Figure 14 is a schematic block diagram illustrating an embodiment of a second network node, according to embodiments herein.

[0074] Figure 15 is a schematic block diagram illustrating an embodiment of a third network node, according to embodiments herein.

[0075] DETAILED DESCRIPTION

[0076] Certain aspects of the present disclosure and their embodiments address the challenges identified in the Background and Summary sections with the existing methods and provide solutions to the challenges discussed.

[0077] Embodiments herein may be understood to relate to method to trigger CHO for improving reliability, availability, and / or resilience.

[0078] Embodiments herein may be understood to relate to providing a set of embodiments for guaranteeing improved reliability, availability, and / or resilience-level service during failures of a communications system. As an abbreviated overview, some embodiments herein may comprise detecting a failure, e.g., a failure of a node, a function or an interface, or a condition that may be likely to result in a failure, e.g., overheating, use of backup power, etc., and in response, acting on the transmissions that may be used by the UEs to perform measurements related to CHO. For example, the transmissions may be stopped or gradually stopped. With this action, the NW may indirectly force the UEs to trigger CHO. This may thereby enable to reduce the service interruption time by ensuring that the failures in a node may be quickly reflected in the transmissions on which the UE may perform the CHO-related measurements.

[0079] Embodiments for cloud implementations in which different parts of the procedure may be executed by different functions are described as well. Some of the embodiments contemplated will now be described more fully hereinafter with reference to the accompanying drawings, in which examples are shown. In this section, the embodiments herein will be illustrated in more detail by a number of exemplary embodiments. Other embodiments, however, are contained within the scope of the subject matter disclosed herein. The disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. It should be noted that the exemplary embodiments herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments.

[0080] Several embodiments and examples are comprised herein. It should be noted that the embodiments and / or examples herein are not mutually exclusive. Components from one embodiment or example may be tacitly assumed to be present in another embodiment or example and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments and / or examples.

[0081] Figure 5 depicts three non-limiting examples, in panel a), panel b) and panel c), respectively, of a wireless network or wireless communications network 100, sometimes also referred to as a wireless communications system, cellular radio system, or cellular network, in which embodiments herein may be implemented. The wireless communications network 100 may be a 5G system, 5G network, or Next Gen System or network, or a newer system, e.g., a Sixth Generation (6G) system, with similar functionality. In other examples, the wireless communications network 100 may, alternatively or additionally, support other technologies such as, for example, Long-Term Evolution (LTE), e.g., LTE for Machines (LTE- M), LTE Frequency Division Duplex (FDD), LTE Time Division Duplex (TDD), LTE Half-Duplex Frequency Division Duplex (HD-FDD), LTE operating in an unlicensed band, such as LTE Licensed-Assisted Access (LAA), enhanced eLAA (eLAA), further enhanced LAA (feLAA) and / or MulteFire. The wireless communications network 100 may support Machine Type Communication (MTC), enhanced MTC (eMTC), Internet of Things (loT) and / or NarrowBand loT (NB-loT). Yet in other examples, the wireless communications network 100 may, in addition, further support other technologies such as, for example Wideband Code Division Multiple Access (WCDMA), Universal Terrestrial Radio Access (UTRA) TDD, Global System for Mobile communications (GSM) network, GSM / Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (GERAN) network, Ultra-Mobile Broadband (UMB), EDGE network, network comprising of any combination of Radio Access Technologies (RATs) such as e.g. Multi-Standard Radio (MSR) base stations, multi-RAT base stations etc., any 3rd Generation Partnership Project (3GPP) cellular network, WiFi networks, Worldwide Interoperability for Microwave Access (WiMax), or any cellular network or system. Thus, although terminology from 5G NR radio access technology may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the embodiments herein to only the aforementioned system. Embodiments herein may be understood to be applicable to other radio technologies.

[0082] In some examples, the wireless communications network 100 may include an access network, such as a radio access network (RAN), and a core network, which may include one or more core network nodes. The access network may include one or more access network nodes, e.g., which may be generally referred to as network nodes, or any other similar 3rd Generation Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes may include disaggregated implementations or portions thereof.

[0083] For example, some embodiments herein may be described in terms of a higher-layer split (HLS) architecture defined for 5G NR. In particular, embodiments herein may refer to different radio network node, e.g., gNB, functions applicable to 5G NR such as the radio unit (Rll), the distributed unit (DU), and the control unit (CU), which may be further divided in user plan (CU-UP) and control plane (CU-CP) parts. Nonetheless, embodiments herein may be applicable to other architecture options including centralized and distributed solutions.

[0084] In some embodiments, the wireless communications network 100 may include one or more Open-RAN (ORAN) network nodes. An ORAN network node may be understood to be a node in the telecommunication network that may support an ORAN specification, e.g., a specification published by the O-RAN Alliance, or any similar organization, and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network, including one or more network nodes and / or core network nodes.

[0085] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU- CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller, near-real time or non-real time, hosting software or software plug-ins, such as a near-real time control application, e.g., xApp, or a non-real time control application, e.g., rApp, or any combination thereof, the adjective “open” designating support of an ORAN specification. Any of the network node 110 and the second network node 112 may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an A1, F1, W1 , E1, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment, in which one or more network functions may be virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the O-RAN Alliance or comparable technologies. Any of the network node 110 and the second network node 112 may facilitate direct or indirect connection of one or more devices, such as the one or more devices 130 described below, such as by connecting the one or more devices 130 to the core network over one or more wireless connections.

[0086] The wireless communications network 100 may comprise a plurality of network nodes, whereof a first network node 111 , a second network node 112 and a third network node 113 are depicted in the three non-limiting examples of Figure 5. It may be understood that there may be additional network nodes comprised in the wireless communications network 100.

[0087] The third network node 113, and in some examples, any of the first network node 111 and the second network node 112 may be a radio network node. That is, a transmission point such as a radio base station, for example a gNB, or any other network node with similar features capable of serving a user equipment, such as a wireless device or a machine type communication device, in the wireless communications network 100. In some examples, any of the first network node 111 , the second network node 112, and the third network node 113 may be a distributed node, such as a virtual node in a cloud 115, as depicted for the first network node 111 and the second network node 112 in the non-limiting example depicted in panels a) and b) of Figure 5, and may perform its functions entirely on the cloud 115, or partially, in collaboration with a radio network node.

[0088] In some examples, all of the first network node 111 , the second network node 112 and at the third network node 113 may be radio network nodes.

[0089] In some examples, any of the first network node 111 and the second network node 112 may be implemented in the cloud 115.

[0090] Any of the first network node 111 , the second network node 112 and the third network node 113 may be co-localized or be the same node, that is, manage or run the same logical entity, such as the first network node 111 and the second network node 112 in panel b) of Figure 5, and the first network node 111, the second network node 112 and the third network node 113 in panel c) of Figure 5.

[0091] In particular examples of embodiments herein, the first network node 111 may be a DU, or a CR DU. The second network node 112 may be a CU or a CR CU. The third network node 113 may be an RU.

[0092] In particular examples, the first network node 111 and the second network node 112 may be the same node. In some of such examples, the first network node 111 may be a DU. The wireless communications network 100 may cover a geographical area, which in some embodiments may be divided into cell areas, wherein each cell area may be served by a radio network node, although, one radio network node may serve one or several cells. In the example of Figure 5, cells are not depicted. Any of the first network node 111 , the second network node 112, and the third network node 113 operating in the wireless communications network 100 may be of different classes, such as, e.g., macro base station, home base station or pico base station, based on transmission power and thereby also cell size. Any of the first network node 111 , the second network node 112, and the third network node 113 operating in the wireless communications network 100 may serve receiving nodes with serving beams. Any of the first network node 111 , the second network node 112, and the third network node 113 may support one or several communication technologies, and its name may depend on the technology and terminology used. Any of the first network node 111 , the second network node 112, and the third network node 113 may be directly connected to one or more core networks, e.g., to one or more network nodes in the one or more core networks.

[0093] One or more devices 130 may be comprised in the wireless communication network 100. In some examples, the one or more devices 130 may comprise a first set of devices 131, and / or a second set of devices 132. In Figure 5, the first set of devices 131 is represented by a single device and the second set of devices 132 is also represented with a single device. This may be understood to be non-limiting and in order to simplify the figure. Fewer or more wireless devices may be comprised in the wireless communication network 100. Any of the one or more devices 130, e.g., any of the devices in the first set of devices 131 and / or any of the devices in the second set of devices 132, may be a wireless device, that is, a wireless communication device such as a 5G or 6G User Equipment (UE) or nUE, or a UE, which may also be known as e.g., mobile terminal, wireless terminal and / or mobile station, a mobile telephone, cellular telephone, or laptop with wireless capability, just to mention some further examples. Any of the one or more devices 130, e.g., any of the devices in the first set of devices 131 and / or any of the devices in the second set of devices 132 comprised in the wireless communications network 100, may be, for example, portable, pocket-storable, handheld, computer-comprised, or a vehicle-mounted mobile device, enabled to communicate voice and / or data, via the RAN, with another entity, such as a server, a laptop, a Personal Digital Assistant (PDA), or a tablet, Machine-to-Machine (M2M) device, a sensor, loT device, NB-loT device, device equipped with a wireless interface, such as a printer or a file storage device, modem, or any other radio network unit capable of communicating over a radio link in a communications system. Any of the one or more devices 130, e.g., any of the devices in the first set of devices 131 and / or any of the devices in the second set of devices 132 may be enabled to communicate wirelessly in the wireless communications network 100. The communication may be performed e.g., via a RAN, and possibly the one or more core networks, which may be comprised within the wireless communications network 100.

[0094] It may be understood that the wireless communications network 100 may comprise additional network nodes, radio network nodes and / or additional devices than those depicted in Figure 5.

[0095] The first network node 111 may be configured to communicate within the wireless communications network 100 with the second network node 112 over a first link 141 , e.g., a radio link, or a wired link. The first network node 111 may be configured to communicate within the wireless communications network 100 with the third network node 113 over second link 142, e.g., a radio link, or a wired link. The third network node 113 may be configured to communicate within the wireless communications network 100 with the devices in the first set of devices 131 over a respective third link 143, e.g., a radio link. The third network node 113 may be configured to communicate within the wireless communications network 100 with the devices in the second set of devices 132 over a respective fourth link 144, e.g., a radio link.

[0096] Any of the first link 141 , the second link 142, the respective third link 143 and the respective fourth link 144, may be a direct link or may be comprised of a plurality of individual links, wherein it may go via one or more computer systems in the computer system 100, which are not depicted in Figure 5, or it may go via an optional intermediate network. The intermediate network may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network, if any, may be a backbone network or the Internet; in particular, the intermediate network may comprise two or more sub-networks, which is not shown in Figure 5.

[0097] Communication between any of the first network node 111 , the second network node 112, and the third network node 113, e.g., the different functions they may respectively manage, may take place over standardized interfaces and / or proprietary interfaces.

[0098] In general, the usage of “first”, “second”, “third” and / or “fourth”, herein may be understood to be an arbitrary way to denote different elements or entities, and may be understood to not confer a cumulative or chronological character to the nouns they modify.

[0099] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0100] Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0101] Embodiments of a method, performed by the first network node 111 , will now be described with reference to the flowchart depicted in Figure 6. The method may be understood to be computer-implemented. The method is for handling a failure. The first network node 111 operates in the wireless communications network 100.

[0102] Several embodiments are comprised herein. In some embodiments all the actions may be performed. In some embodiments, one may be optional. In Figure 6, the optional action is indicated with dashed lines. It should be noted that the examples herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description.

[0103] Action 601

[0104] In this Action 601 , the first network node 111 obtains a first indication. The first indication indicates occurrence of a failure in the second network node 112 operating in the wireless communications network 100, or in an interface of the second network node 112.

[0105] In some examples, the failure may be a failure of the hardware of the second network node 112, that is, of the physical node that may implement various functions.

[0106] In some embodiments, the failure may be of one or more functions, e.g., one or more logical functions, managed by the second network node 112.

[0107] In other embodiments, the failure may be of one or more interfaces that may connect functions or nodes.

[0108] In some embodiments, the first indication may indicate that the failure may have happened, may be happening or may be going to happen within a time period.

[0109] The first indication may indicate the failure by indicating, for example, on a condition that may be likely to result in the failure, e.g., overheating, use of backup power, etc. The first indication may be for example, an alarm, an event or performance measurement event (PM event), a watchdog, an expiration of a timer, including a response OK not arriving in the required time, a loss of connectivity, etc.

[0110] The obtaining in this Action 601 of the first indication may comprise one of: a) receiving the first indication from the second network node 112 or another network node operating in the wireless communications network 100, and b) detecting the failure. The another network node may be understood to be a network node other than that that may have experienced, may be experiencing or may experience the failure.

[0111] In some examples, the first network node 111 may be a base station, e.g., a gNB.

[0112] In some examples, each of the first network node 111 , the second network node 112 and the another network node may be different nodes. In one example, two different gNB functions may be involved. As an example, the second network node 112, or the another network node, may manage a first function, e.g., gNB function 1 , which may be a CU-LIP and may indicate the failure to the first network node 111 , which may manage a second function, e.g., a gNB function 2, which may be a DU.

[0113] The second network node 112, or the another network node, via the first function, may detect the failure, e.g., of its own, in the case of the second network node 112, or of a third function, in the case of the another network node, and may notify this to the first network node 111 , via the second gNB function. In response, the first network node 111 may, via the second gNB function, be enabled to then act on the transmissions that may be relevant for triggering CHO.

[0114] As mentioned earlier, in some examples, any of the first network node 111 , the second network node 112 and the another network node may be the same network node.

[0115] In some embodiments, an AI / ML platform run by the first network node 111 , or the node detecting the failure, that may host logic used for detecting the failure. O-RAN’s Near RT RIC may be one AI / ML platform that may host an xApp, that is, a program, that may comprise said logic. Alternatively, O-RAN’s non-RT RIC or a proprietary platform may be used for that purpose.

[0116] Action 602

[0117] Embodiments herein may be understood to aim at having the first network node 111, speed up the process by which at least a subset of the one or more devices 130 may trigger CHO in response to the detection of the failure.

[0118] This may be based on a CHO configuration having been provided to the one or more devices 130 at an earlier time. In order to speed up the process, the first network node 111, may act on the transmissions that may be relevant for triggering CHO. Such transmissions may be understood to be of signals, e.g., one or more reference signals. The one or more reference signals may be used to trigger conditional handover of the one or more devices 130. In this disclosure, SSB and CSI-RS may be used as examples of such signals, but embodiments herein may be understood to be applicable to other types of transmissions, e.g., signals, reference signals, synchronization signals, mobility signals, physical channels, sequences, etc..

[0119] In this Action 602, the first network node 111 may determine, based on the obtained first indication, that an interruption, or reduction in power, of transmission of at least a first set of one or more reference signals may have to be performed. For example, upon detecting a failure in one of the functions managed by the second network node 112, e.g., in the DU or in the CU of an gNB, the first network node 111 may determine in this Action 602 to stop the transmissions, e.g., SSB or CSI-RS, used by at least one of the one or more devices 130 for performing the mobility measurements that may eventually trigger CHO.

[0120] Determining may be understood as calculating, estimating, deriving or similar. The AI / ML platform run by the first network node 111 mentioned earlier, may host the logic used for detecting failures and for determining which ones may merit forcing CHO to different devices and which ones may not, e.g., because they may be solved by other means.

[0121] In some embodiments, the reduction in power of transmission may be below a threshold.

[0122] In some embodiments, the first network node 111 may determine that responsive to the obtaining in Action 601 of the first indication, interruption or reduction in power of transmission, by the second network node 112 or the third network node 113 operating in the wireless communications network 100, of at least the first set of one or more reference signals may have to be performed.

[0123] In some embodiments, the first network node 111 may determine that the interruption, or reduction in power, of transmission may have to be performed of all the one or more reference signals.

[0124] In other embodiments, the first network node 111 may determine that the interruption, or reduction in power, of transmission of at least the first set of one or more reference signals may have to be performed, and not of all of the one or more reference signals that may be used to trigger conditional handover of the one or more devices 130 because in some examples, the first network node 111 may wish to ensure that the one or mode devices 130 may be forced to trigger CHO in a gradual manner. The gradual behaviour produced by these embodiments may be understood to reduce the potential collisions, e.g., during random access, that may take place if many devices may trigger CHO at the same time. The first network node 111 may determine to perform the gradual interruption, or reduction in power, of transmission of the one or more reference signals, e.g., as follows.

[0125] In a first way of implementation, the first network node 111 may determine to perform the interruption, or reduction in power of transmission in different groups of signals and / or devices. The NW, e.g., the first network node 111, may have configured the first set of devices 131 , e.g., a first group of UEs, to perform CHO-related measurements in a first set of transmissions, that is, the first set of one or more reference signals. Accordingly, in some embodiments, as stated earlier, the first set of one or more reference signals may have to be measured by at least the one first set of devices 131 of the one or more devices 130 served by the second network node 112 or the third network node 113. The NW, e.g., the first network node 111, may have configured the second set of devices 132, e.g., a second group of UEs, to perform CHO-related measurements in a second set of transmissions, that is, a second set of one or more reference signals. According to the foregoing, in some embodiments, as mentioned earlier, the second set of one or more reference may be signals to be measured by at least the one second set of devices 132 of the one or more devices 130 served by the second network node 112 or the third network node 113. Upon determining that the CHO may have to be triggered, e.g., due to node failure, the first network node 111 may first determine to act on, e.g., stop, the first set of one or more reference signals, forcing the first set of devices 131 to trigger CHO. This may be followed, e.g., after a certain interval, by acting on, e.g., stopping, the second set of one or more reference signals, forcing the second set of devices 132 to trigger CHO.

[0126] According to the foregoing, in some embodiments, one of the following options may apply. According to a first option, the determining in this Action 602 may comprise that, based on the obtained first indication, the first network node 111 may determine that the interruption, or reduction in power, of transmission of at least the second set of one or more reference signals also may have to be performed. According to a second option, the determining in this Action 602 may comprise that, based on the obtained first indication, the first network node 111 may determine that transmission of at least the second set of one or more reference signals may have to be performed.

[0127] Another example may comprise lowering the power of the DL signals, e.g., the one or more reference signals, in a progressive way, so that the first set of devices 131, e.g., celledge devices, may be likely to trigger CHO earlier than the second set of devices 132, e.g., cell-center UEs.

[0128] To further illustrate the point, two additional examples of such sets of transmissions may be considered. In a first example, the first set of transmissions, e.g., the first set of one or more reference signals, may correspond to transmissions of CSI-RS while the second set of transmissions, e.g., the second set of one or more reference signals, may correspond to transmissions of SSB. In a second example, the first set of transmissions, e.g., the first set of one or more reference signals, may correspond to transmissions of CSI-RS according to a first configuration, e.g., periodicity, while the second set of transmissions, e.g., the second set of one or more reference signals, may correspond to transmissions of CSI-RS according to a second configuration, e.g., periodicity.

[0129] In accordance with the foregoing, in some embodiments, the first set of one or more reference signals may comprise CSI reference signals or synchronization signals.

[0130] The first set of one or more reference signals may have to be measured by at least the one first set of devices 131 of the one or more devices 130 served by the second network node 112 or the third network node 113.

[0131] In some embodiments, at least one of the following may apply: a) the second set of one or more reference signals comprises CSI reference signals or synchronization signals, and b) the first set of one or more reference signals may comprise reference signals having a first configuration, and the second set of one or more reference signals may comprise reference signals having a second configuration.

[0132] In some examples, the configurations described in this embodiment may be associated with a performance target, e.g., a level of reliability, availability, and resilience-performance. For example, devices with more demanding performance targets, e.g., in terms of allowable service interruption time, may be part of the first set of devices 131 whereas devices with more relaxed performance targets may be part of the second set of devices 132. The assignment of devices to a group may be part of or derived from a service-level agreement (SLA).

[0133] Action 603

[0134] In this Action 603, the first network node 111 initiates, responsive to the obtaining in Action 601 of the first indication, the interruption or reduction in power of transmission, by the second network node 112 or the third network node 113 operating in the wireless communications network 100, of at least the first set of one or more reference signals.

[0135] The second indication may trigger conditional handover of at least the first set of devices 131. That is, the NW, through the first network node 111 , may force at least the first set of devices 131 to trigger CHO.

[0136] Initiating may be understood as starting itself, e.g., in embodiments wherein the first network node 111 may be the same node as the third network node 112 or the third network node 113, or triggering, enabling, or facilitating another node, e.g., the second network node 112 or the third network node 113 to perform, in this case, the interruption or reduction in power of transmission of at least the first set of one or more reference signals.

[0137] Accordingly, the initiating in this Action 603 of the interruption, or reduction in power, of transmission may comprise one of: a) interrupting, or reducing in power, the transmission, and b) sending a second indication to the second network node 112 or the third network node 113. The second indication may indicate that transmission is to be interrupted or reduced in power. As mentioned earlier, in some embodiments, at least two of the first network node 111, the second network node 112 and the third network node 113 may be the same network node. In some examples, the first network node 111 may be a base station, e.g., a gNB, and may may apply the interruption or reduction in power of transmission itself.

[0138] In some examples of the embodiments wherein the first network node 111 may be the same or may be co-localized with the third network node 113, the first network node 111 may manage a function that may implement both failure detection in Action 601 and transmission signals control in this Action 603. This is the case where a function, e.g., a DU, may actively monitor the status of other functions, e.g., a CU-UP, for example, by use of a control loop.

[0139] In some examples, each of the first network node 111, the second network node 112, and in embodiments comprising the another network node, the another node, may be different nodes. In one example, two different gNB functions may be involved.

[0140] In some examples of the embodiments wherein the first network node 111 may be different from the second network node 112, and the first network node 111 may be the same as the third network node 113, the second network node 112, may manage a function that may have failed or that may be likely to fail, and in Action 601 may signal its condition to another function managed by the first network node 111 , which in turn may, in this Action 603, adapt its signals transmission with the goal of triggering CHO.

[0141] In some examples, the second network node 112, or the another network node, may manage a first function that may detect the failure, e.g., of its own, in the case of the second network node 112 being the detector node, or of a third function, in the case of the another network node being the detector node, and may, according to Action 601, notify this to the first network node 111 , which may manage a second gNB function. In response, the first network node 111 may, via the second gNB function, according to this Action 603, act on the transmissions that may be relevant for triggering CHO. Alternatively, the second network node 112 or the another network node, via gNB function 1 , may command the first network node 111 , via gNB function 2, to act, without specifying that this is due to a failure.

[0142] In other examples, each of the first network node 111 and the third network node 113 may be different nodes. In one such example, two different gNB functions may be involved. The first network node 111 may manage the first function that may, according to Action 601 , detect the failure, e.g., of its own or of a third function, that is, the second network node 112, and may, according to this Action 603, notify this to the third network node 113, which may manage the second gNB function. In response, the third network node 113 may, via the second gNB function, act on the transmissions that may be relevant for triggering CHO. Alternatively, the first network node 111 , via gNB function 1 , may command the third network node 113, via gNB function 2, to act, without specifying that this is due to a failure. In some examples, the first network node 111 may be a different network node as the third network node 113. In some of such examples, the first network node 111 may manage the gNB function 1, which may correspond to a DU that may, according to this Action 603, stop providing the third network node 113, managing an RU, gNB function 2, the necessary input for sending the corresponding signals. Consequently, the RU may stop transmitting said signals.

[0143] In some examples, the first network node 111 may be the same network node as the third network node 113, and they may be different from the second network node 112 or the another node. In some of such examples, the second network node 112, or the another node, may manage the gNB function 1 , which may correspond to a DU that may, in Action 601, request the first network node 111 , that may manage a RU, gNB function 2, to stop sending the corresponding signals e.g., SSB or CSI-RS.

[0144] In some examples, three different gNB functions are involved. The second network node 112, or the another network node, may manage a first function, which may detect the failure, e.g., of its own, in the case of the second network node 112, or of a third function, in the case of the another network node, and, according to Action 601 , notify this to the first network node 111 , which may manage a second gNB function. In response, the first network node 111 , via the second gNB function, may determine, according to Action 602, that it may be necessary to trigger a procedure for handling the failure, e.g., forcing CHO for at least the first set of devices 131 , for example, to reduce the service interruption time. To this end, the second gNB function may, according to this Action 603, command the third network node 113 managing the gNB function 3 to act.

[0145] In some examples, the second network node 112 may manage a CU-UP and, in Action 601 , may indicate the failure to the first network node 111, which may manage a DU, and in response, the DU may, by sending the second indication in this Action 603, request the third network node 113, which may manage a third function, e.g., gNB function 3, such as an RU, to stop sending the corresponding signals, e.g., SSB or CSI-RS.

[0146] The initiating in this Action 603 of the interruption, or reduction in power, may be responsive to the determination in Action 602.

[0147] According to the foregoing, in some embodiments, as mentioned earlier, the second set of one or more reference may be signals to be measured by at least the one second set of devices 132 of the one or more devices 130 served by the second network node 112 or the third network node 113. In such embodiments, one of the following options may apply. According to a first option, the determining in Action 602 may comprise that, based on the obtained first indication, the first network node 111 may determine that the interruption, or reduction in power, of transmission of at least the second set of one or more reference signals also may have to be performed, and the initiating in this Action 603 of the interruption, or reduction in power, may be responsive to the determination in Action 602. According to a second option, the determining in this Action 602 may comprise that, based on the obtained first indication, the first network node 111 may determine that transmission of at least the second set of one or more reference signals may have to be performed.

[0148] In some examples, the action on the transmissions that may be relevant for triggering CHO may be part of a sequence of actions for restarting or shutting down a function. For example, the first network node 111 may be the same network node as the second network node 112, e.g., a DU or CU, that may be forced to restart or shut down, and may send the second indication as a request to stop the corresponding transmissions.

[0149] In some embodiments, the interruption, or reduction in power, of transmission may be performed by depowering one or more beamforming beams. One practical way to implement embodiments herein may be by gradually depowering an increasing number of beams in the serving cell, so that not all the one or more devices 130, e.g., UEs, in the cell may trigger CHO simultaneously.

[0150] That the reduction in power of transmission may have to be below the threshold may be indicated to the second network node 112 or the third network node 113.

[0151] It may be noted that embodiments herein may not involve any additional signalling to or configuration of the one or more devices 130 beyond the CHO configuration.

[0152] ORAN is currently discussing a standardized lower layer split (LLS) between the RU and the baseband (BB) unit (e.g., the DU). In some examples of embodiments herein, signalling from this standardized LLS may be used to act on the signals.

[0153] Embodiments of a method, performed by the second network node 112, will now be described with reference to the flowchart depicted in Figure 7. The method is for handling the failure. The second network node 112 operates in the wireless communications network 100. The method may be understood to be computer-implemented.

[0154] Several embodiments are comprised herein. In some embodiments all the actions may be performed. In some embodiments, one of the actions may be optional. It should be noted that the examples herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 , and will thus not be repeated here. For example, the first network node 111 may manage a DU, the second network node 112 may manage a CU, e.g., a CU- UP, and the third network node 113 may manage an RU. Action 701

[0155] In this Action 701 , the second network node 112 detects the occurrence of the failure, in the second network node 112 or in the interface of the second network node 112.

[0156] Action 702

[0157] In this Action 702, the second network node 112 sends the first indication indicating the occurrence of the failure in the second network node 112 to the first network node 111 operating in the wireless communications network 100.

[0158] Action 703

[0159] In this Action 703, the second network node 112 receives the second indication from the first network node 111. The second indication indicates that transmission by the second network node 112 or the third network node 113 operating in the wireless communications network 100, of at least the first set of one or more reference signals is to be interrupted, or reduced in power.

[0160] In some embodiments, the second indication may further indicate that transmission of at least the second set of one or more reference signals to be measured by at least the one second set of devices 132 of one or more devices 130, served by the second network node 112 or the third network node 113, may have to be also interrupted, or reduced in power.

[0161] In some embodiments, at least one of the following may apply: a) the second set of one or more reference signals may comprise CSI-RS or synchronization signals, and b) the first set of one or more reference signals may comprise the reference signals having the first configuration, and the second set of one or more reference signals may comprise reference signals having the second configuration.

[0162] Action 704

[0163] In this Action 704, the second network node 112 may initiate, responsive to the received second indication, interruption or reduction in power of transmission, by the second network node 112 or the third network node 113, of at least the first set of one or more reference signals to be measured by at least one first set of devices 131 of one or more devices 130 served by the second network node 112.

[0164] In some embodiments, the initiating in this Action 704 of the interruption, or reduction in power, of transmission may comprise one of: a) interrupting, or reducing in power, the transmission, and b) sending a third indication to the third network node 113. The third indication may indicate that transmission is to be interrupted, or reduced in power. In some embodiments, at least one of the following may apply: a) the detecting in Action 701 may comprise detecting that the failure has happened, is happening or is to happen within a time period, b) the first indication may indicate that the failure has happened, is happening or is to happen within the time period, c) the failure may be of one or more functions managed by the second network node 112, d) the first set of one or more reference signals may comprise CSI reference signals or synchronization signals, e) the first set of one or more reference signals may be to be measured by at least the one first set of devices 131 of the one or more devices 130 served by the second network node 112 or the third network node 113, f) the transmission may have to be reduced in power below the threshold, g) the second indication may indicate that the transmission is to be reduced in power below the threshold, h) the reduction in power of transmission may be initiated by the second network node 112 or the third network node 113 below the threshold, i) the interruption, or reduction in power, of transmission may be performed by depowering the one or more beamforming beams, j) the one or more reference signals may be used to trigger conditional handover of the one or more devices 130, k) the second indication may trigger conditional handover of at least the first set of devices 131 , and I) at least two of the first network node 111 , the second network node 112 and the third network node 113 may the same network node.

[0165] Embodiments of a method, performed by the third network node 113, will now be described with reference to the flowchart depicted in Figure 8. The method is for handling the failure. The third network node 113 operates in the wireless communications network 100. The method may be understood to be computer-implemented.

[0166] Several embodiments are comprised herein. In some embodiments all the actions may be performed. In some embodiments, one of the actions may be optional. It should be noted that the examples herein are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 , and will thus not be repeated here. For example, the first network node 111 may manage a DU, the second network node 112 may manage a CU, e.g., a CU- UP, and the third network node 113 may manage an RU.

[0167] Action 801

[0168] In this Action 801 , the third network node 113 receives the second indication from the first network node 111 operating in the wireless communications network 100. The second indication indicates that transmission by the third network node 113, of at least the first set of one or more reference signals is to be interrupted, or reduced in power.

[0169] Action 802

[0170] In this Action 802, the third network node 113 initiates, responsive to the received second indication, the interruption or reduction in power of transmission, by the third network node 113, of at least the first set of one or more reference signals.

[0171] The initiating in this Action 804 of the interruption, or reduction in power, of transmission may comprise executing the interruption, or reduction in power, of the transmission.

[0172] The second indication may further indicate that transmission of at least the second set of one or more reference signals to be measured by at least the one second set of devices 132 of the one or more devices 130, served by the third network node 113, may have to be also interrupted, or reduced in power.

[0173] In some embodiments, at least one of the following may apply: a) the second set of one or more reference signals may comprise CSI-RS or synchronization signals, and b) the first set of one or more reference signals may comprise the reference signals having the first configuration, and the second set of one or more reference signals may comprise reference signals having the second configuration.

[0174] In some embodiments, at least one of the following may apply: a) the first set of one or more reference signals may comprise CSI reference signals or synchronization signals, b) the first set of one or more reference signals may be to be measured by at least the one first set of devices 131 of the one or more devices 130 served by the second network node 112 or the third network node 113, c) the transmission may have to be reduced in power below the threshold, d) the second indication may indicate that the transmission is to be reduced in power below the threshold, e) the reduction in power of transmission may be initiated by the third network node 113 below the threshold, f) the interruption, or reduction in power, of transmission may be performed by depowering the one or more beamforming beams, g) the one or more reference signals may be used to trigger conditional handover of the one or more devices 130, h) the second indication may trigger conditional handover of at least the first set of devices 131 , and i) the first network node 111 and the third network node 113 may the same network node.

[0175] Figure 9 is a flowchart depicting a non-limiting example of a method performed by the first network node 111 , according to embodiments herein. In accordance with Action 601 , upon detecting the failure in one of the functions managed by the second network node 112, e.g., in the DU or in the CU of an gNB, the first network node 111 may determine, in Accordance with Action 602, to stop the transmissions, e.g., SSB or CSI-RS, used by at least the first set of devices 131, for performing the mobility measurements that may eventually trigger CHO.

[0176] Figure 10 is a signalling diagram illustrating a non-limiting example of a method performed by the first network node 111 and the second network node 112, according to embodiments herein. Particularly, Figure 10 depicts an example of embodiments herein involving failure notification signalling between two different gNB functions. In this example, the second network node 112 manages a first function that may, according to Action 701 , detect the failure, e.g., of its own, and, according to Action 702 and Action 601, may notify this to the first network node 111, which may manage a second gNB function. In response, the first network node 111 , via the second gNB function, may, according to Action 603, act on the transmissions that may be relevant for triggering CHO.

[0177] Figure 11 is a signalling diagram illustrating a non-limiting example of a method performed by the first network node 111 and the third network node 113, according to embodiments herein. Particularly, Figure 12 depicts an example of embodiments herein involving signalling requesting an action between two functions. Figure 11 may be understood to be an alternative to Figure 10. The first network node 111 , via gNB function 1 , may, according to Action 601 , detect the failure and, according to Action 603 and Action 801 , may command the third network node 113, via the gNB function 2, to act, without specifying that this is due to a failure. The third network node 113 may then, according to Action 802, act on the transmissions that may be relevant for triggering CHO.

[0178] Figure 12 is a signalling diagram illustrating a non-limiting example of a method performed by the first network node 111 , the second network node 112 and the third network node 113, according to embodiments herein. Particularly, Figure 12 depicts an example of embodiments herein involving three different gNB functions. The second network node 112, may manage a first function that, according to Action 701 , may detect the failure, e.g., of its own, and may, according to Action 702 and Action 601 , notify this to the first network node 111 managing a second gNB function. In response, the first network node 111 , via the second gNB function, may, according to Action 602, determine that it may be necessary to trigger a procedure for handling the failure, e.g., forcing CHO for at least the first set of devices 131 , for example, to reduce the service interruption time. To this end, the first network node 111 , via the second gNB function, may, according to Action 603 and Action 801, command the third network node 113, managing gNB function 3, to act. The third network node 113 may then, according to Action 802, act on the transmissions that may be relevant for triggering CHO. As a summarized overview of the foregoing, embodiments herein may be understood to relate to a method that, upon detecting a failure in a subsystem, e.g., a failure of a node, a function or an interface, may act on the transmissions that may be used by the UEs to perform measurements related to CHO. With this action, the network (NW) may indirectly force the UEs to trigger CHO before triggering an RLF.

[0179] Certain embodiments herein may provide one or more of the following technical advantage(s). Embodiments herein may be understood to enable to reduce the service interruption time by ensuring that the failures in a node may be quickly reflected in the transmissions on which the UE may perform the CHO-related measurements.

[0180] Some embodiments herein may ensure an ordered execution of CHO by multiple UEs, thereby reducing congestion and collision issues, e.g., during random access.

[0181] Figure 13 depicts an example of the arrangement that the first network node 111 may comprise to perform the method described in Figure 6 and / or Figures 8-12. The first network node 111 may be understood to be for handling the failure. The first network node 111 is configured to operate in the wireless communications network 100.

[0182] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 , and will thus not be repeated here. For example, the first network node 111 may be configured to manage a DU, the second network node 112 may be configured to manage a CU, e.g., a CU-UP, and the third network node 113 may be configured to manage an RU.

[0183] The first network node 111 is configured to obtain the first indication configured to indicate occurrence of the failure in the second network node 112 configured to operate in the wireless communications network 100, or in the interface of the second network node 112.

[0184] The first network node 111 is also configured to initiate, responsive to obtaining the first indication, interruption or reduction in power of transmission, by the second network node 112 or the third network node 113 configured to operate in the wireless communications network 100, of at least the first set of one or more reference signals.

[0185] In some embodiments, the obtaining of the first indication may be configured to comprise one of: a) receiving the first indication from the second network node 112 or from another network node configured to operate in the wireless communications network 100, and b) detecting the failure.

[0186] In some embodiments, the initiating of the interruption, or reduction in power, of transmission may be configured to comprise one of: a) interrupting, or reducing in power, the transmission, and b) sending the second indication to the second network node 112 or the third network node 113. The second indication may be further configured to indicate that transmission may have to be interrupted or reduced in power.

[0187] In some embodiments, the first network node 111 may be further configured to determine, based on the first indication configured to be obtained, that the interruption, or reduction in power, of transmission of at least the first set of one or more reference signals may have to be performed, and the initiating of the interruption, or reduction in power, may be configured to be responsive to the determination.

[0188] In some embodiments, the second set of one or more reference may be configured to be signals to be measured by at least the one second set of devices 132 of the one or more devices 130 configured to be served by the second network node 112 or the third network node 113. In such embodiments, one of the following options may apply. According to a first option, the determining may be configured to comprise that, based on the first indication configured to be obtained, the first network node 111 may be configured to determine that the interruption, or reduction in power, of transmission of at least the second set of one or more reference signals also may have to be performed, and the initiating of the interruption, or reduction in power, may be configured to be responsive to the determination. According to a second option, the determining may be configured to comprise that, based on the first indication configured to be obtained, the first network node 111 may be configured to determine that transmission of at least the second set of one or more reference signals may have to be performed

[0189] In some embodiments, at least one of the following may apply: a) the second set of one or more reference signals may be configured to comprise CSI reference signals or synchronization signals, and b) the first set of one or more reference signals may be configured to comprise reference signals having the first configuration, and the second set of one or more reference signals may be configured to comprise reference signals having the second configuration.

[0190] In some embodiments, at least one of the following may apply: a) the first indication may be configured to indicate that the failure has happened, is happening or is to happen within a time period, b) the failure may be configured to be of the one or more functions configured to be managed by the second network node 112, c) the first set of one or more reference signals may be configured to comprise CSI reference signals or synchronization signals, d) the first set of one or more reference signals may be configured to be to be measured by at least the one first set of devices 131 of the one or more devices 130 configured to be served by the second network node 112 or the third network node 113, e) the reduction in power of transmission may be configured to be below the threshold, f) that the reduction in power of transmission is to be below the threshold may be configured to be indicated to the second network node 112 or the third network node 113, g) the interruption, or reduction in power, of transmission is configured to be performed by depowering the one or more beamforming beams, h) the one or more reference signals may be configured to be used to trigger conditional handover of the one or more devices 130, i) the second indication may be configured to trigger conditional handover of at least the first set of devices 131, and j) at least two of the first network node 111 , the second network node 112 and the third network node 113 may be configured to be the same network node.

[0191] The embodiments herein in the first network node 111 may be implemented through one or more processors, such as a processing circuitry 1301 in the first network node 111 depicted in Figure 13, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the first network node 111. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the first network node 111.

[0192] The first network node 111 may further comprise a memory 1302 comprising one or more memory units. The memory 1302 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the first network node 111.

[0193] In some embodiments, the first network node 111 may receive information from, e.g., the second network node 112, the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100, through a receiving port 1303. In some embodiments, the receiving port 1303 may be, for example, connected to one or more antennas in first network node 111. In other embodiments, the first network node 111 may receive information from another structure in the communications network 100 through the receiving port 1303. Since the receiving port 1303 may be in communication with the processing circuitry 1301 , the receiving port 1303 may then send the received information to the processing circuitry 1301. The receiving port 1303 may also be configured to receive other information. The processing circuitry 1301 in the first network node 111 may be further configured to transmit or send information to e.g., the second network node 112, the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100, through a sending port 1304, which may be in communication with the processing circuitry 1301, and the memory 1302.

[0194] Those skilled in the art will also appreciate that the units comprised within the first network node 111 described above as being configured to perform different actions, may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 1301 , perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0195] The first network node 111 may be configured to perform any of the Actions described in relation to Figure 6 and / or Figures 8-12, e.g., by means of the processing circuitry 1301 within the first network node 111, configured to perform any of such actions.

[0196] Also, in some embodiments, different units comprised within the first network node 111 may be configured to perform the different actions described above, implemented as one or more applications running on one or more processors such as the processing circuitry 1301.

[0197] Thus, the methods according to the embodiments described herein for the first network node 111 may be respectively implemented by means of a computer program 1305 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 1301, cause the at least one processing circuitry 1301 to carry out the actions described herein, as performed by the first network node 111. The computer program 1305 product may be stored on a computer-readable storage medium 1306. The computer- readable storage medium 1306, having stored thereon the computer program 1305, may comprise instructions which, when executed on at least one processing circuitry 1301, cause the at least one processing circuitry 1301 to carry out the actions described herein, as performed by the first network node 111. In some embodiments, the computer-readable storage medium 1306 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 1305 product may be stored on a carrier containing the computer program 1305 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1306, as described above. The first network node 111 may comprise a communication interface configured to facilitate, or an interface unit to facilitate, communications between the first network node 111 and other nodes or devices, e.g., the second network node 112, the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

[0198] In other embodiments, the first network node 111 may comprise a radio circuitry 1307, which may comprise e.g., the receiving port 1303 and the sending port 1304.

[0199] The radio circuitry 1307 may be configured to set up and maintain at least a wireless connection with any of the second network node 112, the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0200] Hence, embodiments herein also relate to the first network node 111 operative to operate in the communications network 100. The first network node 111 may comprise the processing circuitry 1301 and the memory 1302, said memory 1302 containing instructions executable by said processing circuitry 1301 , whereby the first network node 111 is further operative to perform the actions described herein in relation to the first network node 111, e.g., in Figure 6 and / or Figures 8-12.

[0201] In Figure 13, optional units are indicated with dashed boxes.

[0202] Figure 14 depicts an example of the arrangement that the second network node 112 may comprise to perform the method described in Figure 7, Figure 10 and / or Figure 12. The second network node 112 may be understood to be for handling the failure. The second network node 112 is configured to operate in the wireless communications network 100.

[0203] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the second network node 112, and will thus not be repeated here. For example, the first network node 111 may be configured to manage a DU, the second network node 112 may be configured to manage a CU, e.g., a CU-UP, and the third network node 113 may be configured to manage an RU. The second network node 112 is configured to detect the occurrence of the failure, in the second network node 112 or in the interface of the second network node 112.

[0204] The second network node 112 is also configured to send the first indication configured to indicate the occurrence of the failure in the second network node 112 to the first network node 111 configured to operate in the wireless communications network 100.

[0205] The second network node 112 is further configured to receive the second indication from the first network node 111. The second indication is configured to indicate that transmission by the second network node 112 or the third network node 113 configured to operate in the wireless communications network 100, of at least the first set of one or more reference signals is to be interrupted, or reduced in power.

[0206] In some embodiments, the second network node 112 may be further configured to initiate, responsive to the second indication configured to be received, interruption or reduction in power of transmission, by the second network node 112 or the third network node 113, of at least the first set of one or more reference signals configured to be to be measured by at least the one first set of devices 131 of the one or more devices 130 configured to be served by the second network node 112.

[0207] In some embodiments, the initiating of the interruption, or reduction in power, of transmission may be configured to comprise one of: a) interrupting, or reducing in power, the transmission, and b) sending the third indication to the third network node 113. The third indication may be configured to indicate that transmission may have to be interrupted or reduced in power.

[0208] In some embodiments, the second indication may be further configured to indicate that transmission of at least the second set of one or more reference signals configured to be measured by at least the one second set of devices 132 of the one or more devices 130, configured to be served by the second network node 112 or the third network node 113, may have to be also interrupted, or reduced in power.

[0209] In some embodiments, at least one of the following may apply: a) the second set of one or more reference signals may be configured to comprise CSI reference signals or synchronization signals, and b) the first set of one or more reference signals may be configured to comprise reference signals configured to have the first configuration, and the second set of one or more reference signals may be configured to comprise reference signals configured to have the second configuration.

[0210] In some embodiments, at least one of the following may apply: a) the detecting may be configured to comprise detecting that the failure has happened, is happening or is to happen within the time period, b) the first indication may be configured to indicate that the failure has happened, is happening or is to happen within the time period, c) the failure may be configured to be of the one or more functions configured to be managed by the second network node 112, d) the first set of one or more reference signals may be configured to comprise CSI reference signals or synchronization signals, e) the first set of one or more reference signals may be configured to be measured by at least the one first set of devices 131 of the one or more devices 130 configured to be served by the second network node 112 or the third network node 113, f) the transmission may be configured to be reduced in power below the threshold, g) the second indication may be configured to indicate that the transmission may have to be reduced in power below the threshold, h) the reduction in power of transmission may be configured to be initiated by the second network node 112 or the third network node 113 below the threshold, i) the interruption, or reduction in power, of transmission may be configured to be performed by depowering the one or more beamforming beams, j) the one or more reference signals may be configured to be used to trigger conditional handover of the one or more devices 130, k) the second indication may be configured to trigger conditional handover of at least the first set of devices 131 , and I) at least two of the first network node 111 , the second network node 112 and the third network node 113 may be configured to be the same network node.

[0211] The embodiments herein in the second network node 112 may be implemented through one or more processors, such as a processing circuitry 1401 in the second network node 112 depicted in Figure 14, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the second network node 112. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the second network node 112.

[0212] The second network node 112 may further comprise a memory 1402 comprising one or more memory units. The memory 1402 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the second network node 112.

[0213] In some embodiments, the second network node 112 may receive information from, e.g., the first network node 111 , the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100, through a receiving port 1403. In some embodiments, the receiving port 1403 may be, for example, connected to one or more antennas in second network node 112. In other embodiments, the second network node 112 may receive information from another structure in the communications network 100 through the receiving port 1403. Since the receiving port 1403 may be in communication with the processing circuitry 1401, the receiving port 1403 may then send the received information to the processing circuitry 1401. The receiving port 1403 may also be configured to receive other information.

[0214] The processing circuitry 1401 in the second network node 112 may be further configured to transmit or send information to e.g., the first network node 111, the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100, through a sending port 1404, which may be in communication with the processing circuitry 1401, and the memory 1402.

[0215] Those skilled in the art will also appreciate that the units comprised within the second network node 112 described above as being configured to perform different actions, may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 1401 , perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0216] The second network node 112 may be configured to perform any of the Actions described in relation to Figure 7, Figure 10 and / or Figure 12, e.g., by means of the processing circuitry 1401 within the second network node 112, configured to perform any of such actions.

[0217] Also, in some embodiments, different units comprised within the second network node 112 may be configured to perform the different actions described above, implemented as one or more applications running on one or more processors such as the processing circuitry 1401.

[0218] Thus, the methods according to the embodiments described herein for the second network node 112 may be respectively implemented by means of a computer program 1405 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 1401, cause the at least one processing circuitry 1401 to carry out the actions described herein, as performed by the second network node 112. The computer program 1405 product may be stored on a computer-readable storage medium 1406. The computer-readable storage medium 1406, having stored thereon the computer program 1405, may comprise instructions which, when executed on at least one processing circuitry 1401, cause the at least one processing circuitry 1401 to carry out the actions described herein, as performed by the second network node 112. In some embodiments, the computer-readable storage medium 1406 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 1405 product may be stored on a carrier containing the computer program 1405 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1406, as described above.

[0219] The second network node 112 may comprise a communication interface configured to facilitate, or an interface unit to facilitate, communications between the second network node

[0220] 112 and other nodes or devices, e.g., the first network node 111, the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

[0221] In other embodiments, the second network node 112 may comprise a radio circuitry 1407, which may comprise e.g., the receiving port 1403 and the sending port 1404.

[0222] The radio circuitry 1407 may be configured to set up and maintain at least a wireless connection with the first network node 111 , the third network node 113, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0223] Hence, embodiments herein also relate to the second network node 112 operative to operate in the communications network 100. The second network node 112 may comprise the processing circuitry 1401 and the memory 1402, said memory 1402 containing instructions executable by said processing circuitry 1401 , whereby the second network node 112 is further operative to perform the actions described herein in relation to the second network node 112, e.g., in Figure 7, Figure 10 and / or Figure 12.

[0224] In Figure 14, optional units are indicated with dashed boxes.

[0225] Figure 15 depicts an example of the arrangement that the third network node 113 may comprise to perform the method described in Figure 8, Figure 11 and / or Figure 12. The third network node 113 may be understood to be for handling the failure. The third network node

[0226] 113 is configured to operate in the wireless communications network 100.

[0227] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 , and will thus not be repeated here. For example, the first network node 111 may be configured to manage a DU, the second network node 112 may be configured to manage a CU, e.g., a CU-UP, and the third network node 113 may be configured to manage an RU.

[0228] The third network node 113 is configured to receive the second indication from the first network node 111 configured to operate in the wireless communications network 100. The second indication is configured to indicate that transmission by the third network node 113 of at least the first set of one or more reference signals is to be interrupted, or reduced in power.

[0229] The third network node 113 is also configured to initiate, responsive to the second indication configured to be received, interruption or reduction in power of transmission, by the third network node 113, of at least the first set of one or more reference signals.

[0230] The initiating of the interruption, or reduction in power, of transmission may be configured to comprise executing the interruption, or reduction in power, of the transmission.

[0231] In some embodiments, the second indication may be further configured to indicate that transmission of at least the second set of one or more reference signals configured to be measured by at least the one second set of devices 132 of the one or more devices 130, configured to be served by the second network node 112 or the third network node 113, may have to be also interrupted, or reduced in power.

[0232] In some embodiments, at least one of the following may apply: a) the second set of one or more reference signals may be configured to comprise CSI reference signals or synchronization signals, and b) the first set of one or more reference signals may be configured to comprise reference signals configured to have the first configuration, and the second set of one or more reference signals may be configured to comprise reference signals configured to have the second configuration.

[0233] In some embodiments, at least one of the following may apply: a) the first set of one or more reference signals may be configured to comprise CSI reference signals or synchronization signals, b) the first set of one or more reference signals may be configured to be measured by at least the one first set of devices 131 of the one or more devices 130 configured to be served by the third network node 113, c) the transmission may be configured to be reduced in power below the threshold, d) the second indication may be configured to indicate that the transmission may have to be reduced in power below the threshold, e) the reduction in power of transmission may be configured to be initiated by the third network node 113 below the threshold, f) the interruption, or reduction in power, of transmission may be configured to be performed by depowering the one or more beamforming beams, g) the one or more reference signals may be configured to be used to trigger conditional handover of the one or more devices 130, h) the second indication may be configured to trigger conditional handover of at least the first set of devices 131 , and i) the first network node 111 and the third network node 113 may be configured to be the same network node. The embodiments herein in the third network node 113 may be implemented through one or more processors, such as a processing circuitry 1501 in the third network node 113 depicted in Figure 15, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the third network node 113. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the third network node 113.

[0234] The third network node 113 may further comprise a memory 1502 comprising one or more memory units. The memory 1502 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the third network node 113.

[0235] In some embodiments, the third network node 113 may receive information from, e.g., the first network node 111 , the second network node 112, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100, through a receiving port 1503. In some embodiments, the receiving port 1503 may be, for example, connected to one or more antennas in third network node 113. In other embodiments, the third network node 113 may receive information from another structure in the communications network 100 through the receiving port 1503. Since the receiving port 1503 may be in communication with the processing circuitry 1501 , the receiving port 1503 may then send the received information to the processing circuitry 1501. The receiving port 1503 may also be configured to receive other information.

[0236] The processing circuitry 1501 in the third network node 113 may be further configured to transmit or send information to e.g., the first network node 111, the second network node 112, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100, through a sending port 1504, which may be in communication with the processing circuitry 1501, and the memory 1502.

[0237] Those skilled in the art will also appreciate that the units comprised within the third network node 113 described above as being configured to perform different actions, may refer to a combination of analog and digital circuits, and / or one or more processors configured with software and / or firmware, e.g., stored in memory, that, when executed by the one or more processors such as the processing circuitry 1501, perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0238] The third network node 113 may be configured to perform any of the Actions described in relation to Figure 8, Figure 11 and / or Figure 12, e.g., by means of the processing circuitry 1501 within the third network node 113, configured to perform any of such actions.

[0239] Also, in some embodiments, different units comprised within the third network node 113 may be configured to perform the different actions described above, implemented as one or more applications running on one or more processors such as the processing circuitry 1501.

[0240] Thus, the methods according to the embodiments described herein for the third network node 113 may be respectively implemented by means of a computer program 1505 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 1501 , cause the at least one processing circuitry 1501 to carry out the actions described herein, as performed by the third network node 113. The computer program 1505 product may be stored on a computer-readable storage medium 1506. The computer- readable storage medium 1506, having stored thereon the computer program 1505, may comprise instructions which, when executed on at least one processing circuitry 1501, cause the at least one processing circuitry 1501 to carry out the actions described herein, as performed by the third network node 113. In some embodiments, the computer-readable storage medium 1506 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 1505 product may be stored on a carrier containing the computer program 1505 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1506, as described above.

[0241] The third network node 113 may comprise a communication interface configured to facilitate, or an interface unit to facilitate, communications between the third network node 113 and other nodes or devices, e.g., the first network node 111 , the second network node 112, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100. The interface may, for example, include a transceiver configured to transmit and receive radio signals over an air interface in accordance with a suitable standard.

[0242] In other embodiments, the third network node 113 may comprise a radio circuitry 1507, which may comprise e.g., the receiving port 1503 and the sending port 1504.

[0243] The radio circuitry 1507 may be configured to set up and maintain at least a wireless connection with the first network node 111 , the second network node 112, the another network node, any of the one or more devices 130, e.g., the set of devices 131 and / or the second set of devices 132, and / or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0244] Hence, embodiments herein also relate to the third network node 113 operative to operate in the communications network 100. The third network node 113 may comprise the processing circuitry 1501 and the memory 1502, said memory 1502 containing instructions executable by said processing circuitry 1501 , whereby the third network node 113 is further operative to perform the actions described herein in relation to the third network node 113, e.g., in Figure 8, Figure 11 and / or Figure 12.

[0245] In Figure 15, optional units are indicated with dashed boxes.

[0246] When using the word "comprise" or “comprising”, it shall be interpreted as non- limiting, i.e. , meaning "consist at least of".

[0247] The embodiments herein are not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention.

[0248] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0249] As used herein, the expression “at least one of:” followed by a list of alternatives separated by commas, and wherein the last alternative is preceded by the “and” term, may be understood to mean that only one of the list of alternatives may apply, more than one of the list of alternatives may apply or all of the list of alternatives may apply. This expression may be understood to be equivalent to the expression “at least one of:” followed by a list of alternatives separated by commas, and wherein the last alternative is preceded by the “or” term.

[0250] Any of the terms processor and circuitry may be understood herein as a hardware component. As used herein, the expression “in some embodiments” has been used to indicate that the features of the embodiment described may be combined with any other embodiment or example disclosed herein.

[0251] As used herein, the expression “in some examples” has been used to indicate that the features of the example described may be combined with any other embodiment or example disclosed herein.

[0252] REFERENCES

[0253] 1. 3GPP TS 38.300, version 17.5.0, 30th June 2023.

Claims

CLAIMS:

1. A method performed by a first network node (111), the method being for handling a failure, the first network node (111) operating in a wireless communications network (100), the method comprising:- obtaining (601) a first indication indicating occurrence of a failure in a second network node (112) operating in the wireless communications network (100), or in an interface of the second network node (112), and- initiating (603), responsive to obtaining (601) the first indication, interruption or reduction in power of transmission, by the second network node (112) or a third network node (113) operating in the wireless communications network (100), of at least a first set of one or more reference signals.

2. The method according to claim 1, wherein the obtaining (601) of the first indication comprises one of:- receiving the first indication from the second network node (112) or from another network node operating in the wireless communications network (100), and- detecting the failure.

3. The method according to any of claims 1-2, wherein the initiating (603) of the interruption, or reduction in power, of transmission comprises one of:- interrupting, or reducing in power, the transmission, and- sending a second indication to the second network node (112) or the third network node (113), the second indication indicating that transmission is to be interrupted or reduced in power.

4. The method according to any of claims 1-3, further comprising:- determining (602), based on the obtained first indication, that the interruption, or reduction in power, of transmission of at least the first set of one or more reference signals has to be performed, and wherein the initiating (603) of the interruption, or reduction in power, is responsive to the determination (602).

5. The method according to claim 4, wherein a second set of one or more reference are signals to be measured by at least one second set of devices (132) of one or moredevices (130) served by the second network node (112) or the third network node (113), and wherein one of:- the determining (602) comprises that, based on the obtained first indication, the first network node (111) determines that the interruption, or reduction in power, of transmission of at least the second set of one or more reference signals also has to be performed, and wherein the initiating (603) of the interruption, or reduction in power, is responsive to the determination (602), and- the determining (602) comprises that, based on the obtained first indication, the first network node (111) determines that transmission of at least the second set of one or more reference signals has to be performed.

6. The method according to 5, wherein at least one of:- the second set of one or more reference signals comprises Channel State Information, CSI, reference signals or synchronization signals, and- the first set of one or more reference signals comprises reference signals having a first configuration, and the second set of one or more reference signals comprises reference signals having a second configuration.

7. The method according to any of claims claim 1-6, wherein at least one of:- the first indication indicates that the failure has happened, is happening or is to happen within a time period,- the failure is of one or more functions managed by the second network node (112),- the first set of one or more reference signals comprises CSI reference signals or synchronization signals,- the first set of one or more reference signals are to be measured by at least one first set of devices (131) of one or more devices (130) served by the second network node (112) or the third network node (113),- the reduction in power of transmission is below a threshold,- that the reduction in power of transmission is to be below the threshold is indicated to the second network node (112) or a third network node (113),- the interruption, or reduction in power, of transmission is performed by depowering one or more beamforming beams,- the one or more reference signals are used to trigger conditional handover of the one or more devices (130),- the second indication triggers conditional handover of at least the first set of devices (131), andat least two of the first network node (111), the second network node (112) and the third network node (113) are the same network node.

8. A method performed by a second network node (112), the method being for handling a failure, the second network node (112) operating in a wireless communications network (100), the method comprising:- detecting (701) occurrence of a failure, in the second network node (112) or in an interface of the second network node (112),- sending (702) a first indication indicating the occurrence of the failure in the second network node (112) to a first network node (111) operating in the wireless communications network (100), and- receiving (703) a second indication from the first network node (111), the second indication indicating that transmission by the second network node(112) or a third network node (113) operating in the wireless communications network (100), of at least a first set of one or more reference signals is to be interrupted, or reduced in power.

9. The method according to claim 8, further comprising:- initiating (704), responsive to the received second indication, interruption or reduction in power of transmission, by the second network node (112) or the third network node (113), of at least the first set of one or more reference signals to be measured by at least one first set of devices (131) of one or more devices (130) served by the second network node (112).

10. The method according to claim 9, wherein the initiating (704) of the interruption, or reduction in power, of transmission comprises one of:- interrupting, or reducing in power, the transmission, and- sending a third indication to the third network node (113), the third indication indicating that transmission is to be interrupted, or reduced in power.

11. The method according to any of claims 8-10, wherein the second indication further indicates that transmission of at least a second set of one or more reference signals to be measured by at least one second set of devices (132) of one or more devices (130), served by the second network node (112) or the third network node (113), has to be also interrupted, or reduced in power.

12. The method according to 11, wherein at least one of:- the second set of one or more reference signals comprises Channel State Information, CSI, reference signals or synchronization signals, and- the first set of one or more reference signals comprises reference signals having a first configuration, and the second set of one or more reference signals comprises reference signals having a second configuration.

13. The method according to any of claims claim 8-12, wherein at least one of:- the detecting (701) comprises detecting that the failure has happened, is happening or is to happen within a time period,- the first indication indicates that the failure has happened, is happening or is to happen within the time period,- the failure is of one or more functions managed by the second network node (112),- the first set of one or more reference signals comprises CSI reference signals or synchronization signals,- the first set of one or more reference signals are to be measured by at least one first set of devices (131) of one or more devices (130) served by the second network node (112) or the third network node (113),- the transmission is to be reduced in power below a threshold,- the second indication indicates that the transmission is to be reduced in power below the threshold,- the reduction in power of transmission is initiated by the second network node (112) or the third network node (113) below the threshold,- the interruption, or reduction in power, of transmission is performed by depowering one or more beamforming beams,- the one or more reference signals are used to trigger conditional handover of the one or more devices (130),- the second indication triggers conditional handover of at least the first set of devices (131), and- at least two of the first network node (111), the second network node (112) and the third network node (113) are the same network node.

14. A method performed by a third network node (113), the method being for handling a failure, the third network node (113) operating in a wireless communications network (100), the method comprising:- receiving (801) a second indication from a first network node (111) operating in the wireless communications network (100), the second indication indicatingthat transmission by the third network node (113) operating in the wireless communications network (100), of at least a first set of one or more reference signals is to be interrupted, or reduced in power, and- initiating (802), responsive to the received second indication, interruption or reduction in power of transmission, by the third network node (113), of at least the first set of one or more reference signals.

15. The method according to claim 14, wherein the initiating (804) of the interruption, or reduction in power, of transmission comprises executing the interruption, or reduction in power, of the transmission.

16. The method according to any of claims 14-15, wherein the second indication further indicates that transmission of at least a second set of one or more reference signals to be measured by at least one second set of devices (132) of the one or more devices (130), served by the third network node (113), has to be also interrupted, or reduced in power.

17. The method according to 16, wherein at least one of:- the second set of one or more reference signals comprises Channel State Information, CSI, reference signals or synchronization signals, and- the first set of one or more reference signals comprises reference signals having a first configuration, and the second set of one or more reference signals comprises reference signals having a second configuration.

18. The method according to any of claims claim 14-17, wherein at least one of:- the first set of one or more reference signals comprises CSI reference signals or synchronization signals,- the first set of one or more reference signals are to be measured by at least one first set of devices (131) of one or more devices (130) served by the third network node (113),- the transmission is to be reduced in power below a threshold,- the second indication indicates that the transmission is to be reduced in power below the threshold,- the reduction in power of transmission is initiated by the third network node (113) below the threshold,- the interruption, or reduction in power, of transmission is performed by depowering one or more beamforming beams,- the one or more reference signals are used to trigger conditional handover of the one or more devices (130),- the second indication triggers conditional handover of at least the first set of devices (131), and- the first network node (111) and the third network node (113) are the same network node.

19. A first network node (111), for handling a failure, the first network node (111) being configured to operate in a wireless communications network (100), the first network node (111) being further configured to:- obtain a first indication configured to indicate occurrence of a failure in a second network node (112) configured to operate in the wireless communications network (100), or in an interface of the second network node (112), and- initiate, responsive to obtaining the first indication, interruption or reduction in power of transmission, by the second network node (112) or a third network node (113) configured to operate in the wireless communications network (100), of at least a first set of one or more reference signals.

20. The first network node (111) according to claim 19, wherein the obtaining of the first indication is configured to comprise one of:- receiving the first indication from the second network node (112) or from another network node configured to operate in the wireless communications network (100), and- detecting the failure.

21. The first network node (111) according to any of claims 19-20, wherein the initiating of the interruption, or reduction in power, of transmission is configured to comprise one of:- interrupting, or reducing in power, the transmission, and- sending a second indication to the second network node (112) or the third network node (113), the second indication being configured to indicate that transmission is to be interrupted or reduced in power.

22. The first network node (111) according to any of claims 19-21, being further configured to : determine, based on the first indication configured to be obtained, that the interruption, or reduction in power, of transmission of at least the first set of one or more reference signals has to be performed, and wherein the initiating of theinterruption, or reduction in power, is configured to be responsive to the determination (602).

23. The first network node (111) according to claim 22, wherein a second set of one or more reference are configured to be signals to be measured by at least one second set of devices (132) of one or more devices (130) configured to be served by the second network node (112) or the third network node (113), and wherein one of:- the determining is configured to comprise that, based on the first indication configured to be obtained, the first network node (111) determines that the interruption, or reduction in power, of transmission of at least the second set of one or more reference signals also has to be performed, and wherein the initiating of the interruption, or reduction in power, is configured to be responsive to the determination (602), and- the determining is configured to comprise that, based on the first indication configured to be obtained, the first network node (111) determines that transmission of at least the second set of one or more reference signals has to be performed.

24. The first network node (111) according to 23, wherein at least one of:- the second set of one or more reference signals is configured to comprise Channel State Information, CSI, reference signals or synchronization signals, and- the first set of one or more reference signals is configured to comprise reference signals having a first configuration, and the second set of one or more reference signals is configured to comprise reference signals having a second configuration.

25. The first network node (111) according to any of claims claim 23-24, wherein at least one of:- the first indication is configured to indicate that the failure has happened, is happening or is to happen within a time period,- the failure is configured to be of one or more functions configured to be managed by the second network node (112),- the first set of one or more reference signals is configured to comprise CSI reference signals or synchronization signals,- the first set of one or more reference signals are configured to be measured by at least one first set of devices (131) of one or more devices (130) configured to be served by the second network node (112) or the third network node (113),- the reduction in power of transmission is configured to be below a threshold,- that the reduction in power of transmission is to be below the threshold is configured to be indicated to the second network node (112) or a third network node (113),- the interruption, or reduction in power, of transmission is configured to be performed by depowering one or more beamforming beams,- the one or more reference signals are configured to be used to trigger conditional handover of the one or more devices (130),- the second indication is configured to trigger conditional handover of at least the first set of devices (131), and- at least two of the first network node (111), the second network node (112) and the third network node (113) are configured to be the same network node.

26. A second network node (112), for handling a failure, the second network node (112) being configured to operate in a wireless communications network (100), the second network node (112) being further configured to :- detect occurrence of a failure, in the second network node (112) or in an interface of the second network node (112),- send a first indication configured to indicate the occurrence of the failure in the second network node (112) to a first network node (111) configured to operate in the wireless communications network (100), and- receive a second indication from the first network node (111), the second indication being configured to indicate that transmission by the second network node (112) or a third network node (113) configured to operate in the wireless communications network (100), of at least a first set of one or more reference signals is to be interrupted, or reduced in power.

27. The second network node (112) according to claim 26, being further configured to :- initiate, responsive to the second indication configured to be received, interruption or reduction in power of transmission, by the second network node (112) or the third network node (113), of at least the first set of one or more reference signals configured to be to be measured by at least one first set of devices (131) of one or more devices (130) configured to be served by the second network node (112).

28. The second network node (112) according to claim 27, wherein the initiating of the interruption, or reduction in power, of transmission is configured to comprise one of:- interrupting, or reducing in power, the transmission, and- sending a third indication to the third network node (113), the third indication being configured to indicate that transmission is to be interrupted, or reduced in power.

29. The second network node (112) according to any of claims 26-28, wherein the second indication is further configured to indicate that transmission of at least a second set of one or more reference signals configured to be measured by at least one second set of devices (132) of one or more devices (130), configured to be served by the second network node (112) or the third network node (113), has to be also interrupted, or reduced in power.

30. The second network node (112) according to 29, wherein at least one of:- the second set of one or more reference signals is configured to comprise Channel State Information, CSI, reference signals or synchronization signals, and- the first set of one or more reference signals is configured to comprise reference signals configured to have a first configuration, and the second set of one or more reference signals is configured to comprise reference signals configured to have a second configuration.

31. The second network node (112) according to any of claims claim 26-30, wherein at least one of:- the detecting is configured to comprise detecting that the failure has happened, is happening or is to happen within a time period,- the first indication is configured to indicate that the failure has happened, is happening or is to happen within the time period,- the failure is configured to be of one or more functions configured to be managed by the second network node (112),- the first set of one or more reference signals is configured to comprise CSI reference signals or synchronization signals,- the first set of one or more reference signals are configured to be measured by at least one first set of devices (131) of one or more devices (130) configured to be served by the second network node (112) or the third network node (113),- the transmission is configured to be reduced in power below a threshold,- the second indication is configured to indicate that the transmission is to be reduced in power below the threshold,- the reduction in power of transmission is configured to be initiated by the second network node (112) or the third network node (113) below the threshold,- the interruption, or reduction in power, of transmission is configured to be performed by depowering one or more beamforming beams,- the one or more reference signals are configured to be used to trigger conditional handover of the one or more devices (130),- the second indication is configured to trigger conditional handover of at least the first set of devices (131), and- at least two of the first network node (111), the second network node (112) and the third network node (113) are configured to be the same network node.

32. A third network node (113), for handling a failure, the third network node (113) being configured to operate in a wireless communications network (100), the third network node (113) being further configured to :- receive a second indication from a first network node (111) configured to operate in the wireless communications network (100), the second indication being configured to indicate that transmission by the third network node (113), of at least a first set of one or more reference signals is to be interrupted, or reduced in power, and- initiate, responsive to the second indication configured to be received, interruption or reduction in power of transmission, by the third network node (113), of at least the first set of one or more reference signals.

33. The third network node (113) according to claim 32, wherein the initiating of the interruption, or reduction in power, of transmission is configured to comprise executing the interruption, or reduction in power, of the transmission.

34. The third network node (113) according to any of claims 32-33, wherein the second indication is configured to further indicate that transmission of at least a second set of one or more reference signals configured to be measured by at least one second set of devices (132) of the one or more devices (130), configured to be served by the third network node (113), has to be also interrupted, or reduced in power.

35. The third network node (113) according to 34, wherein at least one of:- the second set of one or more reference signals is configured to comprise Channel State Information, CSI, reference signals or synchronization signals, and- the first set of one or more reference signals is configured to comprise reference signals configured to have a first configuration, and the second set of one or more reference signals is configured to comprise reference signals configured to have a second configuration.

36. The third network node (113) according to any of claims claim 32-35, wherein at least one of:- the first set of one or more reference signals is configured to comprise CSI reference signals or synchronization signals,- the first set of one or more reference signals are configured to be measured by at least one first set of devices (131) of one or more devices (130) configured to be served by the third network node (113),- the transmission is configured to be reduced in power below a threshold,- the second indication is configured to indicate that the transmission is to be reduced in power below the threshold,- the reduction in power of transmission is configured to be initiated by the third network node (113) below the threshold,- the interruption, or reduction in power, of transmission is configured to be performed by depowering one or more beamforming beams,- the one or more reference signals are configured to be used to trigger conditional handover of the one or more devices (130),- the second indication is configured to trigger conditional handover of at least the first set of devices (131), and- the first network node (111) and the third network node (113) are configured to be the same network node.

37. A computer program (1305), comprising instructions which, when executed on at least one processing circuitry (1301), cause the at least one processing circuitry (1301) to carry out the method according to any of claims 1-7.

38. A computer-readable storage medium (1306), having stored thereon a computer program (1305), comprising instructions which, when executed on at least one processing circuitry (1301), cause the at least one processing circuitry (1301) to carry out the method according to any of claims 1-7.

39. A computer program (1405), comprising instructions which, when executed on at least one processing circuitry (1401), cause the at least one processing circuitry (1401) to carry out the method according to any of claims 8-13.

40. A computer-readable storage medium (1406), having stored thereon a computer program (1405), comprising instructions which, when executed on at least one processing circuitry (1401), cause the at least one processing circuitry (1401) to carry out the method according to any of claims 8-13.

41. A computer program (1505), comprising instructions which, when executed on at least one processing circuitry (1501), cause the at least one processing circuitry (1501) to carry out the method according to any of claims 14-18.

42. A computer-readable storage medium (1506), having stored thereon a computer program (1505), comprising instructions which, when executed on at least one processing circuitry (1501), cause the at least one processing circuitry (1501) to carry out the method according to any of claims 14-18.

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