First node, wireless device, third node and methods performed thereby, for handling an unavailability of a first protocol layer

Abstract

A computer-implemented method performed by a first node (111). The method is for handling an unavailability of a first protocol layer. The first node (111) operates in a wireless communications network (100). The first node (111) sends (605) an indication to a wireless device (130) operating in the wireless communications network (100). The indication indicates to perform a reconfiguration. The indication is sent using signalling from a different layer than the first protocol layer between a second node (112) and the wireless device (130), wherein the unavailability has been detected.

Description

[0001] FIRST NODE, WIRELESS DEVICE, THIRD NODE AND METHODS PERFORMED THEREBY,

[0002] FOR HANDLING AN UNAVAILABILITY OF A FIRST PROTOCOL LAYER

[0003] TECHNICAL FIELD

[0004] The present disclosure relates generally to a first node and methods performed thereby for handling an unavailability of a first protocol layer. The present disclosure also relates generally to a wireless device, and methods performed thereby for handling the unavailability of the first protocol layer. The present disclosure further relates generally to a third node, and methods performed thereby for handling the unavailability of the first protocol layer.

[0005] BACKGROUND

[0006] 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.

[0007] 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, 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 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 may be understood to be the geographical area where radio coverage is 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 terminals within range of the base stations. The wireless communications network may also be a non-cellular system, comprising 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.

[0008] The standardization organization 3GPP has standardized parts of and continues to specify a New Radio Interface called NR or 5G-UTRA, as well as a Fifth Generation (5G) Packet Core Network (CN), 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 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.

[0009] Handover

[0010] Handover (HO) may be understood to be a mobility procedure used in cellular communications, e.g., in 3GPP NR networks, by which the base station, e.g., a gNB, serving a UE may change. The basic procedure of handover may be understood to have the gNB in control of the entire process. It may typically involve the following steps. The UE may report measurements of signals according to a configuration provided by the network (NW), e.g., the gNB. The NW, e.g., the current serving gNB, may determine whether handover to a target gNB that is, a new serving gNB, may be desirable, e.g., based on the reported measurements.

[0011] The NW may provide the UE a configuration to be used for communication with the target gNB. The UE may detach from the source gNB and synchronize and attach to the target gNB.

[0012] In this basic procedure, legacy Layer 3 (L3) HO, the gNB may be in control of all aspects of the handover.

[0013] Conditional Handover

[0014] Conditional Handover (CHO) may be understood as a mobility procedure for handover introduced by 3GPP in Rel-16 in 3GPP, of which some aspects are depicted in Figure 1 and Figure 2.

[0015] Figure 1 is a signalling diagram depicting basic operations and signalling in conditional handover. The key principles of CHO may be understood to be as follows. CHO may be understood to comprise 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 an execution phase, in which the UE may stop communicating with the source cell and may start communicating with the target cell. The preparation phase and the execution phase of the HO may be understood to be decoupled. In CHO, the preparation phase may take place long before the execution. In the preparation phase, an HO command may be sent in a stable radio condition. During the preparation phase, the UE may be informed of the candidate cells to perform CHO and may be also given a condition or conditions when the UE may have to execute the handover. As depicted in Figure 1 , during the preparation phase, a source node 1 may send a CHO request to a potential target node 2. The potential target node 2 may send in return a CHO request acknowledgment (ACK) comprising an RRCReconfiguration. The source node 1 may then send a CHO configuration to a UE 3, indicating a condition for the HO, e.g., A3 / A5 event + RRCReconfiguration.

[0016] Figure 1 also illustrates another of the key principles of CHO, according to which the actual execution of the HO may be triggered by the UE 3. During the execution phase, the UE 3 may be enabled to start the handover immediately, without network delay. It may be understood to be the UE 3 that may monitor the CHO condition for the target cell(s) candidates and determine, based on measurements and thresholds associated with the configured conditions, that CHO may have to be executed. CHO may be only executed if certain conditions are met. Otherwise, CHO may not be executed. If the CHO is executed, the UE 3 may send a CHO confirmation to the potential target node 2, which may then perform a path switch and UE context release.

[0017] 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 degrade.

[0018] Figure 2 is a signalling diagram from TS 38.300, v. 18.1.0, Clause 9.2.3.4.2 and depicts a more detailed signalling diagram for conditional handover. Prior to a CHO, a UE 20 may exchange user data with a source gNB 21 , which may in turn exchange user data with a User Plane Function (UPF) 22. At 0, mobility control information may be provided by Access and Mobility Management Function (AMF) 23 to the source gNB 21. At 1 , the UE 20 may perform measurement control and send reports to the source gNB 21. At 2, the source gNB 21 may take a CHO decision. At 3, the source gNB 21 may send, based on the CHO decision, an HO request to a target gNB 24, as well as to one or more other potential target gNB(s) 25. At 4, each of the target gNB 24, as well as to one or more other potential target gNB(s) 25 may perform admission control. At 5, each of the target gNB 24, as well as to one or more other potential target gNB(s) 25 may send a handover request acknowledge to the source gNB 21. At 6, the source gNB 21 may then send an RRCReconfiguration to the UE 20. At 7, the UE 20 may send an RRCReconfiguration Complete message back to the source gNB 21. Steps 1-7 may be understood to be comprised in the HO preparation phase. In the HO execution phase, the UE 20 may evaluate the CHO conditions. Meanwhile, at 7a, the source gNB 21 may perform an early status transfer to the one or more potential target gNB(s) 25. When the CHO conditions may be met, the UE 20 may detach from the old cell and synchronize to the new cell. Any user data from the UFP 22 arriving at the source gNB 21 may be redirected to the one or more potential target gNB(s) 25. At 8, a CHO handover completion may be performed between the UE 20, the source gNB 21 and the target gNB 24. During the handover completion phase, at 8a, the target gNB 24 may indicate the HO success to the source gNB 21. At 8b, the source gNB 21 may then indicate a Sequence Number (SN) status transfer to the target gNB 24. Any user data from the UFP 22 arriving at the source gNB 21 may be redirected to the one or more potential target gNB(s) 25. At 8c, the source gNB 21 may signal an HO cancel to the target gNB 24 and the one or more other potential target gNB(s) 25, if any, to cancel CHO for the UE. The next steps 9-12 may be performed according to Figure 9.2.3.2.1-1 in TS 38.300, v. 18.1.0.

[0019] The following two events, jointly or separately, may be configured as triggers for CHO: Event A3, according to which the neighbour cell may become better than the current serving cell by an offset, and 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.

[0020] 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 need 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) signals that may be part of a synchronization signals block (SSB), which may sometimes be referred to as the Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block, and b) Channel state information reference signals (CSI-RS).

[0021] There may be understood to be differences between SSB and CSI-RS with regards to structure, periodicity, how they are 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.

[0022] When the UE is 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 understood to be locked until the CHO may be performed, and it may impact the node capacity, as more processing may be needed during the time the CFRA preamble may be active / used. Therefore, the use of CFRA, that is, of a CFRA preamble, may be configured only to the limited number of UE belonging to the specific UE group requiring lower interruption.

[0023] Layer 1 (L1) / Layer 2 (L2)-triqqered mobility L1 / L2-Triggered Mobility (LTM) may be understood to be a set of procedures for mobility in which L1 / L2 control signalling may be used for triggering the mobility. Similar to CHO, LTM may decouple preparation and execution phases. The preparation phase may be understood to be very similar to CHO. The serving cell may provide the necessary configuration for the UE to change to another cell. The configuration may be provided using Radio Resource Control (RRC) signalling and may be stored by the UE for later use. The execution phase may be triggered by the network by sending an L1 / L2 control message, particularly, a Medium Access Control (MAC) Control Element (CE). This command may be known as the LTM cell switch command. To allow the network to determine the right time for triggering LTM, the UE may perform some measurements and may report them to the network. In addition, LTM may allow for reducing the interruption time caused by HO by means of having the UE synchronize before the actual HO, in DL and / or UL.

[0024] The signalling diagram of LTM, from Figure 9.2.3.5.2-1 of TS 38.300, v. 18.1.0, is provided in Figure 3. As depicted in Figure 3, during an LTM preparation phase, a UE 31 may be in RRC_Connected mode. At 1 , the UE 31 may send a measurement report to a gNB 32. This may trigger an LTM candidate preparation by the gNB 32. At 2, the gNB 32 may then send an RRC reconfiguration to the UE 31 , indicating an LTM candidate configuration. At 3, the UE 31 may send an RRC reconfiguration complete to the gNB 32. In the next phase, an early synchronization phase, at 4a, the UE 31 and the gNB 32 may perform a DL synchronization with LTM candidate cells, and at 4b, the UE 31 and the gNB 32 may perform an UL synchronization with LTM candidate cells. During the next phase, the LTM cell switch execution may be performed. At 5, the UE 31 may send an L1 measurement report to the gNB 32. Based on the received report, the gNB 32 may take an LTM decision. At 6, the gNB 32 may send an LTM cell switch command (MAC CE) to the UE 31. The UE 31 may then detach from the source and apply target configurations. At 7, the UE 31 and the gNB 32 may perform a Radio Access Channel (RACH) procedure. In the next phase, at 8, the UE 31 and the gNB 32 may perform an LTM cell switch completion.

[0025] If the UE synchronizes early to the new cell, it may also be allowed to move to the new cell without performing random access, that is, to perform a RACH-less LTM.

[0026] Table 1 summarizes the different mobility options just described, indicating the configuration and trigger options for different mobility features.

[0027] Table 1

[0028] Delivery of connectivity services with reliability, availability and resilience

[0029] Delivering connectivity services tailored for business or safety critical applications represents a promising opportunity for wireless cellular networks. Such services may be usually characterized by several performance requirements, which may be formalized in a Service Level Agreement (SLA) between a Connectivity Service Provider (CSP) and their customers. It may 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.

[0030] A large amount of work has been laid down during 5G standardization in order to bound 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 be understood to 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.

[0031] There is an increasing understanding that critical applications requirements may need to also be resilient to occasional failures of network subsystems. Failures in this context may be understood to 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.

[0032] Radio Link Failure

[0033] In some circumstances, the link between a UE and the network mail fail and the transmission of traffic may be interrupted. The UE may detect this issue by different means and declare a radio link failure (RLF). RLF may be declared upon different conditions, including, upon detecting physical layer problems, e.g., expiration of the associated timer T310, and upon reaching a maximum number of retransmissions in the Radio Link Control (RLC) layer. In many cases, after declaring RLF, the UE may attempt to re-establish the RRC connection, which is described later in this document. According to selected parts of the radio link failure procedures from TS 38.331 , v. 18.1.0, the UE may consider RLF to be detected for a Master Cell Group (MCG), that is, MCG RLF, upon T310 expiry in a Primary cell (Pcell), or upon indication from the MCG RLC that the maximum number of retransmissions has been reached while a Small Data Transmission (SDT) procedure is not ongoing. The UE may then be required to discard any segments of segmented RRC messages stored, store the RLF information in a VarRLF-Report, and initiate the connection re-establishment procedure.

[0034] Although the conditions for declaring RLF may be understood to be well defined and captured in the specification, e.g., TS 38.331 , v. 18.1.0, the root cause of the RLF may be quite diverse, including: a degradation in the operating conditions, e.g., because the UE may enter an area with bad coverage, a bad radio Radio Resource Management (RRM) by the network, e.g., improper beam management, failure to trigger handover, etc., a failure in the network, e.g., in the gNB or part of it such as a radio unit (RU), distributed unit (DU), or centralized unit (CU).

[0035] In spite of the different root causes, in most situations, the UE may declare RLF due to these issues.

[0036] Inability to comply with RRCReconfiguration

[0037] The specifications for cellular communications may be understood to define a control mechanism by which a NW node may provide a configuration that the UE may need to comply with. This configuration may enable new features, trigger handover, change an encryption key, etc. In 5G NR, the NW may send RRCReconfiguration messages to the UE for this purpose.

[0038] The NW may typically ensure that a configuration provided to the UE may be suitable. That is, that the UE may be able to comply with it. However, in some exceptional cases, the UE may not be able to comply with it. Possible reasons may be an error in the network, e.g., in the control plane, or some issue affecting the UE. For this reason, the specification may define a procedure that the UE may need to follow when it may be unable to comply with the configuration. In 5G NR, this procedure is described in TS 38.331 , v. 18.1.0, clause 5.3.5.8.2 and may consist of initiating RRC connection re-establishment, a procedure which is described in the section below with the heading “RRC connection re-establishment”.

[0039] Clause 5.3.5.8.2 of TS 38.331 , v. 18.1.0, describes the behaviour a UE may need to have when it may be unable to comply with RRCReconfiguration. The UE behaviour specified in this clause may be understood to not apply to the following, and the UE may ignore, that is, it may not take an action on and may not store, the fields that it may not support or may not comprehend: the fields in ServingCellConfigCommon that are defined in Rel-16 and later, and the fields of searchSpaceMCCH and searchSpaceMTCH in Physical Downlink Control Channel (PDCCH)- ConfigCommon that are defined in Rel-17 and later.

[0040] If the UE is unable to comply with the configuration, or part of it, included in the RRCReconfiguration message received over the Signalling Radio Bearer 1 (SRB1), or if the upper layers indicate that the nas-Container is invalid, and if RRCReconfiguration is received via NR, e.g., NR standalone, NR-E-UTRA Dual Connectivity (NE-DC), or NR-Dual Connectivity (DC), the UE may be required to continue using the configuration used prior to the reception of RRCReconfiguration message. Otherwise, the UE may be required to initiate the connection re-establishment procedure, upon which the reconfiguration procedure may end. If the UE is unable to comply with any part of the configuration included in the RRCReconfiguration message or if the upper layers indicate that the nas-Container is invalid and if RRCReconfiguration is received via another RAT, e.g., Handover to NR failure, the UE may be required to perform the actions defined for this failure case as defined in the specifications applicable for the other RAT.

[0041] The UE may apply the above failure handling also in case the RRCReconfiguration message may cause a protocol error for which the generic error handling as defined in clause 10 specifies that the UE may be required to ignore the message. If the UE is unable to comply with part of the configuration, it may not apply any part of the configuration. That is, there may be understood to no partial success / failure. It may be understood to be up to UE implementation whether the compliance check for an RRCReconfiguration received as part of Conditional Reconfiguration may be performed upon the reception of the message or upon CHO, CPA, Conditional PSCell Change (CPC), and subsequent Conditional PSCell Addition or Change (CPAC) execution, e.g., when the message may be required to be applied.

[0042] It may be understood to be up to UE implementation whether the compliance check for an RRCReconfiguration message received as part of an LTM-Config IE may be performed upon the reception of the message or during an LTM cell switch procedure, when the message may be required to be applied.

[0043] RRC connection re-establishment

[0044] When the connection between the NW and the UE is interrupted for some reason, e.g., multiple consecutive errors, a loss of synchronization, the inability to comply with an RRCReconfiguration described in the previous section, etc., the UE may be required to attempt to re-establish the connection with the NW. The procedure may comprise releasing existing configurations and resetting some connection and UE internals, such as buffers, configurations, states, etc., searching for a suitable cell and selecting it, and accessing the selected cell and transmitting the corresponding connection re-establishment messages.

[0045] In some cases, the UE may be configured by the network with some alternative serving cells, e.g., target candidate cells for conditional handover or for L1 / L2-triggered mobility (LTM). To recover the connection, the UE may attempt a shorter process only comprising searching for a suitable cell and selecting it, and, if the selected cell is one of the alternative serving cells configured by the network, the UE may initiate a mobility procedure to the selected cell. TS 38.331 , v. 18.1.0, describes the steps in the RRC connection re-establishment procedure in section 5.3.7.2. A selection from such steps includes the following actions. Upon initiation of the procedure, the UE may be required to perform cell selection in accordance with the cell selection process as specified in TS 38.304, v. 18.1.0. For an L2 UE to Network relay (U2N) Remote UE, if both a suitable cell and a suitable relay are available, the UE may select either one based on its implementation. Following cell selection and while T311 is running, the UE may perform the following actions. Upon selecting a suitable NR cell, the UE may be required to initiate transmission of the RRCReestablishmentRequest message in accordance. This procedure may be understood to apply also if the UE returns to the source Primary Cell (Pcell). An L2 U2N Relay UE may re-establish, e.g., via release and establish, the SL-RLCO and SL-RLC1 of the connected L2 Remote UE(s). Upon selecting an inter-RAT cell, the UE may be required to perform the actions upon going to RRCJDLE, with release cause 'RRC connection failure'.

[0046] Section 5.3.7.3 from TS 38.331 , v. 18.1.0, describes steps that may shorten the RRC connection re-establishment procedure, a selection of which is reproduced next. Following cell selection while T311 is running, upon selecting a suitable NR cell, if the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG or mobility from NR failure, if attemptCondReconfig is configured, if the selected cell is not configured with CondEventTI , or the selected cell is configured with CondEventTI and the leaving condition has not been fulfilled, if the selected cell is one of the candidate cells for which the reconfigurationWithSync is included in the masterCellGroup in the MCG VarConditional Reconfig and the condExecutionCondPSCell is not configured for the corresponding condReconfigld 'm the MCG VarConditionalReconfig and if the UE supports RLF- Report for conditional handover, the UE may be required to set the choCellld in the VarRLF- Report to the global cell identity, if available, otherwise to the physical cell identity and carrier frequency of the selected cell, and apply the stored condRRCReconfig associated to the selected cell and perform actions. It may be left to network implementation how to avoid keystream reuse in case of CHO based recovery after a failed handover without key change. If the cell selection is triggered by detecting radio link failure of the MCG or re-configuration with sync failure of the MCG or mobility from NR failure, if attemptLTM-Switch is configured; and if the selected cell is one of the LTM candidate cells in the LTM-Candidate IE within Itm-Config associated with the MCG, the UE may perform the LTM cell switch procedure for the selected LTM candidate cell. In case both attemptCondReconfig and attemptLTM-Switch are configured, it may be left to the UE implementation which procedure to execute.

[0047] Control plane

[0048] Control plane may be understood to refer to the set of procedures and associated signalling that may be used for controlling the connection between the NW and the UE. There may be multiple protocols that may perform some control tasks. In the RAN, the RRC layer may be responsible for many control tasks, including maintaining a connection between the UE and the RAN. Non-Access Stratum (NAS) control protocol may be understood to be responsible for establishing and maintaining a connection between the UE and the Core Network (CN).

[0049] The protocol stack for carrying control plane, that is, the Control Plane Protocol Stack, may be as illustrated in Figure 4, which reproduces Figure 4.4.2-1 of TS 38.300, v. 18.1.0, according to the following Control plane description in clause 4.4.2 of this specification. Figure 4 may be understood to show a connection for the control plane. Packet Data Convergence Protocol (PDCP) 41 , RLC 42 and MAC 43 sublayers, terminated in the gNB 44 on the network side may perform the functions listed in clause 6 of that specification, the RRC 45, terminated in the gNB 44 on the network side, may perform the functions listed in clause 7 of that specification; NAS control protocol 46, terminated in the AMF 47 on the network side, may perform the functions listed in TS 23.501 , v. 18.1.0, for instance: authentication, mobility management, and security control. Also depicted in Figure 4 are the PHYsical layer 48, and the terminations of each of the corresponding layers on the UE 49 side.

[0050] Failures in the connection of a UE with the network may result in delays and waste of network resources, which may degrade the performance of the network.

[0051] SUMMARY

[0052] As part of the development of embodiments herein, one or more challenges with the existing technology will first be identified and discussed.

[0053] In existing networks, unavailability of the Control Plane (CP) may typically lead to a failure of the entire connection, interrupting user plane traffic and the services running on top. Unavailability of the CP may typically result in the execution of the following procedures: declaration of radio Link failure, which may typically take ~2 seconds, performing cell search, which may take multiple seconds, and RRC connection re-establishment, which may take 100s of milliseconds.

[0054] In existing networks, there is no functionality to detect control plane failures.

[0055] In existing networks, there is no functionality to react to failures of the control plane in a way that it may be restored and the connectivity may be maintained.

[0056] According to the foregoing, it is an object of embodiments herein to improve the handling of an unavailability of a first protocol layer in a wireless communications network.

[0057] According to a first aspect of embodiments herein, the object is achieved by a computer- implemented method, performed by a first node. The method is for handling an unavailability of a first protocol layer. The first node operates in a wireless communications network. The first node sends an indication to a wireless device operating in the wireless communications network. The indication indicates to perform a reconfiguration. The indication is sent using signalling from a different layer than the first protocol layer between a second node and the wireless device, wherein the unavailability has been detected.

[0058] According to a second aspect of embodiments herein, the object is achieved by a computer-implemented method, performed by the wireless device. The method is for handling the unavailability of the first protocol layer. The wireless device operates in the wireless communications network. The wireless device receives the indication from the first node operating in the wireless communications network. The indication indicates to perform the reconfiguration. The indication is received using signalling from a different layer than the first protocol layer between the second node and the wireless device, wherein the unavailability has been detected.

[0059] According to a third aspect of embodiments herein, the object is achieved by a computer- implemented method, performed by a third node. The method is for handling the unavailability of the first protocol layer. The third node, operates in the wireless communications network. The third node determines the unavailability of the first protocol layer between the second node and the wireless device operating in the wireless communications network. The third node then sends the third indication to the first node operating in the wireless communications network. The third indication indicates the detected unavailability.

[0060] According to a fourth aspect of embodiments herein, the object is achieved by the first node. The first node is for handling the unavailability of the first protocol layer. The first node is configured to operate in the wireless communications network. The first node is configured to send the indication to the wireless device configured to operate in the wireless communications network. The indication is configured to indicate to perform the reconfiguration. The indication is configured to be sent using signalling from a different layer than the first protocol layer between the second node and the wireless device, wherein the unavailability is configured to have been detected.

[0061] According to a fifth aspect of embodiments herein, the object is achieved by the wireless device. The wireless device is for handling the unavailability of the first protocol layer. The wireless device is configured to operate in the wireless communications network. The wireless device is configured to receive the indication from the first node configured to operate in the wireless communications network. The indication is configured to indicate to perform the reconfiguration. The indication is configured to be received using signalling from a different layer than the first protocol layer between the second node and the wireless device, wherein the unavailability is configured to have been detected.

[0062] According to a sixth aspect of embodiments herein, the object is achieved by the third node. The third node is for handling the unavailability of the first protocol layer. The third node is configured to operate in the wireless communications network. The third node is configured to determine the unavailability of the first protocol layer between the second node and the wireless device configured to operate in the wireless communications network. The third node is also configured to, send the third indication to the first node configured to operate in the wireless communications network. The third indication is configured to indicate the unavailability configured to be detected.

[0063] By the third node determining the unavailability of the first protocol later and sending the third indication to the first node indicating the detected unavailability, the third node may enable the first node to perform early detection of unavailability of the first protocol layer between the wireless device and the second node. The first node may then be enabled to take appropriate remedial action.

[0064] By sending the indication to the wireless device indicating to perform the reconfiguration using signalling from a different layer than the first protocol layer wherein the unavailability has been detected, the first node may allow the NW to deal with connectivity problems, e.g., first protocol layer connectivity problems, avoiding that the wireless device is forced to declare RLF and perform cell search and RRC connection re-establishment procedures.

[0065] By leveraging signalling that may trigger mobility from a different layer, the first node may be able to address failures affecting the first protocol layer.

[0066] In this way, a detected control plane issue may be addressed in e.g., 50-100 ms.

[0067] The first node may therefore allow for prevention of interruptions of the service or reductions and / or minimizations of the time the service may be interrupted. Shortening the service interruption time to a nearly-deterministic low value may be necessary for connectivity service providers in order to be able to deliver performance guarantees.

[0068] BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Examples of embodiments herein are described in more detail with reference to the accompanying drawings, according to the following description.

[0070] Figure 1 is a signalling diagram depicting basic operations and signalling in conditional handover, according to existing methods.

[0071] Figure 2 is a signalling diagram depicting a procedure for CHO, according to Figure 9.2.3.2.1-1 in TS 38.300, v. 18.1.0.

[0072] Figure 3 is a signalling diagram depicting a procedure for LTM, according to Figure 9.2.3.5.2-1 of TS 38.300, v. 18.1.0.

[0073] Figure 4 is a signalling diagram depicting the Control Plane Protocol Stack, according to Figure 4.4.2-1 of TS 38.300, v. 18.1.0.

[0074] Figure 5 is a schematic diagram depicting an example of a wireless communications network, according to embodiments herein. Figure 6 is a flowchart depicting a method in a first node, according to embodiments herein. Figure 7 is a flowchart depicting a method in a wireless device, according to embodiments herein. Figure 8 is a flowchart depicting a method in a third node, according to embodiments herein.

[0075] Figure 9 is a schematic diagram depicting a non-limiting example of protocol stacks at the network and the UE, related to aspects of embodiments herein.

[0076] Figure 10 is a signalling diagram depicting a non-limiting example of methods performed by the first node, and the wireless device, according to embodiments herein.

[0077] Figure 11 is a signalling diagram depicting an non-limiting example of methods performed by the first node, the third node, and the wireless device, according to embodiments herein.

[0078] Figure 12 is a signalling diagram depicting another non-limiting example of methods performed by the first node, the third node, and the wireless device, according to embodiments herein.

[0079] Figure 13 is a signalling diagram depicting yet another non-limiting example of methods performed by the first node, the second node, the third node, and the wireless device, according to embodiments herein.

[0080] Figure 14 is a signalling diagram depicting another non-limiting example of methods performed by the first node, and the wireless device, according to embodiments herein.

[0081] Figure 15 is a signalling diagram depicting yet another non-limiting example of methods performed by the first node, and the wireless device, according to embodiments herein.

[0082] Figure 16 is a signalling diagram depicting another non-limiting example of methods performed by the first node, the second node and the wireless device, according to embodiments herein.

[0083] Figure 17 is a schematic block diagram illustrating an embodiments of a first node, according to embodiments herein.

[0084] Figure 18 is a schematic block diagram illustrating an embodiments of a wireless device, according to embodiments herein.

[0085] Figure 19 is a schematic block diagram illustrating an embodiment of a third node, according to embodiments herein.

[0086] DETAILED DESCRIPTION

[0087] Certain aspects of the present disclosure and their embodiments may provide solutions to the challenges described in the Background and Summary sections herein, or other challenges. Embodiments herein may be generally understood to relate to a method in a network for detecting a failure and triggering mobility. Particularly, embodiments herein may relate to a set of methods for assessing the availability of the control plane between a UE and the NW. The assessment may be performed by the NW and may determine whether the control plane logic at the NW or the UE may be operating correctly or not.

[0088] If the control plane is considered to be unavailable or broken, the NW may initiate or trigger a mobility procedure that may, for example, allow the UE to change serving cells.

[0089] Triggering of the mobility procedure may use signalling from a different layer than the control plane, e.g., a MAC CE such as in LTM.

[0090] There may be two groups of methods: mobility triggered by a failure of the NW-side of the CP and mobility triggered by a failure of the UE-side of the CP.

[0091] 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 embodiment.

[0092] Figure 5 depicts two non-limiting examples, in panel a) and panel b), respectively, of a wireless communications network 100, sometimes also referred to as a wireless communications system, wireless communications network, 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. In other examples, the wireless communications network 100 may be a newer system, e.g., a Sixth Generation (6G) system, with similar functionality. Yet in other examples, the wireless communications network 100 may, e.g., alternatively or in addition, 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. Yet in other examples, the wireless communications network 100 may 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 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. The wireless communications network 100 may support Machine Type Communications (MTC), enhanced MTC (eMTC), Internet of Things (loT) and / or Narrow Band loT (NB-loT). Thus, although terminology from 5G / NR and LTE 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.

[0093] The wireless communications network 100 may comprise a plurality of network nodes, whereof a network node 110 is depicted in the non-limiting example of Figure 5. The network node 110 may be radio network node, that is, 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.

[0094] The network node 110 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.

[0095] The wireless communications network 100 comprises a first node 111 , a second node 112, and a third node 113. Any of the first node 111 , the second node 112 and the third node 113 may be a network node. Any of the first node 111 , the second node 112 and the third node 113 may be comprised in the network node 110 .

[0096] In some embodiments, the first node 111 may be a Distributed Unit (DU). The first node 111 may be controlled by the second node 112 and / or the third node 113. The first node 111 may have a direct connection with a wireless device such as the wireless device 130 described below. In some examples, the first node 111 may have a capability to manage lower layers of a protocol stack such as a Radio Link Control (RLC) layer, the Medium Access Control (MAC) layer and some parts of the Physical (PHY) Layer. The first node 111 may be capable to perform one or more functions as, for example, described TS 38.401 , v. 17.4.0, section 6.2.1. The first node 111 may be, e.g., a gNB DU.

[0097] In some embodiments, the second node 112 may be a Central Unit (CU) having a capability to manage a Control Plane (CP). The second node 112 may be capable to perform one or more functions as, for example, described in TS 38.401 , v. 17.4.0, section 6.2.1. The second node 112 may be, e.g., a gNB CU, such as a gNB CU-CP.

[0098] The third node 113 may be an auxiliary network entity, In some embodiments, the third node 113 may be a different node than the second node 112. In other embodiments, the third node 113 may be the same node as the second node 112.

[0099] In some examples, any of the first node 111 , the second node 112 and the third node 113 may be co-located. In other examples, at least some of the first node 111 , the second node 112 and the third node 113 may not be co-located or be the same node. In particular examples, such as that depicted in Figure 5 a, none of the first node 111 , the second node 112 and the third node 113 may be co-located. In some embodiments, one of the following may apply: the first node 111 may be the same node as the second node 112, the first node 111 and the second node 112 may be comprised in a same network node, the second node 112 may manage the first node 111 , the first node 111 may be a distributed unit and the second node 112 may be a centralized unit.

[0100] In some embodiments, one of the following may apply: the third node 113 may be a different node than the second node 112 and the third node 113 may be the same node as the second node 112.

[0101] In particular examples, such as those depicted in Figure 5a and Figure 5 b, the network node 110 may be a distributed node, and may partially perform some of its functions in the cloud 115, wherein in some examples, the second node 112 and the third node 113 may be located.

[0102] 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 examples of Figure 5, the network node 110 serves a cell 120. The network node 110 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. In some examples, the network node 110 may serve receiving nodes with serving beams. The network node 110 may support one or several communication technologies, and its name may depend on the technology and terminology used.

[0103] A plurality of wireless devices may be located in the wireless communication network 100, whereof a wireless device 130, is depicted in the non-limiting example of Figure 5. The wireless device 130 comprised in the wireless communications network 100 may be a wireless communication device such as a User Equipment (UE), e.g., UE, 5G UE or nUE, 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. The wireless device 130 may be, for example, portable, pocket-storable, hand-held, 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 a headset, goggles, 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. The wireless device 130 comprised in the wireless communications network 100 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. The first node 111 may be configured to communicate with the third node 113 over a first link 141 , e.g., a wired link. The second node 112 may be configured to communicate with the first node 111 over a second link 142, e.g., a wired link. The second node 112 may be configured to communicate with the third node 113 over a third link 143, e.g., a wired link. The wireless device 130 may be configured to communicate within the wireless communications network 100 with the first node 111 , over a fourth link 144, e.g., a radio link.

[0104] This disclosure may use 5G NR terminology, procedures, architecture, etc. for the purpose of illustration. However, the embodiments described herein may be understood to be applicable to other radio access technologies (RATs), such as an upcoming 6G RAT.

[0105] 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.

[0106] 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, unless otherwise noted, based on context.

[0107] Several embodiments are comprised herein. 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.

[0108] Some embodiments herein will now be further described with some non-limiting examples, which may be combined with the embodiments just described.

[0109] Embodiments of a computer-implemented method, performed by the first node 111 , will now be described with reference to the flowchart depicted in Figure 6. The method is for handling an unavailability of a first protocol layer. The first node 111 operates in the wireless communications network 100.

[0110] In some embodiments, the wireless communications network 100 may be a 5G network. In some embodiments, the first node 111 may be a DU.

[0111] The first protocol layer may be an RRC layer.

[0112] Several embodiments are comprised herein. The method may comprise one or more of the other actions described next in relation to Figure 6. In some embodiments, all the actions may be performed. In particular embodiments, the method comprises Action 605. One or more embodiments may be combined, where applicable. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. 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. All possible combinations are not described to simplify the description. A non-limiting example of the method performed by the first node 111 is depicted in Figure 6. In Figure 6 optional actions in some embodiments may be represented with dashed lines. In some embodiments, the actions may be performed in a different order than that depicted Figure 6.

[0113] Embodiments herein may be understood to relate to a set of methods for detecting failures in the control plane between the wireless device 130, e.g., a UE, and a network node, e.g., the second node 112, for example, a base station, a gNB, etc and corresponding signalling to trigger mobility of the wireless device 130, that is, hand over, for the purpose of resilience, that is, to release connectivity from a malfunctioning part of the system and to connect to a functional one.

[0114] Action 601

[0115] In some embodiments, the method may comprise one or more of Action 601 and Action 602. Any of Action 601 and Action 602 may be understood to correspond to a CP availability check protocol, which may be comprised in some examples of embodiments herein.

[0116] According to the CP availability check protocol, availability test messages may be exchanged between the CP of the wireless device 130 and the CP of the network. Such signals may be unidirectional (1-way) or bidirectional (2-ways). In some non-limiting examples, the CP of the network may be run by the first node 111.

[0117] For bidirectional availability messages, according to the CP availability check protocol, the network, for example, the first node 111 , e.g., a gNB, may send a first “availability check” message to the wireless device 130, which in turn may process the message and may send a second “availability check” message to the network, for example, the first node 111 , e.g., the gNB, as will be described in Action 602.

[0118] In this Action 601 , the first node 111 may send, to the wireless device 130, a first indication requesting a first availability check of the first protocol layer. The first protocol layer is between the second node 112 and the wireless device 130. The second node 112 may manage the first node 111. The first indication may be understood in some examples, as an availability check message.

[0119] In some embodiments, the second node 112 may be a centralized unit.

[0120] In some embodiments, the first node 111 may be a distributed unit and the second node 112 may be a centralized unit.

[0121] The first node 111 and the second node 112 may be comprised in a same network node 110, e.g., a gNB.

[0122] In some embodiments, the first node 111 may be the same node as the second node 112.

[0123] By sending the first indication in this Action 601 , the first node 111 may then be enabled to receive in the next Action 602, or not, a second indication from the wireless device 130 in response, and thereby be enabled to determine, in Action 604, whether or not the first protocol layer may be unavailable. In some examples, this may be since the receiver of a response to the first indication may have the possibility of verifying with high confidence if the CP protocol operates correctly by performing an integrity check based on the content and encoding of the response, as will be described later.

[0124] Further details of the first indication are provided in the description of Action 602.

[0125] Action 602

[0126] In some embodiments, in this Action 602, the first node 111 may receive, from the wireless device 130, a second indication indicating a second availability check of the first protocol layer.

[0127] The second indication may be understood in some examples, as an availability check message.

[0128] For unidirectional availability messages according to the CP availability check protocol, the wireless device 130 may, in this Action 602, deliver an “availability check” message, which may be received by the network, in this embodiment, the first node 111 , e.g., the gNB.

[0129] For bidirectional availability messages according to the CP availability check protocol, the network, for example, the first node 111 may have sent a first “availability check” message to the wireless device 130 in Action 601 , which in turn may process the message and may send a second “availability check” message to the network, for example, the first node 111 , e.g., the gNB, in this Action 602.

[0130] In one example, the “availability check” messages, that is, any of the first indication of Action 601 and the second indication of this Action 602, both in case of unidirectional or bidirectional protocols, may include means for verifying the integrity of the message and / or that the function that generated the message content may be functional. For example, the message may include pseudo-random bits, timestamps based on local timing or other synchronization reference, such as the radio frame number, parity bits, a CRC. Some identity or key which may be expected to be known to the transmitter and receiver may be added to the message or be used to scramble, encrypt, encode or hash the message. In this way, the receiver may have the possibility of verifying with high confidence if the CP protocol operates correctly by performing an integrity check based on the content and encoding defined above.

[0131] In one example, a node, such as the first node 111 , may have rules for generating and / or transmitting the “availability check” message. The rules may define under which conditions it may or may not generate and / or transmit a message.

[0132] In one example, a node, such as the first node 111 , may be expected to generate and / or transmit an “availability check” message only at most N times in a period of T seconds, e.g., 1 time every T seconds, etc.

[0133] In one example, a node, such as the first node 111 , may be allowed to generate and / or transmit an “availability check” message, only if the time since it last received an “availability check” message from the peer node is T seconds or more. For example, A may have a timer that may be reset every time that the A may receive a message from B. If the timer expires, A may be allowed to, or may be required to, generate and / or transmit a first message. The type of messages that may reset the timer may be restricted. In the following section, types of second “availability check” messages are described. The discussion may be applicable as well for messages resetting the timer discussed here.

[0134] The time T may be configured by the network, for example, the first node 111 , and / or may be related to a QoS requirement, such as an allowed service interruption time (ASIT) or maximum service interruption time (SIT).

[0135] In one example, a CP message transmitted for other purposes may be regarded as an “availability check” message, e.g., any dedicated message, or any message including broadcast messages, etc., hence reducing the need for signalling when other CP messaging may be ongoing. In one example, the “availability check” message of any of the first indication and the second indication may be any message in a group of messages, e.g., any message that may be part of the set of RRC messages, any message carrying a given information element, any control plan message, any message originating from a CU, any user plane message, any message originating from a DU; etc.

[0136] An “availability check” message of any of the first indication and the second indication may be a predefined message, or it may be a function of the previously received “availability check” message. For example, part of the content of a previous message, such as a key or a timestamp, may be included in the second message. In one example, the second “availability check” message may depend on the first message. For example, a field in the response message may be obtained using a field in the first message, e.g., copying; applying a function, etc. Potentially, an acknowledgment of correct reception, e.g., an integrity check, of the first message may be included. This may allow the receiver of the second message to assess whether the CP protocol operates correctly in a bidirectional way. By receiving, or not, the second indication in this Action 602, the first node 111 may then be enabled to determine, in Action 604, whether or not the first protocol layer may be unavailable. In some examples, this may be since the receiver of a response to the first indication may have the possibility of verifying with high confidence if the CP protocol operates correctly by performing an integrity check based on the content and encoding of the response, or by a failure to receive the response within a certain time window, as will be later.

[0137] Action 603

[0138] In this Action 603, the first node 111 may receive a third indication from the one of the wireless device 130, the second node 112 and the third node 113 having detected an unavailability of the first protocol layer.

[0139] The third indication may indicate the detected unavailability.

[0140] The second node 112 may be understood to be the node running the first protocol layer wherein the unavailability may have been detected.

[0141] The unavailability may be of a control plane. In embodiments herein, the control plane may be understood to refer to a set of procedures and corresponding signalling that may be used by the wireless device 130 and the network, that is, the second node 112, to exchange messages related to control operations, e.g., commands, configurations, system information, reports, etc. The RRC layer may be understood to be an example of control plane in cellular communication systems, such as 5G NR.

[0142] This disclosure may be understood to be largely presented for the case that control plane may refer to the functionality provided by the RRC layer. However, the principle may be understood to be applicable to other types of control plane.

[0143] The unavailability may be a failure.

[0144] The unavailability of the control plane may be caused by the network, e.g., the hardware or software in the network that may be responsible for control plane operations may be malfunctioning, e.g., by the second node 112, or by the wireless device 130, e.g., the hardware or software in the wireless device 130 that may be responsible for control plane operations may be malfunctioning.

[0145] Each case is treated separately below, in Group 1 and Group 2, respectively.

[0146] Group 1 : NW failures

[0147] This group of examples may be understood to address the case that the failure in the control plane may be caused by the NW, e.g., by the second node 112.

[0148] The method in this group may be a method in the network, e.g., one of the first node 111 , the second node 112 and the third node 113, for detecting a failure of the control plane logic in the network and signalling to the wireless device 130 that may trigger mobility of the wireless device 130. In one example, the protocol layer for signalling may be understood to be different from the protocol layer for which a failure may have been detected. For example, a failure in the RRC control plane may be dealt with by using signalling from a lower layer, such as the MAC layer, e.g., transmitting a MAC CE.

[0149] Each aspect of the method may be executed by a different entity, e.g., a node or a function, in the network.

[0150] In one example, the same network entity, e.g., the first node 111 , may execute all parts of the method. For example, an integrated base station may: run the control plane which may fail, e.g., the RRC layer, have some functionality to detect the failure of the control plane, and have some functionality to send the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHYsical (PHY) layers and the radio unit. Accordingly, in some embodiments, the first node 111 may be the same node as the second node 112.

[0151] In one example, separate network entities may run the control plane which may fail, e.g., the RRC layer in a Centralized Unit (CU), e.g., the second node 112, and have some functionality to send the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHY layers in a Distributed Unit (DU), such as the first node 111 . Accordingly, in some examples, the first node 111 may be a different node than the second node 112.

[0152] The functionality to detect the failure of the control plane may be part of the first element, that is, the second node 112, e.g., the CU, or the second element, that is, the first node 111 , e.g., the DU, or a third element, that is, the third node 113, e.g., a separate node or function that may be responsible for detecting failures and notifying the second element so that it may take the corresponding actions.

[0153] Accordingly, the unavailability may be detected by one of the first node 111 , the second node 112 and the third node 113.

[0154] Different realizations are illustrated in Figure 5, Figure 6, Figure 7, and Figure 8.

[0155] In some examples, the NW entity running the control plane, the second node 112, may be also responsible for detecting the failure. Upon detection, the second node 112 may notify the first node 111 in this Action 603.

[0156] Group 2: UE failures

[0157] This group of methods and examples may be understood to address the case that the failure in the control plane may be caused by the wireless device 130.

[0158] A method in this group may be a method in the network for detecting a failure of the control plane logic in the wireless device 130, and signalling to the wireless device 130 that may trigger mobility of the wireless device 130.

[0159] As stated earlier for NWfailures, each aspect of the method may be executed by a different entity, e.g., a node or a function, in the network. In one example, the same network entity, e.g., the first node 111 , may execute all parts of the method. For example, an integrated base station may have some functionality, e.g., according to Action 604, to detect the failure of the control plane at the wireless device 130 and have some functionality, according to Action 605 described later, to prepare and / or send the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHY layers and the radio unit.

[0160] In another example, one network entity, e.g., a gNB CU, such as the second node 112 or the third node 113, may have some functionality to detect the failure of the control plane at the wireless device 130. Another network entity, e.g., a gNB DU, such as the first node 111 , may have the necessary functionality to prepare and / or send the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHY layers in a gNB DU.

[0161] In one example, the protocol layer for signalling may be different from the protocol layer for which a failure may have been detected. For example, as stated earlier, a failure in the RRC control plane may be dealt with by using signalling from a lower layer, such as the MAC layer, e.g., transmitting a MAC CE.

[0162] In some embodiments, the third indication may be received using signalling from a different layer than the first layer of the first protocol layer between the second node 112 and the wireless device 130. That is, the layer wherein the unavailability may have been detected.

[0163] In some embodiments, the different layer may be a MAC layer and the first protocol layer may be an RRC layer.

[0164] Detection of the failure

[0165] In one example, the failure may be detected by means of keep-alive messaging, e.g., a watchdog. The watchdog may be established between the function that may be expected to detect control plane failures and the monitored function, or some other function affecting control plane availability, e.g., a cloud platform hosting the CU. If no message is received from the part handling the control plane in the NW, that is, the second node 112, within a certain time, then it may be determined that the control plane in the NW, that is, in the second node 112, has failed or is failing.

[0166] In one example, the failure may be detected by means of some request / response signalling. The part handling the control plane in the NW, that is, the second node 112, may be expected to respond to every request message, with a response message. If it does not respond to one message, or a number of them during some time period(s), then it may be determined, e.g., in the next Action 604 by the first node 111 , that the control plane in the NW has failed or is failing.

[0167] Detection of the failure in the wireless device 130 and subsequent signalling

[0168] All the examples so far have focused on detection by the NW itself, that is, by one of the first node 111 , the second node 112 and the third node 113. Embodiments herein may also comprise the case that the detection may be carried by the wireless device 130. That is, the wireless device 130 may detect a failure concerning the communication with the NW, e.g., the control plane, and it may notify this to the Network, e.g., the first node 111 , in this Action 603 by sending the third indication. In response to receiving this notification, the NW, that is, the first node 111 , may then trigger mobility following the approaches and embodiments described herein in Action 605. The wireless device 130 may detect the failure by means of keep-alive messages or request / response signalling in a similar way as explained before, but with the wireless device 130 in the detecting role. This is illustrated in Figure 14.

[0169] As explained earlier for the message triggering mobility, notification of the condition or failure via the third indication in this Action 603 may require using a control message from a different layer than the one where the failure has been detected. For example, a MAC CE may be used by the wireless device 130 to indicate to the NW, e.g., the first node 111 in this Action 603, about the detected failure.

[0170] By receiving the third indication in this Action 603, the first node 111 may then be enabled to determine, in Action 604, whether or not the first protocol layer may be unavailable and allow for early detection of unavailability in the control plane between the wireless device 130 and the NW. The first node 111 may then be enabled to take appropriate remedial action.

[0171] Action 604

[0172] In this Action 604, the first node 111 may determine the unavailability of the first protocol layer.

[0173] Determining may be understood as calculating, detecting or deriving.

[0174] The determining in this Action 604 of the unavailability may be based on one or more of the first indication and the second indication. This may be understood to correspond to the CP availability check protocol.

[0175] For unidirectional availability messages, the wireless device 130 may have delivered an “availability check” message, which may be received by the first node 111 in Action 602. The first node 111 may process the content of the message, together with other conditions such as the expiry of a timer, and determine whether CP may be available, or not in this Action 604.

[0176] For bidirectional availability messages, the first node 111 may have sent a first “availability check” message to the wireless device 130 in Action 601 , which in turn may process the message and may send a second “availability check” message to the first node 111 in Action 602. The first node 111 may process the content of the message, together with other conditions such as the expiry of a timer or the content of the first availability check message, and may determine whether CP may be available, or not in this Action 604.

[0177] In some embodiments, the determining in this Action 604 of the unavailability may be based on the received third indication. The unavailability may be detected by one of the first node 111 , the second node 112 and the third node 113.

[0178] In some examples, a single NW entity, the first node 111 , may be responsible for running the control plane, which may fail and detecting the failure. That is, in some examples, the first node 111 may be the same node as the second node 112.

[0179] In particular examples, the second node 112, may run the control plane, which may fail and the first node 111 , may monitor the state of the control plane to detect failures.

[0180] In another realization of the method for NW failures, the third node 113 may be an auxiliary function that may be responsible for detecting failures of the control plane in the NW.

[0181] In some embodiments, one of the following may apply. According to one option, the unavailability may be detected by a different node than the second node 112 running the first protocol layer wherein the unavailability may have been detected. According to another option, the unavailability may be detected by the second node 112 running the first protocol layer wherein the unavailability may have been detected.

[0182] By determining the unavailability of the first protocol layer in this Action 604, the first node 111 may allow for early detection of unavailability in the first protocol layer between the wireless device 130 and the second node 112. The first node 111 may then be enabled to take appropriate remedial action in Action 605.

[0183] Action 605

[0184] In this Action 605, the first node 111 sends an indication to the wireless device 130 operating in the wireless communications network 100. The sent indication in this Action 605 may be referred to as a fourth indication.

[0185] The indication, that is, the fourth indication, indicates to perform a reconfiguration. The indication is sent using signalling from a different layer than the first protocol layer between the second node 112 and the wireless device 130, wherein the unavailability has been detected.

[0186] As stated earlier, the unavailability may be of the control plane. In embodiments herein, mobility may be triggered using signalling from a different set of procedures and protocols than the control plane with availability issues. Most importantly, conveying the triggering signalling may be understood to not rely on the control plane being functional. For example, the signalling may be independent.

[0187] For example, if RRC-layer communication is impaired, communication between the control logic in the NW, e.g., the second node 112, and the control logic in the wireless device 130 to initiate mobility may be understood to not be possible.

[0188] Although RRC-layer communication may be impaired, communication between the control logic in the first node 111 and the control logic in the wireless device 130 to initiate mobility may be possible, according to embodiments herein, by using a different protocol, e.g., the MAC layer, for signalling. The control logic in the first node 111 may be able to communicate with the control logic in the wireless device 130 to initiate mobility in response to a failure of the control (RRC) layer.

[0189] Signalling in the RRC layer may be carried by RRC messages, whereas control signalling in the MAC layer may be carried by MAC Control Elements (MAC CEs). Therefore, a failure of the RRC layer may prevent the transmission of RRC messages between the wireless device 130 and the network, e.g., the second node 112.

[0190] For example, a failure may be detected in the Layer 3 implementation, e.g., in the software and / or hardware responsible for the RRC protocol; or in the Centralized Unit Control Plane (CU- CP) of the second node 112, e.g., a gNB, and L1 / L2-triggered mobility may be used for commanding the wireless device 130 to switch to a different cell in which the Layer 3 may be operating normally.

[0191] In some embodiments, the indication, that is, the fourth indication, may be a Medium Access Control (MAC) Information Element (IE).

[0192] It may be noted that a relationship between the control plane and the triggering signalling may not be excluded. For example, in 5G NR, the control plane may be used to configure certain aspects of triggering signalling, such as the MAC CEs used for conveying the LTM cell switch commands.

[0193] The unavailability may have been detected by one of: the wireless device 130, the first node 111 , the second node 112 and a third node 113, as explained earlier.

[0194] In some embodiments, the indication, that is, the fourth indication, may be a DCI.

[0195] In some embodiments, the indication, that is, the fourth indication, may be a Radio Resource Control (RRC) reconfiguration message.

[0196] The reconfiguration may be one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration may be used for changing beams.

[0197] In some embodiments, the RRC reconfiguration may be comprised in a mobility procedure. The mobility procedure may be one of: an inter-cell mobility and an intra-cell mobility.

[0198] In some examples, a single NW entity, the first node 111 , may be responsible for running the control plane, which may fail, detecting the failure, and preparing and / or sending to the wireless device 130 the signalling that may trigger mobility in this Action 605.

[0199] In some examples, the first node 111 , may be responsible for preparing and / or sending to the wireless device 130 the signalling that may trigger mobility. For example, the second node 112 may be a gNB CU, the first node 111 may be a gNB DU, and the mobility trigger may be a LTM cell switch command.

[0200] When it comes to mobility of the wireless device 130 triggered by the NW, e.g., by the first node 111 in this Action 605, handover may be understood to be the primary procedure considered here. However, other reconfiguration procedures of the wireless device 130 may be considered as well, including for example fast reconnection or RRC re-establishment procedures, or procedures for fallback to a pre-configured RRC configuration.

[0201] In some embodiments, the determining in Action 604 of the unavailability may be based on the received third indication, and the sent indication in this Action 605 may be the fourth indication sent responsive to the received third indication.

[0202] As stated earlier, in some examples, each aspect of the method may be executed by a different entity, e.g., a node or a function, in the network. Different entities in the NW may be responsible for detecting failures of the CP in the wireless device 130 and for and triggering mobility of the wireless device 130.

[0203] In some embodiments, one or more of the following may apply. According to one option, the first node 111 may be the same node as the second node 112. In some examples, the first node 111 may be a NW entity that may prepare and / or send the signalling triggering mobility and may also be responsible for detecting the failure in the control plane in the NW.

[0204] In one example, the same network entity, e.g., the first node 111 , may execute all parts of the method. For example, an integrated base station may have some functionality, e.g, the first node 111 , to detect the failure of the control plane at the wireless device 130 and have some functionality, according to Action 605 described later, to prepare and / or send the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHY layers and the radio unit.

[0205] In other examples, each aspect of the method may be executed by a different entity, e.g., a node or a function, in the network. The first node 111 may be understood as the node that may indicate to the wireless device 130 to perform a reconfiguration. The second node 112 may be understood as the node that may signal with the wireless device 130 with the first protocol layer wherein the unavailability has been detected.

[0206] In another example, one network entity, for example, the second node 112 or the third node 113, e.g., a gNB CU, may have some functionality to detect the failure of the control plane at the wireless device 130. Another network entity, for example, the first node 111 , e.g., a gNB DU, may have the necessary functionality to prepare and / or send the signalling to the wireless device 130 as described later in Action 605, that may trigger the mobility, e.g., the MAC and PHY layers in a gNB DU.

[0207] According to another option, the first node 111 and the second node 112 may be comprised in a same network node 110.

[0208] In one example, the same network entity, e.g., the network node 110, may execute all parts of the method. For example, an integrated base station may have some functionality, e.g., the first node 111 , to detect the failure of the control plane at the wireless device 130 and have some functionality to prepare and / or send the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHY layers and the radio unit.

[0209] According to yet another option, the second node 112 may manage the first node 111.

[0210] According to another option, the first node 111 may be a distributed unit and the second node 112 may be a centralized unit.

[0211] According to another option, the indication, that is, the fourth indication, may be a Medium Access Control (MAC) Information Element (IE). Whenever RRC-level communication is impaired, it may no longer be possible to use RRC signalling between the wireless device 130 and the network, e.g., the second node 112 and / or the first node 111 , e.g., gNB, for triggering mobility. Consequently, in the event of a failure of the RRC-level communication, it would not be possible to use RRC signalling to remediate it. That is, the control logic in the first node 111 may no longer be able to communicate with the control logic in the wireless device 130 to initiate mobility. Signalling from a different layer may be used instead. In one example, the protocol layer for signalling may be different from the protocol layer for which a failure may have been detected. For example, as stated earlier, a failure in the RRC control plane may be dealt with by using signalling from a lower layer, such as the MAC layer, e.g., transmitting a MAC CE.

[0212] According to another option, the indication, that is, the fourth indication, may be a DCI.

[0213] According to yet another option, the indication, that is, the fourth indication, may be a Radio Resource Control (RRC) reconfiguration message.

[0214] According to a further option, the reconfiguration may be one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration may be used for changing beams.

[0215] According to an additional option, the RRC reconfiguration may be comprised in a mobility procedure. Upon detection, the first node 111 may prepare / send to the wireless device 130 the signalling that may trigger mobility.

[0216] According to yet another option, the mobility procedure may be one of: an inter-cell mobility and an intra-cell mobility.

[0217] For example, the second node 11 , may be a gNB CU, the first node 111 may be a gNB DU, and the mobility trigger may be a LTM cell switch command.

[0218] According to a further option, the unavailability has been detected by one of: the wireless device 130, the first node 111 , the second node 112 and a third node 113.

[0219] According to another option, the unavailability may be a failure.

[0220] According to yet another option, the different layer may be a MAC layer and the first protocol layer may be an RRC layer.

[0221] According to a further option, the unavailability may be of the control plane.

[0222] Application to other protocols The description has focused so far on detecting a failure concerning a layer that may be understood to be a control layer, and using a different layer with control functionality to trigger mobility. However, the same principles may be applicable to detection of failure concerning layers that may not be control layers.

[0223] For example, a failure may be detected in the implementation of higher layers of the User Plane (UP) protocol stack, e.g., in the PDPC or Service Data Adaptation Protocol (SDAP) layers, and L1 / L2-triggered mobility may be used for commanding the wireless device 130 to switch to a different cell in which the higher layers of the UP protocol stack may be operating normally.

[0224] Similarly, a failure may be detected in the implementation of middle layers of the protocol stack, e.g., the RLC layer, preventing the use of higher layer signalling such as RRC for solving the issue by means of mobility. In this case, L1 / L2-triggered mobility, using MAC CEs, may be used for commanding the wireless device 130 to switch to a different cell in which the higher layers of the UP protocol stack may be operating normally.

[0225] By sending the fourth indication to the wireless device 130 in this Action 605, the first node 111 may allow for prevention of interruptions of the service or reductions and / or minimizations of the time the service may be interrupted. Shortening the service interruption time to a nearly-deterministic low value may be necessary for connectivity service providers in order to be able to deliver performance guarantees.

[0226] By leveraging signalling that may trigger mobility from a different layer, the first node 111 may be able to address failures affecting the first protocol layer, e.g. the CP.

[0227] By leveraging mobility procedures, the first node 111 n may allow the NW to deal with first protocol layer connectivity problems, e.g., CP connectivity problems, avoiding that the wireless device 130 is forced to declare RLF and perform cell search and RRC connection reestablishment procedures.

[0228] In this way, a detected control plane issue may be addressed in 50-100 ms.

[0229] Embodiments of a computer-implemented method performed by the wireless device 130, will now be described with reference to the flowchart depicted in Figure 7. The method is for handling the unavailability of the first protocol layer. The wireless device 130 operates in the wireless communications network 100.

[0230] Several embodiments are comprised herein. The method may comprise more of the following actions. In some embodiments, all the actions may be performed. In a particular example, Action 705 is performed. One or more embodiments may be combined, where applicable. 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. All possible combinations are not described to simplify the description. A non-limiting example of the method performed by the wireless device 130 is depicted in Figure 7. In Figure 7, optional actions in some embodiments may be represented with dashed lines. In some embodiments, the actions may be performed in a different order than that depicted Figure 7.

[0231] The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first node 111 and will thus not be repeated here to simplify the description. For example, the failure may be detected by means of keep-alive messaging, e.g., a watchdog.

[0232] Action 701

[0233] In some embodiments, the method may comprise one or more of Action 701 and Action 702.

[0234] In this Action 701 , the wireless device 130 may receive the first indication.

[0235] The receiving in this Action 701 may be from the first node 111.

[0236] The first indication may request a first availability check of the first protocol layer from one of: the first node 111 , the second node 112 and the third node 113.

[0237] Action 702

[0238] In this Action 702, the wireless device 130 may send the second indication.

[0239] The sending in this Action 702 may be to the first node 111.

[0240] The second indication may indicate a second availability check of the first protocol layer to the one of the first node 111 , the second node 112 and the third node 113.

[0241] Action 703

[0242] In some embodiments, the unavailability may be detected by one of the first node 111 , the second node 112 and the third node 113.

[0243] In some embodiments, one of the following may apply: a) the unavailability may be detected by a different node than the second node 112 running the first protocol layer wherein the unavailability may have been detected, and b) the unavailability may be detected by the second node 112 running the first protocol layer wherein the unavailability may have been detected.

[0244] In this Action 703, the wireless device 130 may determine the unavailability of the first protocol layer.

[0245] Action 704

[0246] In this Action 704, the wireless device 130 may send the third indication to the first node 111. The third indication may indicate the determined unavailability. In some embodiments, the third indication may be sent using signalling from a different layer than the first layer of the first protocol layer between the second node 112 and the wireless device 130.

[0247] In some embodiments, the method may comprise Action 703 and Action 704.

[0248] Action 705

[0249] In this Action 705, the wireless device 130 receives the indication from the first node 111 operating in the wireless communications network 100. The indication indicates to perform a reconfiguration. The indication is received using signalling from a different layer than the first protocol layer between the second node 112 and the wireless device 130, wherein the unavailability has been detected.

[0250] In some embodiments, the received indication may be the fourth indication received responsive to the sent third indication.

[0251] In some embodiments, one or more of the following may apply: a) the first node 111 may be the same node as the second node 112, b) the first node 111 and the second node 112 may be comprised in the same network node 110, c) the second node 112 may manage the first node 111 , d) the first node 111 may be a distributed unit and the second node 112 may be a centralized unit, e) the unavailability may be of the control plane, f) the indication may be a MAC IE, g) the indication may be a DCI, h) the indication may be an RRC reconfiguration message, i) the reconfiguration may be one of: the RRC reconfiguration, the reconfiguration of the transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration may be used for changing beams, j) the RRC reconfiguration may be comprised in a mobility procedure, k) the mobility procedure may be one of: an inter-cell mobility and an intra-cell mobility, I) the unavailability may have been detected by one of: the wireless device 130, the first node 111 , the second node 112 and the third node 113, m) the unavailability may be a failure, and n) the different layer may be a MAC layer and the first protocol layer may be an RRC layer.

[0252] Embodiments of a computer-implemented method performed by third node 113, will now be described with reference to the flowchart depicted in Figure 8. The method is for handling the unavailability of the first protocol layer. The third node 113, operates in the wireless communications network 100.

[0253] Several embodiments are comprised herein. The method may comprise more of the following actions. In some embodiments, all the actions may be performed. In a particular embodiments, Action 801 and Action 802 are performed. One or more embodiments may be combined, where applicable. 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. All possible combinations are not described to simplify the description. A non-limiting example of the method performed by the third node 113 is depicted in Figure 8. In Figure 8, optional actions in some embodiments may be represented with dashed lines. In some embodiments, the actions may be performed in a different order than that depicted Figure 8.

[0254] The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first node 111 and will thus not be repeated here to simplify the description. For example, the failure may be detected by means of keep-alive messaging, e.g., a watchdog.

[0255] Action 801

[0256] In this Action 801 , the third node 113 determines the unavailability of the first protocol layer between the second node 112 and the wireless device 130 operating in the wireless communications network 100.

[0257] The determining in this Action 801 may be performed as described for the first node in Action 604.

[0258] Action 802

[0259] The third node 113, in this Action 802, sends the third indication to the first node 111 operating in the wireless communications network 100. The third indication indicates the detected unavailability.

[0260] In some embodiments, the third indication may be sent using signalling from a different layer than the first layer of the first protocol layer between the second node 112 and the wireless device 130.

[0261] In some embodiments, one or more of the following may apply: a) the first node 111 may be the same node as the second node 112, b) the first node 111 and the second node 112 may be comprised in the same network node 110, c) the second node 112 may manage the first node 111 , d) the first node 111 may be a distributed unit and the second node 112 may be a centralized unit, e) the unavailability may be of the control plane, and f) the unavailability may be a failure.

[0262] In some embodiments, one of the following may apply. According to one option, the third node 113 may be a different node than the second node 112 running the first protocol layer wherein the unavailability may have been detected. According to another option, the third node 113 may be the same node as the second node 112. This use of alternative layers for triggering mobility in response to a failure is illustrated in Figure 9. Figure 9 is a schematic diagram depicting protocol stacks at the NW, that is, here, a the network node 110, and the wireless device 130, here a UE. The protocol stacks depicted are RRC, PDCP, RLC, MAC and PHY. Panel a) illustrates a case wherein RRC-layer communication is impaired, thus communication between the control logic in the second node 112 and the control logic in the wireless device 130 to initiate mobility is not possible. Panel b) illustrates a case wherein, although RRC-layer communication is impaired, communication between the control logic in the first node 111 , represented as the NW and the control logic in the wireless device 130, represented as a UE, to initiate mobility may be possible by using a different protocol, according to embodiments herein. On panel a), the default or legacy case is illustrated, in which RRC signalling between the UE 91 and the NW 92, e.g., gNB, may be used for triggering mobility. Whenever RRC-level communication is impaired, this may no longer be possible. Consequently, in the event of a failure of the RRC-level communication, it would not be possible to use RRC signalling to remediate it. That is, the control logic in the NW 92 cannot communicate with the control logic in the UE to initiate mobility. Panel b) illustrates a case wherein signalling from a different layer may be used instead, according to embodiments herein. Whenever RRC-level communication is impaired, this may be made possible by using a different layer, e.g., the MAC layer in this case, for signalling. That is, the control logic in the first node 111 , represented as the NW, may communicate with the control logic in the wireless device 130 to initiate mobility in response to a failure of the control (RRC) layer.

[0263] Signalling in the RRC layer may be carried by RRC messages, whereas control signalling in the MAC layer may be carried by MAC Control Elements (MAC CEs). Therefore, a failure of the RRC layer may prevent the transmission of RRC messages between the wireless device 130 and the NW

[0264] For example, a failure may be detected in the Layer 3 implementation, e.g., in the software and / or hardware responsible for the RRC protocol; or in the Centralized Unit Control Plane (CU- CP) of the second node 112, e.g., a gNB, and L1 / L2-triggered mobility may be used for commanding the wireless device 130 to switch to a different cell in which the Layer 3 may be operating normally.

[0265] The unavailability of the control plane may be caused by the network, e.g., the hardware or software in the network that may be responsible for control plane operations may be malfunctioning, or by the wireless device 130, e.g., the hardware or software in the wireless device 130 that may be responsible for control plane operations may be malfunctioning.

[0266] Figure 10 is a signalling diagram illustrating a realization of the method for NW failures in which a single NW entity, the first node 111 , may be responsible for all steps. In Figure 10, a single entity, the first node 111 , may be responsible for, running the control plane, which may be understood to fail, detecting the failure according to Action 604, and preparing and / or sending to the wireless device 130 the signalling that may trigger mobility according to Action 605 and Action 705.

[0267] Figure 11 is another signalling diagram illustrating another realization of the method for NW failures in which the NW entity running the control plane may be also responsible for detecting the failure. In Figure 11, the second node 112 may be the same node as the third node 113, depicted as NW entity 1 , may run the control plane, which fails, and may be also responsible for detecting the failure according to Action, 801 . Upon detection, the third node 113 may, according to Action 802 and Action 603, notify the first node 111 , depicted as NW entity 2. The first node 111 , NW entity 2, may be responsible for preparing and / or sending to the wireless device 130 the signalling that may trigger mobility, according to Action 605 and Action 705. For example, the third node 113 may be a gNB CU, the first node 111 may be a gNB DU, and the mobility trigger may be a LTM cell switch command.

[0268] Figure 12 is yet another signalling diagram illustrating another realization of the method for NW failures in which the first node 111 may be a NW entity that may prepare and / or send the signalling triggering mobility , according to Action 605 and Action 705, and may also be responsible for detecting the failure in the control plane in the NW, according to Action 604. In Figure 12, the second node 112, NW entity 1 , may run the control plane, which may fail. The first node 111 , NW entity 2, may monitor the state of the control plane to detect failures. Upon detection according to Action 604, the first node 111 , NW entity 2, may prepare / send to the wireless device 130 the signalling that may trigger mobility, according to Action 605 and Action 705. For example, the second node 112, NW entity 1 , may be a gNB CU, the first node 111 , NW entity 2, may be a gNB DU, and the mobility trigger may be a LTM cell switch command.

[0269] Figure 13 is a further signalling diagram illustrating another realization of the method for NW failures in which the third node 113 may be an auxiliary function that may be responsible for detecting failures of the control plane in the second node 112 according to Action 801. Upon detection, the third node 113 may, according to Action 802 and Action 603, notify the first node 111 , depicted as NW entity 2. The first node 111 , NW entity 2, may be responsible for preparing and / or sending to the wireless device 130 the signalling that may trigger mobility, according to Action 605 and Action 705. For example, the second node 112 may be a gNB CU, the first node 111 may be a gNB DU, and the mobility trigger may be a LTM cell switch command.

[0270] In one example, the same network entity may execute all parts of the method. For example, an integrated base station such as the network node 110, e.g., a gNB, may have some functionality to detect the failure of the control plane at the wireless device 130 and have some functionality to prepare and / or send the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHY layers and the radio unit. This is illustrated in Figure 15. Figure 15 is another signalling diagram illustrating another realization of the method for wireless device 130 failures in which the first node 111 may be a single entity in the NW, that may be responsible for detecting failures of the CP in the wireless device 130, according to Action 604, and triggering mobility of the wireless device 130 , according to Action 605 and Action 705.

[0271] In another example, one network entity such as the third node 113, e.g., a gNB CU, may have some functionality to detect the failure of the control plane at the wireless device 130 according to Action 801. Another network entity such as the first node 111 , e.g., a gNB DU, may have the necessary functionality to prepare and / or send, according to Action 605 and Action 705, the signalling to the wireless device 130 that may trigger the mobility, e.g., the MAC and PHY layers in a gNB DU. This is illustrated in Figure 16. Figure 16 is yet another signalling diagram illustrating another realization of the method for wireless device 130 failures in which different entities in the NW may be responsible for detecting failures of the CP in the wireless device 130 and for and triggering mobility of the wireless device 130.

[0272] As a summarized overview of the foregoing, embodiments herein may be understood to relate to a set of methods for assessing the availability of the control plane between the wireless device 130 and the NW. The assessment may be made by the NW and if the control plane is considered to be unavailable or broken, the NW may initiate or trigger a mobility procedure that may allow the wireless device 130 to change serving cells. Triggering of the mobility procedure may use signalling from a different layer than the control plane, e.g., a MAC CE such as in LTM.

[0273] Certain embodiments disclosed herein may provide one or more of the following technical advantage(s), which may be summarized as follows.

[0274] Embodiments herein may be understood to allow for early detection of unavailability in the control plane between the wireless device 130 and the NW and prevention of interruptions of the service or reductions and / or minimizations of the time the service may be interrupted. Shortening the service interruption time to a nearly-deterministic low value may be necessary for connectivity service providers in order to be able to deliver performance guarantees.

[0275] By leveraging signalling that may trigger mobility from a different layer, embodiments herein may be able to address failures affecting the CP.

[0276] By leveraging mobility procedures, embodiments herein may allow the NW to deal with CP connectivity problems, avoiding that the wireless device 130 is forced to declare RLF and perform cell search and RRC connection re-establishment procedures. In this way, a detected control plane issue may be addressed in 50-100 ms.

[0277] Figure 17 depicts an example of the arrangement that the first node 111 may comprise to perform the method actions described above in relation to Figure 6, and / or any of Figures 9-16. The first node 111 is for handling the unavailability of the first protocol layer. The first node 111 is configured to operate in the wireless communications network 100.

[0278] 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 node 111 and will thus not be repeated here. For example, the failure may be configured to be detected by means of keep-alive messaging, e.g., a watchdog.

[0279] The first node 111 is configured and / or operable to, e.g. by means of a processing circuitry 1701 within the first node 111 configured to, send the indication to the wireless device 130 configured to operate in the wireless communications network 100. The indication is configured to indicate to perform a reconfiguration. The indication is configured to be sent using signalling from a different layer than the first protocol layer between the second node 112 and the wireless device 130, wherein the unavailability is configured to have been detected.

[0280] In some embodiments, one or more of the following may apply: a) the first node 111 may be configured to be the same node as the second node 112, b) the first node 111 and the second node 112 may be configured to be comprised in the same network node 110, c) the second node 112 may be configured to manage the first node 111 , d) the first node 111 may be configured to be a distributed unit and the second node 112 is configured to be a centralized unit, e) the unavailability may be configured to be of the control plane, f) the indication may be configured to be a MAC IE, g) the indication may be configured to be a DCI, h) the indication may be configured to be the RRC reconfiguration message, i) the reconfiguration may be configured to be one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration may be configured to be used for changing beams, j) the RRC reconfiguration may be configured to be comprised in a mobility procedure, k) the mobility procedure may be configured to be one of: an inter-cell mobility and an intra-cell mobility, I) the unavailability may be configured to have been detected by one of: the wireless device 130, the first node 111 , the second node 112 and a third node 113, m) the unavailability may be configured to be the failure, and n) the different layer may be configured to be a MAC layer and the first protocol layer may be configured to be an RRC layer.

[0281] In some embodiments, the unavailability may be configured to be detected by one of the first node 111 , the second node 112 and the third node 113.

[0282] In some embodiments, the first node 111 may be configured and / or operable to, e.g. by means of the processing circuitry 1701 within the first node 111 configured to, determine the unavailability of the first protocol layer.

[0283] In some embodiments, the first node 111 may be further configured with the two following configurations.

[0284] In some embodiments, the first node 111 may be also configured and / or operable to, e.g. by means of the processing circuitry 1701 within the first node 111 configured to, send, to the wireless device 130, the first indication configured to request the first availability check of the first protocol layer.

[0285] In some embodiments, the first node 111 may be configured and / or operable to, e.g. by means of the processing circuitry 1701 within the first node 111 configured to, receive, from the wireless device 130, the second indication configured to indicate the second availability check of the first protocol layer. The determining of the unavailability may be configured to be based on one or more of the first indication and the second indication.

[0286] In some embodiments, one of the following may apply: a) the unavailability may be configured to be detected by a different node than the second node 112 configured to be running the first protocol layer wherein the unavailability may be configured to have been detected, and b) the unavailability may be configured to be detected by the second node 112 configured to be running the first protocol layer wherein the unavailability may be configured to have been detected.

[0287] In some embodiments, the first node 111 may be configured and / or operable to, e.g. by means of the processing circuitry 1701 within the first node 111 configured to, receive the third indication from the one of the wireless device 130, the second node 112 and the third node 113 being configured to have detected the unavailability. The third indication may be configured to indicate the detected unavailability. The determining of the unavailability may be configured to be based on the third indication configured to be received. The indication configured to be sent may be configured to be the fourth indication configured to be sent responsive to the third indication configured to be received.

[0288] In some embodiments, the third indication may be configured to be received using signalling from a different layer than the first layer of the first protocol layer between the second node 112 and the wireless device 130.

[0289] The embodiments herein in the first node 111 may be implemented through one or more processors, such as a processing circuitry 1701 in the first node 111 depicted in Figure 17, 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 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 node 111.

[0290] The processing circuitry 1701 may be configured to, or operable to, perform the method actions according to Figure 6, and / or any of Figures 9-16.

[0291] The first node 111 may further comprise a memory 1702 comprising one or more memory units. The memory 1702 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 node 111.

[0292] In some embodiments, the first node 111 may receive information from, e.g., the second node 112, the third node 113, the wireless device 130 or another structure in the wireless communications network 100, through a receiving port 1703. In some embodiments, the receiving port 1703 may be, for example, connected to one or more antennas in first node 111. In other embodiments, the first node 111 may receive information from another structure in the wireless communications network 100 through the receiving port 1703. Since the receiving port 1703 may be in communication with the processing circuitry 1701 , the receiving port 1703 may then send the received information to the processing circuitry 1701. The receiving port 1703 may also be configured to receive other information.

[0293] The processing circuitry 1701 in the first node 111 may be further configured to transmit or send information to e.g., the second node 112, the third node 113, the wireless device 130 or another structure in the wireless communications network 100, through a sending port 1704, which may be in communication with the processing circuitry 1701 , and the memory 1702.

[0294] Those skilled in the art will also appreciate that the processing circuitry 1701 described above may comprise a combination of analog and digital modules, 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 1701 , 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). Also, in some embodiments, the first node 111 may be configured to perform the actions of Figure 6, and / or any of Figures 9-16 with respective units that may be implemented as one or more applications running on one or more processors such as the processing circuitry 1701.

[0295] Thus, the methods according to the embodiments described herein for the first node 111 may be respectively implemented by means of a computer program 1705 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 1701 , cause the at least one processing circuitry 1701 to carry out the actions described herein, as performed by the first node 111. The computer program 1705 product may be stored on a computer-readable storage medium 1706. The computer-readable storage medium 1706, having stored there on the computer program 1705, may comprise instructions which, when executed on at least one processing circuitry 1701 , cause the at least one processing circuitry 1701 to carry out the actions described herein, as performed by the first node 111. In some embodiments, the computer-readable storage medium 1706 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 1705 product may be stored on a carrier containing the computer program 1705 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1706, as described above.

[0296] The first node 111 may comprise a communication interface configured to facilitate communications between the first node 111 and other nodes or devices, e.g., the second node 112, the third node 113, the wireless device 130 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.

[0297] In other embodiments, the first node 111 may also comprise a radio circuitry 1707, which may comprise e.g., the receiving port 1703 and the sending port 1704. The radio circuitry 1707 may be configured to set up and maintain at least a wireless connection with the second node 112, the third node 113, the wireless device 130 or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0298] Hence, embodiments herein also relate to the first node 111 comprising the processing circuitry 1701 and the memory 1702, said memory 1702 containing instructions executable by said processing circuitry 1701 , whereby the first node 111 is operative to perform the actions described herein in relation to the first node 111 , e.g., in Figure 6, and / or any of Figures 9-16.

[0299] Figure 18 depicts an example of the arrangement that the wireless device 130 may comprise to perform the method actions described above in relation to Figure 7 and / or any of Figures 9-16. The wireless device 130 is for handling the unavailability of the first protocol layer The wireless device 130 is configured to operate in the wireless communications network 100. 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 wireless device 130 and will thus not be repeated here. For example, the failure may be configured to be detected by means of keep-alive messaging, e.g., a watchdog.

[0300] The wireless device 130 is configured and / or operable to, e.g., by means of a processing circuitry 1801 within the wireless device 130 configured to, receive the indication, that is, the fourth indication, from the first node 111 configured to operate in the wireless communications network 100. The indication is configured to indicate to perform the reconfiguration. The indication is configured to be received using signalling from a different layer than the first protocol layer between the second node 112 and the wireless device 130, wherein the unavailability is configured to have been detected.

[0301] In some embodiments, one or more of the following may apply: a) the first node 111 may be configured to be the same node as the second node 112, b) the first node 111 and the second node 112 may be configured to be comprised in the same network node 110, c) the second node 112 may be configured to manage the first node 111 , d) the first node 111 may be configured to be a distributed unit and the second node 112 is configured to be a centralized unit, e) the unavailability may be configured to be of the control plane, f) the indication may be configured to be a MAC IE, g) the indication may be configured to be a DCI, h) the indication may be configured to be the RRC reconfiguration message, i) the reconfiguration may be configured to be one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration may be configured to be used for changing beams, j) the RRC reconfiguration may be configured to be comprised in a mobility procedure, k) the mobility procedure may be configured to be one of: an inter-cell mobility and an intra-cell mobility, I) the unavailability may be configured to have been detected by one of: the wireless device 130, the first node 111 , the second node 112 and a third node 113, m) the unavailability may be configured to be the failure, and n) the different layer may be configured to be a MAC layer and the first protocol layer may be configured to be an RRC layer.

[0302] In some embodiments, the wireless device 130 may be further configured with one or more of the two following configurations.

[0303] The wireless device 130 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the wireless device 130 configured to, receive the first indication configured to request the first availability check of the first protocol layer from one of: the first node 111 , the second node 112 and the third node 113.

[0304] The wireless device 130 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the wireless device 130 configured to, send the second indication configured to indicate the second availability check of the first protocol layer to the one of the first node 111 , the second node 112 and the third node 113.

[0305] In some embodiments, the unavailability may be configured to be detected by one of the first node 111 , the second node 112 and the third node 113.

[0306] In some embodiments, one of the following may apply: a) the unavailability may be configured to be detected by a different node than the second node 112 configured to be running the first protocol layer wherein the unavailability may be configured to have been detected, and b) the unavailability may be configured to be detected by the second node 112 configured to be running the first protocol layer wherein the unavailability may be configured to have been detected.

[0307] In some embodiments, the wireless device 130 may be further configured with the two following configurations.

[0308] The wireless device 130 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the wireless device 130 configured to, determine the unavailability of the first protocol layer.

[0309] The wireless device 130 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the wireless device 130 configured to, send the third indication to the first node 111. The third indication may be configured to indicate the unavailability configured to be determined. The indication configured to be received may be configured to be the fourth indication configured to be received responsive to the third indication configured to be sent.

[0310] In some embodiments, the third indication may be configured to be sent using signalling from a different layer than the first layer of the first protocol layer between the second node 112 and the wireless device 130.

[0311] The embodiments herein in the wireless device 130 may be implemented through one or more processors, such as a processing circuitry 1801 in the wireless device 130 depicted in Figure 18, 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 wireless device 130. 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 wireless device 130.

[0312] The processing circuitry 1801 may be configured to, or operable to, perform the method actions according to Figure 7 and / or any of Figures 9-16.

[0313] The wireless device 130 may further comprise a memory 1802 comprising one or more memory units. The memory 1802 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 wireless device 130.

[0314] In some embodiments, the wireless device 130 may receive information from, e.g., the first node 111 , the second node 112, the third node 113 and / or another structure in the wireless communications network 100, through a receiving port 1803. In some embodiments, the receiving port 1803 may be, for example, connected to one or more antennas in the wireless device 130. In other embodiments, the wireless device 130 may receive information from another structure in the wireless communications network 100 through the receiving port 1803. Since the receiving port 1803 may be in communication with the processing circuitry 1801 , the receiving port 1803 may then send the received information to the processing circuitry 1801. The receiving port 1803 may also be configured to receive other information.

[0315] The processing circuitry 1801 in the wireless device 130 may be further configured to transmit or send information to e.g., the first node 111 , the second node 112, the third node 113 and / or another structure in the wireless communications network 100, through a sending port 1804, which may be in communication with the processing circuitry 1801 , and the memory 1802.

[0316] Those skilled in the art will also appreciate that the processing circuitry 1801 described above may comprise a combination of analog and digital modules, 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 1801 , 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).

[0317] Also, in some embodiments, the wireless device 130 may be configured to perform the actions of Figure 7 and / or any of Figures 9-16 with respective units that may be implemented as one or more applications running on one or more processors such as the processing circuitry 1801.

[0318] Thus, the methods according to the embodiments described herein for the wireless device 130 may be respectively implemented by means of a computer program 1805 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 1801 , cause the at least one processing circuitry 1801 to carry out the actions described herein, as performed by the wireless device 130. The computer program 1805 product may be stored on a computer-readable storage medium 1806. The computer- readable storage medium 1806, having stored thereon the computer program 1805, may comprise instructions which, when executed on at least one processing circuitry 1801 , cause the at least one processing circuitry 1801 to carry out the actions described herein, as performed by the wireless device 130. In some embodiments, the computer-readable storage medium 1806 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 1805 product may be stored on a carrier containing the computer program 1805 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1806, as described above.

[0319] The wireless device 130 may comprise a communication interface configured to facilitate communications between the wireless device 130 and other nodes or devices, e.g., the first node 111 , the second node 112, the third node 113 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.

[0320] In other embodiments, the wireless device 130 may also comprise a radio circuitry 1807, which may comprise e.g., the receiving port 1803 and the sending port 1804. The radio circuitry 1807 may be configured to set up and maintain at least a wireless connection with the first node 111 , the second node 112, the third node 113 and / or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0321] Hence, embodiments herein also relate to the wireless device 130 comprising the processing circuitry 1801 and the memory 1802, said memory 1802 containing instructions executable by said processing circuitry 1801 , whereby the wireless device 130 is operative to perform the actions described herein in relation to the wireless device 130, e.g., in Figure 7 and / or any of Figures 9-16.

[0322] Figure 19 depicts an example of the arrangement that the third node 113 may comprise to perform the method actions described above in relation to Figure 8, and / or any of Figures 11 , Figure 13 and Figure 16. The third node 113 is for handling the unavailability of the first protocol layer. The third node 113 is configured to operate in the wireless communications network 100.

[0323] 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 third node 113 and will thus not be repeated here. For example, the failure may be configured to be detected by means of keep-alive messaging, e.g., a watchdog..

[0324] The third node 113 is configured and / or operable to, e.g., by means of a processing circuitry 1901 within the third node 113 configured to, determine the unavailability of the first protocol layer between the second node 112 and the wireless device 130 configured to operate in the wireless communications network 100.

[0325] The third node 113 is also configured and / or operable to, e.g., by means of the processing circuitry 1901 within the third node 113 configured to, send the third indication to the first node 111 configured to operate in the wireless communications network 100. The third indication is configured to indicate the unavailability configured to be detected.

[0326] In some embodiments, one or more of the following may apply: a) the first node 111 may be configured to be the same node as the second node 112, b) the first node 111 and the second node 112 may be configured to be comprised in the same network node 110, c) the second node 112 may be configured to manage the first node 111 , d) the first node 111 may be configured to be a distributed unit and the second node 112 is configured to be a centralized unit, e) the unavailability may be configured to be of the control plane, and f) the unavailability may be configured to be the failure.

[0327] In some embodiments, one of the following may apply: a) the third node 113 may be configured to be a different node than the second node 112 configured to be running the first protocol layer wherein the unavailability may be configured to have been detected, and b) the third node 113 may be configured to be the same node as the second node 112.

[0328] In some embodiments, the third indication may be configured to be sent using signalling from a different layer than the first layer of the first protocol layer between the second node 112 and the wireless device 130.

[0329] The embodiments herein in the third node 113 may be implemented through one or more processors, such as a processing circuitry 1901 in the third node 113 depicted in Figure 19, 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 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 node 113.

[0330] The processing circuitry 1901 may be configured to, or operable to, perform the method actions according to Figure 8, and / or any of Figures 11 , Figure 13 and Figure 16. The third node 113 may further comprise a memory 1902 comprising one or more memory units. The memory 1902 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 node 113.

[0331] In some embodiments, the third node 113 may receive information from, e.g., the wireless device 130, the first node 111 , the second node 112 and / or another structure in the wireless communications network 100, through a receiving port 1903. In some embodiments, the receiving port 1903 may be, for example, connected to one or more antennas in third node 113. In other embodiments, the third node 113 may receive information from another structure in the wireless communications network 100 through the receiving port 1903. Since the receiving port 1903 may be in communication with the processing circuitry 1901 , the receiving port 1903 may then send the received information to the processing circuitry 1901. The receiving port 1903 may also be configured to receive other information.

[0332] The processing circuitry 1901 in the third node 113 may be further configured to transmit or send information to e.g., the wireless device 130, the first node 111 , the second node 112 and / or another structure in the wireless communications network 100, through a sending port 1904, which may be in communication with the processing circuitry 1901 , and the memory 1902.

[0333] Those skilled in the art will also appreciate that the processing circuitry 1901 described above may comprise a combination of analog and digital modules, 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 1901 , 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).

[0334] Also, in some embodiments, the third node 113 may be configured to perform the actions of Figure 8, and / or any of Figures 11 , Figure 13 and Figure 16 with respective units that may be implemented as one or more applications running on one or more processors such as the processing circuitry 1901.

[0335] Thus, the methods according to the embodiments described herein for the third node 113 may be respectively implemented by means of a computer program 1905 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 1901 , cause the at least one processing circuitry 1901 to carry out the actions described herein, as performed by the third node 113. The computer program 1905 product may be stored on a computer-readable storage medium 1906. The computer-readable storage medium 1906, having stored thereon the computer program 1905, may comprise instructions which, when executed on at least one processing circuitry 1901 , cause the at least one processing circuitry 1901 to carry out the actions described herein, as performed by the third node 113. In some embodiments, the computer-readable storage medium 1906 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 1905 product may be stored on a carrier containing the computer program 1905 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1906, as described above.

[0336] The third node 113 may comprise a communication interface configured to facilitate communications between the third node 113 and other nodes or devices, e.g., the wireless device 130, the first node 111 , the second node 112 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.

[0337] In other embodiments, the third node 113 may also comprise a radio circuitry 1907, which may comprise e.g., the receiving port 1903 and the sending port 1904. The radio circuitry 1907 may be configured to set up and maintain at least a wireless connection with the wireless device 130, the first node 111 , the second node 112 and / or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0338] Hence, embodiments herein also relate to the third node 113 comprising the processing circuitry 1901 and the memory 1902, said memory 1902 containing instructions executable by said processing circuitry 1901 , whereby the third node 113 is operative to perform the actions described herein in relation to the third node 113, e.g., in Figure 8, and / or any of Figures 11 , Figure 13 and Figure 16.

[0339] When using the word "comprise" or “comprising”, it shall be interpreted as non- limiting, i.e. , meaning "consist at least of".

[0340] 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.

[0341] 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.

[0342] 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.

[0343] Any of the terms processor and circuitry may be understood herein as a hardware component.

[0344] 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.

[0345] 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.

[0346] REFERENCES

[0347] 1. 3GPP TS 38.300 version 18.1.0.

[0348] 2. 3GPP TS 38.331 version 18.1.0.

Claims

1. CLAIMS:

1. A computer-implemented method performed by a first node (111), the method being for handling an unavailability of a first protocol layer, the first node (111) operating in a wireless communications network (100), and the method comprising:- sending (605) an indication to a wireless device (130) operating in the wireless communications network (100), the indication indicating to perform a reconfiguration, wherein the indication is sent using signalling from a different layer than the first protocol layer between a second node (112) and the wireless device (130), wherein the unavailability has been detected.

2. The method according to claim 1, wherein one or more of:- the first node (111) is the same node as the second node (112),- the first node (111) and the second node (112) are comprised in a same network node (110),- the second node (112) manages the first node (111),- the first node (111 ) is a distributed unit and the second node (112) is a centralized unit,- the unavailability is of a control plane,- the indication is a Medium Access Control, MAC, Information Element, IE,- the indication is a Downlink Control Information, DCI,- the indication is a Radio Resource Control, RRC, reconfiguration message,- the reconfiguration is one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration is used for changing beams,- the RRC reconfiguration is comprised in a mobility procedure,- the mobility procedure is one of: an inter-cell mobility and an intra-cell mobility,- the unavailability has been detected by one of: the wireless device (130), the first node (111), the second node (112) and a third node (113),- the unavailability is a failure, and- the different layer is a MAC layer and the first protocol layer is an RRC layer.

3. The method according to claim 2, wherein the unavailability is detected by one of the first node (111), the second node (112) and the third node (113).

4. The method according to claim 3, wherein the method further comprises:determining (604) the unavailability of the first protocol layer.

5. The method according to claim 4, wherein the method further comprises one or more of:- sending (601), to the wireless device (130), a first indication requesting a first availability check of the first protocol layer, and- receiving (602), from the wireless device (130), a second indication indicating a second availability check of the first protocol layer, and wherein the determining (604) of the unavailability is based on one or more of the first indication and the second indication.

6. The method according to any of claims 3-4, wherein one of:- the unavailability is detected by a different node than the second node (112) running the first protocol layer wherein the unavailability has been detected, and- the unavailability is detected by the second node (112) running the first protocol layer wherein the unavailability has been detected.

7. The method according to claims 4 and 6, and wherein the method further comprises:- receiving (603) a third indication from the one of the wireless device (130), the second node (112) and the third node (113) having detected the unavailability, the third indication indicating the detected unavailability, wherein the determining (604) of the unavailability is based on the received third indication, and wherein the sent indication is a fourth indication sent responsive to the received third indication.

8. The method according to claim 7, wherein the third indication is received using signalling from a different layer than the first layer of the first protocol layer between the second node (112) and the wireless device (130).

9. A computer-implemented method performed by a wireless device (130), the method being for handling an unavailability of a first protocol layer, the wireless device (130) operating in a wireless communications network (100), and the method comprising:- receiving (705) an indication from a first node (111) operating in the wireless communications network (100), the indication indicating to perform a reconfiguration, wherein the indication is received using signalling from a different layer than the first protocol layer between a second node (112) and the wireless device (130), wherein the unavailability has been detected.

10. The method according to claim 9, wherein one or more of:- the first node (111) is the same node as the second node (112),- the first node (111) and the second node (112) are comprised in a same network node (110),- the second node (112) manages the first node (111),- the first node (111 ) is a distributed unit and the second node (112) is a centralized unit,- the unavailability is of a control plane,- the indication is a Medium Access Control, MAC, Information Element, IE,- the indication is a Downlink Control Information, DCI,- the indication is a Radio Resource Control, RRC, reconfiguration message,- the reconfiguration is one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration is used for changing beams,- the RRC reconfiguration is comprised in a mobility procedure,- the mobility procedure is one of: an inter-cell mobility and an intra-cell mobility,- the unavailability has been detected by one of: the wireless device (130), the first node (111), the second node (112) and a third node (113),- the unavailability is a failure, and- the different layer is a MAC layer and the first protocol layer is an RRC layer.

11. The method according to claim 10, wherein the method further comprises one or more of:- receiving (701) a first indication requesting a first availability check of the first protocol layer from one of: the first node (111), the second node (112) and the third node (113), and- sending (702) a second indication indicating a second availability check of the first protocol layer to the one of the first node (111), the second node (112) and the third node (113).

12. The method according to any of claims 10-11, wherein the unavailability is detected by one of the first node (111), the second node (112) and the third node (113).

13. The method according to claim 12, wherein one of:- the unavailability is detected by a different node than the second node (112) running the first protocol layer wherein the unavailability has been detected, andthe unavailability is detected by the second node (112) running the first protocol layer wherein the unavailability has been detected.

14. The method according to any of claims 9-11 , wherein the method further comprises:- determining (703) the unavailability of the first protocol layer, and- sending (704) a third indication to the first node (111), the third indication indicating the determined unavailability, and wherein the received indication is a fourth indication received responsive to the sent third indication.

15. The method according to claim 14, wherein the third indication is sent using signalling from a different layer than the first layer of the first protocol layer between the second node (112) and the wireless device (130).

16. A computer-implemented method performed by a third node (113), the method being for handling an unavailability of a first protocol layer, the third node (113) operating in a wireless communications network (100), and the method comprising:- determining (801) an unavailability of a first protocol layer between a second node (112) and a wireless device (130) operating in the wireless communications network (100), and- sending (802) a third indication to a first node (111) operating in the wireless communications network (100), the third indication indicating the detected unavailability.

17. The method according to claim 16, wherein one or more of:- the first node (111) is the same node as the second node (112),- the first node (111) and the second node (112) are comprised in a same network node (110),- the second node (112) manages the first node (111),- the first node (111 ) is a distributed unit and the second node (112) is a centralized unit,- the unavailability is of a control plane, and- the unavailability is a failure.

18. The method according to any of claims 16-17, wherein one of:- the third node (113) is a different node than the second node (112) running the first protocol layer wherein the unavailability has been detected, and- the third node (113) is the same node as the second node (112).

19. The method according to any of claims 16-18, wherein the third indication is sent using signalling from a different layer than the first layer of the first protocol layer between the second node (112) and the wireless device (130).

20. A first node (111), for handling an unavailability of a first protocol layer, the first node (111) being configured to operate in a wireless communications network (100), and the first node (111) being further configured to:- send an indication to a wireless device (130) configured to operate in the wireless communications network (100), the indication being configured to indicate to perform a reconfiguration, wherein the indication is configured to be sent using signalling from a different layer than the first protocol layer between a second node (112) and the wireless device (130), wherein the unavailability is configured to have been detected.21 . The first node (111) according to claim 20, wherein one or more of:- the first node (111) is configured to be the same node as the second node (112),- the first node (111) and the second node (112) are configured to be comprised in a same network node (110),- the second node (112) is configured to manage the first node (111),- the first node (111) is configured to be a distributed unit and the second node (112) is configured to be a centralized unit,- the unavailability is configured to be of a control plane,- the indication is configured to be a Medium Access Control, MAC, Information Element, IE,- the indication is configured to be a Downlink Control Information, DCI,- the indication is configured to be a Radio Resource Control, RRC, reconfiguration message,- the reconfiguration is configured to be one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration is configured to be used for changing beams,- the RRC reconfiguration is configured to be comprised in a mobility procedure,- the mobility procedure is configured to be one of: an inter-cell mobility and an intra-cell mobility,- the unavailability is configured to have been detected by one of: the wireless device (130), the first node (111), the second node (112) and a third node (113),the unavailability is configured to be a failure, and the different layer is configured to be a MAC layer and the first protocol layer is configured to be an RRC layer.

22. The first node (111) according to claim 21 , wherein the unavailability is configured to be detected by one of the first node (111), the second node (112) and the third node (113).

23. The first node (111) according to claim 22, wherein the first node (111) is further configured to:- determine (604) the unavailability of the first protocol layer.

24. The first node (111) according to claim 23, wherein the first node (111) is further configured to one or more of:- send, to the wireless device (130), a first indication configured to request a first availability check of the first protocol layer, and- receive, from the wireless device (130), a second indication configured to indicate a second availability check of the first protocol layer, and wherein the determining of the unavailability is configured to be based on one or more of the first indication and the second indication.

25. The first node (111) according to any of claims 22-23, wherein one of:- the unavailability is configured to be detected by a different node than the second node (112) configured to be running the first protocol layer wherein the unavailability is configured to have been detected, and- the unavailability is configured to be detected by the second node (112) configured to be running the first protocol layer wherein the unavailability is configured to have been detected.

26. The first node (111) according to claims 23 and 25, and wherein the first node (111) is further configured to:- receive (603) a third indication from the one of the wireless device (130), the second node (112) and the third node (113) being configured to have detected the unavailability, the third indication being configured to indicate the detected unavailability, wherein the determining of the unavailability is configured to be based on the third indication configured to be received, and wherein the indication configured to be sent is configured to be a fourth indication configured to be sent responsive to the third indication configured to be received.

27. The first node (111) according to claim 26, wherein the third indication is configured to be received using signalling from a different layer than the first layer of the first protocol layer between the second node (112) and the wireless device (130).

28. A wireless device (130), for handling an unavailability of a first protocol layer, the wireless device (130) being configured to operate in a wireless communications network (100), and the wireless device (130) being further configured to:- receive an indication from a first node (111) configured to operate in the wireless communications network (100), the indication being configured to indicate to perform a reconfiguration, wherein the indication is configured to be received using signalling from a different layer than the first protocol layer between a second node (112) and the wireless device (130), wherein the unavailability is configured to have been detected.

29. The wireless device (130) according to claim 28, wherein one or more of:- the first node (111) is configured to be the same node as the second node (112),- the first node (111) and the second node (112) are configured to be comprised in a same network node (110),- the second node (112) is configured to manage the first node (111),- the first node (111) is configured to be a distributed unit and the second node (112) is configured to be a centralized unit,- the unavailability is configured to be of a control plane,- the indication is configured to be a Medium Access Control, MAC, Information Element, IE,- the indication is configured to be a Downlink Control Information, DCI,- the indication is configured to be a Radio Resource Control, RRC, reconfiguration message,- the reconfiguration is configured to be one of: an RRC reconfiguration, a reconfiguration of a transmission configuration, and the reconfiguration of the transmission configuration, wherein the transmission configuration is configured to be used for changing beams,- the RRC reconfiguration is configured to be comprised in a mobility procedure,- the mobility procedure is configured to be one of: an inter-cell mobility and an intra-cell mobility,- the unavailability is configured to have been detected by one of: the wireless device (130), the first node (111), the second node (112) and a third node (113),- the unavailability is configured to be a failure, andthe different layer is configured to be a MAC layer and the first protocol layer is configured to be an RRC layer.

30. The wireless device (130) according to claim 29, wherein the wireless device (130) is further configured to one or more of:- receive a first indication configured to request a first availability check of the first protocol layer from one of: the first node (111), the second node (112) and the third node (113), and- send a second indication configured to indicate a second availability check of the first protocol layer to the one of the first node (111), the second node (112) and the third node (113).

31. The wireless device (130) according to any of claims 29-30, wherein the unavailability is configured to be detected by one of the first node (111), the second node (112) and the third node (113).

32. The wireless device (130) according to claim 31 , wherein one of:- the unavailability is configured to be detected by a different node than the second node (112) configured to be running the first protocol layer wherein the unavailability is configured to have been detected, and- the unavailability is configured to be detected by the second node (112) configured to be running the first protocol layer wherein the unavailability is configured to have been detected.

33. The wireless device (130) according to any of claims 28-30, wherein the wireless device (130) is further configured to:- determine the unavailability of the first protocol layer, and- send a third indication to the first node (111), the third indication being configured to indicate the unavailability configured to be determined, and wherein the indication configured to be received is configured to be a fourth indication configured to be received responsive to the third indication configured to be sent.

34. The wireless device (130) according to claim 33, wherein the third indication is configured to be sent using signalling from a different layer than the first layer of the first protocol layer between the second node (112) and the wireless device (130).

35. A third node (113), for handling an unavailability of a first protocol layer, the third node (113) being configured to operate in a wireless communications network (100), and the third node (113) being further configured to:- determine an unavailability of a first protocol layer between a second node (112) and a wireless device (130) configured to operate in the wireless communications network (100), and- send a third indication to a first node (111) configured to operate in the wireless communications network (100), the third indication being configured to indicate the unavailability configured to be detected.

36. The third node (113) according to claim 35, wherein one or more of:- the first node (111) is configured to be the same node as the second node (112),- the first node (111) and the second node (112) are configured to be comprised in a same network node (110),- the second node (112) is configured to manage the first node (111),- the first node (111) is configured to be a distributed unit and the second node (112) is configured to be a centralized unit,- the unavailability is configured to be of a control plane, and- the unavailability is configured to be a failure.

37. The third node (113) according to any of claims 35-36, wherein one of:- the third node (113) is configured to be a different node than the second node (112) configured to be running the first protocol layer wherein the unavailability is configured to have been detected, and- the third node (113) is configured to be the same node as the second node (112).

38. The third node (113) according to any of claims 35-37, wherein the third indication is configured to be sent using signalling from a different layer than the first layer of the first protocol layer between the second node (112) and the wireless device (130).

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