Wireless device, first network node and methods performed thereby, for handling an inability of the wireless device to comply with a control plane procedure with the first network node

Abstract

A computer-implemented method performed by a wireless device (130). The method is for handling an inability of the wireless device (130) to comply with a control plane procedure with a first network node (111). The wireless device (130) operates in a wireless communications network (100). The wireless device (130) determines (405) the inability to comply with the control plane procedure. The wireless device (130) also initiates (406) a Radio Resource Control (RRC) reconfiguration at the wireless device (130). The initiating (406) is performed after the wireless device (130) has determined the inability to comply with the control plane procedure, and before a protocol layer of a user plane between the first network node (111) and the wireless device (130) has become unreliable.

Description

[0001] WIRELESS DEVICE, FIRST NETWORK NODE AND METHODS PERFORMED THEREBY, FOR HANDLING AN INABILITY OF THE WIRELESS DEVICE TO COMPLY WITH A CONTROL PLANE PROCEDURE WITH THE FIRST NETWORK NODE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to a first node and methods performed thereby for handling an inability to comply with a control plane procedure with a first network node. The present disclosure also relates generally to the first network node, and methods performed thereby for handling the inability of the wireless device to comply with the control plane procedure with the first network node.

[0004] BACKGROUND

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

[0006] The wireless communications network covers a geographical area which may be divided into cell areas, each cell area being served by a network node, which may be an access node such as a radio network node, radio node or a base station, 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.

[0007] 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.

[0008] Handover and random access

[0009] 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.

[0010] 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.

[0011] In this basic procedure, the gNB may be in control of all aspects of the handover.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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).

[0019] 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.

[0020] 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.

[0021] Delivery of connectivity services with reliability, availability and resilience

[0022] 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.

[0023] 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.

[0024] 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.

[0025] Radio Link Failure

[0026] 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.

[0027] 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.

[0028] 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 (Rll), distributed unit (DU), or centralized unit (CU).

[0029] In spite of the different root causes, in most situations, the UE may declare RLF due to these issues.

[0030] Inability to comply with RRCReconfiguration

[0031] 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.

[0032] 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”.

[0033] 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.

[0034] 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. 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.

[0035] 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.

[0036] RRC connection re-establishment

[0037] 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.

[0038] 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.

[0039] 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-RLC0 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'.

[0040] 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 in 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.

[0041] 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.

[0042] SUMMARY

[0043] As part of the development of embodiments herein, one or more challenges with the existing technology will first be identified and discussed.

[0044] The existing conditional mobility procedures may be triggered by conditions related to the power received from the serving gNB and alternative gNBs, e.g., events A3, A4 and A5. These conditions may be observed by performing measurements on transmitted signals. As such, they may be understood to be indicative of whether the gNB may be transmitting these signals but, by themselves, may not provide any information on whether the gNB, including the control plane functionality, may be operating correctly.

[0045] If an issue affects the control plane between the UE and the NW, the User Plane (UP) connection may or may not be simultaneously affected. For some implementations, the user plane may continue operating normally for some time. However, at some point, it may be interrupted as well, for example, due to a failure in mobility, a missing but necessary reconfiguration, etc. In such cases, the UE may not be aware of the CP failure until it is too late and it affects the UP as well. At that point, the UE may trigger Radio Link Failure (RLF) and initiate RRC connection re-establishment. Similarly, if the UE is unable to comply with an RRC reconfiguration, it will initiate RRC connection re-establishment. Radio link failure and initiating RRC connection re-establishment may be understood to be processes that may typically result in long interruption times for the services that may rely on the radio connectivity.

[0046] According to the foregoing, it is an object of embodiments herein to improve the handling an inability of a wireless device to comply with a control plane procedure with a first network node.

[0047] According to a first aspect of embodiments herein, the object is achieved by a computer- implemented method, performed by a wireless device. The method is for handling an inability of the wireless device to comply with a control plane procedure with a first network node. The wireless device operates in a wireless communications network. The wireless device determines the inability to comply with the control plane procedure. The wireless device initiates a Radio Resource Control (RRC) reconfiguration at the wireless device. The initiating is performed after the wireless device has determined the inability to comply with the control plane procedure, and before a protocol layer of a user plane between the first network node and the wireless device has become unreliable.

[0048] According to a second aspect of embodiments herein, the object is achieved by a computer-implemented method, performed by the first network node. The method is for handling the inability of the wireless device to comply with the control plane procedure with the first network node. The first network node operates in the wireless communications network. The first network node sends a fourth indication to the wireless device. The fourth indication indicates a detected unavailability of the first protocol layer of the control plane. The sending is performed before the protocol layer of the user plane between the first network node and the wireless device has become unreliable.

[0049] According to a third aspect of embodiments herein, the object is achieved by a the wireless device. The wireless device is for handling the inability of the wireless device to comply with the control plane procedure with the first network node. The wireless device is configured to operate in the wireless communications network. The wireless device is configured to determine the inability to comply with the control plane procedure. The wireless device is also configured to initiate the RRC reconfiguration at the wireless device. The initiating is configured to be performed after the wireless device has determined the inability to comply with the control plane procedure, and before the protocol layer of the user plane between the first network node and the wireless device has become unreliable. According to a fourth aspect of embodiments herein, the object is achieved by the first network node. The first network node is for handling the inability of the wireless device to comply with the control plane procedure with the first network node. The first network node is configured to operate in the wireless communications network. The first network node is configured to send the fourth indication to the wireless device. The fourth indication is configured to indicate the detected unavailability of the first protocol layer of the control plane. The sending is configured to be performed before the protocol layer of the user plane between the first network node and the wireless device has become unreliable.

[0050] By determining the inability to comply with the control plane procedure, the wireless device may allow for early detection of the inability to comply with the control plane procedure. The wireless device may then be enabled to take appropriate remedial action.

[0051] Differently from current specifications, by initiating the RRC reconfiguration, the wireless device may allow for early detection of failures in the control plane between the wireless device and the NW, e.g., the first network node, and prevention of interruptions of the service or reductions and / or minimizations of the time the service may be interrupted. Shortening the maximum 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.

[0052] By leveraging mobility procedures, embodiments herein may allow the wireless device to deal with control plane connectivity problems in a faster way than by following some or all of the steps of: declaration of radio Link failure, which may typically take ~2 seconds, performing cell search, which may take multiple seconds, RRC connection re-establishment, which may take 100s of milliseconds.

[0053] In this way, a detected control plane issue may be addressed in 50-100 ms, which may be tolerated by many applications.

[0054] By sending the fourth indication indicating the detected unavailability of the first protocol layer of the control plane to the wireless device, before the protocol layer of the user plane has become unreliable, the first network node may enable the early detection of the unavailability and that the wireless device may in turn determine early the inability to comply with the control plane procedure and may start service recovery before the degradation may affect user plane and service quality.

[0055] The concept of indirectly triggering a connection re-establishment to recover radio problems may be understood to be known in 3GPP. For example, a UE may declare RLF after loss of radio synchronization. Conditional handover may be another such procedure, where certain radio conditions or user plane issues may trigger mobility. However, these types of procedures may be understood to be slow because they require time for detecting the degraded radio conditions or user plane degradation. In other words, service recovery is only started after the service has been degraded, while embodiments herein may enable to start service recovery before the degradation may affect user plane and service quality, providing a technical advantage over existing methods.

[0056] BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Examples of embodiments herein are described in more detail with reference to the accompanying drawings, according to the following description.

[0058] Figure 1 is a signalling diagram depicting basic operations and signalling in conditional handover, according to existing methods.

[0059] 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.

[0060] Figure 3 is a schematic diagram depicting an example of a wireless communications network, according to embodiments herein.

[0061] Figure 4 is a flowchart depicting a method in a wireless device, according to embodiments herein.

[0062] Figure 5 is a flowchart depicting a method in a first network node, according to embodiments herein.

[0063] Figure 6 is a signalling diagram depicting a non-limiting example of methods performed by the wireless device and the first network node, according to embodiments herein.

[0064] Figure 7 is a signalling diagram depicting another non-limiting example of methods performed by the wireless device and the first network node, according to embodiments herein.

[0065] Figure 8 is a signalling diagram depicting yet another non-limiting example of methods performed by the wireless device and the first network node, according to embodiments herein.

[0066] Figure 9 is a signalling diagram depicting a further non-limiting example of methods performed by the wireless device and the first network node, according to embodiments herein.

[0067] Figure 10 is a signalling diagram depicting another non-limiting example of methods performed by the wireless device and the first network node, according to embodiments herein.

[0068] Figure 11 is a signalling diagram depicting a procedure for UE-triggered connection reestablishment following control plane issues, according to existing methods.

[0069] Figure 12 is a signalling diagram depicting a non-limiting example of a method according to embodiments herein.

[0070] Figure 13 is a schematic block diagram illustrating an embodiments of a wireless device, according to embodiments herein.

[0071] Figure 14 is a schematic block diagram illustrating an embodiments of a first network node, according to embodiments herein. DETAILED DESCRIPTION

[0072] 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 relate to a method in a wireless device, e.g., a UE, for detecting a failure and autonomously triggering mobility. Particularly, embodiments herein may relate to methods for assessing the health of the control plane between the wireless device and the NW and how they may be used to trigger mobility-based service recovery procedures initiated by the wireless device. Embodiments herein may include variations in which either a wireless device or a network node, e.g., a gNB, may assess whether the control plane logic and protocol between the network node and the wireless device may be operating correctly.

[0073] If the control plane is considered to be unavailable, the wireless device may initiate a mobility procedure that, for example, may allow the wireless device to change serving cells.

[0074] There may be understood to be three groups of embodiments: mobility triggered by the wireless device, with CP availability assessment performed by the wireless device, mobility triggered by the wireless device with CP availability assessment performed by the NW, and mobility triggered by the wireless device following failure to comply with a configuration provisioned by the network node.

[0075] 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.

[0076] Figure 3 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.

[0077] The wireless communications network 100 may comprise a plurality of network nodes, whereof a first network node 111 and a second network node 112 are depicted in the nonlimiting example of Figure 3. Any of the first network node 111 and the second network node 112 may be a radio network node. That is, a transmission point such as a radio base station, for example a gNB, or any other network node with similar features capable of serving a user equipment, such as a wireless device, in the wireless communications network 100. In some examples, such as that depicted in Figure 3b), any of the first network node 111 and the second network node 112 may be a distributed node, and may partially perform its functions in collaboration with a virtual node 113 in a cloud 115. Any of the first network node 111 and the second network node 112 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.

[0078] In some examples, the wireless communications network 100 may include an access network, such as a radio access network (RAN), and a core network, which may include one or more core network nodes. The access network may include one or more access network nodes, such as any of the first network node 111 , the second network node 112 and the virtual node 113, e.g., which may be generally referred to as network nodes, or any other similar 3rd Generation Partnership Project (3GPP) access nodes or non-3GPP access points. Moreover, as will be appreciated by those of skill in the art, a network node may not necessarily be limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it may be understood that network nodes may include disaggregated implementations or portions thereof. For example, in some embodiments, the wireless communications network 100 may include one or more Open-RAN (ORAN) network nodes. Any of the first network node 111 and the second network node 112 may be ORAN network nodes. An ORAN network node may be understood to be a node in the wireless communications network 100 that may support an ORAN specification, e.g., a specification published by the O-RAN Alliance, or any similar organization, and may operate alone or together with other nodes to implement one or more functionalities of any node in the wireless communications network 100, including one or more network nodes and / or core network nodes.

[0079] Examples of an ORAN network node may include an open radio unit (0-Rll), an open distributed unit (0-Dll), an open central unit (O-CU), including an O-CU control plane (O-CU- CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller, near-real time or non-real time, hosting software or software plug-ins, such as a near-real time control application, e.g., xApp, or a non-real time control application, e.g., rApp, or any combination thereof, the adjective “open” designating support of an ORAN specification. Any of the first network node 111 , the second network node 112 and the virtual node 113 may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an A1 , F1 , W1, E1, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may be implemented in a virtualization environment, in which one or more network functions may be virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an O-2 interface defined by the O- RAN Alliance or comparable technologies.

[0080] The wireless communications network 100 may cover a geographical area, which in some embodiments may be divided into cell areas, wherein each cell area may be served by a radio network node, although, one radio network node may serve one or several cells. In the example of Figure 1 , the first network node 111 serves a first cell 121 and the second network node 112 serves a second cell 122. This may be understood to be for illustrative purposes only. Any of the first network node 111 and the second network node 112 may serve one or more additional cells. Any of the first network node 111 , the second network node 112 and the virtual node 113 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, any of the first network node 111 , the second network node 112 and the virtual node 113 may serve receiving nodes with serving beams. Any of the first network node 111 , the second network node 112 and the virtual node 113 may support one or several communication technologies, and its name may depend on the technology and terminology used.

[0081] The first network node 111 may be a source network node and to the second network node 112 may be a target network node.

[0082] The first network node 111 may be a neighbor network node to the second network node 112.

[0083] 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 3. 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.

[0084] The first network node 111 may be configured to communicate with the second network node 112 over a first link 141 , e.g., a wired link. The wireless device 130 may be configured to communicate with the first network node 111 over a second link 142, e.g., a wired link. The first network node 111 may be configured to communicate with the third node 113 over a third link 143, e.g., a wired link.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] Some embodiments herein will now be further described with some non-limiting examples, which may be combined with the embodiments just described.

[0090] Embodiments of a computer-implemented method, performed by the wireless device 130, will now be described with reference to the flowchart depicted in Figure 4. The method is for handling an inability of the wireless device 130 to comply with a control plane procedure with the first network node 111. The wireless device 130 operates in the wireless communications network 100.

[0091] In some embodiments, the wireless communications network 100 may be a 5G network.

[0092] This disclosure is largely presented for the case that control plane may be understood to refer to the functionality provided by the RRC layer. However, the principle may be understood to be applicable to other types of control plane.

[0093] The control plane procedure may be understood as a series of actions that may be performed executed by a wireless device, here, the wireless device 130, and / or the network, here, the first network node 111 , for the purpose of controlling some aspects of the radio communication between the wireless device, here, the wireless device 130 and the network, here, the first network node 111.

[0094] Several embodiments are comprised herein. The method may comprise one or more of the other actions described next in relation to Figure 4. In some embodiments, all the actions may be performed. In particular embodiments, Action 405 and Action 406 are performed.

[0095] 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 wireless device 130 is depicted in Figure 4. In Figure 4 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 4.

[0096] Embodiments herein may comprise a set of methods and signaling that may be taken into account, together with other conditions, e.g., radio measurements, to define an Event that may be used to trigger mobility, e.g., hand over, of the wireless device 130 for the purpose of resilience, that is, to release connectivity from a malfunctioning part of the system and to connect to a functional one. In all the methods described herein, mobility may be initiated by the wireless device 130.

[0097] Action 401

[0098] In some embodiments, the method may comprise one or more of Action 401 , Action 402 and Action 404. Any of Action 401 and Action 402 may be understood to correspond to a CP availability check protocol, which may be comprised in some examples of embodiments herein.

[0099] According to embodiments herein, the wireless device 130 and / or the first network node 111 may optionally perform a CP availability check protocol. 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 first network 111. Such signals may be unidirectional (1-way) or bidirectional (2 -ways).

[0100] For bidirectional availability messages, according to the CP availability check protocol, the wireless device 130 may send a first “availability check” message to the first network node 111 , which in turn may process the message and may send a second “availability check” message to the wireless device 130, as will be described in Action 402.

[0101] In this Action 401 , the wireless device 130 may send, to the first network node 111 , a first indication requesting a first availability check of the first protocol layer of the control plane.

[0102] The first indication may be understood in some examples, as a first availability check message.

[0103] By sending the first indication in this Action 401 , the wireless device 130 may then be enabled to receive in the next Action 402, or not, a second indication from the first network node 111 in response, and thereby be enabled to determine, in Action 404, 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 in the next Action 402, or by a failure to receive the response within a certain time window, as will be described in Action 404.

[0104] Further details of the first indication are provided in the description of Action 402.

[0105] Some related concepts are available in existing methods and specifications. The concept of periodically verifying the availability of a communication channel, sometimes referred to as watchdog, may be understood to be known, for example, in the context of industrial networks. However, according to embodiments herein, availability checks may be performed on the control plane of the communication channel, instead of using the user plane as commonly done with a watchdog. This may be understood to provide a technical advantage by allowing early detection of control plane procedures, before they may potentially affect the user plane.

[0106] Action 402

[0107] In some embodiments, in this Action 402, the wireless device 130 may obtain, from the first network node 111 , a second indication indicating a second availability check of the first protocol layer of the control plane.

[0108] The second indication may be understood in some examples, as another, e.g., a second, availability check message.

[0109] For unidirectional availability messages according to the CP availability check protocol, the first network node 111 may deliver an “availability check” message, which may be received by the wireless device 130 in this Action 402.

[0110] For bidirectional availability messages according to the CP availability check protocol, the wireless device 130 may have sent a first “availability check” message to the first network node 111 in Action 401 , which in turn may process the message and may send a second “availability check” message to the wireless device 130 in this Action 402.

[0111] In one example, the “availability check” messages, that is, any of the first indication of Action 401 and the second indication of this Action 402, 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.

[0112] In one example, the first network node 111 or the wireless device 130, 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. In one example, the first network node 111 or the wireless device 130, 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.

[0113] In one example, the first network node 111 or the wireless device 130, 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, the wireless device 130 may have a timer that may be reset every time that the wireless device 130 may receive a message from B the first network node 111. If the timer expires, the wireless device 130 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.

[0114] The time T may be configured by the network, for example, by the first network 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).

[0115] In one example, other messages, e.g., CP RRC messages 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 CP signalling when other messaging may be anyway ongoing without issues. 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 plane message, any message originating from a CU, any user plane message, any message originating from a DU; etc.

[0116] 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.

[0117] By receiving, or not, the second indication in this Action 402, the wireless device 130 may then be enabled to determine, in Action 404, 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 described later.

[0118] As stated earlier, according to embodiments herein, availability checks may be performed on the control plane of the communication channel, instead of using the user plane as commonly done with a watchdog. This may be understood to provide a technical advantage by allowing early detection of control plane procedures, before they may potentially affect the user plane.

[0119] Action 403

[0120] In this Action 403, the wireless device 130 may obtain, from the first network node 111, a third indication indicating to perform an RRC reconfiguration, which is referred to herein as “another” RRC reconfiguration. The third indication may be an RRCReconfiguration message.

[0121] By receiving the third indication in this Action 403, the wireless device 130 may then be enabled to determine, in Action 404, 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 first network node 111. The wireless device 130 may then be enabled to take appropriate remedial action.

[0122] Action 404

[0123] Optionally, if the first network node 111 detects CP unavailability, the first network node 111 may inform the wireless device 130 about it.

[0124] In this Action 404, the wireless device 130 may obtain a fourth indication from the first network node 111. The fourth indication may indicate a detected unavailability of the first protocol layer of the control plane.

[0125] Conditions for the first network node 111 to declare CP availability issues

[0126] This section may be understood to apply only to the bidirectional protocol case.

[0127] The first network node 111 , if it may be expecting an “availability check” message, which may be sent according to Action 401, may use a timer to declare CP unavailability. The timer counter may be reset by receiving an expected “availability check” message from the wireless device 130, which may be sent according to Action 401 , and if the content of such message is considered valid.

[0128] In the unidirectional signaling protocol, the first network node 111 may expect to receive “availability check” messages, which may be sent according to Action 401 , with a certain periodicity, and may declare CP as having problems if a certain number of valid “availability check” messages, 1 or more, are not received within a certain configurable time period.

[0129] Regarding the first network node 111 signaling CP issues to the wireless device 130, it may be problematic for the first network node 111 to signal CP issues to the wireless device 130, hence the importance of enabling the wireless device 130 to autonomously check CP availability. However, there may be cases where such signaling may be possible, for example if the CP that may be being monitored and potentially unavailable is at RRC level, and the CP used for signaling RRC issues is at a lower level, e.g., a MAC CE.

[0130] By determining the unavailability of the first protocol layer in this Action 404, the wireless device 130 may allow for early detection of unavailability in the first protocol layer between the wireless device 130 and the first network node 111. The wireless device 130 may then be enabled to take appropriate remedial action in Action 405.

[0131] Differently from current specifications, embodiments herein may allow for early detection of failures in the control plane between the wireless device 130 and the NW, e.g., the first network node 111 , 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.

[0132] Action 405

[0133] In this Action 405, the wireless device 130 determines the inability to comply with the control plane procedure.

[0134] Determining may be understood as calculating, detecting, deriving or obtaining a confirmation.

[0135] According to one option, the inability may have been detected by one of: the wireless device 130 and the first network node 111.

[0136] According to another option, the inability may be due to an unavailability of a first protocol layer of the control plane with the first network node 111. The protocol layer of the user plane may be a second protocol layer.

[0137] Conditions for the wireless device 130 to declare CP availability issues

[0138] In some embodiments, the inability may comprise an inability to perform the another RRC reconfiguration received from the first network node 111 in Action 403.

[0139] In some embodiments, the determining in this Action 405 of the inability may be based on one of the first indication and the second indication.

[0140] In some examples, the wireless device 130 may detect CP availability issues, using a unidirectional protocol.

[0141] The wireless device 130 may perform an integrity check based on received CP messages according to Action 402. If any of the conditions described in Conditions for the UE to declare CP availability issues are fulfilled, the wireless device 130 may consider CP as unavailable. If the additional optional conditions associated to a mobility event are also fulfilled, the wireless device 130 may start a mobility procedure in Action 406 as described later. CP provisioning problems

[0142] As described in the section entitled “RRC connection re-establishment”, in 5G NR, when a wireless device 130 cannot comply with a configuration provided by the NW, e.g., by the first network node 111 , e.g., an RRCReconfiguration message, it may initiate RRC connection reestablishment.

[0143] In the procedures of the third group, the wireless device 130 may trigger a mobility procedure when it may determine that it is unable to comply with a configuration provided by the NW, e.g., the first network node 111 , e.g., an RRCReconfiguration message. This is illustrated later in Figure 6.

[0144] In some embodiments, the determining in this Action 405 may be based on one or more of the following options.

[0145] According to a first option, the determining in this Action 405 may be based on a failure of a verification. This may be for example, the failure to verify the integrity of the message and / or that the function that generated the message content may be functional, the failure to verify with high confidence if the CP protocol operates correctly by performing the integrity check based on the content and encoding defined above, or similar.

[0146] According to a second option, the determining in this Action 405 may be based on a time elapsed since when a last second indication was obtained from the first network node 111. The wireless device 130, if it may be expecting an “availability check” message may use a timer to declare CP unavailability. If the wireless device 130 may not receive a CP availability check message for T seconds, the wireless device 130 may determine the inability to comply with the control plane procedure in this Action 405 and may trigger mobility, according to Action 406, as described later.

[0147] The timer counter may be reset by receiving an expected “availability check” message from the first network node 111 according to Action 402, and if the content of such message is considered valid, see section on the signaling protocol.

[0148] According to a third option, the determining in this Action 405 may be based on an insufficient number of second indications were obtained from the first network node 111 within a first time period.

[0149] In the unidirectional signaling protocol, the wireless device 130 may expect to receive “availability check” messages according to Action 402 with a certain periodicity, and may declare CP as unavailable if a certain number of “availability check” messages, one or more, may be not received within a certain configurable time period or if they are invalid.

[0150] In the bidirectional signaling protocol, the wireless device 130 may expect to receive a second “availability check” message according to Action 402 within a certain delay, following a first “availability check” message sent to the first network node 111 according to Action 401 , and may declare CP as unavailable if a certain number of second “availability check” messages, one or more, may be not received within a certain configurable time period following the transmission of the first “availability check” message or if they are invalid. For example, the wireless device 130 may initiate a timer, e.g., a countdown, when generating the first message; or when passing it to a lower layer for transmission; or when transmitting it to the first network node 111 according to Action 401. If the timer expires before a valid second message is received, the wireless device 130 may declare the CP unavailable.

[0151] In some embodiments, one or more of the following options may apply. According to a first option, the unavailability of the first protocol layer of the control plane may be a condition for triggering mobility.

[0152] According to a second option, unreliable may indicate that radio link failure may have to be declared by the wireless device 130.

[0153] In some embodiments, the condition for triggering mobility may be a failure in a CRC check in the obtained second indication.

[0154] In an example, the wireless device 130 may not receive a second valid CP availability check message in Action 402 for T seconds after transmission of the first message in Action 401 , and may trigger mobility in Action 406, as will be described later.

[0155] In an example, the wireless device 130 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.

[0156] The wireless device 130 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.

[0157] In an example approach, the wireless device 130 may transmit a first challenge message to the first network node 111 in Action 401 , which may detect issues in the message integrity and report it to the wireless device 130 in Action 404, which may trigger the mobility procedure in Action 406, as will be described later.

[0158] By determining the inability to comply with the control plane procedure in this Action 405, the wireless device 130 may allow for early detection of the inability to comply with the control plane procedure. The wireless device 130 may then be enabled to take appropriate remedial action in Action 406.

[0159] As stated earlier, differently from current specifications, embodiments herein may allow for early detection of failures in the control plane between the wireless device 130 and the NW, e.g., the first network node 111 , 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. Action 406

[0160] In this Action 406, the wireless device 130 initiates a Radio Resource Control (RRC) reconfiguration at the wireless device 130. The initiating in this Action 406 is performed after the wireless device 130 has determined the inability to comply with the control plane procedure, and before a protocol layer of a user plane between the first network node 111 and the wireless device 130 has become unreliable.

[0161] Initiating may be understood as starting, triggering, or enabling.

[0162] In some embodiments, one or more of the following may apply. According to one option, the RRC reconfiguration may be comprised in a mobility procedure.

[0163] Mobility procedure

[0164] In the context of this disclosure, initiating or triggering a mobility procedure by the wireless device 130 may refer to applying a configuration, e.g., that may be understood to be part of a mobility procedure, that may be stored, or pre-configured, in the wireless device 130. For example, the NW, e.g., the first network node 111 , may provide a configuration, e.g., in an RRCReconfiguration message, that may be applied by the wireless device 130 only when the trigger condition may occur.

[0165] Embodiments herein may be understood to only describe mobility trigger conditions related to control plane (CP) availability. It may be understood that the actual mobility trigger Event may be subject to additional trigger conditions that may be related, e.g., to radio measurements, which are not further discussed here.

[0166] Alternatives to the mobility procedure

[0167] The principle of embodiments herein may be applied to other connectivity management functions than mobility. For example, the method in embodiments herein may be used to trigger a procedure for re-attaching or re-connecting to the wireless communications network 100 or to disconnect from the wireless communications network 100.

[0168] In some embodiments, multiple options may be possible based on some ordering. For example, upon detecting CP unavailability, the wireless device 130 may attempt to start a mobility procedure. If not possible or not successful, the wireless device 130 may attempt a second procedure, e.g., a re-connection or re-attachment, etc.

[0169] According to another option, the inability may have been detected by one of: the wireless device 130 and the first network node 111.

[0170] If the wireless device 130 detects CP unavailability or CP provisioning problems according to Action 405, or if CP unavailability is signaled by the first network node 111 according to Action 404, and if additional potential conditions are fulfilled, the wireless device 130 may start a mobility procedure. Optionally, the wireless device 130 may inform the first network node 111 that it may perform a mobility procedure due to CP provisioning problems. In one example approach, the wireless device 130 may transmit a first challenge message to the first network node 111 in Action 401 and, based on the response received from the NW in Action 402, the wireless device 130 may trigger the mobility procedure in this Action 406. In this example, the second message may not be received correctly according to Action 402, and a new valid second message may be not received by the wireless device 130 within T seconds from the first message transmission in Action 401 , hence the mobility procedure may be triggered this Action 406.

[0171] According to yet another option, the inability may be due to an unavailability of a first protocol layer of the control plane with the first network node 111. The protocol layer of the user plane may be a second protocol layer.

[0172] By initiating the RRC reconfiguration in this Action 405, the wireless device 130 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.

[0173] By leveraging mobility procedures, embodiments herein may allow the wireless device 130 to deal with control plane connectivity problems in a faster way than by following some or all of the steps of: declaration of radio Link failure, which may typically take ~2 seconds, performing cell search, which may take multiple seconds, RRC connection re-establishment, which may take 100s of milliseconds.

[0174] In this way, a detected control plane issue may be addressed in 50-100 ms, which may be tolerated by many applications.

[0175] The concept of indirectly triggering a connection re-establishment to recover radio problems may be understood to be known in 3GPP. For example, a UE may declare RLF after loss of radio synchronization. Conditional handover may be another such procedure, where certain radio conditions or user plane issues may trigger mobility. However, these types of procedures may be understood to be slow because they require time for detecting the degraded radio conditions or user plane degradation. In other words, service recovery is only started after the service has been degraded, while embodiments herein may enable to start service recovery before the degradation may affect user plane and service quality, providing a technical advantage over existing methods.

[0176] Action 407

[0177] In this Action 407, the wireless device 130 may send a fifth indication to the second network node 112. The fifth indication may indicate the determined inability.

[0178] The fifth indication may be a RRCReconfigurationComplete message. In one example, the wireless device 130 may, in this Action 407, indicate to the NW, e.g., the second network node 112, that the mobility procedure was initiated due to the inability to comply with the provided configuration. That is, in some examples, the fifth indication, e.g., the RRCReconfigurationComplete message, signalling the completion of the mobility procedure may also carry an indication that the mobility procedure was initiated due to the inability to comply with the provided configuration.

[0179] For example, this information may be indicated implicitly as a field in a message, e.g., a message that may be sent to the NW, e.g., the second network node 112, as part of the mobility procedure, such as an RRCReconfigurationComplete message, or explicitly, e.g., by using a specific sequence or resource for transmission of a (random) access signal. This is illustrated in Figure 7. The wireless device 130 may receive an RRCReconfiguration from the source first network node 111 in Action 403. It may attempt to apply the configuration carried by the received message but it may be unable. Consequently, it may trigger a mobility procedure that may take the wireless device 130 to change to a new serving network node, e.g., a target gNB, such as the second network node 112. As part of the mobility procedure, the wireless device 130 may send an RRCReconfigurationCompletef) message to the second network node 112. The message may indicate to the NW that the mobility procedure was initiated due to the inability to comply with the RRCReconfiguration from the source first network node 111 , e.g., received in Action 403. Note that the RRCReconfigurationCompletef) message may not indicate the completion of the RRCReconfiguration provided by the source first network node 111 , rather it may indicate that at least a part of the mobility procedure, which may typically involve different RRCReconfiguration message, has been completed.

[0180] Example implementations of embodiments herein are provided later in this document.

[0181] All the procedures described herein may be specified by means of defining new triggers for conditional handover.

[0182] Embodiments of a computer-implemented method performed by the first network node 111 , will now be described with reference to the flowchart depicted in Figure 5. The method is for handling the inability of the wireless device 130 to comply with the control plane procedure with the first network node 111. The first network node 111 operates in the wireless communications network 100.

[0183] 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 505 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 first network node 111 is depicted in Figure 5. In Figure 5, 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 5.

[0184] The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 and will thus not be repeated here to simplify the description. For example, the first indication may be understood in some examples, as a, e.g., a first, availability check message, and the second indication may be understood in some examples, as another, e.g., a second, availability check message.

[0185] Action 501

[0186] In some embodiments, the method may comprise one or more of Action 501 , Action 502 and Action 503.

[0187] In this Action 501, the first network node 111 may receive, from the wireless device 130, the first indication.

[0188] The first indication may request the first availability check of the first protocol layer of the control plane.

[0189] Action 502

[0190] In this Action 502, the first network node 111 may send, to the first wireless device 130, the second indication indicating the second availability check of the first protocol layer of the control plane.

[0191] Action 503

[0192] In this Action 503, the first network node 111 may send, to the wireless device 130, the third indication indicating to perform the RRC reconfiguration, that is, the RRC reconfiguration referred to herein as the another RRC reconfiguration.

[0193] Action 504

[0194] In this Action 504, the first network node 111 may detect the unavailability of the first protocol layer of the control plane, based on one of: i) the failure of the verification, ii) the time elapsed since when the last first indication was obtained from the wireless device 130, and iii) the insufficient number of first indications were obtained from the wireless device 130 within the second period. Action 505

[0195] In this Action 505, the first network node 111 sends the fourth indication to the wireless device 130. The fourth indication indicates the detected unavailability of the first protocol layer of the control plane. The sending in this Action 505 is performed before the protocol layer of the user plane between the first network node 111 and the wireless device 130 has become unreliable.

[0196] The fourth indication may be based on the detected unavailability in Action 504.

[0197] The sending in this Action 505 of the fourth indication may be based on one of the first indication and the second indication.

[0198] In some embodiments, one of the following may apply: a) the unavailability of the first protocol layer of the control plane may be a condition for triggering mobility, b) the detected unavailability of the first protocol layer of the control plane may be understood to lead to the inability of the wireless device 130 to comply with the control plane procedure, and c) unreliable may indicate that radio link failure is to be declared by the wireless device 130.

[0199] The inability may comprise the inability to perform the RRC reconfiguration sent by the first network node 111 , that is, the RRC reconfiguration referred to herein as the another RRC reconfiguration.

[0200] Non-limiting example implementations of embodiments herein are provided in Figures 6- 10 in this document. In Figures 6-10, the wireless device 130 is a UE, the first network node 111 is a source gNB and the second network node 112 is a target gNB.

[0201] Figure 6 is a signalling diagram depicting a non-limiting example of CP provisioning problems, wherein, according embodiments herein, mobility may be triggered by the inability of the wireless device 130 to comply with the RRCReconfiguration indicated by the first network node 111 according to Action 403 and Action 503. As described in the section entitled “RRC connection re-establishment”, in 5G NR, when a UE cannot complywith a configuration provided by the NW, e.g., an RRCReconfiguration message, it may initiate RRC connection reestablishment. In the procedures of examples of embodiments herein relating to mobility triggered by the wireless device 130 following failure to comply with a network node-provisioned configuration, the wireless device 130 may, according to Action 406, trigger a mobility procedure when it may determine in Action 405 that it is unable to comply with a configuration provided by the NW, e.g., the first network node 111 , e.g., in an RRCReconfiguration message received according to Action 403 and Action 503.

[0202] Figure 7 is a signalling diagram depicting one additional non-limiting example of CP provisioning problems, wherein, according embodiments herein, the wireless device 130 may indicate to the NW, e.g., the second network node 112, according to Action 407, that the mobility procedure was initiated due to the inability to comply with the provided configuration, e.g., a RRCReconfiguration. For example, this information may be indicated implicitly as a field in a message, e.g., a message that may be sent to the second network node 112 as part of the mobility procedure, such as an RRCReconfigurationComplete message, or explicitly, e.g., by using a specific sequence or resource for transmission of a (random) access signal. The wireless device 130 may receive an RRCReconfiguration from the source first network node 111 according to Action 403 and Action 503. It may attempt to apply the configuration carried by the received message but it may be unable, as it may determine in Action 405. Consequently, the wireless device 130 may trigger a mobility procedure according to Action 406 that may take the wireless device 130 to change to a new serving network node, the second network node 112, e.g., a target gNB. As part of the mobility procedure, the wireless device 130 may send, according to Action 407, an RRCReconfigurationCompletef) message to the second network node 112. The message may indicate to the second network node 112 that the mobility procedure was initiated due to the inability to comply with the RRCReconfiguration from the source network node, that is, the first network node 111. It may be noted that the RRCReconfigurationCompletef) message may not indicate the completion of the RRCReconfiguration provided by the source first network node 111 , rather it may indicate that at least a part of the mobility procedure, which may typically involve different RRCReconfiguration message, has been completed.

[0203] Figure 8 is a signalling diagram depicting a non-limiting example of CP provisioning problems, wherein, according embodiments herein, the wireless device 130 may detect CP availability issues, according to the unidirectional protocol. The wireless device 130 may perform an integrity check based on received CP messages according to Action 402 and Action 502. If any of the conditions described in conditions for the wireless device 130, e.g., Conditions for the UE, to declare CP availability issues is fulfilled, the wireless device 130 may consider CP as unavailable in Action 405. The wireless device 130 may not receive a CP availability check message for T seconds and may trigger mobility according to Action 406. If the additional optional conditions associated to a mobility event are also fulfilled, the wireless device 130 may start a mobility procedure according to Action 406 as described earlier.

[0204] Figure 9 is a signalling diagram depicting another non-limiting example of CP provisioning problems, wherein, according embodiments herein, the wireless device 130 may detect CP availability issues, according to the bidirectional protocol. The wireless device 130 may not receive, according to Action 401 and Action 402, a second valid CP availability check message for T seconds after transmission of the first message according to Action 401 and Action 402, and may trigger mobility according to Action 406. In this example approach, the wireless device 130 may transmit a first challenge message to the first network node 111 according to Action 401 and Action 402, and based on the response received from the first network node 111 according to Action 402 and Action 502, the wireless device 130 may trigger the mobility procedure according to Action 406. In this example, the second message may be not received correctly according to Action 402, and a new valid second message may be not received by the UE within T seconds from the first message transmission, hence the mobility procedure may be triggered according to Action 406.

[0205] Figure 10 is a signalling diagram depicting yet another non-limiting example of CP provisioning problems, wherein, according embodiments herein, the first network node 111 may detect CP availability issues in Action 504, according to the bidirectional protocol. In this example approach, the wireless device 130 may, according to Action 401 and Action 501 , transmit a first challenge message to the first network node 111 , which may detect issues in the message integrity according to Action 504, and report it to the wireless device 130 according to Action 505 and Action 404, which may trigger the mobility procedure according to Action 406.

[0206] All the procedures described herein may be specified by means of defining new triggers for conditional handover.

[0207] As a summarized overview of the foregoing, embodiments herein may be understood to relate to a set of methods for assessing the health of the control plane between the wireless device 130 and the NW, e.g., the first network node 111 , by using one-way or two-way signaling. The health assessment may be made by the wireless device 130 or by the first network node 111 , e.g., a gNB. If the control plane is considered to be unhealthy or broken, the wireless device 130 may initiate or trigger a mobility procedure.

[0208] Certain embodiments disclosed herein may provide one or more of the following technical advantage(s), which may be summarized as follows.

[0209] 3GPP specifications include several procedures for recovering connectivity in case of problems, by detecting poor radio conditions or user plane problems. Those types of issues may be understood to determine nearly instantaneous service degradation and may be understood to be relatively easy to detect. Embodiments herein may be understood to deal with other types of issues, related to control signaling. Since control signaling, e.g., RRC re-configurations, may be understood to be only performed occasionally, problems in control plane may pass unnoticed until the control plane may be used, which may be often associated to urgent and critical tasks such as mobility, which may be understood to not allow for recovery before service interruption may occur. Differently from current specifications, embodiments herein may allow for early detection of failures in the control plane between the wireless device 130 and the NW, e.g., the first network node 111 , 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.

[0210] By leveraging mobility procedures, embodiments herein may allow the wireless device 130 to deal with control plane connectivity problems in a faster way than by following some or all of the steps of: declaration of radio Link failure, which may typically take ~2 seconds, performing cell search, which may take multiple seconds, RRC connection re-establishment, which may take 100s of milliseconds.

[0211] In this way, a detected control plane issue may be addressed in 50-100 ms, which may be tolerated by many applications.

[0212] Some related concepts are available in existing methods and specifications. The concept of periodically verifying the availability of a communication channel, sometimes referred to as watchdog, may be understood to be known, for example, in the context of industrial networks. However, according to embodiments herein, availability checks may be performed on the control plane of the communication channel, instead of using the user plane as commonly done with a watchdog. This may be understood to provide a technical advantage by allowing early detection of control plane procedures, before they may potentially affect the user plane.

[0213] The concept of indirectly triggering a connection re-establishment to recover radio problems may be understood to be known in 3GPP. For example, a UE may declare RLF after loss of radio synchronization. Conditional handover may be another such procedure, where certain radio conditions or user plane issues may trigger mobility. However, these types of procedures may be understood to be slow because they require time for detecting the degraded radio conditions or user plane degradation. In other words, service recovery is only started after the service has been degraded, while embodiments herein may enable to start service recovery before the degradation may affect user plane and service quality, providing a technical advantage over existing methods.

[0214] Figure 11 and Figure 12 are schematic diagrams illustrating some of the technical advantages of embodiments herein. Figure 11 is a schematic diagram illustrating legacy procedure for UE-triggered connection re-establishment following control plane issues. As depicted in Figure 11 , after a control plane failure, the user plane is affected and a UE may declare radio Link failure, which may typically take ~2 seconds. The UE may then perform cell search and selection, which may take multiple seconds, followed by the UE performing RRC connection re-establishment, which may take 100s of milliseconds, after which the user plane may be restored. During this procedure, communication service is affected.

[0215] Figure 12 is a schematic diagram illustrating a procedure according to embodiments herein for UE-triggered connection re-establishment following control plane issues. As depicted in Figure 12, after a control plane failure, the wireless device 130 may detect the CP failure according to Action 405, or it may be informed about it, according to Action 404 and Action 504. This may enable that the wireless device 130 may trigger a mobility procedure according to Action 405, thereby enabling that the user plane may be restored. It may be noted that the current specification of UE-triggered mobility procedures such as CHO does not support that the UE directly detects the CP failure as in Figure 12. The UE may only detect the failure of the CP indirectly at a later point in time. For example, when the UE moves to another cell without HO being used, because CP is no longer functional.

[0216] Embodiments herein may be understood to allow to recover a control plane issue without necessarily affecting the user plane / communication service.

[0217] Figure 13 depicts an example of the arrangement that the wireless device 130 may comprise to perform the method actions described above in relation to Figure 4, and / or any of Figures 6-10 and 12. The wireless device 130 is for handling the inability of the wireless device 130 to comply with the control plane procedure with the first network node 111. The wireless device 130 is configured to operate in the wireless communications network 100.

[0218] 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 first indication may be understood in some examples, as a, e.g., a first, availability check message, and the second indication may be understood in some examples, as another, e.g., a second, availability check message.

[0219] The wireless device 130 is configured and / or operable to, e.g. by means of a processing circuitry 1301 within the wireless device 130 configured to, determine the inability to comply with the control plane procedure.

[0220] The wireless device 130 is also configured and / or operable to, e.g. by means of the processing circuitry 1301 within the wireless device 130 configured to, initiate an RRC reconfiguration at the wireless device 130. The initiating is configured to be performed after the wireless device 130 has determined the inability to comply with the control plane procedure, and before the protocol layer of the user plane between the first network node 111 and the wireless device 130 has become unreliable.

[0221] In some embodiments, one or more of the following may apply: a) the RRC reconfiguration may be configured to be comprised in a mobility procedure, b) the inability may be configured to have been detected by one of: the wireless device 130 and the first network node 111 , and c) the inability may be configured to be due to the unavailability of the first protocol layer of the control plane with the first network node 111. The protocol layer of the user plane may be configured to be the second protocol layer.

[0222] In some embodiments, the wireless device 130 may be further configured with one or more of the three following configurations.

[0223] In some embodiments, the wireless device 130 may be configured and / or operable to, e.g. by means of the processing circuitry 1301 within the wireless device 130 configured to, send, to the first network node 111 , the first indication configured to request the first availability check of the first protocol layer of the control plane.

[0224] In some embodiments, the wireless device 130 may be configured and / or operable to, e.g. by means of the processing circuitry 1301 within the wireless device 130 configured to, obtain, from the first network node 111, the second indication configured to indicate the second availability check of the first protocol layer of the control plane. The determining of the inability may be configured to be based on one of the first indication and the second indication.

[0225] In some embodiments, the wireless device 130 may be configured and / or operable to, e.g. by means of the processing circuitry 1301 within the wireless device 130 configured to, obtain, from the first network node 111, the third indication configured to indicate to perform the another RRC reconfiguration. The inability may be configured to comprise the inability to perform the another RRC reconfiguration configured to be received from the first network node 111.

[0226] In some embodiments, the wireless device 130 may be configured and / or operable to, e.g. by means of the processing circuitry 1301 within the wireless device 130 configured to, obtain the fourth indication from the first network node 111. The fourth indication may be configured to indicate the detected unavailability of the first protocol layer of the control plane.

[0227] In some embodiments, the wireless device 130 may be configured and / or operable to, e.g. by means of the processing circuitry 1301 within the wireless device 130 configured to, send the fifth indication to the second network node 112. The fifth indication may be configured to indicate the inability configured to be determined.

[0228] In some embodiments, the determining may be configured to be based on one or more of the following: a) the failure of the verification, b) the time elapsed since when the last second indication was obtained from the first network node 111, and c) the insufficient number of second indications were obtained from the first network node 111 within the first time period.

[0229] In some embodiments, one or more of the following may apply: i) the unavailability of the first protocol layer of the control plane may be configured to be the condition for triggering mobility, ii) the unavailability configured to be detected of the first protocol layer of the control plane may be configured to lead to the inability of the wireless device 130 to comply with the control plane procedure, and iii) unreliable may be configured to indicate that radio link failure may be to be declared by the wireless device 130.

[0230] In some embodiments, the condition for triggering mobility may be configured to be the failure in the CRC check in the second indication configured to be obtained.

[0231] The embodiments herein in the wireless device 130 may be implemented through one or more processors, such as a processing circuitry 1301 in the wireless device 130 depicted in Figure 13, together with computer program code for performing the functions and actions of the embodiments herein. A processor, as used herein, may be understood to be a hardware component. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the 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.

[0232] The processing circuitry 1301 may be configured to, or operable to, perform the method actions according to Figure 4, and / or any of Figures 6-10 and 12.

[0233] The wireless device 130 may further comprise a memory 1302 comprising one or more memory units. The memory 1302 is arranged to be used to store obtained information, store data, configurations, schedulings, and applications etc. to perform the methods herein when being executed in the wireless device 130.

[0234] In some embodiments, the wireless device 130 may receive information from, e.g., the first network node 111, the second network node 112, the virtual node 113, other wireless devices or another structure in the wireless communications network 100, through a receiving port 1303. In some embodiments, the receiving port 1303 may be, for example, connected to one or more antennas in 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 1303. Since the receiving port 1303 may be in communication with the processing circuitry 1301 , the receiving port 1303 may then send the received information to the processing circuitry 1301. The receiving port 1303 may also be configured to receive other information. The processing circuitry 1301 in the wireless device 130 may be further configured to transmit or send information to e.g., the first network node 111, the second network node 112, the virtual node 113, other wireless devices or another structure in the wireless communications network 100, through a sending port 1304, which may be in communication with the processing circuitry 1301 , and the memory 1302.

[0235] Those skilled in the art will also appreciate that the processing circuitry 1301 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 1301, perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).

[0236] Also, in some embodiments, the wireless device 130 may be configured to perform the actions of Figure 4, and / or any of Figures 6-10 and 12 with respective units that may be implemented as one or more applications running on one or more processors such as the processing circuitry 1301.

[0237] Thus, the methods according to the embodiments described herein for the wireless device 130 may be respectively implemented by means of a computer program 1305 product, comprising instructions, i.e., software code portions, which, when executed on at least one processing circuitry 1301, cause the at least one processing circuitry 1301 to carry out the actions described herein, as performed by the wireless device 130. The computer program 1305 product may be stored on a computer-readable storage medium 1306. The computer- readable storage medium 1306, having stored there on the computer program 1305, may comprise instructions which, when executed on at least one processing circuitry 1301, cause the at least one processing circuitry 1301 to carry out the actions described herein, as performed by the wireless device 130. In some embodiments, the computer-readable storage medium 1306 may be a non-transitory computer-readable storage medium, such as a CD ROM disc, or a memory stick. In other embodiments, the computer program 1305 product may be stored on a carrier containing the computer program 1305 just described, wherein the carrier is one of an electronic signal, optical signal, radio signal, or the computer-readable storage medium 1306, as described above.

[0238] 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 network node 111 , the second network node 112, the virtual node 113, other wireless devices 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.

[0239] In other embodiments, the wireless device 130 may also comprise a radio circuitry 1307, which may comprise e.g., the receiving port 1303 and the sending port 1304. The radio circuitry 1307 may be configured to set up and maintain at least a wireless connection with the first network node 111 , the second network node 112, the virtual node 113, other wireless devices or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0240] Hence, embodiments herein also relate to the wireless device 130 comprising the processing circuitry 1301 and the memory 1302, said memory 1302 containing instructions executable by said processing circuitry 1301 , whereby the wireless device 130 is operative to perform the actions described herein in relation to the wireless device 130, e.g., in Figure 4, and / or any of Figures 6-10 and 12.

[0241] Figure 18 depicts an example of the arrangement that the first network node 111 may comprise to perform the method actions described above in relation to Figure 5, and / or any of Figures 6-10. The first network node 111 is for handling the inability of the wireless device 130 to comply with the control plane procedure with the first network node 111. The first network node 111 is configured to operate in the wireless communications network 100.

[0242] Several embodiments are comprised herein. It should be noted that the examples herein are not mutually exclusive. One or more embodiments may be combined, where applicable. All possible combinations are not described to simplify the description. Components from one embodiment may be tacitly assumed to be present in another embodiment and it will be obvious to a person skilled in the art how those components may be used in the other exemplary embodiments. The detailed description of some of the following corresponds to the same references provided above, in relation to the actions described for the first network node 111 and will thus not be repeated here. For example, the first indication may be understood in some examples, as a, e.g., a first, availability check message, and the second indication may be understood in some examples, as another, e.g., a second, availability check message.

[0243] The first network node 111 is configured and / or operable to, e.g., by means of a processing circuitry 1801 within the first network node 111 configured to, send the fourth indication to the wireless device 130. The fourth indication is configured to indicate the detected unavailability of the first protocol layer of the control plane. The sending is configured to be performed before the protocol layer of the user plane between the first network node 111 and the wireless device 130 has become unreliable. In some embodiments, the first network node 111 may be further configured with one or more of the two following configurations.

[0244] The first network node 111 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the first network node 111 configured to, receive, from the wireless device 130, the first indication configured to request the first availability check of the first protocol layer of the control plane.

[0245] The first network node 111 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the first network node 111 configured to, send, to the first wireless device 130, the second indication configured to indicate the second availability check of the first protocol layer of the control plane. The sending of the fourth indication may be configured to be based on one of the first indication and the second indication.

[0246] The first network node 111 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the first network node 111 configured to, send, to the wireless device 130, the third indication configured to indicate to perform an RRC reconfiguration. The inability may be configured to comprise the inability to perform the another RRC reconfiguration configured to be received from the first network node 111.

[0247] The first network node 111 may be configured and / or operable to, e.g., by means of the processing circuitry 1801 within the first network node 111 configured to, detect the unavailability of the first protocol layer of the control plane, based on one of: i) the failure of the verification, ii) the time configured to have elapsed since when the last first indication was configured to be obtained from the wireless device 130, and iii) the insufficient number of first indications were configured to be obtained from the wireless device 130 within the second period. The fourth indication may be configured to be based on the detected unavailability.

[0248] In some embodiments, one or more of the following may apply: a) the unavailability of the first protocol layer of the control plane may be configured to be the condition for triggering mobility, b) the unavailability configured to be detected of the first protocol layer of the control plane may be configured to lead to the inability of the wireless device 130 to comply with the control plane procedure, and c) unreliable may be configured to indicate that radio link failure is to be declared by the wireless device 130.

[0249] The embodiments herein in the first network node 111 may be implemented through one or more processors, such as a processing circuitry 1801 in the first network node 111 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 first network node 111. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the first network node 111.

[0250] The processing circuitry 1801 may be configured to, or operable to, perform the method actions according to Figure 5, and / or any of Figures 6-10.

[0251] The first network node 111 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 first network node 111.

[0252] In some embodiments, the first network node 111 may receive information from, e.g., the second network node 112, the virtual node 113, the wireless device 130, other wireless devices 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 first network node 111. In other embodiments, the first network node 111 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.

[0253] The processing circuitry 1801 in the first network node 111 may be further configured to transmit or send information to e.g., the second network node 112, the virtual node 113, the wireless device 130, other wireless devices 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.

[0254] 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).

[0255] Also, in some embodiments, the first network node 111 may be configured to perform the actions of Figure 5, and / or any of Figures 6-10 with respective units that may be implemented as one or more applications running on one or more processors such as the processing circuitry 1801.

[0256] Thus, the methods according to the embodiments described herein for the first network node 111 may be respectively implemented by means of a computer program 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 first network node 111. 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 first network node 111. 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.

[0257] The first network node 111 may comprise a communication interface configured to facilitate communications between the first network node 111 and other nodes or devices, e.g., the second network node 112, the virtual node 113, the wireless device 130, other wireless devices 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.

[0258] In other embodiments, the first network node 111 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 second network node 112, the virtual node 113, the wireless device 130, other wireless devices and / or another structure in the wireless communications network 100. Circuitry may be understood herein as a hardware component.

[0259] Hence, embodiments herein also relate to the first network node 111 comprising the processing circuitry 1801 and the memory 1802, said memory 1802 containing instructions executable by said processing circuitry 1801 , whereby the first network node 111 is operative to perform the actions described herein in relation to the first network node 111 , e.g., in Figure 5, and / or any of Figures 6-10.

[0260] When using the word "comprise" or “comprising”, it shall be interpreted as non- limiting, i.e., meaning "consist at least of".

[0261] 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. 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.

[0262] 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.

[0263] Any of the terms processor and circuitry may be understood herein as a hardware component.

[0264] 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.

[0265] 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.

[0266] REFERENCES

[0267] 1. 3GPP TS 38.300 version 17.5.0, , 30th June 2023.

[0268] 2. 3GPP TS 38.331 version 18.1.0.

Claims

CLAIMS:1 . A computer-implemented method performed by a wireless device (130), the method being for handling an inability of the wireless device (130) to comply with a control plane procedure with a first network node (111), the wireless device (130) operating in a wireless communications network (100), and the method comprising:- determining (405) the inability to comply with the control plane procedure, and- initiating (406) a Radio Resource Control, RRC, reconfiguration at the wireless device (130), wherein the initiating (406) is performed after the wireless device (130) has determined the inability to comply with the control plane procedure, and before a protocol layer of a user plane between the first network node (111) and the wireless device (130) has become unreliable.

2. The method according to claim 1 , wherein one or more of:- the RRC reconfiguration is comprised in a mobility procedure,- the inability has been detected by one of: the wireless device (130) and the first network node (111), and- the inability is due to an unavailability of a first protocol layer of the control plane with the first network node (111), wherein the protocol layer of the user plane is a second protocol layer.

3. The method according to claim 2, wherein the method further comprises one or more of:- sending (401), to the first network node (111), a first indication requesting a first availability check of the first protocol layer of the control plane,- obtaining (402), from the first network node (111), a second indication indicating a second availability check of the first protocol layer of the control plane, and wherein the determining (405) of the inability is based on one of the first indication and the second indication, and- obtaining (403), from the first network node (111), a third indication indicating to perform another RRC reconfiguration, and wherein the inability comprises an inability to perform the another RRC reconfiguration received from the first network node (111).

4. The method according to any of claims 2-3, wherein the method further comprises:obtaining (404) a fourth indication from the first network node (111), the fourth indication indicating a detected unavailability of the first protocol layer of the control plane.

5. The method according to any of claims 1-3, wherein the method further comprises:- sending (407) a fifth indication to the second network node (112), the fifth indication indicating the determined inability.

6. The method according to claim 5, wherein the determining (405) is based on one or more of:- a failure of a verification,- a time elapsed since when a last second indication was obtained from the first network node (111), and- an insufficient number of second indications were obtained from the first network node (111) within a first time period.

7. The method according to any of claims 2-6, wherein one or more of:- the unavailability of the first protocol layer of the control plane is a condition for triggering mobility, and- unreliable indicates that radio link failure is to be declared by the wireless device (130).

8. The method according to claims 7 and 3, wherein the condition for triggering mobility is a failure in a CRC check in the obtained second indication.

9. A computer-implemented method performed by a first network node (111), the method being for handling an inability of a wireless device (130) to comply with a control plane procedure with the first network node (111), the first network node (111) operating in a wireless communications network (100), and the method comprising:- sending (505) a fourth indication to the wireless device (130), the fourth indication indicating a detected unavailability of the first protocol layer of the control plane, wherein the sending (505) is performed before a protocol layer of a user plane between the first network node (111) and the wireless device (130) has become unreliable.

10. The method according to claim 9, wherein the method further comprises one or more of:- receiving (501), from the wireless device (130), a first indication requesting a first availability check of the first protocol layer of the control plane,- sending (502), to the first wireless device (130), a second indication indicating a second availability check of the first protocol layer of the control plane, and wherein the sending (505) of the fourth indication is based on one of the first indication and the second indication, and- sending (503), to the wireless device (130), a third indication indicating to perform a Radio Resource Control, RRC, reconfiguration, and wherein the inability comprises an inability to perform the RRC reconfiguration sent by the first network node (111).

11. The method according to claim 10, further comprising:- detecting (504) the unavailability of the first protocol layer of the control plane, based on one of: i. a failure of a verification, ii. a time elapsed since when a last first indication was obtained from the wireless device (130), and iii. an insufficient number of first indications were obtained from the wireless device (130) within a second period, and wherein the fourth indication is based on the detected unavailability.

12. The method according to any of claims 9-11, wherein one or more of:- the unavailability of the first protocol layer of the control plane is a condition for triggering mobility,- the detected unavailability of the first protocol layer of the control plane leads to the inability of the wireless device (130) to comply with the control plane procedure, and- unreliable indicates that radio link failure is to be declared by the wireless device (130).

13. A wireless device (130), for handling an inability of the wireless device (130) to comply with a control plane procedure with a first network node (111), the wireless device (130) being configured to operate in a wireless communications network (100), and the wireless device (130) being further configured to:- determine the inability to comply with the control plane procedure, and- initiate a Radio Resource Control, RRC, reconfiguration at the wireless device (130), wherein the initiating is configured to be performed after the wireless device (130) has determined the inability to comply with the control plane procedure, and before a protocol layer of a user plane between the first network node (111) and the wireless device (130) has become unreliable.

14. The wireless device (130) according to claim 13, wherein one or more of:- the RRC reconfiguration is configured to be comprised in a mobility procedure,- the inability is configured to have been detected by one of: the wireless device (130) and the first network node (111), and- the inability is configured to be due to an unavailability of a first protocol layer of the control plane with the first network node (111), wherein the protocol layer of the user plane is configured to be a second protocol layer.

15. The wireless device (130) according to claim 14, wherein the wireless device (130) is further configured to one or more of:- send, to the first network node (111), a first indication configured to request a first availability check of the first protocol layer of the control plane,- obtain, from the first network node (111), a second indication configured to indicate a second availability check of the first protocol layer of the control plane, and wherein the determining of the inability is configured to be based on one of the first indication and the second indication, and- obtain, from the first network node (111), a third indication configured to indicate to perform another RRC reconfiguration, and wherein the inability is configured to comprise an inability to perform the another RRC reconfiguration configured to be received from the first network node (111).

16. The wireless device (130) according to any of claims 14-15, wherein the wireless device (130) is further configured to:- obtain a fourth indication from the first network node (111), the fourth indication being configured to indicate a detected unavailability of the first protocol layer of the control plane.

17. The wireless device (130) according to any of claims 13-15, wherein the wireless device (130) is further configured to:- send a fifth indication to the second network node (112), the fifth indication being configured to indicate the inability configured to be determined.

18. The wireless device (130) according to claim 17, wherein the determining is configured to be based on one or more of:- a failure of a verification,- a time elapsed since when a last second indication was obtained from the first network node (111), and- an insufficient number of second indications were obtained from the first network node (111) within a first time period.

19. The wireless device (130) according to any of claims 14-18, wherein one or more of:- the unavailability of the first protocol layer of the control plane is configured to be a condition for triggering mobility, and- unreliable is configured to indicate that radio link failure is to be declared by the wireless device (130).

20. The wireless device (130) according to claims 19 and 15, wherein the condition for triggering mobility is configured to be a failure in a CRC check in the second indication configured to be obtained.

21. A first network node (111), for handling an inability of a wireless device (130) to comply with a control plane procedure with the first network node (111), the first network node (111) being configured to operate in a wireless communications network (100), and the first network node (111) being further configured to:- send a fourth indication to the wireless device (130), the fourth indication being configured to indicate a detected unavailability of the first protocol layer of the control plane, wherein the sending is configured to be performed before a protocol layer of a user plane between the first network node (111) and the wireless device (130) has become unreliable.

22. The first network node (111) according to claim 21 , wherein the first network node(111) is further configured to one or more of:- receive, from the wireless device (130), a first indication configured to request a first availability check of the first protocol layer of the control plane,- send, to the first wireless device (130), a second indication configured to indicate a second availability check of the first protocol layer of the controlplane, and wherein the sending of the fourth indication is configured to be based on one of the first indication and the second indication, and- send, to the wireless device (130), a third indication configured to indicate to perform a Radio Resource Control, RRC, reconfiguration, and wherein the inability is configured to comprise an inability to perform the another RRC reconfiguration configured to be received from the first network node (111).

23. The first network node (111) according to claim 22, being further configured to:- detect the unavailability of the first protocol layer of the control plane, based on one of: i. a failure of a verification, ii. a time configured to have elapsed since when a last first indication was configured to be obtained from the wireless device (130), and iii. an insufficient number of first indications were configured to be obtained from the wireless device (130) within a second period, and wherein the fourth indication is configured to be based on the detected unavailability.

24. The first network node (111) according to any of claims 21-23, wherein one or more of:- the unavailability of the first protocol layer of the control plane is configured to be a condition for triggering mobility,- the unavailability configured to be detected of the first protocol layer of the control plane is configured to lead to the inability of the wireless device (130) to comply with the control plane procedure, and- unreliable is configured to indicate that radio link failure is to be declared by the wireless device (130).

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