WO2022058107A1

WO2022058107A1 - Connection re-establishment avoidance due to connection reconfiguration failure

Info

Publication number: WO2022058107A1
Application number: PCT/EP2021/072728
Authority: WO
Inventors: Subramanya CHANDRASHEKAR; Ethiraj Alwar
Original assignee: Nokia Technologies Oy
Priority date: 2020-09-15
Filing date: 2021-08-16
Publication date: 2022-03-24

Abstract

The present disclosure relates generally to the field of wireless communications and, in particular, to techniques for rolling back failed connection reconfigurations on both a network side and a UE side based on UE capability and the nature of the failed connection reconfigurations. The UE capability implies herein that a UE is configured to support the rollback of failed connection reconfigurations from a predefined list of connection reconfigurations. The UE informs a RAN node about this UE capability, so that the RAN node could also decide whether to roll back the connection reconfiguration for the UE when the connection reconfiguration is determined to be failed in the UE. At the same time, whenever said rollback is impossible (e.g., the UE decides not to use the UE capability for some reason), the legacy connection re-establishment procedure may be used as a fallback mechanism. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection re-establishment (triggered by a connection reconfiguration failure) for non-mandatory scenarios (i.e. where the connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

Description

CONNECTION RE-ESTABLISHMENT AVOIDANCE DUE TO CONNECTION RECONFIGURATION FAILURE

TECHNICAL FIELD

The present disclosure relates generally to the field of wireless communications and, in particular, to techniques for rolling back failed connection reconfigurations on both a network side and a user equipment (UE) side based on UE capability and the nature of the failed connection reconfigurations.

BACKGROUND

The Radio Resource Control (RRC) protocol belongs to the 3GPP protocol stack used in a wireless communications network and handles control plane signalling between a UE and a Radio Access Network (RAN) node (e.g., gNB in terms of 5G New Radio (NR)). One of the main functions of the RRC protocol is RRC Connection re-establishment which is used for reestablishing an RRC connection between the UE and the network, for example, upon an RRC connection reconfiguration failure at the UE. In turn, RRC connection reconfiguration may be required to modify UE configuration pertaining to the RRC connection. The RAN node notifies the UE about the RRC connection reconfiguration in a dedicated message called RRCReconfiguration.

Upon encountering the RRC connection reconfiguration failure, the UE will trigger the RRC connection re-establishment due to its inability to comply with RRCReconfiguration. The RRC connection re-establishment involves the resumption of Signalling Radio Bearer 1 (SRB1) operation and, therefore, results in the interruption of all ongoing services since all Data Radio Bearers (DRBs) have to be re-established after SRB1 re-establishment.

At this time, the RRC connection re-establishment is initiated whenever the RRC connection reconfiguration failure occurs on the UE side. However, there are scenarios in which the RRC connection reconfiguration may be optional in nature, thereby causing no damage in case of its failure on the UE side. For such scenarios, it would be desirable to provide the possibility of rolling back the failed RRC connection reconfiguration both on the network side and the UE side.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure.

It is an objective of the present disclosure to provide a technical solution that enables a rollback of failed connection reconfigurations based on UE capability and the nature of the failed connection reconfigurations.

The objective above is achieved by the features of the independent claims in the appended claims. Further embodiments and examples are apparent from the dependent claims, the detailed description and the accompanying drawings.

According to a first aspect, a RAN node for wireless communications is provided. The RAN node comprises a processor, a memory coupled to the processor and configured to store processor-executable instructions, and a transceiver coupled to the processor. When executed, the processor-executable instructions cause the operation of the processor. More specifically, the processor prepares a connection reconfiguration for a radio connection established between a UE and the RAN node. The connection reconfiguration is intended to be one of a predefined list of connection reconfigurations. Then, the processor causes the transceiver to send a message about the connection reconfiguration to the UE. Further, the processor detects that the UE has failed to perform the connection reconfiguration of the radio connection, and proceeds to check whether the UE belongs to a predefined set of UEs configured to support a rollback of failed connection reconfigurations from the predefined list of connection reconfigurations. If the UE belongs to the predefined set of UEs, the processors rolls back the failed connection reconfiguration for the radio connection. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection re-establishment (triggered by a connection reconfiguration failure) for non-mandatory scenarios (i.e. where connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

In one example embodiment of the first aspect, the processor is further configured to reestablish the radio connection if the UE is absent in the predefined set of UEs. This may provide a fallback mechanism wheneverthe rollback of the failed connection reconfiguration is impossible.

In one example embodiment of the first aspect, the predefined set of UEs is obtained as follows. The processor first causes the transceiver to send a rollback capability enquiry to all UEs that have established radio connections with the RAN node, and then causes the transceiver to receive UE notifications about whether the UEs support the rollback of failed connection reconfigurations from the predefined list of connection reconfigurations. By so doing, it is possible to properly detect those UEs which are provided with a rollback capability. Moreover, the rollback capability enquiry may subsequently be sent from the RAN node to the UEs at regular or irregular intervals, thereby making it possible to update the predefined set of UEs (e.g., in case if some of the UEs decide not to use the rollback capability after a while for some reason).

In one example embodiment of the first aspect, the processor is configured to detect that the UE has failed to perform the connection reconfiguration in response to the transceiver receiving a reconfiguration failure message from the UE. By so doing, it is possible to detect the connection reconfiguration failure more efficiently.

In another example embodiment of the first aspect, the processor is configured to detect that the UE has failed to perform the connection reconfiguration if there is no reconfiguration complete message received by the transceiver from the UE within a predefined timer. By so doing, it is possible to detect the connection reconfiguration failure even when the UE is unable to inform the RAN node about the connection reconfiguration failure.

In one example embodiment of the first aspect, the predefined list of connection reconfigurations comprises at least one of the following: an addition of at least one new Data Radio Bearer (DRB) for the radio connection in a standalone (SA) deployment scenario; an addition of at least one new DRB for the radio connection in a non-SA (NSA) deployment scenario; an addition of at least one secondary cell for carrier aggregation in the SA or NSA deployment scenario; and a configuration of some optional (i.e. scenario-dependent) channel measurements for the radio connection. The predefined list of connection reconfigurations may also comprise any such similar scenario resulting in an optional reconfiguration. This may make the RAN node according to the first aspect more flexible in use.

According to a second aspect, a UE for wireless communications is provided. The UE comprises a processor, a memory coupled to the processor and configured to store processor-executable instructions, and a transceiver coupled to the processor. When executed, the processor-executable instructions cause the operation of the processor. More specifically, the processor causes the transceiver to send a UE notification to a RAN node with which the UE has established a radio connection. The UE notification indicates that the UE supports a rollback of failed connection reconfigurations from a predefined list of connection reconfigurations. Then, the processor causes the transceiver to receive, from the RAN node, a message about a connection reconfiguration to be performed for the radio connection. The connection reconfiguration is intended to be one of the predefined list of connection reconfigurations. If the connection reconfiguration fails to perform, the processor rolls back the failed connection reconfiguration. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection re-establishment (triggered by a connection reconfiguration failure) for non-mandatory scenarios (i.e. where connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

In one example embodiment of the second aspect, the processor is configured to cause the transceiver to send the UE notification in response to a rollback capability enquiry received by the transceiver from the RAN node. This may allow the UE to promptly inform the RAN node about its rollback capability.

In one example embodiment of the second aspect, the processor is further configured, if the connection reconfiguration fails to perform, to generate a reconfiguration failure message and cause the transceiver to send the reconfiguration failure message to the RAN node. By so doing, the RAN node may be properly informed of the connection reconfiguration failure on the UE side. In one example embodiment of the second aspect, the predefined list of connection reconfigurations comprises at least one of the following: an addition of at least one new DRB for the radio connection in a SA deployment scenario; and an addition of at least one new DRB for the radio connection in an NSA deployment scenario; an addition of at least one secondary cell for carrier aggregation in the SA or NSA deployment scenario; and a configuration of some optional channel measurements for the radio connection. The predefined list of connection reconfigurations may also comprise any such similar scenario resulting in an optional reconfiguration. This may allow the UE according to the second aspect to use the rollback capability in a flexible manner.

According to a third aspect, a method for operating a RAN node in a wireless communication network is provided. The method starts with the step of preparing a connection reconfiguration for a radio connection established between a UE and the RAN node. The connection reconfiguration is intended to be one of a predefined list of connection reconfigurations. Then, the method proceeds to the step of sending a message about the connection reconfiguration to the UE. Further, the method goes to the step of detecting that the UE has failed to perform the connection reconfiguration of the radio connection. After that, the next step is initiated, in which it is checked if the UE belongs to a predefined set of UEs configured to support a rollback of failed connection reconfigurations from the predefined list of connection reconfigurations. If the UE belongs to the predefined set of UEs, the method proceeds to the step of rolling back the failed connection reconfiguration for the radio connection. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection reestablishment (triggered by a connection reconfiguration failure) for non-mandatory scenarios (i.e. where connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

In one example embodiment of the third aspect, the method further comprises the step of re-establishing the radio connection if the UE is absent in the predefined set of UEs. This may provide a fallback mechanism wheneverthe rollback of the failed connection reconfiguration is impossible.

In one example embodiment of the third aspect, the predefined set of UEs is obtained as follows. At first, a rollback capability enquiry is sent from the RAN node to all UEs that have established radio connections with the RAN node. Then, the RAN node receives UE notifications about whether the UEs support the rollback of failed connection reconfigurations from the predefined list of connection reconfigurations. By so doing, it is possible to properly detect those UEs which are provided with the rollback capability. Moreover, the rollback capability enquiry may subsequently be sent from the RAN node to the UEs at regular or irregular intervals, thereby making it possible to update the predefined set of UEs (e.g., in case if some of the UEs decide not to use the rollback capability after a while for some reason).

In one example embodiment of the third aspect, the step of detecting comprises detecting that the UE has failed to perform the connection reconfiguration in response to a reconfiguration failure message received from the UE. By so doing, it is possible to detect the connection reconfiguration failure more efficiently.

In another example embodiment of the third aspect, the step of detecting comprises detecting that the UE has failed to perform the connection reconfiguration if there is no reconfiguration complete message received from the UE within a predefined timer. By so doing, it is possible to detect the connection reconfiguration failure even when the UE is unable to inform the RAN node about the connection reconfiguration failure.

In one example embodiment of the third aspect, the predefined list of connection reconfigurations comprises at least one of the following: an addition of at least one new DRB for the radio connection in a SA deployment scenario; an addition of at least one new DRB for the radio connection in an NSA deployment scenario; an addition of at least one secondary cell for carrier aggregation in the SA or NSA deployment scenario; and a configuration of some optional channel measurements for the radio connection. The predefined list of connection reconfigurations may also comprise any such similar scenario resulting in an optional reconfiguration. This may make the method according to the third aspect more flexible in use.

According to a fourth aspect, a method for operating a UE in a wireless communications network is provided. The method starts with the step of sending a UE notification to a RAN node with which the UE has established a radio connection. The UE notification indicates that the UE supports a rollback of failed connection reconfigurations from a predefined list of connection reconfigurations. Then, the method proceeds to the step of receiving, from the RAN node, a message about a connection reconfiguration to be performed for the radio connection. The connection reconfiguration is intended to be one of the predefined list of connection reconfigurations. Further, if the connection reconfiguration fails to perform, the method goes to the step of rolling back the failed connection reconfiguration for the radio connection. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection re-establishment (triggered by a connection reconfiguration failure) for non-mandatory scenarios (i.e. where connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

In one example embodiment of the fourth aspect, the step of sending the UE notification is performed in response to a rollback capability enquiry received from the RAN node. This may allow the UE to promptly inform the RAN node about its rollback capability.

In one example embodiment of the fourth aspect, the method further comprises the steps of generating a reconfiguration failure message if the connection reconfiguration fails to perform, and sending the reconfiguration failure message to the RAN node. By so doing, the RAN node may be properly informed of the connection reconfiguration failure on the UE side.

In one example embodiment of the fourth aspect, the predefined list of connection reconfigurations comprises at least one of the following: an addition of at least one new DRB for the radio connection in a SA deployment scenario; an addition of at least one new DRB for the radio connection in an NSA deployment scenario; an addition of at least one secondary cell for carrier aggregation in the SA or NSA deployment scenario; and a configuration of some optional channel measurements for the radio connection. The predefined list of connection reconfigurations may also comprise any such similar scenario resulting in an optional reconfiguration. This may make the method according to the fourth aspect more flexible in use.

According to a fifth aspect, a computer program product is provided. The computer program product stores a computer-readable storage medium comprising a computer code. When executed by at least one processor, the computer code causes the at least one processor to perform the method according to the third aspect. By using such a computer program product, it is possible to simplify the implementation of the method according to the third aspect in any network node, such, for example, as the RAN node according to the first aspect.

According to a sixth aspect, a computer program product is provided. The computer program product stores a computer-readable storage medium comprising a computer code. When executed by at least one processor, the computer code causes the at least one processor to perform the method according to the fourth aspect. By using such a computer program product, it is possible to simplify the implementation of the method according to the fourth aspect in any computing device, such, for example, as the UE according to the second aspect.

According to a seventh aspect, a RAN node for wireless communications is provided. The RAN node comprises a processing means for preparing a connection reconfiguration for a radio connection established between a UE and the RAN node. The connection reconfiguration is intended to be one of a predefined list of connection reconfigurations. The RAN node further comprises a means for sending a message about the connection reconfiguration to the UE. The RAN node further comprises a means for detecting that the UE has failed to perform the connection reconfiguration of the radio connection, and a means for checking whether the UE belongs to a predefined set of UEs configured to support a rollback of failed connection reconfigurations from the predefined list of connection reconfigurations. The RAN node further comprises a means for rolling back, if the UE belongs to the predefined set of UEs, the failed connection reconfiguration for the radio connection. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection re-establishment (triggered by a connection reconfiguration failure) for non-mandatory scenarios (i.e. where connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

According to an eighth aspect, a UE for wireless communications is provided. The UE comprises a means for sending a UE notification to a RAN node with which the UE has established a radio connection. The UE notification indicates that the UE supports a rollback of failed connection reconfigurations from a predefined list of connection reconfigurations. The UE further comprises a means for receiving, from the RAN node, a message about a connection reconfiguration to be performed for the radio connection. The connection reconfiguration is intended to be one of the predefined list of connection reconfigurations. The UE further comprises a means for rolling back, in case of connection reconfiguration failure, the failed connection reconfiguration for the radio connection. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection re-establishment (triggered by a connection reconfiguration failure) for non-mandatory scenarios (i.e. where connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

Other features and advantages of the present disclosure will be apparent upon reading the following detailed description and reviewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is explained below with reference to the accompanying drawings in which:

FIG. 1 shows an interaction diagram that explains the interactive behavior of a RAN node and a UE in case of successful RRC connection reconfiguration in accordance with the prior art;

FIG. 2 shows an interaction diagram that explains the interactive behavior of the RAN node and the UE in case of failed RRC connection reconfiguration in accordance with the prior art;

FIG. 3 shows a general block-scheme of a RAN node in accordance with one example embodiment;

FIG. 4 shows a flowchart of a method for operating the RAN node shown in FIG. 3 in accordance with one example embodiment;

FIG. 5 shows a general block-scheme of a UE for wireless communications in accordance with one example embodiment;

FIG. 6 shows a flowchart of a method for operating the UE shown in FIG. 5 in accordance with one example embodiment;

FIG. 7 shows an interaction diagram that explains the interactive behavior of the RAN node shown in FIG. 3 and the UE shown in FIG. 5 in accordance with one example embodiment; FIG. 8 shows an interaction diagram that explains the rollback of failed RRC connection reconfigurations in a Standalone (SA) deployment scenario in accordance with one example embodiment; and

FIG. 9 shows an interaction diagram that explains the rollback of failed RRC connection reconfigurations in a Non-SA (NSA) deployment scenario in accordance with one example embodiment.

DETAILED DESCRIPTION

Various embodiments of the present disclosure are further described in more detail with reference to the accompanying drawings. However, the present disclosure can be embodied in many other forms and should not be construed as limited to any certain structure or function discussed in the following description. In contrast, these embodiments are provided to make the description of the present disclosure detailed and complete.

According to the detailed description, it will be apparent to the ones skilled in the art that the scope of the present disclosure encompasses any embodiment thereof, which is disclosed herein, irrespective of whether this embodiment is implemented independently or in concert with any other embodiment of the present disclosure. For example, the apparatuses and methods disclosed herein can be implemented in practice by using any numbers of the embodiments provided herein. Furthermore, it should be understood that any embodiment of the present disclosure can be implemented using one or more of the features presented in the appended claims.

Unless otherwise stated, any embodiment recited herein as "example embodiment" should not be construed as preferable or having an advantage over other embodiments.

According to the example embodiments disclosed herein, a user equipment or UE for short may refer to a mobile device, a mobile station, a terminal, a subscriber unit, a mobile phone, a cellular phone, a smart phone, a cordless phone, a personal digital assistant (PDA), a wireless communication device, a desktop computer, a laptop computer, a tablet computer, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or medical equipment, a biometric sensor, a wearable device (for example, a smart watch, smart glasses, a smart wrist band, etc.), an entertainment device (for example, an audio player, a video player, etc.), a vehicular component or sensor, a smart meter/sensor, an unmanned vehicle (e.g., an industrial robot, a quadcopter, etc.), industrial manufacturing equipment, a global positioning system (GPS) device, an Internet-of-Things (loT) device, an Industrial loT (I loT) device, a machine-type communication (MTC) device, a group of Massive loT (MIoT) or Massive MTC (mMTC) devices/sensors, or any other suitable device configured to support wireless communications. In some example embodiments, the UE may refer to at least two collocated and inter-connected UEs thus defined.

As used in the example embodiments disclosed herein, a Radio Access Network node or RAN node for short may relate to a fixed point of communication forthe UE in a particular wireless communication network. The RAN node may be referred to as a base transceiver station (BTS) in terms of the 2G communication technology, a NodeB in terms of the 3G communication technology, an evolved NodeB (eNodeB) in terms of the 4G communication technology, and a gNB in terms of the 5G New Radio (NR) communication technology. The RAN node may serve different cells, such as a macrocell, a microcell, a picocell, a femtocell, and/or other types of cells. The macrocell may cover a relatively large geographic area (for example, at least several kilometers in radius). The microcell may cover a geographic area less than two kilometers in radius, for example. The picocell may cover a relatively small geographic area, such, for example, as offices, shopping malls, train stations, stock exchanges, etc. The femtocell may cover an even smaller geographic area (for example, a home). Correspondingly, the RAN node serving the macrocell may be referred to as a macro node, the RAN node serving the microcell may be referred to as a micro node, and so on.

According to the example embodiments disclosed herein, a wireless communication network, in which the UE and the RAN node communicate with each other, may refer to a cellular or mobile telecommunications network, a Wireless Local Area Network (WLAN), a Wireless Personal Area Networks (WPAN), a Wireless Wide Area Network (WWAN), a satellite communication (SATCOM) system, or any other type of wireless communication networks. Each of these types of wireless communication networks supports wireless communications according to one or more communication protocol standards. For example, the cellular network may operate according to the Global System for Mobile Communications (GSM) standard, the Code-Division Multiple Access (CDMA) standard, the Wide-Band Code-Division Multiple Access (WCDM) standard, the Time-Division Multiple Access (TDMA) standard, or any other communication protocol standard, the WLAN may operate according to one or more versions of the IEEE 802.11 standards, the WPAN may operate according to the Infrared Data Association (IrDA), Wireless USB, Bluetooth, or ZigBee standard, and the WWAN may operate according to the Worldwide Interoperability for Microwave Access (WiMAX) standard.

As used in the example embodiments disclosed herein, a radio connection between the UE and the RAN node may refer to a wireless connection which, when established, allows the UE and the RAN node to cooperate with each other. In the 5G NR communication technology, such a radio connection may be defined in accordance with the Radio Resource Control (RRC) protocol as RRC_CONNECTED state. This state is well-known in the art, for which reason its description is omitted herein. At the same time, it should be noted that the present disclosure is not limited to the above-defined RRC state, and the radio connection may be implemented as any other similar connection state which is already existing or might be invented in future.

When the radio connection is established between the UE and the RAN node, it may be required to initiate a connection reconfiguration procedure over time in order to modify the UE configuration pertaining to the radio connection. The RAN node may use such connection reconfiguration for multiple reasons, such, for example, as follows: to establish/modify/release DRBs, to perform the connection reconfiguration with synchronization, to setup/modify/release certain measurements (e.g., intra-frequency and/or interfrequency and/or inter-RAT measurements for the purpose of executing mobility events), to add/modify/release Secondary Cells (SCells) and cell groups, to deliver a handover command, to modify Quality of Service (QoS) properties of one or more DRBs.

FIG. 1 shows an interaction diagram 100 that explains the interactive behavior of the RAN node and the UE in case of successful RRC connection reconfiguration in accordance with the prior art. The interaction diagram 100 starts with a step S102, in which the RAN node determines the need to modify an RRC connection established between the RAN node and the UE, and sends a dedicated message about an RRC connection reconfiguration, i.e. RRCReconfiguration, to the UE. The UE receives this message and performs the RRC connection reconfiguration. If the RRC connection reconfiguration is performed successfully, the interaction diagram goes to a step S104, in which the UE sends a dedicated message about the completion of the RRC connection reconfiguration, i.e. RRCReconfigurationComplete, to the RAN node.

FIG. 2 shows an interaction diagram 200 that explains the interactive behavior of the RAN node and the UE in case of failed RRC connection reconfiguration in accordance with the prior art. Similar to the interaction diagram 100, the interaction diagram 200 starts with a step S202, in which the RAN node determines the need to modify the RRC connection established between the RAN node and the UE, and sends RRCReconfiguration to the UE. The UE receives this message and performs the RRC connection reconfiguration. However, in this case, the UE fails to perform the RRC connection reconfiguration. For this reason, the interaction diagram goes to a step S204, in which the UE triggers an RRC connection reestablishment procedure due to its inability to comply with RRCReconfiguration. The RRC connection re-establishment procedure involves the resumption of SRB1 operation and, therefore, results in the interruption of all ongoing services since all DRBs have to be reestablished after SRB1 re-establishment. It should be also noted that there is no explicit message about the RRC connection re-configuration failure, which would be sent from the UE to the network. Such failure is implicitly determined on the RAN node side based on a timer (i.e. if there is no reply from the UE within a preset time period).

In general, all possible RRC connection reconfigurations initiated by the RAN node may be conveniently classified into two groups based on multiple factors (or reasons) causing these RRC connection reconfigurations. The first group combines those RRC connection reconfigurations which result in unspecified UE behavior, for which reason the RRC connection re-establishment is pursued. Examples of the first group of RRC connection reconfigurations include but are not limited to a handover, reconfiguration with synchronization, modification of QoS of DRBs, etc. The second group combines those RRC connection reconfigurations which are optional in nature and cause no damage or adverse effects if the RRC connection reconfigurations are treated as failures on the UE side. Examples of the second group of RRC connection reconfigurations include but are not limited to an addition of a DRB (in case of either SA or NSA deployment scenario), an addition of Scells for carrier aggregation in the SA or NSA scenarios, a configuration of different additional measurements, such, for example, as a configuration of inter-frequency measurements when intra-frequency measurements are already in place, etc.

However, the prior art solution (see the interaction diagram 200 in FIG. 2) involves the RRC connection re-establishment whenever the RRC connection reconfiguration is failed, i.e. irrespective of the factor(s) causing the RRC connection reconfiguration. Thus, if the RRC connection reconfiguration is failed, the prior art solution will always lead to the interruption of ongoing services in the UE, even in those cases when this failure and, consequently, the RRC connection re-establishment may be ignored.

The example embodiments disclosed herein provide a technical solution that allows mitigating or even eliminating the above-sounded drawbacks peculiar to the prior art. In particular, the technical solution disclosed herein enables a rollback of failed connection reconfigurations based on UE capability and the nature of the failed connection reconfigurations. The UE capability implies herein that a UE is configured to support the rollback of failed connection reconfigurations from a predefined list of connection reconfigurations (e.g., the above-described second group of RRC connection reconfigurations). The UE informs a RAN node about this UE capability (i.e. its rollback capability), so that the RAN node could also decide whether to roll back the connection reconfiguration for the UE when the connection reconfiguration is determined to be failed in the UE. At the same time, whenever said rollback is impossible (e.g., the UE decides not to use the UE capability for some reason), the legacy connection re-establishment procedure may be used as a fallback mechanism. By so doing, it is possible to avoid all unnecessary signalling between the RAN node and the UE, as well as to avoid service interruption due to connection re-establishment (triggered by a connection reconfiguration failure) for nonmandatory scenarios (i.e. where the connection reconfigurations may be optional in nature and, therefore, their failure does not cause any adverse effects).

FIG. 3 shows a general block-scheme of a RAN node 300 in accordance with one example embodiment. The RAN node 300 is intended to be deployed in any of the above-described wireless communication networks. As shown in FIG. 3, the RAN node 300 comprises a processor 302, a memory 304, and a transceiver 306. The memory 304 stores processorexecutable instructions 308 which, when executed by the processor 302, cause the processor 302 to operate, as will be described below in more detail. It should be noted that the number, arrangement and interconnection of the constructive elements constituting the RAN node 300, which are shown in FIG. 3, are not intended to be any limitation of the present disclosure, but merely used to provide a general idea of how the constructive elements may be implemented within the RAN node 300. For example, the processor 302 may be replaced with several processors, as well as the memory 304 may be replaced with several removable and/or fixed storage devices, depending on particular applications. Furthermore, the transceiver 306 may be implemented as two individual devices, with one for a receiving operation and another for a transmitting operation. Irrespective of its implementation, the transceiver 306 is intended to be capable of performing different operations required to perform the data reception and transmission, such, for example, as signal modulation/demodulation, encoding/decoding, etc.

The processor 302 may be implemented as a CPU, general-purpose processor, singlepurpose processor, microcontroller, microprocessor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), digital signal processor (DSP), complex programmable logic device, etc. It should be also noted that the processor 302 may be implemented as any combination of one or more of the aforesaid. As an example, the processor 302 may be a combination of two or more microprocessors.

The memory 304 may be implemented as a classical nonvolatile or volatile memory used in the modern electronic computing machines. As an example, the nonvolatile memory may include Read-Only Memory (ROM), ferroelectric Random-Access Memory (RAM), Programmable ROM (PROM), Electrically Erasable PROM (EEPROM), solid state drive (SSD), flash memory, magnetic disk storage (such as hard drives and magnetic tapes), optical disc storage (such as CD, DVD and Blu-ray discs), etc. As for the volatile memory, examples thereof include Dynamic RAM, Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Static RAM, etc.

The processor-executable instructions 308 stored in the memory 304 may be configured as a computer-executable code which causes the processor 302 to perform the aspects of the present disclosure. The computer-executable code for carrying out operations or steps for the aspects of the present disclosure may be written in any combination of one or more programming languages, such as Java, C++, or the like. In some examples, the computerexecutable code may be in the form of a high-level language or in a pre-compiled form and be generated by an interpreter (also pre-stored in the memory 304) on the fly.

FIG. 4 shows a flowchart of a method 400 for operating the RAN node 300 in accordance with one example embodiment. The method 400 starts with a step S402, in which the processor 302 prepare a connection reconfiguration for a radio connection established between a UE and the RAN node 300. The connection reconfiguration is intended to be one of a predefined list of connection reconfigurations. Examples of such connection reconfigurations include but are not limited to an addition of at least one new DRB for the radio connection in the SA deployment scenario; an addition of at least one new DRB for the radio connection in the NSA deployment scenario; an addition of at least one SCell for carrier aggregation in the SA or NSA deployment scenario; and a configuration of scenariodependent channel measurements for the radio connection. The predefined list of connection reconfigurations may also comprise any such similar scenario resulting in an optional connection reconfiguration. In other words, the predefined list of connection reconfigurations may include any connection reconfigurations whose failure in the UE may be ignored (i.e. does not require connection re-establishment). When the connection reconfiguration is prepared, the method 400 proceeds to a step S404, in which the processor 302 causes the transceiver 306 to send a message about the connection reconfiguration to the UE. For example, this message may be configured as RRCReconfiguration in terms of the RRC protocol. After that, a step S406 is initiated, in which the processor 302 detects that the UE has failed to perform the connection reconfiguration of the radio connection. The method 400 further goes to a step S408, in which the processor 302 checks whether the UE belongs to a predefined set of UEs configured to support a rollback of failed connection reconfigurations from the predefined list of connection reconfigurations. Information about such UEs as well as the predefined list of connection reconfigurations may be pre-stored in the memory 304 of the RAN node 300. If the UE belongs to the predefined set of UEs, the method 400 proceeds to a step S410, in which the processor 302 rolls back the failed connection reconfiguration for the radio connection. In context of the present disclosure, the rollback of the failed connection reconfiguration means that the UE and the RAN node 300 ignore the failed connection reconfiguration and continue to use the radio connection and the UE DRBs as they were established before the failed connection reconfiguration, after performing a clean-up of resources reserved for the failed connection reconfiguration.

In one example embodiment, the method 400 comprises a further step, in which the processor 302 re-establishes the radio connection if the UE is absent in the predefined set of UEs. This may provide a fallback mechanism whenever the rollback of the failed connection reconfiguration is impossible.

In one example embodiment, the predefined set of UEs is obtained as follows. The processor 302 first causes the transceiver 306 to send a rollback capability enquiry to all UEs that have established radio connections with the RAN node 300, and then causes the transceiver 306 to receive UE notifications about whether the UEs support the rollback of failed connection reconfigurations from the predefined list of connection reconfigurations. By so doing, it is possible to properly detect those UEs which are provided with the rollback capability. Moreover, the rollback capability enquiry may subsequently be sent from the RAN node to the UEs at regular or irregular intervals, thereby making it possible to update the predefined set of UEs (e.g., in case if some of the UEs decide not to use the rollback capability after a while for some reason).

In one example embodiment, the processor 302 is configured to detect, in the step S406 of the method 400, that the UE has failed to perform the connection reconfiguration if the transceiver 306 receives an explicit reconfiguration failure message from the UE. By so doing, it is possible to detect the connection reconfiguration failure more efficiently.

In another example embodiment, the processor 302 is configured to detect, in the step S406 of the method 400, that the UE has failed to perform the connection reconfiguration if there is no reconfiguration complete message (like RRCReconfigurationComplete in terms of the RRC protocol) received by the transceiver 306 from the UE within a predefined timer. By so doing, it is possible to detect the connection reconfiguration failure even when the UE is unable to inform the RAN node 300 about the connection reconfiguration failure. FIG. 5 shows a general block-scheme of a UE 500 for wireless communications in accordance with one example embodiment. In particular, the UE 500 is intended to communicate with the RAN node 300 in any of the above-described wireless communication networks. As shown in FIG. 5, the UE 500 comprises a processor 502, a memory 504, and a transceiver 506. The memory 504 stores processor-executable instructions 508 which, when executed by the processor 502, cause the processor 502 to operate, as will be described below in more detail. It should be noted that the number, arrangement and interconnection of the constructive elements constituting the UE 500, which are shown in FIG. 5, are not intended to be any limitation of the present disclosure, but merely used to provide a general idea of how the constructive elements may be implemented within the UE 500. For example, the processor 502 may be replaced with several processors, as well as the memory 504 may be replaced with several removable and/or fixed storage devices, depending on particular applications. Furthermore, the transceiver 506 may be implemented as two individual devices, with one for a receiving operation and another for a transmitting operation. Irrespective of its implementation, the transceiver 506 is intended to be capable of performing different operations required to perform the data reception and transmission, such, for example, as signal modulation/demodulation, encoding/decoding, etc. In general, the processor 502, the memory 504 and the executable instructions 510 may be implemented in the same or similar manner as the processor 302, the memory 304 and the executable instructions 308, respectively, in the RAN node 300.

FIG. 6 shows a flowchart of a method 600 for operating the UE 500 in accordance with one example embodiment. The method 600 starts with a step S602, in which the processor 502 causes the transceiver 506 to send a UE notification to the RAN node 300 with which the UE 500 has established a radio connection. The UE notification indicates that the UE 500 supports the rollback of failed connection reconfigurations from the above-described predefined list of connection reconfigurations. It should be noted that the step S602 may be initiated in response to the rollback capability enquiry sent from the RAN node 300. Then, the method 600 proceeds to a step S604, in which the processor 502 causes the transceiver 506 to receive, from the RAN node 300, i.e. the transceiver 306, a message about a connection reconfiguration to be performed for the radio connection. The connection reconfiguration is intended to be one of the predefined list of connection reconfigurations. If the processor 502 fails to perform the connection reconfiguration prepared by the RAN node 300, i.e. the processor 302, the method 600 goes to a step S606, in which the processor 502 rolls back the failed connection reconfiguration for the radio connection.

In one example embodiment, the method 600 comprises a further step, in which the processor 502 generates a reconfiguration failure message if the connection reconfiguration fails to perform. Then, the processor 502 causes the transceiver 506 to send the reconfiguration failure message to the RAN node 300.

FIG. 7 shows an interaction diagram 700 that explains the interactive behavior of the RAN node 300 and the UE 500 in accordance with one example embodiment. In the interaction diagram 700, it is assumed that the radio connection between the UE 500 and the RAN node 300 is established in accordance with the RRC protocol, as well as the RAN node 300 is preinformed of the capability of the UE 500 to support the rollback of failed RRC connection reconfiguration from the predefined list of connection reconfigurations. The interaction diagram 700 starts with a step S702, in which the RAN node 300 determines that a new DRB has to be configured for the RRC connection of the UE 500. Given this, the RAN node 300 proceeds to prepare a corresponding RRC connection reconfiguration. After that, a message about the prepared RRC connection reconfiguration is sent from the RAN node 300 to the UE 500 in a step S704. Then, the interaction diagram 700 goes to a step S706, in which the RRC connection reconfiguration is assumed to be failed in the UE 500. The UE 500 sends an explicit message about this failure to the RAN node 300 in a step S708. Further, the UE 500 rolls back the failed RRC connection reconfiguration in a step S710, and the RAN node 300 does the same in a step S712. The interaction diagram 700 ends up with a step S714, in which data traffic continues for different ongoing communication services involving the UE 500 and the RAN node 300.

FIG. 8 shows an interaction diagram 800 that explains the rollback of failed RRC connection reconfigurations in the SA deployment scenario in accordance with one example embodiment. In the interaction diagram 800, it is assumed that the UE 500 and the RAN node 300 communicate with each other by using the 5G communication technology, for which reason the RAN node 300 is represented by a gNB. It is also assumed that the gNB 300 is pre-informed of the rollback capability of the UE 500. It should be also noted that, in the SA deployment scenario, the UE 500 uses only one Radio Access Technology (RAT) (in this case, 5G NR) to connect to a 5G Core Network (5GC), and the gNB 300 is used for both a Control Plane (CP) and a User Plane (UP) to take care of both signaling and information transfer between the UE 500 and the gNB. The gNB 300 consists of a gNB-Control Unit (CU) and a gNB-Distributed Unit (DU), and an interface between the gNB-CU and the gNB-DU is called Fl. The gNB-CU is further separated into its CP and UP parts, which are called a gNB- CU-CP and a gNB-CU-UP, respectively. The interface between the gNB-CU-CP and the gNB- CU-UP is called El which is purely a CP interface. The 5GC comprises, among others, a Network Function (NF) which is in charge of authentication and mobility, namely Access and Mobility Management Function (AMF). The NG Application Protocol (NGAP) provides the CP signalling between the gNB 300 and the AMF.

The interaction diagram 800 starts with a step S802, in which the UE 500 performs a transition into the RRC_CONNECTED state, and one or more Protocol Data Unit (PDU) sessions are established between the UE 500 and the AMF via the gNB 300 in order to initiate data transfer (for example, corresponding to different communication services). Further, in a step S804, the AMF sends a request for PDU session resource modification to the gNB-CU- CP by using the NGAP. The PDU session resource modification is assumed to consist in adding a new QoS flow in the PDU session. In response to receiving this request, the gNB-CU-CP initiates a step S806 which consists in adding the new QoS flow to the PDU session or, in other words, adding a new DRB to the RRC connection of the UE 500.

As shown in FIG. 8, the step S806 comprises substeps S806-1 - S806-6. The gNB-CU-CP and the gNB-CU-UP perform a bearer context modification procedure by using the El Application Protocol (E1AP) in the substep S806-1. Then, in the substep S806-2, the gNB-CU-CP, the gNB- CU-UP and the gNB-DU perform a UE context modification procedure by using the Fl Application Protocol (F1AP). The bearer context modification procedure and the UE context modification procedure are well-known in the art, for which reason their description is omitted herein. In the next substep S806-3, the UE 500 receives a message about an RRC connection reconfiguration which is required to add the new DRB to the RRC connection. Further, the UE 500 is assumed to fail to perform the RRC connection reconfiguration in the substep 806-4, and sends a message about an RRC connection reconfiguration failure to the gNB 300 (i.e. the gNB-CU-CP) in the substep S806-5. The gNB-CU-CP receives this message in the substep S806-6, whereupon the interaction diagram 800 proceeds to a step S808. As shown in FIG. 8, the step S808 comprises substeps S808-1 and S808-2. Given the rollback capability of the UE 500, the bearer context modification procedure and the UE context modification procedure are again performed in the gNB 300 to delete the new QoS flow requested by the AMF, thereby rolling back the failed RRC connection reconfiguration and reverting back to the previously established configuration (i.e. that established in the step S802).

After that, the interaction diagram 800 goes to a step S810, in which the gNB-CU-CP sends a PDU session resource modify response to the AMF. In particular, this response indicates that the new QoS flow has not been added to the PDU session, and the previously established configuration is still in force. The interaction diagram 800 ends up with a step S812, in which the UE 500 is still in the RRC_CONNECTED state, and the data transfer continues for the PDU sessions without any interruption.

FIG. 9 shows an interaction diagram 900 that explains the rollback of failed RRC connection reconfigurations in the NSA deployment scenario in accordance with one example embodiment. As follows from the interaction diagram 900, the NSA deployment scenario involves a NR dual connectivity (DC) scenario, in which the UE 500 uses one gNB that acts as a master node and one gNB that acts as a secondary node in order to establish NR-DC. The master node provides the connectivity to a 5GC. Each of the master gNB and the secondary gNB may be implemented as the RAN node 300. Similar to the interaction diagram 800, each of the master gNB and the secondary gNB in the interaction diagram 900 is assumed to consist of a gNB-CU and a gNB-DU. In FIG. 9, "m" and "s" are used to differentiate between the gNB-CUs and gNB-DUs of the master and secondary gNBs, respectively. An interface between the master gNB and the secondary gNB is called Xn. It is also assumed that the master gNB is pre-informed of the rollback capability of the UE 500. This rollback capability of the UE 500 is also expected to be shared with the secondary gNB in order to be used for autonomous RRC reconfigurations that the secondary gNB may provide to the UE 500 subsequent to the NR-DC establishment.

The interaction diagram 900 starts with a step S902, in which the UE 500 performs a transition into the RRC_CONNECTED state, and one or more PDU sessions are established between the UE 500 and the 5GC via the master gNB in order to initiate data transfer (for example, corresponding to different communication services). Given the mastergNB and the secondary gNB, some of QoS flows and their corresponding DRBs from the 5GC may be split therebetween. Such DRBs are called split-DRBs or NR-DC DRBs. Further, in a step S904, the 5GC initiates adding a new QoS Flow to be configured in split mode. A corresponding request for PDU session resource modification is sent from the 5GC to the master gNB-CU in a step S906 by using the NGAP. In turn, the master gNB-CU forwards this request to in a step S908 to configure a split QoS flow in the secondary gNB. The secondary gNB configures the split QoS flow in a step S910, and sends a corresponding QoS flow addition acknowledgement to the master gNB in a step S912. In response to receiving this acknowledgement, the master gNB also configures a split QoS flow in a step S914. After that, the master gNB informs, in a step S916, the UE 500 about an RRC connection reconfiguration to performed in the UE 500. It is assumed that the UE 500 fails to perform the RRC connection reconfiguration, for which reason the UE 500 sends a message about an RRC connection reconfiguration failure to the master gNB. The master gNB-CU receives this message in a step S918. Then, the interaction diagram 900 proceeds to a step 920, in which the master gNB-CU informs the secondary gNB-CU about the necessity of rolling back the failed RRC connection reconfiguration. The master gNB rolls back the failed RRC connection reconfiguration (i.e. deletes the configured split QoS flow) in a step S922, and the secondary gNB does the same in a step S924.

After that, the interaction diagram 900 goes to a step S926, in which the master gNB-CU sends a PDU session resource modify response to the 5GC. In particular, this response indicates that the requested split QoS flow has not been added to the PDU session, and the previously used RRC connection along with the PDU sessions configured earlier is still in force. The interaction diagram 900 ends up with a step S928, in which the UE 500 continues to be in the RRC_CONNECTED state, and the data transfer continues for the PDU sessions without any interruption.

It should be noted that each step or operation of the methods 400, 600 and the interaction diagram 700-900, or any combinations of the steps or operations, can be implemented by various means, such as hardware, firmware, and/or software. As an example, one or more of the steps or operations described above can be embodied by processor executable instructions, data structures, program modules, and other suitable data representations. Furthermore, the processor-executable instructions which embody the steps or operations described above can be stored on a corresponding data carrier and executed by the processors 302 and 502. This data carrier can be implemented as any computer-readable storage medium configured to be readable by said at least one processor to execute the processor executable instructions. Such computer-readable storage media can include both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, the computer-readable media comprise media implemented in any method or technology suitable for storing information. In more detail, the practical examples of the computer-readable media include, but are not limited to information-delivery media, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile discs (DVD), holographic media or other optical disc storage, magnetic tape, magnetic cassettes, magnetic disk storage, and other magnetic storage devices.

Although the example embodiments of the present disclosure are described herein, it should be noted that any various changes and modifications could be made in the embodiments of the present disclosure, without departing from the scope of legal protection which is defined by the appended claims. In the appended claims, the word "comprising" does not exclude other elements or operations, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

24

CLAIMS A Radio Access Network (RAN) node for wireless communications, comprising: a processor; a memory coupled to the processor and configured to store processor-executable instructions; and a transceiver coupled to the processor; wherein the processor is configured, when executing the processor-executable instructions, to: prepare a connection reconfiguration for a radio connection established between a user equipment (UE) and the RAN node, the connection reconfiguration relating to a predefined list of connection reconfigurations; cause the transceiver to send a message about the connection reconfiguration to the UE; detect that the UE has failed to perform the connection reconfiguration of the radio connection; check whether the UE belongs to a predefined set of UEs configured to support a rollback of failed connection reconfigurations that relate to the predefined list of connection reconfigurations; and if the UE belongs to the predefined set of UEs, roll back the failed connection reconfiguration for the radio connection. The RAN node of claim 1, wherein, if the UE is absent in the predefined set of UEs, the processor is further configured to re-establish the radio connection. The RAN node of claim 1 or 2, wherein the processor is further configured to obtain the predefined set of UEs by:

- causing the transceiver to send a rollback capability enquiry to all UEs that have established radio connections with the RAN node; and

- causing the transceiver to receive UE notifications about whether the UEs support the rollback of failed connection reconfigurations that relate to the predefined list of connection reconfigurations. The RAN node of any one of claims 1 to 3, wherein the processor is configured to detect that the UE has failed to perform the connection reconfiguration in response to the transceiver receiving a reconfiguration failure message from the UE. The RAN node of any one of claims 1 to 3, wherein the processor is configured to detect that the UE has failed to perform the connection reconfiguration if there is no reconfiguration complete message received by the transceiver from the UE within a predefined timer. The RAN node of any one of claims 1 to 5, wherein the predefined list of connection reconfigurations comprises at least one of the following:

- an addition of at least one new Data Radio Bearer (DRB) for the radio connection in a standalone (SA) deployment scenario;

- an addition of at least one new DRB for the radio connection in a non-SA (NSA) deployment scenario;

- an addition of at least one secondary cell for carrier aggregation in the SA or NSA deployment scenario; and

- a configuration of scenario-dependent channel measurements for the radio connection. A user equipment (UE) for wireless communications, comprising: a processor; a memory coupled to the processor and configured to store processor-executable instructions; and a transceiver coupled to the processor; wherein the processor is configured, when executing the processor-executable instructions, to: cause the transceiver to send a UE notification to a Radio Access Network (RAN) node with which the UE has established a radio connection, the UE notification indicating that the UE supports a rollback of failed connection reconfigurations that relate to a predefined list of connection reconfigurations; cause the transceiver to receive, from the RAN node, a message about a connection reconfiguration to be performed for the radio connection, the connection reconfiguration relating to the predefined list of connection reconfigurations; if the connection reconfiguration fails to perform, roll back the failed connection reconfiguration. The UE of claim 7, wherein the processor is configured to cause the transceiver to send the UE notification in response to a rollback capability enquiry received by the transceiver from the RAN node. The UE of claim 7 or 8, wherein, if the connection reconfiguration fails to perform, the processor is further configured to generate a reconfiguration failure message and cause the transceiver to send the reconfiguration failure message to the RAN node. The UE of any one of claims 7 to 9, wherein the predefined list of connection reconfigurations comprises at least one of the following:

- a configuration of scenario-dependent channel measurements for the radio connection. A method for operating a Radio Access Network (RAN) node in a wireless communication network, comprising: preparing a connection reconfiguration for a radio connection established between a user equipment (UE) and the RAN node, the connection reconfiguration relating to a predefined list of connection reconfigurations; sending a message about the connection reconfiguration to the UE; 27 detecting that the UE has failed to perform the connection reconfiguration of the radio connection; checking whether the UE belongs to a predefined set of UEs configured to support a rollback of failed connection reconfigurations that relate to the predefined list of connection reconfigurations; and if the UE belongs to the predefined set of UEs, rolling back the failed connection reconfiguration for the radio connection. The method of claim 11, further comprising, if the UE is absent in the predefined set of UEs, re-establishing the radio connection. The method of claim 11 or 12, wherein the predefined set of UEs is obtained by:

- sending a rollback capability enquiry to all UEs that have established radio connections with the RAN node; and

- receiving UE notifications about whether the UEs support the rollback of failed connection reconfigurations that relate to the predefined list of connection reconfigurations. The method of any one of claims 11 to 13, wherein said detecting comprises detecting that the UE has failed to perform the connection reconfiguration in response to a reconfiguration failure message received from the UE. The method of any one of claims 11 to 13, wherein said detecting comprises detecting that the UE has failed to perform the connection reconfiguration if there is no reconfiguration complete message received from the UE within a predefined timer. The method of any one of claims 11 to 15, wherein the predefined list of connection reconfigurations comprises at least one of the following:

- an addition of at least one new Data Radio Bearer (DRB) for the radio connection in a standalone (SA) deployment scenario; 28

- a configuration of scenario-dependent channel measurements for the radio connection. A method for operating a user equipment (UE) in a wireless communications network, comprising: sending a UE notification to a Radio Access Network (RAN) node with which the UE has established a radio connection, the UE notification indicating that the UE supports a rollback of failed connection reconfigurations that relate to a predefined list of connection reconfigurations; receiving, from the RAN node, a message about a connection reconfiguration to be performed for the radio connection, the connection reconfiguration relating to the predefined list of connection reconfigurations; if the connection reconfiguration fails to perform, rolling back the failed connection reconfiguration for the radio connection. The method of claim 17, wherein said sending the UE notification is performed in response to a rollback capability enquiry received from the RAN node. The method of claim 17 or 18, further comprising, if the connection reconfiguration fails to perform, generating a reconfiguration failure message and sending the reconfiguration failure message to the RAN node. The method of any one of claims 17 to 19, wherein the predefined list of connection reconfigurations comprises at least one of the following:

- an addition of at least one new DRB for the radio connection in a non-SA (NSA) deployment scenario; 29

- a configuration of scenario-dependent channel measurements for the radio connection. A computer program product storing a computer-readable storage medium, wherein the computer-readable storage medium comprises a computer code which, when executed by a processor, causes the processor to perform the method according to claim 11. A computer program product storing a computer-readable storage medium, wherein the computer-readable storage medium comprises a computer code which, when executed by a processor, causes the processor to perform the method according to claim 17.