WO2023186253A1

WO2023186253A1 - Method and apparatus for network slice management

Info

Publication number: WO2023186253A1
Application number: PCT/EP2022/058042
Authority: WO
Inventors: Alessio Casati; Philippe Godin
Original assignee: Nokia Technologies Oy
Priority date: 2022-03-28
Filing date: 2022-03-28
Publication date: 2023-10-05
Also published as: CN118614110A

Abstract

Disclosed is inter alia a method comprising: - obtaining, by a first network node, at least one requested network slice selection assistance information, NSSAI; and - providing, by the first network node, a first message, at least partially based on the obtained requested NSSAI, wherein the first message comprises a radio resource management, RRM, preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSAI and/or a radio access technology frequency selection priority, RFSP, associated with the at least one target NSSAI in a second network node to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI to drive a radio resource management in the second network node.

Description

METHOD AND APPARATUS FOR NETWORK SLICE MANAGEMENT

Technical field

Various exemplary embodiments according to the present disclosure relate to network slicing of communication networks. Specifically, various exemplary embodiments according to the present disclosure relate to slice management based on target network slice selection assistance information (NSSA1).

Background

Various exemplary embodiments according to the present disclosure are related but not limited to communication networks as defined by the 3GPP (3rd Generation Partnership Project) standard, such as the 5G standard, also referred to as New Radio (NR).

Network slicing is a key 5G feature to support different services using the same underlying mobile network infrastructure. For example, a network slice may be understood as a logical network that provides specific network capabilities and network characteristics in order to serve a defined business purpose of a customer. In order to benefit from such slice-specific network services, a user device may for example need to register to a specific network slice as part of a registration process.

However, support for network slicing in the 5G radio access network (RAN) was initiated by the 3GPP only recently. Accordingly, in order to support network slicing in the 5G system, several problems and challenges need to be solved.

Summary of some exemplary embodiments

Certain embodiments may for example be directed to providing radio resource management (RRM) preference information associated with at least one target NSSA1. Radio resource management may then for example be at least partially based on such RRM preference information. According to a first aspect of the present disclosure, a method is disclosed, wherein the method comprises: obtaining, by a first network node, at least one requested NSSA1; and providing, by the first network node, a first message, at least partially based on the obtained requested NSSA1, wherein the first message comprises a radio resource management, RRM, preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSA1 and/or a radio access technology frequency selection priority, RFSP, associated with the at least one target NSSA1 in a second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node.

Further according to the first aspect of the present disclosure, a first network node is disclosed, wherein the first network node comprises at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the first network node at least to perform: obtaining at least one requested NSSA1; and providing a first message, at least partially based on the obtained requested NSSA1, wherein the first message comprises an RRM preference information, wherein the RRM preference information is indicative of whether to store a target NSSA1 in a second network node and/or to use the RRM preference information at least partially based on a related RFSP indicated by the RRM preference information.

According to a second aspect of the present disclosure, a method is disclosed, wherein the method comprises: obtaining, by a second network node, a first message, wherein the first message comprises an RRM preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSA1 and/or an RFSP associated with the at least one target NSSAI in the second network node to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI to drive a radio resource management in the second network node.

Further according to the second aspect of the present disclosure, a second network node is disclosed, wherein the second network node comprises at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the second network node at least to perform: obtaining a first message, wherein the first message comprises an RRM preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSAI and/or an RFSP associated with the at least one target NSSAI in the second network node to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI to drive a radio resource management in the second network node.

For example, the first network node may be a core network (CN) node. A core network node may for example be understood as an entity or function of a communication network of any generation. Generally, a core network node may for example be or comprise a hardware or software component implementing a certain functionality. Accordingly, while a core network node may be understood to be implemented in or be a single device or module, the core network node may also be implemented across or comprise multiple devices or modules. In particular, a core network node may be understood as network function and/or network entity as defined by the 3GPP 5G or NR standard (see e.g. 3GPP TS 23.501 for further details on the system architecture for the 5G system). Accordingly, the 5G system architecture may comprise an access and mobility management function (AMF), a session management function (SMF), a network slice selection function (NSSF), a policy control function (PCF) and/or further functions or entities. In particular, the first network node may for example provide (e.g. serve as, implement, control, comprise and/or be) an AMF, which may for example handle control signaling between a core network and one or more user devices and/or one or more RAN nodes, security for user data, idle-state mobility, and/or authentication. The functionality operating between a core network, for example more specifically the AMF, and one or more user devices may be referred to as the non-access stratum (NAS), to for example separate it from the access stratum (AS), which handles functionality operating between one or more user devices and the RAN.

The second network node may for example be an electronic device, such as a node of a network of a communication system. For example, the second network node may be a RAN node. A RAN node may for example be understood as a wireless communication station installed at a fixed or mobile location and may for example be a communication station of any generation (e.g. a gNB, eNodeB, NodeB, BTS or the like) of the 3GPP standard. Generally, a RAN node may be or comprise a hardware or software component implementing a certain functionality. In an example, a RAN node may be base station as defined by the 3GPP 5G or NR standard (also referred to as gNB).

Accordingly, while a RAN node may be understood to be implemented in or be a single device or module, a RAN node may also be implemented across or comprise multiple devices or modules. As such, a RAN node may in particular be implemented in or be a stationary device. Multiple RAN nodes may in particular establish a communication system or RAN, which may in particular be an NR or 5G system or any other mobile communications system defined by a past or future standard, in particular successors of the present 3GPP standards. A RAN node may be capable of being in direct and/or indirect communication with one or more user devices and/or with one or more further RAN nodes and/or with one or more core network nodes.

Referring to one or more RAN nodes and one or more core network nodes, these nodes may be capable of being in direct and/or indirect communication with each other. According to the 5G architecture, a RAN node (e.g. a gNB) may for example be connected to the 5G core network by means of the NG interface, while the Xn interface may for example connect several gNBs to each other.

For example, the first network node may comprise means for performing the method disclosed herein according to the first aspect of the present disclosure. Further, the second network node may comprise means for performing the method disclosed herein according to the second aspect of the present disclosure. The means of any of the disclosed network nodes can for example be implemented in hardware and/or software. They may for example comprise one or multiple modules or units providing the respective functionality. They may for example comprise at least one processor for executing computer program code for performing the required functions, at least one memory storing the program code, or both. Alternatively, they could comprise for example circuitry that is designed to implement the required functions, for example implemented in a chipset or a chip, like an integrated circuit. In general, the means may comprise for example one or more processing means or processors.

Any of the above-disclosed network nodes may be a module or a component for a device, for example a chip. The disclosed network nodes may comprise the disclosed components, for example means, processor, memory, or may further comprise one or more additional components.

The method of a respective aspect of the present disclosure may for example be performed and/or controlled by the network node according to the respective aspect, i.e. the first network node or the second network node, respectively. Generally, however, a respective method may also be performed and/or controlled by more than one apparatuses, for example by one or more network nodes working together.

According to the first aspect and second aspect of the present disclosure, there is in each case also disclosed a computer program, the computer program when executed by a processor of a network node causing said network node to perform a method according to the first or second exemplary aspect respectively. The computer program may for example be stored on a computer-readable storage medium, in particular a tangible and/or non-transitory medium. The computer readable storage medium could for example be a disk or a memory or the like. The computer program could be stored in the computer readable storage medium in the form of instructions encoding the computer-readable storage medium. The computer readable storage medium may for example be intended for taking part in the operation of a device, like an internal or external memory, for example a Read-Only Memory (ROM) or hard disk of a computer, or be intended for distribution of the program, like an optical disc. For example, a non-transitory computer readable medium may comprise program instructions for causing a network node to perform a method according to the first or second aspect respectively.

There is also disclosed a system comprising at least a first network node according to the first exemplary aspect of the present disclosure and a second network node according to the second exemplary aspect of the present disclosure. In further examples, the disclosed system may further comprise one or more further network nodes (e.g. one or more further core network nodes and/or one or more further RAN nodes) and/or one or more user devices (e.g. one or more user devices communicating with the first and/or second network node).

Obtaining, by a first network node (e.g. a core network node providing an AMF), at least one requested NSSA1 may for example be understood to mean that the first network node receives at least one requested NSSA1 from a user device. In some examples, a user device signals at least one requested NSSA1 to the first network node, wherein the at least one requested NSSA1 may be included in a message (e.g. a registration message or a registration request) that is transmitted by the user device to the first network node. In some examples, a user device may provide a registration message including the least one requested NSSA1 in 5G-AN (5G access network) signaling and the 5G-AN may forward the registration message to the first network node. As an example, a registration request obtained by the first network node may comprise at least one requested NSSAI and optionally may additionally comprise information indicating a preference of the user device of privileging an allowed NSSAI or a target NSSAI.

For example, an NSSAI may comprise a plurality of single network slice selection assistance information (S-NSSA1), such that an NSSAI may for example be understood as a group (e.g. a collection or a list) of several S-NSSA1 (see e.g. 3GPP TS 23.501). Therein, an S-NSSA1 may for example be understood to identify a particular network slice and/or network slice instance. For example, an S-NSSA1 may be a parameter (e.g. an identifier) of a network slice and/or network slice instance and may as such comprise for example a mandatory slice/service type and an optional slice differentiator (wherein e.g. the slice differentiator differentiates network slices with the same mandatory slice/service type).

There may be various types of NSSAI including for example requested NSSAI, allowed NSSAI and target NSSAI. While some exemplary information on these types of NSSAI are given in the following, further details may also be described in the 3GPP 5G standard (see e.g. 3GPP TS 23.501).

For example, a requested NSSAI may be understood as NSSAI that is provided (e.g. signalled) by a user device to a network (e.g. one or more network nodes, e.g. a core network node providing an AMF). In particular, the requested NSSAI may for example indicate (e.g. contain) one or more S-NSSA1 identifying respective network slices to which a user device wishes (e.g. requests) to register.

In further examples, allowed NSSAI may be understood as NSSAI determined by a network (e.g. one or more network nodes, e.g. a core network node providing an AMF) and may for example be returned to the user device and/or one or more network nodes (e.g. one or more RAN nodes) in response to providing a requested NSSAI by the user device. For example, an allowed NSSAI may indicate (e.g. contain) one or more S-NSSA1 identifying respective network slices to which a user device is allowed to register or which a user device is allowed to use. For example, a target NSSAI may be understood as a set of S-NSSAI that is determined by the core network (e.g. one or more core network nodes) in case that at least some S- NSSA1 of the requested NSSAI requested by a user device may not be supported by a tracking area (TA) where a user device is located in. Accordingly, the core network may for example determine a target NSSAI and provides this target NSSAI to the RAN, such that for example the RAN may redirect a user device to a tracking area (e.g. in the neighboring cells) supporting the target NSSAI.

To give another non-limiting example, a particular network slice identified by an S- NSSA1 may be configured to be available only in tracking areas covering specific dedicated frequency bands, such that there may for example be a need to redirect the user device to the corresponding dedicated frequency bands when for example such S- NSSA1 is requested by a user device. If for example a requested NSSAI contains S- NSSAl(s) that are not available in the user device’s current tracking area, the core network (e.g. an AMF) may determine a target NSSAI to be used by the RAN in order to attempt to redirect the user device to a cell in another frequency band and tracking area that supports the S-NSSAls in the target NSSAI. For example, the target NSSAI may include at least one S-NSSAI from the requested NSSAI, which may not be available in the current tracking area, but may be available in another tracking area (e.g. in a different frequency band) that for example overlaps with the current tracking of the user device.

For example, an NSSAI may be associated with a radio access technology frequency selection priority (RFSP) as defined in 3GPP TS 23.401. Such an RFSP may for example allow a mobile operator to give a user device specific instructions as to how the various different access networks are to be used. In some examples, this may be understood to mean that for example an RFSP to which a target NSSAI is associated may be different from an RFSP to which an allowed NSSAI is associated. For example, an RFSP may indicate (e.g. include, represent or be) an RFSP index which may for example refer to a user device information used by the RAN in order to apply specific radio resource management strategies. Considering for example a target and allowed NSSAI as described above, an RFSP index associated to the target NSSAI is for example considered if the RAN succeeds to redirect the UE to a new tracking area, while otherwise for example an RFSP index of an allowed NSSAI is considered.

Considering an RFSP that may be associated with at least one target NSSAI (e.g. a plurality of target NSSAI), it may be understood to mean that a respective RFSP is associated with at least one (e.g. some, each or all) of the at least one target NSSAI (e.g. of the plurality of target NSSAI). For example, it may be that an RRM preference information is indicative of whether to store a plurality of (e.g. more than one) target NSSAI and/or respective RFSP associated with the plurality of (e.g. more than one) target NSSAI in a second network node to use the plurality of (e.g. more than one) NSSAI and/or the respective RFSP associated with the plurality of (e.g. more than one) NSSAI to drive a radio resource management in the second network node. In such examples considering respective RFSP associated with for example two (or more) target NSSAI, it may be understood that one respective RFSP may be associated with a first target NSSAI of the two (or more) target NSSAI and that one other respective RFSP may be associated with a second target NSSAI of the two (or more) target NSSAI.

Providing a first message by the first network node (e.g. a core network node providing an AMF) at least partially based on the obtained at least one requested NSSAI may for example be understood to mean that providing the first message may at least partially depend on obtaining the at least requested NSSAI. For example, a first message may be provided in response to obtaining the requested NSSAI. In some examples, the step of providing the first message may comprise determining the first message at least partially based on the obtained at least one requested NSSAI. This may for example include determining the RRM preference information included in the first message and/or determining at least one target NSSAI, at least one allowed NSSAI and/or an RFSP associated with the at least one target NSSAI.

In some examples, in addition to obtaining at least one requested NSSAI by the first network node, information indicating a preference of a user device (e.g. of privileging an allowed NSSA1 or a target NSSA1) may be obtained by the first network node. In such an example, providing by the first network node, a first message may at least partially be based on the obtained requested NSSA1 and additionally on an information indicating a preference of a user device (e.g. of privileging an allowed NSSA1 or a target NSSA1) as obtained by the first network node.

In some examples, providing the first message by the first network node may be understood to mean that the first message is transmitted to another network node (e.g. the second network node, which is e.g. a RAN node).

For example, a radio resource management (RRM) preference information may be understood as any type of information (e.g. one or more pieces or items of information and/or one or more parameters) that is suitable for indicating whether to store at least one target NSSA1 and/or an RFSP (e.g. one or more RFSP indices) associated with the at least one target NSSA1 in a second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node.

For example, whether to store at least one target NSSA1 and/or a RFSP may be explicitly or implicitly indicated by the first message. For example, if the RRM preference information is included in the first message, it may implicitly indicate to store the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1. In another example, an explicit indicator may also be included in the first message and the indicator may for example instruct the first network node to store the at least one target NSSA1 and/or RFSP.

Storing at least one target NSSA1 and/or an RFSP (e.g. one or more RFSP indices) associated with the at least one target NSSA1 in a second network node to (e.g. in order to) use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node may be understood to mean that the at least one target NSSA1 and/or an RFSP (e.g. one or more RFSP indices) associated with the at least one target NSSAI may be stored in (e.g. at or by) a second network node (e.g. a RAN node to which the first message is provided) with the purpose of (e.g. in order to) using the at least one target NSSAI and/or the RFSP (e.g. one or more RFSP indices) associated with the at least one target NSSAI when driving a radio resource management in the second network node. Therein, storing (e.g. in a UE context) the RRM preference information may for example comprise storing the RRM preference information in an electronic memory of the second network node (e.g. an electronic memory of a RAN node to which the first message is provided).

Using at least one target NSSAI and/or an RFSP associated with the at least one target NSSAI to drive a radio resource management in (e.g. at or by) the second network node may for example be understood to mean that driving a radio resource management in (e.g. at or by) the second network node may at least partially be based on the at least one target NSSAI and/or an RFSP associated with the at least one target NSSAI. For example, driving a radio resource management in the second network node may refer to examples where the second network node (e.g. a RAN node) may perform driving a radio resource management. Therein, driving a radio resource management may for example be understood to mean that a radio resource management is processed, determined, controlled and/or performed.

In more general examples, radio resource management may for example be understood as system level management of for example co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless local area networks, wireless sensor systems, and/or radio broadcasting networks. For example, radio resource management may involve strategies and/or algorithms for controlling parameters such as transmit power, user allocation, beamforming, data rates, hand over criteria, modulation scheme, error coding scheme and others in order to utilize radio-frequency spectrum resources and radio network infrastructure efficiently. Considering driving a radio resource management in the second network node, the second network node may for example use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 for managing radio resources, which may for example be radio resources related to one or more user devices (e.g. at least a user device from which the at least one requested NSSA1 is obtained by the first network node). To give some non-limiting examples, driving radio resource management in the second network node may comprise redirecting and/or handing over a user device to a particular network cell of a tracking area of a RAN (e.g. a RAN to which the second network node belongs), wherein this other network cell may be part of a different tracking area than the network cell to which the user device was previously connected (e.g. before redirecting and/or handing over the user device). For example, driving a radio resource management in the second network node at least partially based on at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 may be understood to mean that driving the radio resource management may comprise redirecting and/or handing over a user device to a particular network cell (e.g. a network cell of a tracking area) supporting the at least one target NSSA1.

Referring to the method disclosed above according to the second aspect of the present disclosure, obtaining, by a second network node (e.g. a RAN node), a first message may be understood to mean that the first message may be received, by the second network node, from the first network node (e.g. a core network node providing an AMF) providing the first message according to the first aspect of the present disclosure.

According to an exemplary embodiment of the second aspect, the method further comprises at least one of: storing, by the second network node, at least one target NSSA1 and/or an RFSP associated with (e.g. each of) the at least one target NSSA1 in the second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node; using, by the second network node, the at least one target NSSAI and/or the RFSP associated with (e.g. each of) the at least one target NSSAI to drive a radio resource management in the second network node; or driving, by the second network node, a radio resource management in the second network node, for example at least partially based on the at least one target NSSAI and/or the RFSP associated with (e.g. each of) the at least one target NSSAI.

For example, providing RRM preference information indicating whether to store at least one target NSSAI and/or an RFSP associated with the at least one target NSSAI in a second network node to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI to drive a radio resource management in the second network node may have the effect that the radio resource management may be improved. In some examples, a first network node (e.g. a core network node providing an AMF) may provide RRM preference information to a second network node (e.g. a RAN node), such that the second network node may be enabled to drive radio resource management based on the RRM preference information. For example, the second network node may be enabled to determine at least partially based on the RRM preference information whether a radio resource management based on an allowed NSSAI or based on a target NSSAI is to be driven.

In some examples, considering the first network node as AMF and the second network node as RAN node, the AMF may provide at least one target NSSAI to the RAN and may additionally provide RRM preference information associated with the target NSSAI, such that the RAN may decide (e.g. autonomously without need of any further subsequent AMF trigger) whether to store the target NSSAI at the RAN (e.g. in a UE context) and whether to apply the radio resource management based on the target NSSAI and the RFSP associated with the target NSSAI (e.g. instead of using an allowed NSSAI for radio resource management). According to an exemplary embodiment of the first or second aspect, the RRM preference information further indicates at least one of: whether to use (e.g. in the second network node) the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 or, instead, at least one allowed NSSA1 and/or an RFSP associated with (e.g. each of) the at least one allowed NSSA1 after a failure to redirect and/or handover a user device to a cell in a tracking area, TA, supporting the target NSSA1; a time validity of the at least one target NSSA1 and/or the RFSP associated with (e.g. each of) the at least one target NSSA1; a validity of the at least one target NSSA1 for a TA, a network cell and/or a list of TAs; a priority order of the target NSSA1; or one or more alternative target NSSA1.

For example, the RRM preference information may indicate (e.g. represent) whether to use the at least one target NSSA1 and/or the RFSP associated with (e.g. each of) the at least one target NSSA1 or, instead, whether to use at least one allowed NSSA1 and/or an RFSP associated with (e.g. each of) the at least one allowed NSSA1 after a failure to redirect and/or hand over a user device to a cell in a tracking area supporting the target NSSA1. In some examples, the RRM preference information may for example indicate (e.g. represent) whether to use the at least one target NSSA1 and/or the respective RFSP associated with (e.g. each of) the at least one target NSSA1 in (e.g. at or by) the second network node (e.g. a second network node to which a first message comprising the RRM preference information is provided).

In some examples, a RAN node may redirect or hand over a user device to a cell in a tracking area supporting a target NSSA1, but this redirecting or handing over may fail due to a lack of coverage of the cell in the tracking area supporting the target NSSA1 at the current position of the user device. Assuming that for example the user device then changes its position such that coverage of the cell in the tracking area supporting the target NSSA1 becomes available at the position of the user device, it may be possible for the RAN to again perform redirecting or handing over the user device to a cell in a tracking area supporting a target NSSA1 or, instead perform redirecting or handing over a user device to a cell in a tracking area supporting an allowed NSSA1. Considering these exemplary options, the RRM preference information may be indicative of whether to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 or, instead, to use at least one allowed NSSA1 and/or an RFSP associated with the at least one allowed NSSA1.

For example, it shall be understood that a tracking area refers to a group of network cells which are for example provided by a particular RAN node. Tracking areas may for example be understood as basis for tracking a user device. To that purpose, a user device may be assigned to a respective registration area (e.g. by the core network) consisting of a list of tracking area identifiers. For example, when a user device enters a network cell that belongs to a tracking area not included in a registration area assigned to the user device, the user device may access the core network and perform a non- access stratum (NAS) registration update.

In another example, the RRM preference information may indicate (e.g. represent) a time validity of the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1.

For example, a time validity of the at least one target NSSA1 may be understood as time period, after which for example the at least one target NSSA1 may be removed from the second network node (e.g. removed from an electronic memory of the second network node) and radio resource management may for example be resumed to be based on an allowed NSSA1 and an RFSP associated with the allowed NSSA1.

In another example, a time validity indicated by the RRM preference information may be understood as time validity for storing and/or using the at least one target NSSA1 and/or the RFSP associated with (e.g. each of) the at least one target NSSA1 in (e.g. by or at) the second network node (e.g. a second network node to which a first message comprising the RRM preference information is provided).

In another example, the RRM preference information may indicate (e.g. represent) a validity of the at least one target NSSAI for a TA, a network cell and/or a list of TAs.

For example, when the RRM preference information may indicate a validity (e.g. an area validity) of the at least one target NSSAI for a tracking, a network cell and/or a list of tracking areas, this may be understood to mean that the RRM preference information may indicate whether the at least one target NSSAI may be valid for (e.g. apply to) a tracking area, a network cell and/or a list of tracking areas.

For example, the at least one target NSSAI may be considered valid for (e.g. apply to) a tracking area if the tracking area may support the at least one target NSSAI (e.g. if the at least one target NSSAI is available at the tracking area and/or e.g. if a user device located in the tracking area may be able to register to the at least one target NSSAI). As further example, the at least one target NSSAI may be considered valid for a network cell if the network cell may support the at least one target NSSAI (e.g. if the at least one target NSSAI is available at the network cell and/or e.g. if a user device located in the network cell may be able to register to the at least one target NSSAI).

In some examples, a validity (e.g. an area validity) of the at least one target NSSAI for a tracking area, a network cell and/or a list of tracking areas indicated by an RRM preference information may be understood as a validity (e.g. an area validity) for using the at least one target NSSAI for a tracking area, a network cell and/or a list of tracking areas in (e.g. by or at) the second network node (e.g. a second network node to which a first message comprising the RRM preference information is provided).

In another example, the RRM preference information may indicate (e.g. represent) a priority order of the at least one target NSSAI. Referring for example to a plurality of target NSSAI, a priority order may be understood as priority order of the plurality of target NSSAI such that for example the second network node (e.g. a RAN node) may for example attempt first use a target NSSAI of the plurality of target NSSAI with a higher (e.g. the highest) priority for radio resource management. This example may apply if for example the RRM preference information may indicate not to store the at least one target NSSAI in the second network node.

In another example, the RRM preference information may indicate (e.g. represent) one or more alternative target NSSAI. For example, a list of alternative target NSSAI may refer to target NSSAI in alternative to the at least one target NSSAI. For example, such alternative target NSSAI may be applied by the second network node (e.g. a RAN node) immediately after obtaining and/or at a particular point in time. For example, a respective alternative target NSSAI may be associated with a respective RRM preference information in a manner as disclosed above.

It may further be understood that in some examples, the RRM preference information may indicate at least one of the following: one or more alternative target NSSAI; one or more respective alternative RFSP (e.g. which are respectively associated with the one or more alternative target NSSAI); one or more respective time validities of the one or more alternative target NSSAI (e.g. one respective time validity of each of the one or more alternative target NSSAI); one or more respective validities (e.g. area validities) of the one or more alternative target NSSAI for a tracking area, a network cell and/or a list of tracking areas.

According to an exemplary embodiment of the first aspect, the method further comprises: transmitting, by the first network node, the first message to the second network node. For example, the first network node may be considered as a core network node providing an AMF, such that the AMF may then perform transmitting the first message to the second network node, wherein the second network node may for example be understood as RAN node. The first message may then for example be obtained at the RAN node. For example, the first message may be understood as an NG-AP message that includes the at least one target NSSA1 as well as an RRM preference information associated with the target NSSA1.

In some example, the first message transmitted to the second network node by the first network node may further (e.g. in addition to the RRFM preference information) comprise at least one of the following: the at least one target NSS1A; an RFSP associated with the at least one target NSSA1.

According to an exemplary embodiment of the first or second aspect, the first message further (e.g. in addition to the RRFM preference information) comprises at least one of: the at least one target NSSA1; the at least one allowed NSSA1; or the RFSP associated with the at least one target NSSA1.

For example, considering that the first message may further (e.g. in addition to the RRFM preference information) comprise the at least one target NSSA1, the at least one target NSSA1 may be determined by the first network node, for example at least partially based on the requested NSSA1 obtained by the first network node. As another example, considering that the first message may comprise the at least one allowed NSSA1, the at least one allowed NSSA1 may be determined by the first network node, for example at least partially based on the requested NSSA1 obtained by the first network node. As another example, considering that the first message may comprise the RFSP associated with the at least one target NSSA1, the RFSP associated with the at least one target NSSA1 may be determined by the first network node, for example at least partially based on the requested NSSA1 obtained by the first network node. In some example, the first message may comprise a plurality of target NSSAI. In such a case, the first message may further comprises the respective RFSP associated with at least one (e.g. some or each) of the plurality of target NSSAI.

According to an exemplary embodiment of the first aspect, the method further comprises: triggering, by the first network node, a request or update to a third network node, wherein the request or update indicates RRM preference support.

According to an exemplary embodiment of the first aspect, the method further comprises: receiving a second message from the third network node, wherein the second message comprises the RRM preference information.

For example, the first network node (e.g. a core network node providing an AMF) may trigger a request or update (e.g. by transmitting a request message or an update message) to a third network node, wherein the third network node may for example understood as another core network node (e.g. a core network node providing an PCF). The request or update may indicate RRM preference support, for example by including an RRM preference support information indicating that the first network node may require support in determining an RRM preference information associated with at least one target NSSAI. In some examples, the request or update may additionally indicate (e.g. include) at least one target NSSAI in association to which an RRM preference information is requested.

For example, after (e.g. in response to or in reaction to) triggering a request or update to a third network node (e.g. a core network node providing an AMF), the first network node may receive a second message from the third network node (e.g. the core network providing an PCF to which the first network node triggered the request or update). The second message may then for example at least comprise the RRM preference information for which the RRM preference support is indicated in the request or update. In addition, the second message may further comprise an RFSP associated with the at least one target NSSAI to which the RRM preference information included in the second message is associated.

It is to be understood that the presentation of the embodiments disclosed herein is merely by way of examples and non-limiting.

Herein, the disclosure of a method step shall also be considered as a disclosure of means for performing the respective method step. Likewise, the disclosure of means for performing a method step shall also be considered as a disclosure of the method step itself.

Other features of the present disclosure will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the present disclosure, for which reference should be made to the appended claims. It should be further understood that the drawings are not drawn to scale and that they are merely intended to conceptually illustrate the structures and procedures described herein.

Brief description of the figures

In the following, various exemplary embodiments will be described in greater detail with reference to the accompanying drawings, in which

Fig. 1 shows an exemplary environment in which exemplary embodiments of the various aspects of the present disclosure may be performed;

Fig. 2 shows a flow diagram of an exemplary embodiment of a method according to the first aspect of the present disclosure; Fig. 3 shows a flow diagram of an exemplary embodiment of a method according to the second aspect of the present disclosure;

Fig. 4 shows a block diagram of an exemplary embodiment of a first network node according to the first aspect of the present disclosure;

Fig. 5 shows a block diagram of an exemplary embodiment of a second network node according to the second aspect of the present disclosure;

Fig. 6 shows an exemplary signaling chart illustrating an exemplary embodiment according to the various aspects of the present disclosure;

Fig. 7 shows another exemplary signaling chart illustrating an exemplary embodiment according to the various aspects of the present disclosure; and

Fig. 8 shows a schematic illustration of examples of tangible and non-transitory computer-readable storage media.

DETAILED DESCRIPTION OF THE FIGURES

The following description serves to deepen the understanding of the present disclosure and shall be understood to complement and be read together with the description of exemplary embodiments of the present disclosure as provided in the above summary section of this specification.

While the specific radio system in the examples below is 5G, this is only to be considered a non-limiting example.

Fig. 1 shows a schematic illustration of an exemplary environment 100 in which exemplary embodiments of the various aspects of the present disclosure may be performed.

Without limiting the scope of the present disclosure, it may be assumed in the following that a user device which is also called as user equipment (UE) 110 as user device is located and changes its position over time within a spatial environment 100. For example, UE 110 may be understood as mobile device (e.g. a mobile terminal), such as a smart phone, a tablet, a wearable, a smartwatch, a low power device, an loT device or the like.

Generally, UE 110 may also be understood as any other device enabled for communication with a respective communication network (e.g. a communication network as defined by the 3GPP 5G standard), such as a vehicle, for example a car. In other examples, UE 110 may be understood as any device used to communicate with a respective network (e.g. a communication network as defined by the 3GPP 5G standard). For example, UE 110 may be in direct or indirect communication with one or more further user devices and/or with one or more RAN nodes 120, 130, 140, 150.

For example, environment 100 may include a plurality of RAN nodes 120, 130, 140, 150, wherein it may be assumed without limiting the scope of the present disclosure that RAN nodes 120, 130, 140, 150 may be respective base stations (e.g. a gNodeB/gNB, eNodeB/eNB, BS, access node, access point, or the like) of a cellular communication system like a 2G/3G/4G/5G or future generation cellular communication system or in communication with such a base station and as such may be referred to as gNB2a 120, gNB2b 130, gNBla 140 and gNBlb 150. For example, gNB2a 120, gNB2b 130, gNBla 140 and gNBlb 150 as RAN nodes may be in direct and/or indirect communication with each other and may further be in direct and/or indirect communication with one or more core network nodes and/or one or more core network entities (not shown in Fig. 1)-

According to the 5G architecture, gNB2a 120, gNB2b 130, gNBla 140 and gNBlb 150 may be connected to the 5G core network by means of the NG interface, while the Xn interface may connect several gNBs to each other. For example, one or more core network nodes may provide (e.g. control) an access and mobility management function (AMF), a session management function (SMF), a policy control function (PCF) and/or further functions or entities. In particular with respect to environment 100, a core network node may be understood as AMF, which may for example handle control signaling between the core network and UE 110, security for user data, idle-state mobility, and authentication.

It may be assumed as an example that gNBla 140 and gNBlb 150 may provide (e.g. control) one or more respective network cells cellll-Fl, celll2-Fl, celll3-Fl and celll4- F1 in a frequency layer Fl. These network cells may for example be part of (e.g. belong to or form) a respective tracking area 1 and/or registration area 1 (e.g. registration area 1 may be understood as list of one or more tracking areas including tracking area 1). For example, such registration area 1 may support a specific network slice identified by a parameter S-NSSA11 (e.g. network slice S-NSSA11 may be available in the registration area 1). It may be assumed as an example in the following that network slice S-NSSA11 and/or registration area 1 are related to a smart factory deployment.

It may further be assumed as an example that gNB2a 120 and gNB2b 130 may provide (e.g. control) one or more respective network cells cell21-F2, cell22-F2, cell23-F2 and cell24-F2 in a frequency layer F2. These network cells may for example be part of (e.g. belong to or form) a respective tracking area 2 and/or registration area 2 (e.g. registration area 2 may be understood as list of one or more tracking areas including tracking area 2). For example, such registration area 2 may support a specific network slice identified by a parameter S-NSSA12 (e.g. network slice S-NSSA12 may be available in the registration area 2). It may be assumed as an example in the following that network slice S-NSSA12 and/or registration area 2 are related to a macro deployment.

Further referring to the exemplary environment 100 shown in Fig. 1, at a given point of time tO, UE 110 may for example be connected to one of the network cells provided by gNB2a (e.g. UE 110 may be served by gNB2a) and may further use services of network slice S-NSSA12. As UE 110 may be located near the smart factory deployment in environment 100, UE 110 may request access to network slice S-NSSA11 belonging to registration area 1 related to the smart factory deployment. For example, such a request may be part of a registration message provided by UE 110 to the AMF. For example, in response to the request by UE 110, the core network (e.g. the AMF] may issue a service request rejection for S-NSSAI1. Furthermore, the AMF may for example determine a target NSSA1 (including S-NSSA11] and an RFSP associated with S-NSSA11 and further may signal the target NSSA1 and the RFSP to gNB2a 120 serving UE 110.

Further referring to the exemplary environment 100 shown in Fig. 1, at a given point of time tl after point of time tO, UE 110 may for example still be connected to one of the network cells provided by gNB2a (e.g. UE110 may be served by gNB2a). Further, UE 110 may for example be located outside of the coverage of network cells cellll-Fl, celll2-Fl, celll3-Fl and/or celll4-Fl provided by gNBla 140 and/or gBN lb 150 and as such may be outside of the coverage of registration area 2 supporting network slice S- NSSA11. In this example, it follows that gNB2a may be unable to redirect UE 110 as instructed by the AMF at tO due to lack of coverage.

Further referring to the exemplary environment 100 shown in Fig. 1, at a given point of time t2 after point of time tl, UE 110 may have changed its position within environment 100 such that UE 110 may for example be located inside of the coverage of network cells cellll-Fl, celll2-Fl, celll3-Fl and/or celll4-Fl provided by gNBla 140 and/or gBNlb 150 and as such may be inside of the coverage of registration area 2 supporting network slice NSSA11.

Further, UE 110 may be changed its position closer to gNB2b 130 such that a hand over event of UE 110 to gNB2b 130 may have occurred. As such, UE 110 may for example not be allowed to request the network slice S-NSSA11 anymore. Since UE 110 changed its position into the coverage of registration area 2 supporting network slice S-NSSA11, it would for example be possible to redirect UE 110 to a respective network cell cellll-Fl, celll2-Fl, celll3-Fl and/or celll4-Fl of registration area 2 supporting network slice S- NSSA11.

However, gNB2b 130 does not have the target NSSA1 including S-NSSA11 available. As result, UE 110 may not be redirected to the smart factory deployment. Assuming that for example the target NSSAI including S-NSSA11 would be available at gNB2b 130, gNB2b 130 would be able to redirect UE 110 accordingly.

However, UE 110 may have ongoing sessions in the coverage layer in network slice S- NSSA12 that UE 110 started using when it could not access network slice S-NSSA11. Accordingly, storing the target NSSAI (e.g. the target NSSAI including S-NSSA11) in the RAN (e.g. in gNB2a 120 and/or gNB2b 130) may therefore lead to abrupt losses of ongoing sessions (e.g. even if at the time t2 when UE 110 moves to gNB2b 130, UE 110 would no longer be interested in using services of network slice S-NSSA12).

Fig. 2 shows a flow diagram 200 illustrating an exemplary embodiment of a method according to the first aspect of present disclosure. Without limiting the scope of the present disclosure, it may be assumed in the following that a first network node as depicted in Fig. 4 may perform the actions/steps of flow diagram 200.

Action 210 may comprise obtaining, by a first network node (e.g. a core network node providing an AMF), at least one requested NSSAI. For example, the first network node may be a first network node 400 as described below with respect to Fig. 4. To give a non-limiting example with respect to Fig. 6 as described below, the first network node may for example be understood as AMF 630, wherein AMF 630 obtains at least one requested NSSAI from UE 610.

Following action 210, action 220 may comprise providing, by the first network node, a first message, at least partially based on the obtained requested NSSAI, wherein the first message comprises a radio resource management, RRM, preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSAI and/or a radio access technology frequency selection priority, RFSP, associated with the at least one target NSSAI in a second network node to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI to drive a radio resource management in the second network node. For example, whether to store at least one target NSSA1 and/or an RFSP may be explicitly or implicitly indicated by the first message. For example, if the RRM preference information is included in the first message, it may implicitly indicate to store the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1. In another example, an explicit indicator may also be included in the first message and the indicator may for example instruct the first network node to store the at least one target NSSA1 and/or RFSP.

For example, the second network node may be a second network node 500 as described below with respect to Fig. 5. To give a non-limiting example with respect to signaling chart 600 in Fig. 6 as described below, the first network node may for example be understood as AMF 630, wherein AMF 630 provides at least one target NSSA1 and an RRM preference information associated with the at least one target NSSA1 together with an RFSP associated with the at least one target NSSA1 to RAN 620 as second network node. In this example, the first message may be understood as NG-AP message as transmitted in action 605 according to signaling chart 600.

Fig. 3 shows a flow diagram 300 illustrating an exemplary embodiment of a method according to the second aspect of present disclosure. Without limiting the scope of the present disclosure, it is assumed in the following that a second network node as depicted in Fig. 5 may perform the actions of flow diagram 300.

Action 310 may comprise obtaining, by a second network node, a first message, wherein the first message comprises an RRM preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSA1 and/or an RFSP associated with the at least one target NSSA1 in the second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node.

For example, the second network node may be a second network node 500 as described below with respect to Fig. 5. To give a non-limiting example with respect to signaling chart 600 in Fig. 6 as described below, the second network node may for example be understood as RAN 620, which obtains from AMF 630 as first network node at least one target NSSA1 and an RRM preference information associated with the at least one target NSSA1 together with an RFSP associated with the at least one target NSSA1. In this example, the first message may be understood as NG-AP message as transmitted in action 605 according to signaling chart 600.

Following action 310, one or more optional actions may be performed by the second network node. These one or more optional actions may for example comprise at least one of: storing, by the second network node, the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 in the second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive the radio resource management in the second network node; using the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive the radio resource management in the second network node; or driving the radio resource management in the second network node, for example at least partially based on the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1.

Referring to the respective methods illustrated in flow diagram 200 and flow diagram 300, providing RRM preference information indicating whether to store at least one target NSSA1 and/or an RFSP associated with the at least one target NSSA1 in a second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node may have the effect that the radio resource management may be improved.

In some examples, a first network node (e.g. a core network node providing an AMF) may provide RRM preference information to a second network node (e.g. a RAN node), such that the second network node may be enabled to drive radio resource management based on the RRM preference information. For example, the second network node may be enabled to determine at least partially based on the RRM preference information whether a radio resource management based on an allowed NSSA1 or based on a target NSSA1 is to be driven.

In some examples considering the first network node as AMF and the second network node as RAN node, the AMF may provide at least one target NSSA1 to the RAN and may additionally provide RRM preference information associated with the target NSSA1, such that the RAN may decide (e.g. autonomously without need of any further subsequent AMF trigger) whether to store the target NSSA1 at the RAN (e.g. in a UE context) and whether to apply the radio resource management based on the target NSSA1 and the RFSP associated with the target NSSA1 (e.g. instead of using an allowed NSSA1 for radio resource management).

For example, abrupt losses of ongoing sessions as described above with respect to Fig. 1 may be avoided by providing an RRM preference information indicating whether to store at least one target NSSA1 and/or an RFSP associated with the at least one target NSSA1 in a second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node.

Fig. 4 shows a block diagram of an exemplary embodiment of a first network node 400. For instance, network node 400 may be configured for scheduling and/or transmitting at least one of signals or messages to one or more user devices and/or to further network nodes as described above.

Network node 400 comprises a processor 401. Processor 401 may represent a single processor or two or more processors, which are for instance at least partially coupled, for instance via a bus. Processor 401 executes a program code stored in program memory 402, for instance program code causing network node 400 to perform alone or together with another network node (e.g. network node 500 as depicted in Fig. 5) and interfaces with a main memory 403.

Program memory 402 may also comprise an operating system for processor 401. Some or all of memories 402 and 403 may also be included into processor 401.

Moreover, processor 401 controls a communication interface 404 which is for example configured to communicate according to a cellular communication system like a 2G/3G/4G/5G/NR cellular communication system. Communication interface 404 of network node 400 may be provided for communication between network node and one or more further network nodes and/or one or more user devices.

The components 402 to 404 of network node 400 may for instance be connected with processor 401 by means of one or more serial and/or parallel busses.

It is to be understood that network node 400 may comprise various other components.

For example, first network node 400 may be a core network node. A core network node may be understood as an entity or function of a communication network of any generation. Generally, a core network node may be or comprise a hardware or software component implementing a certain functionality. Accordingly, while the core network node may be understood to be implemented in or be a single device or module, the core network node may also be implemented across or comprise multiple devices or modules.

In particular, a core network node may be understood as network function and/or network entity as defined by the 3GPP 5G or NR standard (see 3GPP TS 23.501). Accordingly, the 5G system architecture may comprise an access and mobility management function (AMF), a session management function (SMF), a network slice selection function (NSSF), a policy control function (PCF) and/or further functions or entities. In particular, network node 400 may for example provide (e.g. serve as, implement and/or control) an AMF, which may for example handle control signaling between the core network and one or more user devices, security for user data, idle-state mobility, and/or authentication. The functionality operating between the core network, for example more specifically the AMF, and one or more user devices may be referred to as the non-access stratum (NAS), to separate it from the access stratum (AS), which handles functionality operating between one or more user devices and the RAN.

Fig. 5 shows a block diagram of an exemplary embodiment of a second network node 500. For instance, network node 500 may be configured for scheduling and/or transmitting at least one of signals or messages to one or more user devices and/or to further network nodes as described above.

Network node 500 comprises a processor 501. Processor 501 may represent a single processor or two or more processors, which are for instance at least partially coupled, for instance via a bus. Processor 501 executes a program code stored in program memory 502 (for instance program code causing network node 500 to perform alone or together with another network node (e.g. network node 400 as depicted in Fig. 4) and interfaces with a main memory 503.

Program memory 502 may also comprise an operating system for processor 501. Some or all of memories 502 and 503 may also be included into processor 501.

Moreover, processor 501 controls a communication interface 504 which is for example configured to communicate according to a cellular communication system like a 2G/3G/4G/5G/NR cellular communication system. Communication interface 504 of network node 500 may be provided for communication between the network node and one or more further network nodes and/or one or more user devices.

The components 502 to 504 of network node 500 may for instance be connected with processor 501 by means of one or more serial and/or parallel busses. It is to be understood that network node 500 may comprise various other components.

For example, second network node 500 may be a RAN node. A RAN node may be understood as a wireless communication station installed at a fixed or mobile location and may for example be a communication network of any generation (e.g. a gNB, eNodeB, NodeB, BTS or the like) of the 3GPP standard. Generally, a RAN node may be or comprise a hardware or software component implementing a certain functionality. In an example, a RAN node may be base station as defined by the 3GPP 5G or NR standard (also referred to as gNB).

Referring to one or more RAN nodes and one or more core network nodes, these nodes may be capable of being in direct and/or indirect communication with each other. According to the 5G architecture, a RAN node (e.g. a gNB) may be connected to the 5G core network by means of the NG interface, while the Xn interface may connect several gNBs to each other.

Fig. 6 shows an exemplary signaling chart 600 illustrating an exemplary embodiment of the various aspects according to the present disclosure. For exemplary purposes and without limiting the scope of the present disclosure, it is assumed in the following that UE 610 (e.g. a user device as described above) is in direct or indirect communication with RAN 620 (e.g. one or more RAN network nodes as e.g. depicted in Fig. 5) and an AMF 630 (e.g. an AMF provided by one or more core network nodes as e.g. depicted in Fig. 4) and that according to some examples AMF 630 may further be in direct or indirect communication with an PCF 640.

For example, actions 601 to 606 according to signaling chart 600 may be understood as actions occurring during a registration procedure for UE 610.

In action 601, UE 610 may for example provide a registration message (e.g. a registration request) to AMF 630. For example, UE 610 may provide a registration message in 5G-AN signaling (e.g. RRC) and the 5G-AN may forward the registration message to AMF 630. As an example, a registration request provided in action 601 may comprise a requested NSSA1 and optionally may additionally comprise information indicating a preference of UE 610 of privileging an allowed NSSA1 or a target NSSA1 (e.g. for RRM).

In action 602, AMF 630 may determine (e.g. at least partially based on the registration message obtained in action 601) at least one target NSSA1 as well as an RRM preference information associated with the at least one target NSSA1 and an RFSP associated with the at least one target NSSA1. For example, determining the at least one target NSSA1 comprises interacting of AMF 630 with an NSSF (not shown in Fig. 6).

In some examples, considering that the registration message provided in action 601 additionally comprises information indicating a preference of UE 610 of privileging an allowed NSSA1 or a target NSSA1 (e.g. for RRM), determining the target NSSA1 in action 602 may at least partially based on this preference of UE 160 and a requested NSSA1.

For example, the RRM preference information is indicative of whether to store and use the target NSSA1 and its associated RFSP determined in action 602 by RAN 620 (e.g. one or more RAN nodes of RAN 620) or, instead, to use an allowed NSSA1 and an RFSP associated with the allowed NSSA1 (e.g. after a failure to redirect and/or handover a UE 610 to a cell in a tracking area supporting the target NSSA1). Further, the RRM preference information may for example indicate a time validity of the target NSSA1 and/or the associated RFSP determined in action 602, which time validity may for example indicate after which time period the target NSSA1 is removed from RAN 620 (e.g. from one or more RAN nodes of RAN 620), such that for example RRM may resume to be based on the allowed NSSA1 and an RFSP associated with the allowed NSSA1.

The RRM preference information determined in action 602 may for example further indicate a validity of the target NSSA1 for a tracking area, a network cell or a list of tracking areas. In other examples, the RRM preference information may indicate a priority order of the target NSSA1 and/or one or more alternative target NSSA1.

In some examples, AMF 630 may obtain an RRM preference information and/or an RFSP associated with a target NSSA1 determined in action 602 from PCF 640. For example, AMF 630 may send a request message to PCF 640 in action 603, wherein such a request message may for example indicate the target NSSA1 determined in action 602 and may for example further indicate an RRM preference support indication. In action 604 (e.g. in response to a request according to action 603), PCF 640 may provide an RFSP and/or an RRM preference information associated with the target NSSA1 indicated by the request message according to action 603.

In action 605, RAN 620 (e.g. one or more RAN nodes of RAN 620) receives the target NSSA1 and the RRM preference information associated with the target NSSA1 as well as the RFSP associated with the target NSSA1 as determined in action 602. For example, the RRM preference information associated with the target NSSA1, the target NSSA1 and the RFSP associated with the target NSSA1 may be included in an NG-AP message that for example also carries a registration accept (e.g. a registration accept message), which may for example be provided to UE 610 (e.g. by one or more RAN nodes of RAN 620). In action 606, RAN 620 (e.g. one or more RAN nodes of RAN 620) may then for example operate as instructed according to the preference information associated with the target NSSAI as well as the RFSP associated with the target NSSAI.

Fig. 7 shows another exemplary signaling chart 700 illustrating an exemplary embodiment of the various aspects according to the present disclosure. For exemplary purposes and without limiting the scope of the present disclosure, it is assumed in the following that UE 710 (e.g. a user device as described above) is in direct or indirect communication with a RAN 720 (e.g. one or more RAN network nodes as e.g. depicted in Fig. 5) and an AMF 730 (e.g. an AMF provided by one or more core network nodes as e.g. depicted in Fig. 4) and that according to some example AMF 730 may further be in direct or indirect communication with an PCF 740.

For example, signaling chart 700 (e.g. when compared to signaling chart 600) may be understood to show an alternative where AMF 730 sends to RAN 720 (e.g. one or more RAN nodes of RAN 720) a list of a plurality of target NSSAIs, wherein for example for at least one (e.g. some or each) target NSSAI of the plurality of target NSSAI and respective associated RRM preference information is determined by AMF 730 and sent to RAN 720.

For example, actions 701 to 706 according to signaling chart 700 may be understood as actions occurring during a registration procedure for UE 710.

In action 701, UE 710 may for example provide a registration message (e.g. a registration request) to AMF 730. For example, UE 710 may provide a registration message in 5G-AN signaling (e.g. RRC) and the 5G-AN may forward the registration message to AMF 730. As an example, a registration request provided in action 701 may comprise a requested NSSAI and optionally may additionally comprise information indicating a preference of UE 710 of privileging an allowed NSSAI or a target NSSAI (e.g. for RRM). In action 702, AMF 630 may determine (e.g. at least partially based on the registration message obtained in action 601) a plurality of target NSSAI (e.g. a list including or indicating a plurality of target NSSAI) as well as for example respective RRM preference information associated with the plurality of target NSSAI (e.g. at least one respective RRM preference information associated with each target NSSAI of the plurality of target NSSAIs) and/or a respective RFSP associated with the plurality of target NSSAI (e.g. at least one respective RFSP associated with each target NSSAI of the plurality of target NSSAIs). For example, determining a plurality of target NSSAI comprises interacting of AMF 730 with an NSSF (not shown in Fig. 7).

For example, a respective RRM preference information (e.g. at least one, some, or each) of a plurality RRM preference information determined in action 702 is indicative of whether to store and to use a respective target NSSAI to which the respective RRM preference information is associated and its associated RFSP by RAN 720 (e.g. one or more RAN nodes of RAN 720) or, instead, to use an allowed NSSAI and an RFSP associated with the allowed NSSAI (e.g. after a failure to redirect and/or hand over a UE 710 to a cell in a tracking area supporting the target NSSAI).

Further, a respective RRM preference information may for example indicate a time validity of the target NSSAI to which the respective RRM preference information is associated and the associated RFSP determined in action 702, which time validity may for example indicate after which time period the respective target NSSAI is removed from RAN 720 (e.g. from one or more RAN nodes of RAN 720), such that for example RRM may resume to be based on the allowed NSSAI and an RFSP associated with the allowed NSSAI.

A respective RRM preference information determined in action 702 may for example further indicate a validity of a respective target NSSAI for a tracking area, a network cell or a list of tracking areas. In other examples, a respective RRM preference information may indicate a priority order of a respective target NSSAI and/or one or more alternative target NSSAI. In some examples, AMF 730 may obtain a respective RRM preference information (e.g. at least one, some, or each) of a plurality RRM preference information determined in action 702 and/or an RFSP associated with a target NSSAI to which the respective RRM preference information is associated from PCF 740. For example, AMF 730 may send a request message to PCF 740 in action 703, wherein such a request message may for example indicate the plurality of target NSSAI determined in action 702 and may for example further indicate a respective RRM preference support indication. In action 704 (e.g. in response to a request according to action 703), PCF 740 may provide a respective RFSP and/or a respective RRM preference information associated with the respective target NSSAI indicated by the request message according to action 703.

In action 705, RAN 720 (e.g. one or more RAN nodes of RAN 720) receives the plurality of target NSSAI and the respective RRM preference information associated with the plurality of target NSSAIs as well as the respective RFSP associated with the plurality of target NSSAI as determined in action 702. For example, RAN 720 (e.g. one or more RAN nodes of RAN 720) may receive a list of target NSSAIs as well as respective RRM preference information associated with (e.g. each of) the target NSSAI in the received list. For example, the list of target NSSAIs and/or respective RRM preference information and/or respective RFSP may be included in an NG-AP message that for example also carries a registration accept (e.g. a registration accept message), which may for example be provided to UE 710 (e.g. by one or more RAN nodes of RAN 720).

In action 706, RAN 720 (e.g. one or more RAN nodes of RAN 720) may then for example operate as instructed according to the respective preference information associated with the list of target NSSAI as well as the respective RFSP associated with the list of target NSSAI.

Fig. 8 shows a schematic illustration of examples of tangible and non-transitory computer-readable storage media according to the present disclosure that may for instance be used to implement memory 402 of Fig. 4 or memory 502 of Fig. 5. To this end, Fig. 8 displays a flash memory 800, which may for instance be soldered or bonded to a printed circuit board, a solid-state drive 801 comprising a plurality of memory chips (e.g. Flash memory chips), a magnetic hard drive 802, a Secure Digital (SD) card 803, a Universal Serial Bus (USB) memory stick 804, an optical storage medium 805 (such as for instance a CD-ROM or DVD) and a magnetic storage medium 806.

Any presented connection in the described embodiments is to be understood in a way that the involved components are operationally coupled. Thus, the connections can be direct or indirect with any number or combination of intervening elements, and there may be merely a functional relationship between the components.

Further, as used in this text, the term ‘circuitry’ refers to any of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry)

(b) combinations of circuits and software (and/or firmware), such as: (i) to a combination of processor(s) or (ii) to sections of processor(s)/ software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone, to perform various functions) and

(c) to circuits, such as a microprocessor(s) or a section of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

This definition of ‘circuitry’ applies to all uses of this term in this text, including in any claims. As a further example, as used in this text, the term ‘circuitry’ also covers an implementation of merely a processor (or multiple processors) or section of a processor and its (or their) accompanying software and/or firmware. The term ‘circuitry’ also covers, for example, a baseband integrated circuit or applications processor integrated circuit for a mobile phone.

Any of the processors mentioned in this text, in particular but not limited to processors 401 and 501 of Figs. 4 and 5, could be a processor of any suitable type. Any processor may comprise but is not limited to one or more microprocessors, one or more processor(s) with accompanying digital signal processor(s), one or more processor(s) without accompanying digital signal processor(s), one or more special-purpose computer chips, one or more field-programmable gate arrays (FPGAS), one or more controllers, one or more application-specific integrated circuits (ASICS), or one or more computer(s). The relevant structure /hardware has been programmed in such a way to carry out the described function.

Moreover, any of the actions or steps described or illustrated herein may be implemented using executable instructions in a general-purpose or special-purpose processor and stored on a computer-readable storage medium (e.g., disk, memory, or the like) to be executed by such a processor. References to 'computer-readable storage medium’ should be understood to encompass specialized circuits such as FPGAs, ASICs, signal processing devices, and other devices.

Moreover, any of the actions described or illustrated herein may be implemented using executable instructions in a general-purpose or special-purpose processor and stored on a computer-readable storage medium (e.g., disk, memory, or the like) to be executed by such a processor. References to 'computer-readable storage medium’ should be understood to encompass specialized circuits such as FPGAs, ASICs, signal processing devices, and other devices.

The wording “A, or B, or C, or a combination thereof” or “at least one of A, B and C” or “at least one of A, B or C” may be understood to be not exhaustive and to include at least the following: (i) A, or (ii) B, or (hi) C, or (iv) A and B, or (v) A and C, or (vi) B and C, or (vii) A and B and C. Further, the wording “A and/or B” may be understood to have the same meaning as the wording “at least one of A and B”.

It will be understood that the embodiments disclosed herein are only exemplary, and that any feature presented for a particular exemplary embodiment may be used with any aspect of the present disclosure on its own or in combination with any feature presented for the same or another particular exemplary embodiment and/or in combination with any other feature not mentioned. It will further be understood that any feature presented for an example embodiment in a particular category may also be used in a corresponding manner in an example embodiment of any other category.

LIST OF ABBREVIATIONS

RAN Radio access network gNB Next generation Node B

NR New radio

TA Tracking area

RA Registration area

RFSP Radio access technology frequency selection priority

AMF Access and mobility function

PCF Policy control function

RRC Radio resource control

5G-AN 5G access network

RRM Radio resource management

NSSF Network slice selection function

N G-AP N ext generation application protocol

3GPP 3rd Generation Partnership Project

TS Technical specification

AS Access stratum

NAS Non access stratum

BTS Base transceiver station

NSSA1 Network slice selection assistance information

S-NSSA1 Single network slice selection assistance information

CN Core network

UE User equipment

Claims

1. A method comprising: obtaining, by a first network node, at least one requested network slice selection assistance information, NSSA1; and providing, by the first network node, a first message, at least partially based on the obtained requested NSSA1, wherein the first message comprises a radio resource management, RRM, preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSA1 and/or a radio access technology frequency selection priority, RFSP, associated with the at least one target NSSA1 in a second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node.

2. The method according to claim 1, wherein the RRM preference information further indicates at least one of: whether to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 or, instead, at least one allowed NSSA1 and/or an RFSP associated with the at least one allowed NSSA1 after a failure to redirect and/or hand over a user device to a cell in a tracking area, TA, supporting the target NSSA1; a time validity of the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1; a validity of the at least one target NSSA1 for a TA, a network cell and/or a list of TAs; a priority order of the at least one target NSSA1; or one or more alternative target NSSA1.

3. The method according to claim 1 or 2, wherein the method further comprises: transmitting, by the first network node, the first message to the second network node.

4. The method according to any one of claims 1 to 3, wherein the first message further comprises at least one of: the at least one target NSSA1; the at least one allowed NSSA1; or the RFSP associated with the at least one target NSSA1.

5. The method according to any one of claims 1 to 4, wherein the method further comprises: triggering, by the first network node, a request or update to a third network node, wherein the request or update indicates RRM preference support.

6. The method according to claim 5, wherein the method further comprises: receiving a second message from the third network node, wherein the second message comprises the RRM preference information.

7. A method comprising: obtaining, by a second network node, a first message, wherein the first message comprises an RRM preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSA1 and/or an RFSP associated with the at least one target NSSA1 in the second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node.

8. The method according to claim 7, wherein the first message further comprises at least one of: the at least one target NSSA1; at least one allowed NSSA1; or the RFSP associated with the at least one target NSSA1.

9. The method according to claim 7 or 8, wherein the RRM preference information further indicates at least one of: whether to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI or, instead, at least one allowed NSSAI and/or an RFSP associated with the at least one allowed NSSAI after a failure to redirect and/or hand over a user device to a cell in a TA supporting the target NSSAI; a time validity of the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI; a validity of the at least one target N SSA1 for a TA, a network cell or a list of TAs; a priority order of the at least one target NSSAI; or one or more alternative target NSSAI. A first network node comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the first network node at least to perform: obtaining at least one requested NSSAI; and providing a first message, at least partially based on the obtained requested NSSAI, wherein the first message comprises a radio resource management, RRM, preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSAI and/or an RFSP associated with the at least one target NSSAI in a second network node to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI to drive a radio resource management in the second network node. The first network node according to claim 10, wherein the RRM preference information further indicates at least one of: whether to use the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI or, instead, at least one allowed NSSAI and/or an RFSP associated with the at least one allowed NSSAI after a failure to redirect and/or hand over a user device to a cell in a TA supporting the target NSSAI; a time validity of the at least one target NSSAI and/or the RFSP associated with the at least one target NSSAI; a validity of the at least one target NSSA1 for a TA, a network cell and/or a list of TAs; a priority order of the at least one target NSSA1; or one or more alternative target NSSA1. The first network node according to claim 10 or 11, wherein the at least one memory and the computer program code is configured to, with the at least one processor, cause the first network node at least to further perform: transmitting the first message to the second network node. The first network node according to any one of claims 10 to 12, wherein the first message further comprises at least one of: the at least one target NSSA1; the at least one allowed NSSA1; or the RFSP associated with the at least one target NSSA1. The first network node according to any one of claims 10 to 13, wherein the at least one memory and the computer program code is configured to, with the at least one processor, cause the first network node at least to further perform: triggering a request or update to a third network node, wherein the request or update indicates RRM preference support. The first network node according to claim 14, wherein the at least one memory and the computer program code is configured to, with the at least one processor, cause the first network node at least to further perform: receiving a second message from the third network node, wherein the second message comprises the RRM preference information. A second network node comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the second network node at least to perform: obtaining a first message, wherein the first message comprises an RRM preference information, wherein the RRM preference information is indicative of whether to store at least one target NSSA1 and/or an RFSP associated with the at least one target NSSA1 in the second network node to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 to drive a radio resource management in the second network node. The second network node according to claim 16, wherein the first message further comprises at least one of: the at least one target NSSA1; at least one allowed NSSA1; or the RFSP associated with the at least one target NSSA1. The second network node according to claim 16 or 17, wherein the RRM preference information further indicates at least one of: whether to use the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1 or, instead, at least one allowed NSSA1 and/or an RFSP associated with the at least one allowed NSSA1 after a failure to redirect and/or hand over a user device to a cell in a TA supporting the target NSSA1; a time validity of the at least one target NSSA1 and/or the RFSP associated with the at least one target NSSA1; a validity of the at least one target N SSA1 for a TA, a network cell or a list of TAs; a priority order of the at least one target NSSA1; or one or more alternative target NSSA1. A computer program comprising instructions stored thereon for performing the method according to any one of claims 1 to 6.

20. A computer program comprising instructions stored thereon for performing the method according to any one of claims 7 to 9.