WO2023057980A1

WO2023057980A1 - Network controlled slice prioritization in ue

Info

Publication number: WO2023057980A1
Application number: PCT/IB2022/059618
Authority: WO
Inventors: Ylva Timner; Peter Hedman; Håkan Palm; Ralf Keller; Mikael Wass
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-10-08
Filing date: 2022-10-07
Publication date: 2023-04-13

Abstract

Systems and methods are disclosed herein for controlling prioritization of network slices at the UE based on instructions received from the network. The method comprises receiving by a User Equipment from a network function, instructions of whether and how to apply priority between Network Slices for cell reselection and applying the instruction to prioritize between the Network Slices at cell reselection.

Description

Network Controlled Slice Prioritization in UE

Related Applications

[0001] This application claims the benefit of provisional patent application serial number 63/254002, filed October 8th, 2021, the disclosure of which is hereby incorporated herein by reference in its entirety.

Technical Field

[0002] The present disclosure relates to Network Slice prioritization in the UE for cell reselection.

Background

[0003] The Third Generation Partnership Project (3GPP) Technical Specification (TS) 23.501 V17.2,0 section 5.15 describes Network slices.

[0004] A network slice is a logical network serving a defined business purpose or customer, consisting of all required network resources end-to-end. This means that a network slice consists of all Network Functions and both Control Plane and User Plane required to provide given service(s). Some functions can be shared (i.e., the same Network Function can be in multiple Network Slices), but a network slice consists of all network functions and is not just a subset.

[0005] The current working assumption in 3GPP is that there will be one shared or dedicated Radio Access Network (RAN) infrastructure that will connect to several CN instances (with one or more shared Core network Network Functions (NF), interfacing the RAN, plus additional one or more Core network (CN) NFs which may be dedicated for a slice. Such CN instances are shown in Figure 1 as part of the Central Data Centre (DC). The CN functions can be virtualized deployed on Data centers, cloud, or network function implemented on dedicated hardware.

[0006] In 3GPP rel-17, new solutions are developed to enable slice-aware UE cell reselection in idle and inactive mode. The proposed solutions enable the UE to reselect to a cell on a frequency that support network slices that are in use or intended to be used by the UE. The UE is informed of the slices supported by the cells on frequencies by broadcast signalling (system information). This information can also be signalled in dedicated RRC signalling to each UE.

[0007] One of the solutions under discussion in 3GPP on the rules for slice prioritization is to leave it up to UE implementation. This means each UE vendor can define its own rules. This will lead to different behaviors among UEs, that are likely not in line with the preferences of the network operator. Furthermore, the network (RAN) will not know which slices the UE is prioritizing and hence which cells/frequencies the UE will camp on. This is a problem e.g. for optimized paging algorithms that rely on predicable and known UE behavior. Paging performance might be degraded, e,g. leading to failed connections or the need to page the UE on all frequencies.

Another proposed solution is to use the order of the slices in the Allowed or Configured NSSAI. However, with this solution it is not possible to indicate that several slices have same importance, and neither of these solutions are not taking into account what slices are currently in use. Another problem with using the Allowed NSSAI, is that the UE will never prioritize slices that may not be used in the current cell, e.g slices in the rejected Registration Area (RA). One of the main objectives of slice based cell re-selection is to help the UE find frequency bands where desired slices are served, but with this method that will not be possible if the UE starts at a frequency where a slice is not served.

Summary

[0008] Systems and methods are disclosed herein for the network to control the method the UE is using for prioritizing slices for cell re-selection.

In one example, a method performed in a User equipment (UE) is provided in which the UE comprises the step of receiving from a network function, instructions from a network function (e.g., AMF) where the instruction indicates whether and how to apply priority between Network Slices for cell reselection. The method further comprises the step of applying the instruction to prioritize between Network Slices at cell reselection.

[0009] In one aspect, the instruction comprises one or more priority value to be applied between the network slices at cell reselection.

[0010] In another aspect, the instruction comprises Network Slice Radio Resource Management Groups (NSRRGs) for the network slices [0011] In accordance with one aspect, the instruction is comprised in an information element included in a Non-Access Stratum message, which may be a NAS registration accept message and/or a configuration update message.

[0012] In accordance with another aspect, the method further comprises the step of sending to the network function (AMF) a capability information indicating the UE is capable of receiving the instruction. In another aspect, the instruction is received based on the capability indicating the UE supports receiving the instruction.

[0013] In accordance with another aspect, the instruction further comprises one or more mode of prioritization between the network slices.

[0014] According to another aspect, the UE applying the instruction comprises applying the one or more mode of prioritization between the network slices by prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions and other allowed network slices identified in allowed Network Slice Selection Assistance Information (NSSAI). [0015] Alternatively, the instruction comprises applying the one or more mode of prioritization by prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions, other network slices in allowed NSSAI or network slices the UE intend to provide in requested NSSAI and other network slices in configured NSSAI.

[0016] Alternatively, applying the instruction by prioritizing between network slices is based on implementation specific logic in the UE.

[0017] According to one aspect, a method performed by a Network Function, NF, in a telecommunication network is provided, the method comprising the NF (e.g., AMF in 5G) performs the step of determining whether to provide to a user equipment (UE) instruction indicating whether or how a user equipment (UE) applies priority between network slices for cell reselection and in response to determining that the instruction is to be provided to the UE, sending towards the UE a message comprising the instruction. The message is a NAS message which may be a Registration Accept message or a configuration update message.

[0018] In one aspect, the instruction comprises one or more priority value to be applied by the UE between the network slices at cell reselection which may be included in an information element included in a Non-Access Stratum message. [0019] In one aspect, the AMF receivies from the LIE a capability information indicating the UE is capable of receiving the instruction.

[0020] In accordance with another aspect, the instruction provided to the UE further comprises one or more mode of prioritization between the network slices.

[0021] In one aspect, the one or more mode of prioritization between the network slices comprises prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions and other allowed network slices identified in allowed Network Slice Selection Assistance Information (NSSAI).

[0022] In one aspect, the one or more mode of prioritization between the network slices comprises prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions, other network slices in allowed NSSAI or network slices the UE intend to provide in requested NSSAI and other network slices in configured NSSAI.

[0023] In one aspect, the instruction determined by the network function is based on information obtained from either an operation and management function or a policy function.

Brief Description of the Drawings

[0024] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0025] Figure 1 illustrates a network slice concept;

[0026] Figure 2 illustrates one example of a cellular communications system in which embodiments of the present disclosure;

[0027] Figure 3 illustrate example embodiments in which the cellular communication system of Figure 1 is a Fifth Generation (5G) System (5GS);

[0028] Figures 4 illustrates a procedure in accordance with one embodiment of the present disclosure;

[0029] Figures 5a illustrate a method in the UE in accordance with an embodiment of the present disclosure;

[0030] Figure 5b illustrates a method in a node implementing a Network function (e.g., AMF) in accordance with an embodiment of the present disclosure; [0031] Figures 6, 7, and 8 are schematic block diagrams of example embodiments of a network node; and

[0032] Figures 9 and 10 are schematic block diagrams of example embodiments of a wireless communication device (e.g., a User Equipment device (UE)).

Detailed Description

[0033] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0034] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.

[0035] Radio Node: As used herein, a "radio node" is either a radio access node or a wireless communication device.

[0036] Radio Access Node: As used herein, a "radio access node" or "radio network node" or "radio access network node" is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.

[0037] Core Network Node: As used herein, a "core network node" is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing an Access and Mobility Function (AMF), a User Plane Function (UPF), a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like.

[0038] Communication Device: As used herein, a "communication device" is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehiclemounted mobile device, enabled to communicate voice and/or data via a wireless or wireline connection.

[0039] Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include, but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (loT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless connection.

[0040] Network Node: As used herein, a "network node" is any node that is either part of the RAN or the core network of a cellular communications network/system.

[0041] Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.

[0042] Note that, in the description herein, reference may be made to the term "cell"; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0043] Systems and methods are disclosed herein that address the aforementioned and/or other problems. Embodiments disclosed herein address the aforementioned short comings by providing, to a UE a Network Slice Priority Mode for Cell Reselection (NSPMCR) information, instructing the UE applies priority between Network Slices for cell reselection. This will enable the serving PLMN to control per Access type how the UE may apply priorities between Network Slices for cell reselection purposes.

[0044] In one embodiment, the serving PLMN (AMF or suitable CN function) provides the NSPMCR information to the UE when the UE has indicated that it supports one or both of network slice priority mode for cell reselection and Network Slice Radio Resource Management Group (NSRRG) in for example a registration request towards the network/serving PLMN (i.e., AMF).

[0045] While not being limited to or by any particular advantage. Embodiments of the systems and method disclosed herein may provide a number of advantages over the existing solutions. Embodiments of the present disclosure provide a solution that enables the operator to select the UE behavior that works best for the network.

Different modes could be specified as the needs for more advanced UE behaviors are required. The embodiments described herein propose a framework in which the network provides to the UE instruction (prioritization instruction) on how to prioritize between network slices for cell reselection, the instruction may include signalling different modes of prioritization where the modes can describe which network slices to prioritize for cell reselection compared to other network slices. If the network does not include any prioritization instruction, then the UE determines by itself how to apply priority between the network slices. In other words, the network implicitly or explicitly instructs the UE to apply its own prioritization mechanism. Without the proposed solution, only UE vendor-specific rules for prioritizing slices for cell re-selection will be possible with no control from the network.

[0046] In this description, the terms instruction and prioritization instruction, as provided by the network to the UE and optionally the NG-RAN, are interchangeable. [0047] Figure 2 illustrates one example of a cellular communications system 100 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 100 is for a roaming scenario in which there is a VPLMN 102 and a HPLMN 104. In one embodiment, the cellular communications system 100 is a 5G system (5GS); however, the present disclosure is not limited thereto. In this example, the VPLMN 102 includes a Radio Access Network (RAN) include a RAN node 106 (e.g., a base station), which in the 5GS is a gNB, controlling a corresponding cell 108. The VPLMN 102 also includes a core network 110-v, which in the 5GS is the 5GC. The core network QllO-v includes a number of core network nodes, which in this example are NFs 112-v. Note that the core network 110-v is also referred to herein as a "visited core network 110-v" to distinguish it from a core network 110-h of the HPLMN 104. Likewise, the NFs 112-v are also referred to herein as "visited NFs 112-v" or "vNFs 112-v" to distinguish them from NFs 112-h of the HPLMN 104. The RAN node 106 is connected to the visited core network 110-v.

[0048] The HPLMN 104 also includes the core network 110-h, which includes the NFs 112-h. Note that the core network 110-h of the HPLMN 104 is also referred to herein as a "home core network 110-h" to distinguish it from the visited core network 110-v of the VPLMN 102. Likewise, the NFs 112-h are also referred to herein as "home NFs 112- h" or "hNFs 112-h" to distinguish them from the vNFs 112-v of the VPLMN 102.

[0049] In the embodiments described herein, a wireless communication device 114 is in a roaming scenario in which the HPLMN 104 is the home network of the wireless communication device 114 but the wireless communication device 114 registers to the VPLMN 102. Note that while only one VPLMN 102 is illustrated in Figure 1, as described herein, the wireless communication device 114 may be registered with two (or more) VPLMNs 102 at the same time. In the following description, the wireless communication device 114 is oftentimes a UE and as such sometimes referred to herein as a UE 114, but the present disclosure is not limited thereto.

[0050] Figure 3 illustrates a wireless communication system represented as an example 5G network roaming architecture composed of core Network Functions (NFs), where interaction between any two NFs is represented by a point-to-point reference point/interface. Figure 3 can be viewed as one particular implementation of the system 100 of Figure 2. The details of the various nodes illustrated in Figure 3 are known to those skilled in the art. The interested reader is directed to 3GPP 23.501 V17.2.0.

[0051] Figure 4 illustrates an embodiment for a registration procedure where the network provides an instruction such as an information element (IE) referred to herein as the 'Network Slice Priority Mode for Cell Reselection' (NSPMCR) IE by which the network will inform the UE how to derive the rules for slice prioritization or prioritize between network slices for cell reselection. The mode to use by the UE is signaled over NAS at first registration. More specifically, the mode describes a prioritization scheme between different network slices for cell reselection. As previously indicated, the same instruction may be provided during a configuration update procedure initiated either by the UE or the network.

[0052] Step 1. The NG-RAN 116 and the AMF 300 exchange the support of S-NSSAIs as per current 3GPP specification, TS 38.413;

[0053] Step 2. The UE 114 performs network selection as per current means, i.e., as described in 3GPP TS 23.501 and TS 23.502 (as UE is initially not configured with any slicing information).

[0054] Step 3. The UE 114 sends a Registration Request where it may indicate that it supports NSRRG functionality. Alternatively, the UE 114 may indicate it supports receiving from the AMF 300 an instruction describing how the UE should prioritize between network slices for cell reselection. The Registration may not include any Requested NSSAI as the UE 114 has no slicing configuration for the PLMN.

[0055] Step 4. The NG-RAN 116 forwards the NAS message to the selected AMF 300. [0056] Step 5. The AMF 300 and if supported, the NSSF 130 performs Network Slice selection. The AMF 300 sends the Nssf_NSSelection request to the NSSF. Optionally the request indicates that NSRRG is supported i.e., both the LIE 114 and the AMF 300 supports NSRRG (the information can be provided as a parameter in the Nssf_NSSelection service operation message payload or using the feature negotiation mechanism specified in clause 6.6 of 3GPP TS 29.500);

[0057] Step 6. The NSSF 130 response includes Allowed NSSAI and Configured NSSAI as per current specifications, but, may also include one or more NSRRG for S- NSSAI as per the configuration of the S-NSSAIs in the NSSF 130 (derived at O&M phase and per SLA in case of roaming) i.e., for the S-NSSAI that are configured with any NSRRG. If the AMF did not indicate support for NSRRG, then NSSF 130 may omit providing S-NSSAIs associated with NSRRG.

NOTE: The NSRRG values per S-NSSAI can be provided as part of Configured NSSAI or as separate information.

[0058] Step 7. The AMF 300 determines for the UE a prioritization instruction to instruct the UE for how to prioritize between the network slices for cell reselection. The prioritization instruction is included as an information element (IE) which referred herein as Network Slice Priority Mode for Cell Reselection (NSPMCR). The prioritization instruction is determined based on O&M interaction or by interacting with the PCF (not shown in Figure 4). Alternatively, the AMF 300 may determine the prioritization instruction for the UE by itself.

[0059] Step 8. The AMF 300 sends the Registration Accept to the UE 114 via NG-RAN 116 as per current 3GPP standard procedures where it includes the instruction for how to prioritize between the network slices (hence, prioritization instruction). As previously stated, the prioritization instruction may be included as an information element (IE) which we call herein as Network Slice Priority Mode for Cell Reselection (NSPMCR). The Registration Accept message may include the list of NSRRG for S-NSSAI (in the example, only the S-NSSAI-2 of the Configured NSSAI of the serving network e.g. PLMN is associated to NSRRG-B). The N2/NGAP message carrying the NAS message (8a) (carrying the instruction) also includes the prioritization instruction, (e.g., NSPMCR) for use by the NG-RAN as assistance for optimal handling of RRC Inactive functionality. The UE and the NG-RAN store the received prioritization instruction.

[0060] Step 9. The UE 114 uses the received instruction e.g., NSPMCR and optionally NSSRG during cell reselection and the NG-RAN may use the instruction e.g., NSPMCR received in the N2 message as input to RRC inactive functionality e.g. assigning appropriate RNA etc.

[0061] Step 10. At a later point, the AMF 300 performs the Network Triggered Service Request procedure as per TS 23.502 clause 4.2.3.3. The AMF includes a list of NSRRG for the S-NSSAI(s) related to the service(s) the UE Network Triggered Service Request procedure is for. The AMF 300 includes the NSRRG only for UE's that support NSRRG (i.e., the AMF stored the information that the UE supports NSRRG in the UE context information in the AMF, see clause 5.2.2.2.2 of TS 23.502) or that have indicated support of obtaining prioritization instruction between network slices for cell reselection.

The NG-RAN 116 uses the list of NSRRG (or S-NSSAI) in the paging logic e.g. priorities cells.

[0062] Furthermore, the instruction (aka. prioritization instruction) which may be signalled as an information element, e.g., NSPMCR may encode separate modes of prioritization between network slices (A, B, C, ...), such as for e.g.

A The UE shall prioritize between Network Slices in the following priority order:

1. Network Slices that have PDU Sessions with Active UP

2. Network Slices that have established PDU Sessions

3. Other Network Slices in Allowed NSSAI

B The UE shall prioritize between Network Slices in the following priority order:

1. Network Slices that have PDU Sessions with Active UP

2. Network Slices that have established PDU Sessions

3. Other Network Slices in Allowed NSSAI or Network Slices the UE intend to provide in a Requested NSSAI

4. Other Network Slices in Configured NSSAI

C The UE may prioritize between Network Slices based on implementation specific logic.

D The UE shall prioritize between Network Slices in the following priority order:

1. Network Slices that have PDU Sessions with Active UP

2. Network Slices that have established PDU Sessions

3. Other Network Slices in Allowed NSSAI

For mode D, the UE is further allowed to make additional prioritization, for example if there are slices that the UE intend to provide in a Requested NSSAI, currently not in the Allowed NSSAI, the UE may prioritize them based on implementation specific logic, but the UE shall then request these slices as soon as possible/when registering in a new Registration Area (RA). Note that this might cause service interruption of ongoing PDU sessions. The UE may prioritize the slices not yet in Allowed NSSAI over the Slices already in Allowed NSSAI e.g. if the UE is currently using a UE Route Selection Policy URSP rule not with the highest prioritized precedence order.

Other type of encoding of the modes can be used.

[0063] Alternatively, the instruction may be encoded as a representation of selection logic and the associated priority to be applied e.g. as depicted by the following table (values are examples):

Table 1

[0064] An encoding of the above table, i.e., including assigned priority per selection logic, can be provided with the instruction.

The priority could also be defined as a regular expression of several selection logics sl...s8, signaled to the UE. E.g, using the selection logics of the table above: instruction indicating 6&7; 1&7; 1&6; would translate to the rules: Slices with Active applications and pending user data have highest priority, Slices with Active applications and active UP have second priority, and slices with Active applications but S-NSSAI rejected for RA have third priority.

If the UE is allowed to make its own decision on how to prioritize, the UE may be required to provide how the UE prioritizes by UE providing an encoding of the logic to the network (NG-RAN or 5GC).

[0065] Figure 5a illustrates embodiments of a method in the UE 114 of deriving the rules for slice prioritization for cell reselection. The method comprises step 500a of receiving from a network function (AMF 300), an instruction whether and how to apply priority between Network Slices for cell reselection and in response to receiving the instruction the UE executes the step 505a of applying the instruction to prioritize between Network Slices at cell reselection.

[0066] The UE may receive the instruction in a Non-Access Stratum (NAS) message. The instruction may be encoded in an information element referred to herein as Network Slice Priority Mode for Cell Reselection (NSPMCR) information element. The NAS message is either a registration accept message or a configuration update message, the latter is received at the UE during a UE or a network initiated configuration update procedure.

[0067] In another aspect, the UE may indicate the capability of supporting receiving of the instruction from the network. The capability indicates the UE supporting the instruction/information element for how prioritization of network slices should be applied. The UE can also indicate that it supports network slice radio resource management group indicator. When the UE indicates support of receiving the instruction, it may indicate it as a feature capability or it can indicate the supported modes of prioritization to the network function (AMF) (as explained below). If the UE is allowed to make its own decision on how to prioritize, the UE may be required to provide how the UE prioritizes by providing an encoding of the logic to the network (NG- RAN or 5GC/AMF), for e.g., the UE could indicate the mode or the modes of prioritization between network slices, or other indication of the logic it uses in prioritizing between the network slices.

[0068] The instruction received from the AMF by UE may further indicate one or more different modes (e.g., A, B, C ...) or (1, 2, 3 ...) or any other appropriate identification of the mode or modes could be used. Each mode indicates a rule on how the UE should prioritize between network slices for cell reselection. For example, one mode (e.g., mode A) could indicate to the UE that it should prioritize between

1. network slices that have packet data unit sessions with active User plane,

2. network slices that have established PDU sessions and

3. other network slices identified in allowed Network Slice Selection Assistance Information (NSSAI) in the provided order. Another mode may indicate a different order to execute. [0069] Another mode (e.g., mode B) could indicate that the UE should prioritize between

1. network slices that have packet data unit sessions with active User plane,

2. network slices that have established PDU sessions, other network slices in allowed NSSAI or network slices the UE intend to provide in requested NSSAI and

3. other network slices in configured NSSAI.

[0070] Another mode (e.g., mode C) could indicate that the UE should prioritize between network slices based on implementation specific logic.

[0071] Another mode (e.g., mode D) could indicate the UE shall prioritize between Network Slices in the following priority order:

1. Network Slices that have PDU Sessions with Active UP

2. Network Slices that have established PDU Sessions

3. Other Network Slices in Allowed NSSAI

The above steps 1 , 2, 3 are similar to mode A except that for mode D, the UE is further allowed to make additional prioritization. For example, if there are slices that the UE intend to provide in a Requested NSSAI currently not in the Allowed NSSAI, the UE may prioritize them based on implementation specific logic but the UE shall then request these slices as soon as possible/when registering in a new Registration Area (RA). Note that this might cause service interruption of ongoing PDU sessions.

The UE may prioritize the slices not yet in Allowed NSSAI over the Slices already in Allowed NSSAI e.g., if the UE is currently using a UE Route Selection Policy URSP rule that does not have the highest prioritized precedence order. [0072] It will be apparent that other modes could be specified and signalled to the UE using the same framework.

[0073] Alternatively, the instruction may be encoded as a representation of selection logic and the associated priority to be applied as show in table 1 above.

[0074] The UE may also receive from the network function a list of NSRRG per Serving-NSSAI. The UE supporting NSRRG may use the assigned NSRRG(s) and network slice priorities as per the instruction to prioritize between network slices for cell reselection.

[0075] Figure 5b illustrates embodiments of a method in the network function (e.g., AMF 300) of providing the rules for slice prioritization for cell reselection. The method comprises the step 500b of determining whether to provide to a user equipment (UE) an instruction indicating whether or how a user equipment (UE) applies priority between network slices for cell reselection and step 505b where in response to determining that the instruction is to be provided to the UE, the AMF sends towards the wireless communication device, a message comprising the instruction.

[0076] The instruction may consist of an information element eg., a Network Slice Priority Mode for Cell Reselection (NSPMCR) information element (IE) or any other appropriately named IE indicating a priority between the network slices. The IE is included in a Non-Access Stratum message which may be a NAS registration accept message or a NAS message provided to the UE as part of a NAS configuration update procedure. The instruction may include NSRRGs for NSSAIs.

[0077] The AMF may send the IE to the UE in response to receiving a capability information from the UE indicating the UE supports receiving the instruction, the IE containing information on how to prioritize the network slices.

The capability information received from the UE may further comprise a network slice radio resource management group (NSRRG) indicator indicating the UE supports for NSRRG, i.e., that it supports receiving prioritization instruction to prioritize between network slices.

The AMF may determine that sending the instruction/IE is based on receiving the capability information from the UE and/or the AMF supporting the NSRRG capability. The AMF may determine the instruction based on information obtained from operation and management function or policy function. [0078] As indicated above, the AMF may provide to the LIE as part of the prioritization instruction NSRRG values for some S-NSSAIs, which may be S-NSSAIs in the Configured NSSAI. The NSRRGs are applicable when the PLMN providing the NSSRGs is the registered PLMN. The prioritization instruction and the NSRRGs are valid until updated by an AMF in a subsequent Registration Accept or LIE Configuration Update Command message.

[0079] In one embodiment, the instruction of how to prioritize the network slices provided by the AMF to the UE indicates one or more different modes e.g., (A, B, C ...) or (1, 2, 3 ...) or any other appropriate identification of the modes. Each mode indicates a rule on how the UE should prioritize between the network slices. Alternatively, the instruction may be encoded as a representation of selection logic and the associated priority to be applied as show in table 1 above.

[0080] Other embodiments describing other implementation of the solution are within the scope of this invention, i.e., signalling instruction to the UE on whether to apply priotization (i.e., including a priority between the network slices) and optionally signalling the NSSRGs for the S-NSSAIs that the UE may used when applying the prioritization. For example, the prioritization instruction (i.e., instruction) comprising the modes or the representations of selection logic and the associated priority may be provided to the UE as part of the UE-policy in a UE policy container from the PCF via the AMF.

In this case, the AMF may provide to the PCF any capability information and other information the PCF may require to determine for the UE the instruction for prioritization between network slices (aka, prioritization instruction).

The NG- RAN node may receive from the AMF over the N2/NGAP message the prioritization instruction for the use by the NG-RAN in for example optimal handling of RRC Inactive functionality.

The NG-RAN may also receive the list of NSRRG (or S-NSSAI) over the N2/NG-AP interface to be used in the paging logic e.g., prioritize cells.

[0081] Figure 6 is a schematic block diagram of a network node 600 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node 600 may be, for example, a core network node that implements a NF (e.g., vAMF 300, vNSSF 130, PCF, O&M, or the like) or a network node that implements all or part of the functionality of an NF (e.g., all or part of the functionality of the vAMF 300, vNSSF 130, PCF, O&M, or the like, or the like, as described herein). As illustrated, the network node 600 includes a one or more processors 604 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory 606, and a network interface 608. The one or more processors 604 are also referred to herein as processing circuitry. The one or more processors 604 operate to provide one or more functions of the network node 600 as described herein (e.g., one or more functions of the AMF 300, the NSSF 130 described herein). In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 606 and executed by the one or more processors 604.

[0082] Figure 7 is a schematic block diagram that illustrates a virtualized embodiment of the network node 600 according to some embodiments of the present disclosure. Again, optional features are represented by dashed boxes. As used herein, a "virtualized" network node is an implementation of the network node 600 in which at least a portion of the functionality of the network node 600 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node 600 includes one or more processing nodes 700 coupled to or included as part of a network(s) 702. Each processing node 700 includes one or more processors 704 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 706, and a network interface 708. In this example, functions 710 of the network node 600 described herein (e.g., all or part of the functionality of the vAMF 300, vNSSF 130, PCF, O8iM, or the like, as described herein) are implemented at the one or more processing nodes 700 or distributed across the two or more processing nodes 700 in any desired manner. In some particular embodiments, some or all of the functions 710 of the network node 600 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environ ment(s) hosted by the processing node(s) 700.

[0083] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the network node 600 or a node (e.g., a processing node 700) implementing one or more of the functions 710 of the network node 600 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0084] Figure 8 is a schematic block diagram of the network node 600 according to some other embodiments of the present disclosure. The network node 600 includes one or more modules 800, each of which is implemented in software. The module(s) 800 provide the functionality of the network node 600 described herein. This discussion is equally applicable to the processing node 700 of Figure 7 where the modules 800 may be implemented at one of the processing nodes 700 or distributed across multiple processing nodes 700.

[0085] Figure 9 is a schematic block diagram of a wireless communication device 900 (e.g., wireless communication device or UE 100) according to some embodiments of the present disclosure. As illustrated, the wireless communication device 900 includes one or more processors 902 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 904, and one or more transceivers 906 each including one or more transmitters 908 and one or more receivers 910 coupled to one or more antennas 912. The transceiver(s) 906 includes radio-front end circuitry connected to the antenna(s) 912 that is configured to condition signals communicated between the antenna(s) 912 and the processor(s) 902, as will be appreciated by on of ordinary skill in the art. The processors 902 are also referred to herein as processing circuitry. The transceivers 906 are also referred to herein as radio circuitry. In some embodiments, the functionality of the wireless communication device 900 (e.g., the functionality of the wireless communication device 114 or UE 114 described above) may be fully or partially implemented in software that is, e.g., stored in the memory 904 and executed by the processor(s) 902. Note that the wireless communication device 900 may include additional components not illustrated in Figure 9 such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the wireless communication device 900 and/or allowing output of information from the wireless communication device 900), a power supply (e.g., a battery and associated power circuitry), etc. [0086] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the wireless communication device 900 according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory). [0087] Figure 10 is a schematic block diagram of the wireless communication device 900 according to some other embodiments of the present disclosure. The wireless communication device 900 includes one or more modules 1000, each of which is implemented in software. The module(s) 1000 provide the functionality of the wireless communication device 900 described herein.

[0088] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.

[0089] While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0090] Some example embodiments of the present disclosure are as follows: Embodiment 1. A method performed in a User equipment (UE), the method comprising: o receiving from a network function, instructions whether and how to apply priority between Network Slices for cell reselection; and o applying the instruction to prioritize between Network Slices at cell reselection.

Embodiment 2. The method of embodiment 1 wherein the instruction is a Network Slice Priority Mode for Cell Reselection (NSPMCR) information element included in a Non-Access Stratum message.

Embodiment 3. The method of embodiment 1 or 2 wherein the instruction is received in a NAS registration accept message.

Embodiment 4. The method of embodiment 1 or 2 wherein the instruction is received as part of a NAS configuration update procedure with the network function. .

Embodiment 5. The method of embodiment 1 or 2 wherein the method further comprises the step of sending to the network a capability information indicating the UE is capable of receiving the instruction.

Embodiment 6. The method of embodiment 5 wherein the capability information comprises one or more of an NSPMCR capability indicator and a network slice radio resource management group indicator.

Embodiment 7. The method of embodiment 1 or 2 wherein the instruction/NSPMCR information comprises one or more mode of prioritization between network slices.

Embodiment 8. The method of embodiment 1 or 7 further comprising applying the instruction or the mode by prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions and other network slices identified in allowed Network Slice Selection Assistance Information (NSSAI).

Embodiment 9. The method of embodiment 1 or 7 further comprising applying the instruction by prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions, other network slices in allowed NSSAI or network slices the UE intend to provide in requested NSSAI and other network slices in configured NSSAI.

Embodiment 10. The method of embodiment 1 or 7 further comprising applying the instruction by prioritizing between network slices based on implementation specific logic.

Embodiment 11. The method of embodiment 1 or 6 further comprising receiving from the network function a list of NSRRG per Serving-NSSAI.

Embodiment 12. The method of embodiment 1 or 2 wherein the instruction comprises one or more mode of prioritization.

Embodiment 13. A method performed by a Network Function, NF, in a telecommunication network, the method comprising:

Determining whether to provide to a user equipment (UE) instruction indicating whether or how a user equipment (UE) applies priority between network slices for cell reselection; and

In response to determining that the instruction is to be provided, sending towards the wireless communication device, a message comprising the instruction.

Embodiment 14. The method of embodiment 13 wherein the instruction is a Network Slice Priority Mode for Cell Reselection (NSPMCR) information element (IE) included in a Non-Access Stratum message.

Embodiment 15. The method of any of embodiment 13 or 14 wherein the instruction is included in a NAS registration accept message towards the UE. Embodiment 16. The method of any of embodiment 13 or 14 wherein the instruction is provided to the UE as part of a NAS configuration update procedure.

Embodiment 17. The method of embodiment 13 wherein the method further comprises the step of sending the NSPMCR IE to the UE in response to receiving a capability information from the UE indicating the UE supports NSPMCR.

Embodiment 18. The method of embodiments 17 wherein the capability information further comprises a network slice radio resource management group (NSRRG) indicator.

Embodiment 19. The method of any one of embodiments 13-18 wherein the step of determining is based on one or more of the capability information received from the UE and NSRRG capability of the network function.

Embodiment 20. The method of embodiment 13 wherein the instruction is based on information obtained from operation and management function or policy function.

Embodiment 21. The method of embodiment 13 or 19 further comprising including in the message to the UE a list of NSRRG per Serving-NSSAI.

Embodiment 22. The method of embodiment 13 where in the instruction/NSPMCR IE includes one or more modes of prioritization between network slices or the instruction/NSPMCR IE may be encoded as a representation of selection logic and the associated priority level to be applied (Table 1).

Embodiment 23. A UE adapted to perform the method of any embodiments 1-12.

Embodiment 24. A UE comprising one or more processor and memory comprising instructions which when executed perform the method of any of embodiments 1-12.

Embodiment 25. A network node adapted to perform the method of any of embodiments 11-22. Embodiment 26. A CRM containing instructions, which when executed perform the methods of any of embodiments 11-22.

[0091] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

24 Claims:

1. A method performed in a User equipment (UE), the method comprising:

- receiving from a network function, an instruction indicating whether and how to apply priority between Network Slices for cell reselection; and

- applying the instruction to prioritize between Network Slices at cell reselection.

2. The method of claim 1 wherein the instruction comprises one or more priority value to be applied between the network slices at cell reselection.

3. The method of claim 1 wherein the instruction comprises Network Slice Radio Resource Management Groups (NSRRGs) for the network slices

4. The method of any one of claims 1 to 3 wherein the instruction is comprised in an information element included in a Non-Access Stratum message.

5. The method of any one of claim 1 or 2 wherein the instruction is received in a NAS registration accept message.

6. The method of any one of claim 1 or 2 wherein the instruction is received as part of a NAS configuration update procedure with the network function.

7. The method of any one of claim 1 to 5, wherein the method further comprises the step of sending to the network function a capability information indicating the UE is capable of receiving the instruction.

8. The method of any one of claim 1 to 5 wherein the instruction further comprises one or more mode of prioritization between the network slices.

9. The method of claim 8 wherein applying the instruction comprises applying the one or more mode of prioritization between the network slices by prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions and other allowed network slices identified in allowed Network Slice Selection Assistance Information (NSSAI).

10. The method of claim 8 wherein applying the instruction comprises applying the one or more mode of prioritization by prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions, other network slices in allowed NSSAI or network slices the UE intend to provide in requested NSSAI and other network slices in configured NSSAI.

11. The method of claim 1 further comprising applying the instruction by prioritizing between network slices based on implementation specific logic in the UE.

12. A method performed by a Network Function, NF, in a telecommunication network, the method comprising:

- determining whether to provide to a user equipment (UE) an instruction indicating whether or how a user equipment (UE) applies priority between network slices for cell reselection; and

- in response to determining that the instruction is to be provided, sending towards the UE, a message comprising the instruction.

13. The method of claim 12 wherein the instruction comprises one or more priority value to be applied by the UE between the network slices at cell reselection.

14. The method of claim 12 or 13 wherein the instruction is comprised in an information element included in a Non-Access Stratum message.

15. The method of claim 12 wherein the instruction is included in a NAS registration accept message towards the UE.

16. The method of claim 12 wherein the instruction is provided to the UE as part of a NAS configuration update procedure.

17. The method of any one of claim 12 to 15, wherein the method further comprises the step of receiving from the UE a capability information indicating the UE is capable of receiving the instruction.

18. The method of any one of claim 12 to 15 wherein the instruction further comprises one or more mode of prioritization between the network slices.

19. The method of claim 18 wherein the one or more mode of prioritization between the network slices comprises prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions and other allowed network slices identified in allowed Network Slice Selection Assistance Information (NSSAI).

20. The method of claim 18 wherein the one or more mode of prioritization between the network slices comprises prioritizing between network slices that have packet data unit sessions with active User plane, network slices that have established PDU sessions, other network slices in allowed NSSAI or network slices the UE intend to provide in requested NSSAI and other network slices in configured NSSAI.

21. The method of claim 12 wherein the instruction is based on information obtained from an operation and management function or a policy function.

22. A UE adapted to perform the method of any of claims 1 to 11.

23. A UE comprising one or more processor and memory comprising instructions which when executed perform the method of any of claims 1 to 11.

24. A network node adapted to perform the method of any of claims 12-21.

25. A Computer-Readable Medium containing instructions which when executed by one or more processors of a network node is configures to perform the method of any one of claims 12-21.