Patent Publication Number: US-2023156583-A1

Title: Ran slicing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/989,082, filed on Mar. 13, 2020, entitled “RAN Slicing,” the contents of which are hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     Mobility in RRC_IDLE/RRC_INACTIVE—Cell Selection 
     The principles of PLMN selection in NR are based on the 3GPP PLMN selection principles. Cell selection is required on transition from RM-DEREGISTERED to RM-REGISTERED, from CM-IDLE to CM-CONNECTED and from CM-CONNECTED to CM-IDLE and is based on the following principles:
         The UE NAS layer identifies a selected PLMN and equivalent PLMNs;   Cell selection is always based on Cell Defining SSBs (CD-SSBs) located on the synchronization raster:
           The UE searches the NR frequency bands and for each carrier frequency identifies the strongest cell as per the CD-SSB. It then reads cell system information broadcast to identify its PLMN(s):
               The UE may search each carrier in turn (“initial cell selection”) or make use of stored information to shorten the search (“stored information cell selection”).   
               
           The UE seeks to identify a suitable cell; if it is not able to identify a suitable cell it seeks to identify an acceptable cell. When a suitable cell is found or if only an acceptable cell is found it camps on that cell and commences the cell reselection procedure:
           A suitable cell is one for which the measured cell attributes satisfy the cell selection criteria; the cell PLMN is the selected PLMN, registered or an equivalent PLMN; the cell is not barred or reserved and the cell is not part of a tracking area which is in the list of “forbidden tracking areas for roaming”;   An acceptable cell is one for which the measured cell attributes satisfy the cell selection criteria and the cell is not barred.   
               

     Transition to RRC_IDLE: 
     On transition from RRC_CONNECTED or RRC_INACTIVE to RRC_IDLE, a UE should camp on a cell as result of cell selection according to the frequency assigned by RRC in the state transition message if any. 
     Recovery from Out of Coverage: 
     The UE should attempt to find a suitable cell in the manner described for stored information or initial cell selection herein. If no suitable cell is found on any frequency or RAT, the UE should attempt to find an acceptable cell. 
     In multi-beam operations, the cell quality is derived amongst the beams corresponding to the same cell. 
     Cell Reselection 
     A UE in RRC_IDLE/RRC_INACTIVE performs cell reselection. The principles of the procedure are the following:
         Cell reselection is always based on CD-SSBs located on the synchronization raster.   The UE makes measurements of attributes of the serving and neighbour cells to enable the reselection process:
           For the search and measurement of inter-frequency neighboring cells, only the carrier frequencies need to be indicated.   
           Cell reselection identifies the cell that the UE should camp on. It is based on cell reselection criteria which involves measurements of the serving and neighbour cells:
           Intra-frequency reselection is based on ranking of cells;   Inter-frequency reselection is based on absolute priorities where a UE tries to camp on the highest priority frequency available;   A Neighbor Cell List (NCL) can be provided by the serving cell to handle specific cases for intra- and inter-frequency neighboring cells;   Black lists can be provided to prevent the UE from reselecting to specific intra- and inter-frequency neighboring cells;   Cell reselection can be speed dependent;   Service specific prioritization.   
               

     In multi-beam operations, the cell quality is derived amongst the beams corresponding to the same cell. 
     The cell-ranking criterion Rs for serving cell and Rn for neighboring cells is defined by: 
         Rs=Q meas, s+Q hyst− Q offsettemp
 
         Rn=Q meas, n−Q offset− Q offsettemp
 
     where:
         Qmeas RSRP measurement quantity used in cell reselections.   Qoffset For intra-frequency: Equals to Qoffset s,n , if Qoffset s,n  is valid, otherwise this equals to zero.
           For inter-frequency: Equals to Qoffset s,n  plus Qoffset frequency , if Qoffset s,n  is valid, otherwise this equals to Qoffset frequency .   
           Qoffsettemp Offset temporarily applied to a cell as specified in TS 38.331 [1].       

     The UE may also consider the number of beams above a threshold when performing cell reselection. 
     Cell Categories 
     The cells are categorized according to which services they offer, such as acceptable cell, suitable cell, barred cell, or reserved cell. 
     Acceptable cell: An “acceptable cell” is a cell on which the UE may camp to obtain limited service (originate emergency calls and receive ETWS and CMAS notifications). Such a cell shall fulfil the following requirements, which is the minimum set of requirements to initiate an emergency call and to receive ETWS and CMAS notification in an NR network:
         The cell is not barred, see clause 5.3.1 of TS 38.304 [2] (3GPP TS 38.304, User Equipment (UE) procedures in Idle mode and RRC Inactive state (Release 15), V15.6.0);   The cell selection criteria are fulfilled, see clause 5.2.3.2 of TS 38.304 [ 2 ].       

     Suitable cell: A cell is considered as suitable if the following conditions are fulfilled:
         The cell is part of the selected PLMN or the registered PLMN or PLMN of the Equivalent PLMN list;   The cell selection criteria are fulfilled, see clause 5.2.3.2 of TS 38.304 [2].       

     According to the latest information provided by NAS: 1) The cell is not barred, see clause 5.3.1 of TS 38.304 [2]; 2) The cell is part of at least one TA that is not part of the list of “Forbidden Tracking Areas” (TS 22.261 [3]-3GPP TS 22.261, Service requirements for the 5G system; Stage 1, V16.10.0), which belongs to a PLMN that fulfils the first bullet herein (e.g., cell is part of the selected PLMN or the registered PLMN or PLMN of the Equivalent PLMN list) 
     Barred cell: A cell is barred if it is so indicated in the system information, as specified in TS 38.331 [ 1 ]. 
     Reserved cell: A cell is reserved if it is so indicated in system information, as specified in TS 38.331 [ 1 ]. Following exception to these definitions are applicable for UEs:
         if a UE has an ongoing emergency call, all acceptable cells of that PLMN are treated as suitable for the duration of the emergency call.   camped on a cell that belongs to a registration area that is forbidden for regional provision of service; a cell that belongs to a registration area that is forbidden for regional provision service (TS 23.122 [4], TS 24.501 [5]) is suitable but provides only limited service.       

     Mobility in RRC_IDLE/RRC_INACTIVE—Unified Access Control 
     TS 24.501 [5] (3GPP TS 24.501, Non-Access-Stratum (NAS) protocol for 5G System (5GS); Stage 3, V16.3.0) defines access control techniques for the 5G System. 
     When the 5G NAS layer of a UE detects that it has MO data or signaling to send, the NAS layer needs to perform the mapping of the kind of data or signaling to one or more access identities and one access category and lower layers will perform access barring checks for that request based on the determined access identities and access category. The allowable Access Identity and Access Category Values are defined in TS 22.261 [3]. 
     Access Categories are numbered 0-63. Numbers 32-63 are reserved for operator use. Operators may use NAS singling to configure definitions for each of these categories in the UE. The definitions may be based on what Data Network Name (DNN) the access is associated with, what Single-Network Slice Selection Assistance Information (S-NSSAI) the access is associated with, etc. 
     The NG-RAN may broadcast barring control information associated with Access Categories and Access Identities as specified in TS 38.300 [6] (3GPP TS 38.300, NR; NR and NG-RAN Overall Description; Stage 2 (Release 15), V15.8.0). 
     This background information is provided to reveal information believed by the applicant to be of possible relevance. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art. 
     SUMMARY 
     Disclosed herein are methods, systems, or devices that may assist in performing slice-based cell selection and reselection, offloading of initial access attempts for a given slice to a specific frequency layer, performing slice-aware PLMN selection, performing slice-based barring, performing slice-based Random Access, or performing slice-based paging, among other things. 
     Methods, systems, or devices may perform slice-based cell selection and reselection, where the UE considers the available slices in a cell when deciding which cell to (re-) select. In an example, a mechanism for providing the AS with an NSSAI, that is used to inform the UE of the slice(s) that will be accessed, or are likely to be accessed, when establishing/resuming and RRC connection. In an example, mechanisms to allow a UE to quickly and efficiently determine the slice(s) available in a cell. 
     There are methods for categorizing cells based on the slices available in the cell. There are methods to perform cell selection using slice-based cell selection criteria. There are mechanisms for determining slice-based reselection priorities handling. There are mechanisms to limit cell reselection measurements that is based on which S-NSSAIs are available in the Serving Cell. There are method for excluding a cell for reselection based on S-NSSAI availability. There are methods to determine the reselection priority of a given frequency that is a function of the S-NSSAI availability. There are methods to determine slice-based cell ranking criteria for the serving cell and neighboring cells. There are methods for triggering cell reselection evaluation based on the S-NSSAI based cell selection criteria. There are methods to control the slice-based cell selection and reselection behavior of the UE, which may be used by the network to “steer” the UE towards cells that support specific S-NSSAIs or to “offload” the UE to specific cells or frequency layers when transitioning the UE to RRC_IDLE or RRC_INACTIVE. 
     Methods, systems, or devices may be used to define a Slice Registration Area, that is used to inform a UE of the availability of a network slice within a subset of cells in the PLMN, and methods for the network to determine when the UE moves in/out of an area where a given slice is available. 
     Methods, systems, or devices may perform a slice-aware RRC Connection Establishment/Resume procedure, where a UE that is camped on a cell that does not support the desired slice(s), reselects a cell that does support the desired slice(s) before commencing with the RACH procedure to establish/resume the RRC connection. 
     Methods, systems, or devices may allow offloading of initial access attempts for a given slice to a specific frequency layer, where the cell reselection priority of a given frequency may be determined, at least in part, on the slice for which the RRC connection is being established/resumed. 
     Methods, systems, or devices may perform slice-aware PLMN selection, where information that can be used to determine the slice availability for one or more PLMNs at the UEs current location may be reported to the NAS. 
     There may be a mechanism to control when the UE may search for additional cells on a carrier that is based on the slices supported by the strongest cell(s). 
     Methods, systems, or devices may perform slice-based barring. There are mechanisms to indicate to a UE that a slice is barred. There are mechanisms for handling registration requests for barred slices, where the RAN node informs the AMF of S-NSSAIs that should be rejected. There are mapping rules to determine an access category for an access attempt pertaining to a specific slice. 
     Methods, systems, or devices may improve the efficiency of the existing unified access control mechanism, where the operator-defined access category definitions Information Element that is sent to the UE during registration, or during a configuration update, is updated to include a unique identifier that identifies the set of definitions that are carried in the IE. 
     Methods, systems, or devices may perform slice-based Random Access. There are methods to perform service-based partitioning of RACH resources. There are methods to perform slice-based prioritized Random Access 
     Methods, systems, or devices may perform slice-based Paging. There are slice-based paging mechanisms wherein, the UE behavior in terms of paging monitoring, UE addressing for paging message notification or paging message content is specific to slice or group of slices the UE is interested in. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not constrained to limitations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: 
         FIG.  1    illustrates RRC_IDLE and RRC_INACTIVE Cell Selection and Reselection; 
         FIG.  2    illustrates Network Control of Slice-Based Cell (Re-)Selection Behavior via the RRCRelease Message; 
         FIG.  3    illustrates Slice Availability in UE&#39;s Registration Area; 
         FIG.  4    illustrates Slice Area Registration Update via Registration Request Procedure; 
         FIG.  5    illustrates Slice Area Registration Update via RNA Update Procedure; 
         FIG.  6    illustrates Slice-Aware RRC Connection Establishment Procedure (MO Access); 
         FIG.  7    illustrates Slice-Aware RRC Connection Establishment Procedure (MT Access); 
         FIG.  8    illustrates Procedure for Offloading Initial Access Attempts for a Given Slice to a Specific Frequency Layer; 
         FIG.  9    illustrates UE Learning that a Slice is Barred and the UE takes Action; 
         FIG.  10    illustrates an exemplary RAN Slicing procedure; 
         FIG.  11    illustrates an exemplary RAN slicing procedure; 
         FIG.  12    illustrates an exemplary RAN slicing procedure; 
         FIG.  13    illustrates an exemplary display (e.g., graphical user interface) that may be generated based on the methods, systems, and devices of RAN slicing; 
         FIG.  14 A  illustrates an example communications system; 
         FIG.  14 B  illustrates an exemplary system that includes RANs and core networks; 
         FIG.  14 C  illustrates an exemplary system that includes RANs and core networks; 
         FIG.  14 D  illustrates an exemplary system that includes RANs and core networks; 
         FIG.  14 E  illustrates another example communications system; 
         FIG.  14 F  illustrates a block diagram of an example apparatus or device; and 
         FIG.  14 G  illustrates a block diagram of an exemplary computing system. 
     
    
    
     DETAILED DESCRIPTION 
     Network Slicing 
     TS 38.300 [6] defines the general principles and requirements related to the realization of network slicing in the NG-RAN for NR connected to 5GC and for E-UTRA connected to 5GC are given. 
     A network slice includes a CN part, and one or more of a RAN part, a non-3GPP Access Network part, or a wireline access network part. For example, the RAN part may comprise of one or more RAN capabilities (for example SDAP capability parameters, PDCP capability parameters, RLC capability parameters, MAC capability parameters or Physical layer capability parameters for e.g. supported frequency ranges or frequency bands, frequency band combinations), one or more RAN characteristics (for example supported service type such as eMBB (Slice suitable for the handling of 5G enhanced Mobile Broadband), URLLC (Slice suitable for the handling of ultra-reliable low latency communications), MioT (Slice suitable for the handling of massive IoT), V2X (Slice suitable for the handling of V2X services)), REDCAP (Slice suitable for the handling of Reduced Capability UEs)), one or more RAN functions (e.g., control plane function, or user plane function), and the required resources (e.g., compute, storage and networking resources). Similarly, the CN part may comprise for example of one or more CN capabilities (for e.g. AMF capability parameters, SMF capability parameters or UPF capability parameters), one or more CN characteristics (for example supported service type such as eMBB (Slice suitable for the handling of 5G enhanced Mobile Broadband), URLLC (Slice suitable for the handling of ultra-reliable low latency communications), MioT (Slice suitable for the handling of massive IoT), V2X (Slice suitable for the handling of V2X services)), REDCAP (Slice suitable for the handling of Reduced Capability UEs)), one or more CN functions (e.g., control plane function, or user plane function), and the required resources (e.g., compute, storage and networking resources). The non-3GPP Access Network part or the wireline access network part may comprise of one or more Access Network capabilities (for example MAC capability parameters or Physical layer capability parameters for e.g. supported frequency ranges or frequency bands, frequency band combinations, supported bandwidth or bandwidth combination as applicable), one or more Access Network characteristics (for example supported service type such as eMBB (Slice suitable for the handling of 5G enhanced Mobile Broadband), URLLC (Slice suitable for the handling of ultra-reliable low latency communications), MioT (Slice suitable for the handling of massive IoT), V2X (Slice suitable for the handling of V2X services)), REDCAP (Slice suitable for the handling of Reduced Capability UEs)), one or more Access Network functions (e.g., control plane function, or user plane function), and the required resources (e.g., compute, storage and networking resources). The support of network slicing relies on the principle that traffic for different slices is handled by different PDU sessions. Network can realize the different network slices by scheduling and also by providing different L1/L2 configurations. 
     Each network slice is uniquely identified by a S-NSSAI [7] (3GPP TS 23.501, System Architecture for the 5G System; Stage 2 (Release 16), V16.3.0). Network Slice Selection Assistance Information (NSSAI) includes one or a list of S-NSSAIs where a S-NSSAI is a combination of: mandatory SST (Slice/Service Type) field, which identifies the slice type and includes 8 bits (with range is 0-255); and SD (Slice Differentiator) field, which differentiates among Slices with same SST field and may include 24 bits. 
     The list includes at most 8 S-NSSAI(s). 
     The UE provides NSSAI (Network Slice Selection Assistance Information) for network slice selection in RRCSetupComplete, if it has been provided by NAS. While the network can support large number of slices (hundreds), the UE need not support more than 8 slices simultaneously. 
     Network Slicing is a concept to allow differentiated treatment depending on each customer requirements. With slicing, it is possible for Mobile Network Operators (MNO) to consider customers as belonging to different tenant types with each having different service requirements that govern in terms of what slice types each tenant is eligible to use based on Service Level Agreement (SLA) and subscriptions. 
     The following principles, disclosed in more detail, may be considered for support of Network Slicing in NG-RAN: 1) RAN awareness of slices; 2) Selection of RAN part of the network slice; 3) Resource management between slices; 4) Support of QoS; 5) RAN selection of CN entity; 6) Resource isolation between slices; 7) Access control; 8) Slice availability; 9) Support for UE associating with multiple network slices simultaneously; 10) Granularity of slice awareness; or 11) Validation of UE rights to access a network slice. 
     RAN awareness of slices: NG-RAN supports a differentiated handling of traffic for different network slices which have been pre-configured. How NG-RAN supports the slice enabling in terms of NG-RAN functions (e.g., the set of network functions that comprise each slice) is implementation dependent. 
     Selection of RAN part of the network slice: NG-RAN supports the selection of the RAN part of the network slice, based on the Requested NSSAI provided by the UE or the 5GC which unambiguously identifies one or more of the pre-configured network slices in the PLMN. 
     Resource management between slices: NG-RAN supports policy enforcement between slices as per service level agreements. It should be possible for a single NG-RAN node to support multiple slices. The NG-RAN should be free to apply the best RRM policy for the SLA in place to each supported slice. 
     Support of QoS: NG-RAN supports QoS differentiation within a slice. 
     RAN selection of CN entity: During initial Registration procedure, the UE may provide NSSAI to support the selection of an AMF. If available, NG-RAN uses this information for routing the initial NAS to an AMF. If the NG-RAN is unable to select an AMF using this information or the UE does not provide any such information the NG-RAN sends the NAS signaling to one of the default AMFs. 
     For subsequent accesses, the UE provides a Temp ID, which is assigned to the UE by the 5GC, to enable the NG-RAN to route the NAS message to the appropriate AMF as long as the Temp ID is valid (NG-RAN is aware of and can reach the AMF which is associated with the Temp ID). Otherwise, the methods for initial attach applies. 
     Resource isolation between slices: The NG-RAN supports resource isolation between slices. NG-RAN resource isolation may be achieved by means of RRM policies and protection mechanisms that should avoid the shortage of shared resources if one slice breaks the service level agreement for another slice. It should be possible to fully dedicate NG-RAN resources to a certain slice. How NG-RAN supports resource isolation is implementation dependent. 
     Access control: By means of the unified access control, operator-defined access categories can be used to enable differentiated handling for different slices. NG-RAN may broadcast barring control information (e.g., a list of barring parameters associated with operator-defined access categories) to minimize the impact of congested slices. 
     Slice Availability: Some slices may be available only in part of the network. The NG-RAN supported S-NSSAI(s) is configured by OAM. Awareness in the NG-RAN of the slices supported in the cells of its neighbors may be beneficial for inter-frequency mobility in connected mode. It is assumed that the slice availability does not change within the UE&#39;s registration area. 
     The NG-RAN and the 5GC are responsible to handle a service request for a slice that may or may not be available in a given area. Admission or rejection of access to a slice may depend by factors such as support for the slice, availability of resources, support of the requested service by NG-RAN. 
     Support for UE associating with multiple network slices simultaneously: In case a UE is associated with multiple slices simultaneously, only one signaling connection is maintained and for intra-frequency cell reselection, the UE always tries to camp on the best cell. For inter-frequency cell reselection, dedicated priorities can be used to control the frequency on which the UE camps. 
     Granularity of slice awareness: Slice awareness in NG-RAN is introduced at PDU session level, by indicating the S-NSSAI corresponding to the PDU Session, in signaling including PDU session resource information. 
     Validation of the UE rights to access a network slice: It is the responsibility of the 5GC to validate that the UE has the rights to access a network slice. Prior to receiving the Initial Context Setup Request message, the NG-RAN may be allowed to apply some provisional/local policies, based on awareness of which slice the UE is requesting access to. During the initial context setup, the NG-RAN is informed of the slice for which resources are being requested. 
     Scenario #1: How to (Re-)Select a Cell that Supports the Intended Slice(s) 
     As part of the R17 study on enhancement of RAN slicing, RAN2 has agreed to “Study mechanisms to enable UE fast access to the cell supporting the intended slice.” This includes the study of slice-based cell reselection under network control. Existing mechanisms used to control cell (re-)selection were not designed considering cells may support different slices. This can result in a UE camping on a cell that does not support the intended slice(s). When this happens, the network may have to perform a handover or reject and redirect the UE to a cell that supports the intended slice, which will result in additional signaling and access delays. Mechanisms used to prioritize frequencies can be leveraged to “steer” a UE to cells that support specific slices, but this can be too restrictive since it requires cells in a UE&#39;s registration area on a given frequency to support the same slices. Therefore, to enable fast access to the cell supporting the intended slice, there is a need for a mechanism that allows a UE to consider what slice(s) a cell supports when performing cell (re-)selection, and the 5G system needs to be enhanced to allow the UE to determine that slices are supported by a cell. 
     Furthermore, a UE can be registered to up to 8 slices simultaneously, e.g. can be configured with up to 8 allowed S-NSSAIs. 3GPP is considering relaxing the requirement that the slice availability does not change within the UE&#39;s registration area; therefore, it may be possible that some of the cells in a UEs registration area do not support the slices that are in the UE&#39;s Allowed NSSAI. This can result in the UE camping on a cell that does not support slices that the UE needs to access, even if slice-based cell reselection is used. Therefore, for scenarios where a UE camps on a cell that does not support all of the slices in the UE&#39;s Allowed NSSAI, the 5G system should be enhanced to support the following scenarios. First, the UE may be camped on a cell and should generate MO traffic that is associated with a slice that is not supported in the cell. Second, the network may need to send MT traffic to the UE, but the UE may be camped on a cell that does not support the slice associated with the MT traffic. 
     Scenario #2: Initial Access Imbalance on Different Frequency Layers for Deployments where Slices are Coupled with Carrier/Frequency 
     Operators may couple carrier/frequency with slices, e.g. eMBB slices are supported on 2.6 GHz and 4.9 GHz, while URLLC slices are only supported on 4.9 GHz. To enable fast access to the cells supporting the intended slice(s), the network may be configured to “steer” a UE to camp on a specific frequency layer depending the service required, e.g. a UE requiring eMBB service would be “steered” towards 2.6 GHz cells, and a UE requiring URLLC service would be “steered” towards 4.9 GHz cells. A UE requiring support for multiple services would be “steered” towards a frequency layer supporting the required slices, e.g. a UE requiring eMBB and URLLC services will be “steered” towards 4.9 GHz cells. This is advantageous for scenarios where the UE attempts to resume/establish a URLLC connection, since the UE will camp on a cell that supports URLLC. But for scenarios where an eMBB traffic is being resumed or established, this can result in overloading the 4.9 GHz cells with access attempts or traffic that may be targeted to the 2.6 GHz cells. Therefore, for scenarios where slices are coupled with carrier or frequency, there is a need for a mechanism to balance access attempts across the frequency layers that support the slice(s) for which the access attempt is being made. 
     Scenario #3: Selection of a PLMN that does not Support the Intended Slice(s) at the UEs Location 
     When the UE performs PLMN selection, the PLMN identities of the strongest cell found on each frequency are reported to the NAS. The slices supported by the measured cell are not reported to the NAS, therefore the PLMN selection is not based on the slices supported by the measured cells. This is not problematic for scenarios where all the cells in the network support the same slices. However, for some use cases, it may be useful to only deploy a slice in part of the PLMN. For such deployments, the existing procedure may result in selecting a PLMN that does not support all of the slices in the UE&#39;s Configured NSSAI or the slices that the UE intends to include in the Requested NSSAI of the UEs next Registration Request at the UEs current location. Therefore, there is a need for a slice-aware PLMN selection procedure that considers the slices supported by the measured cells. 
     Scenario #4: Overloading Common Resources Used for Network Access 
     Cells supporting multiple slices may use common resources for network access procedures such as random access and paging. This can result in blocking or delaying access to a given slice due to access attempts made for another slice. To ensure SLAs are met, operators may overprovision their networks with resources used for network access, which is very inefficient. Therefore, there is a need for a mechanism that ensures signaling for access procedures for one slice do not block or delay the execution of access procedures for another slice. 
     Disclosed herein with reference to scenario  1  and other scenarios are methods to perform slice-based cell selection and reselection, where the UE considers the available slices in a cell when deciding which cell to (re-)select. For example, a mechanism for providing the AS with an NSSAI, that is used to inform the UE of the slice(s) that will be accessed, or are likely to be accessed, when establishing/resuming and RRC connection. Mechanisms may allow a UE to quickly and efficiently determine the slice(s) available in a cell. Methods may allow for categorizing cells based on the slices available in the cell. There are methods to perform cell selection using slice-based cell selection criteria. There is a mechanism for determining slice-based reselection priorities handling. There is a mechanism to limit cell reselection measurements that is based on which S-NSSAIs are available in the Serving Cell. There is a method for excluding a cell for reselection based on S-NSSAI availability. Methods can determine the reselection priority of a given frequency that is a function of the S-NSSAI availability. There is a method to determine slice-based cell ranking criteria for the serving cell and neighboring cells. There may be methods for triggering cell reselection evaluation based on the S-NSSAI based cell selection criteria. There are methods to control the slice-based cell selection and reselection behavior of the UE, which may be used by the network to “steer” the UE towards cells that support specific S-NSSAIs or to “offload” the UE to specific cells or frequency layers when transitioning the UE to RRC_IDLE or RRC_INACTIVE. 
     Further disclosed with regard to scenario #1, and other scenarios, is a definition of a Slice Registration Area, that is used to inform a UE of the availability of a network slice within a subset of cells in the PLMN, and methods for the network to determine when the UE moves in/out of an area where a given slice is available. 
     Further disclosed with regard to scenario #1, and other scenarios is a method to perform a slice-aware RRC Connection Establishment/Resume procedure, where a UE that is camped on a cell that does not support the desired slice(s), reselects a cell that does support the desired slice(s) before commencing with the RACH procedure to establish/resume the RRC connection. 
     Disclosed with regard to scenario #2, and other scenarios is a method to allow offloading of initial access attempts for a given slice to a specific frequency layer, where the cell reselection priority of a given frequency may be determined, at least in part, on the slice for which the RRC connection is being established/resumed. 
     Disclosed with regard to scenario #3, and other scenarios, are methods to perform slice-aware PLMN selection, where information that can be used to determine the slice availability for one or more PLMNs at the UEs current location may be reported to the NAS. Further disclosed are mechanisms to control when the UE may search for additional cells on a carrier that is based on the slices supported by the strongest cell(s). 
     Further disclosed herein with regard to scenario #4 and other scenarios are methods to perform slice-based barring, such as: 1) a mechanism to indicate to a UE that a slice is barred; 2) a mechanism for handling registration requests for barred slices, where the RAN node informs the AMF of S-NSSAIs that should be rejected; or 3) mapping rules to determine an access category for an access attempt pertaining to a specific slice. 
     With continued reference to scenario #4, and other scenarios, disclosed herein are methods for improving the efficiency of the existing unified access control mechanism, where the operator-defined access category definitions information element (IE) that is sent to the UE during registration, or during a configuration update, is updated to include a unique identifier that identifies the set of definitions that are carried in the IE. Disclosed herein are methods to perform slice-based Random Access, such as a method to perform service-based partitioning of RACH resources; or methods to perform slice-based prioritized random access. 
     Further, with regard to scenario #4, and other scenarios are methods to perform slice-based Paging, such as a slice-based paging mechanism wherein, the UE behavior in terms of paging monitoring, UE addressing for paging message notification or paging message content is specific to slice or group of slices the UE is interested in. 
     Although some methods are particularly advantageous to implement with regard to a scenario, it is contemplated herein that the methods, steps, or mechanisms, among other things may be used across methods to address one or more scenarios, which may not be specifically provided herein. 
     Mechanisms Associated with Scenario #1 
     Network Slicing allows an operator to provide differentiated treatment depending on each customer&#39;s requirements. MNOs can consider customers as belonging to different tenant types, where service requirements of the tenant govern what network slice types a tenant is eligible to use; this is typically based on SLAs and subscription configuration. A network slice, e.g. an S-NSSAI, may be deployed throughout an entire PLMN or in specific cells within a PLMN. For example, an operator may deploy a network slice in a limited geographic area, e.g. hospital, business park, factory etc., to provide differentiated service for UEs in a specific area. When deployed in specific cells, network slice availability may be defined on a cell, RAN-Based Notification Area (RNA), Tracking Area (TA), or Registration Area (RA) basis. Network slices may also be deployed on specific frequency layers. For example, to co-exist with existing LTE systems, the NR TDD configuration should be aligned with LTE. Therefore, bands where LTE is already deployed, e.g. 2.6 GHz., are more suitable for network slices supporting voice and eMBB services, while bands where LTE is not deployed, e.g. 4.9 GHz, are more suitable for network slices supporting URLLC services with low latency. 
     NAS or AS signaling may be used to inform a UE of the availability of a network slice within a PLMN, e.g. the frequency (or frequencies), cells, RNAs, TAs, or RAs that support a given network slice. For example, Slice Specific Mobility Restrictions provided by the AMF in the NAS Registration and Configuration Update procedures may be used to inform the UE of the availability of a slice in a geographical region or frequency layer. After being informed of the availability of a network slice within a PLMN, the UE may determine whether or not a given cell supports the network slice based on the cell&#39;s Physical Cell ID (PCI); corresponding RNA, TA, or RA; or the frequency layer on which the cell is operating. Awareness of which network slices are available in a given cell may then be used enable slice-based cell selection and reselection in accordance with the subject matter described herein. 
     A cell may also indicate which slices it supports via SI broadcast. For example, the SI broadcast by a cell may include an IE comprised of a list of network slices, e.g. S-NSSAIs, supported by the cell. This IE may be included in an existing SIB or a new SIB may be defined to include the list of network slices supported by the cell. To minimize signaling overhead, the SIB(s) that includes the list of network slices supported by the cell may be configured such that it is only broadcast in response to an on-demand SI request for the corresponding SI message to which the SIB(s) that include the list of network slices supported by the cell are mapped. SI broadcast of slice availability for a given cell may be used on its own or in combination with other the methods described herein to inform a UE of the availability of a network slice within a PLMN. It should be appreciated that instead of broadcasting S-NSSAI values, the SI broadcast might only include partial S-NSSAI values, for example, SST or SD values that are supported in the cell. Alternately, the cell may broadcast S-NSSAI&#39;s, SST&#39;s, or SD&#39;s that are not supported in the cell. 
     And in other alternatives, RACH-based mechanisms may be used, where Msg1, Msg2 or MsgA is used to request information about the slices supported by the cell, and Msg2, Msg4 or MsgB is used to provide the UE with the information about the slices supported by the cell. 
     Slice-Based Cell Selection and Reselection 
     With cell selection, the UE searches for a suitable cell of the selected PLMN, chooses that cell to provide available services, and monitors its control channel. This procedure is defined as “camping on the cell”. With slice-based cell selection, the UE also considers the available slices in a cell, and slice-related information, when deciding which cell to choose to provide available services. 
     The UE shall, if necessary, then register its presence, by means of a NAS registration procedure, in the tracking area of the chosen cell. As an outcome of a successful Location Registration, the selected PLMN then becomes the registered PLMN, as specified in TS 23.122. 
     If the UE finds a more suitable cell, according to the cell reselection criteria, it reselects onto that cell and camps on it. In the case of slice-based cell reselection, the UE also considers the available slices in a cell, and slice-related information, when ranking the cells according the cell reselection criteria. If the new cell does not belong to at least one tracking area to which the UE is registered, location registration is performed. In RRC_INACTIVE state, if the new cell does not belong to the configured RNA, an RNA update procedure is performed. 
     Reasons for camping on a cell in RRC_IDLE state and RRC_INACTIVE state may be fourfold: First, it enables the UE to receive system information from the PLMN. Second, when registered and if the UE wishes to establish an RRC connection or resume a suspended RRC connection, it can do this by initially accessing the network on the control channel of the cell on which it is camped. Slice-based cell (re-)selection ensures the UE camps on a cell supporting the slice(s) it is likely to use when establishing or resuming an RRC connection. Third, if the network needs to send a message or deliver data to the registered UE, it knows (in most cases) the set of tracking areas (in RRC_IDLE state) or RNA (in RRC_INACTIVE state) in which the UE is camped. It can then send a “paging” message for the UE on the control channels of the cells in the corresponding set of areas. The UE will then receive the paging message and can respond. Slice-based cell (re-)selection ensures the UE camps on a cell supporting the slice(s) it is likely to use when responding to a page. Fourth, it enables the UE to receive Earth and Tsunami Warning System (ETWS) and Commercial Mobile Alert System (CMAS) notifications. 
     Table 1 presents the functional division between UE NAS and UE AS in RRC_IDLE and RRC_INACTIVE states. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Functional Division between NAS and AS in 
               
               
                 RRC_IDLE State and RRC_INACTIVE State 
               
            
           
           
               
               
               
            
               
                 Procedure 
                 UE NAS 
                 UE AS 
               
               
                   
               
               
                 Cell Selection 
                 Control cell selection for 
                 Perform measurements 
               
               
                   
                 example by indicating 
                 needed to support cell 
               
               
                   
                 RAT(s) associated with the 
                 selection. 
               
               
                   
                 selected PLMN to be used 
                 Detect and synchronise to a 
               
               
                   
                 initially in the search of a 
                 broadcast channel. Receive 
               
               
                   
                 cell in the cell selection. 
                 and handle broadcast 
               
               
                   
                 Maintain a list of “Forbidden 
                 information. Forward NAS 
               
               
                   
                 Tracking Areas” and provide 
                 system information to NAS. 
               
               
                   
                 the list to AS. 
                 Search for a suitable cell. The 
               
               
                   
                   
                 cells broadcast one or more 
               
               
                   
                   
                 ‘PLMN identity’ in the system 
               
               
                   
                   
                 information. Respond to NAS 
               
               
                   
                   
                 whether such cell is found or 
               
               
                   
                   
                 not. 
               
               
                   
                   
                 If associated RATs is (are) set 
               
               
                   
                   
                 for the PLMN, perform the 
               
               
                   
                   
                 search in this (these) RAT(s) 
               
               
                   
                   
                 and other RATs for that 
               
               
                   
                   
                 PLMN as specified in TS 
               
               
                   
                   
                 23.122. 
               
               
                   
                   
                 If a cell is found which 
               
               
                   
                   
                 satisfies cell selection 
               
               
                   
                   
                 criteria, camp on that cell. 
               
               
                 Cell Reselection 
                 Maintain a list of equivalent 
                 Perform measurements 
               
               
                   
                 PLMN identities and provide 
                 needed to support cell 
               
               
                   
                 the list to AS. 
                 reselection. 
               
               
                   
                 Maintain a list of “Forbidden 
                 Detect and synchronise to a 
               
               
                   
                 Tracking Areas” and provide 
                 broadcast channel. Receive 
               
               
                   
                 the list to AS. 
                 and handle broadcast 
               
               
                   
                 Maintain a CRS-NSSAI and 
                 information. Forward NAS 
               
               
                   
                 provide it to the AS. 
                 system information to NAS. 
               
               
                   
                   
                 Change cell if a more suitable 
               
               
                   
                   
                 cell is found. 
               
               
                   
               
            
           
         
       
     
     CRS-NSSAI 
     To enable slice-based cell (re-)selection, upper layers, e.g. NAS, may provide the AS with an NSSAI, e.g. the Cell (Re-)Selection NSSAI (CRS-NSSAI). The 5-NSSAI(s) in the CRS-NSSAI may correspond to the Requested NSSAI, the Allowed NSSAI or a combination of one or more S-NSSAIs from the Configured NSSAI, or default Configured NSSAI, for the PLMN. 
     The CRS-NSSAI may also be a representation of a NSSAI that the NAS layer wants to request, in other words, the CRS-NSSAI may represent a Requested NSSAI that the NAS layer wants to send. However, the NAS layer may wait to send the Requested NSSAI until the AS, e.g. RRC layer, indicates that a cell has been selected that can provide access to the slices in the CRS-NSSAI. If the RRC Layer indicates that a cell that can provide access to the slices in the CRS-NSSAI cannot be selected, the NAS Layer may provide an updated CRS-NSSAI with less or different S-NSSAI&#39;s. Alternatively, the NAS Layer may order the S-NSSAI&#39;s in the CRS-NSSAI in priority order and, once cell (re-)selection is completed, the RRC layer may provide the NAS layer with an indication of whether the selected cell supports each S-NSSAI in the CRS-NSSAI. The RRC Layer may have considered the priority information when performing cell (re-)selection. 
     An S-NSSAI may only be available part of the PLMN. Therefore, upper layers may provide an indication of the availability of the S-NSSAIs. For example, a field may be included in the CRS-NSSAI to indicate in which Tracking Area(s), RAN Notification Area(s) or cell(s) an S-NSSAI is available. Alternatively, the availability may be indicated in GPS coordinates or any other method used to convey location. The absence of such a field may be used to indicate the S-NSSAI is available throughout the Registration Area or throughout the entire PLMN. 
     An S-NSSAI may only be available on a specific frequency. Therefore, upper layers may provide an indication of the frequency on which an S-NSSAI is available. For example, a field may be included in the CRS-NSSAI to indicate the frequency (or frequencies) on which an S-NSSAI is available. The absence of such a field may be used to indicate the S-NSSAI is available on all frequencies. 
     A cell in a PLMN may only support a subset of the S-NSSAIs in the CRS-NSSAI. Therefore, upper layers may provide the AS with an indication of the priority of an S-NSSAIs to enable ranking of cells based on S-NSSAI availability, e.g. based on which slice are supported by the cell. For example, a field may be included in the CRS-NSSAI to indicate the priority of an S-NSSAI, e.g. High, Medium, Low. Alternatively, the priority of an S-NSSAI may be based on the Slice Service Type (SST), e.g. eMBB, URLLC, MIoT, V2X, where the priority of an SST may be specified per the standards or provided by upper layers. The absence of such a field may be used to indicate the S-NSSAI has a default priority. Alternatively, the field may correspond to flag that is used to indicate S-NSSAI(s) that are preferred or required to be available in a cell. In one example, the preferred or required S-NSSAIs correspond to Subscribed S-NSSAIs marked as a default S-NSSAI in the Subscription Information. 
     A summary of the exemplary fields that may be included in the CRS-NSSAI is shown in Table 2. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Exemplary Fields of a CRS-NSSAI 
               
            
           
           
               
               
               
            
               
                   
                 Field Name 
                 Description 
               
               
                   
                   
               
               
                   
                 S-NSSAI 
                 Identity of the network slice 
               
               
                   
                 Availability 
                 List of TAs, RNAs or PCIs where the S-NSSAI 
               
               
                   
                   
                 is available 
               
               
                   
                 Frequency 
                 Frequencies on which the S-NSSAI is available 
               
               
                   
                 Priority 
                 Priority of the NSSAI 
               
               
                   
                   
               
            
           
         
       
     
     Other fields, corresponding to additional slice-related information may also be included in the CRS-NSSAI, if provided by the network, e.g. slice load, slice resource availability, or other per slice QoS-related metric. 
     In other alternatives, RAN signaling; (e.g., System Information or dedicated signaling, such as an RRCRelease message) may be used to configure or override some or all of the CRS-NSSAI. 
     Cell Categories 
     The cells may be categorized according to which services they offer. For slice-based cell (re-)selection, the UE may also consider the slices available in a cell when categorizing a cell. 
     Whether or not a cell is categorized as an “acceptable cell,” may be based, at least in part, on at least one S-NSSAI available in the cell allowing the UE to obtain limited service. 
     Whether or not a cell is categorized as a “suitable cell” may be based, at least in part, on the cell supporting specific S-NSSAIs in the CRS-NSSAI, e.g. S-NSSAIs marked as “required”, S-NSSAI(s) with the highest priority, S-NSSAI(s) with a priority that is above a threshold, etc. And in another example, a cell may be considered suitable if it supports at least one of the S-NSSAIs in the CRS-NSSAI. 
     For scenarios where slice-based barring is supported, whether or not a cell is categorized as a “barred” cell may be based, at least in part, on the S-NSSAIs in the CRS-NSSAI that are available in the cell being indicated as barred. 
     For scenarios where slice-based reservation is supported, whether or not a cell is categorized as a “reserved” cell may be based, at least in part, on the S-NSSAIs in the CRS-NSSAI that are available in the cell being indicated as reserved. 
     The following are exemplary cell category definitions that consider slice availability, such as acceptable cell, suitable cell, barred cell, or reserved cell, 
     Acceptable cell: An “acceptable cell” is a cell on which the UE may camp to obtain limited service (originate emergency calls and receive ETWS and CMAS notifications). Such a cell shall fulfil the following requirements, which is the minimum set of requirements to initiate an emergency call and to receive ETWS and CMAS notification in an NR network: 
     The cell is not barred;
         At least one S-NSSAI supported in the cell would allow the UE to obtain limited service;   The cell selection criteria are fulfilled.       

     And in other alternatives, the acceptability of a cell may be determined, at least in part, on at least one S-NSSAI being from a subset of S-NSSAI, where the subset may be S-NSSAIs with priority above a certain value, or having some other relevant property of a slice. 
     Suitable cell: A cell is considered as suitable if the following conditions are fulfilled:
         The cell is part of the selected PLMN or the registered PLMN or PLMN of the Equivalent PLMN list;   The cell selection criteria are fulfilled.       

     According to the latest information provided by NAS:
         The cell is not barred;   The cell is part of at least one TA that is not part of the list of “Forbidden Tracking Areas” (TS 22.261 [3]), which belongs to a PLMN that fulfils the first bullet herein (e.g., cell is part of the selected PLMN or the registered PLMN or PLMN of the Equivalent PLMN list);   The cell supports the S-NSSAI(s) marked as “required” in the CRS-NSSAI;   The cell supports at least one S-NSSAI in CRS-NSSAI.       

     And in other alternatives, if a cell is associated with a slice-related metric, the suitability of a cell may be determined, at least in part, on the metric being above a certain value. 
     Barred cell: A cell is barred if it is so indicated in the system information, as specified in TS 38.331 [1] (3GPP TS 38.331, Radio Resource Control (RRC) protocol specification (Release 15), V15.8.0) or if the S-NSSAIs in the CRS-NSSAI that are supported in the cell are indicated as barred. 
     Reserved cell: A cell is reserved if it is so indicated in system information, as specified in TS 38.331 [1] or if the S-NSSAIs in the CRS-NSSAI that are supported in the cell are indicated as reserved. 
     Slice-Based Cell Selection and Reselection Procedure 
     States and State Transitions 
       FIG.  1    shows the states and state transitions and procedures in RRC_IDLE and RRC_INACTIVE. Whenever a new PLMN selection is performed, it causes an exit to number  1 . 
     Cell Selection Process 
     The cell selection process may be performed by one of the following procedures. A first exemplary procedure may be associated with initial cell selection (no prior knowledge of which RF channels are NR frequencies) and provide for: 1) The UE shall scan RF channels in the NR bands according to its capabilities to find a suitable cell; 2) On each frequency, the UE need only search for the strongest cell, except when configured to perform slice-based cell selection, in which case the UE may search for additional cells based on the S-NSSAIs supported by the strongest cell(s); or 3) Once a suitable cell is found, this cell shall be selected. A second exemplary procedure may be associated with cell selection by leveraging stored information: 1) this procedure requires stored information of frequencies and may also information on cell parameters from previously received measurement control information elements or from previously detected cells; 2) Once the UE has found a suitable cell, the UE shall select it; and 3) If no suitable cell is found, the initial cell selection procedure in a) shall be started. 
     It is contemplated herein that priorities between different frequencies or RATs provided to the UE by system information or dedicated signalling may not be used in the cell selection process. However, priorities between different frequencies or RATs that are determined based on the CRS-NSSAI may be used in the cell selection process. 
     Cell Selection Criterion 
     The cell selection criterion S is fulfilled as shown in Table 3, when: 
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
             
            
               
                   Srxlev &gt; 0 AND Squal &gt; 0 
               
               
                 where: 
               
               
                   Srxlev = Q rxlevmeas  − (Q rxlevmin  + Q rxlevminoffset  ) − P compensation  − Qoffset temp   
               
               
                   Squal = Q qualmeas  − (Q qualmin  + Q qualminoffset ) − Qoffset temp   
               
               
                 where: 
               
            
           
           
               
               
            
               
                  Srxlev 
                 Cell selection RX level value (dB) 
               
               
                  Squal 
                 Cell selection quality value (dB) 
               
               
                  Qoffset temp   
                 Offset temporarily applied to a cell as specified in TS 
               
               
                   
                 38.331 [1] (dB) 
               
               
                  Q rxlevmeas   
                 Measured cell RX level value (RSRP) 
               
               
                  Q qualmeas   
                 Measured cell quality value (RSRQ) 
               
               
                  Q rxlevmin   
                 Minimum required RX level in the cell (dBm). If the UE 
               
               
                   
                 supports SUL frequency for this cell, Qrxlevmin is 
               
               
                   
                 obtained from q-RxLevMinSUL, if present, in SIB1, SIB2 
               
               
                   
                 and SIB4, additionally, if Q rxlevminoffsetcellSUL  is present in 
               
               
                   
                 SIB3 and SIB4 for the concerned cell, this cell specific 
               
               
                   
                 offset is added to the corresponding Qrxlevmin to achieve 
               
               
                   
                 the required minimum RX level in the concerned cell; 
               
               
                   
                 else Qrxlevmin is obtained from q-RxLevMin in SIB1, 
               
               
                   
                 SIB2 and SIB4, additionally, if Q rxlevminoffsetcell  is present in 
               
               
                   
                 SIB3 and SIB4 for the concerned cell, this cell specific 
               
               
                   
                 offset is added to the corresponding Qrxlevmin to achieve 
               
               
                   
                 the required minimum RX level in the concerned cell. 
               
               
                  Q qualmin   
                 Minimum required quality level in the cell (dB). 
               
               
                   
                 Additionally, if Q qualminoffsetcell  is signalled for the 
               
               
                   
                 concerned cell, this cell specific offset is added to achieve 
               
               
                   
                 the required minimum quality level in the concerned cell. 
               
               
                  Q rxlevminoffset   
                 Offset to the signalled Q rxlevmin  taken into account in the 
               
               
                   
                 Srxlev evaluation as a result of a periodic search for a 
               
               
                   
                 higher priority PLMN while camped normally in a 
               
               
                   
                 VPLMN, as specified in TS 23.122 [4] (3GPP 23.122, 
               
               
                   
                 Non-Access-Stratum (NAS) functions related to Mobile 
               
               
                   
                 Station (MS) in idle mode (Release 15), V15.7.0.) 
               
               
                  Q qualminoffset   
                 Offset to the signalled Q qualmin  taken into account in the 
               
               
                   
                 Squal evaluation as a result of a periodic search for a 
               
               
                   
                 higher priority PLMN while camped normally in a 
               
               
                   
                 VPLMN, as specified in TS 23.122 [4], 
               
               
                  P compensation   
                 For FR1, if the UE supports the additionalPmax in the 
               
               
                   
                 NR-NS-PmaxList, if present, in SIB1, SIB2 and SIB4: 
               
               
                   
                 max(P EMAX1  −P PowerClass , 0) − (min(P EMAX2 , P PowerClass ) − 
               
               
                   
                 min(P EMAX1 , P PowerClass )) (dB); 
               
               
                   
                 else: 
               
               
                   
                 max(P EMAX1  −P PowerClass , 0) (dB) 
               
               
                   
                 For FR2, P compensation  is set to 0. 
               
               
                  P EMAX1 , P EMAX2   
                 Maximum TX power level of a UE may use when 
               
               
                   
                 transmitting on the uplink in the cell (dBm) defined as 
               
               
                   
                 P EMAX  in TS 38.101 [8] (3GPP TS 38.101, NR; User 
               
               
                   
                 Equipment (UE) radio transmission and reception; Part 1: 
               
               
                   
                 Range 1 Standalone (Release 15), V15.8.2). If UE 
               
               
                   
                 supports SUL frequency for this cell, P EMAX1  and P EMAX2   
               
               
                   
                 are obtained from the p-Max for SUL in SIB1 and NR-NS- 
               
               
                   
                 PmaxList for SUL respectively in SIB1, SIB2 and SIB4 as 
               
               
                   
                 specified in TS 38.331 [1], else P EMAX1  and P EMAX2  are 
               
               
                   
                 obtained from the p-Max and NR-NS-PmaxList 
               
               
                   
                 respectively in SIB1, SIB2 and SIB4 for normal UL as 
               
               
                   
                 specified in TS 38.331 [1]. 
               
               
                  P PowerClass   
                 Maximum RF output power of the UE (dBm) according 
               
               
                   
                 to the UE power class as defined in TS 38.101-1 [8]. 
               
               
                   
               
            
           
         
       
     
     The signaled values Q rxlevminoffset  and Q qualminoffset  are only applied when a cell is evaluated for cell selection as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN (TS 23.122 [4]). During this periodic search for higher priority PLMN, the UE may check the S criteria of a cell using parameter values stored from a different cell of this higher priority PLMN. 
     An additional offset, e.g. Qoffset NSSAI , that is based on which S-NSSAIs in the CRS-NSSAI are supported by a cell may be used when determining the S criteria. This may be referred to as S-NSSAI based cell selection criteria. In a first example, Qoffset S-NSSAI,i  is defined as follows: 
     
       
         
           
             
               Qoffset 
               NSSAI 
             
             = 
             
               
                 ∑ 
                 i 
               
               
                 Qoffset 
                 
                   
                     S 
                     - 
                     NSSAI 
                   
                   , 
                   i 
                 
               
             
           
         
       
     
     where Qoffset S-NSSAI,i  corresponds to an offset that is added based on the availability of the i th  S-NSSAI in the cell. Qoffset S-NSSAI,i  may be configured by higher layers, e.g. as a corresponding field for each S-NSSAI in the CRS-NSSAI. Alternatively, Qoffset S-NSSAI,i  may be determined based on the SDT or SD fields of an S-NSSAI included in the CRS-NSSAI. And in yet another alternative, Qoffset S-NSSAI,i  may correspond to the same value for the slices. Qoffset S-NSSAI,i  may be a positive value when the corresponding slice is available in the cell, thereby making the cell more favorable for cell selection; or a negative value when the corresponding slice isn&#39;t available in the cell. Such an approach allows a UE to be simultaneously steered towards cells that support specific S-NSSAIs and away from cells that don&#39;t support specific S-NSSAIs. Alternatively, a non-zero value may only be used in one of the cases, e.g. when the S-NSSAI is available or absent. Such an approach may allow a UE to be steered towards cells that support specific S-NSSAIs or away from cells that don&#39;t support specific S-NSSAIs. Other alternatives, where the offset may depend on other properties of a slice, e.g. priority of the i th  slice, can also be envisaged. 
     The slice-based Srxlev and Squal values may be defined as follows: 
       Srxlev= Q   rxlevmeas −( Q   rxlevmin   +Q   rxleminoffset )− P   compensation   −Q offset temp +Qoffset NSSAI  
 
       Squal= Q   qualmeas −( Q   qualmin   +Q   qualminoffset )− Q offset temp   +Q offset NSSAI  
 
     Cell Reselection Evaluation Process 
     Reselection Priorities Handling 
     Absolute priorities of different NR frequencies or inter-RAT frequencies may be determined, at least in part, by the S-NSSAIs that are available on that frequency. This may be referred to as S-NSSAI based reselection priorities handling. The priority of an S-NSSAI and the frequency (or frequencies) on which an S-NSSAI is available may be provided in the CRS-NSSAI as described herein. A default priority, e.g. the lowest priority, may be assumed for S-NSSAIs for which a priority is not explicitly provided. And for scenarios where none of the S-NSSAIs are provided with a frequency, the UE may assume S-NSSAI based reselection priority handling is not configured for that frequency. 
     In one example, the priority of a frequency is equal to the priority of the S-NSSAI with the highest priority on that frequency. For scenarios where two frequencies have the same priority, the number of S-NSSAIs configured with that priority may also be considered when determining the priority of a frequency, e.g. a frequency configured with x S-NSSAIs at priority P would be considered a higher priority than a frequency configured with y S-NSSAIs at priority P, assuming x&gt;y. Alternatively, the priority of a frequency may correspond to the average of the priorities of the S-NSSAIs on that frequency. And in another example, the priority of a frequency may correspond to a count of the S-NSSAIs on that frequency, e.g. a frequency where 1 S-NSSAI is configured would have a priority of 1, a frequency where 2 S-NSSAIs are configured would have a priority of 2, etc. 
     In another example, a frequency may be associated with a NSSAI metric, which may be a sum of terms, where each term corresponds to an S-NSSAI. The term may depend on the S-NSSAI priority. For example, the metric is the sum of the priorities of the S-NSSAIs on the frequency. 
     Measurement Rules for Cell-Reselection 
     Rules used by the UE to limit cell reselection measurements may consider which S-NSSAIs are available in the Serving Cell. For example, if the Serving Cell fulfills Srxlev&gt;S IntraSearchP  and Squal &gt;S intraSearchQ ; and the S-NSSAIs in the CRS-NSSAI are available in the Serving Cell, the UE may choose not to perform intra-frequency measurements. Other examples for the aspect of the rule that considers which S-NSSAIs are available in the Serving Cell may be based on one or more of the following: 1) the required S-NSSAIs being available in the Serving Cell; 2) the high priority S-NSSAIs being available in the Serving cell; or 3) the S-NSSAIs with a priority above a threshold being available in the Serving Cell. Other aspects of the rule may be based, at least in part, on an NSSAI-related metric being above a certain value. 
     When to perform inter-frequency and inter-RAT measurements may also be dependent on which S-NSSAIs in the CRS-NSSAI are available in the Serving Cell or on another frequency. For example, if a higher priority S-NSSAI that is not available in the Serving Cell is available on another frequency (or frequencies), the UE shall perform measurements of that frequency (or frequencies). Other examples may be based on one or more of the following: if the required S-NSSAI(s) are not available on the Serving Cell, but are available on a frequency other than the current frequency; or if one or more S-NSSAIs are not available in the Serving Cell, but the S-NSSAIs are available on a frequency other than the current frequency. 
     For scenarios where S-NSSAI based reselection priorities handling as defined herein is used, the reselection priority of a given frequency is a function of the S-NSSAI availability. In this case, rules for determining when to perform inter-frequency and inter-RAT measurements may be based on the reselection priority of a given frequency as follows:
         For a NR inter-frequency or inter-RAT frequency with a reselection priority higher than the reselection priority of the current NR frequency, the UE performs measurements of higher priority NR inter-frequency or inter-RAT frequencies.   For a NR inter-frequency with an equal or lower reselection priority than the reselection priority of the current NR frequency and for inter-RAT frequency with lower reselection priority than the reselection priority of the current NR frequency:
           If the serving cell fulfils Srxlev&gt;S nonIntraSearchP  and Squal &gt;S nonIntraSearchQ , the UE may choose not to perform measurements of NR inter-frequencies or inter-RAT frequency cells of equal or lower priority;   Otherwise, the UE shall perform measurements of NR inter-frequencies or inter-RAT frequency cells of equal or lower priority.
 
Cells with Cell Reservations, Access Restrictions or Unsuitable for Normal Camping
   
               

     For the highest ranked cell (including serving cell) according to cell reselection criteria and for the best cell according to absolute priority reselection criteria, the UE shall check if access is restricted according to the Slice-Based Cell Status and Cell Reservations subject matter described herein. 
     If that cell and other cells have to be excluded from the candidate list, the UE shall not consider these as candidates for cell reselection. This limitation shall be removed when the highest ranked cell changes or the CRS-NSSAI changes. 
     For scenarios where a cell is not suitable due to S-NSSAI availability, the UE may exclude the cell as a candidate for reselection for a duration of time, where the actual duration of time or the maximum duration of time may be specified per the standard or dynamically configured, e.g. up to 300 seconds. For scenarios where the cells on a given frequency layer in the UEs Registration Area are configured with the same S-NSSAI, e.g. are configured to support the same slices, the UE may exclude cells on the same on the same frequency as candidates for cell reselection. Any limitation that is configured may be removed upon a state transition, e.g. if the UE enters into the “Any Cell Selection” state. 
     NR Inter-Frequency and Inter-RAT Cell Reselection Criteria 
     For scenarios where S-NSSAI based reselection priorities handling as defined herein is used, the reselection priority of a given frequency is a function of the S-NSSAI availability or NSSAI related metrics. In this case, cell reselection to a frequency other than the serving frequency can be based on the cell selection Received (RX) signal level, e.g. Srxlev, or the cell selection quality, e.g. Squal. Which quantity is used may be under network control and configured via broadcast or dedicated signaling. NSSAI-based reselection priority handling may use one or more of the following:
         Cell reselection to a higher priority frequency may be based on the Srxlev (or Squal) for a cell of a higher priority frequency exceeding a threshold.   Cell reselection to a cell on an equal priority frequency may be based on the “Intra-frequency and Equal Priority Inter-Frequency Cell Reselection Criteria” subject matter described herein.   Cell reselection to a cell on a lower priority frequency may be based on the Srxlev (or Squal) for the serving cell being below a threshold and Srxlev (or Squal) for a cell of a lower priority frequency exceeding a threshold.       

     Cell reselection to a higher priority frequency shall take precedence over a lower priority frequency if multiple cells of different priorities fulfill the cell reselection criteria. If more than one cell meets the cell reselection criteria, the UE may reselect a cell as follows:
         If the highest-priority frequency is an NR frequency, the highest ranked cell among the cells on the highest priority frequency(ies) meeting the criteria according to “Intra-frequency and Equal Priority Inter-Frequency Cell Reselection Criteria” subject matter described herein.   If the highest-priority frequency is from another RAT, the strongest cell among the cells on the highest priority frequency(ies) meeting the criteria of that RAT.       

     Intra-frequency and Equal Priority Inter-Frequency Cell Reselection Criteria 
     The cell-ranking criterion Rs for serving cell and Rn for neighboring cells is defined by the following as in Table 4: 
     
       
         
           
               
             
               
                 TABLE 4 
               
               
                   
               
             
            
               
                  Rs = Q meas,s  +Q hyst  − Qoffset temp   
               
               
                  Rn = Q meas,n  −Qoffset − Qoffset temp   
               
               
                 where: 
               
            
           
           
               
               
               
            
               
                   
                  Qmeas 
                  RSRP measurement quantity used in cell 
               
               
                   
                   
                   reselections. 
               
               
                   
                 Qoffset 
                 For intra-frequency: Equals to Qoffset s,n , if Qoffset s,n   
               
               
                   
                   
                 is valid, otherwise this equals to zero. 
               
               
                   
                   
                 For inter-frequency: Equals to Qoffset s,n  plus 
               
               
                   
                   
                 Qoffset frequency , if Qoffset s,n  is valid, otherwise this 
               
               
                   
                   
                 equals to Qoffset frequency . 
               
               
                   
                 Qoffset temp   
                 Offset temporarily applied to a cell as specified in 
               
               
                   
                   
                 TS 38.331 [1]. 
               
               
                   
                   
               
            
           
         
       
     
     The UE performs ranking of cells that fulfill the cell selection criterion S. The cells are ranked according to the R criteria by deriving Q meas,n  and Q meas,s  and calculating the R values using the RSRP results. 
     The UE may be configured to perform slice-based cell reselection. When slice-based cell reselection is configured, the UE considers which S-NSSAIs in the CRS-NSSAI are available in the candidate cells. Configuration of the CRS-NSSAI may imply that slice-based cell reselection in configured. Alternatively, slice-based reselection may be configured explicitly by higher layers, e.g. the NAS may set/clear a flag to indicate slice-based reselection is enabled/disabled. 
     When slice-based cell reselection is configured, the UE may perform cell reselection to the cell that supports the highest number of S-NSSAIs from the CRS-NSSAI. In another example, the UE may perform cell reselection to the cell that supports the highest number of required S-NSSAIs from the CRS-NSSAI. And in other examples, the cell reselection decision UE may be based on the priorities of the S-NSSAIs available in a cell, e.g. the UE may perform cell reselection to the cell supporting the highest priority S-NSSAI or the highest number of S-NSSAIs configured with the highest priority if multiple S-NSSAIs are configured with the same priority; or the UE may perform cell reselection to the cell based on a metric that corresponds to the sum or weighted sum of the priorities of the available S-NSSAIs, where the weights may be configurable or based on other slice-related info, e.g. per-slice load/resource availability in a cell, etc. For these examples, if there are multiple such cells, the UE performs cell reselection to the highest ranked cell among them. 
     In another alternative, an offset, e.g. Qoffset NSSAI , that is based on which S-NSSAIs in the CRS-NSSAI are available in the serving and neighboring cells may be used when determining the R criteria. In a first example, Qoffset S-NSSAI,i  is defined as follows: 
     
       
         
           
             
               Qoffset 
               NSSAI 
             
             = 
             
               
                 ∑ 
                 i 
               
               
                 Qoffset 
                 
                   
                     S 
                     - 
                     NSSAI 
                   
                   , 
                   i 
                 
               
             
           
         
       
     
     where Qoffset S-NSSAI,i  corresponds to an offset that is added based on the availability of the i th  S-NSSAI in the cell. Qoffset S-NSSAI,i  may be configured by higher layers, e.g. as a corresponding field for each S-NSSAI in the CRS-NSSAI. Alternatively, Qoffset S-NSSAI,i  may be determined based on the SDT or SD fields of an S-NSSAI included in the CRS-NSSAI. And in yet another alternative, Qoffset S-NSSAI,i  may correspond to the same value for the slices. Qoffset S-NSSAI,i  may be a positive value when the corresponding slice is available in the cell, thereby making the cell more favorable for cell reselection; or a negative value when the corresponding slice isn&#39;t available in the cell. Such an approach allows a UE to be simultaneously steered towards cells that support specific S-NSSAIs and away from cells that don&#39;t support specific S-NSSAIs. Alternatively, a non-zero value may only be used in one of the cases, e.g. when the S-NSSAI is available or absent. Such an approach allows a UE to be steered towards cells that support specific S-NSSAIs or away from cells that don&#39;t support specific S-NSSAIs. Other alternatives, where the offset may depend on other properties of a slice, e.g. priority of the i th  slice, can also be envisaged. 
     The slice-based cell-ranking criterion Rs for serving cell and Rn for neighboring cells may be defined as follows in Table 5: 
     
       
         
           
               
             
               
                 TABLE 5 
               
               
                   
               
             
            
               
                  Rs = Q meas,s  + Q hyst  + Qoffset NSSAI  − Qoffset temp   
               
               
                  Rn = Q meas,n  + Qoffset NSSAI  − Qoffset − Qoffset temp   
               
               
                 where: 
               
            
           
           
               
               
            
               
                   Qmeas 
                 RSRP measurement quantity used in cell 
               
               
                   
                 reselections. 
               
               
                   Qoffset 
                 For intra-frequency: Equals to Qoffset s,n , if 
               
               
                   
                 Qoffset s,n  is valid, otherwise this equals to 
               
               
                   
                 zero. 
               
               
                   
                 For inter-frequency: Equals to Qoffset s,n   
               
               
                   
                 plus Qoffset frequency , if Qoffset s,n  is valid, 
               
               
                   
                 otherwise this equals to Qoffset frequency . 
               
               
                   Qoffset temp   
                 Offset temporarily applied to a cell as 
               
               
                   
                 specified in TS 38.331 [1], 
               
               
                   Qoffset NSSAI   
                 Offset based on which S-NSSAIs in the CRS- 
               
               
                   
                 NSSAI are available in the candidate cells. 
               
               
                   
               
            
           
         
       
     
     Alternatively, Qoffset NSSAI  may be included in one of the other offsets. For RS, Qoffset S-NSSAI  may be added to Qhyst; and for Rn, Qoffset S-NSSAI,i  may be subtracted from Qoffset, assuming a positive values of Qoffset S-NSSAI,i  imply a slice is available and negative values imply a slice is not available. 
     For scenarios where slices are deployed on specific frequency layers, Rn may be defined such that Qoffset NSSAI  is only be applied for inter-frequency cells that support a different set of S-NSSAIs than the serving cell. 
     Mechanisms to avoid ping-ponging between cells may also be defined. For example, the UE may only reselect the new cell if the following conditions are met: 1) The new cell is better than the serving cell according to the cell reselection criteria specified during a time interval Treselection RAT ; or 2) more than 1 second has elapsed since the UE camped on the current serving cell. 
     In the examples herein, if the cell is found to be not-suitable, the cell may be not considered a candidate for cell reselection in accordance with the “Cells with Cell Reservations, Access Restrictions or Unsuitable for Normal Camping” described herein. 
     Cell Reselection Parameters in System Information Broadcasts 
     Slice-based cell reselection parameters may be broadcast in system information or configured via dedicated signaling. Slice-based cell reselection parameters may include, but are not limited to hysteresis values, offsets or thresholds that are used when calculating the S and R criterion while performing slice-based cell (re-)selection. The slice-based cell reselection parameters may be broadcast in addition to the cell-based parameters, in which case, they may be used to override the cell-based values. Alternatively, the slice-based parameters may also include new parameters that are only applicable for slice-based cell reselection. Slice-related info such as load, resource availability, QoS information, etc. may also be broadcast. 
     Camped Normally State 
     The Camped Normally state is applicable for UEs in RRC_IDLE and RRC_INACTIVE. When camped normally, the UE acquires relevant System Information, monitors for Short Messages transmitted with P-RNTI over DCI and monitors for paging. The UE also performs measurements necessary for the cell reselection evaluation procedure. A UE in this state may execute the cell reselection evaluation procedure according to UE internal triggers and when information on the BCCH used for the cell reselection evaluation procedure has been modified. In addition to defining UE internal triggers so as to meet performance as specified in TS 38.133 [9] (3GPP TS 38.133, NR; Requirements for support of radio resource management (Release 15), V15.8.0), UE internal triggers may also be based on the S-NSSAI based cell selection criteria described herein. Reconfiguration/updating of the CRS-NSSAI may also trigger execution of the cell reselection procedure. For example, a change in the set of S-NSSAIs in the CRS-NSSAI may trigger the cell reselection evaluation procedure such that the UE searches for a more suitable cell to camp on. 
     Selection of Cell at Transition to RRC_IDLE or RRC_INACTIVE State 
     The RRCRelease message is used by the network to transition the UE to RRC_IDLE or RRC_INACTIVE. The RRCRelease message may include information that can be used to control the slice-based cell selection and reselection behavior of the UE, which may be used to “steer” the UE towards cells that support specific S-NSSAIs or to “offload” the UE to specific cells or frequency layers. 
     For example, the network may redirect the UE to a specific carrier based on the UE&#39;s NSSAI, e.g. CRS-NSSAI, Allowed NSSAI, Configured NSSAI, etc. 
     In another example, the network may provide the UE with a reselection priority for one or more frequencies, where the priority of a given frequency may be based on the S-NSSAIs available on that frequency and the UE&#39;s NSSAI. The cell reselection priorities provided in the RRCRelease message may be used to override the reselection priorities determined by the UE indefinitely or for a fixed duration, e.g. until timer T320 expiration. 
     In another example, the network may deprioritize a frequency (or frequencies), where the determination of which frequency (or frequencies) to deprioritize may be based on the S-NSSAIs available on a given frequency and the UE&#39;s NSSAI. The deprioritization of a frequency (or frequencies) provided in the RRCRelease message may be used to override the reselection priority determined by the UE for the corresponding frequency (or frequencies) indefinitely or for a fixed duration, e.g. until timer T325 expiration. 
     In another example, the network may use the RRCRelease message to update or override the UE&#39;s Allowed or Configured NSSAI. In one aspect of this example, the RRCRelease message is used to add/remove one or more S-NSSAIs in the CRS-NSSAI. For an S-NSSAI that is being added, the RRCRelease messages may also include additional fields describing the attributes of the S-NSSAI, such as those in Table 2. In another aspect of the example, the RRCRelease message is used to update one or more of the of the attributes associated with an S-NSSAI in the CRS-NSSAI. The information provided in the RRCRelease message may be used to replace some or all of the CRS-NSSAI or to override the existing CRS-NSSAI for a fixed duration of time, e.g. until expiration of a timer whose duration is set to a value signaled in the RRCRelease message. 
     At reception of RRCRelease message to transition the UE to RRC_IDLE or RRC_INACTIVE, the UE shall attempt to camp on a suitable cell according to redirectedCarrierInfo if included in the RRCRelease message. If the UE cannot find a suitable cell, the UE is allowed to camp on any suitable cell of the indicated RAT. If the RRCRelease message does not include the redirectedCarrierInfo, the UE shall attempt to select a suitable cell on an NR carrier. If no suitable cell is found, the UE shall perform cell selection using stored information in order to find a suitable cell to camp on. 
       FIG.  2    is an illustration of how the RRCRelease message may be used to enable network control of the slice-based cell (re-)selection behavior of a UE  201 . In  FIG.  2   . At step  211 , UE  201  receives an RRCRelease message that includes information to steer” the UE  201  towards cells that support specific S-NSSAIs. At step  212 , the UE  201  releases the RRC connection and begins searching for a suitable cell to camp on in accordance with the information provided in the RRCRelease message. At step  213   a -step  213   c , the UE  201  performs measurements of neighbor cells  203 , ranks the cells that fulfill the S criteria, or reads the SI of one or more neighbor cells  203  to determine the suitability of the neighbor cell(s)  203 . At step  214 , UE  201  selects a suitable cell to camp on in accordance with the slice-based cell (re-) selection subject matter described herein. 
     The RRCRelease message may be used to “steer” the UE  201  towards cells that support specific S-NSSAIs or to “offload” the UE  201  to specific cells or frequency layers and may indicate to the UE  201  that the RRCRelease Message was sent because the UE  201  is not permitted to access the resources of a certain slice at the current time. The slice will be identified with an S-NSSAI&#39;s. Reception of this message may cause the UE  201  to select a different cell, handover to a different cell, to terminate any PDU Sessions that are associated with the slice and to de-register from the slice. Deregistration from the slice is achieved by sending a NAS Layer Registration message to the network with a Requested NSSAI that does not include the S-NSSAI of the slice that the UE  201  is de-registering from. 
     Any Cell Selection State 
     The Any Cell Selection state is applicable for UEs in RRC_IDLE and RRC_INACTIVE. When in this state, the UE  201  performs the cell selection process to find a suitable cell to camp on. If the cell selection process fails to find a suitable cell after a complete scan of RATs and frequency bands supported by the UE  201 , the UE  201  may attempt to find an acceptable cell of any PLMN to camp on, trying RATs that are supported by the UE  201  and searching first for a high-quality cell. 
     The CRS-NSSAI may be PLMN specific. When attempting to find an acceptable cell of any PLMN, the CRS-NSSAI may be updated to be based on the Configured NSSAI for the PLMN on which the UE  201  is searching for an acceptable cell. If no Configured NSSAI has been provided for a the PLMN on which the UE  201  is searching for an acceptable cell, the CRS-NSSAI may be updated to be based on a Default Configured NSSAI that applies to any PLMN. 
     Alternatively, the CRS-NSSAI may include a mapping of S-NSSAIs for the HPLMN to S-NSSAIs for the PLMN on which the UE  201  is searching for an acceptable cell. 
     And in another alternative, slice-based cell selection may be disabled when attempting to find an acceptable cell of any PLMN while in this state. 
     Camped on Any Cell State 
     The Camped on Any Cell state is only applicable for UEs in RRC_IDLE. When in this state, the UE  201  acquires relevant System Information, monitors for Short Messages transmitted with P-RNTI over DCI. The UE  201  also performs measurements necessary for the cell reselection evaluation procedure. A UE  201  in this state may execute the cell reselection evaluation procedure according to UE  201  internal triggers and when information on the BCCH used for the cell reselection evaluation procedure has been modified. In addition to defining UE  201  internal triggers so as to meet performance as specified in TS 38.133 [9], UE  201  internal triggers may also be based on the S-NSSAI based cell selection criteria described herein. Reconfiguration/updating of the CRS-NSSAI may also trigger execution of the cell reselection procedure. A UE  201  in this state may also regularly attempt to find a suitable cell trying the frequencies of the RATs that are supported by the UE  201 . If a suitable cell is found, the UE  201  transitions to the Camped Normally state. If the UE  201  supports voice services and the current cell does not support IMS emergency calls as indicated by the field ims-EmergencySupport in SIB1, the UE  201  performs cell selection/reselection to an acceptable cell that supports emergency calls in any supported RAT regardless of priorities provided in system information from current cell, if no suitable cell is found. 
     Slice Registration Area 
     It may be desirable for network operators to configure the network such that certain slices are only available via a subset of the cells in the PLMN. It might not be practical to give the UE  201  a complete list of cells where a given slice is available, therefore, the UE  201  may be informed of the availability of a network slice within in a subset of the cells in the PLMN. The network may determine the subset of cells based on the proximity of the cells to the UEs location. For example, the network may inform the UE  201  of the availability of a network slice for cells that comprise the UEs Registration Area. This may be referred to as the Slice Registration Area for a given network slice. 
     A given network slice may be available in 0 or more cells within the UEs Registration Area.  FIG.  3    is an exemplary network deployment that shows a UE&#39;s Registration Area where a first slice (e.g., S-NSSAI x ), may be available in the cells of the UE&#39;s Registration Area and a second slice, e.g. S-NSSAI y , is available in a subset of the cells in the UE&#39;s Registration Area. In this example, the network slice availability is the same throughout a given TA, therefore the UE  201  may determine if a cell supports a specific network slice based on the Tracking Area Code broadcast in SIB1. The same concepts may also be applied for RNAs if the network slice availability is the same throughout a given RNA, e.g. the UE  201  may determine if a cell supports a specific network slice based on the RAN Area Code broadcast in SIB1. 
     The UE  201  may inform the network when it moves in/out of a Slice Registration Area. In one example, a Mobility Registration Update procedure may be used to inform the network of a change in the Slice Registration Area(s). Information related to the Slice Registration Area(s) in which the UE  201  is located may then be used by the network to determine which PDU sessions can be supported by a UE  201  at a given time. For example, if a UE  201  is registered to an S-NSSAI supporting a specific PDU session or sessions, but the UE  201  is not located in a Slice Registration Area that supports that S-NSSAI, the network may “suspend” the PDU sessions(s) associated with that S-NSSAI. The UE  201  may be informed that the PDU sessions and the UE&#39;s activity in the slice (e.g., S-NSSAI) are suspended in the Registration Response or in a subsequent PDU Session Modification procedure. 
       FIG.  4    is an illustration of such a procedure. In this example, we assume cells  205  in TA 1  support S-NSSAI x  and cells  206  in TA 2  support S-NSSAI x  and S-NSSAI y , as shown in  FIG.  3   . Below are exemplary steps for  FIG.  4   , in which, as with other methods herein, some steps may not need to be executed (e.g., step  239  of  FIG.  4   ). At step  230 , the UE  201  is camped on a cell  206  in TA 2 . At step  231 , the UE  201  reselects a cell  205  in TA 1 . At step  232 , the UE  201  performs a Mobility Registration Update procedure to inform the network that it has moved to a TA that supports a different set of RAN slices, e.g. S-NSSAI y  is not available. At step  233 , the AMF  207  invokes the SMF&#39;s UpdateSMContext service to inform the SMF that the UE  201  is not able to transmit/receive data for PDU sessions associated with slices that are not available, e.g. PDU sessions associated S-NSSAI y . The SMF/UPF  208  may buffer or drop DL data that arrives for PDU sessions associated with S-NSSAI y . At step  234 , the AMF  207  sends a Registration Accept message to the UE  201  and indicates to the UE  201  that PDU Sessions that are associated with the S-NSSAI that is not available are suspended or terminated. The Registration Accept may also include a timer that indicates that the PDU Session should be considered terminated if the UE  201  does not Re-Register with the network in a location where the S-NSSAI is allowed before the timer has expired. 
     With continued reference to  FIG.  4   , at step  235 , the UE  201  reselects a cell  206  in TA 2 . At step  236 , the UE  201  performs a Mobility Registration Update procedure to inform the network that it has moved to a TA that supports a different set of RAN slices, e.g. 5-NSSAI y  is available. At step  237 , the AMF  207  invokes the SMF&#39;s UpdateSMContext service to inform the SMF/UPF  208  that the UE  201  is able to transmit/receive data for PDU sessions associated with slices that are available, e.g. PDU sessions associated S-NSSAI y . At step  238 , the AMF  207  sends a Registration Accept message to the UE  201  and indicates to the UE  201  that PDU Sessions that are associated with the S-NSSAI that are no longer suspended. At step  239 , the UE  201  commences with UL/DL data transmission and reception for PDU sessions associated with S-NSSAI y , where the DL data may include any data that was buffered by the SMF/UPF  208  while the UE  201  was in TA 1 . UL/DL data transmission and reception for PDU sessions associated with other S-NSSAIs supported in TA 2 , e.g. S-NSSAI x , may also occur. 
     In another example, slice availability is defined at the RNA level. An RNA Update procedure, which is used to inform the network of a change in RAN, may also be used to inform the network of a change in Slice Registration Area(s). In this example, we assume cells in RNA 1  support S-NSSAI x  and cells in RNA 2  support S-NSSAI x  and S-NSSAI y .  FIG.  5    is an exemplary illustration of Slice Area Registration Update via RNA Update Procedure. Below are exemplary steps for  FIG.  5   , in which, as with other methods herein, some steps may not need to be executed (e.g., steps  11 - 13  of  FIG.  5   , among others). At step  240 , the UE  201  is camped on a cell  210  in RNA 2 . At step  241 , the UE  201  reselects a cell  209  in RNA 1 . At step  242 , the UE  201  performs an RNA update procedure to inform the network that it has moved to RNA 1 . At step  243 , the RAN node, e.g., gNB in RNA 1 , sends an N2 Message to inform the AMF  207  that the UE  201  has moved to a location that supports a different set of RAN slices, e.g., S-NSSAI y  is not available. At step  244 , the AMF  207  invokes the SMF&#39;s UpdateSMContext service to inform the SMF  208  that the UE  201  is not able to transmit/receive data for PDU sessions associated with slices that are not available, e.g., PDU sessions associated S-NSSAI y . The SMF/UPF  208  may buffer or drop DL data that arrives for PDU sessions associated with S-NSSAI y . 
     With continued reference to  FIG.  5   , at step  245 , the UE  201  receives a UE Configuration Update Command to inform the UE  201  that it should not transmit data for PDU sessions associated with S-NSSAI y . Alternatively, the PDU Session Modification procedure may be triggered and used to inform the UE  201  that it should not transmit data for the PDU Sessions. A cause code associated with the procedure maybe used to indicate to the UE  201  that the PDU Session is suspended because of the UE  201 &#39;s current location. At step  246 , the UE  201  transmits a UE  201  Configuration Update Complete to confirm reception of the UE  201  Configuration Update message. At step  247 , the UE  201  reselects a cell  210  in RNA 2 . At step  248 , the UE  201  performs an RNA update procedure to inform the network that it has moved to RNA 2 . At step  249 , the RAN node, e.g. gNB in RNA 2 , sends an N2 Message to inform the AMF  207  that the UE  201  has moved to a location that supports a different set of RAN slices, e.g. 5-NSSAI y  is available. 
     At step  250 , the AMF  207  invokes the SMF&#39;s UpdateSMContext service to inform the SMF/UPF  208  that the UE  201  is able to transmit/receive data for PDU sessions associated with slices that are available, e.g. PDU sessions associated S-NSSAI y . At step  251 , the UE  201  receives a UE Configuration Update Command to inform the UE  201  that it can transmit data for PDU sessions associated with S-NSSAI y . Alternatively, the PDU Session Modification procedure may be triggered and used to inform the UE  201  that it may now transmit data for the PDU Sessions. A cause code associated with the procedure maybe used to indicate to the UE  201  that the PDU Session is suspended because of the UE  201 &#39;s current location. At step  252 , the UE  201  transmits a UE Configuration Update Complete to confirm reception of the UE Configuration Update message. At step  253 , the UE  201  commences with UL/DL data transmission and reception for PDU sessions associated with S-NSSAI y , where the DL data may include any data that was buffered by the SMF/UPF  208  while the UE  201  was in RNA 1 . UL/DL data transmission and reception for PDU sessions associated with other S-NSSAIs supported in RNA 2 , e.g. S-NSSAI x , may also occur. 
     Slice-Aware RRC Connection Establishment/Resume 
     For scenarios where the UE  201  is camped on a cell that does not support the desired slice(s), e.g. the S-NSSAI(s) that the UE  201  anticipates that it might want to access, the UE  201  may reselect a cell that does support the desired slice(s) before commencing with the RACH procedure to establish/resume the RRC connection. We refer to this as a slice-aware RRC Connection Establishment/Resume procedure. 
     In the case of MO access, the UE  201  may determine the desired slice(s) based on the application/services for which data needs to be transmitted or the slices in the Allowed NSSAI. In one aspect of the disclosed subject matter, upper layers, e.g. the NAS Layer, informs the AS of the desired slice(s), e.g. S-NSSAIs, when making a request to establish/resume an RRC connection. Alternatively, this info may be conveyed by providing the UE  201  with info about the PDU session(s) for which data needs to be transmitted and the AS may then determine the desired slice(s). And in another alternative, the desired slice(s) may be determined by the AS based on the Logical Channel(s) (LCH) or Logical Channel Group(s) (LCG) that have data available for transmission. 
     In the case of MT access, the network may inform the UE  201  of the desired slice(s) when the UE  201  is paged. The desired slice(s) may correspond to S-NSSAIs in the Allowed NSSAI, that was provided to the UE  201  during a Registration procedure, an S-NSSAI in the Configured NSSAI, etc. In one aspect of the disclosed subject matter, the Paging Message includes the S-NSSAI(s) (or SST&#39;s or SD&#39;s) associated with the PDU session(s) for which data will be transmitted for the MT call. The S-NSSAI(s) included in the Paging Message may be used by the AS directly to determine the desired slice(s). Alternatively, the AS may forward the S-NSSAI(s) (or SST&#39;s or SD&#39;s) included in the Paging Message to upper layers, thereby enabling upper layers to determine the desired slice(s) and subsequently inform the AS of the desired slice(s), e.g. S-NSSAIs, when making a request to establish/resume an RRC connection. 
     Prior to commencing with the RACH procedure to establish/resume the RRC connection, the UE  201  compares the desired slice(s) with the slice(s) supported by the serving cell, where the UE  201  may determine which slices are supported by a cell using the “Slice-Based Cell Selection and Reselection” subject matter described herein. If the UE  201  determines the serving cell does not support the desired slice(s), the UE  201  may reselect a cell that does support the desired slice(s). For scenarios where the desired slices are not supported by a single cell, the UE  201  may rank the cells in accordance with “Slice-Based Cell Selection and Reselection” subject matter described herein. 
       FIG.  6    and  FIG.  7    are illustrations of the signaling for an exemplary Slice-Aware RRC Connection Establishment/Resume procedure for MO and MT access respectively. In these examples, we assume Cell 1  and Cell 2  cover the same geographic area, thereby allowing the UE  201  to camp on either cell at its current location. Furthermore, we also assume Cell 1  does not support the desired slice, e.g. S-NSSAI x , but, Cell 2  does.  FIG.  6    is an exemplary illustration of Slice-Aware RRC Connection Establishment Procedure (MO Access). In  FIG.  6   , at step  260 , the UE  201  camps on Cell 1    221  that does not support S-NSSAI x . At step  261 , the UE  201  receives a trigger for MO access for S-NSSAI x . Upper layers may provide the AS, e.g. RRC, with one or more S-NSSAIs that correspond to the desired slice(s) when making a request to establish or resume an RRC connection. For scenarios where the MO access is initiated by the AS layer, e.g. upon triggering an RNA update while the UE  201  is in RRC_INACTIVE, the AS, e.g. RRC, may determine the desired slice(s) with or without interaction with upper layers. In one aspect of the subject matter, it may be assumed that any slice can be used for RRC signaling initiated by the AS. Therefore, the UE  201  can commence with resuming the RRC connection on the serving cell, provided the UE  201  is camped normally. 
     At step  262 , the UE  201  determines the serving cell, e.g. Cell 1 ,  221  does not support S-NSSAI x , e.g. the desired slice, and reselects Cell 2    222  that does support S-NSSAI x  At step  263 , the UE  201  performs the RRC Connection Establishment/Resume procedure with Cell 2    222 . At step  264 , the UE  201  commences with UL/DL data transmission for S-NSSAI x  with Cell 2    222 . 
       FIG.  7    is an exemplary illustration of Slice-Aware RRC Connection Establishment Procedure (MT Access). In  FIG.  7   , at step  270 , the UE  201  camps on Cell 1    221  that does not support S-NSSAI x . At step  271 , the UE  201  receives a Page for MT access for 5-NSSAI x . The Page may be initiated by the RAN or CN. The network may Page the UE  201  in one or more Tracking Areas, where the cells in a given Tracking Area that Page the UE  201  may or may not support the slice for which the MT access is intended, e.g. Cell 1    221  and Cell 2    222  in the current example may Page the UE. At step  272 , the UE  201  determines the serving cell, e.g. Cell 1    221 , does not support S-NSSAI x , e.g. the desired slice, and reselects Cell 2    222  that does support S-NSSAI x . The desired slice may be determined by the AS directly, e.g. from the S-NSSAI(s) included in the PagingRecord. Alternatively, the AS may forward the S-NSSAI(s) included in the PagingRecord to upper layers, thereby enabling upper layers to determine the desired slice(s) and subsequently inform the AS of the desired slice(s), e.g. S-NSSAI(s), when making a request to establish/resume an RRC connection in response to the Page. At step  273 , the UE  201  performs the RRC Connection Establishment/Resume procedure with Cell 2    222 . At step  274 , the UE  201  commences with UL/DL data transmission for S-NSSAI x  with Cell 2    222 . 
     In another alternative, the UE  201  may simultaneously camp on multiple cells, and then access the cell that supports the desired slice. In one aspect of the subject matter, the UE  201  monitors slice-dependent paging on multiple different cells, and the network transmits a page corresponding to a given slice only on cells that support that slice. 
     Mechanisms Associated with Scenario #2 
     To allow offloading of initial access attempts for a given slice to a specific frequency layer, the UE  201  may reselect a cell on a different frequency layer prior to commencing with the RACH procedure to establish/resume the RRC connection, where the cell reselection priority of a given frequency may be determined, at least in part, on the slice for which the RRC connection is being established/resumed. The UE  201  may be provisioned or configured with a slice-specific priority for each frequency layer on which a given slice is available. For example, the Configured NSSAI may include fields to indicate the priority of an S-NSSAI for the frequencies on which the S-NSSAI is deployed. Prior to establishing/resuming an RRC connection, a cell reselection evaluation process is triggered, where the UE  201  calculates the NR Inter-frequency and Inter-RAT cell reselection criteria using the slice-specific frequency priorities that correspond to the slice for which the RRC connection is being established/resumed. Cell reselection to a cell on a different frequency layer is subsequently performed, if a suitable cell on a higher priority frequency layer is found. 
     In another example, only a portion of the initial access traffic for a given slice may be directed to a different frequency layer. The portion of traffic to redirect to a different frequency layer may be based on some criteria or rules, e.g., the number of users of a specific type (e.g. eMBB or URLLC users in the cell or system) or the ratio of eMBB/URLLC traffic or slice traffic, initial access attempt conditions, number of initial access attempt failures, etc. For example, if number of initial access attempt failures is large, e.g. larger than a threshold, then redirect more initial access traffic to a first frequency layer, F1, otherwise redirect less traffic to F1. If the number of initial access attempt failures is smaller than a threshold, then no redirect of initial access traffic is performed. The portion of redirected traffic may be configured or indicated in e.g., broadcast, system information, higher layer signaling, RRC signaling, etc. 
       FIG.  8    is an exemplary illustration of a procedure for offloading initial access attempts for a given slice to a specific frequency layer. In this example, we assume Cell 1  and Cell 2  operate on F 1  and F 2  respectively. Furthermore, we also assume for S-NSSAI x , F 2  has a higher priority than F 1 . In  FIG.  8   , at step  281 , the UE  201  camps on Cell 1    221  operating on F 1 . At step  282 , the he UE  201  receives a trigger to establish/resume an RRC connection for 5-NSSAI x . The trigger may correspond to a request from upper layers to suspend/resume an RRC connection for MO access or a Page from the network requesting the UE  201  to establish/resume an RRC connection for MT access. At step  283 , the UE  201  performs Cell Re-Selection Evaluation and determines F 2  is higher priority than F 1  for S-NSSAI x  and selects a suitable cell, Cell 2 ,  222  operating of F 2 . At step  284 , the UE  201  performs the RRC Connection Establishment/Resume procedure with Cell 2    222 . At step  285 , the UE  201  commences with UL/DL data transmission for S-NSSAI x  with Cell 2    222 . 
     Mechanisms Associated with Scenario #3 
     Slice-Aware PLMN Selection 
     On request of the NAS, the UE  201  scans RF channels in the NR bands according to its capabilities to find available PLMNs. On each carrier, the UE  201  searches for the strongest cell and reads its system information, in order to find out which PLMN(s) the cell belongs. If the UE  201  can read one or several PLMN identities in the strongest cell, each found PLMN is reported to the NAS as a high quality PLMN (but without the RSRP value), provided that the following high-quality criterion is fulfilled: For an NR cell, the measured RSRP value shall be greater than or equal to −110 dBm. 
     Found PLMNs that do not satisfy the high-quality criterion but for which the UE  201  has been able to read the PLMN identities are reported to the NAS together with their corresponding RSRP values. The quality measure reported by the UE  201  to NAS shall be the same for each PLMN found in one cell. 
     To enable slice-aware PLMN selection, information that can be used to determine the slice availability for one or more PLMNs at the UEs current location may also be reported to the NAS. As discussed in the mechanisms associated with Scenario #1, network slice availability may be defined on a cell, RNA, TA, RA, or frequency layer basis. Therefore, this slice availability information (e.g., a list of available or barred slices, S-NSSAIs broadcast by the cell) may include the Cell Identity, Tracking Area Code, or RAN Area Code broadcast by the cell, the frequency of the cell, or other information. The information reported by the UE  201  to the NAS to determine slice availability is the same for each PLMN found in one cell. 
     The NAS may use the slice availability information, on its own or in combination with other information that may be reported by the UE, e.g. RSRP of the cell, when determining which PLMN to select. For example, the PLMN supporting the largest number of S-NSSAIs in the Configured NSSAI, Requested NSSAI, or Allowed NSSAI may be selected. Alternatively, the PLMN supporting the default NSSAI may be selected. Other alternatives, where the S-NSSAIs are ranked/prioritized, and the PLMN supporting the highest ranked/highest priority S-NSSAI(s) is selected can also be envisaged. 
     When PLMN selection is triggered, information about the desired slice(s), e.g. S-NSSAIs in the Configured NSSAI, S-NSSAIs in Requested NSSAI of the UEs next Registration Request, S-NSSAIs in the Allowed NSSAI, etc. may be used to control the search for available PLMNs. For example, the UE  201  may search for additional cells on a carrier based on the slices supported by the strongest cell(s), e.g. when slice-availability criterion such as the following is not fulfilled: 1) the cell supports the desired slice(s); 2) the cell supports a minimum number of desired slices; 3) the cell supports the default slice; or 4) the cell supports the highest ranked/highest priority slice(s). 
     Other alternatives, where the UE  201  considers slice-based metrics being above a certain value can also be envisaged. 
     Information about the desired slice(s) may also be used to control what information is reported to the NAS. For example, if the UE  201  can read one or several PLMN identities in the cell, each found PLMN is reported to the NAS (but without slice availability information), provided the slice-availability criterion as described herein is fulfilled. 
     Found PLMNs that do not satisfy the slice-availability criterion but for which the UE  201  has been able to read the PLMN identities may be reported to the NAS together with their corresponding slice availability information. Alternatively, such PLMNs may not be reported to the NAS. 
     The search for PLMNs may be stopped on request from the NAS. The UE  201  may optimise PLMN search by using stored information e.g. frequencies or also information on cell parameters from previously received measurement control information elements or information on slices supported by a cell. 
     Once the UE  201  has selected a PLMN, the cell selection procedure shall be performed in order to select a suitable cell of that PLMN to camp on. 
     Mechanisms Associated with Scenario #4 
     Slice-Based Barring 
     During times of high network load, it is important to ensure that traffic for a lower priority slice does not block/delay the traffic that is associated with a higher priority slice. As part of the R17 study on enhancement of RAN slicing, RAN2 has agreed to “study mechanisms to enable UE  201  fast access to the cell supporting the intended slice, including slice based cell reselection under network control and slice based RACH configuration or access barring”. 
     As described herein, the 5G System already supports some Access Control Mechanisms that can be slice based, however, these mechanisms are limited in the sense that they present a configuration challenge for the network operator. They require each UE  201  to be configured, via NAS, with access category definitions for each slice that the operator might want to bar. Furthermore, the network operator needs to maintain a record of what definitions each UE  201  has been provisioned with so that the operator will know when and if updated definitions need to be sent to the UE. 
     The following issues should be addressed in order to improve the 5G system&#39;s support of slice-based access barring. First, what events, or conditions, should trigger the network to bar UEs from a slice. Second, what mechanism is used by the network to the indicate to the UE  201  that a slice is barred and how can this indication be sent to the UE  201  without requiring the operator to provision the UE  201  with operator specific access category definitions. Third, what should the UE&#39;s behavior be in response to learning that the UE  201  is barred from a slice. 
     Furthermore, it might not be necessary, or desirable, to apply barring equally to UE&#39;s within the slice. As described herein, the network can bar a UE  201  from accessing the network based on the UE&#39;s access identity, but it is not possible for the network to bar a UE  201  from particular slices based on a UE identity. For example, it might be necessary to only bar low priority UEs from accessing a slice while allowing higher priority UEs to access a slice. The following issues may be addressed in order to add support to the 5G system for UE, group, or class-based slice-based access barring: What criteria should be used by the network and the UE  201  to determine if a UE  201  is barred from a slice? 
     The subject matter in this section assume that the RAN node is responsible for informing the UE  201  that a slice is currently barred. A RAN node may be a gNodeB or a Non-3GPP InterWorking Function (N3IWF). 
     It should be appreciated that when a slice is barred, UEs that are currently registered in the slice may still be allowed to perform activity on the slice. Examples of activity are sending and receiving data and establishing and modifying PDU sessions. A UE  201  may be considered to be registered to a slice when the slice&#39;s S-NSSAI is in the UE&#39;s Allowed NSSAI and the UE  201  is in the RM-REGISTERED state. Barring may mean that the network should not allow the UE  201  to add the slice to the UE&#39;s Allowed NSSAI. Alternatively, when a slice is barred, it may mean that no activity or only certain types of activity are barred from happening in the slice. An example of certain types of activity may be sending and receiving data and establishing and modifying PDU sessions. Other examples of activity that may be barred include performing a Random Access Procedure to establish or resume an RRC connection. It should also be appreciated that when a slice is barred, the barring might only apply to some UEs. For example, the barring might only apply to certain types, classes, or groups of UE. 
     Triggers for Slice-Based Barring 
     The RAN node may use internal logic to determine that barring should be active for a slice. The determination may be based observed conditions and on local configuration or configuration that was received from an OAM system. For example, the RAN node may determine that barring should be active for a slice when the RAN node observes that the amount of network resources that are currently being consumed by activity that is related to the slice is at, or above, a threshold. Furthermore, the RAN node might determine that the barring only applies to certain types, classes, or groups of UE. 
     The RAN node may use an indication from the OAM System or an AMF  207  to determine that barring should be active for a slice. For example, the RAN node may receive an indication from the OAM System or the AMF  207  about the state of the slice. Alternatively, the indication can come from any other network function that is responsible for monitoring the resource usage of a slice or enforcing limitations on how the resources of a slice are used. Examples of slice resources include PDU sessions and UE Registrations. The indication may indicate any of the following conditions: 1) First, the indication may indicate that the slice has reached a PDU session limit; or 2) Second, the indication may indicate that the slice has reached a UE Registration limit. 
     The indication that the slice is barred may include any combination of the following pieces of information. First, the indication may include an S-NSSAI that identifies the slice that is barred. Alternatively, only an SST or SD value may be provided to indicate to the RAN node that slices that share the SST or SD value are barred. Second, the indication may include UE identifiers or UE Group Identifiers to indicate to the RAN node the identities of the UE(s) that are barred from the slice. The absence of this information may indicate to the RAN node that the UEs are barred from accessing the slice. Third, the indication may include a cause for the barring condition. For example, the cause may indicate to the RAN node that the slice is barred because the slice has reached a limit in how many UEs are registered in the slice or the slice has reached a limit in how many PDU sessions are established within the slice. Fourth, the indication may include a time-out for the barring condition. The RAN node may assume that the barring state is no longer in place when the time-out is reached. The RAN node may use a timer to track whether the time out has been reached. If the RAN node receives a barring indication for the same slice before the time is reached, the RAN node may restart timer and continue the barring condition. Fifth, the types, classes, or groups of UE  201  that are barred, or not barred, from the slice. 
     Indicating to a UE  201  that it should consider a slice to be barred 
     When the RAN node receives an indication that a slice is barred, the RAN node will indicate to the UE  201  that the slice is barred. 
     The RAN node may transmit a sliceBarred indication in the System Information, e.g. MIB or SIB1. The sliceBarred indication will be received by UEs within range of the RAN node. The sliceBarred indication indicates to the UE  201  that one or more slices are barred in the RAN node. The MIB may also include an intraFreqReselection indication that indicates whether slice barring applies to cells on the same frequency. 
     When the UE  201  receives the sliceBarred indication, the UE  201  will initiate the process of determining whether one or more of the barred slices are slices that the UE  201  wants to attempt to access. 
     A new SIB may be defined to broadcast slice related barring information. The new SIB may be called SI-SliceInfo. SIB1 may broadcast scheduling information about the SI-SliceInfo. 
     If SIB1 indicates that the RAN node is not currently broadcasting SI-SliceInfo, the UE  201  may send an On-Demand-SI (On Demand System Information) request to the RAN node in order to request that the RAN node broadcast SI-SliceInfo. The On-Demand-SI (On Demand System Information) request may involve a RACH procedure that uses PRACH preamble(s) and PRACH resource(s) to indicate to the network that the UE  201  wants the network to broadcast SI-SliceInfo. Certain PRACH preamble(s) and PRACH resource(s) may be associated with particular S-NSSAI, SST, or SD values and the network may use this information to determine what information to include in the SI-SliceInfo broadcast. When the UE  201  receives an acknowledgment of the request, it will begin to receive SI-SliceInfo. The acknowledgment may indicate to the UE  201  that no slices are barred by the RAN node. Alternatively, SI-SliceInfo may be included in the Msg2 or Msg4. 
     SI-SliceInfo may include any combination of the following information elements. First, S-NSSAI(s) that are barred in the RAN Node. Second, SST value(s) that are barred in the RAN Node. If SST values are broadcasted, it may be an indication that S-NSSAIs with the SST value are barred. Third, SD value(s) that are barred in the RAN Node. If SD values are broadcasted, it may be an indication that S-NSSAIs with the SD value are barred. Fourth, a Barring Time that indicates how long the UE  201  should consider the corresponding S-NSSAI, SST, or SD value to be barred. A Barring Time may be provided for each S-NSSAI, SST, or SD value. Fifth, UE Identities, UE Group Identities, or UE Access Classes to which the barring information applies. When this information is present, the UE  201  may disregard the information if the UE&#39;s identity, the UE&#39;s group identity, or the UE&#39;s access class is not present. Sixth, a cause for the barring condition. For example, the cause may indicate to the UE  201  that the slice is barred because the slice has reached a limit in how many UEs are registered in the slice or the slice has reached a limit in how many PDU sessions are established within the slice. An intraFreqReselection indication that is used indicate whether or not the UE  201  should consider the S-NSSAI to be barred in cells on the same frequency. Seventh, information about what slices are available in the cell (S-NSSAIs, SSTs, or SDs). Eighth, information that might be used by the UE  201  to help the UE  201  to select a different cell that is not currently barring the slice. 
     It should be appreciated that the UE  201  may receive the SI-SliceInfo via a unicast message on the DL-SCH. This information may be sent to the UE  201  by the RAN node in a unsolicited manner (e.g. not in response to a UE  201  request), for example in the scenario where the RAN node is aware that the UE  201  is registered to a slice, determines that it is barred, and sends a unicast message to the UE  201  to indicate to the UE  201  that the slice is barred. Alternatively, the RAN node might unicast the SI-SliceInfo to the UE  201  in response to a request from the UE. The request from the UE  201  may have indicated that the UE  201  wants to check if any slices are barred and may indicate the slice names. The request from the UE  201  might be unrelated to barring and the RAN node might include the SI-SliceInfo in the response. 
     If the UE  201  is RM-DEREGISTERED and it determines that it should consider one or more slices are barred by a RAN node, the UE  201  may check whether any of the barred slices are in the UE&#39;s Configured NSSAI or in the Mapping Of Configured NSSAI that is associated with the PLMN. Then the UE  201  may choose to consider the RAN node to be lower in priority and go about checking other RAN nodes to see if it is possible to connect to a different RAN which does not consider slices that are in the UE&#39;s Configured NSSAI or Mapping Of Configured NSSAI to be barred. The other RAN nodes may be associated with other PLMNs, Alternatively, the UE  201  may choose to connect to the RAN by sending a Registration request to the network and not attempting to register with the barred S-NSSAI&#39;s. In other words, the UE  201  may send a Registration Request to the RAN Node and not include a barred S-NSSAI in the Requested NSSAI of the Registration Request. The UE  201  may periodically check System Information broadcast by the RAN node to see if the barred S-NSSAI is still barred. Checking the System Information broadcast by the RAN node to see if the barred S-NSSAI is still barred may be done as described herein. When the UE  201  sees that the S-NSSAI is no longer barred, the UE  201  may choose to send a Registration Request to the RAN Node with the formerly barred S-NSSAI in the Requested NSSAI. 
     If the UE  201  is RM-REGISTERED and it determines that it should consider one or more slices are barred by the RAN node, the UE  201  may check whether any of the barred S-NSSAI(s) are in the UE&#39;s Allowed NSSAI. If a barred S-NSSAI is in the UE&#39;s Allowed NSSAI, then the UE  201  may perform any combination of the following actions: First, when the UE  201  evaluates URSP rules, the UE  201  may consider any RSD that includes the S-NSSAI to be invalid while barred. Second, the UE  201  may deregister from the slice by sending a Registration Request to the network with a Request NSSAI that does not include the barred S-NSSAI(s). Third, the UE  201  may release any PDU Session that are associated with the barred S-NSSAI(s). 
     It should be noted that when the UE  201  determines whether it should consider one or more slices to be barred by the RAN node, it may need to consider what types, classes, or groups of UEs are barred from the slice and determine if the UE  201  is part of one or more of the types, classes, or groups of UEs that are barred. The UE  201  may only consider the slice barred if the UE  201  determines that it is part of one or more of the types, classes, or groups of UEs that are barred from the slice. As described herein, the UE  201  may use broadcasted information to determine what types, classes, or groups of UEs that are barred. The UE  201  may determine what types, classes, or groups the UE  201  belongs within the slice based on any combination of the following criteria. First, the UE  201  may be configured with the types, classes, or groups the UE  201  belongs within the slice via NAS signaling. Second, information in the UE&#39;s SIM card that was configured via SMS, NAS, or OMA DM signaling may indicate the types, classes, or groups the UE  201  belongs within the slice. For example, the SIM card may be programmed with slice specific class, group, or type information for the UE. For example, this information may indicate to the UE  201  that it is considered to be part of a low priority group within the slice. Third, the Configured NSSAI, or Mapping of Configured NSSAI, that was received by the UE  201  during registration (or pre-provisioned on the UE) may include class, group, or type information for each S-NSSAI within the Configured NSSAI. Fourth, the UE  201  may be configured with the types, classes, or groups the UE  201  belongs within the slice when the UE  201  establishes a PDU Session within the slice. 
       FIG.  9    illustrates an example of how the UE  201  may learn that a slice is barred and what actions that UE  201  might take after learning that a slice is barred. 
     In step  291  of  FIG.  9   , the RAN Node broadcasts an indication that one or more slices are considered barred by the RAN node. This is further described herein. 
     In step  292  of  FIG.  9   , the UE  201  requests more information from the RAN node in order to determine what slices (e.g. S-NSSAIs) are barred. This is further described herein. 
     In step  293  of  FIG.  9   , the RAN node acknowledges the UE&#39;s request for more information about what slices (e.g. S-NSSAIs) are barred. This is further described herein. 
     In step  294  of  FIG.  9   , the UE  201  receives more information about what slices (e.g. S-NSSAIs) are barred. For example, the information may be the S-NSSAI&#39;s, SSTs, SDs that are barred. The information may also include reasons, or causes, for the barring. This is further described herein. 
     In step  295  of  FIG.  9   , the UE  201  determines to select a different RAN node. The UE  201  would then restart at step  1  with a different RAN node. This is further described herein. 
     In step  296  of  FIG.  9   , after determining that a slice is barred, the UE  201  may consider any RSD that includes the S-NSSAI to be invalid while barred. 
     In step  297 -step  298  of  FIG.  9   , if the UE  201  chose to continue connecting to the network via this RAN node, the UE  201  sends a Registration Update to the AMF. The Registration Update may not include any of the S-NSSAIs that were identified as barred in step  294 . The AMF  207  will respond to the request and the barred S-NSSAIs will not be included in the allowed NSSAI that is provide to the UE. This is further described herein. 
     In step  299 -step  300  of  FIG.  9   , if the UE  201  chose to continue connecting to the network via this RAN node, the UE  201  sends a PDU Session Release messages to the AMF  207  for any PDU Sessions that are associated with any of the S-NSSAIs that were identified as barred in step  294  and receives a release response. This is further described herein. 
     Handling Registration Request for Barred Slices 
     When the UE  201  sends a NAS Registration Request to a RAN Node the Registration Request may be included in another RRC Message (e.g. an RRC Connection Establishment Request), the Requested NSSAI may be included in the AS signaling (e.g. RRC Connection Establishment Request). The RAN Node uses the Requested NSSAI in AMF Selection. The UE  201  may include an S-NSSAI in the Requested NSSAI that is barred. When the RAN Node detects that the UE  201  included an S-NSSAI in the Requested NSSAI that is barred, the RAN Node may take the following actions. 
     The RAN Node will not consider the barred S-NSSAI during AMF selection. Instead, it will proceed with AMF selection and only consider S-NSSAI&#39;s that are in the Requested NSSAI and that are not barred. 
     Once an AMF  207  is selected by the RAN Node, the RAN Node may send an N2 message to the AMF. The N2 message may include the Registration Request from the UE  201  and N2 Parameters. The N2 Parameters may include information that indicates that certain S-NSSAI&#39;s in the Requested NSSAI should be rejected by the AMF. The N2 Parameters may further indicate what types, groups, or classes of UEs are barred from the S-NSSAI. The information may further indicate a cause or reason for the rejection. For example, the information may indicate that S-NSSAI #1 should be rejected by the AMF  207  because it is barred by the RAN Node. 
     When the AMF  207  receives the N2 message and the N2 Parameters indicate a certain S-NSSAI(s) should be rejected, the AMF  207  will not consider allowing the indicated S-NSSAIs in the Requested NSSAI. The AMF  207  will include the indicated S-NSSAIs in the Rejected S-NSSAI in the Registration response that is sent to the UE  201 . The AMF  207  may provide a cause code to the UE  201  to indicate why each S-NSSAI was rejected. The cause code may be determined by the AMF  207  based on the cause code that was provided by the RAN Node in the N2 Parameters. The determined cause code may indicate to the UE  201  that the S-NSSAI is barred. If the AMF  207  determines that no S-NSSAI can be provided in the Allowed NSSAI, the AMF  207  will reject the Registration Request. 
     If the N2 Parameters indicated that only certain types, groups, or classes of UEs are barred from the S-NSSAI (or are not barred), then the AMF  207  may check the UE&#39;s subscription, or context information, to determine if barring applies to the UE  201  and if the S-NSSAI should be included in the UE&#39;s Allowed NSSAI. 
     Improving the Efficiency of the Existing Unified Access Control Mechanism 
     As described herein, the Network Operator may need to keep track of what Access Category Definitions have been sent to the UE  201 . Furthermore, the UE  201  may, based on implementation, delete the Access Category Definitions that are associated with a PLMN (e.g. due to a reset of the device or because the UE  201  did not attach to the PLMN for a long time). 
     Interaction between the UE  201  and the Network can be made to be more efficient if the Operator-defined access category definitions Information Element that is sent to the UE  201  during registration, or during a configuration update, were updated to include a unique identifier that identifies the set of definitions that are carried in the IE. Each time the UE  201  registers with the network, the UE  201  may provide this identifier in the Registration Request message as a way of indicating to the network that the UE  201  still has the Operator-defined access category definitions stored for the PLMN. 
     As per the Release 15 NR specification, slice specific access control can be somewhat done through the appropriate operator defined slice specific access category configuration and access baring parameters configuration. However, as a UE  201  roams around, the meaning of operator defined access category might change from one geographical area to another leading to a miss match between the expected level of service or access privilege and the service level or access privilege level provided by the network. Furthermore, as 5G systems are being designed to support requirements (such as security and privacy requirements) from different vertical domain of industries or applications, it will likely be desirable in some cases to have well defined default behaviors in terms of slice provisioning across operators&#39; networks and across devices when accessing the network or in terms of quality of service expectation once connected to the network. For example, taking the case of eHealth use cases, certain applications may require plug and play from one network to the other wherein the allowed network slice(s) are preconfigured into the UE  201  for the purpose of access control and traffic isolation. It should be noted such devices might be reduced capability devices with build-in preconfigured service capabilities. It is therefore proposed to have rules captures in 3GPP specification, that specifies mapping between a slices and access category or access category number for certain pre-defined or specified slice, wherein the access category number is a unique identifier assigned to an access category. The UE  201  uses such mapping to identify an access category, to be used to perform access control and access baring check when initiating an access to a network slice pertaining to one of the specified rules. Example of specified rules for UE  201  to determine an access category for an access attempt pertaining to a specific slice is shown in Table 6. It should be appreciated that these rules may be provisioned into the UE  201  by the network via NAS signaling. These rules may also be provisioned into the by the network via Over-The-Air Device Management (OTA-DM) signaling. They may also be preconfigured into the UE  201  or be configured into the UE  201  via RRC signaling. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Rules to Determine an Access Category for an Access Attempt Pertaining to a Specific Slice 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Type of access 
                   
                 Access 
               
               
                 Rul e# 
                 Slice ID 
                 attempt 
                 Requirements to be met 
                 Category 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 1 
                 NSSAI 1 or 
                 Response to paging or 
                 Access attempt is for MT 
                 8 
               
               
                   
                 S-NSSAI 1 or 
                 NOTIFICATION over 
                 access, or handover of 
               
               
                   
                 SST 1 or SD 1 
                 non-3GPP access; 
                 ongoing MMTEL voice call, 
               
               
                   
                   
                 5GMM connection 
                 MMTEL video call or SMSoIP 
               
               
                   
                   
                 management procedure 
                 from non-3GPP access 
               
               
                   
                   
                 initiated for the 
               
               
                   
                   
                 purpose of 
               
               
                   
                   
                 transporting an LPP 
               
               
                   
                   
                 message without an 
               
               
                   
                   
                 ongoing 5GC-M0-LR 
               
               
                   
                   
                 procedure; 
               
               
                   
                   
                 Access attempt to 
               
               
                   
                   
                 handover of ongoing 
               
               
                   
                   
                 MMTEL voice call, 
               
               
                   
                   
                 MMTEL video call or 
               
               
                   
                   
                 SMSoIP from non-3GPP 
               
               
                   
                   
                 access 
               
               
                 2 
                 NSSAI 2 or 
                 Emergency 
                 UE is attempting access 
                 10 
               
               
                   
                 S-NSSAI 2 or 
                   
                 for an emergency session 
               
               
                   
                 SST 2 or SD2 
               
               
                 3 
                 NSSAI 3 or 
                 Access attempt for 
                 (a) UE is configured for 
                 11 
               
               
                   
                 S-NSSAI 3 or 
                 delay tolerant 
                 NAS signalling low priority 
               
               
                   
                 SST 3 or SD 3 
                 service 
                 or UE supporting S1 mode is 
               
               
                   
                   
                   
                 configured for EAB (see the 
               
               
                   
                   
                   
                 “ExtendedAccessBarring” leaf 
               
               
                   
                   
                   
                 of NAS configuration MO in 
               
               
                   
                   
                   
                 3GPP TS 24.368 V15.1.0 [10] 
               
               
                   
                   
                   
                 or 3GPP TS 31.102 V15.7.0 
               
               
                   
                   
                   
                 [11]) where “EAB override” 
               
               
                   
                   
                   
                 does not apply, and 
               
               
                   
                   
                   
                 (b): the UE received one of 
               
               
                   
                   
                   
                 the categories a, b or c as 
               
               
                   
                   
                   
                 part of the parameters for 
               
               
                   
                   
                   
                 unified access control in 
               
               
                   
                   
                   
                 the broadcast system 
               
               
                   
                   
                   
                 information, and the UE is 
               
               
                   
                   
                   
                 a member of the broadcasted 
               
               
                   
                   
                   
                 category in the selected PLMN 
               
               
                   
                   
                   
                 or RPLMN/equivalent PLMN 
               
               
                 4 
                 NSSAI 4 or 
                 MO IMS 
                 Access attempt is for MO IMS 
                 11 
               
               
                   
                 S-NSSAI 4 or 
                 registration related 
                 registration related signalling 
               
               
                   
                 SST 4 or SD4 
                 signalling 
                 (e.g. IMS initial registration, 
               
               
                   
                   
                   
                 re-registration, subscription 
               
               
                   
                   
                   
                 refresh) 
               
               
                   
                   
                   
                 or for NAS signalling 
               
               
                   
                   
                   
                 connection recovery during 
               
               
                   
                   
                   
                 ongoing procedure for MO 
               
               
                   
                   
                   
                 IMS registration related 
               
               
                   
                   
                   
                 signalling 
               
               
                 5 
                 NSSAI 5 or 
                 MO MMTel voice 
                 Access attempt is for MO 
                 12 
               
               
                   
                 S-NSSAI 5 or 
                 call 
                 MMTel voice call 
               
               
                   
                 SST 5 or SD 5 
                   
                 or for NAS signalling 
               
               
                   
                   
                   
                 connection recovery during 
               
               
                   
                   
                   
                 ongoing MO MMTel voice call 
               
               
                 6 
                 NSSAI 6 or 
                 MO MMTel video 
                 Access attempt is for MO 
                 13 
               
               
                   
                 S-NSSAI 6 or 
                 call 
                 MMTel video call 
               
               
                   
                 SST 6 or SD 6 
                   
                 or for NAS signalling 
               
               
                   
                   
                   
                 connection recovery during 
               
               
                   
                   
                   
                 ongoing MO MMTel video call 
               
               
                 7 
                 NSSAI 7 or 
                 MO SMS over 
                 Access attempt is for MO SMS 
                 14 
               
               
                   
                 S-NSSAI 7 or 
                 NAS or MO 
                 over NAS or MO SMS over 
               
               
                   
                 SST 7 or SD 7 
                 SMSoIP 
                 SMSoIP transfer 
               
               
                   
                   
                   
                 or for NAS signalling 
               
               
                   
                   
                   
                 connection recovery during 
               
               
                   
                   
                   
                 ongoing MO SMS or SMSoIP 
               
               
                   
                   
                   
                 transfer 
               
               
                 8 
                 NSSAI 8 or 
                 UE NAS initiated 
                 Access attempt is for MO 
                 15 
               
               
                   
                 S-NSSAI 8 or 
                 5GMM specific 
                 signalling 
               
               
                   
                 SST 8 or SD 8 
                 procedures 
               
               
                 9 
                 NSSAI 9 or 
                 Mobile originated 
                 Access attempt is for mobile 
                 16 
               
               
                   
                 S-NSSAI 9 or 
                 location request 
                 originated location request 
               
               
                   
                 SST 9 or SD 9 
               
               
                 10 
                 NSSAI 10 or 
                 Mobile originated 
                 Access attempt is for mobile 
                 17 
               
               
                   
                 S-NSSAI 10 or 
                 signalling 
                 originated signalling 
               
               
                   
                 SST 10 or SD 10 
                 transaction 
                 transaction towards the PCF 
               
               
                   
                   
                 towards the PCF 
               
               
                 11 
                 NSSAI 11 or 
                 UE NAS initiated 
                 Access attempt is for MO data 
                 18 
               
               
                   
                 S-NSSAI 11 or 
                 5GMM connection 
               
               
                   
                 SST 11 or SD 11 
                 management 
               
               
                   
                   
                 procedure or 
               
               
                   
                   
                 5GMM NAS 
               
               
                   
                   
                 transport 
               
               
                   
                   
                 procedure 
               
               
                 12 
                 NSSAI 12 or 
                 An uplink user 
                 No further requirement is to be 
                 19 
               
               
                   
                 S-NSSAI 12 or 
                 data packet is to be 
                 met 
               
               
                   
                 SST 12 or SD 12 
                 sent for a PDU 
               
               
                   
                   
                 session with 
               
               
                   
                   
                 suspended user- 
               
               
                   
                   
                 plane resources 
               
               
                 13 
                 NSSAI 13 or 
                 UE NAS initiated 
                 Access attempt is for MO 
                 20 
               
               
                   
                 S-NSSAI 13 or 
                 5GMM connection 
                 Exception data 
               
               
                   
                 SST 13 or SD 13 
                 management 
               
               
                   
                   
                 procedure or 
               
               
                   
                   
                 5GMM NAS 
               
               
                   
                   
                 transport 
               
               
                   
                   
                 procedure 
               
               
                   
               
            
           
         
       
     
     1.1.1 Slice-Based Random Access 
     Random access resources (e.g. RACH preambles, RACH transmission resources in time and frequency domain) may be (pre)configured or reserved by specification with mapping into specific network slice or group of slices. In other words, the random access resources may be partitioned and (pre)configured into the UE  201  on network slice basis. During the random access procedure, the UE  201  may indicate to the network, the requested slice or group of slices by using a random-access resource that maps to the desired or intended or requested network slice or group slice. Such feature might be beneficial for example in support of random access prioritization in the network or in support of congestion control by the network. The UE  201  might also use this mechanism to request from the network, slice specific resource grants for uplink data transmission, particularly for use cases such as Early Data Transmission or small data transmission where the UE  201  might request a grant to transmit small size data without a full transition into RRC connected state. 
     Service-Based Partitioning of RACH Resources 
     RACH resources may be grouped or partitioned into several groups or partitions, each group or partition may be associated with one service type or slice(s). For example, one RACH resource group or partition may be associated with eMBB service type or slice(s), another RACH resource group or partition may be associated with another service type or slice(s), e.g., mMTC, while yet another RACH resource group or partition may be associated with yet another service type or slice(s), e.g., URLLC. The network may allocate resources for the different types based on the expected initial access traffic for a given type. 
     When UE  201  perform initial access or random access, UE  201  may use RACH resource group to implicitly indicate to gNB and network which service type or slice(s) it desires. 
     In addition, different RO groups or partitions may be associated with different payload sizes, TBSs or grant sizes. For example, when UE  201  transmit PRACH on one RO group or partition, the UE  201  is requesting or indicating a large payload, TBS or grant, another RO group or partition may request another payload size, TBS or grant size e.g., medium payload, TBS or grant size while the third RO group or partition may request a small payload, TBS, or grant size. 
     Depending on the payload, TBS and grant granularity, RO may be grouped or partitioned into multiple e.g., more than three groups or partitions to indicate different service types or slices. 
     Yet another consideration, different RO groups or partitions may be associated with priority. UE  201  may use different RO groups or partitions to indicate different priorities or the like. 
     Slice-Based Prioritized Random Access 
     Slice type-based RACH configurations may be used. For example, one slice type may have higher initial transmit preamble power than the other slice type. This may enable higher priority slice type may succeed better for random access than lower priority slice type, and vice versa. Another example is that higher priority slice type may use much larger power ramping step size than lower priority slice type. On the other hand, lower priority slice type may use much smaller power ramping step size than higher priority slice type. Yet another approach may be to use smaller random backoff counter or window for high priority slice type than low priority slice type, and vice versa. Other similar approaches, extension or the like may also be considered and used. 
     Slice-Based Paging 
     A slice-based paging mechanism may be defined wherein, the UE  201  behavior in terms of paging monitoring, UE  201  addressing for paging message notification or paging message content is specific to slice or group of slices the UE  201  is interested in. A UE  201  may be configured with multiple applications, each of which may be mapped to different network slice configurations and requirements. Depending on factors such as the application the UE  201  is interested in during any given period of time and the UE subscription profile, the UE  201  may autonomously select, or configured by the network (for example a core network function or node such as the AMF, or base station function or node such as gNB) or select in coordination with the network, a slice or a group of slices for paging monitoring and reception purposes. Such slice or set of slices may be a subset of the slices the UE  201  may use or is allowed to use in the current serving cell for e.g. the cell the UE  201  is currently camped on. 
     Slice-based paging configuration: In support of slice-based paging mechanism, the UE  201  may be configured with paging configuration parameters specific to a network slice or to a set of network slices. Slice specific paging configuration parameters may include one or more of the following parameters: Slice specific T, Slice specific N, Slice specific N S , Slice specific PF, Slice specific UE_ID, Slice specific UE specific DRX value(s), Slice specific Default DRX value, or Slice specific first-PDCCH-MonitoringOccasionOfPO.
         Slice specific T: Slice specific DRX cycle of the UE  201  (T is determined by the shortest of UE specific DRX value(s), if configured by RRC or upper layers, slice specific UE specific DRX value(s) if configured by RRC or upper layers, default DRX value broadcast in system information, and a slice specific default DRX value broadcast in system information. In RRC_IDLE state, if UE specific DRX is not configured by upper layers, the default value is applied, similarly if slice specific UE specific DRX is not configured by upper layers, the slice specific default value is applied).   Slice specific N: slice specific number of total paging frames in slice specific T   Slice specific N S : slice specific number of paging occasions for a slice specific PF   Slice specific PF_offset: slice specific offset used for slice specific PF determination   Slice specific UE_ID: slice specific 5G-S-TMSI mod 1024   Slice specific UE specific DRX value(s)   Slice specific Default DRX value   Slice specific first-PDCCH-MonitoringOccasionOfPO       

     Slice-Based Paging Monitoring, UE Addressing for Paging and Paging Content 
     The UE  201  may use one or more of the slice-based paging configuration parameters configured into the UE  201  for the calculation of slice specific Paging Frame (PF) and slice specific index i_s of the Paging Occasion (PO). PO may be slice specific, and how many consecutive PDCCH monitoring occasions constitute a PO may be configured into the UE  201  on slice basis. The parameter SeachSpaceId (as defined in 38.304) configured into the UE  201  for pagingSearchSpace or the pagingSearchSpace may be slice specific. 
     The Radio Network Temporary Identifier (RNTI) used by the UE  201  to identify, and differentiate paging message from other messages received from the network, for example the P-RNTI may be specific to a slice or group of slice. A slice specific RNTI such as P-RNTI may be used by the network to address paging messages to a UE. A UE  201  may use slice specific P-RNTI to monitor, identify or differentiate paging messages intended for a specific network slice. A paging message may also include one or more slice identifiers. A UE  201  may use such a slice identifier to identify or differentiate paging messages intended for a specific network slice. 
       FIG.  10    illustrates an exemplary method flow associated with the RAN slicing subject matter disclosed herein. At step  302 , there is a determination of whether network slice configuration was received (e.g., via RRC signaling). If received, then at step  303  there is a determination whether the UE is in RRC_IDLE. If in RRC_IDLE, then at step  304  network slice-based RRC_IDLE procedures are performed. If at step  303  the UE is not in RRC_IDLE then at step  305  there is a determination if the UE is in RRC_INACTIVE. If the UE is in RRC_INACTIVE then at step  306  network slice-based RRC_INACTIVE procedures are performed. 
     With continued to  FIG.  10   , if network slice configuration is not received, then at step  307  there is a determination if the UE is in RRC_IDLE. If the UE is in RRC_IDLE, then at step  308  legacy RRC_IDLE procedures are performed. With reference to step  307 , if UE is not in RRC_IDLE, then at step  309  there is a determination of whether the UE is RRC_INACTIVE. If the UE is in RRC_INACTIVE then legacy RRC_INACTIVE procedures are performed. 
       FIG.  11    illustrates an exemplary method flow associated with RAN slicing. At step  321 , a device may monitor triggers for RRC_IDLE mode procedures. Based on a network slice configuration and a trigger any of step  322  (UE reselects to a new tracking area), step  324  (cell selection or cell reselection triggered), step  326  (RRC connection establishment triggered), step  331  (PLMN selection triggered), or step  333  (perform slice-based core network paging monitoring and slice-based paging reception) may be the triggered. Respectively, once triggered, there may be procedures performed, such as step  323  (perform slice registration update via registration request procedure), step  325  (perform network slice-based cell selection or reselection procedure), step  327  (perform slice based access control procedure), or step  332  (perform network slice-based cell selection or reselection procedure). Following step  327 , if access is allowed at step  328 , then perform slice-based access random access procedure at step  329 , and then perform slice-based RRC connection establishment procedure for step  330 . 
       FIG.  12    illustrates an exemplary method flow associated with RAN slicing. At step  341 , triggers for RRC_INACTIVE mode procedures may be monitored. Based on a network slice configuration and a trigger any of step  342  (UE reselects to a new RNA), step  344  (cell selection or reselection triggered), step  346  (RRC connection resume triggered), step  351  (PLMN selection triggered), or step  353  (performed slice-based radio access network paging monitoring and slice based paging reception). Respectively, once triggered, there may be procedures performed, such as step  343  (Slice Registration Update via RAN Notification Area (RNA) Update Procedure), step  345  (Perform Network Slice-based Cell Selection or Cell reselection procedure), step  347  (Perform Slice-based Access Control procedure), or step  352  (Perform Network Slice-based Cell Selection or Cell reselection procedure). Following step  347 , if access is allowed at step  348 , then perform slice-based access random access procedure at step  349 , and then perform slice-based RRC connection resume procedure for step  350 . 
     It is understood that the entities performing the steps illustrated herein, such as  FIG.  1   - FIG.  9   , may be logical entities. The steps may be stored in a memory of, and executing on a processor of, a device, server, or computer system such as those illustrated in  FIG.  14 A - FIG.  14 G . Skipping steps, combining steps, or adding steps between exemplary methods disclosed herein (e.g.,  FIG.  1   - FIG.  9   ) is contemplated. Table 7 discloses abbreviations that may be used herein. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Abbreviations and Definitions 
               
            
           
           
               
               
            
               
                 Abbreviations 
                 Definitions 
               
               
                   
               
               
                 5G 
                 Fifth Generation 
               
               
                 5GC 
                 5G Core Network 
               
               
                 5GS 
                 5G System 
               
               
                 AMF 
                 Access and Mobility Management Function 
               
               
                 AS 
                 Access Stratum 
               
               
                 CD-SSB 
                 Cell Defining SSB 
               
               
                 CM 
                 Connection Management 
               
               
                 CMAS 
                 Commercial Mobile Alert System 
               
               
                 CN 
                 Core Network 
               
               
                 CRS-NSSAI 
                 Cell Reselection Network Slice 
               
               
                   
                 Selection Assistance Information 
               
               
                 DNN 
                 Data Network Name 
               
               
                 eMBB 
                 Enhanced Mobile Broadband 
               
               
                 ETWS 
                 Earthquake and Tsunami Warning System 
               
               
                 gNB 
                 NR NodeB 
               
               
                 IoT 
                 Internet of Things 
               
               
                 LCG 
                 Logical Channel Group 
               
               
                 LCH 
                 Logical Channel 
               
               
                 MAC 
                 Medium Access Control 
               
               
                 MioT 
                 Massive IOT 
               
               
                 MNO 
                 Mobile Network Operator 
               
               
                 MO 
                 Mobile Originated 
               
               
                 MT 
                 Mobile Terminated 
               
               
                 N3IWF 
                 Non-3GPP InterWorking Functions 
               
               
                 NAS 
                 Non-Access Stratum 
               
               
                 NCL 
                 Neighbor Cell List 
               
               
                 NG-RAN 
                 Next Generation Radio Access Network 
               
               
                 NR 
                 New Radio 
               
               
                 NSSAI 
                 Network Slice Selection Assistance Information 
               
               
                 OAM 
                 Operations Administration and Maintenance 
               
               
                 PCI 
                 Physical Cell ID 
               
               
                 PDCP 
                 Packet Data Convergence Protocol 
               
               
                 PDU 
                 Protocol Data Unit 
               
               
                 PF 
                 Paging Frame 
               
               
                 PLMN 
                 Public Land Mobile Network 
               
               
                 PO 
                 Paging Occasion 
               
               
                 PRACH 
                 Physical Random Access Channel 
               
               
                 P-RNTI 
                 Paging Radio Network Temporary Identifier 
               
               
                 QoS 
                 Quality of Service 
               
               
                 RLC 
                 Radio Link Control 
               
               
                 SDAP 
                 Service Data Adaptation Protocol 
               
               
                 RA 
                 Registration Area 
               
               
                 RACH 
                 Random Access Channel 
               
               
                 RAN 
                 Radio Access Network 
               
               
                 RAT 
                 Radio Access Technology 
               
               
                 REDCAP 
                 Reduced Capability 
               
               
                 RM 
                 Registration Management 
               
               
                 RNA 
                 RAN Notification Area 
               
               
                 RNTI 
                 Radio Network Temporary Identifier 
               
               
                 RRC 
                 Radio Resource Control 
               
               
                 RRM 
                 Radio Resource Management 
               
               
                 RSRP 
                 Reference Signal Received Power 
               
               
                 RSRQ 
                 Reference Signal Received Quality 
               
               
                 SD 
                 Slice Differentiator 
               
               
                 SI 
                 System Information 
               
               
                 SLA 
                 Service Level Agreement 
               
               
                 S-NSSAI 
                 Single-Network Slice Selection Assistance Information 
               
               
                 SSB 
                 Synchronization Signal/PBCH Block 
               
               
                 SMF 
                 Session Management Function 
               
               
                 SST 
                 Slice/Service Type 
               
               
                 TA 
                 Tracking Area 
               
               
                 TDD 
                 Time Division Duplex 
               
               
                 UE 
                 User Equipment 
               
               
                 UPF 
                 User Plane Function 
               
               
                 URLLC 
                 Ultra-Reliable Low-Latency Communication 
               
               
                 V2X 
                 Vehicle-to-Everything 
               
               
                 VPLMN 
                 Visited Public Land Mobile Network 
               
               
                   
               
            
           
         
       
     
       FIG.  13    illustrates an exemplary display (e.g., graphical user interface) that may be generated based on the methods, systems, and devices of RAN slicing, as discussed herein. Display interface  901  (e.g., touch screen display) may provide text in block  902  associated with RAN slicing. Progress of any of the steps (e.g., sent messages or success of steps) discussed herein may be displayed in block  902 . In addition, graphical output  902  may be displayed on display interface  901 . Graphical output  903  may be the topology of the devices implementing the methods, systems, and devices of RAN slicing, a graphical output of the progress of any method or systems discussed herein, or the like. 
     The 3rd Generation Partnership Project (3GPP) develops technical standards for cellular telecommunications network technologies, including radio access, the core transport network, and service capabilities—including work on codecs, security, and quality of service. Recent radio access technology (RAT) standards include WCDMA (commonly referred as 3G), LTE (commonly referred as 4G), LTE-Advanced standards, and New Radio (NR), which is also referred to as “5G”. 3GPP NR standards development is expected to continue and include the definition of next generation radio access technology (new RAT), which is expected to include the provision of new flexible radio access below 7 GHz, and the provision of new ultra-mobile broadband radio access above 7 GHz. The flexible radio access is expected to include a new, non-backwards compatible radio access in new spectrum below 6 GHz, and it is expected to include different operating modes that may be multiplexed together in the same spectrum to address a broad set of 3GPP NR use cases with diverging requirements. The ultra-mobile broadband is expected to include cmWave and mmWave spectrum that will provide the opportunity for ultra-mobile broadband access for, e.g., indoor applications and hotspots. In particular, the ultra-mobile broadband is expected to share a common design framework with the flexible radio access below 7 GHz, with cmWave and mmWave specific design optimizations. 
     3GPP has identified a variety of use cases that NR is expected to support, resulting in a wide variety of user experience requirements for data rate, latency, and mobility. The use cases include the following general categories: enhanced mobile broadband (eMBB) ultra-reliable low-latency Communication (URLLC), massive machine type communications (mMTC), network operation (e.g., network slicing, routing, migration and interworking, energy savings), and enhanced vehicle-to-everything (eV2X) communications, which may include any of Vehicle-to-Vehicle Communication (V2V), Vehicle-to-Infrastructure Communication (V2I), Vehicle-to-Network Communication (V2N), Vehicle-to-Pedestrian Communication (V2P), and vehicle communications with other entities. Specific service and applications in these categories include, e.g., monitoring and sensor networks, device remote controlling, bi-directional remote controlling, personal cloud computing, video streaming, wireless cloud-based office, first responder connectivity, automotive ecall, disaster alerts, real-time gaming, multi-person video calls, autonomous driving, augmented reality, tactile internet, virtual reality, home automation, robotics, and aerial drones to name a few. These use cases and others are contemplated herein. 
       FIG.  14 A  illustrates an example communications system  100  in which the methods and apparatuses of mobility signaling load reduction, such as the systems and methods illustrated in  FIG.  1    through  FIG.  9    described and claimed herein may be used. The communications system  100  may include wireless transmit/receive units (WTRUs)  102   a ,  102   b ,  102   c ,  102   d ,  102   e ,  102   f , or  102   g  (which generally or collectively may be referred to as WTRU  102  or WTRUs  102 ). The communications system  100  may include, a radio access network (RAN)  103 / 104 / 105 / 103   b / 104   b / 105   b , a core network  106 / 107 / 109 , a public switched telephone network (PSTN)  108 , the Internet  110 , other networks  112 , and Network Services  113 . Network Services  113  may include, for example, a V2X server, V2X functions, a ProSe server, ProSe functions, IoT services, video streaming, or edge computing, etc. 
     It will be appreciated that the concepts disclosed herein may be used with any number of WTRUs, base stations, networks, or network elements. Each of the WTRUs  102   a ,  102   b ,  102   c ,  102   d ,  102   e ,  102   f , or  102   g  may be any type of apparatus or device configured to operate or communicate in a wireless environment. Although each WTRU  102   a ,  102   b ,  102   c ,  102   d ,  102   e ,  102   f , or  102   g  may be depicted in  FIG.  14 A ,  FIG.  14 B ,  FIG.  14 C ,  FIG.  14 D ,  FIG.  14 E , or  FIG.  14 F  as a hand-held wireless communications apparatus, it is understood that with the wide variety of use cases contemplated for 5G wireless communications, each WTRU may comprise or be embodied in any type of apparatus or device configured to transmit or receive wireless signals, including, by way of example only, user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a tablet, a netbook, a notebook computer, a personal computer, a wireless sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, bus, truck, train, or airplane, and the like. 
     The communications system  100  may also include a base station  114   a  and a base station  114   b . In the example of  FIG.  14 A , each base stations  114   a  and  114   b  is depicted as a single element. In practice, the base stations  114   a  and  114   b  may include any number of interconnected base stations or network elements. Base stations  114   a  may be any type of device configured to wirelessly interface with at least one of the WTRUs  102   a ,  102   b , and  102   c  to facilitate access to one or more communication networks, such as the core network  106 / 107 / 109 , the Internet  110 , Network Services  113 , or the other networks  112 . Similarly, base station  114   b  may be any type of device configured to wiredly or wirelessly interface with at least one of the Remote Radio Heads (RRHs)  118   a ,  118   b , Transmission and Reception Points (TRPs)  119   a ,  119   b , or Roadside Units (RSUs)  120   a  and  120   b  to facilitate access to one or more communication networks, such as the core network  106 / 107 / 109 , the Internet  110 , other networks  112 , or Network Services  113 . RRHs  118   a ,  118   b  may be any type of device configured to wirelessly interface with at least one of the WTRUs  102 , e.g., WTRU  102   c , to facilitate access to one or more communication networks, such as the core network  106 / 107 / 109 , the Internet  110 , Network Services  113 , or other networks  112   
     TRPs  119   a ,  119   b  may be any type of device configured to wirelessly interface with at least one of the WTRU  102   d , to facilitate access to one or more communication networks, such as the core network  106 / 107 / 109 , the Internet  110 , Network Services  113 , or other networks  112 . RSUs  120   a  and  120   b  may be any type of device configured to wirelessly interface with at least one of the WTRU  102   e  or  102   f , to facilitate access to one or more communication networks, such as the core network  106 / 107 / 109 , the Internet  110 , other networks  112 , or Network Services  113 . By way of example, the base stations  114   a ,  114   b  may be a Base Transceiver Station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a Next Generation Node-B (gNode B), a satellite, a site controller, an access point (AP), a wireless router, and the like. 
     The base station  114   a  may be part of the RAN  103 / 104 / 105 , which may also include other base stations or network elements (not shown), such as a Base Station Controller (BSC), a Radio Network Controller (RNC), relay nodes, etc. Similarly, the base station  114   b  may be part of the RAN  103   b / 104   b / 105   b , which may also include other base stations or network elements (not shown), such as a BSC, a RNC, relay nodes, etc. The base station  114   a  may be configured to transmit or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown). Similarly, the base station  114   b  may be configured to transmit or receive wired or wireless signals within a particular geographic region, which may be referred to as a cell (not shown) for methods, systems, and devices of RAN slicing, as disclosed herein. Similarly, the base station  114   b  may be configured to transmit or receive wired or wireless signals within a particular geographic region, which may be referred to as a cell (not shown). The cell may further be divided into cell sectors. For example, the cell associated with the base station  114   a  may be divided into three sectors. Thus, in an example, the base station  114   a  may include three transceivers, e.g., one for each sector of the cell. In an example, the base station  114   a  may employ multiple-input multiple output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell. 
     The base stations  114   a  may communicate with one or more of the WTRUs  102   a ,  102   b ,  102   c , or  102   g  over an air interface  115 / 116 / 117 , which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface  115 / 116 / 117  may be established using any suitable radio access technology (RAT). 
     The base stations  114   b  may communicate with one or more of the RRHs  118   a ,  118   b , TRPs  119   a ,  119   b , or RSUs  120   a ,  120   b , over a wired or air interface  115   b / 116   b / 117   b , which may be any suitable wired (e.g., cable, optical fiber, etc.) or wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface  115   b / 116   b / 117   b  may be established using any suitable radio access technology (RAT). 
     The RRHs  118   a ,  118   b , TRPs  119   a ,  119   b  or RSUs  120   a ,  120   b , may communicate with one or more of the WTRUs  102   c ,  102   d ,  102   e ,  102   f  over an air interface  115   c / 116   c / 117   c , which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface  115   c / 116   c / 117   c  may be established using any suitable radio access technology (RAT). 
     The WTRUs  102   a ,  102   b ,  102   c , 102   d ,  102   e , or  102   f  may communicate with one another over an air interface  115   d / 116   d / 117   d , such as Sidelink communication, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air interface  115   d / 116   d / 117   d  may be established using any suitable radio access technology (RAT). 
     The communications system  100  may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station  114   a  in the RAN  103 / 104 / 105  and the WTRUs  102   a ,  102   b ,  102   c , or RRHs  118   a ,  118   b ,TRPs  119   a ,  119   b  and RSUs  120   a ,  120   b , in the RAN  103   b / 104   b / 105   b  and the WTRUs  102   c ,  102   d ,  102   e ,  102   f , may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface  115 / 116 / 117  or  115   c / 116   c / 117   c  respectively using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) or High-Speed Uplink Packet Access (HSUPA). 
     In an example, the base station  114   a  and the WTRUs  102   a ,  102   b ,  102   c , or RRHs  118   a ,  118   b , TRPs  119   a ,  119   b , or RSUs  120   a ,  120   b  in the RAN  103   b / 104   b / 105   b  and the WTRUs  102   c ,  102   d , may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface  115 / 116 / 117  or  115   c / 116   c / 117   c  respectively using Long Term Evolution (LTE) or LTE-Advanced (LTE-A). In the future, the air interface  115 / 116 / 117  or  115   c / 116   c / 117   c  may implement 3GPP NR technology. The LTE and LTE-A technology may include LTE D2D and V2X technologies and interfaces (such as Sidelink communications, etc.). Similarly, the 3GPP NR technology includes NR V2X technologies and interface (such as Sidelink communications, etc.). 
     The base station  114   a  in the RAN  103 / 104 / 105  and the WTRUs  102   a ,  102   b ,  102   c , and  102   g  or RRHs  118   a ,  118   b , TRPS  119   a ,  119   b  or RSUs  120   a ,  120   b  in the RAN  103   b / 104   b / 105   b  and the WTRUs  102   c ,  102   d ,  102   e ,  102   f  may implement radio technologies such as IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. 
     The base station  114   c  in  FIG.  14 A  may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a train, an aerial, a satellite, a manufactory, a campus, and the like, for implementing the methods, systems, and devices of RAN slicing, as disclosed herein. In an example, the base station  114   c  and the WTRUs  102 , e.g., WTRU  102   e , may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). similarly, the base station  114   c  and the WTRUs  102   d , may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another example, the base station  114   c  and the WTRUs  102 , e.g., WTRU  102   e , may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, NR, etc.) to establish a picocell or femtocell. As shown in  FIG.  14 A , the base station  114   c  may have a direct connection to the Internet  110 . Thus, the base station  114   c  may not be required to access the Internet  110  via the core network  106 / 107 / 109 . 
     The RAN  103 / 104 / 105  or RAN  103   b / 104   b / 105   b  may be in communication with the core network  106 / 107 / 109 , which may be any type of network configured to provide voice, data, messaging, authorization and authentication, applications, or voice over internet protocol (VoIP) services to one or more of the WTRUs  102   a ,  102   b ,  102   c ,  102   d . For example, the core network  106 / 107 / 109  may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, packet data network connectivity, Ethernet connectivity, video distribution, etc., or perform high-level security functions, such as user authentication. 
     Although not shown in  FIG.  14 A , it will be appreciated that the RAN  103 / 104 / 105  or RAN  103   b / 104   b / 105   b  or the core network  106 / 107 / 109  may be in direct or indirect communication with other RANs that employ the same RAT as the RAN  103 / 104 / 105  or RAN  103   b / 104   b / 105   b  or a different RAT. For example, in addition to being connected to the RAN  103 / 104 / 105  or RAN  103   b / 104   b / 105   b , which may be utilizing an E-UTRA radio technology, the core network  106 / 107 / 109  may also be in communication with another RAN (not shown) employing a GSM or NR radio technology. 
     The core network  106 / 107 / 109  may also serve as a gateway for the WTRUs  102   a ,  102   b ,  102   c ,  102   d ,  102   e  to access the PSTN  108 , the Internet  110 , or other networks  112 . The PSTN  108  may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet  110  may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and the internet protocol (IP) in the TCP/IP internet protocol suite. The networks  112  may include wired or wireless communications networks owned or operated by other service providers. For example, the networks  112  may include any type of packet data network (e.g., an IEEE 802.3 Ethernet network) or another core network connected to one or more RANs, which may employ the same RAT as the RAN  103 / 104 / 105  or RAN  103   b / 104   b / 105   b  or a different RAT. 
     Some or all of the WTRUs  102   a ,  102   b ,  102   c ,  102   d ,  102   e , and  102   f  in the communications system  100  may include multi-mode capabilities, e.g., the WTRUs  102   a ,  102   b ,  102   c ,  102   d ,  102   e , and  102   f  may include multiple transceivers for communicating with different wireless networks over different wireless links for implementing methods, systems, and devices of RAN slicing, as disclosed herein. For example, the WTRU  102   g  shown in  FIG.  14 A  may be configured to communicate with the base station  114   a , which may employ a cellular-based radio technology, and with the base station  114   c , which may employ an IEEE 802 radio technology. 
     Although not shown in  FIG.  14 A , it will be appreciated that a User Equipment may make a wired connection to a gateway. The gateway maybe a Residential Gateway (RG). The RG may provide connectivity to a Core Network  106 / 107 / 109 . It will be appreciated that much of the subject matter included herein may equally apply to UEs that are WTRUs and UEs that use a wired connection to connect with a network. For example, the subject matter that applies to the wireless interfaces  115 ,  116 ,  117  and  115   c / 116   c / 117   c  may equally apply to a wired connection. 
       FIG.  14 B  is a system diagram of an example RAN  103  and core network  106  that may implement methods, systems, and devices of RAN slicing, as disclosed herein. As noted herein, the RAN  103  may employ a UTRA radio technology to communicate with the WTRUs  102   a ,  102   b , and  102   c  over the air interface  115 . The RAN  103  may also be in communication with the core network  106 . As shown in  FIG.  14 B , the RAN  103  may include Node-Bs  140   a ,  140   b , and  140   c , which may each include one or more transceivers for communicating with the WTRUs  102   a ,  102   b , and  102   c  over the air interface  115 . The Node-Bs  140   a ,  140   b , and  140   c  may each be associated with a particular cell (not shown) within the RAN  103 . The RAN  103  may also include RNCs  142   a ,  142   b . It will be appreciated that the RAN  103  may include any number of Node-Bs and Radio Network Controllers (RNCs.) 
     As shown in  FIG.  14 B , the Node-Bs  140   a ,  140   b  may be in communication with the RNC  142   a . Additionally, the Node-B  140   c  may be in communication with the RNC  142   b . The Node-Bs  140   a ,  140   b , and  140   c  may communicate with the respective RNCs  142   a  and  142   b  via an Iub interface. The RNCs  142   a  and  142   b  may be in communication with one another via an Iur interface. Each of the RNCs  142   a  and  142   b  may be configured to control the respective Node-Bs  140   a ,  140   b , and  140   c  to which it is connected. In addition, each of the RNCs  142   a  and  142   b  may be configured to carry out or support other functionality, such as outer loop power control, load control, admission control, packet scheduling, handover control, macro-diversity, security functions, data encryption, and the like. 
     The core network  106  shown in  FIG.  14 B  may include a media gateway (MGW)  144 , a Mobile Switching Center (MSC)  146 , a Serving GPRS Support Node (SGSN) 148, or a Gateway GPRS Support Node (GGSN)  150 . While each of the foregoing elements are depicted as part of the core network  106 , it will be appreciated that any one of these elements may be owned or operated by an entity other than the core network operator. 
     The RNC  142   a  in the RAN  103  may be connected to the MSC  146  in the core network  106  via an IuCS interface. The MSC  146  may be connected to the MGW  144 . The MSC  146  and the MGW  144  may provide the WTRUs  102   a ,  102   b , and  102   c  with access to circuit-switched networks, such as the PSTN  108 , to facilitate communications between the WTRUs  102   a ,  102   b , and  102   c , and traditional land-line communications devices. 
     The RNC  142   a  in the RAN  103  may also be connected to the SGSN  148  in the core network  106  via an IuPS interface. The SGSN  148  may be connected to the GGSN  150 . The SGSN  148  and the GGSN  150  may provide the WTRUs  102   a ,  102   b , and  102   c  with access to packet-switched networks, such as the Internet  110 , to facilitate communications between and the WTRUs  102   a ,  102   b , and  102   c , and IP-enabled devices. 
     The core network  106  may also be connected to the other networks  112 , which may include other wired or wireless networks that are owned or operated by other service providers. 
       FIG.  14 C  is a system diagram of an example RAN  104  and core network  107  that may implement methods, systems, and devices of RAN slicing, as disclosed herein. As noted herein, the RAN  104  may employ an E-UTRA radio technology to communicate with the WTRUs  102   a ,  102   b , and  102   c  over the air interface  116 . The RAN  104  may also be in communication with the core network  107 . 
     The RAN  104  may include eNode-Bs  160   a ,  160   b , and  160   c , though it will be appreciated that the RAN  104  may include any number of eNode-Bs. The eNode-Bs  160   a ,  160   b , and  160   c  may each include one or more transceivers for communicating with the WTRUs  102   a ,  102   b , and  102   c  over the air interface  116 . For example, the eNode-Bs  160   a ,  160   b , and  160   c  may implement MIMO technology. Thus, the eNode-B  160   a , for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU  102   a.    
     Each of the eNode-Bs  160   a ,  160   b , and  160   c  may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink or downlink, and the like. As shown in  FIG.  14 C , the eNode-Bs  160   a ,  160   b , and  160   c  may communicate with one another over an X2 interface. 
     The core network  107  shown in  FIG.  14 C  may include a Mobility Management Gateway (MME)  162 , a serving gateway  164 , and a Packet Data Network (PDN) gateway  166 . While each of the foregoing elements are depicted as part of the core network  107 , it will be appreciated that any one of these elements may be owned or operated by an entity other than the core network operator. 
     The MME  162  may be connected to each of the eNode-Bs  160   a ,  160   b , and  160   c  in the RAN  104  via an S1 interface and may serve as a control node. For example, the MME  162  may be responsible for authenticating users of the WTRUs  102   a ,  102   b , and  102   c , bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs  102   a ,  102   b , and  102   c , and the like. The MME  162  may also provide a control plane function for switching between the RAN  104  and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA. 
     The serving gateway  164  may be connected to each of the eNode-Bs  160   a ,  160   b , and  160   c  in the RAN  104  via the S1 interface. The serving gateway  164  may generally route and forward user data packets to/from the WTRUs  102   a ,  102   b , and  102   c . The serving gateway  164  may also perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs  102   a ,  102   b , and  102   c , managing and storing contexts of the WTRUs  102   a ,  102   b , and  102   c , and the like. 
     The serving gateway  164  may also be connected to the PDN gateway  166 , which may provide the WTRUs  102   a ,  102   b , and  102   c  with access to packet-switched networks, such as the Internet  110 , to facilitate communications between the WTRUs  102   a ,  102   b ,  102   c , and IP-enabled devices. 
     The core network  107  may facilitate communications with other networks. For example, the core network  107  may provide the WTRUs  102   a ,  102   b , and  102   c  with access to circuit-switched networks, such as the PSTN  108 , to facilitate communications between the WTRUs  102   a ,  102   b , and  102   c  and traditional land-line communications devices. For example, the core network  107  may include, or may communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the core network  107  and the PSTN  108 . In addition, the core network  107  may provide the WTRUs  102   a ,  102   b , and  102   c  with access to the networks  112 , which may include other wired or wireless networks that are owned or operated by other service providers. 
       FIG.  14 D  is a system diagram of an example RAN  105  and core network  109  that may implement methods, systems, and devices of RAN slicing, as disclosed herein. The RAN  105  may employ an NR radio technology to communicate with the WTRUs  102   a  and  102   b  over the air interface  117 . The RAN  105  may also be in communication with the core network  109 . A Non-3GPP Interworking Function (N3IWF)  199  may employ a non-3GPP radio technology to communicate with the WTRU  102   c  over the air interface  198 . The N3IWF  199  may also be in communication with the core network  109 . 
     The RAN  105  may include gNode-Bs  180   a  and  180   b . It will be appreciated that the RAN  105  may include any number of gNode-Bs. The gNode-Bs  180   a  and  180   b  may each include one or more transceivers for communicating with the WTRUs  102   a  and  102   b  over the air interface  117 . When integrated access and backhaul connection are used, the same air interface may be used between the WTRUs and gNode-Bs, which may be the core network  109  via one or multiple gNBs. The gNode-Bs  180   a  and  180   b  may implement MIMO, MU-MIMO, or digital beamforming technology. Thus, the gNode-B  180   a , for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU  102   a . It should be appreciated that the RAN  105  may employ of other types of base stations such as an eNode-B. It will also be appreciated the RAN  105  may employ more than one type of base station. For example, the RAN may employ eNode-Bs and gNode-Bs. 
     The N3IWF  199  may include a non-3GPP Access Point  180   c . It will be appreciated that the N3IWF  199  may include any number of non-3GPP Access Points. The non-3GPP Access Point  180   c  may include one or more transceivers for communicating with the WTRUs  102   c  over the air interface  198 . The non-3GPP Access Point  180   c  may use the 802.11 protocol to communicate with the WTRU  102   c  over the air interface  198 . 
     Each of the gNode-Bs  180   a  and  180   b  may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink or downlink, and the like. As shown in  FIG.  14 D , the gNode-Bs  180   a  and  180   b  may communicate with one another over an Xn interface, for example. 
     The core network  109  shown in  FIG.  14 D  may be a 5G core network (5GC). The core network  109  may offer numerous communication services to customers who are interconnected by the radio access network. The core network  109  comprises a number of entities that perform the functionality of the core network. As used herein, the term “core network entity” or “network function” refers to any entity that performs one or more functionalities of a core network. It is understood that such core network entities may be logical entities that are implemented in the form of computer-executable instructions (software) stored in a memory of, and executing on a processor of, an apparatus configured for wireless or network communications or a computer system, such as system  90  illustrated in  FIG.  14 G . 
     In the example of  FIG.  14 D , the 5G Core Network  109  may include an access and mobility management function (AMF)  172 , a Session Management Function (SMF)  174 , User Plane Functions (UPFs)  176   a  and  176   b , a User Data Management Function (UDM)  197 , an Authentication Server Function (AUSF)  190 , a Network Exposure Function (NEF)  196 , a Policy Control Function (PCF)  184 , a Non-3GPP Interworking Function (N3IWF)  199 , a User Data Repository (UDR)  178 . While each of the foregoing elements are depicted as part of the 5G core network  109 , it will be appreciated that any one of these elements may be owned or operated by an entity other than the core network operator. It will also be appreciated that a 5G core network may not include all of these elements, may include additional elements, and may include multiple instances of each of these elements.  FIG.  14 D  shows that network functions directly connect with one another, however, it should be appreciated that they may communicate via routing agents such as a diameter routing agent or message buses. 
     In the example of  FIG.  14 D , connectivity between network functions is achieved via a set of interfaces, or reference points. It will be appreciated that network functions may be modeled, described, or implemented as a set of services that are invoked, or called, by other network functions or services. Invocation of a Network Function service may be achieved via a direct connection between network functions, an exchange of messaging on a message bus, calling a software function, etc. 
     The AMF  172  may be connected to the RAN  105  via an N2 interface and may serve as a control node. For example, the AMF  172  may be responsible for registration management, connection management, reachability management, access authentication, access authorization. The AMF may be responsible forwarding user plane tunnel configuration information to the RAN  105  via the N2 interface. The AMF  172  may receive the user plane tunnel configuration information from the SMF via an N11 interface. The AMF  172  may generally route and forward NAS packets to/from the WTRUs  102   a ,  102   b , and  102   c  via an N1 interface. The N1 interface is not shown in  FIG.  14 D . The SMF  174  may be connected to the AMF  172  via an N11 interface. 
     Similarly the SMF may be connected to the PCF  184  via an N7 interface, and to the UPFs  176   a  and  176   b  via an N4 interface. The SMF  174  may serve as a control node. For example, the SMF  174  may be responsible for Session Management, IP address allocation for the WTRUs  102   a ,  102   b , and  102   c , management and configuration of traffic steering rules in the UPF  176   a  and UPF  176   b , and generation of downlink data notifications to the AMF  172 . 
     The UPF  176   a  and UPF  176   b  may provide the WTRUs  102   a ,  102   b , and  102   c  with access to a Packet Data Network (PDN), such as the Internet  110 , to facilitate communications between the WTRUs  102   a ,  102   b , and  102   c  and other devices. The UPF  176   a  and UPF  176   b  may also provide the WTRUs  102   a ,  102   b , and  102   c  with access to other types of packet data networks. For example, Other Networks  112  may be Ethernet Networks or any type of network that exchanges packets of data. The UPF  176   a  and UPF  176   b  may receive traffic steering rules from the SMF  174  via the N4 interface. The UPF  176   a  and UPF  176   b  may provide access to a packet data network by connecting a packet data network with an N6 interface or by connecting to each other and to other UPFs via an N9 interface. In addition to providing access to packet data networks, the UPF  176  may be responsible packet routing and forwarding, policy rule enforcement, quality of service handling for user plane traffic, downlink packet buffering. 
     The AMF  172  may also be connected to the N3IWF  199 , for example, via an N2 interface. The N3IWF facilitates a connection between the WTRU  102   c  and the 5G core network  170 , for example, via radio interface technologies that are not defined by 3GPP. The AMF may interact with the N3IWF  199  in the same, or similar, manner that it interacts with the RAN  105 . 
     The PCF  184  may be connected to the SMF  174  via an N7 interface, connected to the AMF  172  via an N15 interface, and to an Application Function (AF)  188  via an N5 interface. The N15 and N5 interfaces are not shown in  FIG.  14 D . The PCF  184  may provide policy rules to control plane nodes such as the AMF  172  and SMF  174 , allowing the control plane nodes to enforce these rules. The PCF  184 , may send policies to the AMF  172  for the WTRUs  102   a ,  102   b , and  102   c  so that the AMF may deliver the policies to the WTRUs  102   a ,  102   b , and  102   c  via an N1 interface. Policies may then be enforced, or applied, at the WTRUs  102   a ,  102   b , and  102   c.    
     The UDR  178  may act as a repository for authentication credentials and subscription information. The UDR may connect with network functions, so that network function can add to, read from, and modify the data that is in the repository. For example, the UDR  178  may connect with the PCF  184  via an N36 interface. Similarly, the UDR  178  may connect with the NEF  196  via an N37 interface, and the UDR  178  may connect with the UDM  197  via an N35 interface. 
     The UDM  197  may serve as an interface between the UDR  178  and other network functions. The UDM  197  may authorize network functions to access of the UDR  178 . For example, the UDM  197  may connect with the AMF  172  via an N8 interface, the UDM  197  may connect with the SMF  174  via an N10 interface. Similarly, the UDM  197  may connect with the AUSF  190  via an N13 interface. The UDR  178  and UDM  197  may be tightly integrated. 
     The AUSF  190  performs authentication related operations and connect with the UDM  178  via an N13 interface and to the AMF  172  via an N12 interface. 
     The NEF  196  exposes capabilities and services in the 5G core network  109  to Application Functions (AF)  188 . Exposure may occur on the N33 API interface. The NEF may connect with an AF  188  via an N33 interface and it may connect with other network functions in order to expose the capabilities and services of the 5G core network  109 . 
     Application Functions  188  may interact with network functions in the 5G Core Network  109 . Interaction between the Application Functions  188  and network functions may be via a direct interface or may occur via the NEF  196 . The Application Functions  188  may be considered part of the 5G Core Network  109  or may be external to the 5G Core Network  109  and deployed by enterprises that have a business relationship with the mobile network operator. 
     Network Slicing is a mechanism that may be used by mobile network operators to support one or more ‘virtual’ core networks behind the operator&#39;s air interface. This involves ‘slicing’ the core network into one or more virtual networks to support different RANs or different service types running across a single RAN. Network slicing enables the operator to create networks customized to provide optimized solutions for different market scenarios which demands diverse requirements, e.g. in the areas of functionality, performance and isolation. 
     3GPP has designed the 5G core network to support Network Slicing. Network Slicing is a good tool that network operators can use to support the diverse set of 5G use cases (e.g., massive IoT, critical communications, V2X, and enhanced mobile broadband) which demand very diverse and sometimes extreme requirements. Without the use of network slicing techniques, it is likely that the network architecture would not be flexible and scalable enough to efficiently support a wider range of use cases need when each use case has its own specific set of performance, scalability, and availability requirements. Furthermore, introduction of new network services should be made more efficient. 
     Referring again to  FIG.  14 D , in a network slicing scenario, a WTRU  102   a ,  102   b , or  102   c  may connect with an AMF  172 , via an N1 interface. The AMF may be logically part of one or more slices. The AMF may coordinate the connection or communication of WTRU  102   a ,  102   b , or  102   c  with one or more UPF  176   a  and  176   b , SMF  174 , and other network functions. Each of the UPFs  176   a  and  176   b , SMF  174 , and other network functions may be part of the same slice or different slices. When they are part of different slices, they may be isolated from each other in the sense that they may utilize different computing resources, security credentials, etc. 
     The core network  109  may facilitate communications with other networks. For example, the core network  109  may include, or may communicate with, an IP gateway, such as an IP Multimedia Subsystem (IMS) server, that serves as an interface between the 5G core network  109  and a PSTN  108 . For example, the core network  109  may include, or communicate with a short message service (SMS) service center that facilities communication via the short message service. For example, the 5G core network  109  may facilitate the exchange of non-IP data packets between the WTRUs  102   a ,  102   b , and  102   c  and servers or applications functions  188 . In addition, the core network  170  may provide the WTRUs  102   a ,  102   b , and  102   c  with access to the networks  112 , which may include other wired or wireless networks that are owned or operated by other service providers. 
     The core network entities described herein and illustrated in  FIG.  14 A ,  FIG.  14 C ,  FIG.  14 D , or  FIG.  14 E  are identified by the names given to those entities in certain existing 3GPP specifications, but it is understood that in the future those entities and functionalities may be identified by other names and certain entities or functions may be combined in future specifications published by 3GPP, including future 3GPP NR specifications. Thus, the particular network entities and functionalities described and illustrated in  FIG.  14 A ,  FIG.  14 B ,  FIG.  14 C ,  FIG.  14 D , or  FIG.  14 E  are provided by way of example only, and it is understood that the subject matter disclosed and claimed herein may be embodied or implemented in any similar communication system, whether presently defined or defined in the future. 
       FIG.  14 E  illustrates an example communications system  111  in which the systems, methods, apparatuses that implement RAN slicing, described herein, may be used. Communications system  111  may include Wireless Transmit/Receive Units (WTRUs) A, B, C, D, E, F, a base station gNB  121 , a V2X server  124 , and Road Side Units (RSUs)  123   a  and  123   b . In practice, the concepts presented herein may be applied to any number of WTRUs, base station gNBs, V2X networks, or other network elements. One or several or all WTRUs A, B, C, D, E, and F may be out of range of the access network coverage  131 . WTRUs A, B, and C form a V2X group, among which WTRU A is the group lead and WTRUs B and C are group members. 
     WTRUs A, B, C, D, E, and F may communicate with each other over a Uu interface  129  via the gNB  121  if they are within the access network coverage  131 . In the example of  FIG.  14 E , WTRUs B and F are shown within access network coverage  131 . WTRUs A, B, C, D, E, and F may communicate with each other directly via a Sidelink interface (e.g., PC5 or NR PC5) such as interface  125   a ,  125   b , or  128 , whether they are under the access network coverage  131  or out of the access network coverage  131 . For instance, in the example of  FIG.  14 E , WRTU D, which is outside of the access network coverage  131 , communicates with WTRU F, which is inside the coverage  131 . 
     WTRUs A, B, C, D, E, and F may communicate with RSU  123   a  or  123   b  via a Vehicle-to-Network (V2N)  133  or Sidelink interface  125   b . WTRUs A, B, C, D, E, and F may communicate to a V2X Server  124  via a Vehicle-to-Infrastructure (V2I) interface  127 . WTRUs A, B, C, D, E, and F may communicate to another UE  201  via a Vehicle-to-Person (V2P) interface  128 . 
       FIG.  14 F  is a block diagram of an example apparatus or device WTRU  102  that may be configured for wireless communications and operations in accordance with the systems, methods, and apparatuses that implement RAN slicing, described herein, such as a WTRU  102  of  FIG.  14 A ,  FIG.  14 B ,  FIG.  14 C ,  FIG.  14 D , or  FIG.  14 E , or  FIG.  1   - FIG.  9    (e.g., UEs or Cells). As shown in  FIG.  14 F , the example WTRU  102  may include a processor  118 , a transceiver  120 , a transmit/receive element  122 , a speaker/microphone  124 , a keypad  126 , a display/touchpad/indicators  128 , non-removable memory  130 , removable memory  132 , a power source  134 , a global positioning system (GPS) chipset  136 , and other peripherals  138 . It will be appreciated that the WTRU  102  may include any sub-combination of the foregoing elements. Also, the base stations  114   a  and  114   b , or the nodes that base stations  114   a  and  114   b  may represent, such as but not limited to transceiver station (BTS), a Node-B, a site controller, an access point (AP), a home node-B, an evolved home node-B (eNodeB), a home evolved node-B (HeNB), a home evolved node-B gateway, a next generation node-B (gNode-B), and proxy nodes, among others, may include some or all of the elements depicted in  FIG.  14 F  and may be an exemplary implementation that performs the disclosed systems and methods for RAN slicing described herein. 
     The processor  118  may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor  118  may perform signal coding, data processing, power control, input/output processing, or any other functionality that enables the WTRU  102  to operate in a wireless environment. The processor  118  may be coupled to the transceiver  120 , which may be coupled to the transmit/receive element  122 . While  FIG.  14 F  depicts the processor  118  and the transceiver  120  as separate components, it will be appreciated that the processor  118  and the transceiver  120  may be integrated together in an electronic package or chip. 
     The transmit/receive element  122  of a UE  201  may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station  114   a  of  FIG.  14 A ) over the air interface  115 / 116 / 117  or another UE  201  over the air interface  115   d / 116   d / 117   d . For example, the transmit/receive element  122  may be an antenna configured to transmit or receive RF signals. The transmit/receive element  122  may be an emitter/detector configured to transmit or receive IR, UV, or visible light signals, for example. The transmit/receive element  122  may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit/receive element  122  may be configured to transmit or receive any combination of wireless or wired signals. 
     In addition, although the transmit/receive element  122  is depicted in  FIG.  14 F  as a single element, the WTRU  102  may include any number of transmit/receive elements  122 . More specifically, the WTRU  102  may employ MIMO technology. Thus, the WTRU  102  may include two or more transmit/receive elements  122  (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface  115 / 116 / 117 . 
     The transceiver  120  may be configured to modulate the signals that are to be transmitted by the transmit/receive element  122  and to demodulate the signals that are received by the transmit/receive element  122 . As noted herein, the WTRU  102  may have multi-mode capabilities. Thus, the transceiver  120  may include multiple transceivers for enabling the WTRU  102  to communicate via multiple RATs, for example NR and IEEE 802.11 or NR and E-UTRA, or to communicate with the same RAT via multiple beams to different RRHs, TRPs, RSUs, or nodes. 
     The processor  118  of the WTRU  102  may be coupled to, and may receive user input data from, the speaker/microphone  124 , the keypad  126 , or the display/touchpad/indicators  128  (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit. The processor  118  may also output user data to the speaker/microphone  124 , the keypad  126 , or the display/touchpad/indicators  128 . In addition, the processor  118  may access information from, and store data in, any type of suitable memory, such as the non-removable memory  130  or the removable memory  132 . The non-removable memory  130  may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory  132  may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. The processor  118  may access information from, and store data in, memory that is not physically located on the WTRU  102 , such as on a server that is hosted in the cloud or in an edge computing platform or in a home computer (not shown). The processor  118  may be configured to control lighting patterns, images, or colors on the display or indicators  128  in response to whether the setup of the systems in some of the examples described herein are successful or unsuccessful, or otherwise indicate a status of RAN slicing and associated components. The control lighting patterns, images, or colors on the display or indicators  128  may be reflective of the status of any of the method flows or components in the FIG.&#39;S illustrated or discussed herein (e.g.,  FIG.  1   - FIG.  9   , etc.). Disclosed herein are messages and procedures of RAN slicing. The messages and procedures may be extended to provide interface/API for users to request resources via an input source (e.g., speaker/microphone  124 , keypad  126 , or display/touchpad/indicators  128 ) and request, configure, or query RAN slicing related information, among other things that may be displayed on display  128 . 
     The processor  118  may receive power from the power source  134  and may be configured to distribute or control the power to the other components in the WTRU  102 . The power source  134  may be any suitable device for powering the WTRU  102 . For example, the power source  134  may include one or more dry cell batteries, solar cells, fuel cells, and the like. 
     The processor  118  may also be coupled to the GPS chipset  136 , which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU  102 . In addition to, or in lieu of, the information from the GPS chipset  136 , the WTRU  102  may receive location information over the air interface  115 / 116 / 117  from a base station (e.g., base stations  114   a ,  114   b ) or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU  102  may acquire location information by way of any suitable location-determination method. 
     The processor  118  may further be coupled to other peripherals  138 , which may include one or more software or hardware modules that provide additional features, functionality, or wired or wireless connectivity. For example, the peripherals  138  may include various sensors such as an accelerometer, biometrics (e.g., finger print) sensors, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port or other interconnect interfaces, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, and the like. 
     The WTRU  102  may be included in other apparatuses or devices, such as a sensor, consumer electronics, a wearable device such as a smart watch or smart clothing, a medical or eHealth device, a robot, industrial equipment, a drone, a vehicle such as a car, truck, train, or an airplane. The WTRU  102  may connect with other components, modules, or systems of such apparatuses or devices via one or more interconnect interfaces, such as an interconnect interface that may comprise one of the peripherals  138 . 
       FIG.  14 G  is a block diagram of an exemplary computing system  90  in which one or more apparatuses of the communications networks illustrated in  FIG.  14 A ,  FIG.  14 C ,  FIG.  14 D  and  FIG.  14 E  as well as RAN slicing, such as the systems and methods illustrated in  FIG.  1    through  FIG.  9    described and claimed herein may be embodied, such as certain nodes or functional entities in the RAN  103 / 104 / 105 , Core Network  106 / 107 / 109 , PSTN  108 , Internet  110 , Other Networks  112 , or Network Services  113 . Computing system  90  may comprise a computer or server and may be controlled primarily by computer readable instructions, which may be in the form of software, wherever, or by whatever means such software is stored or accessed. Such computer readable instructions may be executed within a processor  91 , to cause computing system  90  to do work. The processor  91  may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor  91  may perform signal coding, data processing, power control, input/output processing, or any other functionality that enables the computing system  90  to operate in a communications network. Coprocessor  81  is an optional processor, distinct from main processor  91 , that may perform additional functions or assist processor  91 . Processor  91  or coprocessor  81  may receive, generate, and process data related to the methods and apparatuses disclosed herein for RAN slicing, such as receiving certain messages. 
     In operation, processor  91  fetches, decodes, and executes instructions, and transfers information to and from other resources via the computing system&#39;s main data-transfer path, system bus  80 . Such a system bus connects the components in computing system  90  and defines the medium for data exchange. System bus  80  typically includes data lines for sending data, address lines for sending addresses, and control lines for sending interrupts and for operating the system bus. An example of such a system bus  80  is the PCI (Peripheral Component Interconnect) bus. 
     Memories coupled to system bus  80  include random access memory (RAM)  82  and read only memory (ROM)  93 . Such memories include circuitry that allows information to be stored and retrieved. ROMs  93  generally include stored data that cannot easily be modified. Data stored in RAM  82  may be read or changed by processor  91  or other hardware devices. Access to RAM  82  or ROM  93  may be controlled by memory controller  92 . Memory controller  92  may provide an address translation function that translates virtual addresses into physical addresses as instructions are executed. Memory controller  92  may also provide a memory protection function that isolates processes within the system and isolates system processes from user processes. Thus, a program running in a first mode may access only memory mapped by its own process virtual address space; it cannot access memory within another process&#39;s virtual address space unless memory sharing between the processes has been set up. 
     In addition, computing system  90  may include peripherals controller  83  responsible for communicating instructions from processor  91  to peripherals, such as printer  94 , keyboard  84 , mouse  95 , and disk drive  85 . 
     Display  86 , which is controlled by display controller  96 , is used to display visual output generated by computing system  90 . Such visual output may include text, graphics, animated graphics, and video. The visual output may be provided in the form of a graphical user interface (GUI). Display  86  may be implemented with a CRT-based video display, an LCD-based flat-panel display, gas plasma-based flat-panel display, or a touch-panel. Display controller  96  includes electronic components required to generate a video signal that is sent to display  86 . 
     Further, computing system  90  may include communication circuitry, such as for example a wireless or wired network adapter  97 , that may be used to connect computing system  90  to an external communications network or devices, such as the RAN  103 / 104 / 105 , Core Network  106 / 107 / 109 , PSTN  108 , Internet  110 , WTRUs  102 , or Other Networks  112  of  FIG.  14 A ,  FIG.  14 B ,  FIG.  14 C ,  FIG.  14 D , or  FIG.  14 E , to enable the computing system  90  to communicate with other nodes or functional entities of those networks. The communication circuitry, alone or in combination with the processor  91 , may be used to perform the transmitting and receiving steps of certain apparatuses, nodes, or functional entities described herein. 
     It is understood that any or all of the apparatuses, systems, methods and processes described herein may be embodied in the form of computer executable instructions (e.g., program code) stored on a computer-readable storage medium which instructions, when executed by a processor, such as processors  118  or  91 , cause the processor to perform or implement the systems, methods and processes described herein. Specifically, any of the steps, operations, or functions described herein may be implemented in the form of such computer executable instructions, executing on the processor of an apparatus or computing system configured for wireless or wired network communications. Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any non-transitory (e.g., tangible or physical) method or technology for storage of information, but such computer readable storage media do not include signals. Computer readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible or physical medium which may be used to store the desired information and which may be accessed by a computing system. 
     In describing preferred methods, systems, or apparatuses of the subject matter of the present disclosure—RAN slicing—as illustrated in the Figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected. 
     The various techniques described herein may be implemented in connection with hardware, firmware, software or, where appropriate, combinations thereof. Such hardware, firmware, and software may reside in apparatuses located at various nodes of a communication network. The apparatuses may operate singly or in combination with each other to effectuate the methods described herein. As used herein, the terms “apparatus,” “network apparatus,” “node,” “device,” “network node,” or the like may be used interchangeably. In addition, the use of the word “or” is generally used inclusively unless otherwise provided herein. 
     This written description uses examples for the disclosed subject matter, including the best mode, and also to enable any person skilled in the art to practice the disclosed subject matter, including making and using any devices or systems and performing any incorporated methods. The disclosed subject matter may include other examples that occur to those skilled in the art (e.g., skipping steps, combining steps, or adding steps between exemplary methods disclosed herein). 
     Methods, systems, and apparatuses, among other things, as described herein may include the steps of UE is camped on a cell in TA 2 ; the UE reselects a cell in TA 1 ; the UE performs a Mobility Registration Update procedure to inform the network that it has moved to a TA that supports a different set of RAN slices; an AMF invokes the SMF&#39;s UpdateSMContext service to inform the SMF that the UE is not able to transmit/receive data for PDU sessions associated with slices that are not available; and AMF sends a Registration Accept message to the UE and indicates to the UE that PDU Sessions that are associated with the S-NSSAI that is not available are suspended or terminated. The Registration Accept may also include a timer that indicates that the PDU Session should be considered terminated if the UE does not Re-Register with the network in a location where the S-NSSAI is allowed before the timer has expired. All combinations in this paragraph and the following paragraphs (including the removal or addition of steps) are contemplated in a manner that is consistent with the other portions of the detailed description 
     Methods, systems, and apparatuses, among other things, as described herein may include the steps of the UE reselects a cell in TA 2 ; the UE performs a Mobility Registration Update procedure to inform the network that it has moved to a TA that supports a different set of RAN slices; the AMF invokes the SMF&#39;s UpdateSMContext service to inform the SMF/UPF that the UE is able to transmit/receive data for PDU sessions associated with slices that are available; the AMF sends a Registration Accept message to the UE and indicates to the UE that PDU Sessions that are associated with the S-NSSAI that are no longer suspended; the UE commences with UL/DL data transmission and reception for PDU sessions associated with S-NSSAI y , where the DL data may include any data that was buffered by the SMF/UPF while the UE was in TA 1 . UL/DL data transmission and reception for PDU sessions associated with other S-NSSAIs supported in TA 2 . All combinations in this paragraph and below paragraphs (including the removal or addition of steps) are contemplated in a manner that is consistent with the other portions of the detailed description. 
     Methods, systems, and apparatuses, among other things, as described herein may include the steps of camping, by a user equipment (UE), on a cell in first tracking area or a first radio access network notification area; reselecting, by the user equipment, a cell in a second tracking area or a second radio access network notification area; performing a mobility registration update procedure or UE configuration update command, wherein the mobility registration update procedure or UE configuration update command indicates that the second tracking area or the second radio access network notification area supports a different set of radio access network (RAN) slices than the first tracking area; determining S-NSAAI status with reference to suspension based on a received message; and in response to the message, commencing with uplink data or downlink data transmission or reception for PDU sessions associated with the S-NSSAI. The second tracking area may not support S-NSSAI. The downlink data may include data that was buffered by a session management function or user plane function while the user equipment was in the second tracking area. All combinations in this paragraph and below paragraph (including the removal or addition of steps) are contemplated in a manner that is consistent with the other portions of the detailed description. 
     Methods, systems, and apparatuses, among other things, as described herein may include the steps of receiving, from a second apparatus, information including a network slice configuration, wherein the network slice configuration comprises network slice selection assistance information (NSSAI), single-NSSAI (S-NSSAI), slice/service type (SST), or slice differentiator (SD); and based on the network slice configuration, performing, by a first apparatus, the following: cell selection; cell reselection; slice area registration update; radio resource control (RRC) connection establishment; RRC resume; public land mobile network (PLMN) selection; access control; random access; or paging reception. The NSSAI, the S-NSSAI, the SST, or the SD may be configured into the first apparatus as available or not available per cell, per physical cell identifier, per TA, per radio access network notification area, or per frequency. The cell selection or cell reselections may use slice priority (e.g., a preferred slice). The slice area registration update may be based on mobility registration update or RAN Notification Area (RNA) Update. The first apparatus may signal to the network to change slice registration area (e.g. TA, RNA) such that the network may provide dedicated configuration to the first apparatus as needed. For example, the dedicated configuration is associated with the configuration provided to a UE via dedicated signaling as the UE transitions into RRC_CONNECTED state. See  FIG.  4    and  FIG.  5    and associated description in which slice area registration update may be based on mobility registration update or RAN Notification Area (RNA) Update. Further, UE signal to the network change of slice registration area (e.g. TA, RNA) such that the network may provide dedicated configuration to the UE as needed. The network slice configuration may have been received in system information broadcast signaling, a paging message, or a non-access-stratum signaling message. The first apparatus may initially be in RRC_IDLE or RRC_INACTIVE state. The network slice configuration may initially be received when the first apparatus was in a RRC_CONNECTED state, in which it then subsequently transitioned into RRC_IDLE state or RRC_INACTIVE state; and based on the received network slice configuration while in the subsequently transitioned RRC_IDLE state and RRC_INACTIVE state, performing, by the first apparatus, the following: cell selection; cell reselection; slice area registration update; radio resource control (RRC) connection establishment; RRC resume; public land mobile network (PLMN) selection; access control; random access; or paging reception. the first apparatus may be a user equipment. The second apparatus may be a base station or a core network node such as AMF. All combinations in this paragraph and above paragraphs (including the removal or addition of steps) are contemplated in a manner that is consistent with the other portions of the detailed description.