CN114390613A

CN114390613A - Method for slice-based access barring and user equipment using the same

Info

Publication number: CN114390613A
Application number: CN202111208644.6A
Authority: CN
Inventors: 蔡慈真; 邱俊渊
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2020-10-19
Filing date: 2021-10-18
Publication date: 2022-04-22

Abstract

The present disclosure provides a method and user equipment for slice-based access barring. The method comprises the following steps: acquiring unicast non-access stratum signaling through a non-access stratum, wherein the unicast non-access stratum signaling comprises access category definitions corresponding to network slices; obtaining broadcast system information through an access layer, wherein the broadcast system information includes a local access category definition corresponding to a network slice; delivering, by the access stratum, the local access category definition to the non-access stratum; initiating an access attempt through a non-access stratum; determining, by the non-access stratum, an access category of the access attempt based on the access category definition and the local access category definition; and performing, by the access stratum, an access barring check on the access attempt according to the access category.

Description

Method for slice-based access barring and user equipment using the same

Technical Field

The present disclosure provides a method for slice-based access barring and a User Equipment (UE) using the same.

Background

Network slicing is one of the key features of 5G communications. The 3GPP specification TR 38.832 provides a mechanism to enable a UE to quickly access to network slices supported by a cell. Mechanisms include, for example, slice-based cell reselection, slice-based Random Access Channel (RACH) configuration, or slice-based access barring under network control. Therefore, how to enhance those mechanisms is important to the field of communication technology.

Disclosure of Invention

The present disclosure provides a method for slice-based access barring and a UE using the same. The method may assist the UE in performing slice-based access barring in a more efficient manner.

A method for slice-based access barring is provided, the method being applicable to a user equipment comprising an access stratum and a non-access stratum. The method comprises the following steps: acquiring unicast non-access stratum signaling through a non-access stratum, wherein the unicast non-access stratum signaling comprises access category definitions corresponding to network slices; obtaining broadcast system information through an access layer, wherein the broadcast system information includes a local access category definition corresponding to a network slice; delivering, by the access stratum, the local access category definition to the non-access stratum; initiating an access attempt through a non-access stratum; determining, by the non-access stratum, an access category of the access attempt based on the access category definition and the local access category definition; and performing, by the access stratum, an access barring check on the access attempt according to the access category.

In an embodiment of the disclosure, the method further comprises: after acquiring the broadcast system information, acquiring second broadcast system information through an access stratum, wherein the second broadcast system information comprises a second local access category definition; delivering, by the access stratum, the second local access category definition to the non-access stratum; and updating, by the non-access stratum, the local access category definition to a second local access category definition.

In an embodiment of the disclosure, the method further comprises: after acquiring the broadcast system information, acquiring second broadcast system information through an access stratum, wherein the second broadcast system information does not include a local access category definition; notifying the non-access stratum through the access stratum that no local access category definition exists in the second broadcast system information; and discarding, by the non-access stratum layer, the local access category definition in response to no local access category definition in the second broadcast system information.

In an embodiment of the present disclosure, wherein the access stratum acquires the broadcast system information from the first base station, and the access stratum acquires the second broadcast system information from the second base station after performing handover from the first base station to the second base station.

In an embodiment of the present disclosure, the broadcast system information further includes barring control information corresponding to the local access category definition, wherein the access stratum performs an access barring check according to the barring control information.

In an embodiment of the present disclosure, wherein the local access category definition is associated with an operator defined access category.

A method for slice-based access barring is provided, the method being applicable to a user equipment comprising an access stratum and a non-access stratum. The method comprises the following steps: acquiring unicast non-access stratum signaling through a non-access stratum, wherein the unicast non-access stratum signaling comprises access category definitions corresponding to network slices; initiating an access attempt through a non-access stratum; determining, by the non-access stratum, an access category of the access attempt based on the access category definition and an additional access category of the access attempt; and performing, by the access stratum, an access barring check on the access attempt according to the access category.

In an embodiment of the disclosure, the method further comprises: acquiring, by the access stratum, broadcast system information, wherein the broadcast system information includes barring control information corresponding to a second additional access category; performing an access barring check according to the barring control information if the additional access category of the access attempt is equal to the second additional access category; and if the additional access category of the access attempt is not equal to the second additional access category, performing an access barring check according to the second barring control information corresponding to the access category of the access attempt.

In an embodiment of the present disclosure, wherein the unicast non-access stratum signaling comprises a mapping relationship between the additional access categories and the network slices.

A User Equipment (UE) for slice-based access barring is provided. The UE includes: a transceiver, a storage medium, and a processor. The storage medium includes an access stratum and a non-access stratum. A processor is coupled to the storage medium and the transceiver, wherein the processor is configured to: obtaining, by a non-access stratum via a transceiver, unicast non-access stratum signaling, wherein the unicast non-access stratum signaling includes an access category definition corresponding to a network slice; obtaining, by an access layer, broadcast system information via a transceiver, wherein the broadcast system information includes a local access category definition corresponding to a network slice; delivering, by the access stratum, the local access category definition to the non-access stratum; initiating an access attempt through a non-access stratum; determining, by the non-access stratum, an access category of the access attempt based on the access category definition and the local access category definition; and performing, by the access stratum via the transceiver, an access barring check on the access attempt according to the access category.

A User Equipment (UE) for slice-based access barring is provided. The UE includes a transceiver, a storage medium, and a processor. The storage medium includes an access stratum and a non-access stratum. A processor is coupled to the storage medium and the transceiver, wherein the processor is configured to: obtaining, by a non-access stratum via a transceiver, unicast non-access stratum signaling, wherein the unicast non-access stratum signaling includes an access category definition corresponding to a network slice; initiating an access attempt through a non-access stratum; determining, by the non-access stratum, an access category of the access attempt based on the access category definition and an additional access category of the access attempt; and performing, by the access stratum, an access barring check on the access attempt according to the access category.

Based on the foregoing, the present disclosure may provide a UE with multiple classes of access class definitions. The UE may decide the access category of the access attempt by selecting one of the access category definitions based on the reception of the signaling. Thus, even if the number of signaling between the network and the UE is minimized, the network can command the UE to stop accessing the congested network slice at any time by sending signaling to the UE.

In order that the foregoing may be more readily understood, several embodiments are described in detail below with the drawings attached.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated into and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.

Fig. 1 shows a signaling diagram for updating access class definitions.

Fig. 2 shows a signaling diagram for updating barring control information.

Fig. 3 shows a signaling diagram of a procedure for slice-based access barring according to an embodiment of the present disclosure.

Fig. 4 shows a schematic diagram of determining an access category of an access attempt according to an embodiment of the present disclosure.

Fig. 5 shows a schematic diagram of determining an access category of an access attempt according to another embodiment of the present disclosure.

Fig. 6 illustrates a schematic diagram of determining an access category of an access attempt according to another embodiment of the present disclosure.

Fig. 7 shows a schematic diagram of UE AS behavior for updating local access category definitions according to an embodiment of the present disclosure.

Fig. 8 shows a schematic diagram of UE AS behavior for updating local access category definitions according to another embodiment of the present disclosure.

Fig. 9 illustrates a signaling diagram for obtaining barring control information associated with an additional access class definition according to an embodiment of the present disclosure.

Fig. 10 shows a signaling diagram of a procedure for slice-based access barring according to an embodiment of the present disclosure.

Fig. 11 illustrates a flow chart of a method for determining which inhibit control information is to be applied in accordance with an embodiment of the present disclosure.

Fig. 12 shows a schematic diagram of access categories of access attempts according to an embodiment of the disclosure.

Fig. 13 shows a schematic diagram of access categories of access attempts according to another embodiment of the present disclosure.

Fig. 14 shows a flow diagram of a method for slice-based access barring according to an embodiment of the present disclosure.

Fig. 15 shows a flow diagram of a method for slice-based access barring according to another embodiment of the present disclosure.

Fig. 16 shows a schematic diagram of a UE according to an embodiment of the present disclosure.

Description of the reference numerals

11: a core network;

12: a wireless access network;

13：UE NAS；

14：gNB；

15：UE AS；

71. 72, 73, 82, 83: local access category definition;

100：UE；

110: a processor;

120: a storage medium;

121: an access layer;

122: a non-access stratum;

130: a transceiver;

s31, S32, S33, S34, S35, S91, S92, S93, S94, S101, S102, S103, S104, S105, S111, S112, S113, S114, S115, S116, S117, S141, S142, S143, S144, S145, S146, S151, S152, S153, S154: a step of;

t1, t2, t 3: a time period;

t390: a timer.

Detailed Description

The network slice may be uniquely identified by a single network slice selection assistance information (S-NSSAI). The S-NSSAI may include a slice/service type (SST) field that identifies a type of a network slice by 8-bit data. The S-NSSAI may further include an optional Slice Differentiator (SD) field composed of 24-bit data. In some cases, the SST fields of different network slices may be the same, and the SD fields of different network slices may be different. For example, a network operator may deploy multiple network slices delivering the same features for different groups of UEs by configuring the multiple network slices with the same SST field but different SD fields.

The network may perform access control on the UE intended to access the network slice in order to restrict access attempts from the UE by using Unified Access Control (UAC) functionality as specified in 3GPP specifications TS 22.261, TS24.501, or TS 38.300. A network operator may define a plurality of operator-defined access categories that may be used to implement differentiated handling of different network slices. The network may broadcast barring control information (i.e., a series of barring parameters associated with operator defined access categories) in order to minimize the impact of congested network slices.

Under high network load conditions, the network may protect itself from overload by performing unified access control according to the unified access control functionality. Such unified access control may be initiated by the network when, for example, an access and mobility management (AMF) function requests to limit the load of UEs accessing the network by sending an overload start message containing the conditions defined in clause 5.19.5.2 of the 3GPP specification TS 23.501. For another example, the network may initiate unified access control if operation, administration, and maintenance (OAM) functionality requires. For other examples, the network may trigger itself to initiate unified access control.

The unified access control framework may be applicable to all UE states defined in the 5G New Radio (NR), such as the "RRC _ IDLE" state, the "RRC _ INACTIVE" state, or the "RRC _ CONNECTED" state. The network may broadcast barring control information associated with one or more access categories. When an access attempt is generated by the application layer of the UE, the UE may determine whether the access category of the access attempt matches an operator-defined access category (or standardized access category). In particular, the UE may store a mapping table of access categories. Table 1 is an example of a mapping table similar to table 4.5.2.2 of 3GPP specification TS 24.501. If the access attempt matches a rule in the mapping table, the UE may determine the access category of the access attempt according to the rule. On the other hand, if the access attempt matches the plurality of rules in the mapping table, the UE may determine the access category of the access attempt according to the lowest rule number of the plurality of rules.

TABLE 1

If the access attempt meets the requirements of multiple operator-defined access category definitions, the UE may decide on the access attempt according to the operator-defined access category definition having the lowest priority value. The operator defined access category definition may consist of parameters such as: a priority value, an operator defined access category number, a criterion consisting of one or more access category criterion types and associated access category criterion type values, or a standardized access category. Each operator-defined access category definition may have a different priority value. Different operator-defined access category definitions may have the same operator-defined access category number. The access category criteria type may include a Data Network Name (DNN), a 5G quality of service identifier (5G quality of service identifier; 5QI), an operating system identifier (OSId) that triggered the access attempt, an operating system specific application identifier (OSAppId) that triggered the access attempt, or an S-NSSAI. The standardized access category may be used in combination with the access identity of the UE to determine a Radio Resource Control (RRC) establishment cause.

One or more operator-defined access category definitions may be signaled to the UE via unicast non-access stratum (NAS) signaling. NAS signaling may be received by the NAS of the UE, where the NAS signaling may be a "registration accept message. The UE may obtain one or more operator-defined access category definitions from an operator-defined access category definition Information Element (IE) included in the NAS signaling. After receiving NAS signaling by the UE, the UE may feed back a response message to the AMF in order to confirm receipt of the one or more operator-defined access category definitions, where the response message may be a "registration complete message. In one embodiment, NAS signaling (or access category definition) may include a mapping relationship between network slices and access categories.

On the other hand, if the UE obtains an operator-defined access category definition information element from a "configuration update command message" received by the UE, and the operator-defined access category definition information includes one or more operator-defined access category definitions, the UE will replace any operator-defined access category definitions stored for a Registered Public Land Mobile Network (RPLMN) with the received operator-defined access category definitions. It should be noted that the maximum number of operator-defined access category definitions stored in the UE depends on the UE implementation.

After deciding the access category of the access attempt, the UE may perform an access barring check on the network slice according to the access category and a uniform access control barring parameter (i.e., barring control information) corresponding to the access category, where the uniform access control barring parameter may include "uac-barringInfoSetIndex", "uac-BarringFactor", "uac-BarringTime", or "uac-barringforessidentity". The parameter "uac-BarringFactor" may represent the likelihood that an access attempt will be allowed during an access barring check. The parameter "uac-BarringTime" may represent a minimum time in seconds before a new access attempt is to be performed after an access attempt is barred at the access barring check, where the access attempt and the new access attempt correspond to the same access category. The parameter "uac-BarringForAccessIdentity" may indicate whether an access attempt corresponding to a particular access identity is allowed. Table 2 is an example of the parameter "uac-BarringForaccessIdentity". For example, if "bit 0" of the bitmap received by the UE is equal to "0", the UE may decide to allow an access attempt corresponding to "access identity 1". If "bit 1" of the bitmap received by the UE is equal to "0", the UE may decide to allow an access attempt corresponding to "access identity 2".

TABLE 2

Bitmap	0	1	2	3	4	5	6
								Access identification	1	2	11	12	13	14	15

At least one mapping relationship among the access category and the unified access control barring parameter may be signaled to the UE via Access Stratum (AS) signaling (e.g., RRC signaling), such AS a System Information Block (SIB). Table 3 is an example of a mapping relationship. The UE may perform an access barring check according to the access category and the unified access control parameters, as depicted in the codes in table 4 (referring to 3GPP specification TS38.331, article 5.3.14.5).

TABLE 3

TABLE 4

To perform slice-based access barring, the UE will dynamically update the access class definition and barring control information. Fig. 1 shows a schematic diagram of updating access category definitions. The core network (or AMF)11 may transmit NAS signaling to the UE over a Radio Access Network (RAN) 12, where the NAS signaling may be a "UE configuration update command". The UE NAS (i.e., the UE's NAS)13 may receive NAS signaling and may update the access class definition based on the NAS signaling. The update procedure in fig. 1 may be used only when the UE has an established 5G mobility management (5 GMM) environment and the UE is in 5GMM connected mode. If the UE is in 5GMM-IDLE mode, the core network 11 may use a paging or notification procedure to initiate an update procedure for the UE.

Fig. 2 shows a signaling diagram for updating barring control information. When network slice congestion occurs, the core network 11 may transmit a message, such as an "overload start" message, to the gNB14 to indicate the congested network slice. The gNB14 may contain the relevant cells to the core network 11. That is, the core network 11 wants to restrict access attempts from the congested network slice of the gNB 14. After receiving the "overload start" message, the gNB14 may transmit an indication associated with the change in system information to the UE via a paging message or Downlink Control Information (DCI), where the indication may be carried by AS signaling. The UE may be a related UE (a received UE). That is, the UE may initiate an access attempt to the congested network slice. The UE AS (i.e., the access stratum or RRC layer of the UE) 15 may receive the indication and may perform a System Information (SI) acquisition procedure with the gNB14 according to the indication. The barring control information stored in the UE may be updated during a system information acquisition procedure. It should be noted that regardless of whether the UE is in the "RRC _ IDLE", "RRC _ INACTIVE", or "RRC _ CONNECTED" state, the UE needs to monitor the paging message (or DCI) in order to determine whether system information has changed. The UE AS15 may include an RRC layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, or a Physical (PHY) layer.

When network slice congestion occurs, the congested network slice should be mapped to unused operator-defined access classes or forbidden operator-defined access classes, and the network will inform the UE which network slice is congested. In some cases, the network may inform the UE of which network slice is congested by sending an S-NSSAI corresponding to the congested network slice to the UE via AS signaling. However, according to Table 1, the maximum number of operator-defined access categories may be equal to only 32 (i.e., the number of access categories: 32 to 63). Because the S-NSSAI may contain 32 bits of data, the maximum number of network slices defined by the S-NSSAI may be equal to 2^32, which is much larger than the maximum number of operator-defined access classes. That is, the S-NSSAI cannot be mapped onto the access categories in a one-to-one manner. Therefore, the network cannot indicate all network slices to the UE simply by using operator-defined access categories. On the other hand, the network may configure the UE to update the operator-defined access category definitions stored in the UE more frequently. The network may indicate a particular network slice to the UE by using one of the operator-defined access category definitions stored in the UE. However, frequently updating operator-defined access category definitions may increase signaling overhead.

Fig. 3 shows a signaling diagram of a procedure for slice-based access barring according to an embodiment of the present disclosure. In an embodiment, the UE may pre-store at least one stored access category definition corresponding to at least one network slice, wherein the stored access category definition may be configured by unicast NAS signaling. For example, the core network 11 may transmit NAS signaling to the UE, where the NAS signaling may include the stored access category definition. The UE may obtain the stored access category definition by acquiring NAS signaling via the UE NAS 13. The UE NAS13 may store the stored access category definitions.

In step S31, when network slice congestion occurs, the core network 11 may map the congested network slice to local access category definitions, which may correspond to operator-defined access categories, such as unused operator-defined access categories or forbidden operator-defined access categories. The core network 11 may transmit a message (e.g., an "overload start" message) to the gNB14 to indicate the congested network slice, where the message may include at least one local access category definition. The gNB14 may include several related cells to the core network 11. That is, the core network 11 wants to prevent the relevant cells belonging to the gNB14 from initiating access attempts corresponding to congested network slices.

After receiving the "overload start" message, the gNB14 may transmit broadcast system information associated with the change of the system information to the UE via a paging message or Downlink Control Information (DCI) in step S32. The broadcast system information may include a local access category definition and barring control information corresponding to the local access category definition. The UE may be a related UE. That is, the UE may initiate an access attempt to the congested network slice. The UE AS15 of the UE may acquire the broadcast system information transmitted from the gNB 14. In one embodiment, the broadcast system information may be carried by AS signaling, such AS a system information block (e.g., SIB1 or SIBx specified in the NR specification). Thus, interference to unrelated UEs caused by system information updates (e.g., paging messages) may be minimized.

In step S33, the UE AS15 may perform a system information acquisition procedure with the gNB14 according to the broadcast system information. In the system information acquisition procedure, the original barring control information stored in the UE may be updated based on the barring control information carried by the broadcast system information, and the local access category definition may be provided to the UE. The UE AS15 may obtain the local access category definition from the broadcast system information. Since the local access category definition or barring control information may be transmitted to the UE during the system information acquisition procedure, the core network 11 or the gNB14 may not need to transmit an additional configuration update command to the UE. Accordingly, signaling traffic (signaling traffic) corresponding to the UE may be reduced.

In step S34, the UE AS15 may deliver the local access category definition to the UE NAS 13. In step S35, the UE NAS13 may add (or store) a local access category definition. It should be noted that the local access category definition will not change the stored local access category definition already stored in the UE NAS 13.

When initiating an access attempt, the UE may decide on the access category of the access attempt according to the stored access category definition or the local access category definition. In particular, the UE NAS13 may initiate an access attempt corresponding to a network slice. The access attempt may be generated, for example, by an application layer of the UE. The US NAS13 may initiate an access attempt after receiving signaling from the application layer of the UE.

The UE NAS13 may decide the access category of the access attempt according to the stored access category definition or the local access category definition. If the local access category definition corresponding to the network slice is stored in the UE NAS13, the UE NAS13 may decide the access category of the access attempt according to the local access category definition. If no local access category definition is stored in the UE NAS13, the UE NAS13 may decide the access category of the access attempt according to the stored access category definition in the UE NAS 13. After deciding on the access category of the access attempt, the UE NAS13 may deliver the access category of the access attempt to the UE AS 15. The AS15 may perform an access barring check on the network slice according to the access category of the access attempt. The UE AS15 may perform an access barring check according to barring control information, wherein the barring control information corresponds to an access category of the access attempt.

Fig. 4 shows a schematic diagram of determining an access category of an access attempt according to an embodiment of the present disclosure. Assume that the UE NAS13 prestores the stored access category definitions associated with network slice "slice a" and network slice "slice B". During the time period t1, since the local access category definition corresponding to the network slice "slice a" is not stored in the UE NAS13, if an access attempt corresponding to the network slice "slice a" is initiated, the UE NAS13 may decide the access category of the access attempt according to the stored access category definition. For example, the UE NAS13 may determine the access category of the access attempt as access category "AC 32" according to the stored access category definition. Thus, during the time period t1, the UE AS15 may perform an access barring check on the network slice "slice a" according to the barring control information (e.g., priority value "P ═ 5") corresponding to the access category "AC 32".

The barring control information may comprise at least one mapping between access categories and barring control parameters, wherein the barring control parameters may comprise at least one of a barring factor (e.g., uac-BarringFactor), a barring time (e.g., uac-BarringTime), or an access identity (e.g., uac-barringforessability). For example, NAS signaling and barring control information may include a mapping relationship between network slice "slice a", access category "AC 32", and priority value "P ═ 5". Table 5 is an example of the contents of the barring control information and the local access category definition.

TABLE 5

In one embodiment, NAS signaling (or access class definition) may map the same access class to different network slices. For example, NAS signaling may include both a mapping between network slice "slice a" and access category "AC 32" and a mapping between network slice "slice B" and access category "AC 32".

Assume that network slice congestion occurs on network slice "slice a" after time period t 1. The core network 11 may transmit broadcast system information to the UE AS15 in order to inform the UE that the network slice "slice a" is congested. The UE AS15 may obtain broadcast system information and the UE NAS13 may obtain a local access category definition corresponding to network slice "slice a" from the broadcast system information. During the time period t2, because at least one local access category definition corresponding to network slice "slice a" is stored in the UE NAS13, if an access attempt corresponding to network slice "slice a" is initiated, the UE NAS13 may decide the access category of the access attempt according to the local access category definition. In other words, the access category of the access attempt may be updated by the UE NAS13 according to the local access category definition. For example, the UE NAS13 may determine the access category of the access attempt as the access category "AC 33" according to the local access category definition having the priority value "P ═ 3". Thus, the UE AS15 may perform an access barring check on the network slice "slice a" according to the access category "AC 33".

Assume that network slice congestion occurs on network slice "slice a" after time period t 2. The core network 11 may transmit broadcast system information to the UE AS15 in order to inform the UE that the network slice "slice a" is no longer congested, wherein the broadcast system information may not include the local access category definition corresponding to the network slice "slice a". The core network 11 may transmit broadcast system information, such AS an "overload stop" message, via AS signaling. The UE AS15 may acquire broadcast system information. Since the local access category definition corresponding to the network slice "slice a" is not included in the broadcast system information, the UE NAS13 may discard the local access category definition corresponding to the network slice "slice a". During time period t3, if an access attempt corresponding to network slice "slice a" is initiated, the UE NAS13 may decide the access category of the access attempt according to the stored access category definition. In other words, the access category of the access attempt may be updated by the UE NAS13 according to the stored access category definition. For example, the UE NAS13 may determine the access category of the access attempt as access category "AC 32" according to the stored access category definition having a priority value "P ═ 5". Thus, the UE AS15 may perform an access barring check on the network slice "slice a" according to the access category "AC 32".

Fig. 5 shows a schematic diagram of determining an access category of an access attempt according to another embodiment of the present disclosure. Assume that the UE NAS13 prestores the stored access category definitions associated with network slice "slice a" and network slice "slice B".

During time period t1, because the local access category definition corresponding to network slice "slice C" or the stored access category definition corresponding to network slice "slice C" is not stored in the UE NAS13, if an access attempt corresponding to network slice "slice C" is initiated, the UE NAS13 may decide the access category of the access attempt according to the default access category definition. For example, the UE NAS13 may determine the access category of the access attempt as access category "AC 7" according to a default access category definition. Thus, during the time period t1, the UE AS15 may perform an access barring check on the network slice "slice C" according to the barring control information of the access category "AC 7".

Assume that network slice congestion occurs on network slice "slice C" after time period t 1. The core network 11 may transmit broadcast system information to the UE AS15 in order to inform the UE that the network slice "slice C" is congested. The UE AS15 may obtain broadcast system information and the UE NAS13 may obtain a local access category definition corresponding to network slice "slice C" from the broadcast system information. More specifically, the UE AS15 may deliver the local access category definition to the UE NAS13 in response to receiving the broadcast system information. During the time period t2, since at least one local access category definition corresponding to the network slice "slice C" is stored in the UE NAS13, if an access attempt corresponding to the network slice "slice C" is initiated, the UE NAS13 may decide the access category of the access attempt according to the local access category definition. In other words, the access category of the access attempt may be updated by the UE NAS13 according to the local access category definition. For example, the UE NAS13 may determine the access category of the access attempt as the access category "AC 34" according to the local access category definition having the priority value "P ═ 4". Thus, the UE AS15 may perform an access barring check on the network slice "slice C" according to the access category "AC 34".

Assume that network slice congestion occurs on network slice "slice C" after time period t 2. The core network 11 may transmit broadcast system information to the UE AS15 in order to inform the UE that the network slice "slice C" is no longer congested, wherein the broadcast system information may not include the local access category definition corresponding to the network slice "slice C". The UE AS15 may acquire broadcast system information. Since the local access category definition corresponding to network slice "slice C" or the stored access category definition corresponding to network slice "slice C" is not stored in the UE NAS13, if an access attempt corresponding to network slice "slice C" is initiated during time period t3, the UE NAS13 may decide the access category of the access attempt according to the default access category definition. In other words, the access category of the access attempt may be updated by the UE NAS13 according to the default access category definition. For example, the UE NAS13 may determine the access category of the access attempt as access category "AC 7" according to a default access category definition. Thus, during the time period t3, the UE AS15 may perform an access barring check on the network slice "slice C" according to the barring control information of the access category "AC 7".

Fig. 6 illustrates a schematic diagram of determining an access category of an access attempt according to another embodiment of the present disclosure. It is assumed that cell 1 (or the first base station) transmits broadcast system information during time period t2 and time period t 3. If the UE is served by cell 1 during the time period t2, the UE performs handover to cell 2 (or a second base station) after the time period t 2. Accordingly, the UE AS15 may acquire the broadcast system information from the cell 1 during the time period t2 and acquire the broadcast system information from the cell 2 after performing handover to the cell 2 (e.g., during the time period t 3). Because cell 2 may transmit broadcast system information not related to local access category definitions during time period t3, UE AS15 may not receive any of the local access category definitions during time period t 3.

In particular, assume that UE NAS13 pre-stores the stored access category definitions associated with network slice "slice a" and network slice "slice B" and that the UE is served by cell 1 during time period t 1. Since cell 1 may not transmit the broadcast system information during time period t1, UE AS15 may not receive the broadcast system information during time period t 1. Therefore, the local access category definition will not be delivered to the UE NAS 13.

If network slice congestion occurs on network slice "slice C" after time period t1, core network 11 may transmit broadcast system information to UE AS15 to inform the UE that network slice "slice C" is congested. The UE AS15 may obtain broadcast system information from cell 1 and the UE NAS13 may obtain a local access category definition corresponding to network slice "slice C" from the broadcast system information. The UE NAS13 may store a local access category definition corresponding to network slice "slice C".

If the UE performs a handover procedure to cell 2 after time period t2, the UE AS15 may no longer acquire broadcast system information from cell 1 during time period t 3. UE AS15 may acquire broadcast system information from cell 2 during time period t 3. However, since cell 2 may transmit broadcast system information not related to local access category definition during time period t3, in this embodiment, UE AS15 may not obtain any local access category definition during time period t 3. Therefore, the local class definition will not be delivered to the UE NAS 13.

It is assumed that at least one local access category definition corresponding to a network slice is stored in the UE NAS 13. If the UE AS15 receives new broadcast system information, the UE NAS13 may update the local access class definition according to the new broadcast system information. In particular, if the new broadcast system information comprises at least one new local access category definition corresponding to the network slice, the UE NAS13 may replace the original local access category definition stored in the UE NAS13 with the new local access category definition. Thus, the UE NAS13 may update the access category of the access attempt (i.e. the access attempt corresponding to the network slice) according to the new local access category definition. In one embodiment, if no local access category definition corresponding to the network slice is included in the new broadcast system information, the UE AS15 may inform the UE NAS13 that no local access category definition is included in the new broadcast system information. Thus, the UE NAS13 may discard the local access category definition corresponding to the network slice in the UE NAS 13. Thus, the UE NAS13 may update the access category of the access attempt (i.e. the access attempt corresponding to the network slice) according to a stored access category definition in the UE NAS13 or according to a default access category definition. Further, the UE AS15 may inform the upper layers of the UE (e.g., UE NAS 13) to discard the local access category definitions stored in the upper layers.

Fig. 7 shows a schematic diagram of UE AS15 behavior for updating local access category definitions according to an embodiment of the present disclosure. The UE NAS13 may obtain at least one local access category definition from the UE AS 15. In one embodiment, the UE AS15 may store the local access category definition and receive broadcast system information from the gNB14, where the broadcast system information may be carried by, for example, an updated system information block. After receiving the broadcast system information carrying at least one new local access category definition, the UE AS15 may replace the local access category definition stored in the UE AS15 with the new local access category definition. After this, the UE AS15 may deliver the new local access category definition to the UE NAS 13. If no local access category definition is included in the broadcast system information, the UE AS15 may notify the upper layers of the UE (e.g., UE NAS 13) to discard all local access category definitions stored in the upper layers.

For example, UE AS15 may store local access category definitions 71 corresponding to network slice "slice a", network slice "slice B", and network slice "slice C". UE AS15 may receive an updated system information block carrying a local access category definition 72, where the local access category definition 72 may correspond to network slice "slice a", network slice "slice B", and network slice "slice C". After receiving the updated system information block, the UE AS15 may replace the local access category definition 71 with the local access category definition 72, and the UE AS15 may deliver the local access category definition 72 to the UE NAS 13.

For another example, UE AS15 may store local access category definitions 71 corresponding to network slice "slice a", network slice "slice B", and network slice "slice C". UE AS15 may receive a system information block carrying an update of local access category definition 73, where in local access category definition 73 may correspond to network slice "slice a" and network slice "slice C". After receiving the updated system information block, the UE AS15 may replace the local access category definition 71 with the local access category definition 73, and the UE AS15 may deliver the local access category definition 73 to the UE NAS 13.

For other examples, UE AS15 may store local access category definitions 71 corresponding to network slice "slice a", network slice "slice B", and network slice "slice C". UE AS15 may receive the updated system information block that does not carry the local access category definition. After receiving the updated system information block, the UE AS15 may discard the local access category definition 71, and the UE AS15 may inform the upper layers of the UE (e.g., the UE NAS 13) to discard all local access category definitions stored in the upper layers.

Fig. 8 shows a schematic diagram of UE AS behavior for updating local access category definitions according to another embodiment of the present disclosure. The UE NAS13 may obtain at least one local access category definition from the UE AS 15. In one embodiment, the UE AS15 may not store the local access category definition. UE AS15 may receive broadcast system information from the gNB14, where the broadcast system information may be carried by, for example, an updated system information block. After receiving the broadcast system information carrying at least one new local access category definition, the UE AS15 may deliver the new local access category definition directly to the UE NAS 13. If the local access category definition is not included in the broadcast system information, the UE AS15 may notify the upper layers of the UE (e.g., UE NAS 13) to discard all local access category definitions stored in the upper layers.

For example, the UE AS15 may not store any of the local access category definitions. UE AS15 may receive an updated system information block carrying a local access category definition 82, where the local access category definition 82 may correspond to network slice "slice a", network slice "slice B", and network slice "slice C". After receiving the updated system information block, the UE AS15 may deliver the local access category definition 82 directly to the UE NAS 13.

For another example, the UE AS15 may not store any of the local access category definitions. UE AS15 may receive an updated system information block carrying a local access category definition 83, where in the local access category definition 83 may correspond to network slice "slice a" and network slice "slice C". After receiving the updated system information block, the UE AS15 may deliver the local access category definition 83 directly to the UE NAS 13.

For other examples, UE AS15 may not store any of the local access category definitions. The UE AS15 may receive an updated system information block that does not carry a local access category definition. After receiving the updated system information block, the UE AS15 may inform the upper layers of the UE (e.g., UE NAS 13) to discard all local access category definitions stored in the upper layers.

Fig. 9 illustrates a signaling diagram for obtaining barring control information associated with an additional access class definition according to an embodiment of the present disclosure. In step S91, a static mapping relationship between at least one additional access category definition and at least one network slice may be preconfigured for the core network 11 and the UE NAS 13.

In one embodiment, the UE may pre-store at least one legacy access category definition corresponding to the at least one network slice, and the UE may pre-store at least one additional access category definition corresponding to the at least one network slice, wherein either the legacy access category definition or the additional access category definition may be configured by unicast NAS signaling.

In particular, the core network 11 may transmit NAS signaling to the UE NAS13, wherein the NAS signaling may include access category definition information to the UE NAS13, wherein the access category definition information may include at least one additional access category definition corresponding to at least one network slice. After receiving the NAS signaling, the UE NAS13 may acquire access category definition information from the NAS signaling. The UE NAS13 may obtain the additional access category definition from the access category definition information and store the additional access category definition.

In one embodiment, the UE NAS 14 may obtain and store at least one legacy access category definition corresponding to at least one network slice before step S91 or in step S91. For example, the access category definition information may further include at least one legacy access category definition corresponding to the at least one network slice. The legacy access class definition may be an access class definition defined by the 3GPP specification TS 24.501. The additional access category definition may be an access category definition defined by the 3GPP specification TS 24.501. The legacy access category definition or the additional access category definition may be one of operator defined access category definitions.

In step S92, when network slice congestion occurs, the core network 11 may transmit a message, such as an "overload start" message, to the gNB14 in order to indicate the congested network slice, where the message may include data related to barring control information for additional access class definitions corresponding to the congested network slice. The gNB14 may include several related cells to the core network 11. That is, the core network 11 wants to prevent the relevant cells belonging to the gNB14 from initiating access attempts corresponding to congested network slices.

The barring control information may comprise at least one mapping between access categories and barring control parameters, wherein the barring control parameters may comprise at least one of a barring factor (e.g., uac-BarringFactor), a barring time (e.g., uac-BarringTime), or an access identity (e.g., uac-barringforessability). In one embodiment, NAS signaling and barring control information may map the same access category to different network slices. For example, the barring control information may include both a mapping between network slice "slice a" and access category "AC 32" and a mapping between network slice "slice B" and access category "AC 32". Table 6 is an example of the contents of the barring control information defined for the extra access category.

TABLE 6

After receiving the "overload start," the gNB14 may transmit broadcast system information associated with the change of system information (i.e., change notification) to the UE via a paging message or DCI in step S93. The broadcast system information may include barring control information corresponding to additional access category definitions for congested network slices. The UE may be a related UE. That is, the UE may initiate an access attempt to the congested network slice. UE AS15 may acquire the broadcast system information sent from the gNB 14. In one embodiment, the broadcast system information may be carried by AS signaling, such AS a system information block (e.g., SIB1 or SIBx specified in the NR specification). Table 7 is an example of SIB1 defined by 3GPP specification TS 38.331.

TABLE 7

In step S94, the UE AS15 may perform a system information acquisition procedure with the gNB14 according to the broadcast system information. In the system information acquisition procedure, barring control information for the additional access category definition may be provided to the UE AS 15. When initiating an access attempt, the UE may decide on the access category of the access attempt according to the stored access category definition or the additional access category definition. In particular, the UE NAS13 may initiate an access attempt corresponding to a network slice. The US NAS13 may initiate an access attempt after receiving signaling from the application layer of the UE.

Fig. 10 shows a signaling diagram of a procedure for slice-based access barring according to an embodiment of the present disclosure. Assume that an access attempt is initiated corresponding to a congested network slice. After the UE NAS13 initiates the access attempt, the UE NAS13 may deliver the access attempt to the UE AS15 in step S101. In one embodiment, the UE NAS13 may deliver a legacy access category (i.e., an access category defined by a legacy access category definition) or an additional access category (i.e., an access category defined by an additional access category definition) to the UE AS15 along with the access attempt, where the legacy access category or the additional access category is associated with the network slice.

In step S102, the UE AS15 may determine which barring control information is to be applied. In one embodiment, if the UE AS15 has received the barring control information for the extra access category definition (e.g., in step S94), the UE AS15 may decide to perform an access barring check on the access attempt according to the barring control information for the extra access category. If the UE AS15 has not received barring control information for the additional access category definition, the UE AS15 may decide to perform an access barring check on the access attempt according to the barring control information for the legacy access category.

Assume that UE AS15 has obtained barring control information and that the UE stores legacy access class definitions corresponding to congested network slices and stores additional access class definitions corresponding to congested network slices. In one embodiment, if the legacy access class definition corresponding to the congested network slice does not match the default access class definition, the UE AS15 may decide which barring control information is to be applied. If the legacy access class definition corresponding to the congested network slice matches the default access class definition, the UE AS15 may decide to perform an access barring check on the access attempt according to the barring control information of the legacy access class. For emergency situations, the default access category definition may correspond to an access category, such as "access category 0" or "access category 2" as defined in 3GPP specification TS 24.501.

After deciding the barring control information to apply to the access attempt, the UE AS15 may perform an access barring check on the network slice according to the access category in step S103. If the barring control information applied to the access attempt is decided based on the legacy access category, the UE AS15 may perform an access barring check according to the barring control information of the legacy access category. If the barring control information applied to the access attempt is decided based on the extra access category definition, the UE AS15 may perform an access barring check according to the barring control information of the extra access category. For example, the barring control information may include a barring time. UE AS15 may perform an access barring check according to timer T390 corresponding to the barring time.

If the result of the access barring check shows that the access attempt to the network slice is allowed, then in step S104 the UE AS15 may perform the access attempt by accessing the gNB 14. In step S105, after being accessed by the UE, the gNB14 may send an access attempt response corresponding to the access attempt to the UE AS 15.

Fig. 11 shows a flowchart of a method for determining which barring control information is to be applied, wherein the method may be implemented by a UE, according to an embodiment of the present disclosure. Assume that the UE stores at least one legacy access class definition corresponding to a network slice and stores at least one additional access class definition corresponding to the network slice.

If an access attempt corresponding to a network slice is initiated, the UE may check in step S111 whether the access attempt maps to a legacy access category corresponding to "access category 0", wherein "access category 0" is associated with a default access category definition. If the legacy access category corresponds to "access category 0", then proceed to step S112. If the legacy access class definition does not correspond to "access class 0", then proceed to step S113.

In step S112, the UE may perform a legacy behavior corresponding to "access category 0". "access category 0" means that access attempts are always through to the network slice.

In step S113, the UE may check whether the access attempt maps to a legacy access category corresponding to "access category 2", wherein "access category 2" is associated with a default access category definition. If the legacy access category corresponds to "access category 2", then proceed to step S114. If the legacy access category does not correspond to "access category 2", then proceed to step S115. It should be noted that since the priority of "access class 0" is higher than the priority of "access class 2", the UE first checks whether the access attempt belongs to "access class 0", and then the UE checks whether the access attempt belongs to "access class 2".

In step S114, barring control information corresponding to the legacy access category of "access category 2" is applied by the UE. The UE may perform an access barring check based on the barring control information of "access category 2".

In step S115, the UE may determine whether there is barring control information for the extra access category (i.e., stored by the UE). If there is barring control information for the additional access category, proceed to step S116. If there is no barring control information for the additional access category, then proceed to step S117.

In step S116, the barring control information defined by the extra access category is applied by the UE. The UE may perform an access barring check based on the barring control information for the additional access category.

In step S117, barring control information of the legacy access category is applied by the UE. The UE may perform an access barring check based on barring control information for the legacy access category (e.g., barring control information corresponding to the default access category definition).

Fig. 12 shows a schematic diagram of access categories of access attempts according to an embodiment of the disclosure. The US NAS13 may store a legacy access category definition of the access category "AC 7" and may store an additional access category definition of the access category "AC 1000". The US NAS13 may deliver the legacy access class "AC 7" to the UE AS15 and may deliver the additional access class "AC 1000" to the UE AS 15. The US AS15 may store a legacy access category "AC 7" and may store an additional access category "AC 1000", where the access category "AC 7" and the access category "AC 1000" are associated with access attempts corresponding to network slice "slice a". It is assumed that the UE does not receive the barring control information of the access category "AC 1000" before the end of the time period t 1. That is, there is no barring control information for the additional access category during the time period t 1. Assuming that an access attempt corresponding to network slice "slice a" is initiated during time period t1, UE AS15 may apply the barring control information for access category "AC 7" to the access attempt because there is no barring control information for the additional access category definition.

If network slice congestion occurs on network slice "slice a" after time period t1, the gNB14 may transmit barring control information for the access category "AC 1000" to the UE via broadcast system information, which may be carried by AS signaling. During time period t2, if there is barring control information for the additional access category, UE AS15 may apply the barring control information for the additional access category to the access attempt. Thus, UE AS15 may apply the barring control information of access category "AC 1000" to the access attempt.

Fig. 13 shows a schematic diagram of access categories of access attempts according to another embodiment of the present disclosure. The US NAS13 may store a legacy access category definition of the access category "AC 2" and may store an additional access category definition of the access category "AC 1000". The US NAS13 may deliver the legacy access class "AC 2" to the UE AS15 and may deliver the additional access class "AC 1000" to the UE AS 15. The US AS15 may store a legacy access category "AC 2" and may store an additional access category "AC 1000", where the access category "AC 2" and the access category "AC 1000" are associated with access attempts corresponding to network slice "slice a", and for emergency situations, the access category "AC 2" is associated with a default access category definition. It is assumed that the UE does not receive the barring control information of the access category "AC 1000" before the end of the time period t 1. That is, there is no barring control information for the additional access category during the time period t 1. Assuming that an access attempt corresponding to network slice "slice a" is initiated during time period t1, UE AS15 may apply the barring control information for access category "AC 2" to the access attempt because there is no barring control information for the additional access category.

If network slice congestion occurs on network slice "slice a" after time period t1, the gNB14 may transmit barring control information for the access category "AC 1000" to the UE via broadcast system information, which may be carried by AS signaling. During time period t2, in response to the access category "AC 2" matching the default access category definition, UE AS15 may apply barring control information for the access category "AC 2" to the access attempt even if there is barring control information for the additional access category definition.

Fig. 14 shows a flow diagram of a method for slice-based access barring according to an embodiment of the present disclosure, wherein the method is applicable to a UE comprising an access stratum and a non-access stratum. In step S141, unicast non-access stratum signaling is acquired by the non-access stratum, wherein the unicast non-access stratum signaling includes an access category definition corresponding to the network slice. In step S142, broadcast system information is acquired through the access stratum, wherein the broadcast system information includes a local access category definition corresponding to the network slice. In step S143, the local access category definition is delivered to the non-access stratum through the access stratum. In step S144, an access attempt is initiated through the non-access stratum. In step S145, the access category of the access attempt is decided by the non-access stratum according to the access category definition and the local access category definition. In step S146, an access barring check is performed on the access attempt by the access stratum according to the access category.

Fig. 15 shows a flowchart of a method for slice-based access barring according to another embodiment of the present disclosure, wherein the method is applicable to a UE comprising an access stratum and a non-access stratum. In step S151, unicast non-access stratum signaling is acquired by the non-access stratum, wherein the unicast non-access stratum signaling includes access category definitions corresponding to the network slice. In step S152, an access attempt is initiated through the non-access stratum. In step S153, the access category of the access attempt is decided by the non-access stratum according to the access category definition and the additional access category of the access attempt. In step S154, an access barring check is performed on the access attempt according to the access category by the access stratum.

Fig. 16 shows a schematic diagram of a UE 100 according to an embodiment of the present disclosure. UE 100 may include a processor 110, a storage medium 120, and a transceiver 130. The processor 110 is coupled to the storage medium 120 and the transceiver 130, and is configured to implement at least the method as described in fig. 1-16, as well as exemplary embodiments and alternative variations thereof.

The processor 110 may be implemented using programmable units such as microprocessors, microcontrollers, DSP chips, FPGAs, etc. The functions of the processor 110 may also be implemented using separate electronic devices or ICs. It should be noted that the functions of the processor 110 may be implemented in hardware or software.

The storage medium 120 may be, for example, any type of fixed or removable Random Access Memory (RAM), read-only memory (ROM), flash memory, Hard Disk Drive (HDD), Solid State Drive (SSD), or the like, or a combination thereof, configured to record a plurality of modules or various applications executable by the processor 110. In one embodiment, the storage medium 120 may store an access stratum 121 and a non-access stratum 122, where the above-mentioned UE AS15 and UE NAS13 may be implemented by the access stratum 121 and the non-access stratum 122, respectively.

Transceiver 130 may be configured to transmit and receive signals at radio frequencies or at millimeter wave frequencies, respectively. The transceiver 130 may also perform operations such as low noise amplification, impedance matching, frequency mixing, frequency up or down conversion, filtering, amplification, and so forth. Transceiver 130 may include one or more digital-to-analog (D/a) or analog-to-digital (D/a) converters configured to convert from an analog signal format to a digital signal format during uplink signal processing and from a digital signal format to an analog signal format during downlink signal processing. Transceiver 130 may include an antenna array, which may include one or more antennas that transmit and receive either omni-directional antenna beams or directional antenna beams.

Based on the above, the present disclosure may provide the stored access category definitions to the UE such that the UE may pre-store the stored access category definitions and the present disclosure may dynamically provide the local access category definitions to the UE. When network slice congestion occurs, the UE may decide the access category of the access attempt according to the local access category definition instead of the stored access category definition only if the UE receives broadcast system information corresponding to the local access category definition. Otherwise, the UE may decide the access category of the access attempt according to the stored access category definition, and the network may not have to send any signaling to the UE. In another aspect, the present disclosure may provide the UE with additional access category definitions. When network slice congestion occurs, the UE may decide the access category of the access attempt according to the extra access category definition instead of the legacy access category definition only when the UE receives barring control information corresponding to the extra access category definition. Otherwise, the UE may determine the access category of the access attempt according to the legacy access category definition. Thus, the network may command the UE to stop accessing the congested network slice at any time, even if the number of signaling between the network and the UE is minimized.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

1. A method for slice-based access barring, the method being applicable to a user equipment comprising an access stratum and a non-access stratum, the method comprising:

obtaining unicast non-access stratum signaling through the non-access stratum, wherein the unicast non-access stratum signaling comprises access category definitions corresponding to network slices;

obtaining, by the access stratum, broadcast system information, wherein the broadcast system information includes a local access category definition corresponding to the network slice;

delivering, by the access stratum layer, the local access category definition to the non-access stratum layer;

initiating an access attempt through the non-access stratum;

determining, by the non-access stratum, an access category of the access attempt from the access category definition and the local access category definition; and

performing, by the access layer, an access barring check on the access attempt according to the access category.

2. The method for slice-based access barring of claim 1, further comprising:

after acquiring the broadcast system information, acquiring second broadcast system information through the access stratum, wherein the second broadcast system information comprises a second local access category definition;

delivering, by the access stratum, the second local access category definition to the non-access stratum; and

updating, by the non-access stratum, the local access category definition to the second local access category definition.

3. The method for slice-based access barring of claim 1, further comprising:

after acquiring the broadcast system information, acquiring second broadcast system information through the access stratum, wherein the second broadcast system information does not include a local access category definition;

notifying, by the access stratum, the non-access stratum that there is no local access category definition in the second broadcast system information; and

discarding, by the non-access stratum layer, the local access category definition in response to no local access category definition in the second broadcast system information.

4. The method for slice-based access barring according to claim 2, wherein said access stratum acquires said broadcast system information from a first base station and said access stratum acquires said second broadcast system information from a second base station after performing a handover from said first base station to said second base station.

5. The method for slice-based access barring according to claim 1, wherein said broadcast system information further comprises barring control information corresponding to said local access category definition, wherein said access stratum performs said access barring check according to said barring control information.

6. The method for slice-based access barring according to claim 1, wherein said local access category definition is associated with an operator defined access category.

7. A method for slice-based access barring, the method being applicable to a user equipment comprising an access stratum and a non-access stratum, the method comprising:

initiating an access attempt through the non-access stratum;

determining, by the non-access stratum, an access category of the access attempt as a function of the access category definition and an additional access category of the access attempt; and

8. The method for slice-based access barring of claim 7, further comprising:

acquiring, by the access stratum, broadcast system information, wherein the broadcast system information includes barring control information corresponding to a second additional access category;

performing the access barring check according to the barring control information if the additional access category of the access attempt is equal to the second additional access category; and

performing the access barring check according to second barring control information corresponding to the access category of the access attempt if the additional access category of the access attempt is not equal to the second additional access category.

9. The method for slice-based access barring according to claim 7, wherein said unicast non-access stratum signaling comprises a mapping relationship between said additional access categories and said network slices.

10. A user equipment for slice-based access barring, comprising:

a transceiver;

a storage medium comprising an access stratum and a non-access stratum; and

a processor coupled to the storage medium and the transceiver, wherein the processor is configured to:

obtaining, by the non-access stratum via the transceiver, unicast non-access stratum signaling, wherein the unicast non-access stratum signaling comprises an access category definition corresponding to a network slice;

obtaining, by the access stratum via the transceiver, broadcast system information, wherein the broadcast system information includes a local access category definition corresponding to the network slice;

initiating an access attempt through the non-access stratum;

performing, by the access stratum via the transceiver, an access barring check on the access attempt according to the access category.

11. A user equipment for slice-based access barring, comprising:

a transceiver;

a storage medium comprising an access stratum and a non-access stratum; and

initiating an access attempt through the non-access stratum;