REGISTRATION TO A NETWORK SLICE SUBJECT TO ADMISSION CONTROL

Apparatuses, methods, and systems are disclosed for registering to a congested network slice. One method includes receiving a registration request from a communication device to register to a network slice subject to NSAC and determining that registration to the network slice is rejected for NSAC. The method includes initiating a timer in response to determining that the registration to the network slice is rejected and sending, to the communication device, an update message in response to expiry of the timer, the update message including an indication that the communication device is permitted to register to the network slice.

FIELD

The subject matter disclosed herein relates generally to wireless communications and more particularly relates to methods and apparatus for registration to a network slice subject to admission control.

BACKGROUND

One of the new features introduced in the Third Generation Partnership Project (“3GPP”) Fifth Generation (“5G”) communication system is the support of network slicing. With the evolution of the 5G system (“5GS”) and the network slicing feature, the network slice admission control was introduced. A network slice identified by Single Network Slice Selection Assistance Information (“S-NSSAI”) can be a subject to Network Slice Admission Control (“NSAC”). The 5GS may include a Network Slice Admission Control Function (“NSACF”) that monitors and controls the number of registered User Equipment (“UE”) devices per network slice for those network slices that are subject to NSAC.

BRIEF SUMMARY

Disclosed are procedures for registering to a congested network slice, i.e., a network slice subject to admission control. Said procedures may be implemented by apparatus, systems, methods, or computer program products.

One method at a network device includes receiving a registration request from a communication device to register to a network slice subject to NSAC and determining that registration to the network slice is rejected for NSAC. The first method includes initiating a timer in response to determining that the registration to the network slice is rejected and sending, to the communication device, an update message in response to expiry of the timer, the update message containing a first indication that the communication device is permitted to register to the network slice.

One method at a UE includes sending, by the communication device, a registration request to register to a network slice in a mobile communication network, the network slice subject to NSAC and receiving, from an access management function, a first response including an allowed set of network slices and a first indication that rejects registration to the network slice. The second method includes receiving, from the access management function, a second response including a second indication that the communication device is permitted to register to the network slice and establishing, by the communication device, a data connection using the network slice.

DETAILED DESCRIPTION

Generally, the present disclosure describes systems, methods, and apparatuses for registering to a congested network slice. In certain embodiments, the methods may be performed using computer code embedded on a computer-readable medium. In certain embodiments, an apparatus or system may include a computer-readable medium containing computer-readable code which, when executed by a processor, causes the apparatus or system to perform at least a portion of the below described solutions. A network slice customer can negotiate (or request) slice characteristics (or attributes) from the network operator (e.g., 5GS) deploying the network slice. The network slice characteristics may be identified by network slice attributes. Possible network slice attributes are described in the Groupe Speciale Mobile Association (“GSMA”) 5G Joint Activity (“5GJA”) working group in the document GSMA 5GJA NG.116 “Generic Network Slice Template”. The network operator uses the Generic Network Slice Template (“GST”) to derive the network slice characteristics.

One attribute in the GST is Maximum number of data connections (e.g., Protocol Data Unit (“PDU”) sessions or Packet Data Network (“PDN”) connections or Evolved Packet System (“EPS”) sessions). This attribute describes the maximum number of concurrent data connections supported by the network slice. In some embodiments, this attribute may include an optional parameter “EPS counting required” to indicate that PDN connections (also referred to as EPS sessions) are to be tracked. In one example, a network slice subject to NSAC may be limited to 100,000 concurrent data connections. In another example, the network slice subject to NSAC may be limited to 10,000,000 concurrent data connections. Table 1 depicts an example of the GST attribute for a Maximum number of PDU sessions.

Another attribute in the GST is Maximum number of communication devices (e.g., UEs). This attribute describes the maximum number of devices that can use the network slice simultaneously. In some embodiments, this attribute may include an optional parameter “EPS counting required” to indicate that UEs using PDN connections (also referred to as EPS sessions) that can be handed over to the 5GS (while the UEs are in the EPS) are to be tracked. In one example, a network slice subject to NSAC may be limited to 100,000 concurrent devices/users. In another example, the network slice subject to NSAC may be limited to 10,000,000 concurrent devices/users. Table 2 depicts an example of the GST attribute for a Maximum number of UEs.

As described above, the 5G network slicing feature enables network operators to optimize implementation of tailor-made functionality and network operation specific to the needs of a market scenario. The network slicing feature can be summarized as follows:

A network slice is a logical network that provides specific network capabilities and network characteristics. The network slice is identified by an S-NSSAI and may consist of a radio access network (“RAN”) part and a core network (“CN”) part. While the network can support large number of slices (e.g., hundreds), the UE need not support more than eight (8) slices simultaneously. Traffic for different slices is handled by different PDU sessions.

An S-NSSAI uniquely identifies a network slice and is comprised of a Slice/Service type (“SST”) and a Slice Differentiator (“SD”). The SST refers to the expected network slice behavior in terms of features and services. The SST field is of length 8 bits and may have standardized and non-standardized values: values 0 to 127 belong to the standardized SST range and are defined in 3GPP Technical Specification (“TS”) 23.501, and values 128 to 255 belong to the Operator-specific range.

The SD is optional information that complements the SST(s) to differentiate amongst multiple network slices of the same SST. For instance, for an SST of value eMBB, multiple SDs may be defined such as “Company X eMBB slice,” “Company Y eMBB slice” etc. The SD field is of length 24 bits. Optionally, the S-NSSAI may also include a mapped home Public Land Mobile Network (“HPLMN”) SST and/or mapped HPLMN SD.

The UE subscription data in the UDM/UDR stores a list of one or more Subscribed S-NSSAI(s), which a UE is subscribed to use in a Public Land Mobile Network (“PLMN”) (e.g., in a HPLMN or visited PLMN (“VPLMN”)).

A UE may be configured by the network with the following network slice configuration: Allowed Network Slice Selection Assistance Information (“NSSAI”) and Configured NSSAI. The Allowed NSSAI is a list of one or more S-NSSAIs provided by the serving PLMN during e.g. a Registration procedure, indicating the S-NSSAIs values the UE could use in the serving PLMN for the current Registration Area: derived by network from the Subscribed S-NSSAI and taking into account the S-NSSAIs which are valid for the current registration area and Access Type provided by the Access and Mobility Management Function (“AMF”) the UE has registered with: used by UE, e.g., to create IE “Requested NSSAI” in the Non-Access Stratum (“NAS”) registration request message and to establish PDU Sessions in the current registration area.

The configured NSSAI is a list of one or more S-NSSAIs applicable to one or more PLMNs and is derived by network from the Subscribed S-NSSAI. The configured NSSAI is used by UE if there are no allowed S-NSSAI(s) for the current PLMN (or Standalone Non-Public Network (“SNPN”)). The configured NSSAI contains only S-NSSAI values from the serving PLMN (i.e., which can be the HPLMN or a VPLMN). The configured NSSAI is obtained from the AMF upon successful completion of a UE's Registration procedure over an Access Type or as part of UE network slice configuration update procedure and is used by UE, e.g., to create the IE “Requested NSSAI” in the NAS registration request message. Note that the Requested NSSAI IE comprises a list of one or more S-NSSAIs to which the UE requests registration.

A network slice identified by S-NSSAI can be a subject to NSAC. The NSAC allows the use of the S-NSSAI resources up to a maximum number of registered UEs and/or a maximum number of established PDU Sessions in the S-NSSAI. If the maximum number of registered UEs and/or established PDU Sessions in the S-NSSAI are reached, then new UEs or PDU Sessions are rejected.

The NSACF monitors and controls the number of registered UEs per network slice for the network slices that are subject to NSAC. The NSACF and AMF are configured via the Operations, Administration and Maintenance (“OAM”) system that an S-NSSAI is subject to NSAC. The NSACF is configured with the maximum number of registered UEs and/or established PDU Sessions which are allowed to be served by the S-NSSAI that is subject to NSAC.

The NSACF controls (i.e., increase or decrease) the current number of UEs registered with a network slice so that the current number of UEs does not exceed the maximum number of UEs allowed to register with that network slice. The NSACF also maintains a list of one or more UE IDs registered with a network slice that is subject to NSAC. When the current number of UEs registered with a network slice is to be increased (i.e., when a UE attempts to register with the network slice), the NSACF first checks whether the UE Identity is already in the list of UEs registered with that network slice and if not, it checks whether the maximum number of UEs per network slice for that network slice has already been reached.

The AMF sends a request to NSACF when the UE registers with or deregisters from the S-NSSAI subject to NSAC, i.e., during the UE Registration procedure in clause 4.2.2.2.2 in 3GPP TS 23.502, UE Deregistration procedure in clause 4.2.2.3 in 3GPP TS 23.502, or UE Configuration Update procedure in clause 4.2.4.2 in 3GPP TS 23.502.

There can be a situation when a UE attempts to register with several S-NSSAIs however one or more S-NSSAIs may be subject to NSAC, and thus, congested due to the number of registered UEs exceeding the maximum number of UEs. As used herein, a “congested network slice” refers to any network slice (i.e., identified by S-NSSAI) subject to NSAC, where a limit (i.e., maximum number) is reached for a monitored network slice attribute/characteristic, such that access to the network slice is restricted. While the below descriptions discuss network slice congestion primarily in terms of the attribute “maximum number of UEs per network slice”, this is an exemplary attribute and the below solutions also apply to other monitored network slice attributes/characteristics where access restrictions are implemented once the monitored attribute/characteristics reaches a configured maximum value. The monitored network slice attribute of a network slice subject to NSAC may also be referred to as a “NSAC attribute” or “NSAC parameter.” Release 17 of 3GPP TS 24.501 has specified a mechanism where the network will inform the UE that those one or more S-NSSAIs are rejected and optionally also including a timer. The UE attempts to access to the one or more congested S-NSSAIs after the timer is expired by registration or without registration.

In order for the network to realize whether the UE support this mechanism, a new 5GMM capability IE which is called ER-NSSAI is defined. The UE uses this 5GMM capability IE to indicate to the network whether the UE supports the ER-NSSAI which includes a back off timer for the S-NSSAI which rejected for the maximum number of UEs reached. Once the back-off timer is expired the UE may attempt to register with the currently congested one or more S-NSSAIs.

The problem is that it is unclear whether and how the network (e.g., the AMF) rejects the S-NSSAI subject to NSAC towards UEs which does not support the NSAC feature (e.g., the ER-NSSAI). If the UE does not support the ER-NSSAI, such as that the UE has not implemented it or the UE is a pre-release 17 UE, then the network may need to communicate with the UE if the UE has attempted to register with one or more S-NSSAIs but failed due to congestion (i.e., exhaustion) for those one or more S-NSSAIs. Moreover, it is not clear how the network estimates the back-off timer to indicate to the UE when the one or more congested S-NSSAIs will be accessible.

Disclosed are solutions that a network may use to indicate to a UE with no capability for extended rejected S-NSSAI to attempt registering to the one or more S-NSSAIs which the UE was denied for due to the congestion. The solutions may be implemented by apparatus, systems, methods, or computer program products.

FIG.1depicts a wireless communication system100for registering to a congested network slice, according to embodiments of the disclosure. In one embodiment, the wireless communication system100includes at least one remote unit105, a RAN120, and a mobile CN140. The RAN120and the mobile CN140form a mobile communication network. The RAN120may be composed of a base unit121with which the remote unit105communicates using wireless communication links123. Even though a specific number of remote units105, base units121, wireless communication links123, RANs120, and mobile CNs140are depicted inFIG.1, one of skill in the art will recognize that any number of remote units105, base units121, wireless communication links123, RANs120, and mobile CNs140may be included in the wireless communication system100.

In one implementation, the RAN120is compliant with the 5G cellular system specified in the 3GPP specifications. For example, the RAN120may be a Next Generation Radio Access Network (“NG-RAN”), implementing NR Radio Access Technology (“RAT”) and/or Long-Term Evolution (“LTE”) RAT. In another example, the RAN120may include non-3GPP RAT (e.g., Wi-Fi® or Institute of Electrical and Electronics Engineers (“IEEE”) 802.11-family compliant WLAN). In another implementation, the RAN120is compliant with the LTE system specified in the 3GPP specifications. More generally, however, the wireless communication system100may implement some other open or proprietary communication network, for example Worldwide Interoperability for Microwave Access (“WiMAX”) or IEEE 802.16-family standards, among other networks. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

The remote units105may communicate directly with one or more of the base units121in the RAN120via uplink (“UL”) and downlink (“DL”) communication signals. Furthermore, the UL and DL communication signals may be carried over the wireless communication links123. Furthermore, the UL communication signals may comprise one or more UL channels, such as the Physical Uplink Control Channel (“PUCCH”) and/or Physical Uplink Shared Channel (“PUSCH”), while the DL communication signals may comprise one or more DL channels, such as the Physical Downlink Control Channel (“PDCCH”) and/or Physical Downlink Shared Channel (“PDSCH”). Here, the RAN120is an intermediate network that provides the remote units105with access to the mobile CN140.

In various embodiments, the remote units105may communicate directly with each other (e.g., device-to-device communication) using one or more sidelink communication links113. Here, sidelink transmissions may occur on sidelink resources. A remote unit105may be provided with different sidelink communication resources according to different allocation modes. As used herein, a “resource pool” refers to a set of resources assigned for sidelink operation. A resource pool consists of a set of resource blocks (i.e., Physical Resource Blocks (“PRB”)) over one or more time units (e.g., subframe, slots, Orthogonal Frequency Division Multiplexing (“OFDM”) symbols). In some embodiments, the set of resource blocks comprises contiguous PRBs in the frequency domain. A PRB, as used herein, consists of twelve consecutive subcarriers in the frequency domain.

In some embodiments, the remote units105communicate with an application server151via a network connection with the mobile CN140. For example, an application107(e.g., web browser, media client, telephone and/or Voice-over-Internet-Protocol (“VoIP”) application) in a remote unit105may trigger the remote unit105to establish a PDU session (or PDN connection) with the mobile CN140via the RAN120. The PDU session represents a logical connection between the remote unit105and the User Plane Function (“UPF”)141. The mobile CN140then relays traffic between the remote unit105and the application server151in the DN150using the PDU session (or other data connection).

In order to establish the PDU session (or PDN connection), the remote unit105must be registered with the mobile CN140(also referred to as “attached to the mobile core network” in the context of a Fourth Generation (“4G”) system). Note that the remote unit105may establish one or more PDU sessions (or other data connections) with the mobile CN140. As such, the remote unit105may have at least one PDU session for communicating with the DN150. The remote unit105may establish additional PDU sessions for communicating with other data networks and/or other communication peers.

In the context of a 5GS, the term “PDU Session” refers to a data connection that provides end-to-end (“E2E”) user plane (“UP”) connectivity between the remote unit105and a specific Data Network (“DN”) through the UPF141. A PDU Session supports one or more Quality of Service (“QoS”) Flows. In certain embodiments, there may be a one-to-one mapping between a QoS Flow and a QoS profile, such that all packets belonging to a specific QoS Flow have the same 5G QOS Identifier (“5QI”).

In the context of a 4G/LTE system, such as the EPS, a PDN connection (also referred to as EPS session) provides E2E UP connectivity between the remote unit and a PDN. The PDN connectivity procedure establishes an EPS Bearer, i.e., a tunnel between the remote unit105and a PDN Gateway (“PGW”, not shown) in the mobile CN140. In certain embodiments, there is a one-to-one mapping between an EPS Bearer and a QoS profile, such that all packets belonging to a specific EPS Bearer have the same QoS Class Identifier (“QCI”).

The base units121may be distributed over a geographic region. In certain embodiments, a base unit121may also be referred to as an access terminal, an access point, a base, a base station, a Node-B (“NB”), an Evolved Node B (abbreviated as eNodeB or “eNB,” also known as Evolved Universal Terrestrial Radio Access Network (“E-UTRAN”) Node B), a 5G/NR Node B (“gNB”), a Home Node-B, a relay node, a RAN node, or by any other terminology used in the art. The base units121are generally part of a RAN, such as the RAN120, that may include one or more controllers communicably coupled to one or more corresponding base units121. These and other elements of the RAN are not illustrated but are well known generally by those having ordinary skill in the art. The base units121connect to the mobile CN140via the RAN120.

The base units121may serve a number of remote units105within a serving area, for example, a cell or a cell sector, via a wireless communication link123. The base units121may communicate directly with one or more of the remote units105via communication signals. Generally, the base units121transmit DL communication signals to serve the remote units105in the time, frequency, and/or spatial domain. Furthermore, the DL communication signals may be carried over the wireless communication links123. The wireless communication links123may be any suitable carrier in licensed or unlicensed radio spectrum. The wireless communication links123facilitate communication between one or more of the remote units105and/or one or more of the base units121.

Note that during NR operation on unlicensed spectrum (referred to as “NR-U”), the base unit121and the remote unit105communicate over unlicensed (i.e., shared) radio spectrum. Similarly, during LTE operation on unlicensed spectrum (referred to as “LTE-U”), the base unit121and the remote unit105also communicate over unlicensed (i.e., shared) radio spectrum.

In one embodiment, the mobile CN140is a 5G Core network (“5GC”) or an Evolved Packet Core (“EPC”), which may be coupled to a DN150, like the Internet and private data networks, among other data networks. A remote unit105may have a subscription or other account with the mobile CN140. In various embodiments, each mobile CN140belongs to a single mobile network operator (“MNO”) and/or PLMN. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

The mobile CN140includes several network functions (“NFs”). As depicted, the mobile CN140includes at least one UPF141. The mobile CN140also includes multiple control plane (“CP”) functions including, but not limited to, an AMF143that serves the RAN120, a Session Management Function (“SMF”)145, a Policy Control Function (“PCF”)147, a Unified Data Management function (“UDM”) and a User Data Repository (“UDR”). In some embodiments, the UDM is co-located with the UDR, depicted as combined entity “UDM/UDR”149. Although specific numbers and types of NFs are depicted inFIG.1, one of skill in the art will recognize that any number and type of NFs may be included in the mobile CN140.

The UPF(s)141is/are responsible for packet routing and forwarding, packet inspection, QoS handling, and external PDU session for interconnecting a DN, in the 5G architecture. The AMF143is responsible for termination of NAS signaling, NAS ciphering and integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The SMF145is responsible for session management (i.e., session establishment, modification, release), remote unit (i.e., UE) Internet Protocol (“IP”) address allocation and management, DL data notification, and traffic steering configuration of the UPF141for proper traffic routing.

As described above, the NSACF146monitors and controls the number of registered remote units105per network slice for the network slices that are subject to NSAC. The PCF147is responsible for unified policy framework, providing policy rules to CP functions, access subscription information for policy decisions in UDR. The PCF147is responsible for unified policy framework, providing policy rules to CP functions, access subscription information for policy decisions in UDR.

The UDM is responsible for generation of Authentication and Key Agreement (“AKA”) credentials, user identification handling, access authorization, subscription management. The UDR is a repository of subscriber information and may be used to service a number of NFs. For example, the UDR may store subscription data, policy-related data, subscriber-related data that is permitted to be exposed to third party applications, and the like. As indicated above, the UDM and UDR may be co-located and/or combined into a single network function (“NF”).

In various embodiments, the mobile CN140may also include a Network Repository Function (“NRF”) (which provides NF service registration and discovery, enabling NFs to identify appropriate services in one another and communicate with each other over Application Programming Interfaces (“APIs”)), a Network Exposure Function (“NEF”) (which is responsible for making network data and resources easily accessible to customers and network partners), an Authentication Server Function (“AUSF”), or other NFs defined for the 5GC. When present, the AUSF may act as an authentication server and/or authentication proxy, thereby allowing the AMF143to authenticate a remote unit105. In certain embodiments, the mobile CN140may include an authentication, authorization, and accounting (“AAA”) server.

In various embodiments, the mobile CN140supports different types of mobile data connections and different types of network slices, wherein each mobile data connection utilizes a specific network slice. Here, a “network slice” refers to a portion of the mobile CN140optimized for a certain traffic type or communication service. For example, one or more network slices may be optimized for enhanced mobile broadband (“eMBB”) service. As another example, one or more network slices may be optimized for ultra-reliable low-latency communication (“URLLC”) service. In other examples, a network slice may be optimized for machine-type communication (“MTC”) service, massive MTC (“mMTC”) service, Internet-of-Things (“IoT”) service. In yet other examples, a network slice may be deployed for a specific application service, a vertical service, a specific use case, etc.

A network slice instance may be identified by a S-NSSAI while a set of network slices for which the remote unit105is authorized to use is identified by NSSAI. Here, “NSSAI” refers to a vector value including one or more S-NSSAI values. In certain embodiments, the various network slices may include separate instances of NFs, such as the SMF145and UPF141. In some embodiments, the different network slices may share some common NFs, such as the AMF143. The different network slices are not shown inFIG.1for ease of illustration, but their support is assumed.

WhileFIG.1depicts components of a 5G RAN and a 5G core network (“5GC”), the described embodiments for registering to a congested network slice apply to other types of communication networks and RATs, including IEEE 802.11 variants, Global System for Mobile Communications (“GSM”, i.e., a 2G digital cellular network), General Packet Radio Service (“GPRS”), Universal Mobile Telecommunications System (“UMTS”), LTE variants, CDMA2000, Bluetooth, ZigBee, Sigfox, and the like.

Moreover, in an LTE variant where the mobile CN140is an EPC, the depicted NFs may be replaced with appropriate EPC entities, such as a Mobility Management Entity (“MME”), a Serving Gateway (“SGW”), a PGW, a Home Subscriber Server (“HSS”), and the like. For example, the AMF143may be mapped to an MME, the SMF145may be mapped to a CP portion of a PGW and/or to an MME, the UPF141may be mapped to an SGW and a UP portion of the PGW, the UDM/UDR149may be mapped to an HSS, etc. Note that the MME is an access management function in the EPS and the AMF143is a corresponding access management function in the 5GS. As used herein, the term “access management function” is used to reference any network entity/function that interacts with the remote unit105to control access to a network slice or similar network resource.

In the following descriptions, the term “gNB” is used for the base station/base unit, but it is replaceable by any other radio access node, e.g., RAN node, ng-eNB, eNB, Base Station (“BS”), Access Point (“AP”), NR BS, 5G NB, Transmission and Reception Point (“TRP”), etc. Additionally, the term “UE” is used for the mobile station/remote unit, but it is replaceable by any other remote device, e.g., remote unit, MS, ME, etc. Further, the operations are described mainly in the context of 5G NR. However, the below described solutions/methods are also equally applicable to other mobile communication systems for registering to a congested network slice.

FIG.2depicts a NR protocol stack200, according to embodiments of the disclosure. WhileFIG.2shows the UE205, the RAN node210and an AMF215in a 5GC, these are representative of a set of remote units105interacting with a base unit121and a mobile CN140. As depicted, the NR protocol stack200comprises a UP protocol stack201and a CP protocol stack203. The UP protocol stack201includes a physical (“PHY”) layer220, a Medium Access Control (“MAC”) sublayer225, the Radio Link Control (“RLC”) sublayer230, a Packet Data Convergence Protocol (“PDCP”) sublayer235, and Service Data Adaptation Protocol (“SDAP”) layer240. The CP protocol stack203includes a PHY layer220, a MAC sublayer225, a RLC sublayer230, and a PDCP sublayer235. The CP protocol stack203also includes a Radio Resource Control (“RRC”) layer245and a NAS layer250.

The AS layer255(also referred to as “AS protocol stack”) for the UP protocol stack201consists of at least SDAP, PDCP, RLC and MAC sublayers, and the physical layer. The AS layer260for the CP protocol stack203consists of at least RRC, PDCP, RLC and MAC sublayers, and the physical layer. The Layer-2 (“L2”) is split into the SDAP, PDCP, RLC and MAC sublayers. The Layer-3 (“L3”) includes the RRC layer245and the NAS layer250for the CP and includes, e.g., an IP layer and/or PDU Layer (not depicted) for the UP. L1 and L2 are referred to as “lower layers,” while L3 and above (e.g., transport layer, application layer) are referred to as “higher layers” or “upper layers.”

The PHY layer220offers transport channels to the MAC sublayer225. The PHY layer220may perform a beam failure detection procedure using energy detection thresholds, as described herein. In certain embodiments, the PHY layer220may send an indication of beam failure to a MAC entity at the MAC sublayer225. The MAC sublayer225offers logical channels to the RLC sublayer230. The RLC sublayer230offers RLC channels to the PDCP sublayer235. The PDCP sublayer235offers radio bearers to the SDAP sublayer240and/or RRC layer245. The SDAP sublayer240offers QoS flows to the CN (e.g., 5GC). The RRC layer245provides for the addition, modification, and release of Carrier Aggregation and/or Dual Connectivity. The RRC layer245also manages the establishment, configuration, maintenance, and release of Signaling Radio Bearers (“SRBs”) and Data Radio Bearers (“DRBs”).

The NAS layer250is between the UE205and the AMF215in the 5GC. NAS messages are passed transparently through the RAN. The NAS layer250is used to manage the establishment of communication sessions and for maintaining continuous communications with the UE205as it moves between different cells of the RAN. In contrast, the AS layers255and260between the UE205and the RAN (i.e., RAN node210) and carries information over the wireless portion of the network. While not depicted inFIG.2, the IP layer exists above the NAS layer250, a transport layer exists above the IP layer, and an application layer exists above the transport layer.

The MAC sublayer225is the lowest sublayer in the L2 architecture of the NR protocol stack. Its connection to the PHY layer220below is through transport channels, and the connection to the RLC sublayer230above is through logical channels. The MAC sublayer225therefore performs multiplexing and demultiplexing between logical channels and transport channels: the MAC sublayer225in the transmitting side constructs MAC PDUs, known as transport blocks, from MAC Service Data Units (“SDUs”) received through logical channels, and the MAC layer225in the receiving side recovers MAC SDUs from MAC PDUs received through transport channels.

The MAC sublayer225provides a data transfer service for the RLC layer230through logical channels, which are either control logical channels which carry control data (e.g., RRC signaling) or traffic logical channels which carry UP data. On the other hand, the data from the MAC sublayer225is exchanged with the PHY layer220through transport channels, which are classified as DL or UL. Data is multiplexed into transport channels depending on how it is transmitted over the air.

The PHY layer220is responsible for the actual transmission of data and control information via the air interface, i.e., the PHY Layer220carries all information from the MAC transport channels over the air interface on the transmission side. Some of the important functions performed by the PHY layer220include coding and modulation, link adaptation (e.g., Adaptive Modulation and Coding (“AMC”)), power control, cell search and random access (for initial synchronization and handover purposes) and other measurements (inside the 3GPP system (i.e., NR and/or LTE system) and between systems) for the RRC layer245. The PHY layer220performs transmissions based on transmission parameters, such as the modulation scheme, the coding rate (i.e., the modulation and coding scheme (“MCS”)), the number of physical resource blocks, etc.

In case one or more S-NSSAIs are congested, a UE cannot register with them and at the time of registration. However, if the congestion is resolved (e.g., a current number of registered UEs per network slice of a requested S-NSSAI drops below the limit), there should be a mechanism to inform the UE, in case the UE is to attempt a new registration for the one or more S-NSSAIs. Accordingly, the ER-NSSAI IE is defined which groups one or more S-NSSAIs with an assigned back-off timer for indicating to the UE when the UE can retry to register with the one or more S-NSSAIs.

FIG.3shows one example of an ER-NSSAI IE300, according to embodiments of the disclosure. As noted above, the ER-NSSAI IE300is used to identify a set of rejected S-NSSAI. In the ER-NSSAI IE300, the first octet comprises an IE identifier (“IEI”) used to indicate that the ER-NSSAI IE300is an ER-NSSAI IE. The second octet comprises a length field indicating the length of the ER-NSSAI contents.

The value portion305of the ER-NSSAI IE300(i.e., composed of octets3to v) is composed of one or more partial extended rejected NSSAI lists, described in greater detail with reference toFIG.4. In some embodiments, the number of rejected S-NSSAI in the ER-NSSAI IE300is limited to eight or less.

FIG.4shows one example of a partial extended rejected NSSAI list400, according to embodiments of the disclosure. Each partial extended rejected NSSAI list includes a back-off timer value and a list of up to eight S-NSSAI. Each rejected S-NSSAI includes an S-NSSAI (to identify a respective network slice) and a cause value. In various embodiments, one or more values of a 4-bit cause value field (not depicted inFIG.4) may encode an indication that the network slice (e.g., identified by S-NSSAI) is rejected for NSAC reasons, for example, indicating that the S-NSSAI is not available due to a maximum number of UEs being reached.

The back-off timer value indicates how long the UE should wait before again attempting to register with a respective network slice (e.g., identified by S-NSSAI) that was rejected for NSAC reasons. However, as described above, a legacy UE that does not support ER-NSSAI (e.g., a model of UE from before implementation of the ER-NSSAI) would not be capable of interpreting the ER-NSSAI IE and implementing the back-off timer.

FIG.5shows one example of a 5GMM IE500, according to embodiments of the disclosure Because the support of ER-NSSAI is optional for the UE, the UE needs to inform the network at the time of registration that the UE is capable of ER-NSSAI. This is done by a defined bit of the 5GMM capability IE, i.e., ER-NSSAI field505. In some embodiments, the value of ER-NSSAI is set to “1” to indicate that the UE supports ER-NSSAI, but is set to “0” if the UE does not support the ER-NSSAI. Note that a pre-release 16 UE does not support this new 5GMM capability.

It is optional for the UE to support this ER-NSSAI mechanism, therefore the UE may not support the new ER-NSSAI, and the network may not be able to inform the UE about the back-off timer to indicate when the rejected NSSAI can be used.

Additionally, the network must have good analytics to estimate the back-off timer correctly, otherwise, it may result in new registration attempts by the UE where the UE may again be denied registration with the one or more S-NSSAIs with new back-off timers. This may also cause extra, unnecessary signaling due to registration procedure. For example, the network may lack the analytics to estimate the availability times for the rejected one or more S-NSSAIs due to being exhausted by many UEs are using them, and to then communicate those times with the UE via the new ER-NSSAI.

According to embodiments of a first solution, the network may trigger the UE for a new registration with one or more S-NSSAIs, if the network has rejected the UE those one or more S-NSSAIs in an earlier registration and if one or some of the one or more S-NSSAIs are not congested.

FIG.6shows one example of a procedure600for registration, according to embodiments of the disclosure. The procedure600involves a UE601, an Access Network (“AN”)603, an AMF605, a SMF607, and a UPF609. The UE601may be one implementation of the remote unit105and/or the UE205. The AN603may be one implementation of the RAN120comprising a base unit121and/or the RAN node210. The AMF605may be one implementation of the AMF143and/or AMF215. The SMF607may be one implementation of the SMF145. The UPF609may be one implementation of the UPF141. A detailed description of the steps of the procedure600is as follows:

At Step1, the UE601attempts to register with one or more S-NSSAI to the 5GC (see block611). Here, it is assumed that the UE601does not support the ER-NSSAI and therefore may set ER-NSSAI to “0” (or does not include the ER-NSSAI IE at all) in the 5GMM capability IE of the REGISTRATION REQUEST message sent to the AMF605via the AN603. Note that the registration to the 5GC may be based on 3GPP RAN or non-3GPP access technology.

At least one of the one or more S-NSSAIs are subject to NSAC and the maximum number of UEs has been reached. Therefore, the network (e.g., the AMF605, or together with a Network Slice Selection Function (“NSSF”) and/or NSACF) determines which of the requested S-NSSAIs and the subscribed S-NSSAIs can be used by the UE601.

If the UE supports ER-NSSAI, then the AMF605may send a registration accept message to accept the UE's registration and includes a Rejected NSSAI IE comprising those one or more S-NSSAIs for which the maximum number of UEs is reached. Note that the registration accept message may also include an Allowed NSSAI IE to indicate a network slice (S-NSSAI) that is not subject to NSAC or for which the maximum number of UEs is not reached. The Rejected NSSAI IE and the Allowed NSSAI IE each comprise a list of one or more S-NSSAI for which UE registration is rejected or allowed, respectively.

However, in the depicted embodiment the network does not use the ER-NSSAI IE, because the UE601did not include the ER-NSSAI capability IE or the ER-NSSAI bit is set to “1” and/or the network does not have a good analytics to estimate the back-off timer for the one or more rejected congested S-NSSAIs and therefore may not choose to use ER-NSSAI IE. For example, if the network lacks the analytics to estimate the availability times for the rejected one or more S-NSSAIs due to being exhausted by many UEs are using them, and to then communicate those times with the UE601via the new ER-NSSAI, then the network (e.g., AMF605) may choose not to use the ER-NSSAI when registration to a S-NSSAI is rejected due to congestion/exhaustion of the network slice. With other words, the ER-NSSAI is only a tool which is used by the network to indicate, to a respective UE, the availability time for one or more S-NSSAIs subject to NSAC.

If the UE601does not indicate support for ER-NSSAI and the maximum number of UEs has been reached, then the AMF605includes the rejected NSSAI containing the one or more S-NSSAIs for which the maximum number of UEs is reached and does not include these S-NSSAIs in the allowed NSSAI. Note that the registration accept message may also include an Allowed NSSAI IE to indicate a network slice (e.g., identified by S-NSSAI) that is not subject to NSAC or for which the maximum number of UEs is not reached.

Note that, based on network policies, the AMF605can indicate the S-NSSAI(s) for which the maximum number of UEs has been reached in the rejected NSSAI with rejection causes other than “S-NSSAI not available in the current PLMN or SNPN”. For example, the AMF605may set the cause value to indicate that the S-NSSAI is not available in the network or registration area.

In addition, based on the network policies, the AMF605may start a local implementation specific timer for the UE601per rejected S-NSSAI.

At Step2, the AMF605may have stored a status that the particular one or more S-NSSAIs were rejected for the maximum number of UEs reached, and optionally a time stamp when it was rejected, in the UE mobility context. If one or more S-NSSAIs, which were subject to NSAC with the reached maximum number of UEs but now, to which maximum number of UEs is not reached, the network (e.g., AMF605) may check if the UE601was denied access to the one or more of these S-NSSAIs. The network (e.g., AMF605) may also verify if the one or more S-NSSAIs are allowable, e.g., whether the one or more S-NSSAI can be used by the UE601in the current location and current AMF605, by checking the UE's subscription information and stored mobility context.

If the one or more S-NSSAI subject to NSAC is available again (e.g., if the current number of registered UEs is lower than the maximum number of UEs), and there are multiple UEs to which the one of more S-NSSAI was rejected for the maximum number of UEs reached, the AMF605may assess: A) the time stamp of each stored status of the rejected S-NSSAI in the UEs contexts; and/or B) the subscription priority type of the UEs, and the AMF605may determine which UE(s) should be updated first.

At Step3, the AMF605updates the UE601by performing a generic UE Configuration Update procedure (see block615). Based on network policies, upon expiration of the local implementation specific timer, the AMF605may remove the rejected S-NSSAI from the rejected NSSAI and update to the UE601by initiating the generic UE Configuration Update procedure. In various embodiments, the UE601receives an indication that the previously rejected S-NSSAI (e.g., rejected for NSAC reasons) is excluded from the rejected NSSAI. Note that the generic UE Configuration Update procedure may or may not require the UE601to perform a (new) registration procedure.

In other words, the AMF605may transmit the new allowed NSSAI and/or the new rejected NSSAI (which does not contain the previously rejected one or more S-NSSAIs rejected for NSAC reasons) to the UE601, e.g., by using the CONFIGURATION UPDATE COMMAND message. The AMF605may request for an acknowledgement which is transmitted by the UE601, e.g., by a CONFIGURATION UPDATE COMPLETE message. In certain embodiments, where the rejected NSSAI consisted solely of the previously rejected S-NSSAI (e.g., rejected for NSAC reasons), then the AMF605may instruct the UE601to delete the complete rejected NSSAI. Note that the UE's rejected NSSAI can still exist with other S-NSSAIs.

At Step4, the UE601initiates a mobility update registration (“MUR”) to request the network (e.g., AMF605) to evaluate whether the one or more S-NSSAIs within the set of rejected NSSAI can be allowed by the network and if so, the UE601can use them (see block617). In some embodiments, the S-NSSAI previously rejected for NSAC reasons does not get automatically allowed when the timer is expired. Here, the AMF605will not send an update message that the S-NSSAI which was rejected is now allowed. Rather, the AMF605just indicates to the UE601that S-NSSAI is not in the rejected NSSAI anymore (i.e., the S-NSSAI is not rejected any longer), therefore the UE601can let the network evaluate whether the S-NSSAI is allowed by performing MUR and including the S-NSSAI in the configured NSSAI. Once the network authenticated and authorized it, then the UE601receives that S-NSSAI in the allowed NSSAI.

At Step4, the UE601is updated that it may use the one or more previously rejected S-NSSAI(s). The UE601may initiate a new registration procedure to include the one or more S-NSSAIs in the requested NSSAI. After a successful registration to the one or more S-NSSAIs, i.e., the one or more S-NSSAIs are included in the allowed S-NSSAI and/or excluded from the rejected NSSAI, the UE601may initiate a PDU session establishment procedure over the one or more S-NSSAIs (see block619).

If the UE601has received an updated allowed NSSAI including the one or more S-NSSAIs and/or an updated rejected NSSAI including the one or more S-NSSAIs, the UE601can directly initiate the PDU session establishment procedure over the one or more S-NSSAIs (i.e., without a new registration procedure).

Note that the generic UE configuration update procedure may be over 3GPP RAN or non-3GPP access technology. Also, note that due to the nature of one or more S-NSSAI and/or UE's subscription information, the network may prioritize other UEs for assigning the one or more S-NSSAIs to and therefore the one or more S-NSSAIs may become part of rejected NSSAI for the maximum number of UEs reached for the UE601. In that case, the network may use the same generic UE configuration update procedure to inform the UE601that the one or more S-NSSAIs are not in allowed NSSAI and/or they are in rejected NSSAI.

FIG.7depicts a UE apparatus700that may be used for registering to a congested network slice, according to embodiments of the disclosure. In various embodiments, the UE apparatus700is used to implement one or more of the solutions described above. The UE apparatus700may be one embodiment of a UE endpoint, such as the remote unit105, the UE205, and/or the UE601, as described above. Furthermore, the UE apparatus700may include a processor705, a memory710, an input device715, an output device720, and a transceiver725.

In some embodiments, the input device715and the output device720are combined into a single device, such as a touchscreen. In certain embodiments, the UE apparatus700may not include any input device715and/or output device720. In various embodiments, the UE apparatus700may include one or more of: the processor705, the memory710, and the transceiver725, and may not include the input device715and/or the output device720.

As depicted, the transceiver725includes at least one transmitter730and at least one receiver735. In some embodiments, the transceiver725communicates with one or more cells (or wireless coverage areas) supported by one or more base units121. In various embodiments, the transceiver725is operable on unlicensed spectrum. Moreover, the transceiver725may include multiple UE panels supporting one or more beams. Additionally, the transceiver725may support at least one network interface740and/or application interface745. The application interface(s)745may support one or more APIs. The network interface(s)740may support 3GPP reference points, such as Uu, N1, PC5, etc. Other network interfaces740may be supported, as understood by one of ordinary skill in the art.

The processor705, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor705may be a microcontroller, a microprocessor, a central processing unit (“CPU”), a graphics processing unit (“GPU”), an auxiliary processing unit, a field programmable gate array (“FPGA”), or similar programmable controller. In some embodiments, the processor705executes instructions stored in the memory710to perform the methods and routines described herein. The processor705is communicatively coupled to the memory710, the input device715, the output device720, and the transceiver725.

In various embodiments, the processor705controls the UE apparatus700to implement the above described UE behaviors. In certain embodiments, the processor705may include an application processor (also known as “main processor”) which manages application-domain and operating system (“OS”) functions and a baseband processor (also known as “baseband radio processor”) which manages radio functions.

In various embodiments, via the transceiver725, the processor705sends a registration request to register to a network slice (e.g., identified by S-NSSAI) in a mobile communication network, where the network slice subject to NSAC. Note that the solutions described herein do not require that the apparatus700be aware that the requested NSSAI is subject to NSAC.

In some embodiments, the processor is further configured to cause the apparatus to send, to the access management function (e.g., an AMF or MME), capability information (e.g., a 5GMM capability IE) including an indication that the communication device does not support ER-NSSAI (e.g., ER-NSSAI capability IE is set to ‘0’ or no ER-NSSAI capability IE sent). In certain embodiments, the registration request includes the indication that the communication device does not support ER-NSSAI.

Via the transceiver725, the processor705receives, from an access management function (e.g., an AMF or MME), a first response including an allowed set of network slices and a first indication (e.g., rejected NSSAI) that rejects registration to the network slice. In some embodiments, the first response includes a rejected NSSAI that indicates/identifies the network slice and contains a non-NSAC-based rejection cause value, such as a cause value indicating that the S-NSSAI is not available in the network or registration area. Here, the rejected NSSAI contains S-NSSAI that corresponds to the network slice.

Via the transceiver725, the processor705receives, from the access management function (e.g., an AMF or MME), a second response including an indication that the communication device is permitted to register to the network slice and establishes a data connection (e.g., a PDU session) using the network slice. In some embodiments, the second response is received during a UE configuration update procedure. In certain embodiments, the UE configuration update procedure requires new registration to the mobile communication network.

In some embodiments, to indicate that the communication device is permitted to register to the network slice (e.g., initiate MUR to request the network evaluate whether registration to the network slice can be allowed by the network), the update message contains updated rejected NSSAI that excludes (e.g., does not contain) the S-NSSAI corresponding to the network slice. In certain embodiments, to indicate that the communication device is permitted to register to the network slice, the second response (e.g., an update message) includes an indication that the rejected NSSAI is to be deleted (e.g., because the rejected NSSAI contained only the S-NSSAI of the network slice subject to NSAC).

The memory710, in one embodiment, is a computer readable storage medium. In some embodiments, the memory710includes volatile computer storage media. For example, the memory710may include a RAM, including dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or static RAM (“SRAM”). In some embodiments, the memory710includes non-volatile computer storage media. For example, the memory710may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory710includes both volatile and non-volatile computer storage media.

In some embodiments, the memory710stores data related to registering to a congested network slice. For example, the memory710may store various parameters, panel/beam configurations, resource assignments, policies, and the like as described above. In certain embodiments, the memory710also stores program code and related data, such as an operating system or other controller algorithms operating on the UE apparatus700.

The input device715, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device715may be integrated with the output device720, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, the input device715includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device715includes two or more different devices, such as a keyboard and a touch panel.

In certain embodiments, the output device720includes one or more speakers for producing sound. For example, the output device720may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device720includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the output device720may be integrated with the input device715. For example, the input device715and output device720may form a touchscreen or similar touch-sensitive display. In other embodiments, the output device720may be located near the input device715.

The transceiver725communicates with one or more NFs of a mobile communication network via one or more access networks. The transceiver725operates under the control of the processor705to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor705may selectively activate the transceiver725(or portions thereof) at particular times in order to send and receive messages.

The transceiver725includes at least transmitter730and at least one receiver735. One or more transmitters730may be used to provide UL communication signals to a base unit121, such as the UL transmissions described herein. Similarly, one or more receivers735may be used to receive DL communication signals from the base unit121, as described herein. Although only one transmitter730and one receiver735are illustrated, the UE apparatus700may have any suitable number of transmitters730and receivers735. Further, the transmitter(s)730and the receiver(s)735may be any suitable type of transmitters and receivers. In one embodiment, the transceiver725includes a first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and a second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum.

In certain embodiments, the first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and the second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum may be combined into a single transceiver unit, for example a single chip performing functions for use with both licensed and unlicensed radio spectrum. In some embodiments, the first transmitter/receiver pair and the second transmitter/receiver pair may share one or more hardware components. For example, certain transceivers725, transmitters730, and receivers735may be implemented as physically separate components that access a shared hardware resource and/or software resource, such as for example, the network interface740.

In various embodiments, one or more transmitters730and/or one or more receivers735may be implemented and/or integrated into a single hardware component, such as a multi-transceiver chip, a system-on-a-chip, an Application-Specific Integrated Circuit (“ASIC”), or other type of hardware component. In certain embodiments, one or more transmitters730and/or one or more receivers735may be implemented and/or integrated into a multi-chip module. In some embodiments, other components such as the network interface740or other hardware components/circuits may be integrated with any number of transmitters730and/or receivers735into a single chip. In such embodiment, the transmitters730and receivers735may be logically configured as a transceiver725that uses one more common control signals or as modular transmitters730and receivers735implemented in the same hardware chip or in a multi-chip module.

FIG.8depicts a network apparatus800that may be used for registering to a congested network slice, according to embodiments of the disclosure. In one embodiment, network apparatus800may be one implementation of a network endpoint, such as the base unit121and/or RAN node207, as described above. Furthermore, the network apparatus800may include a processor805, a memory810, an input device815, an output device820, and a transceiver825.

In some embodiments, the input device815and the output device820are combined into a single device, such as a touchscreen. In certain embodiments, the network apparatus800may not include any input device815and/or output device820. In various embodiments, the network apparatus800may include one or more of: the processor805, the memory810, and the transceiver825, and may not include the input device815and/or the output device820.

As depicted, the transceiver825includes at least one transmitter830and at least one receiver835. Here, the transceiver825communicates with one or more remote units105. Additionally, the transceiver825may support at least one network interface840and/or application interface845. The application interface(s)845may support one or more APIs. The network interface(s)840may support 3GPP reference points, such as Uu, N1, N2 and N3. Other network interfaces840may be supported, as understood by one of ordinary skill in the art.

The processor805, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor805may be a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or similar programmable controller. In some embodiments, the processor805executes instructions stored in the memory810to perform the methods and routines described herein. The processor805is communicatively coupled to the memory810, the input device815, the output device820, and the transceiver825.

In various embodiments, the network apparatus800is a RAN node (e.g., gNB) that communicates with one or more UEs, as described herein. In such embodiments, the processor805controls the network apparatus800to perform the above described RAN behaviors. In some embodiments, the network apparatus800may configure one or more endpoint devices with the Training Sequences to be used in the key verification procedure. When operating as a RAN node, the processor805may include an application processor (also known as “main processor”) which manages application-domain and OS functions and a baseband processor (also known as “baseband radio processor”) which manages radio functions.

In various embodiments, via the transceiver825, the processor805receives a registration request from the communication device to register to a network slice (e.g., identified by S-NSSAI) subject to NSAC. Note that the solutions described herein do not require that the communication device (e.g., a UE) be aware that the requested S-NSSAI is subject to NSAC.

The processor805determines that registration to the network slice is rejected for NSAC (e.g., because a maximum number of UEs is reached). In some embodiments, to determine that the registration to the network slice is rejected, the processor805receives (e.g., via the transceiver825) an indication from a NF (e.g., NSSF or NSACF) that a limit is reached for a network slice attribute for the network slice subject to NSAC. For example, a maximum number of registered UEs per network slice may be reached for a particular S-NSSAI requested by the communication device. As used herein, an “indication” could be an explicit indication-such as an error code, flag, parameter, IE, etc.—or could be an implicit indication—e.g., inferred from a message type, a sender/receiver, the absence of another indication/parameter, etc.

In some embodiments, the processor805sends (e.g., via the transceiver825) rejected NSSAI to the communication device in response to determining that the registration to the network slice is rejected. In such embodiments, the rejected NSSAI indicates/identifies the network slice and contains a non-NSAC-based rejection cause value, such as a cause value indicating that the S-NSSAI is not available in the network or registration area.

The processor805initiates a timer in response to determining that the registration to the network slice is rejected. In some embodiments, the processor805determines that the network apparatus800lacks analytics information to support ER-NSSAI. In such embodiments, the processor805initiates the timer in response to determining that the network apparatus800lacks analytics information to support ER-NSSAI.

In other embodiments, the processor805determines that the communication device does not support ER-NSSAI and initiates the timer in response to determining that the communication device does not support ER-NSSAI. In certain embodiments, to determine that the communication device does not support ER-NSSAI, the processor805receives (e.g., via the transceiver825) capability information that includes an indication that the communication device does not support ER-NSSAI. For example, the transceiver825may receive, from the communication device, a 5GMM capability IE that either contains an ER-NSSAI capability IE is set to ‘0’ or does not contain any ER-NSSAI capability IE.

Via the transceiver825, the processor805sends, to the communication device, an update message in response to expiry of the timer, the update message containing an indication that the communication device is permitted to register to the network slice. In some embodiments, to send the update message, the processor805initiates a UE configuration update procedure.

In some embodiments, to indicate that the communication device is permitted to register to the network slice (e.g., signal that the communication device may initiate MUR to request the network evaluate whether registration to the network slice can be allowed by the network), the update message contains updated rejected NSSAI that excludes (e.g., does not contain) the S-NSSAI corresponding to the network slice. In certain embodiments, to indicate that the communication device is permitted to register to the network slice, the update message contains an indication that the rejected NSSAI is to be deleted (e.g., because the rejected NSSAI contained only the S-NSSAI of the network slice subject to NSAC).

In certain embodiments, the processor805maps a NSAC-based rejection cause value to a non-NSAC-based rejection cause value in response to determining that the communication device does not support ER-NSSAI and, via the transceiver825, sends rejected NSSAI to the communication device. In such embodiments, the rejected NSSAI indicates the network slice and contains the non-NSAC-based rejection cause value. Here, the rejected NSSAI contains S-NSSAI that corresponds to the network slice.

In some embodiments, the processor805stores, for the communication device, context information containing rejected NSSAI which indicates that the network slice was rejected for NSAC. Additionally, the processor805determines whether the network slice is again available (e.g., because the NSAC limit is no longer met). In response to determining that the network slice is again available, the processor sends the update message.

The memory810, in one embodiment, is a computer readable storage medium. In some embodiments, the memory810includes volatile computer storage media. For example, the memory810may include a RAM, including DRAM, SDRAM, and/or SRAM. In some embodiments, the memory810includes non-volatile computer storage media. For example, the memory810may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory810includes both volatile and non-volatile computer storage media.

In some embodiments, the memory810stores data related to registering to a congested network slice. For example, the memory810may store parameters, configurations, resource assignments, policies, and the like, as described above. In certain embodiments, the memory810also stores program code and related data, such as an operating system or other controller algorithms operating on the network apparatus800.

The input device815, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device815may be integrated with the output device820, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, the input device815includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device815includes two or more different devices, such as a keyboard and a touch panel.

In certain embodiments, the output device820includes one or more speakers for producing sound. For example, the output device820may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device820includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the output device820may be integrated with the input device815. For example, the input device815and output device820may form a touchscreen or similar touch-sensitive display. In other embodiments, the output device820may be located near the input device815.

The transceiver825includes at least transmitter830and at least one receiver835. One or more transmitters830may be used to communicate with the UE, as described herein. Similarly, one or more receivers835may be used to communicate with NFs in the PLMN and/or RAN, as described herein. Although only one transmitter830and one receiver835are illustrated, the network apparatus800may have any suitable number of transmitters830and receivers835. Further, the transmitter(s)830and the receiver(s)835may be any suitable type of transmitters and receivers.

FIG.9depicts one embodiment of a method900for registering to a congested network slice, according to embodiments of the disclosure. In various embodiments, the method900is performed by a network device, such as the AMF143, the AMF215, the AMF605, and/or the network apparatus800, as described above. In some embodiments, the method900is performed by a processor, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method900includes receiving905a registration request from a communication device (e.g., a UE) to register to a network slice (i.e., identified by S-NSSAI) subject to NSAC. The method900includes determining910that registration to the network slice is rejected for NSAC (e.g., because a maximum number of UEs is reached). The method900includes initiating915a timer in response to determining that the registration to the network slice is rejected. The method900includes sending920, to the communication device, an update message in response to expiry of the timer, the update message containing an indication that the communication device is permitted to register to the network slice. The method900ends.

FIG.10depicts one embodiment of a method1000for registering to a congested network slice, according to embodiments of the disclosure. In various embodiments, the method1000is performed by a communication device, such as the remote unit105, the UE205, the UE601, and/or the UE apparatus700, described above, as described above. In some embodiments, the method1000is performed by a processor, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method1000includes sending1005, by the communication device, a registration request to register to a network slice (e.g., identified by S-NSSAI) in a mobile communication network, the network slice subject to NSAC. The method1000includes receiving1010, from an access management function (e.g., an AMF or MME), a first response including an allowed set of network slices and a first indication (e.g., rejected NSSAI) that rejects registration to the network slice. The method1000includes receiving1015, from the access management function, a second response including a second indication that the communication device is permitted to register to the network slice. The method1000includes establishing1020, by the communication device, a data connection (e.g., a PDU session) using the network slice. The method1000ends.

Disclosed herein is a first apparatus for registering to a congested network slice, according to embodiments of the disclosure. The first apparatus may be implemented by a network device, such as the AMF143, the AMF215, the AMF605, and/or the network apparatus800, described above. The first apparatus includes a processor coupled to a transceiver, the transceiver configured to communicate with a communication device (e.g., a UE) and the processor configured to cause the apparatus to: A) receive a registration request from the communication device to register to a network slice (e.g., identified by S-NSSAI) subject to NSAC: B) determine that a registration to the network slice is rejected for NSAC (e.g., because a maximum number of UEs is reached): C) initiate a timer in response to the registration to the network slice being rejected; and D) send, to the communication device, an update message in response to expiry of the timer, the update message including a first indication that the communication device is permitted to register to the network slice.

In some embodiments, the processor is further configured to cause the apparatus to determine that the communication device does not support ER-NSSAI. In such embodiments, the processor is configured to cause the apparatus to initiate the timer in response to determining that the communication device does not support ER-NSSAI. In certain embodiments, to determine that the communication device does not support ER-NSSAI, the processor is configured to cause the apparatus to receive capability information (e.g., a 5GMM capability IE) including a second indication that the communication device does not support ER-NSSAI (e.g., ER-NSSAI capability IE is set to ‘0’ or no ER-NSSAI capability IE sent).

In certain embodiments, the processor is further configured to cause the apparatus to: A) map a NSAC-based rejection cause value to a non-NSAC-based rejection cause value in response to determining that the communication device does not support ER-NSSAI; and B) send rejected NSSAI to the communication device, where the rejected NSSAI indicates the network slice and includes the non-NSAC-based rejection cause value.

In some embodiments, the processor is further configured to cause the apparatus to determine that the first apparatus lacks analytics information to support ER-NSSAI. In such embodiments, the processor is configured to cause the apparatus to initiate the timer in response to determining that the first apparatus lacks analytics information to support ER-NSSAI.

In some embodiments, to determine that the registration to the network slice is rejected, the processor is configured to cause the apparatus to receive an indication from a NF (e.g., NSSF or NSACF) that a maximum number of registered users is reached for the network slice.

In some embodiments, the processor is further configured to cause the apparatus to send rejected NSSAI to the communication device. In such embodiments, the rejected NSSAI indicates the network slice and includes a non-NSAC-based rejection cause value. Here, the rejected NSSAI contains S-NSSAI that corresponds to the network slice. In further embodiments, to indicate that the communication device is permitted to register to the network slice, the update message contains updated rejected NSSAI that excludes (e.g., does not contain) the S-NSSAI corresponding to the network slice. In certain embodiments, to indicate that the communication device is permitted to register to the network slice, the update message includes an indication that the rejected NSSAI is to be deleted (e.g., because the rejected NSSAI contained only the S-NSSAI of the network slice subject to NSAC).

In some embodiments, the processor is further configured to cause the apparatus to: A) store, for the communication device, mobility context information including rejected NSSAI which indicates that the network slice was rejected for NSAC; and B) determine that the network slice is again available (e.g., because the NSAC limit is no longer met). In such embodiments, the processor is configured to cause the apparatus to send the update message in response to determining that the network slice is again available. In some embodiments, to send the update message, the processor is configured to cause the apparatus to initiate a UE configuration update procedure.

Disclosed herein is a first method for registering to a congested network slice, according to embodiments of the disclosure. The first method may be performed by a network device, such as the AMF143, the AMF215, the AMF605, and/or the network apparatus800, described above. The first method includes receiving a registration request from a communication device (e.g., a UE) to register to a network slice (i.e., identified by S-NSSAI) subject to NSAC and determining that registration to the network slice is rejected for NSAC (e.g., because a maximum number of UEs is reached). The first method includes initiating a timer in response to determining that the registration to the network slice is rejected and sending, to the communication device, an update message in response to expiry of the timer, the update message including an indication that the communication device is permitted to register to the network slice.

In some embodiments, the first method includes determining that the communication device does not support ER-NSSAI. In such embodiments, initiating the timer occurs in response to determining that the communication device does not support ER-NSSAI. When determining that the communication device does not support ER-NSSAI, the first method may include receiving capability information (e.g., a 5GMM capability IE) including an indication that the communication device does not support ER-NSSAI (e.g., ER-NSSAI capability IE is set to ‘0’ or no ER-NSSAI capability IE sent).

In certain embodiments, in response to determining that the communication device does not support ER-NSSAI, the first method may include mapping a NSAC-based rejection cause value to a non-NSAC-based rejection cause value and sending rejected NSSAI to the communication device, where the rejected NSSAI indicates the network slice and includes the non-NSAC-based rejection cause value.

In some embodiments, the first method includes determining that the access management function lacks analytics information to support ER-NSSAI. In such embodiments, initiating the timer occurs in response to determining that the access management function lacks analytics information to support ER-NSSAI. In some embodiments, determining that the registration to the network slice is rejected includes the network device (e.g., an access management function) receiving an indication from a NF (e.g., NSSF or NSACF) that a maximum number of registered users is reached for the network slice.

In some embodiments, the first method further includes sending rejected NSSAI to the communication device. In such embodiments, the rejected NSSAI indicates the network slice and includes a non-NSAC-based rejection cause value. Here, the rejected NSSAI contains S-NSSAI that corresponds to the network slice. In further embodiments, to indicate that the communication device is permitted to register to the network slice, the update message contains updated rejected NSSAI that excludes (e.g., does not contain) the S-NSSAI corresponding to the network slice. In some embodiments, to indicate that the communication device is permitted to register to the network slice, the update message may include an indication that the rejected NSSAI is to be deleted (e.g., because the rejected NSSAI contained only the S-NSSAI of the network slice subject to NSAC).

In some embodiments, the first method further includes storing, for the communication device, mobility context information including rejected NSSAI which indicates that the network slice was rejected for NSAC and determining whether the network slice is again available. In such embodiments, sending the update message further occurs in response to determining that the network slice is again available (e.g., the NSAC limit is underrun). In some embodiments, sending the update message includes initiating a UE configuration update procedure.

Disclosed herein is a second apparatus for registering to a congested network slice, according to embodiments of the disclosure. The second apparatus may be implemented by a communication device, such as the remote unit105, the UE205, the UE601, and/or the UE apparatus700, described above. The second apparatus includes a processor coupled to a transceiver, the transceiver configured to communicate with a mobile communication network and the processor configured to cause the apparatus to: A) send a registration request to register to a network slice (e.g., identified by S-NSSAI) in a mobile communication network, the network slice subject to NSAC: B) receive, from an access management function (e.g., an AMF or MME), a first response including an allowed set of network slices and an indication (e.g., rejected NSSAI) that rejects registration to the network slice: C) receive, from the access management function, a second response including an indication that the communication device is permitted to register to the network slice; and D) establish a data connection (e.g., a PDU session) using the network slice.

In some embodiments, the second response is received during a UE configuration update procedure. In certain embodiments, the UE configuration update procedure requires new registration to the mobile communication network. In some embodiments, the processor is further configured to cause the apparatus to send, to the access management function, capability information (e.g., a 5GMM capability IE) including an indication that the communication device does not support ER-NSSAI (e.g., ER-NSSAI capability IE is set to ‘0’ or no ER-NSSAI capability IE sent). In certain embodiments, the registration request includes the indication that the communication device does not support ER-NSSAI.

In some embodiments, the first response includes a rejected NSSAI that indicates the network slice and includes a non-NSAC-based rejection cause value. Here, the rejected NSSAI contains S-NSSAI that corresponds to the network slice. In some embodiments, to indicate that the communication device is permitted to register to the network slice, the update message contains updated rejected NSSAI that excludes (e.g., does not contain) the S-NSSAI corresponding to the network slice. In certain embodiments, to indicate that the communication device is permitted to register to the network slice, the second response (e.g., an update message) includes an indication that the rejected NSSAI is to be deleted (e.g., because the rejected NSSAI contained only the S-NSSAI of the network slice subject to NSAC).

Disclosed herein is a second method for registering to a congested network slice, according to embodiments of the disclosure. The second method may be performed by a communication device, such as the remote unit105, the UE205, the UE601, and/or the UE apparatus700, described above. The second method includes sending, by the communication device, a registration request to register to a network slice (e.g., identified by S-NSSAI) in a mobile communication network, the network slice subject to NSAC and receiving, from an access management function (e.g., an AMF or MME), a first response including an allowed set of network slices and an indication (e.g., rejected NSSAI) that rejects registration to the network slice. The second method includes receiving, from the access management function, a second response including an indication that the communication device is permitted to register to the network slice and establishing, by the communication device, a data connection (e.g., a PDU session) using the network slice.

In some embodiments, the second response is received during a UE configuration update procedure, where the UE configuration update procedure requires new registration to the mobile communication network. In some embodiments, the second method further including sending, to the access management function, capability information (e.g., a 5GMM capability IE) including an indication that the communication device does not support ER-NSSAI (e.g., ER-NSSAI capability IE is set to ‘0’ or no ER-NSSAI capability IE sent). In certain embodiments, the registration request includes the indication that the communication device does not support ER-NSSAI.

In some embodiments, the first response includes a rejected NSSAI that indicates the network slice and includes a non-NSAC-based rejection cause value. Here, the rejected NSSAI contains S-NSSAI that corresponds to the network slice. In some embodiments, to indicate that the communication device is permitted to register to the network slice, the update message contains updated rejected NSSAI that excludes (e.g., does not contain) the S-NSSAI corresponding to the network slice. In certain embodiments, to indicate that the communication device is permitted to register to the network slice, the second response (e.g., an update message) includes an indication that the rejected NSSAI is to be deleted (e.g., because the rejected NSSAI contained only the S-NSSAI of the network slice subject to NSAC).