CN117015077A - Method and user equipment for processing maximum number of protocol data unit sessions - Google Patents

Abstract

The embodiment of the invention provides a method and user equipment for processing a maximum number of protocol data unit sessions. Wherein the method comprises: maintaining, by a UE, a plurality of subscriptions for accessing a SNPN, wherein the UE supports accessing the SNPN using credentials from a credential holder; selecting a first subscription to access the selected SNPN, wherein the UE maintains a first maximum number of PDU sessions associated with the first subscription for the selected SNPN; and selecting a second subscription to access the selected SNPN, wherein the UE maintains a second maximum number of PDU sessions associated with the second subscription for the selected SNPN. By utilizing the present invention, the maximum number of PDU sessions can be better handled.

Description

Method and user equipment for processing maximum number of protocol data unit sessions

Technical Field

The present invention relates to wireless mobile communication networks, and more particularly to a method of handling a maximum number of protocol data unit (protocol data unit, PDU) sessions per subscription (subscription) per network.

Background

The public land mobile network (public land mobile network, PLMN) is a network established and operated by a regulatory agency or approved operating agency (recognized operating agency, ROA) for providing land mobile communication services to the public. The PLMN provides communication possibilities for mobile subscribers. The PLMN may provide services in one frequency band or a combination of frequency bands. Access to PLMN services may be achieved through an air interface involving radio communications between a mobile telephone and a base station having integrated IP network services. One PLMN may include multiple radio access networks (radio access network, RAN) utilizing different radio access technologies (radio access network, RATs) to access mobile services. The radio access network is part of a mobile communication system implementing radio access technology. Conceptually, the RAN resides between mobile devices and provides connectivity to its Core Network (CN). According to standards, mobile phones and other wireless connectivity devices may be referred to as User Equipment (UE), terminal equipment (terminal equipment, TE), mobile Station (MS), mobile terminal (mobile termination, MT), etc. Examples of different RATs include 2G GERAN (GSM) radio access network, 3G UTRAN (UMTS) radio access network, 4G E-UTRAN (LTE), 5G New Radio (NR) radio access network, NG-RAN (next generation RAN) and other non-3 GPP access RATs including WiFi.

In contrast to PLMNs, non-public networks (NPN) are non-public networks that are not commonly used. The NPN may be a stand-alone non-public network (SNPN), i.e. it is operated by the NPN operator and is independent of the network functions provided by the PLMN; or the NPN may be a public network integrated NPN (public network integrated NPN, PNI-NPN), i.e. a non-public network deployed under support of the PLMN. The credential holder (credentials holder, CH) can authenticate and authorize access to the SNPN independent of the credential holder. The combination of the PLMN ID and the network identifier (network identifier, NID) identifies the SNPN.

In 5GS, a PDU session defines an association between a UE and a data network providing PDU connectivity services. PDU session establishment is a parallel procedure to the PDN connection (bearer) procedure in 4G/LTE. Each PDU session is identified by a PDU Session ID (PSI) and may include a plurality of QoS flows and QoS rules. Each PDU session may be established via a 5G access network (e.g., a 3GPP RAN or a non-3 GPP access). The network and/or UE may initiate different PDU session procedures, such as PDU session establishment, PDU session modification, and PDU session release, to manage activation (activation) and deactivation (deactivation) of the 5GS PDU session.

The UE can only establish the maximum number of PDU sessions in the PLMN or SNPN. When the number of active 5GS PDU sessions reaches the maximum number of 5GS PDU sessions of the network (PLMN or SNPN), then the UE should not send a request to establish additional PDU sessions. If the UE supports access to the SNPN using credentials from the credential holder, a solution should be sought for how to handle and maintain the maximum number of PDU sessions when the UE uses different subscriptions to access the SNPN.

Disclosure of Invention

The embodiment of the invention provides a method for processing the maximum number of protocol data unit sessions, which comprises the following steps: maintaining, by a UE, a plurality of subscriptions for accessing a SNPN, wherein the UE supports accessing the SNPN using credentials from a credential holder; selecting a first subscription to access the selected SNPN, wherein the UE maintains a first maximum number of PDU sessions associated with the first subscription for the selected SNPN; and selecting a second subscription to access the selected SNPN, wherein the UE maintains a second maximum number of PDU sessions associated with the second subscription for the selected SNPN.

The embodiment of the invention provides user equipment, which comprises the following steps: an SNPN information processing circuit that maintains a plurality of subscriptions for accessing SNPN, wherein the UE supports accessing the SNPN using credentials from a credential holder; control circuitry to select a first subscription to access the selected SNPN, wherein the UE maintains a first maximum number of PDU sessions associated with the first subscription for the selected SNPN, wherein the control circuitry further selects a second subscription to access the selected SNPN, and the UE maintains a second maximum number of PDU sessions associated with the second subscription for the selected SNPN.

By utilizing the present invention, the maximum number of PDU sessions can be better handled.

Other embodiments and advantages are described in the detailed description that follows. This summary is not intended to limit the invention. The invention is defined by the claims.

Drawings

Fig. 1 schematically illustrates a communication system with a Public Land Mobile Network (PLMN), an independent non-public network (SNPN), and a public network integrated NPN (PNI-NPN) supporting (hosting) networks with localized services and cell selection according to an embodiment of the invention.

Fig. 2 illustrates a simplified block diagram of a user equipment and a network entity according to an embodiment of the present invention.

Fig. 3A illustrates a first embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder.

Fig. 3B illustrates a second embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder.

Fig. 4 illustrates an example of NG-RAN mode that broadcasts certain information to provide access to the SNPN.

Fig. 5A illustrates an example of a SNPN-enabled UE configured with 2 SNPN subscriptions (i.e., SNPNs of 2 subscriptions in a "subscriber data list").

Fig. 5B illustrates an example of a SNPN-enabled UE configured with 2 PLMN subscriptions (i.e., 2 USIMs).

Fig. 6 illustrates network selection in an SNPN access mode with automatic and manual SNPN network selection.

Fig. 7 illustrates an embodiment in which a UE registers with a selected SNPN using a subscription selected from a plurality of SNPN or PLMN subscriptions.

Fig. 8 is a flow diagram of a method for registering with a selected SNPN and corresponding maximum number of PDU session treatments using multiple subscriptions, according to an embodiment.

Detailed Description

Reference will now be made in detail to some embodiments of the invention, examples of which are illustrated in the accompanying drawings.

Fig. 1 schematically illustrates a communication system 100 providing access to localized services having a Public Land Mobile Network (PLMN) 110, a standalone SNPN120, and a PNI-NPN/CAG 130 according to an embodiment of the invention. The PLMN network 110 includes control plane functions, user plane functions (e.g., UPF), and applications that provide various services by communicating with a plurality of UEs including the UE 101. The serving base station gNB 112 is part of the radio access network RAN 140. The RAN 140 provides radio access to the UE 101 via a RAT. Access and mobility management functions (access and mobility management function, AMF) in the PLMN 110 communicate with the gNB 112. The UE 101 can be equipped with one or more Radio Frequency (RF) transceivers.

The SNPN network 120 includes control plane functions, user plane functions (e.g., UPF), and applications that provide various services by communicating with a plurality of UEs including the UE 101. The combination of PLMN ID and NID identifies the SNPN. Serving base station gNB 122 is part of RAN 150. The RAN 150 provides radio access to the UE 101 via a RAT. The AMFs in the SNPN120 communicate with the gNB 122. The SNPN120 is operated by an NPN operator and is independent of network functions provided by the public network. The CH may authenticate and authorize access to the SNPN independent of the credential holder. The NG-RAN node providing access to the SNPN may broadcast the following information: one or more PLMN IDs, and a NID list identifying each PLMN ID of a non-public network (123) to which the NG-RAN provides access. The SNPN-enabled (SNPN-enabled) UE is configured with a PLMN ID and NID (SNPN ID) of the subscribed SNPN, and may additionally be configured with information (102) for SNPN selection (SNPN selection information or configuration), registration (in SNPN access mode) using SNPN subscription or using PLMN subscription (USIM) for SNPN-enabled UEs that access SNPN using credentials from credential holders.

PNI-NPN (CAG) network 130 includes control plane functions (which may optionally be PLMN dependent), user plane functions (which may optionally be PLMN dependent), and applications to provide various services by communicating with a plurality of UEs including UE 101. PNI-NPN () CAG) 130 is a non-public network deployed by sharing (e.g., RAN/GNB 112 and e.g., control plane functions) under the support of a PLMN (e.g., PLMN 110). A closed access group (closed access group, CAG) identifies a subscriber group that is allowed to access one or more CAG cells associated with the CAG. The CAG is used for the PNI-NPN to prevent UEs that are not allowed to access the NPN via the associated cell from automatically selecting and accessing the associated CAG cell. CAGs are identified by CAG identifiers that are unique within the range of PLMN IDs. The CAG cell broadcasts one or more CAG identifiers (113) per PLMN, and the UE is configured with CAG related configuration/information (e.g., a (enhanced) CAG information list containing a list of allowed CAGs per PLMN) (102).

A localized or localized service is a localized service, i.e., provided at a particular/limited area and/or limited in time (e.g., during a particular period of time). A localization service provider is an application provider or network operator that localizes its services and provides them to end users via a hosting network. The managed network is a network for providing access to the localized service, and can be SNPN or PNI-NPN; and the home network (home network) is a network that has subscriptions or credentials in current use of the UE. In the example of fig. 1, both the SNPN120 and the PNI-NPN (CAG) 130 may be hosted networks that provide the UE 101 with access to localized services.

The UE routing rules (UE route selection policy, urs) may include association of UE applications with DNNs or network slices for specific localized services. The urs rules may also include "routing validity criteria" (time window and/or location criteria validity conditions) with defined time/location for a particular localized service. A local access data network (local access data network, LADN) may also be used to enable UEs to access localized services.

In order to enable PNI-NPN or SNPN to provide access to localized services, a PNI-NPN or SNPN operator configures a network with information enabling a UE to access localized services according to their availability, determined in correspondence with a localized service provider, for example: (a) An identification of each localized service, such as an identification to be used in the urs rules; (b) Validity criteria/limits for each localization service, such as validity of duration and/or validity of location (area).

When the localization service in the network is completed, all UEs registered with the network are expected to be moved to other networks or other cells within the same network. The other network may be an HPLMN, VPLMN or another SNPN. The UE may cease using network resources for localized services for a number of reasons, such as: (a) localized service completion in the network; (b) the validity condition of the network selection information is no longer satisfied; (c) The user decides to stop using the localization service before the localization service is completed (e.g., the end user cannot access the localization service); (d) The effect of the network taking policy decisions is that the UE is de-registered before the localization service is completed. Validity information or restrictions or criteria or conditions (103) may be provided or configured to the UE as part of the localized service information for restricting access by the UE to the SNPN/PNI-NPN (as a hosted network) providing access to the localized service. In order to provide localized services to UEs, the UEs need to be able to discover, select and access the SNPN/PNI-NPN (as a hosted network) that provides access to the localized services. The discovery mechanism is based on providing or configuring the UE with appropriate information.

Fig. 2 illustrates a simplified block diagram of a wireless device (e.g., UE 201 and network entity 211) according to an embodiment of the present invention. The network entity 211 may be a combination of a base station and an AMF. The network entity 211 has an antenna 215 that sends and receives radio signals. A radio frequency RF transceiver module 214 coupled to the antenna receives the RF signal from the antenna 215, converts it to a baseband signal and sends it to the processor 213. The RF transceiver 214 also converts the baseband signal received from the processor 213 into an RF signal and transmits it to the antenna 215. The processor 213 processes the received baseband signal and invokes different functional modules to perform the features in the network entity 211. Memory 212 stores program instructions and data 220 for controlling the operation of network entity 211. In the example of fig. 2, network entity 211 also includes a set of control function modules and circuits 290. Registration circuit 231 handles registration and mobility procedures. Session management circuit 232 handles session management functions. The configuration and control circuit 233 provides different parameters to configure and control the UE.

Similarly, UE 201 has memory 202, processor 203, and RF transceiver module 204. The RF transceiver 204 is coupled to the antenna 205, receives RF signals from the antenna 205, converts them to baseband signals and sends them to the processor 203. The RF transceiver 204 also converts the baseband signal received from the processor 203 into an RF signal and sends it to the antenna 215. The processor 203 processes the received baseband signals and invokes various functional modules and circuits to perform the features in the UE 201. The memory 202 stores data and program instructions 210 that are executed by the processor to control the operation of the UE 201. Suitable processors include, by way of example, a special purpose processor, a digital signal processor (digital signal processor, DSP), a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a controller, a microcontroller, application specific integrated circuits (application specific integrated circuit, ASIC), field programmable gate array (field programmable gate array, FPGA) circuits, and other types of integrated circuits (integrated circuit, ICs), and/or state machines. Features of UE 201 may be implemented and configured using a processor associated with software.

The UE 201 also includes a set of functional modules and control circuitry to perform the functional tasks of the UE 201. The protocol stack 260 includes a non-access stratum (NAS) layer for communicating with an AMF entity connected to a core network, a radio resource control (radio resource control, RRC) layer for higher layer configuration and control, a packet data convergence protocol (packet data convergence protocol, PDCP)/radio link control (radio link control, RLC) layer, a medium access control (medium access control, MAC) layer, and a Physical (PHY) layer. The system modules and circuitry 270 may be implemented and configured by software, firmware, hardware, and/or combinations thereof. The functional modules and circuits, when executed by the processor via program instructions contained in the memory, cooperate to allow the UE 201 to perform the functional tasks and features of the various embodiments, networks. In one example, the system module and circuit 270 includes: a registration circuit 221 for performing registration and mobility procedures with the network; network and cell selection circuitry 222 for performing network and cell selection; PLMN/PNI-NPN (CAG)/snp information maintenance circuitry 223 to handle addition, removal, and reset of one or more PLMN/PNI-NPN (CAG)/snp information (information source may also come from signaling) in the SIM/USIM and/or in the UE (non-volatile) memory; configuration and control circuitry 224 for processing configuration and control parameters. Note that network selection and registration related information, such as HPLMN, operator controlled PLMN/SNPN selector list, user controlled PLMN/SNPN selector list, may be stored in SIM/USIM 225 and/or in UE (non-volatile) memory.

SNPN

Fig. 3A illustrates a first embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder. Fig. 3A depicts a 5G system architecture of a SNPN in which a credential holder uses an AAA server for primary (primary) authentication and authorization. AUSF and UDM in SNPN may use credentials of AAA server in CH to support primary authentication and authorization of UE. The SNPN in fig. 3A may be a subscription SNPN for the UE (i.e., the NG-RAN broadcasts the SNPN ID of the subscription SNPN). As a deployment option, the SNPN in fig. 3A may also be another SNPN than the SNPN subscribed to by the UE (i.e., none of the SNPN IDs broadcast by the NG-RAN match the SNPN IDs corresponding to the subscribed SNPNs). NSSAAF deployed in the SNPN may use CH to support primary authentication in the SNPN with credentials provided by the AAA server (as depicted), and/or NSSAAF may use network slice-specific AAA servers to support network slice-specific authentication and authorization (not depicted).

Fig. 3B illustrates a second embodiment of a 5G system architecture for accessing a SNPN using credentials from a credential holder. Fig. 3B depicts a 5G system architecture of the SNPN, where credential holders use AUSF and UDM for primary authentication and authorization and network slicing. The SNPN may support primary authentication and authorization for UEs using the CH with credentials provided by the AUSF and UDM. The credential holder may be a SNPN or PLMN. The credential holder UDM provides subscription data to the SNPN.

Fig. 4 illustrates an example of NG-RAN mode, where the NG-RAN mode broadcasts certain information to provide access to the SNPN. The CH may authenticate and authorize access to the SNPN independent of the credential holder. For a SNPN identification, the combination of PLMN ID and NID may identify the SNPN. NID supports two assignment models. Under the self-assignment model (NID-assignment model), NID is chosen by SNPN alone (and thus may not be unique) at deployment, but a different numbering space (numbering space) than the coordinated assignment NID would be used. Under the coordinated allocation model (coordinated assignment model), NID is allocated using one of two options: 1) NID is assigned such that it is globally unique, independent of the PLMN ID used; or 2) NID is assigned such that the combination of NID and PLMN ID is globally unique.

Group IDs (GINs) for network selection support two allocation models. Under the self-assignment model, GIN is selected alone and therefore may not be unique. Under the coordinated allocation model, GIN is allocated using a combination of PLMN ID and NID and using one of two options: 1) GIN is assigned such that NID is globally unique (e.g., using an IANA private enterprise number), independent of PLMN ID used; or 2) GIN is assigned such that the combination of NID and PLMN ID is globally unique.

In the example of fig. 4, NG-RAN 401 provides access to the SNPN and broadcasts the following information (410): one or more PLMN IDs, the NID list of each PLMN ID being used to identify non-public networks (e.g., SNPN1 and SNPN 2) to which the NG-RAN provides access. Optionally, the broadcasted information may further comprise the following: a human-readable network name (human-readable network name, HRNN) for each SNPN; an indication of whether each SNPN supports access using credentials from a credential holder; a list of Group IDs (GINs) supported by each SNPN for network selection (e.g., GIN 1 and GIN 2); and an indication of whether each SNPN allows a registration attempt from a UE that is not explicitly configured to select a SNPN, i.e., a UE that does not have any SNPN ID (PLMN id+nid) or GIN broadcast in the prioritized list of preferred SNPNs/GINs for CH control.

Fig. 5A illustrates an example of a SNPN-enabled UE configured with SNPN subscription information for each subscribed SNPN. In the example of fig. 5A, as shown at 510/520, the SNPN-enabled UE 501 is configured with 2 SNPN subscriptions for each subscribed SNPN: the SNPN ID (PLMN ID+NID) of the subscribed SNPN (e.g., SNPN1 in entry 1 of "subscriber data List," SNPN 2 in entry 2 of "subscriber data List"); and a subscription identifier (subscription identifie, SUPI) and credentials for each subscription SNPN. If the UE uses credentials from the credential holder to access the SNPN for each subscribed SNPN, the UE may configure: 1) A prioritized list of user-controlled preferred SNPNs (e.g., SNPN 111, SNPN112 of entry 1; SNPN 211, SNPN 212 of entry 2); 2) A prioritized list of preferred SNPNs controlled by the credential holder (e.g., SNPN 121, SNPN 122 of entry 1; SNPN 221, SNPN 222 of entry 2); and 3) a prioritized list of credential holder-controlled GINs (e.g., GIN 131, GIN 132 of entry 1; GIN 231, GIN 232 of entry 2).

Fig. 5B illustrates an example of an SNPN enabled UE configured with 2 PLMN subscriptions (i.e., 2 USIMs). For a UE supporting access to a SNPN using credentials from a credential holder and equipped with a PLMN subscription (USIM) enabled SNPN, information for SNPN selection and registration using PLMN subscription (in SNPN access mode) may be additionally configured. For example, PLMN subscription 1 is associated with information 530 for SNPN selection: 1) A prioritized list of user-controlled preferred SNPNs (e.g., SNPN 311, SNPN 312); 2) A prioritized list of preferred SNPNs controlled by the credential holder (e.g., SNPN 321, SNPN 322); and 3) a prioritized list of GINs controlled by the credential holder (e.g., GIN 331, GIN 332). Similarly, PLMN subscription 2 is associated with information 540 for SNPN selection: 1) A prioritized list of user-controlled preferred SNPNs (e.g., SNPN 411, SNPN 412); 2) A prioritized list of preferred SNPNs controlled by the credential holder (e.g., SNPN 421, SNPN 422); and 3) a prioritized list of credential holder-controlled GINs (e.g., GIN 431, GIN 432).

The subscription of the SNPN is identified by the SUPI, which contains a network specific identifier in the form of a network access identifier (network access identifier, NAI). The domain (realm) portion of the NAI may include the NID of the SNPN or be identified by the SUPI containing the IMSI. For a SNPN enabled UE with a SNPN subscription, a roaming bootstrap (steering of roaming, soR) procedure may be used by the CH to update the prioritized list of preferred SNPNs/GINs controlled by the credential holder. For a SNPN enabled UE with PLMN subscription, the SoR procedure may be used by the CH to update the priority list of preferred SNPNs/GINs controlled by the credential holder. When the credential holder updates the UE with a prioritized list of preferred SNPNs and GINs controlled by the credential holder, the UE may again perform SNPN selection, e.g., may potentially select a higher priority SNPN.

Fig. 6 illustrates network selection in an SNPN access mode with automatic and manual SNPN network selection. The SNPN-enabled UE 601 supports access to SNPN (in SNPN access mode). When the UE is set to operate in the SNPN access mode, the UE selects only the SNPN and registers with the SNPN. When the UE is set to operate in the SNPN access mode, the UE does not perform a normal PLMN selection procedure. There are two SNPN network selection procedures: an automatic SNPN network selection process and a manual SNPN network selection process.

Under automatic SNPN network selection, the UE selects and attempts to register on available and allowable SNPNs in the following order: 1) The SNPN (if available) or equivalent SNPN (if available) that the UE last registered; 2) The subscribed SNPN, which is identified by SNPN ID (PLMN ID+NID), the UE has its SUPI and credentials; 3) If the UE supports access to the SNPN using credentials from the credential holder, the UE selects and attempts to continue with registration on available and allowable SNPNs that broadcast indications that support access using credentials from the credential holder in the following order: a) The SNPN (in order of priority) in the priority list of user-controlled preferred SNPN; b) The SNPN (in order of priority) in the priority list of preferred SNPN controlled by the credential holder; c) Additionally broadcasting the SNPN (in order of priority) of the GINs contained in the priority list of the preferred GINs controlled by the credential holder; and 4) additionally broadcasting an indicated SNPN allowing registration attempts from a UE not explicitly configured to select SNPN, i.e. the broadcasted SNPN ID or GIN is not present in the priority list of preferred SNPN/GINs controlled by the credential holder in the UE.

In the example of fig. 6, the UE 601 registers with the SNPN 100, the subscribed SNPN is SNPN1, and has three credential lists. The preferential list of the preferential SNPN controlled by the user comprises SNPN 111 and SNPN 112; the prioritized list of preferred SNPNs controlled by the credential holder includes SNPN 121, SNPN 122; the prioritized list of credential holders controlled GINs includes GINs 131, 132. There is a list of available SNPN/GINs (broadcast by one or more NG-RANs) for the current UE location, e.g., SNPN 100, SNPN1, SNPN 111, SNPN112, SNPN 121, SNPN 300/GIN 131. The UE 601 selects and attempts to register with the SNPN in the following preference/priority order: SNPN 100, SNPN1, SNPN 111, SNPN112, SNPN 121, and SNPN 300 of GIN 131 are also broadcast.

Under manual network selection, a UE operating in an SNPN access mode provides the user with a list of SNPNs (each identified by PLMN ID and NID) and the associated human-readable network names of available SNPNs for which the UE has corresponding SUPI and credentials, if available. If the UE supports access to the SNPN using credentials from the credential holder, the UE also presents an available SNPN broadcasting an indication of "support for access using credentials from the credential holder" and a human-readable name associated with the SNPN, if available. When the UE performs initial registration with the SNPN, the UE should indicate to the NG-RAN the selected PLMN ID and NID broadcast by the selected SNPN. The NG-RAN should inform the AMF of the selected PLMN ID and NID.

If the UE performs a registration or service request procedure in the SNPN identified by the PLMN ID and the self-assigned NID without a subscription to the UE, the AMF should reject the UE with an appropriate cause code to temporarily prevent the UE from automatically selecting and registering with the same SNPN. If the UE performs a registration or service request procedure in the SNPN identified by the PLMN ID and the coordination assignment NID without a subscription to the UE, the AMF should reject the UE with an appropriate cause code to permanently prevent the UE from automatically selecting and registering with the same SNPN. If the UE performs registration in the SNPN using credentials from the credential holder, but the UE is not authorized to access that particular SNPN, the UDM may reject the UE, which results in the AMF rejecting the registration request from the UE with the appropriate cause code to prevent the UE from selecting the same SNPN and registering using credentials from the credential holder. To prevent authorized UEs from accessing the SNPN in the event of network congestion/overload, access control information is unified by the SNPN configuration (i.e., as part of the subscription information the UE has for a given SNPN) and provided to the UE.

Maximum number of PDU sessions

The SNPN-enabled UE may configure SNPN subscription information for each subscribed SNPN. If the UE supports access to each subscribed SNPN using credentials from the credential holder, the SNPN subscription includes, for each subscribed SNPN, the SNPN ID of the subscribed SNPN, the credentials, and the UE configuration for SNPN selection, e.g., a prioritized list of preferred SNPNs controlled by the credential holder. Furthermore, for a UE supporting access to a SNPN using credentials from a credential holder and equipped with a PLMN subscription (USIM) enabled SNPN, information for SNPN selection and registration using the PLMN subscription (USIM) may be additionally configured (in the SNPN access mode).

When the SNPN-enabled UE is set to operate in the SNPN access mode, the UE selects only SNPN and registers with the SNPN. There are two SNPN network selection procedures: an automatic SNPN network selection process and a manual SNPN network selection process. Under automatic SNPN network selection, the UE selects and attempts to register on available and allowable SNPNs in a predefined order. Under manual network selection, a UE operating in an SNPN access mode provides a list of SNPNs (each identified by a PLMN ID and NID) to the user along with the relevant human-readable network names (if available) of available SNPNs for which the UE has corresponding SUPI and credentials. If the UE supports access to SNPN using credentials from the credential holder, the UE also presents an available SNPN broadcasting an indication of "support for access using credentials from the credential holder".

In 5GS, a PDU session defines an association between a UE and a data network providing PDU connectivity services. Each PDU session may be established via a 5G access network (e.g., a 3GPP RAN or a non-3 GPP access). The network and/or UE may initiate different PDU session procedures, such as PDU session establishment, PDU session modification, and PDU session release, to manage activation and deactivation of the 5GS PDU session. The UE can only maintain the maximum number of PDU sessions in the PLMN or SNPN. When the number of active 5GS PDU sessions reaches the maximum number of 5GS PDU sessions of the network (PLMN or SNPN), the UE should not send a request to establish additional PDU sessions.

If the UE supports access to the SNPN using credentials from the credential holder, the UE also needs to select an appropriate subscription (subscriber identifier + credentials) to access/register to the selected SNPN during the SNPN selection process. This is because the UE may have multiple subscriptions for access/registration to the selected SNPN. The subscription may be a SNPN subscription or a PLMN subscription. In one embodiment, a method of handling a maximum number of PDU sessions per SNPN per subscription is presented. If the UE has multiple subscriptions accessing the selected SNPN, the UE maintains the maximum number of PDU sessions of the selected SNPN independently for each selected subscription. If the UE selects the first subscription to access the selected SNPN, the UE should not send a PDU session setup request message if the number of active PDU sessions has reached the maximum number of PDU sessions associated with the first subscription (e.g., the first number) of the selected SNPN. Similarly, if the UE selects the second subscription to access the selected SNPN, the UE should not send a PDU session setup request message if the number of active PDU sessions has reached the maximum number of PDU sessions (e.g., the second number) of the selected SNPN associated with the second subscription.

Fig. 7 illustrates an embodiment in which a UE registers with a selected SNPN using a subscription selected from a plurality of SNPN or PLMN subscriptions. In the example of fig. 7, the UE 701 is configured with SNPN subscriptions, and the subscriber data list includes two entries (i.e., two SNPN subscriptions): a first entry (entry 1) of the SNPN1 for subscription with a prioritized list of user-controlled preferred SNPNs (SNPN 111, SNPN 112) and a prioritized list of credential holder-controlled preferred SNPNs (SNPN 121), said list belonging to the SNPN selection parameters of the first entry (entry 1) stored in the UE; and a second entry (entry 2) for SNPN 2 having a prioritized list of user-controlled preferred SNPNs (SNPN 111, SNPN 112) and a prioritized list of credential holder-controlled preferred SNPNs (SNPN 121), the list belonging to the SNPN selection parameters of the second entry (entry 2) stored in the UE.

The UE 701 is also equipped with PLMN subscription (USIM) and is configured with information of SNPN selection (SNPN selection parameters) in the SNPN access mode and registration using PLMN subscription (USIM). PLMN subscription 1 (USIM 1) is associated with the SNPN selection information, wherein the SNPN selection information comprises a prioritized list of user-controlled preferred SNPNs (SNPN 111, SNPN 112) and a prioritized list of credential holder-controlled preferred SNPNs (SNPN 121), which belong to the SNPN selection parameters of USIM1 stored in the UE (for access in SNPN). PLMN subscription 2 (USIM 2) is associated with the SNPN selection information, wherein the SNPN selection information comprises a prioritized list of user-controlled preferred SNPNs (SNPN 111, SNPN 112) and a prioritized list of credential holder-controlled preferred SNPNs (SNPN 121), which belong to the SNPN selection parameters of USIM2 stored in the UE (for access in SNPN).

In a first example, the UE selects entry 1 of the "subscriber data list" to access/register the SNPN 121. During the PDU session establishment procedure requested by the UE, the 5GSM sub-layer in the UE receives an indication that the 5GSM message was not forwarded due to the maximum number of PDU sessions for which the SNPN has been reached. The UE determines the maximum number of PDU sessions of the SNPN as the number of active PDU sessions it has (e.g., 3) and associates the determined maximum number of PDU sessions with entry 1 of the selected "subscriber data list".

In a second example, the UE selects entry 2 of the "subscriber data list" to access/register the SNPN 121. During the PDU session establishment procedure requested by the UE, the 5GSM sub-layer in the UE receives an indication that the 5GSM message was not forwarded due to the maximum number of PDU sessions for which the SNPN has been reached. The UE determines the maximum number of PDU sessions of the SNPN as the number of active PDU sessions it has (e.g., 4) and associates the determined maximum number of PDU sessions with entry 2 of the selected "subscriber data list".

In a third example, the UE selects PLMN subscription 1 (USIM 1) to access/register the SNPN 121. During the PDU session establishment procedure requested by the UE, the 5GSM sub-layer in the UE receives an indication that the 5GSM message was not forwarded due to the maximum number of PDU sessions for which the SNPN has been reached. The UE determines the maximum number of PDU sessions of the SNPN as the number of active PDU sessions it has (e.g., 5) and associates the determined maximum number of PDU sessions with the selected PLMN subscription 1 (USIM 1).

In a fourth example, the UE selects PLMN subscription 2 (USIM 2) to access/register the SNPN 121. During the PDU session establishment procedure requested by the UE, the 5GSM sub-layer in the UE receives an indication that the 5GSM message was not forwarded due to the maximum number of PDU sessions for which the SNPN has been reached. The UE determines the maximum number of PDU sessions of the SNPN as the number of active PDU sessions it has (e.g., 6) and associates the determined maximum number of PDU sessions with the selected PLMN subscription 2 (USIM 2).

Fig. 8 is a flow diagram of a method for accessing/registering with a selected SNPN and a corresponding maximum number of PDU session treatments using multiple subscriptions, according to an embodiment. In step 801, the UE maintains a plurality of subscriptions, such as zero, one or more SNPN subscriptions ("subscriber data list") and/or zero, one or more PLMN subscriptions (USIMs), for accessing SNPNs. In step 802, the UE selects a first subscription to register with a first SNPN (e.g., SNPN 121). During the PDU session establishment procedure requested by the UE, the 5GSM sub-layer in the UE receives an indication that the 5GSM message was not forwarded due to the maximum number of PDU sessions for which the SNPN has been reached. The UE determines the maximum number of PDU sessions of the first SNPN as the number of active PDU sessions it has (first number) and associates the determined maximum number of PDU sessions with the first subscription. In step 803, the UE selects a second subscription to register with the first SNPN (e.g., SNPN 121). During the PDU session establishment procedure requested by the UE, the 5GSM sub-layer in the UE receives an indication that the 5GSM message was not forwarded due to the maximum number of PDU sessions for which the SNPN has been reached. The UE determines the maximum number of PDU sessions of the first SNPN as the number of active PDU sessions it has (second number) and associates the determined maximum number of PDU sessions with the second subscription.

In step 804, the UE selects to return to the first subscription to access/register the first SNPN (e.g., SNPN 121). If the maximum number of PDU sessions, which is the number of active PDU sessions it has, is equal to the first number, and if the upper layer of the UE requests a connection to the DNN, the UE should not send a PDU session establishment request message. In step 805, the UE selects to return to the second subscription to access/register the first SNPN (e.g., SNPN 121). If the maximum number of PDU sessions, which is the number of active PDU sessions it has, is equal to the second number, and if the upper layer of the UE requests a connection to the DNN, the UE should not send a PDU session establishment request message. In an embodiment, the first subscription or the second subscription is an SNPN subscription and is contained in an entry of a subscriber data list of the SNPN. In another embodiment, the first subscription or the second subscription is a PLMN subscription of a universal subscription identity module (universal subscription identification module, USIM).

In one embodiment, a storage medium (e.g., a computer-readable storage medium) stores a program that, when executed, causes a UE to perform embodiments of the present invention.

Although the present invention has been described in connection with certain specific embodiments for instructional purposes, the present invention is not limited thereto. Accordingly, various modifications, adaptations, and combinations of the various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.

Claims (19)

1. A method of handling a maximum number of protocol data unit sessions, comprising:

maintaining, by a user equipment, UE, a plurality of subscriptions for accessing independent non-public networks, SNPNs, wherein the UE supports accessing the SNPNs using credentials from a credential holder;

selecting a first subscription to access the selected SNPN, wherein the UE maintains a first maximum number of protocol data unit PDU sessions associated with the first subscription for the selected SNPN; and

a second subscription is selected to access the selected SNPN, wherein the UE maintains a second maximum number of PDU sessions associated with the second subscription for the selected SNPN.

2. The method of handling a maximum number of protocol data unit sessions according to claim 1, wherein the selected SNPN is included in a user controlled SNPN list for a UE configuration for SNPN selection.

3. The method of handling a maximum number of protocol data unit sessions according to claim 1, wherein the selected SNPN is included in a list of ppns controlled by a credential holder for UE configuration for SNPN selection.

4. The method of handling a maximum number of protocol data unit sessions according to claim 1, wherein the first subscription or the second subscription is a SNPN subscription and is contained in an entry of a subscriber data list of a SNPN.

5. The method of handling a maximum number of protocol data unit sessions according to claim 1, wherein the first subscription or the second subscription is a public land mobile network, PLMN, subscription of a universal subscription identity module, USIM.

6. The method of handling a maximum number of protocol data unit sessions according to claim 1, wherein the UE registers with the selected SNPN using the first subscription, and wherein the UE receives an indication of: during the PDU session establishment procedure, the number of active PDU sessions has reached the first maximum number of PDU sessions for the selected SNPN.

7. The method of processing a maximum number of protocol data unit sessions of claim 6, wherein the UE refrains from sending a PDU session establishment request message when the number of active PDU sessions has reached the first maximum number of PDU sessions.

8. The method of handling a maximum number of protocol data unit sessions according to claim 1, wherein the UE registers with the selected SNPN using the second subscription, and wherein the UE receives an indication of: during the PDU session establishment procedure, the number of active PDU sessions has reached a second maximum number of PDU sessions for the selected SNPN.

9. The method of handling a maximum number of protocol data unit sessions according to claim 8, wherein the UE refrains from sending a PDU session establishment request message when the number of active PDU sessions has reached a second maximum number of PDU sessions.

10. A user equipment, UE, comprising:

an independent non-public network, SNPN, information processing circuit that maintains a plurality of subscriptions for accessing SNPNs, wherein the UE supports accessing the SNPNs using credentials from a credential holder; and

control circuitry to select a first subscription to access the selected SNPN, wherein the UE maintains a first maximum number of protocol data unit, PDU, sessions associated with the first subscription for the selected SNPN, wherein the control circuitry further selects a second subscription to access the selected SNPN, and the UE maintains a second maximum number of PDU sessions associated with the second subscription for the selected SNPN.

11. The UE of claim 10, wherein the selected SNPN is included in a user-controlled SNPN list for a UE configuration for SNPN selection.

12. The UE of claim 10, wherein the selected SNPN is included in a list of SNPNs controlled by a credential holder for UE configuration of the SNPN selection.

13. The UE of claim 10, wherein the first subscription or the second subscription is an SNPN subscription and is included in an entry of a subscriber data list of an SNPN.

14. The UE of claim 10, wherein the first subscription or the second subscription is a public land mobile network, PLMN, subscription of a universal subscription identity module, USIM.

15. The UE of claim 10, wherein the UE registers with the selected SNPN using the first subscription, and wherein the UE receives an indication of: during the PDU session establishment procedure, the number of active PDU sessions has reached the first maximum number of PDU sessions for the selected SNPN.

16. The UE of claim 15, wherein the UE refrains from sending a PDU session establishment request message when the number of active PDU sessions has reached the first maximum number of PDU sessions.

17. The UE of claim 10, wherein the UE registers with the selected SNPN using the second subscription, and wherein the UE receives an indication of: during the PDU session establishment procedure, the number of active PDU sessions has reached a second maximum number of PDU sessions for the selected SNPN.

18. The UE of claim 17, wherein the UE refrains from sending a PDU session establishment request message when the number of active PDU sessions has reached the second maximum number of PDU sessions.

19. A storage medium storing a program which, when executed, causes a user equipment to perform the steps of the method of handling a maximum number of protocol data unit sessions of any of claims 1-9.