WO2023184462A1

WO2023184462A1 - Dedicated mbr configuration for network slice in communication networks

Info

Publication number: WO2023184462A1
Application number: PCT/CN2022/084737
Authority: WO
Inventors: Xiaojian YAN; Jinguo Zhu
Original assignee: Zte Corporation
Priority date: 2022-04-01
Filing date: 2022-04-01
Publication date: 2023-10-05

Abstract

This disclosure generally relates to network slicing in communication networks. Performed by a first NE, the method includes: transmitting a first message to a second NE, the first message comprising a first network slice configuration of a first home network slice subscribed by a UE in a home network of the UE, so that the second NE is configured to configure a first network slice service corresponding to the first home network slice based on the first network slice configuration, wherein the first network slice configuration comprises: a mapping between the first home network slice and a first visited network slice, the first visited network slice being assigned to the UE to serve the first home network slice; a first MBR information which applies to the first home network slice, and does not apply to other home network slices of the UE.

Description

DEDICATED MBR CONFIGURATION FOR NETWORK SLICE IN COMMUNICATION NETWORKS

TECHNICAL FIELD

This disclosure is directed to wireless communication, and in particular, to network slicing in communication networks.

BACKGROUND

Network slicing is a critical feature in a communication network, e.g., a fifth generation (5G) wireless network. Using network slicing, multiple unique virtual networks may be created under a common infrastructure. Each slice may have its own architecture and configuration, in order to meet a specific use case. Each slice may have a specific Quality of Service (QoS) requirement which in turn requires different network resources such as bandwidth. It is important to effectively manage the network slices in both the home network of a User Equipment (UE) and the visited network of the UE.

SUMMARY

This disclosure relates to network slicing in communication networks, and in particular, to providing dedicated Maximum Bit Rate (MBR) configuration for a network slice when the UE is in a visited network.

In one embodiment, the present disclosure describes a method for wireless communication. Performed by first Network Element (NE) in a wireless network, the method includes: transmitting a first message to a second NE in the wireless network, the first message comprising a first network slice configuration of a first home network slice subscribed by a User Equipment (UE) in a home network of the UE, wherein the first network slice configuration comprises: a mapping between the first home network slice and a first visited network slice, the first visited network slice being assigned to the UE to serve the first home network slice when the UE is in a visited network of the UE; and a first Maximum Bit Rate (MBR) information which applies to the first home network slice, and does not apply to other home network slices of the UE.

In another embodiment, the present disclosure describes a method for wireless communication. Performed by a first NE in a wireless network, the method includes: receiving a first message from a second NE in the wireless network, the first message comprising a first network slice configuration of a first home network slice subscribed by a UE in a home network of the UE, wherein the first network slice configuration comprises: a mapping between the first home network slice and a first visited network slice, the first visited network slice being assigned to the UE to serve the first home network slice when the UE is in a visited network of the UE; and a first MBR information which applies to the first home network slice, and does not apply to other home network slices of the UE.

In another embodiment, a network element or wireless device comprising a processor and a memory is disclosed. The processor may be configured to read computer code from the memory to implement any of the methods above.

In yet another embodiment, a computer program product comprising a non-transitory computer-readable program medium with computer code stored thereupon is disclosed. The computer code, when executed by a processor, may cause the processor to implement any one of the methods above.

The above embodiments and other aspects and alternatives of their implementations are explained in greater detail in the drawings, the descriptions, and the claims below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary communication network including various terminal devices, a carrier network, data network, and service applications.

FIG. 2 shows exemplary network functions or network nodes in a communication network.

FIG. 3 shows exemplary network functions or network nodes in a wireless communication network.

FIG. 4 show an example of electronic device to implement a network element.

FIG. 5-8 shows various exemplary methods and message flows for sending MBR configuration from AMF to RAN.

FIG. 9 shows an exemplary method and message flow for sending MBR configuration from a first RAN to a second RAN.

FIG. 10 shows an exemplary method and message flow for sending MBR configuration from source AMF to target AMF, and from target AMF to RAN.

DETAILED DESCRIPTION

An exemplary communication network, shown as 100 in FIG. 1, may include

terminal devices

110 and 112, a carrier network 102, various service applications 140, and other data networks 150. The carrier network 102, for example, may include access networks 120 and a core network 130. The carrier network 102 may be configured to transmit voice, data, and other information (collectively referred to as data traffic) among

terminal devices

110 and 112, between the

terminal devices

110 and 112 and the service applications 140, or between the

terminal devices

110 and 112 and the other data networks 150. Communication sessions and corresponding data paths may be established and configured for such data transmission. The Access networks 120 may be configured to provide

terminal devices

110 and 112 network access to the core network 130. The Access network 120 may, for example, support wireless access via radio resources, or wireline access. The core network 130 may include various network nodes or network functions configured to control the communication sessions and perform network access management and data traffic routing. The service applications 140 may be hosted by various application servers that are accessible by the

terminal devices

110 and 112 through the core network 130 of the carrier network 102. A service application 140 may be deployed as a data network outside of the core network 130. Likewise, the other data networks 150 may be accessible by the

terminal devices

110 and 112 through the core network 130 and may appear as either data destination or data source of a particular communication session instantiated in the carrier network 102.

The core network 130 of FIG. 1 may include various network nodes or functions geographically distributed and interconnected to provide network coverage of a service region of the carrier network 102. These network nodes or functions may be implemented as dedicated hardware network elements. Alternatively, these network nodes or functions may be virtualized and implemented as virtual machines or as software entities. A network node may each be configured with one or more types of network functions. These network nodes or network functions may collectively provide the provisioning and routing functionalities of the core network 130. The term “network nodes” and “network functions” are used interchangeably in this disclosure.

FIG. 2 further shows an exemplary division of network functions in the core network 130 of a communication network 200. While only single instances of network nodes or functions are illustrated in FIG. 2, those having ordinary skill in the art readily understand that each of these network nodes may be instantiated as multiple instances of network nodes that are distributed throughout the core network 130. As shown in FIG. 2, the core network 130 may include but is not limited to network nodes such as access management network node (AMNN) 230, authentication network node (AUNN) 260, network data management network node (NDMNN) 270, session management network node (SMNN) 240, data routing network node (DRNN) 250, policy control network node (PCNN) 220, and application data management network node (ADMNN) 210. Exemplary signaling and data exchange between the various types of network nodes through various communication interfaces are indicated by the various solid connection lines in FIG. 2. Such signaling and data exchange may be carried by signaling or data messages following predetermined formats or protocols.

The implementations described above in FIGs. 1 and 2 may be applied to both wireless and wireline communication systems. FIG. 3 illustrates an exemplary cellular wireless communication network 300 based on the general implementation of the communication network 200 of FIG. 2. FIG. 3 shows that the wireless communication network 300 may include user equipment (UE) 310 (functioning as the terminal device 110 of FIG. 2) , radio access network (RAN) 320 (functioning as the access network 120 of FIG. 2) , data network (DN) 150, and core network 130 including access management function (AMF) 330 (functioning as the AMNN 230 of FIG. 2) , session management function (SMF) 340 (functioning as the SMNN 240 of FIG. 2) , application function (AF) 390 (functioning as the ADMNN 210 of FIG. 2) , user plane function (UPF) 350 (functioning as the DRNN 250 of FIG. 2) , policy control function 322 (functioning as the PCNN 220 of FIG. 2) , authentication server function (AUSF) 360 (functioning as the AUNN 260 of FIG. 2) , and universal data management (UDM) function 370 (functioning as the UDMNN 270 of FIG. 2) . Again, while only single instances for some network functions or nodes of the wireless communication network 300 (the core network 130 in particular) are illustrated in FIG. 3, those of ordinary skill in the art readily understand that each of these network nodes or functions may have multiple instances that are distributed throughout the wireless communication network 300. While the AF 390 is depicted as part of the core network 130 in FIG. 3, they may be considered as associated with particular service applications 140 and may be considered as being outside of the core network 140.

In FIG. 3, the UE 310 may be implemented as various types of mobile devices that are configured to access the core network 130 via the RAN 320. The UE 310 may include but is not limited to mobile phones, laptop computers, tablets, Internet-Of-Things (IoT) devices, distributed sensor network nodes, wearable devices, and the like. The UE may also be Multi-access Edge Computing (MEC) capable UE that supports edge computing. The RAN 320 for example, may include a plurality of radio base stations distributed throughout the service areas of the carrier network. The communication between the UE 310 and the RAN 320 may be carried in over-the-air (OTA) radio interfaces as indicated by 311 in FIG. 3.

Continuing with FIG. 3, the UDM 370 may form a permanent storage or database for user contract and subscription data. The UDM may further include an authentication credential repository and processing function (ARPF, as indicated in 370 of FIG. 3) for storage of long-term security credentials for user authentication, and for using such long-term security credentials as input to perform computation of encryption keys as described in more detail below. To prevent unauthorized exposure of UDM/ARPF data, the UDM/ARPF 370 may be located in a secure network environment of a network operator or a third-party.

The AMF/SEAF 330 may communicate with the RAN 320, the SMF 340, the AUSF 360, the UDM/ARPF 370, and the Policy Control Function (PCF) 322 via communication interfaces indicated by the various solid lines connecting these network nodes or functions. The AMF/SEAF 330 may be responsible for UE to non-access stratum (NAS) signaling management, and for provisioning registration and access of the UE 310 to the core network 130 as well as allocation of SMF 340 to support communication need of a particular UE. The AMF/SEAF 330 may be further responsible for UE mobility management. The AMF may also include a security anchor function (SEAF, as indicated in 330 of FIG. 3) that, as described in more detail below, and interacts with AUSF 360 and UE 310 for user authentication and management of various levels of encryption/decryption keys. The AUSF 360 may terminate user registration/authentication/key generation requests from the AMF/SEAF 330 and interact with the UDM/ARPF 370 for completing such user registration/authentication/key generation.

The SMF 340 may be allocated by the AMF/SEAF 330 for a particular communication session instantiated in the wireless communication network 300. The SMF 340 may be responsible for allocating UPF 350 to support the communication session and data flows therein in a user data plane and for provisioning/regulating the allocated UPF 350 (e.g., for formulating packet detection and forwarding rules for the allocated UPF 350) . Alternative to being allocated by the SMF 340, the UPF 350 may be allocated by the AMF/SEAF 330 for the particular communication session and data flows. The UPF 350 allocated and provisioned by the SMF 340 and AMF/SEAF 330 may be responsible for data routing and forwarding and for reporting network usage by the particular communication session. For example, the UPF 350 may be responsible for routing end-end data flows between UE 310 and the DN 150, between UE 310 and the service applications 140. The DN 150 and the service applications 140 may include but are not limited to data network and services provided by the operator of the wireless communication network 300 or by third-party data network and service providers.

The PCF 322 may be responsible for managing and providing various levels of policies and rules applicable to a communication session associated with the UE 310 to the AMF/SEAF 330 and SMF 340. As such, the AMF/SEAF 330, for example, may assign SMF 340 for the communication session according to policies and rules associated with the UE 310 and obtained from the PCF 322. Likewise, the SMF 340 may allocate UPF 350 to handle data routing and forwarding of the communication session according to policies and rules obtained from the PCF 322.

Network identity and data security in the wireless communication network 300 of FIG. 3 may be managed via user authentication processes provided by the AMF/SEAF 330, the AUSF 360, and the UDM/ARPF 370. In particularly, the UE 310 may first communicate with AMF/SEAF 330 for network registration and may then be authenticated by the AUSF 360 according to user contract and subscription data in the UDM/ARPF 370. Communication sessions established for the UE 310 after user authentication to the wireless communication network 300 may then be protected by the various levels of encryption/decryption keys. The generation and management of the various keys may be orchestrated by the AUSF 360 and other network functions in the communication network 300.

While FIGs. 1-3 and the various exemplary implementations described below are based on cellular wireless communication networks, the scope of this disclosure is not so limited and the underlying principles are applicable to other types of wireless and wireline communication networks.

FIG. 4 shows an example of electronic device 400 to implement a network element (or network node, network device, network function) in the wireless communication networks. The network element may include core network element, access network element, etc. The electronic device 400 may include network interface circuitry 409 to communicate with other network elements. The network interface circuitry 409 may include optical or wireline interconnects, Ethernet, and/or other data transmission mediums/protocols. The electronic device 400 may optionally include an input/output (I/O) interface 406 to communicate with an operator or the like.

The electronic device 400 may also include system circuitry 404. System circuitry 404 may include processor (s) 421 and/or memory 422. Memory 422 may include an operating system 424, instructions 426, and parameters 428. Instructions 426 may be configured for the one or more of the processors 421 to perform the functions of the network element. The parameters 428 may include parameters to support execution of the instructions 426. For example, parameters may include network protocol settings, bandwidth parameters, radio frequency mapping assignments, and/or other parameters.

The example electronic device 400 may optionally include radio transmitting/receiving (Tx/Rx) circuitry 408 to transmit/receive communication with UEs and/or other network elements. The electronic device 400 with the Tx/Rx circuitry 408 may be configured as a base station which may provide radio access functionality.

Network Slicing

One important feature of a wireless network such as a 5G network is network slicing. Under network slicing, various resources in the network, such as computing resource, storage resource, and bandwidth resource, are divided to create a set of isolated virtual networks. Each virtual network may be considered as a network slice (or slice) . Each slice may serve a specific user application and may be allocated with customized resources to meet the specific need of the user application. One network slice may be created or instantiated isolated from other network slices.

A UE may subscribe to multiple network slices in a home network (also referred to as Home Public Land Mobile Network (HPLMN) ) . When the UE is served in the home network, each network slice may be referred to as a home network slice (or referred to as home slice) . For example, the UE may subscribe to a first slice which serves its Machine Type Communication (MTC) application. The UE may also subscribe to a second slice which serves its enhanced Mobile Broadband (eMBB) application. In this case, the first slice and the second slice may be configured with different network parameters so each has different characteristics. The network parameters may include a Maximum Bit Rate (MBR) . The second slice may be configured with a larger MBR than the first slice as eMBB generally requires higher bandwidth. When the UE subscribes to these slices in the home network, the home network may assign a particular MBR for each slice. The assigned MBR will ensure the slice meets its specific service requirement, yet preserve network resources by limiting the maximum bit rate for the slice. As an example, the MBR assigned to the first slice may be 10 Mbps (10 megabits/second) , whereas the MBR assigned to the second slice may be 20 Mbps.

In some example implementations, when the UE invokes (or requests) a network slice service, a Protocol Data Unit (PDU) session may need to be established corresponding to the network slice. Accordingly, the PDU session may be configured based on the MBR assigned to the network slice. The maximum bit rate that may be assigned to the PDU session may not exceed the MBR assigned to the network slice. For example, if the MBR assigned to the network slice is 10 Mbps, then the maximum bit rate of the PDU session may not exceed 10 Mbps.

In some other example implementations, multiple PDU sessions may be established corresponding to a same network slice. In this case, the sum of the maximum bit rate allocated to these PDU sessions may not exceed the MBR assigned to the network slice. As an example, the network slice is configured with an MBR of 10 Mbps. A first PDU session corresponding to this network slice is created with a maximum bit rate of 5 Mbps. Subsequently, a second PDU session with a desired maximum bit rate equals to 8 Mbps needs to be created. In this case, as the total maximum bit rate for the 2 PDU sessions is 13 Mbps and exceeds the MBR of the network slice, the RAN may choose to deny the creation of the second PDU session, or create the second PDU session with a reduced maximum bit rate such as 5 Mbps, to ensure the total maximum bit rate of these two PDU sessions does not exceed the MBR of the network slice. Therefore, the MBR of the corresponding network slice may need to be referenced and checked before creating, establishing, or activating a PDU session. Additionally, for an established PDU session, its QoS characteristics or requirement may be updated on the fly, which may trigger an update on the maximum bit rate that needs to be assigned to the PDU session. In this case, the MBR of the corresponding network slice may also need to be checked, to ensure that the network slice is able to support the updated maximum bit rate of the PDU session. Therefore, network elements, such as a RAN node, may need to utilize the MBR information to manage a PDU session.

The UE may roam to a visited network (also referred to as Visited Public Land Mobile Network (VPLMN) ) . Similarly, the visited network may also support network slicing. The UE may receive seamless network slicing service, if the home network and the visited network share a unified network slicing configuration. However, often time the visited network may have a different network slicing configuration compared with the home network. For example, the visited network may not support certain network slices; or the visited network may have fewer slices than the home network. For another example, the granularity of the network slice is different. In this case, one visited network slice (or referred to as visitor slice) may serve multiple home slices. For example, visitor slice 1 may serve both

home slices

1 and 2. That is, there is a mapping relationship between a home slice and a visitor slice. Home slice 1 is mapped to visitor slice 1 (to form a pair as home slice 1 + visitor slice 1) . Meanwhile, home slice 2 is also mapped to visitor slice 1 (to form a different pair: home slice 1 + visitor slice 2) . In this disclosure, for the purpose of easy description, a slice number may be used for identifying a network slice. The identification of a network slice, however, may use other formats, such as Single Network Slice Selection Assistance Information (S-NSSAI) . For example, a UE may subscribe to a list of S-NSSAIs which represents a list of network slices.

In the visited network, the UE may be served by an Access Network (AN) . The access network may include a Radio Access Network (RAN) , or a wireline Access Network. In this disclosure, the notation (R) AN is used to generally refer to an access network, whether it’s wireless or wireline. In this disclosure, the RAN may be used for exemplary purpose, and the same underline principle also applies to a wireline Access Network.

When the UE invokes network slice service in the visited network, the RAN is involved in the network procedure (s) to, for example, establish or create a PDU session corresponding to the network slice service. In doing so, the RAN needs to have the MBR information of the network slice. In current practice, the AMF (or another node or function entity) of the visited network may inform the RAN about the MBR information. The informed MBR information only applies to the visitor slice level. For example, home slice 1 (with MBR = 10 Mbps in home network) and home slice 2 (with MBR = 20 Mbps in home network) are both served by visitor slice 1. The AMF may inform the MBR information for visitor slice 1 to the RAN. The resolution of the MBR information only goes to the visitor slice level. In one implementation, MBR of visitor slice 1 may be an aggregation of MBRs of

home slices

1 and 2. Therefore, the MBR for visitor slice 1 is set to be 30 Mbps. In another implementation, the MBR of visitor slice 1 may be chosen as max (home slice 1 MBR, home slice 2 MBR) , where “max” denotes the operation to select maximum. In this case, the MBR for visitor slice 1 may be 20 Mbps. Referring to Table 1 below for an illustration of MBR assignment in a visited network.

Table 1: Shared MBR Assignment

Home Slice	Assigned Visitor Slice	Shared MBR
1 (MBR = 10Mbps)	1	30 Mbps (shared by home slices 1 and 2)

2 (MBR = 20Mbps)

1

As shown in Table 1, the current practice uses a shared MBR assignment scheme, in which the MBR assignment only goes to the visitor slice level. The assigned MBR is shared by

home slices

1 and 2. There may be a potential issue in this scheme. For example, when the UE first invokes service based on home slice 1, the visited network will serve the request using visitor slice 1 (as home slice 1 is mapped to visitor slice 1) . Since the MBR assignment in Table 1 does not separately specify the MBR information for home slice 1, the RAN may allocate an MBR with 20 Mbps to this request (e.g., 20 Mbps is assigned to home slice 1) . When the UE subsequently invokes service based on home slice 2, the visited network will also serve this request using visitor slice 1 (as home slice 2 is also mapped to visitor slice 1) . However, the MBR may be configured to 10 Mbps for home slice 2. As can be seen, home slice 1 receives more MBR than it is assigned in the home network, which may result in a waste on network resource, whereas home slice 2 receives less MBR than it is assigned in the home network, which may lead to service degradation or service disruption. Therefore, there exists deficiencies under this shared MBR assignment scheme.

In this disclosure, a dedicated MBR assignment scheme is disclosed, as shown in Table 2 below.

Table 2: Dedicated MBR Assignment

In this dedicated MBR assignment scheme, the MBR is assigned in a home slice level. Using Table 2 as an example, home slice 1 is mapped to visitor slice 1. This mapping forms a network slice pair including the home slice and the mapped visitor slice (i.e., home slice 1, visitor slice 1) . A dedicated MBR for this pair may be set to 10 Mbps, which is the same as the MBR set for home slice 1 when the UE is in the home network. Similarly, home slice 2 is mapped to visitor slice 1. This mapping forms a network slice pair (home slice 2, visitor slice 1) . A dedicated MBR for this pair may be set to 20 Mbps, which is also the same as the MBR set for home slice 1 when the UE is in the home network. As can be seen, when the UE roams to a visited network, the MBR assignment goes to each particular home slice. Therefore, the visited network may gain finer control on a roaming UE in the perspective of network slicing.

In one implementation, a triplet representing the MBR configuration (or MBR assignment) may be formed by: the home slice, the corresponding visitor slice, and the assigned MBR.

In one implementation, a PDU session ID may be added to the triplet, for identifying the PDU session associated with the home slice/visitor slice.

The MBR configuration may be used by, for example, a RAN node or other relevant node, for creating/establishing/activating/updating a PDU session associated with the pair of the home slice and its corresponding visitor slice.

The MBR assignment may happen in various scenarios. For example:

● when the UE visits the visited network and initiates a registration request;

● When the UE initiates a service request;

● When there is an update on the MBR assignment;

● When the serving AMF of the UE changes from a source AMF to a target AMF;

● When the UE is switched over from a source RAN to a target RAN (e.g., handover scenario) .

Meanwhile, various network elements, such as AMF, RAN, and SMF may be involved in the MBR assignment. In a handover scenario, the source RAN and the target RAN may also get involved.

In this disclosure, various embodiments are described below to cover the MBR assignment in various use cases.

Embodiment 1: MBR Configuration –from AMF to RAN

In this embodiment, the MBR configuration may be passed from an AMF to a RAN in various user cases. An example use case may include a UE in a visited network initiating a request to establish a PDU session. With reference to FIG. 5, the exemplary steps are described in details below.

In this disclosure, when a message or signaling is transmitted to/from a RAN, unless explicitly specified, it is to be understood that the message or the signaling is sent to a RAN node (e.g., a gNodeB, an ng-eNB, an eNB, a nodeB, etc. ) in the RAN.

Step 1

The UE initiates a Registration Request towards the RAN. The RAN selects an AMF for the UE and forwards the Registration Request to the AMF.

Step 2a &2b

If the AMF does not have subscription data for the UE, the AMF may retrieve the subscription data from the UDM by invoking Nudm_SDM_Get in step 2a. In step 2b, the UMD may return UE subscription data to the AMF. The subscription data may contain a list of network slices subscribed by the UE in the home network. For example, the list may be a list of S-NSSAIs. The subscription data may further include MBR information for each of the S-NSSAIs.

Step 3a &3b

In step 3a, the AMF may subscribe to updates of UE subscriber data by invoking Nudm_SDM_Subscribe with UDM, so it gets notified when the subscription data is modified. For example, when an MBR for a subscribed network slice is updated, the AMF will get notified.

In step 3b, the UDM may send a response message to the AMF indicating the execution status of step 3a.

Step 4

The AMF selects a PCF for Access and Mobility control policy and sends Npcf_AMPolicyControl_Create request to the PCF. The request includes the subscribed network slice information. Specifically, the subscribed network slice information may include a list of: (subscribed home slice, its mapped visitor slice (also referred to as visited network slice) , MBR information associated with the pair of home slice and mapped visitor slice) . As an example, a list may be in the format of:

[(home network slice 1, visited

network slice

1, 10 Mbps) , (home network slice 2, visited network slice 1, 20 Mbps) , (home network slice 3, visited

network slice

2, 10 Mbps) …]

Again, like described earlier, identification of a slice may include the S-NSSAI of the slice.

Step 5

Based on its policy, the PCF decides and returns the corresponding network slice information for authorized (or allowed) network slices by sending an Npcf_AMPolicyControl_Create Response message to the AMF.

In certain scenarios, it is possible that not all subscribed home slices of a UE are supported or authorized in the visited network. The PCF returns authorized network slice information to the AMF. The authorized network slice information may be in the same or similar format as the list described in step 4. For example, a list of authorized (or allowed) network slices may be in the format of:

[ (home network slice 1, visited

network slice

1, 10 Mbps) , (home network slice 2, visited network slice 1, 20 Mbps) ] . In this example, home network slice 3 is not authorized in the visited network, so it’s not in the list.

Step 6

The AMF accepts the UE registration and sends a Registration Accept message towards the UE.

Step 7

The UE initiates a PDU Session Establishment Request towards the AMF via the RAN. From the list of authorized network slices, the UE may include in the request one or more pair of: a home network slice and a corresponding visited network slice.

The network slice may be identified by the S-NSSAI of the slice. The home network slice may be identified by the S-NSSAI of the slice in the HPLMN, and the visited network slice may be identified by the S-NSSAI of the slice in the VPLMN.

Step 8

The AMF interacts with the SMF to establish the PDU session (s) as requested by the UE. For each PDU session to be established, the SMF performs the PDU Session Establishment procedure and then sends the AMF the created PDU session ID, the associated home network slice and its corresponding visited network slice (e.g., PDU session ID, S-NSSAI of the HPLMN, and S-NSSAI of the VPLMN) .

Step 9

The AMF sends an N2 PDU Session Request message to the RAN. The N2 PDU Session Request message may carry the PDU session id, the associated home network slice and its corresponding visited network slice. Additionally, the AMF may provide MBR information associated with the pair of home network slice and the corresponding visited network slice. The RAN may store the MBR information in the UE context.

In this step, the MBR information is dedicated for the pair of home network slice and visited network slice.

Step 10

The RAN may interact with the UE via Access Network (AN) specific signaling. Information from the SMF (in step 8 above) may be sent to the UE. The AN specific signaling may be for resource setup and may include a PDU Session Establishment Accept message. For example, a Radio Resource Control (RRC) Connection Reconfiguration message may be sent to the UE to establish the necessary RAN resources following QoS requirement for the PDU session. In this disclosure, an MBR configuration may refer to MBR information, and its associated home network slice and its corresponding visited network slice. The MBR configuration may further include the PDU session ID of the corresponding PDU session. For PDU session establishment, the MBR configuration may be referenced by the RAN.

The RAN may also allocate RAN tunnel resource for the PDU session, and pass the RAN tunnel information to the UE.

Step 11

The RAN sends N2 PDU Session Response to the AMF. In a successful case, the response may indicate that the PDU session is successfully established and may include the PDU session ID, session management (SM) related information, AN tunnel information, etc.

Embodiment 2: MBR Configuration –from AMF to RAN

In this embodiment, the MBR configuration may be passed from an AMF to a RAN. An example use case may include a UE in a visited network initiating a service request. With reference to FIG. 6, the exemplary steps are described in details below.

Step 1

The UE initiates a service request towards the AMF via the RAN. The service request may include a list of PDU sessions to be activated.

Step 2

For PDU sessions indicated by the service request in step 1, the AMF may request the SMF to activate the PDU sessions by sending a Nsmf_PDUSession_UpdateSMContext request message to the SMF.

Step 3

The SMF may activate the PDU sessions and send a Nsmf_PDUSession_UpdateSMContext response message to the RAN.

Step 4

The AMF may send an INITIAL CONTEXT SETUP REQUEST to the RAN including information for all the active PDU sessions. The information may include the PDU session id, the associated home network slice and its corresponding visited network slice, as well as MBR information associated with the pair of home network slice and visited network slice. The RAN may store the MBR related configuration in the UE context. For example, the MBR related configuration may include a list of entries, with each entry corresponds to a PDU session. Each entry in the list may include: a PDU session ID, an associated home network slice and its corresponding visited network slice, and MBR information associated with the pair of home network slice and visited network slice.

Step 5

The RAN may send an INITIAL CONTEXT SETUP RESPONSE to the AMF. The RAN may report the execution result for each PDU session resource that is requested to be setup.

Step 6

The RAN performs RRC Connection Reconfiguration with the UE. The PDU session requested by the UE in step 1 may be activated, with consideration of the corresponding MBR configuration.

Embodiment 3: MBR Configuration Update –from AMF to RAN

For an established PDU session associated with a network slice, the network slice configuration may get updated. The updated information may need to be distributed to the RAN and/or other concerning network elements, so that the RAN may make the corresponding update, for example, to the UE context. With reference to FIG. 7, the exemplary steps are described in details below.

Step 0

In this step, the RAN has existing UE context with regard to MBR configuration.

Step 1

The UDM notifies the AMF that the MBR information for a subscribed network slice (or a list of subscribed network slices) is changed by using Nudm_SDM_Notify.

Step 2

The AMF sends the updated MBR configuration (for each subscribed network slice with update) to the PCF by using Npcf_AMPolicyControl_Update request. The updated MBR configuration may include MBR information, associated pair of home network slice and its corresponding visited network slice.

Step 3

The PCF provides to the AMF the corresponding authorized MBR for each pair of home network slice and its corresponding visited network slice.

Step 4

The AMF may send a UE CONTEXT MODIFICATION REQUEST message to the RAN to update the MBR configuration for each pair of home network slice and its corresponding visited network slice that experiences the MBR update, so the RAN may update the corresponding UE context.

Step 5

The RAN may send a UE CONTEXT MODIFICATION RESPONSE message to the AMF.

Embodiment 4: MBR Configuration –from Target AMF to Target RAN

In the visited network, the UE may need to be switched from a source RAN (S-RAN) to a target RAN (T-RAN) . For example, this may happen in a handover procedure. For another example, there may be a faulty condition in the serving RAN, and the UE needs to be switched to another RAN. The MBR configuration needs to be passed to the T-RAN in order to create/establish the PDU session properly. With reference to FIG. 8, the exemplary steps are described in details below. Although the example uses handover procedure as an example, this principle applies in general when the UE switches from one RAN to another.

Step 1

When the UE moves and the S-RAN decides to trigger a relocation via N2, the S-RAN may send a Handover Required message to the source AMF (S-AMF) . The Handover Required message may include a list of PDU sessions that need to be switched over. As an example, all existing PDU sessions with active User Plane (UP) connections may be included in the Handover Required message.

Step 2

When the S-AMF can't serve the UE anymore, the S-AMF may select a target AMF (T-AMF) and send a Namf_Communication_CreateUEContext Request to the T-AMF to transfer the UE context information, the UE context information may include MBR configuration (e.g., MBR information, associated pair of home network slice and its corresponding visited network slice) .

Step 3

For each PDU Session indicated by S-RAN, the T-AMF may invoke the Nsmf_PDUSession_UpdateSMContext Request to the associated SMF.

Step 4

The SMF may first check if an N2 Handover for the indicated PDU session can be accepted. If the N2 handover for the PDU session is accepted, the SMF may send an Nsmf_PDUSession_UpdateSMContext response to the T-AMF. The response may include N2 Session Management (SM) information which may contain: N3 UP address and the Uplink (UL) Core Network (CN) tunnel ID of the User Plane Function (UPF) , the Quality of Service (QoS) parameters, etc.

Step 5

The T-AMF may determine the T-RAN for the handover and send Handover Request message to the T-RAN. The Handover Request may include an N2 SM Information list (e.g. PDU Session id, associated pair of home network slice and its corresponding visited network slice) . The Handover Request may also include the MBR information associated with the pair of home network slice and its corresponding visited network slice.

As described earlier, the home network slice may be represented by the HPLMN S-NSSAI, and the visited network slice may be represented the VPLMN S-NSSAI.

Step 6

The T-RAN sends a Handover Request Acknowledge to the T-AMF. The Handover Request Acknowledge may include N2 SM information related to each PDU session in the list of PDU sessions that need to be switched over. For each PDU session in the list, the N2 SM information may include T-RAN N3 addressing information (e.g., N3 UP address and tunnel ID of T-RAN for the PDU session) .

Step 7

For each PDU session in the list of PDU sessions that need to be switched over, there is a corresponding SMF which may be indicated by the PDU session ID. For each PDU session in the list, the T-AMF may send the its N2 SM information to the corresponding SMF.

Step 8

The SMF may send an Nsmf_PDUSession_UpdateSMContext Response message per PDU session to T-AMF.

Step 9

The T-AMF may supervise/monitor the Nsmf_PDUSession_UpdateSMContext Response message from the involved SMFs. At expiry of the maximum wait time or when all Nsmf_PDUSession_UpdateSMContext Response messages are received, the T-AMF may send an Namf_Communication_CreateUEContext Response to the S-AMF.

Step 10

Handover Execution procedure is performed, the UE is switched over to the T-RAN. PDU sessions may be established based on respective MBR configuration (e.g., MBR information, associated pair of home network slice and its corresponding visited network slice, and/or PDU session ID) .

Embodiment 5: MBR Configuration –from Source RAN to Target RAN

In this embodiment, the MBR information may be passed directly from the S-RAN to the T-RAN. For example, if the handover is an Xn based inter RAN handover. With reference to FIG. 9, the exemplary steps are described in details below. Although the example uses handover procedure as an example, this principle applies in general when the UE switches from one RAN to another.

Step 1

The S-RAN node may initiate the handover procedure by sending a HANDOVER REQUEST message to the T-RAN node. The request may include the MBR configuration (e.g., MBR information, associated pair of home network slice and its corresponding visited network slice) . The MBR configuration may further include a corresponding PDU session ID.

Step 2

The T-RAN node may store the received MBR configuration in the UE context, and use the received MBR configuration for the UE, for example, when establishing or creating PDU sessions.

Embodiment 6: MBR Configuration –from Old AMF to New AMF then to RAN

When a UE initiates a registration request or registration update with a current AMF, the AMF may be a different one compared with the previous serving AMF that the UE made the previous registration. In this case, the current AMF (or new AMF, target AMF) may request UE context from the previous AMF (or old AMF, source AMF) . The UE context may include MBR configuration. Once the current AMF acquires the UE context, it may also distribute the MBR configuration to the RAN serving the UE. Therefore, on the RAN side, for each PDU session in the UE context, the RAN may be informed on the corresponding MBR configuration. An MBR configuration may refer to MBR information, and its associated home network slice and its corresponding visited network slice. The MBR configuration may further include the PDU session ID of the corresponding PDU session.

With reference to FIG. 10, the exemplary steps are described in details below.

Step 1

The UE initiates Registration Request towards the RAN. If the serving AMF has changed since last Registration procedure, the RAN selects a new AMF for the UE and forward the Registration Request to the new AMF.

Step 2

If the 5G Global Unique Temporary Identifier (5G-GUTI) of the UE was included in the Registration Request, the new AMF may send an Namf_Communication_UEContextTransfer request message to the old AMF to request the UE Context.

Step 3

The old AMF may send to the new AMF an Namf_Communication_UEContextTransfer response message. The response message may include MBR configuration for each slice pair (home network slice and its corresponding visited network slice) . For example, the response message may include a list of MBR configurations, with each entry in the list corresponding to a slice pair.

Step 4a &4b

If the new AMF does not have subscription data for the UE, the new AMF may retrieve the subscription data from the UDM by invoking Nudm_SDM_Get in step 4a. In step 4b, the UMD may return UE subscription data to the new AMF. The subscription data may contain a list of network slices subscribed by the UE in the home network. For example, the list may be a list of S-NSSAIs. The subscription data may further include MBR information for each of the S-NSSAIs.

Step 5a &5b

In step 5a, the new AMF may subscribe to updates of UE subscriber data by invoking Nudm_SDM_Subscribe with UDM, so it gets notified when the subscription data is modified. For example, when an MBR for a subscribed network slice is updated, the new AMF will get notified.

In step 5b, the UDM may send a response message to the new AMF indicating the execution status of step 5a.

Step 6

The new AMF selects a PCF for Access and Mobility control policy and sends Npcf_AMPolicyControl_Create request to the PCF. The request includes the subscribed network slice information. Specifically, the subscribed network slice information may include a list of: (subscribed home slice, its mapped visitor slice (also referred to as visited network slice) , MBR information associated with the pair of home slice and mapped visitor slice) . As an example, a list may be in the format of:

[ (home network slice 1, visited

network slice

2, 10 Mbps) …]

Step 7

[ (home network slice 1, visited

network slice

Step 8

The AMF accepts the UE registration and sends Registration Accept message towards the UE.

Step 9

The AMF sends an N2 message to the RAN to forward the list of MBR configuration for each slice pair. The RAN may store the list in the UE context.

Step 10

The UE initiates a PDU Session Establishment Request towards the new AMF via the RAN. From the list of authorized network slices, the UE may include in the request a pair of: a home network slice and a corresponding visited network slice. The request may also include multiple pairs of home network slices and corresponding visited network slices.

Step 11

The new AMF interacts with other network elements (such as PCF and/or SMF, which is not shown in the figure) to establish the PDU session (s) as requested by the UE. For each PDU session to be established, the SMF performs the PDU Session Establishment procedure and then sends the new AMF the created PDU session ID, the associated home network slice and its corresponding visited network slice (e.g., PDU session ID, S-NSSAI of the HPLMN, and S-NSSAI of the VPLMN) .

Step 12

The new AMF sends an N2 PDU Session Request message to the RAN. The N2 PDU Session Request message may carry the PDU session id, the associated home network slice and its corresponding visited network slice. It is to be noted that the MBR information associated with the home network slice and its corresponding visited network slice, has been forwarded to the RAN in step 9 above. Therefore, the RAN is able to lookup the MBR configuration corresponding to the PDU session which is identified by the PDU session id.

Optionally, in the N2 PDU Session Request message, the new AMF may choose to provide MBR information associated with the pair of home network slice and the corresponding visited network slice.

Step 13

Step 14

The RAN sends N2 PDU Session Response to the new AMF. In a successful case, the response may indicate that the PDU session is successfully established and may include the PDU session ID, session management (SM) related information, AN tunnel information, etc.

In this disclosure, a list of information such as a list of MBR configurations (one configuration for each slice pair) may be sent together in one single message (aggregation manner) . A list of information may also be sent in multiple messages, with each message carrying one or more elements in the list.

In this disclosure, various embodiments are disclosed for providing MBR configuration of network slices when the UE is in a visited network. The MBR configuration is at home slice level and applies to the pair of home slice and its corresponding visited network slice. The MBR configuration may be passed from an AMF to a RAN, or from a first RAN to a second RAN. On the RAN side, for each PDU session in the UE context, the RAN may be informed on the corresponding initial MBR configuration as well as any update thereof.

In this disclosure, the steps in each embodiment are for illustration purposes only and other alternatives may be derived based on the disclosed embodiments as desired. For example, only part of the steps may need to be performed. For another example, the sequence of the steps may be adjusted. For another example, several steps may be combined (e.g., several messages may be combined in one message) . For yet another example, a single step may be split (e.g., one message may be sent via two sub-messages) .

In this disclosure, the message name is for exemplary purpose. Message with other name may be used to achieve same functionality. For example, to carry the MBR configuration.

The accompanying drawings and description above provide specific example embodiments and implementations. The described subject matter may, however, be embodied in a variety of different forms and, therefore, covered or claimed subject matter is intended to be construed as not being limited to any example embodiments set forth herein. A reasonably broad scope for claimed or covered subject matter is intended. Among other things, for example, subject matter may be embodied as methods, devices, components, systems, or non-transitory computer-readable media for storing computer codes. Accordingly, embodiments may, for example, take the form of hardware, software, firmware, storage media or any combination thereof. For example, the method embodiments described above may be implemented by components, devices, or systems including memory and processors by executing computer codes stored in the memory.

Throughout the specification and claims, terms may have nuanced meanings suggested or implied in context beyond an explicitly stated meaning. Likewise, the phrase “in one embodiment/implementation” as used herein does not necessarily refer to the same embodiment and the phrase “in another embodiment/implementation” as used herein does not necessarily refer to a different embodiment. It is intended, for example, that claimed subject matter includes combinations of example embodiments in whole or in part.

In general, terminology may be understood at least in part from usage in context. For example, terms, such as “and” , “or” , or “and/or, ” as used herein may include a variety of meanings that may depend at least in part on the context in which such terms are used. Typically, “or” if used to associate a list, such as A, B or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B or C, here used in the exclusive sense. In addition, the term “one or more” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a, ” “an, ” or “the, ” may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present solution should be or are included in any single implementation thereof. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present solution. Thus, discussions of the features and advantages, and similar language, throughout the specification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, advantages and characteristics of the present solution may be combined in any suitable manner in one or more embodiments. One of ordinary skill in the relevant art will recognize, in light of the description herein, that the present solution can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present solution.

Claims

A method for wireless communication, performed by a first Network Element (NE) in a wireless network, the method comprising:

transmitting a first message to a second NE in the wireless network, the first message comprising a first network slice configuration of a first home network slice subscribed by a User Equipment (UE) in a home network of the UE, wherein the first network slice configuration comprises:

a mapping between the first home network slice and a first visited network slice, the first visited network slice being assigned to the UE to serve the first home network slice when the UE is in a visited network of the UE; and

a first Maximum Bit Rate (MBR) information which applies to the first home network slice, and does not apply to other home network slices of the UE.
The method of claim 1, wherein the first network slice configuration further comprises an identification of a Protocol Data Unit (PDU) session corresponding to the first home network slice.
The method of claim 1, wherein the first message further comprises a second network slice configuration of a second home network slice subscribed by the UE in the home network of the UE, so that the second NE is configured to configure a second network slice service corresponding to the second home network slice based on the second network slice configuration, wherein the second network slice configuration comprises:

a mapping between the second home network slice and the first visited network slice, the first visited network slice being further assigned to the UE to serve the second home network slice when the UE is in the visited network; and

a second MBR information which applies to the second home network slice, and does not apply to other home network slices of the UE.
The method of claim 1, wherein the UE is receiving service in the visited network, the first NE comprises an Access and Mobility Management Function (AMF) of the visited network, and the second NE comprises a Radio Access Network (RAN) node of the visited network.
The method of claim 4, wherein the RAN node comprises one of: a gNodeB; or a ng-eNB.
The method of claim 4, wherein before transmitting the first message to the second NE, the method further comprising:

in response to receiving a second message from the UE for requesting an establishment of a PDU session corresponding to the first home network slice, interacting with a Session Management Function (SMF) for establishing the PDU session; and

receiving from the SMF, a third message comprising:

a network slice pair comprising the first home network slice and the first visited network slice; and

an identification of the PDU session.
The method of claim 6, wherein:

the first message comprises an N2 PDU Session Request message; and

the second message comprises a PDU session establishment request message.
The method of claim 4, wherein before transmitting the first message to the second NE, the method further comprising:

receiving from the UE, a service request message requesting to activate or create a PDU session corresponding to the first home network slice.
The method of claim 8, wherein:

the first message comprises an Initial Context Setup Request message.
The method of claim 4, further comprising:

receiving a second message from a Policy Control Function (PCF) , the second message comprising an updated first MBR information; and

transmitting a third message to the second NE, the third message comprising an updated first network slice configuration, wherein the updated first network slice configuration comprises:

the mapping between the first home network slice and the first visited network slice; and

the updated first MBR information which applies to the first home network slice.
The method of claim 10, wherein:

the second message comprises an access and mobility policy control service update response message; and

the third message comprises a UE Context Modification Request message.
The method of claim 1, wherein:

the UE is in a procedure in which the UE is switched from a source RAN node to a target RAN node;

the first NE comprises a target AMF which determines the target RAN node; and

the second NE comprise the target RAN node.
The method of claim 12, wherein:

the procedure comprises a handover procedure; and

the first message comprises a handover request message.
The method of claim 12, wherein before transmitting the first message to the second NE, the method further comprises:

receiving, from a source AMF associated with the source RAN, a second message comprising:

the mapping between the first home network slice and the first visited network slice; and

the first MBR information.
The method of claim 14, wherein the second message comprises a Namf_Communication_CreateUEContext Request message.
The method of claim 1, wherein:

the first NE comprises a source RAN node;

the second NE comprises a target RAN node; and

the UE is in a procedure in which the UE is switched from the source RAN node to the target RAN node.
The method of claim 16, wherein:

the procedure comprises a handover procedure; and

the first message comprises a handover request message.
The method of claim 16, wherein after the UE is switched to the target RAN, the target RAN serves a PDU session corresponding to the first home network slice based on the first MBR information.
The method of claim 1, wherein the UE is receiving service in the visited network, the first NE comprises a source AMF, and the second NE comprises a target AMF.
The method of claim 19, wherein before transmitting the first message to the second NE, the method further comprising:

receiving from the target AMF, a second message requesting to transfer a context of the UE from the source AMF to the target AMF.
The method of claim 20, wherein:

the second message is trigger by the target AMF receiving a registration request from the UE; and

the UE is changing its registration from the source AMF to the target AMF.
The method of claim 21, wherein:

the first message comprises a Namf_Communication_UEContextTransfer response message; and

the second message comprises a Namf_Communication_UEContextTransfer request message.
The method of claim 19, wherein:

a reception of the first message on the target AMF triggers the target AMF to transmit a third message to a RAN node serving the UE; and

the third message comprises the first network slice configuration.
A method for wireless communication, performed by a first NE in a wireless network, the method comprising:

receiving a first message from a second NE in the wireless network, the first message comprising a first network slice configuration of a first home network slice subscribed by a UE in a home network of the UE, wherein the first network slice configuration comprises:

a mapping between the first home network slice and a first visited network slice, the first visited network slice being assigned to the UE to serve the first home network slice when the UE is in a visited network of the UE; and

a first MBR information which applies to the first home network slice, and does not apply to other home network slices of the UE.
The method of claim 24, wherein the first network slice configuration further comprises an identification of a Protocol Data Unit (PDU) session corresponding to the first home network slice.
The method of claim 24, wherein the first message further comprises a second network slice configuration of a second home network slice subscribed by the UE in the home network of the UE, wherein the second network slice configuration comprises:

a mapping between the second home network slice and the first visited network slice, the first visited network slice being further assigned to the UE to serve the second home network slice when the UE is in the visited network; and

a second MBR information which applies to the second home network slice, and does not apply to other home network slices of the UE.
The method of claim 24, wherein the UE is receiving service in the visited network, the first NE comprises a RAN node of the visited network, and the second NE comprises an AMF of the visited network.
The method of claim 27, wherein the RAN node comprises one of: a gNodeB; or a ng-eNB.
The method of claim 27, wherein:

the first message comprises an N2 PDU Session Request message; and

the method further comprises establishing a PDU session corresponding to the first home network slice based on the first MBR information.
The method of claim 27, wherein:

the first message comprises an Initial Context Setup Request message; and

the method further comprises activating a PDU session corresponding to the first home network slice based on the first MBR information.
The method of claim 24, wherein:

the UE is in a procedure in which the UE is switched from a source RAN to a target RAN;

the first NE comprises a target RAN node;

the second NE comprises a target AMF which determines the target RAN node; and

the first message comprises a handover request message.
The method of claim 31, wherein:

the procedure comprises a handover procedure; and

the first message comprises a handover request message.
The method of claim 31, further comprising establishing a PDU session corresponding to the first home network slice based on the first MBR information, wherein the PDU session is served by the first NE.
The method of claim 24, wherein:

the first NE comprises a target RAN node;

the second NE comprises a source RAN node;

the UE is in a procedure in which the UE is switched from the source RAN to the target RAN; and

the first message comprises a handover request message.
The method of claim 34, wherein:

the procedure comprises a handover procedure; and

the first message comprises a handover request message.
The method of claim 24, further comprising:

transmitting a second message to a third NE, the second message comprising the first network slice configuration.
The method of claim 24, further comprising:

receiving from the UE, a second message requesting to establish a PDU session, the second message comprises a slice pair which is formed by the first home network slice and the first visited network slice and corresponds to the PDU session; and

transmitting a third message to a third NE, the third message comprising a PDU session ID corresponding to the PDU session, and the slice pair, wherein the third message triggers the third NE to establish the PDU session based on the first network slice configuration.
The method of claim 37, wherein:

the second message comprises a PDU session establishment request message; and

the third message comprises an N2 PDU session request message.
The method of claim 37, wherein:

the first NE comprises a target AMF;

the second NE comprises a source AMF; and

the third NE comprises a RAN node serving the UE.
A device comprising a memory for storing computer instructions and a processor in communication with the memory, wherein the processor, when executing the computer instructions, is configured to implement a method in any one of claims 1-39.
A computer program product comprising a non-transitory computer-readable program medium with computer code stored thereupon, the computer code, when executed by one or more processors, causing the one or more processors to implement a method of any one of claims 1-39.