Wireless communication schemes for supporting network slices

Abstract

A method of wireless communication includes transmitting, by a wireless device, a first message requesting a protocol data unit (PDU) session establishment to an access and mobility management function, the first message including application-related information identifying a target application of the wireless device, and receiving, by the wireless device, i) a second message accepting the PDU session establishment from the access and mobility management function, the second message including supported application information, or ii) a third message rejecting the PDU session establishment from the access and mobility management function, the third message including an identification (ID) of an existing PDU session to allow the wireless device to reuse the existing PDU session for the target application.

Description

TECHNICAL FIELD

[0001] This document relates to systems, devices, and techniques for wireless communication. BACKGROUND

[0002] Efforts are ongoing to define next generation wireless communication networks that provide greater deployment flexibility, support for a variety of devices and services, and different techniques for efficient bandwidth utilization. SUMMARY

[0003] Various methods and apparatuses are provided for supporting network slicing in a wireless communication system.

[0004] One example aspect discloses a method of wireless communication. The method includes transmitting, by a wireless device, a first message to an access and mobility management function requesting establishment of a protocol data unit (PDU) session, the first message including application related information identifying a target application of the wireless device; and receiving, by the wireless device, from the access and mobility management function, i) a second message accepting establishment of the PDU session, the second message including supported application information, or ii) a third message rejecting establishment of the PDU session and including an identification (ID) of an existing PDU session to allow the wireless device to repurpose the existing PDU session for the target application.

[0005] In another example aspect, another method of wireless communication is disclosed. The method includes accepting, by an access and mobility management function, a first message from a wireless device requesting establishment of a protocol data unit (PDU) session to establish the PDU session, the first message including application related information identifying a target application of the wireless device; and transmitting, by the access and mobility management function to the wireless device, i) a second message accepting establishment of the PDU session, the second message including supported application information for the PDU session, or ii) a third message rejecting establishment of the PDU session, the third message including an identification (ID) of an existing PDU session to allow the wireless device to repurpose the existing PDU session for the target application.

[0006] In another example aspect, another method of wireless communication is disclosed.

[0007] In another example aspect, another method of wireless communication is disclosed.

[0008] In another example aspect, an apparatus of wireless communication is disclosed, the apparatus comprising a processor configured to implement a method described herein.

[0009] In another example aspect, the various techniques described herein can be implemented as processor-executable code and stored on a computer-readable program medium.

[0010] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description, the drawings, and the claims. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 An example architecture to which various embodiments can be applied is shown.

[0012] Figure 2 An existing procedure for registering a UE to a set of network slices is shown.

[0013] Figure 3 An example procedure for registering a UE to a set of network slices based on some implementations of the disclosed technology is shown.

[0014] Figure 4 An example of a PDU session establishment procedure in a non-roaming and local break-out roaming scenario based on some implementations of the disclosed technology is shown.

[0015] Figure 5 An example of a PDU session establishment procedure in a home routed roaming scenario based on some implementations of the disclosed technology is shown.

[0016] Figure 6 A block diagram of an example of a wireless communication device is shown.

[0017] Figure 7 An example wireless communication network is shown.

[0018] Figure 8 And Figure 9 An example flow diagram of a wireless communication method based on some implementations of the disclosed technology is shown. DETAILED DESCRIPTION

[0019] In this document, the section headings are included for ease of understanding and do not limit the scope of the disclosed implementations and techniques to the section in which the heading appears. Moreover, some embodiments are described with reference to the Third Generation Partnership Project (3GPP) New Radio (NR) standards (“5G”), and the described techniques can be implemented in different wireless systems that implement protocols other than 5G protocols.

[0020] Network slicing has been supported in 5G systems, including network slice selection, network slice mapping in roaming scenarios, network slice specific authentication and authorization (NSSAA), and network slice admission control (NSAC), etc.

[0021] The term network slice refers to a logical network that provides specific network capabilities and network characteristics. The term network slice instance refers to a collection of network function instances and required resources (e.g., computing resources, storage resources, and networking resources) that form a deployed network slice.

[0022] In 5G systems, it is required that a UE should be able to support network slice related capabilities. For example, a UE needs to support configured network slice selection assistance information (NSSAI), allowed NSSAI, rejected NSSAI, requested NSSAI, and pending NSSAI. Configured NSSAI, allowed NSSAI, rejected NSSAI, requested NSSAI, and pending NSSAI are defined in the related specifications, and each of configured NSSAI, allowed NSSAI, rejected NSSAI, requested NSSAI, and pending NSSAI includes one or more single network slice selection assistance information (S-NSSAI). Another example is that a UE should support a UE route selection policy (URSP) and select the most appropriate network slice for application traffic based on the URSP. Since current 5G UEs do not support network slice related capabilities, UEs need complex updates and long-term evolution to support network slice related capabilities, and thus UEs become a bottleneck for deploying network slice features.

[0023] In view of the above problems, various embodiments of the disclosed technology provide a method of supporting network slicing on the network side to reduce the impact of UEs.

[0024] Figure 1 An example architecture to which various embodiments can be applied is shown. As Figure 1 The example architecture shown corresponds to a 5G system (5GS) architecture, which includes the following network functions (NFs):

[0025] 1) UE, User Equipment.

[0026] 2) RAN, Radio Access Network.

[0027] 3) AMF, Access and Mobility Management Function. This NF includes functions such as: UE mobility management, reachability management, connection management and registration management. The AMF terminates the RAN control plane (CP) interface N2 and the Non-Access Stratum (NAS) interface N1, NAS ciphering and integrity protection. The AMF also distributes the SM (Session Management) NAS to a suitable SMF (Session Management Function) via the N11 interface. During the registration procedure, the AMF can determine the allowed NSSAI and the rejected NSSAI with a cause value based on the requested NSSAI received from the UE. The AMF also determines the registration area in which the UE can use all S-NSSAIs of the allowed NSSAI. The AMF sends the allowed NSSAI, the rejected NSSAI with a cause value and the registration area to the UE.

[0028] 4) UDM, Unified Data Management. This NF manages the subscription profile of the UE. The subscription data is stored in the Unified Data Repository (UDR). The subscription information includes network slice related subscription data for mobility management and session management. The AMF and SMF retrieve subscription data from the UDM.

[0029] 5) NSSF, Network Slice Selection Function. This NF supports the following functions: selection of a set of network slice instances that serve the UE; determination of the allowed NSSAI, and if needed, mapping to the home public land mobile network (HPLMN) S-NSSAI; determination of the configured NSSAI, and if needed, mapping to the HPLMN S-NSSAI; determination of a set of AMFs to be used to serve the UE, or based on configuration, possibly by querying the Network Repository Function (NRF), a list of one or more candidate AMFs.

[0030] 6) SMF, Session Management Function. This NF includes the following functionalities: session establishment, modification and release; UE IP address allocation and management; selection and control of User Plane (UP) function; etc.

[0031] 7) UPF, User Plane Function. This NF serves as an anchor point for intra- / inter- radio access technology (RAT) mobility and as an external PDU session point of interconnect to Data Network (DN). The UPF also routes and forwards packets according to the routing information from SMF. The UPF also buffers downlink (DL) data while the UE is in idle mode.

[0032] 8) PCF, Policy Control Function. This NF supports unified policy framework to govern the network behavior. The PCF provides access management policies to AMF, or session management policies to SMF, or UE policies to UEs. The PCF can access UDR to obtain subscription information relevant for policy decisions.

[0033] Figure 2 Existing procedures are shown to register a UE to a set of network slices.

[0034] Operation 1: When a UE registers to a PLMN (public land mobile network) through an Access Type, the UE can provide the requested NSSAI to the network in the NAS layer, which contains one or more S-NSSAI corresponding to one or more slices that the UE wants to register to.

[0035] The requested NSSAI shall be one of the following:

[0036] - the default configured NSSAI, i.e. if the UE has neither configured NSSAI nor allowed NSSAI for the serving PLMN;

[0037] - the configured NSSAI or a subset thereof, e.g. if the UE has no allowed NSSAI for the access type for the serving PLMN;

[0038] - the allowed NSSAI or a subset thereof for the access type through which the requested NSSAI is sent; or

[0039] - Allowed NSSAI or a subset thereof for an access type (over which the requested NSSAI is sent) and one or more S-NSSAIs from the configured NSSAI that are not yet in the allowed NSSAI for that access type.

[0040] Operation 2: When the AMF selected by the RAN receives the UE registration request during the registration procedure, the AMF can query the UDM to retrieve the UE subscription information including the subscribed S-NSSAIs.

[0041] Operation 3: The AMF verifies whether one or more S-NSSAIs in the requested NSSAI are granted based on the subscribed S-NSSAIs. To identify the subscribed S-NSSAIs, the AMF can use the mapped HPLMN S-NSSAIs provided by the UE in the NAS message for each S-NSSAI of the requested NSSAI.

[0042] Operation 4: When the UE context in the AMF does not already include the allowed NSSAI for the corresponding access type, the AMF queries the NSSF for network slice selection, unless the AMF is allowed to determine whether the AMF can serve the UE based on configuration in the AMF. The IP address or FQDN (Fully qualified domain name) of the NSSF is configured locally in the AMF.

[0043] Operation 5: The NSSF returns the allowed NSSAI to the AMF. One or more rejected S-NSSAIs with a rejection reason indicating the reason why the one or more S-NSSAIs have been rejected can also be returned.

[0044] Operation 6: The serving AMF shall determine the registration area such that all S-NSSAIs in the allowed NSSAI are available in all tracking areas of the registration area.

[0045] Operation 7: The AMF sends a registration accept message to the UE including the allowed NSSAI, the mapped HPLMN NSSAI of the allowed NSSAI if provided, the rejected S-NSSAIs and related cause values, and the registration area. For a rejected NSSAI for the current PLMN, the UE shall not attempt to use this S-NSSAI in the current PLMN. For a rejected NSSAI for the current registration area, the UE shall not attempt to use this S-NSSAI in the current registration area.

[0046] After completing the registration procedure, the UE can request to establish a PDU session. The requested S-NSSAI of the PDU session is derived based on the URSP rules at the UE side or UE local configuration, and the requested S-NSSAI should be within the allowed NSSAI. The UE shall send a PDU session establishment request including the S-NSSAI to the network.

[0047] SUMMARY

[0048] To use the network slicing feature, the UE needs to support the network slicing related capability. However, the current 5G UE does not support the network slicing related capability, and the UE needs complex update and long term evolution to support the network slicing related capability. Therefore, various embodiments of the disclosed technology provide enhancements of the network slicing at the network side to avoid the UE supporting the network slicing feature.

[0049] Some embodiments of the disclosed technology suggest UE registration schemes that allow the UE to register to the network without providing the requested NSSAI from the UE to the network. The network side generates the allowed NSSAI based on the subscribed NSSAI, the supported NSSAI in the current tracking area (TA). The network does not provide the allowed NSSAI and / or the rejected NSSAI to the UE. The AMF can also receive the URSP rules from the PCF and store the URSP rules in the UE context.

[0050] In various embodiments of the disclosed technology, during the PDU session establishment procedure, the UE provides the application related information to the network side (e.g., AMF), so the network side can generate the requested S-NSSAI for the application based on the URSP rules and the allowed NSSAI. Then, the AMF continues the PDU session establishment procedure as usual.

[0051] If the PDU session establishment request is accepted, the AMF can include the supported application information of the PDU session (based on, e.g., the URSP rules) in the PDU session establishment accept message sent to the UE. If the above new application information is received, the UE shall match the new application information with the supported application information of the existing PDU session. If there is an existing PDU session that can support the new application requirement, the UE shall reuse the existing PDU session for the new application. If there is no existing PDU session that can support the new application requirement, the UE shall initiate the PDU session establishment procedure with the new application information sent to the network.

[0052] If there is an existing PDU session that can serve the application information based on the request, e.g., URSP rules, the AMF can reject the PDU session establishment request and indicate the PDU session ID that can support the requested application in the PDU session establishment reject message sent to the UE. The UE shall reuse the indicated PDU session for the requested application.

[0053] Embodiment Example 1: UE registers to a set of network slices

[0054] Figure 3 An example procedure for registering a UE to a set of network slices based on some embodiments of the disclosed technology is shown.

[0055] Operation 1: When a UE registers to a PLMN through an access type, the UE does not provide the requested NSSAI to the network, which contains one or more S-NSSAI corresponding to one or more slices that the UE wants to register to.

[0056] Operation 2: When the network function responsible for access and mobility management (e.g., AMF, AMF is used as an example in the following procedure) selected by the RAN receives the UE registration request during the registration procedure, the AMF queries the network function (e.g., UDM, UDM is used as an example in the following procedure) managing the subscription profile of the UE to retrieve the UE subscription information including the subscribed NSSAI.

[0057] After operation 2, proceed with option A including operation 3 and operation 4, or proceed with option B including operation 5. After either option A or option B is performed, operation 6 will be performed.

[0058] Option A: There is another network function (e.g., NSSF, NSSF is used as an example in the following procedure) managing network slice selection.

[0059] Operation 3: The AMF queries the NSSF for network slice selection with, e.g., the subscribed NSSAI, the UE current location, the potential registration area as input. The potential registration area includes a list of one or more tracking area identities (TAIs) that the AMF intends to include in the registration area. The IP address or FQDN of the NSSF is locally configured in the AMF.

[0060] Operation 4: The NSSF considers, for example, the UE's subscribed NSSAI, the UE's current location, the supported NSSAI of the current TA, the potential registration area, the supported NSSAI of the potential registration area, to return the allowed NSSAI to the AMF. The NSSF can also return the rejected NSSAI with a rejection cause indicating the reason why the S-NSSAI has been rejected. Because the UE does not provide the requested NSSAI in the registration request message, the allowed NSSAI and the rejected NSSAI are generated without considering the requested NSSAI. In roaming scenarios, the allowed NSSAI and the rejected NSSAI include the serving PLMN S-NSSAI and the corresponding mapped HPLMN S-NSSAI.

[0061] Option B: The AMF manages the network slice selection.

[0062] Operation 5: If the AMF is allowed to determine the network slice selection based on configuration, the AMF generates the allowed NSSAI and the rejected NSSAI based on, for example, the UE's subscribed NSSAI, the UE's current location, the supported NSSAI of the current TA, the potential registration area, and the supported NSSAI of the potential registration area. Because the UE does not provide the requested NSSAI in the registration request message, the allowed NSSAI and the rejected NSSAI are generated without considering the requested NSSAI. In roaming scenarios, the allowed NSSAI and the rejected NSSAI include the serving PLMN S-NSSAI and the corresponding mapped HPLMN S-NSSAI.

[0063] Operation 6: The serving AMF shall determine the registration area such that all S-NSSAIs in the allowed NSSAI are available in all tracking areas of the registration area. The AMF stores the allowed NSSAI, the rejected NSSAI, and the registration area of the UE.

[0064] Operation 7: The AMF sends the registration accept message to the UE, which includes the registration area but does not include the allowed NSSAI and the rejected NSSAI.

[0065] Operation 8: The AMF queries the network function responsible for policy control (e.g., the PCF, which is used as an example in the following procedure) to retrieve the UE policy information including the UE Route Selection Policy (URSP) rules. The AMF stores the URSP rules in the UE context.

[0066] Embodiment Example 2: PDU Session Establishment Procedure in Non-Roaming and Local Breakout Roaming Scenarios

[0067] Figure 4Examples of PDU session establishment procedures in non-roaming and local breakout roaming scenarios are shown. In the non-roaming scenario, the PDU session establishment procedure is shown in Figure 1A. In the local breakout roaming scenario, the PDU session establishment procedure is shown in Figure 1B. Figure 3 As discussed, after the UE registers to the network, the UE can request PDU session establishment.

[0068] Operation 1 from the UE to the AMF: NAS message (PDU session ID, Request Type, Data Network Names (DNNs) requested by the UE, Application related information, N1 SM container (PDU session establishment request)).

[0069] The PDU session establishment request is included in the NAS message and encapsulated in the N1 SM container, which will be transparently forwarded to the network function responsible for session management (e.g., SMF, SMF is used as an example in the following procedure). The NAS message sent by the UE is encapsulated in the N2 message to the AMF by the RAN.

[0070] The NAS message sent by the UE does not include S-NSSAI related to the PDU session. The NAS message includes application related information that identifies the target application of the UE. The target application can refer to an application that needs to obtain connection through PDU session establishment. In some embodiments, the application related information includes, for example, application descriptor, IP (Internet Protocol) descriptor, DNN (Data Network Name), connection capability. The connection capability can indicate “ims (IP Multimedia Subsystem)”, “mms (Multimedia Messaging Service)”, “internet”, etc. The application related information does not include S-NSSAI information. The PDU session establishment request in the N1 SM container can also include the application related information. If the application related information is also included in the PDU session establishment request, the AMF will not forward the received application related information to the SMF. If the application related information is not included in the PDU session establishment request, the AMF can forward the received application related information to the SMF.

[0071] After operation 1, operation 2a or operation 2b is performed.

[0072] Operation 2a: AMF to UE: PDU session establishment reject (target PDU session ID).

[0073] The AMF can determine whether there exists an existing PDU session capable of serving the application-related information corresponding to the target application. If there exists an existing PDU session capable of serving the application-related information corresponding to the target application based on, for example, URSP rules, the AMF can reject the PDU session establishment request by sending a PDU session establishment reject message to the UE. In this case, the AMF can indicate the PDU session ID capable of supporting the target application in the PDU session establishment reject message sent to the UE. The UE shall reuse the indicated PDU session for the target application.

[0074] Operation 2b: If there does not exist an existing PDU session capable of serving the application-related information corresponding to the target application, the AMF selects a suitable S-NSSAI from the allowed NSSAI based on, for example, the received application-related information, URSP rules, and UE subscription information. Then, the AMF selects a suitable SMF to serve the PDU session based on, for example, the selected S-NSSAI, application-related information, URSP rules. The AMF stores the relationship of the selected S-NSSAI, PDU session ID, SMF ID, etc.

[0075] Operation 3: AMF to SMF: Nsmf_PDUSession_CreateSMContext request (selected S-NSSAI, application-related information, PDU session ID, AMF ID, request type, N1 SM container (PDU session establishment request), user location information). The Nsmf_PDUSession_CreateSMContext request corresponds to a request for creating a "SM (Session Management) context" service operation in the SMF for a given PDU session.

[0076] The AMF sends the selected S-NSSAI to the SMF. The AMF can forward the received application-related information to the SMF.

[0077] Operation 4: SMF to AMF: Nsmf_PDUSession_CreateSMContext response (SM context ID). The SM context ID identifies the SM context created in the SMF for the UE.

[0078] Operation 5: The SMF selects a user plane function (e.g., UPF, which is used as an example in the following procedure) to serve the PDU session based on, for example, the UE location, the selected S-NSSAI, and the application-related information.

[0079] Operation 6: The SMF initiates a N4 session establishment procedure with the selected UPF.

[0080] Operation 7: SMF to AMF: PDU session establishment accept.

[0081] If the network accepts the connection with the requested DN, the SMF shall create a PDU Session Establishment Accept message.

[0082] Operation 8: AMF to UE: PDU Session Establishment Accept (Supported Application Information).

[0083] If the PDU Session Establishment Request is accepted, the N2 SM information carries information that the AMF shall forward to the RAN, which includes the selected S-NSSAI. The N1 SM container contains the PDU Session Establishment Accept that the AMF shall provide to the UE, which does not include S-NSSAI information.

[0084] The AMF can include the supported application information for the PDU session in the PDU Session Establishment Accept message sent to the UE (based on e.g. URSP rules). The supported application information for the PDU session does not include S-NSSAI information. The AMF shall store the supported application information for the PDU session.

[0085] After receiving the PDU Session Establishment Accept message with the supported application information, there is new application traffic that needs to be transported and possibly triggers PDU session establishment. The new application traffic can be referred to as requested application information. The UE shall determine whether there is an existing PDU session whose supported application information matches the requested application information. If there is an existing PDU session whose supported application information matches the requested application information, the UE shall re-use the existing PDU session for the target application. If there is no existing PDU session whose supported application information matches the requested application information, the UE shall initiate the PDU session establishment procedure with the application related information sent to the network.

[0086] Embodiment Example 3: PDU Session Establishment procedure in home routed roaming scenario

[0087] Figure 5 The PDU Session Establishment procedure in a home routed roaming scenario is shown. After the UE registers to the network as discussed in Figure 3 the UE can request PDU session establishment.

[0088] Operation 1: UE to AMF: NAS message (PDU Session ID, Request Type, UE requested DNN, Application related information, N1 SM container (PDU Session Establishment Request)).

[0089] The PDU Session Establishment Request is included in the NAS message and encapsulated in the N1 SM container, which will be transparently forwarded to the SMF. The NAS message sent by the UE is encapsulated by the RAN in the N2 message to the AMF.

[0090] The NAS message sent by the UE does not include S-NSSAI related to the PDU session. The NAS message includes application related information identifying a target application of the UE. The target application can refer to an application that needs to obtain a connection through PDU session establishment. In some embodiments, the application related information includes, for example, an application descriptor, an IP descriptor, a DNN, a connection capability. The connection capability can indicate "ims", "mms", "internet", etc. The application related information does not include S-NSSAI information. The PDU session establishment request in the N1 SM container can also include the application related information. If the application related information is also included in the PDU session establishment request, the AMF does not forward the received application related information to the SMF. If the application related information is not included in the PDU session establishment request, the AMF can forward the received application related information to the SMF.

[0091] After operation 1, operation 2a or operation 2b is performed.

[0092] Operation 2a: AMF to UE: PDU session establishment reject (target PDU session ID).

[0093] The AMF can determine whether there is an existing PDU session capable of serving the application related information corresponding to the target application. If there is an existing PDU session capable of serving the application related information corresponding to the target application based on, for example, URSP rules, the AMF can reject the PDU session establishment request by sending a PDU session establishment reject message to the UE. In this case, the AMF can indicate a PDU session ID capable of supporting the target application in the PDU session establishment reject message sent to the UE. The UE should reuse the indicated PDU session for the target application.

[0094] Operation 2b: If there is no existing PDU session capable of serving the application related information corresponding to the target application, the AMF selects a mapped HPLMN S-NSSAI from the mapped NSSAI of the corresponding service PLMN S-NSSAI and allowed NSSAI based on, for example, the received application related information, URSP rules, and UE subscription information.

[0095] Then, the AMF selects a V-SMF (visited SMF) serving the PDU session based on, for example, the selected service PLMN S-NSSAI, the application related information, URSP rules.

[0096] The AMF also selects an H-SMF (home SMF) serving the PDU session based on, for example, the selected HPLMN S-NSSAI, the application related information, URSP rules.

[0097] The AMF stores the association of the selected one or more S-NSSAI, PDU Session ID, V-SMF ID, H-SMF ID, etc.

[0098] Operation 3: AMF to V-SMF: Nsmf_PDUSession_CreateSMContext Request (VPLMN S-NSSAI, mapped HPLMN S-NSSAI, H-SMF ID, Application related information, PDU Session ID, AMF ID, Request Type, N1 SM Container (PDU Session Establishment Request), User Location Information).

[0099] The AMF sends the selected service PLMN S-NSSAI and the corresponding mapped HPLMN S-NSSAI to the V-SMF. The AMF provides the identity of the selected H-SMF. The AMF can forward the received Application related information to the V-SMF.

[0100] Operation 4: V-SMF selects a V-UPF serving the PDU Session based on e.g. UE location, selected VPLMN S-NSSAI and Application related information.

[0101] Operation 5: V-SMF initiates the N4 Session Establishment procedure over the selected V-UPF.

[0102] Operation 6: V-SMF to H-SMF: Nsmf_PDUSession_Create Request (SUPI (Subscription Permanent Identifier), PDU Session ID, HPLMN S-NSSAI, Application related information, V-SMF ID, AMF ID).

[0103] The V-SMF sends the selected HPLMN S-NSSAI to the H-SMF. The V-SMF can forward the received Application related information to the H-SMF.

[0104] Operation 7: H-SMF selects a H-UPF (home UPF) serving the PDU Session based on e.g. UE location, selected HPLMN S-NSSAI and Application related information.

[0105] Operation 8: H-SMF initiates the N4 Session Establishment procedure over the selected H-UPF.

[0106] Operation 9: H-SMF to V-SMF: PDU Session Establishment Accept.

[0107] Operation 10: V-SMF to AMF: PDU Session Establishment Accept.

[0108] Operation 11: AMF to UE: PDU Session Establishment Accept (Supported Application Information).

[0109] If the PDU Session Establishment Request is accepted, the N2 SM information carries information that the AMF should forward to the RAN, which includes the selected VPLMN S-NSSAI and the corresponding mapped HPLMN S-NSSAI. The N1 SM container contains the PDU Session Establishment Accept that the AMF should provide to the UE, which does not include S-NSSAI information.

[0110] The AMF can include the supported application information for the PDU session in the PDU Session Establishment Accept message sent to the UE (based on e.g. URSP rules). The supported application information for the PDU session does not include S-NSSAI information. After receiving the PDU Session Establishment Accept message with the supported application information, there is new application traffic that needs to be transported and possibly triggers PDU session establishment. The new application traffic can be referred to as requested application information. The UE should determine whether there is an existing PDU session that matches the supported application information and the requested application information. If there is an existing PDU session that matches the supported application information and the requested application information, the UE should re-use the existing PDU session for the target application. If there is no existing PDU session that matches the supported application information and the requested application information, the UE should initiate a PDU session establishment procedure with the application related information sent to the network.

[0111] In this patent document, various solutions are provided to support one or more network slices. Some aspects from the UE, AMF, and PCF can include one or more features as outlined below:

[0112] The UE is configured to perform at least one of the following operations:

[0113] - send, to the AMF, a PDU Session Establishment Request with application related information.

[0114] In some embodiments, the application related information includes an application descriptor and / or an IP descriptor and / or a DNN and / or a connection capability and / or other information describing the traffic that needs PDU session transport. The connection capability can indicate “ims”, “mms”, “internet”, etc. The application related information does not include S-NSSAI information.

[0115] - receiving a PDU session establishment accept from the AMF including supported application information for the PDU session. After receiving the PDU session establishment accept with supported application information, there is new application traffic that needs to be transported. The new application traffic can be referred to as requested application information. The UE can determine whether there is an existing PDU session whose supported application information matches the requested application information.

[0116] - receiving a PDU session establishment reject from the AMF including a target PDU session ID. After receiving the PDU session establishment reject with the target PDU session ID, the UE can reuse the indicated PDU session for the requested application.

[0117] The AMF is configured to perform at least one of the following operations:

[0118] - receiving UE policy information including UE Route Selection Policy (URSP) rules from the PCF and storing the UE policy information in the UE context.

[0119] - receiving a PDU session establishment request from the UE with application related information.

[0120] In some embodiments, the application related information includes application descriptor and / or IP descriptor and / or DNN and / or connection capability and / or other information describing the traffic that needs to be transported by the PDU session. The connection capability can indicate "ims", "mms", "internet", etc. The application related information does not include S-NSSAI information.

[0121] - selecting, based on the received application related information and the URSP rules, a serving PLMN S-NSSAI in roaming case and a corresponding mapped HPLMN S-NSSAI from the allowed NSSAI for the PDU session.

[0122] - sending a PDU session establishment accept to the UE including supported application information for the PDU session and storing the supported application information for the PDU session.

[0123] - sending a PDU session establishment reject to the UE including a target PDU session ID.

[0124] The PCF is configured to perform the following operations:

[0125] - sending UE policy information including UE Route Selection Policy (URSP) rules to the AMF.

[0126] Figure 6is a block diagram of an example implementation of a wireless communication device 1200. The methods described herein can be implemented by the device 1200. In some embodiments, the device 1200 can be a base station or network equipment of a wireless network. In some embodiments, the device 1200 can be a user equipment (e.g., a wireless device or user equipment, UE). The device 1200 includes one or more processors (e.g., processor electronics 1210, transceiver electronics 1215, and one or more antennas 1220 for transmitting and receiving wireless signals). The device 1200 can include memory 1205, which can be used for storing data and instructions used by the processor electronics 1210. The device 1200 can also include additional network interfaces to additional equipment of one or more core networks or network operators. The additional network interfaces (not explicitly shown in the figure) can be wired (e.g., fiber or Ethernet) or wireless.

[0127] Figure 7 An example of a wireless communication system 1300 in which various techniques described herein can be implemented is depicted. The system 1300 includes a base station 1302, which can have communication connections with a core network (1312) and communication connections to a transmission medium 1304 to communicate with one or more user equipment 1306. The user equipment 1306 can be a smart phone, a tablet, a machine-to-machine communication device, and an Internet of Things (IoT) device, etc.

[0128] Some preferred embodiments can include the following solutions.

[0129] 1. A method of wireless communication (e.g., the method 800 as shown in Figure 8 FIG. 8), comprising: transmitting, by a wireless device, a first message requesting a protocol data unit (PDU) session establishment to an access and mobility management function, the first message including application-related information identifying a target application of the wireless device (810); and receiving, by the wireless device, from the access and mobility management function, i) a second message accepting the PDU session establishment, the second message including supported application information, or ii) a third message rejecting the PDU session establishment, the third message including an identification (ID) of an existing PDU session to allow the wireless device to reuse the existing PDU session for the target application (820).

[0130] 2. The method of solution 1, wherein the application-related information includes at least one of: one or more application descriptors, one or more Internet Protocol (IP) descriptors, one or more Data Network Names (DNNs), one or more connection capabilities, or other information describing application traffic that needs PDU session transport.

[0131] 3. The method of solution 1, wherein the first message, the second message, and the third message do not include single-network slice selection assistance information (S-NSSAI) that identifies a network slice.

[0132] 4. The method of solution 1, further comprising, after receiving the second message, determining whether there is an existing PDU session that supports application information of a request related to an application that triggered the PDU session establishment; and in a case that there is the existing PDU session, applying the existing PDU session for the target application, or in a case that there is not the existing PDU session, initiating a PDU session establishment procedure with the requested application information.

[0133] 5. The method of solution 1, further comprising: sending, by the wireless device to the access and mobility management function, a registration request for the wireless device to register to a mobile network by an access type, the registration request omitting a requested network slice selection assistance information (NSSAI) that contains one or more S-NSSAIs corresponding to one or more slices that the wireless device requests to register to; and receiving, by the wireless device from the access and mobility management function, a registration accept that omits an allowed NSSAI and a rejected NSSAI.

[0134] 6. A method of wireless communication (e.g., method 900 as Figure 9 illustrated), comprising: receiving, by an access and mobility management function from a wireless device, a first message that requests a protocol data unit (PDU) session establishment to establish a PDU session, the first message including application-related information that identifies a target application of the wireless device (910); and sending, by the access and mobility management function to the wireless device, i) a second message that accepts the PDU session establishment or ii) a third message that rejects the PDU session establishment, the second message including supported application information for the PDU session, the third message including an identification (ID) of an existing PDU session to allow the wireless device to reuse the existing PDU session for the target application (920).

[0135] 7. The method of solution 6, wherein the application-related information includes at least one of: one or more application descriptors, one or more internet protocol (IP) descriptors, one or more data network names (DNNs), one or more connection capabilities, or other information that describes application traffic that needs PDU session transport.

[0136] 8. The method of solution 6, wherein the first message, the second message, and the third message do not include single network slice selection assistance information (S-NSSAI) that identifies a network slice.

[0137] 9. The method of solution 6, further comprising selecting, by the access and mobility management function, a single network slice selection assistance information (S-NSSAI) from a plurality of S-NSSAI in an allowed NSSAI based on at least one of: the application related information, a UE route selection policy (URSP) rule, or subscription information of the wireless device.

[0138] 10. The method of solution 9, further comprising selecting, by the access and mobility management function, a session management function based on at least one of: the selected S-NSSAI, the application related information, or a UE route selection policy (URSP) rule.

[0139] 11. The method of solution 10, further comprising sending, by the access and mobility management function to the session management function, a request for creating an SM context, the request including the application related information that allows the session management function to select a user plane function to serve the PDU session based on at least one of: a location of the wireless device, the selected S-NSSAI, or the application related information.

[0140] 12. The method of solution 6, further comprising adding, by the access and mobility management function, the supported application information for the PDU session to the second message prior to sending the second message.

[0141] 13. The method of solution 6, further comprising storing, by the access and mobility management function, the supported application information for the PDU session.

[0142] 14. The method of solution 6, further comprising determining, by the access and mobility management function, whether there is an existing PDU session that supports application information related to an application traffic that triggered the PDU session establishment request; and wherein the third message is sent in response to determining that there is the existing PDU session that supports the application information of the request.

[0143] 15. The method of solution 6, further comprising sending, by the access and mobility management function, a query to a network slice selection function regarding network slice selection based on at least one of: a subscribed NSSAI, a location of the wireless device, or a potential registration area comprising a list of tracking area identities (TAIs); and receiving, by the access and mobility management function, an allowed NSSAI and a rejected NSSAI from the network slice selection function, the allowed NSSAI and the rejected NSSAI being generated without considering a requested NSSAI.

[0144] 16. The method of solution 6, further comprising generating, by the access and mobility management function, an allowed NSSAI and a rejected NSSAI based on at least one of: a subscribed NSSAI, a location of the wireless device, a supported NSSAI of a current tracking area (TA), a potential registration area, or a supported NSSAI of the potential registration area, wherein the allowed NSSAI and the rejected NSSAI are generated without considering a requested NSSAI.

[0145] 17. The method of solution 6, further comprising sending, by the access and mobility management function, a query to a policy control function for retrieving policy information for the wireless device, the policy information comprising UE route selection policy (URSP) rules; and storing, by the access and mobility management function, the URSP rules for the wireless device in a context of the wireless device.

[0146] 18. The method of solution 6, further comprising selecting, by the access and mobility management function, a home public land mobile network (HPLMN) S-NSSAI and a corresponding visited public land mobile network (VPLMN) S-NSSAI based on at least one of: the application related information, a UE route selection policy (URSP) rule, or subscription information of the wireless device.

[0147] 19. A wireless communication apparatus comprising a processor configured to implement a method recited in any of solutions 1 to 18.

[0148] 20. A computer storage medium having code stored thereon, the code, when executed by a processor, causing the processor to implement a method recited in any of solutions 1 to 18.

[0149] The disclosed and other embodiments, modules and the functional operations described in this document can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this document and their structural equivalents, or in combinations of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer readable medium for execution by, or to control the operation of, data processing apparatus. The computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more of them. The term "data processing apparatus" encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers. The apparatus can include, in addition to hardware, code that creates an execution environment for the mentioned computer program in order to execute it, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus.

[0150] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and are interconnected by a communication network.

[0151] The processes and logic flows described in this document can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0152] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0153] While this document contains many specifics, these should not be construed as limitations on the scope of the invention or of what can be claimed, but rather as descriptions of features specific to particular embodiments. Some features described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring or implying that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results.

[0154] Only a few examples and implementations are disclosed. Variations, modifications, and enhancements of the described examples and implementations and other implementations can be made based on what is disclosed.

Claims

1. A method of wireless communication, comprising: sending, by a wireless device, a first message to an access and mobility management function requesting a protocol data unit (PDU) session establishment, the first message including application related information identifying a target application of the wireless device; and receiving, by the wireless device, a second message from the access and mobility management function accepting the PDU session establishment or a third message from the access and mobility management function rejecting the PDU session establishment, the second message including supported application information, the third message including an identification (ID) of an existing PDU session to allow the wireless device to reuse the existing PDU session for the target application, the first message, the second message, and the third message not including single network slice selection assistance information (S-NSSAI) identifying a network slice.

2. The method of claim 1, wherein, the application related information including at least one of one or more application descriptors, one or more internet protocol (IP) descriptors, one or more data network names (DNNs), one or more connection capabilities, or other information describing application traffic requiring PDU session transport.

3. The method of claim 1, further comprising: determining, after receiving the second message, whether there is an existing PDU session that supports requested application information related to application traffic that triggered the PDU session establishment; and using the existing PDU session for the target application if the existing PDU session exists or initiating a PDU session establishment procedure with the requested application information if the existing PDU session does not exist.

4. The method of claim 1, further comprising: sending, by the wireless device, a registration request to the access and mobility management function to register the wireless device to a mobile network by an access type, the registration request omitting a requested network slice selection assistance information (NSSAI) containing one or more S-NSSAIs corresponding to one or more slices to which the wireless device requests to register; and receiving, by the wireless device, a registration accept from the access and mobility management function, the registration accept omitting an allowed NSSAI and a rejected NSSAI.

5. A method of wireless communication, comprising: receiving, by an access and mobility management function, a first message from a wireless device requesting a protocol data unit (PDU) session establishment to establish a PDU session, the first message including application related information identifying a target application of the wireless device; and sending, by the access and mobility management function to the wireless device, a second message accepting the PDU session establishment or a third message rejecting the PDU session establishment, the second message including supported application information for the PDU session, the third message including an identification (ID) of an existing PDU session to allow the wireless device to reuse the existing PDU session for the target application, the first message, the second message, and the third message not including single network slice selection assistance information (S-NSSAI) identifying a network slice.

6. The method of claim 5, wherein, The application-related information includes at least one of one or more application descriptors, one or more Internet Protocol (IP) descriptors, one or more Data Network Names (DNNs), one or more connection capabilities, or other information describing application traffic that needs PDU session transport.

7. The method of claim 5, further comprising: selecting, by the access and mobility management function, a single-network slice selection assistance information (S-NSSAI) from a plurality of S-NSSAIs in an allowed network slice selection assistance information (NSSAI) based on at least one of the application-related information, a UE route selection policy (URSP) rule, or subscription information of the wireless device.

8. The method of claim 7, further comprising: selecting, by the access and mobility management function, a session management function based on at least one of the selected S-NSSAI, the application-related information, or a UE route selection policy (URSP) rule.

9. The method of claim 8, further comprising: sending, by the access and mobility management function to the session management function, a request for creating a session management (SM) context, the request including the application-related information that allows the session management function to select a user plane function to serve the PDU session based on at least one of a location of the wireless device, the selected S-NSSAI, or the application-related information.

10. The method of claim 5, further comprising: prior to sending the second message: adding, by the access and mobility management function, the supported application information for the PDU session to the second message.

11. The method of claim 5, further comprising: storing, by the access and mobility management function, the supported application information for the PDU session.

12. The method of claim 5, further comprising: determining, by the access and mobility management function, whether there is an existing PDU session that supports application information related to an application traffic that triggered the PDU session establishment request; and wherein the third message is sent in response to determining that there is the existing PDU session that supports the requested application information.

13. The method of claim 5, further comprising: sending, by the access and mobility management function to a network slice selection function, a query for network slice selection based on at least one of a subscribed NSSAI, a location of the wireless device, or a list of potential registration areas including tracking area identities (TAIs); and receiving, by the access and mobility management function from the network slice selection function, an allowed NSSAI and a rejected NSSAI, the allowed NSSAI and the rejected NSSAI being generated without considering a requested NSSAI.

14. The method of claim 5, further comprising: generating, by the access and mobility management function, allowed NSSAI and rejected NSSAI based on at least one of: a subscribed NSSAI, a location of the wireless device, a supported NSSAI of a current tracking area (TA), a potential registration area, or a supported NSSAI of the potential registration area, wherein the allowed NSSAI and the rejected NSSAI are generated without considering a requested NSSAI.

15. The method of claim 5, further comprising: sending, by the access and mobility management function, a query to a policy control function for retrieving policy information for the wireless device, the policy information comprising UE route selection policy (URSP) rules; and storing, by the access and mobility management function, the URSP rules for the wireless device in a context of the wireless device.

16. The method of claim 5, further comprising: selecting, by the access and mobility management function, a home public land mobile network (HPLMN) S-NSSAI and a corresponding visited public land mobile network (VPLMN) S-NSSAI based on at least one of: the application related information, a UE route selection policy (URSP) rule, or subscription information of the wireless device.

17. An apparatus for wireless communication, comprising a processor configured to implement a method recited by any of claims 1 to 16.

18. A computer storage medium having code stored thereon, the code, when executed by a processor, causing the processor to implement a method recited by any of claims 1 to 16.

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