A session establishment method, a handover method and a device

Abstract

A method and apparatus for session establishment and handover in a wireless communication system are provided. The method includes: receiving, by a first node, a message from a second node, the message including a single network slice selection assistance resource (S-NSSAI) of a PDU session; and allocating, by the first node, resources for the PDU session based on the message received from the second node, wherein when the first node supports the S-NSSAI of the PDU session, it allocates resources corresponding to the S-NSSAI of the PDU session for the PDU session; and when the first node does not support the S-NSSAI or the resources corresponding to the S-NSSAI are unavailable or overloaded, the first node allocates other available resources for the PDU session.

Description

Technical Field

[0001] The present disclosure relates to wireless communication technologies. More specifically, the present disclosure relates to a session establishment method, a handover method, and a device in a wireless communication system. Background Art

[0002] In order to meet the increasing demand for wireless data communication services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems".

[0003] Wireless communication is one of the most successful innovations in modern history. Recently, the number of subscribers to wireless communication services has exceeded 5 billion and continues to grow rapidly. Due to the increasing popularity of smart phones and other mobile data devices (e.g., tablet computers, laptop computers, netbooks, e-book readers, and machine type devices) among consumers and enterprises, the demand for wireless data services is growing rapidly. To meet the high growth of mobile data services and support new applications and deployments, it is crucial to improve the efficiency and coverage of wireless interfaces.

[0004] The present invention provides improved session establishment methods, handover methods, and devices for problems such as service interruption caused by session handover failure when a UE moves or hands over between different base stations or session establishment failure during the session establishment process.

[0005] The above information is presented as background information only to help understand the present disclosure. No determination or assertion is made as to whether any of the above information is applicable as prior art to the present disclosure. Summary of the Invention

[0006] The present invention provides improved session establishment methods, handover methods, and devices.

[0007] According to one aspect of the present invention, there is provided a method and apparatus for session establishment and handover in a wireless communication system. The method includes: receiving, by a first node, a message from a second node, the message including a single network slice selection assistance information (S-NSSAI) of a PDU (Protocol Data Unit) session; and allocating, by the first node, resources for the PDU session based on the message received from the second node, wherein when the first node supports the S-NSSAI of the PDU session, it allocates resources corresponding to the S-NSSAI of the PDU session for the PDU session; and when the first node does not support the S-NSSAI or the resources corresponding to the S-NSSAI are unavailable or overloaded, the first node allocates other available resources for the PDU session.

[0008] According to another aspect of the present invention, a base station in a wireless communication system includes: a transceiver configured to receive or transmit signals; and at least one processor configured to receive a message from a second node, the message including a single network slice selection assistance information (S-NSSAI) of a PDU session; and allocate resources for the PDU session based on the message received from the second node, wherein when the base station supports the S-NSSAI of the PDU session, it allocates resources corresponding to the S-NSSAI of the PDU session for the PDU session; and when the base station does not support the S-NSSAI or the resources corresponding to the S-NSSAI are unavailable or overloaded, the base station allocates other available resources for the PDU session.

[0009] According to another aspect of the present invention, a core network node in a wireless communication system includes: a transceiver configured to receive or transmit signals; and at least one processor configured to receive a message from a second node, the message including a single network slice selection assistance information (S-NSSAI) of an initially allocated PDU session; and allocate resources for the PDU session at least partially based on the message received from the second node, wherein when the core network node supports the S-NSSAI of the PDU session, it allocates network slice resources corresponding to the S-NSSAI of the PDU session for the PDU session; and when the core network node does not support the S-NSSAI or the network slice resources corresponding to the S-NSSAI are unavailable or overloaded, the core network node allocates other available network slice resources for the PDU session.

[0010] Beneficial effects

[0011] The present invention provides an improved session establishment method, handover method and device. It can avoid or reduce the problem of service interruption caused by session handover failure when a user equipment (UE) moves or hands over between different base stations, or the problem of session establishment failure during the session establishment process. At the same time, during the process of UE movement or handover or session establishment, the network can always preferentially configure the ongoing session to the most suitable resources, and when the most suitable resources are unavailable, it can serve the UE to the greatest extent possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Shows a system architecture diagram of System Architecture Evolution (SAE) according to an embodiment of the present disclosure;

[0013] Figure 2 Shows an architecture diagram of a next-generation communication system or 5G communication system according to an embodiment of the present disclosure;

[0014] Figure 3 Shows an exemplary method for PDU session establishment and handover according to an embodiment of the present disclosure;

[0015] Figure 4 Shows Figure 3 An embodiment of the exemplary method shown in;

[0016] Figure 5 Shows Figure 3 Another embodiment of the exemplary method shown in;

[0017] Figure 6 Shows Figure 3 Another embodiment of the exemplary method shown in;

[0018] Figure 7 Shows Figure 3 Another embodiment of the exemplary method shown in;

[0019] Figure 8 Shows another exemplary method for PDU session establishment and handover according to an embodiment of the present disclosure;

[0020] Figure 9 Shows Figure 8 An embodiment of the exemplary method shown in;

[0021] Figure 10 Shows Figure 8 Another embodiment of the exemplary method shown in;

[0022] Figure 11 Shows another exemplary method for PDU session establishment and handover according to an embodiment of the present disclosure;

[0023] Figure 12 shows Figure 11 an embodiment of the exemplary method shown in

[0024] Figure 13 shows Figure 11 another embodiment of the exemplary method shown in

[0025] Figure 14 shows Figure 11 yet another embodiment of the exemplary method shown in

[0026] Figure 15 shows another exemplary method for PDU session establishment and handover according to an embodiment of the present disclosure. Detailed Description

[0027] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the various embodiments of the present disclosure defined by the claims and their equivalents. It includes various specific details to facilitate understanding, but these details are only considered exemplary. Thus, those of ordinary skill in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope of the present disclosure. In addition, descriptions of well-known functions and configurations may be omitted for clarity and conciseness.

[0028] The terms and words used in the following description and claims are not limited to their philological meanings, but are used solely by the inventors to enable a clear and consistent understanding of the present disclosure. Thus, it should be apparent to those skilled in the art that the following description of the various embodiments of the present disclosure is provided for illustrative purposes only and not for the purpose of limiting the present disclosure defined by the appended claims and their equivalents.

[0029] The terms "first", "second", etc. may be used to describe various components, but the components are not limited by the terms. The terms are only used to distinguish one component from other components.

[0030] The terms used in the present disclosure are only used to describe exemplary embodiments and are not intended to limit the scope of the present disclosure. Singular expressions also include plural meanings as long as they do not conflict with the context. In the present disclosure, the terms "comprising" and "including" indicate the presence of the features, quantities, steps, operations, components, elements, or combinations thereof written in the present disclosure, but do not exclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, elements, or combinations thereof.

[0031] In this case, it can be understood that each block of the process flow diagram, as well as combinations of the flow diagrams, can be implemented by computer program instructions. Since these computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, these instructions executed by the processor of the computer or other programmable data processing device create means for implementing the functions described in the (one or more) blocks of the flow diagram. Since these computer program instructions can also be stored in a computer-usable or computer-readable memory of the computer or other programmable data processing device to implement functions in a specific manner, the computer program instructions stored in the computer-usable or computer-readable memory can also generate an article of manufacture including instruction means for performing the functions described in the (one or more) blocks of the flow diagram. Since the computer program instructions can also be installed on the computer or other programmable data processing device, a series of operation steps executed on the computer or other programmable data processing device to create a process executed by the computer can also provide steps for implementing the functions described in the (one or more) blocks of the flow diagram.

[0032] In addition, some of the modules, segments, or code that each block can represent include one or more executable instructions for performing specific (one or more) logical functions. Additionally, it should be noted that in some alternative embodiments, the functions provided in the blocks may occur regardless of the order. For example, two blocks shown consecutively can actually be executed simultaneously, or sometimes in the reverse order depending on the corresponding functions.

[0033] The example embodiments described herein are not meant to be limiting. The matters defined in the description, such as detailed construction and elements, are provided only as specific details to assist those of ordinary skill in the art in fully understanding the present disclosure. The aspects of the present disclosure generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated, and designed in various different configurations, all of which are contemplated herein. Additionally, unless the context otherwise indicates, the features shown in each drawing can be used in combination with each other. Therefore, the appended Figure One drawings are generally regarded as a component of one or more general embodiments, but it should be understood that not all of the illustrated features are necessary for each embodiment.

[0034] Depending on the situation, the expression "configured to" as used in various embodiments of the present disclosure may be used interchangeably with, for example, "suitable for", "capable of", "designed to", "adapted to", "enabled to", or "able to" in terms of hardware or software. Alternatively, in some cases, the expression "device configured to" may mean that the device "is able to" together with other devices or components. For example, the phrase "a processor is adapted (or configured) to execute A, B, and C" may refer to a dedicated processor (e.g., an embedded processor) solely for executing the corresponding operations, or a general-purpose processor (e.g., a central processing unit (CPU) or an application processor (AP)) that can execute the corresponding operations by running one or more software programs stored in a memory device.

[0035] It should be noted that there are three types of S-NSSAI involved in the present invention. One is the S-NSSAI of a PDU session, where the S-NSSAI of the PDU session is the S-NSSAI corresponding to the PDU session identifier included in the N2 SM information sent by the core network to the base station during the PDU session establishment process in the current 3GPP specification 23.502, or the S-NSSAI of the PDU session is the S-NSSAI corresponding to the PDU session identifier sent by the UE to the core network during the PDU session establishment process in the current 3GPP specification 23.502; the second is the S-NSSAI that can be configured for the PDU session when the above S-NSSAI of the PDU session is not supported, overloaded, or unavailable, hereinafter referred to as the auxiliary S-NSSAI. The third is the S-NSSAI actually configured for the PDU session by the base station according to the supported slice information, resource situation, and / or slice policy information, hereinafter referred to as the configured S-NSSAI.

[0036] Modern mobile communications are increasingly tending to provide users with high-rate multimedia services, such as Figure 1 shown in the system architecture diagram of the System Architecture Evolution (SAE). Among them:

[0037] The user equipment (UE) 101 is a terminal device for receiving data. The evolved universal terrestrial radio access network (E-UTRAN) 102 is a radio access network, which includes macro base stations (eNodeB / NodeB) that provide access to the wireless network interface for the UE. The mobility management entity (MME) 103 is responsible for managing the mobility context, session context, and security information of the UE. The serving gateway (SGW) 104 mainly provides user plane functions, and the MME 103 and SGW 104 may be in the same physical entity. The packet data network gateway (PGW) 105 is responsible for functions such as charging and lawful interception, and may also be in the same physical entity as the SGW 104. The policy and charging rules function entity (PCRF) 106 provides quality of service (QoS) policies and charging guidelines. The serving GPRS support node (SGSN) 108 is a network node device in the universal mobile telecommunications system (UMTS) that provides routing for data transmission. The home subscriber server (HSS) 109 is the home subscription subsystem of the UE, and is responsible for protecting user information including the current location of the user equipment, the address of the serving node, user security information, and the packet data context of the user equipment.

[0038] As Figure 2 shown, it is the system architecture diagram of the next-generation network or the fifth-generation 5G network. Among them:

[0039] The user equipment (UE) 201 is a terminal device for receiving data. The next-generation radio access network (NG-RAN) 202 is a radio access network, which includes base stations (gNB or eNB connected to the 5G core network (5G Core network, 5GC), and the eNB connected to the 5GC is also called ng-gNB) that provide access to the wireless network interface for the UE. The access and mobility management function entity (AMF) 203 is responsible for managing the mobility context and security information of the UE. The user plane function entity (UPF) 204 mainly provides user plane functions. The session management function entity (SMF) 205 is responsible for session management. The data network (DN) 206 includes services such as those of the operator, access to the Internet, and third-party services.

[0040] The present invention provides an improved session establishment method, handover method, and device.

[0041] An exemplary method for session establishment and handover of the present invention is as Figure 3 described. The detailed description of steps irrelevant to the present invention is omitted here. The method includes the steps:

[0042] In step 301, the first node receives a message for requesting PDU session establishment from the second node. The message contains the single network slice selection assistance information (S-NSSAI) of the PDU session to be configured, and also contains network slice policy information. When the first node does not support the S-NSSAI or the resources corresponding to the S-NSSAI are unavailable or overloaded, the first node allocates resources to the PDU session considering the network slice policy information. The network slice policy information may be a secondary S-NSSAI, and the secondary S-NSSAI may be one or more. For each PDU session, the secondary S-NSSAI may be one or more. When there are multiple secondary S-NSSAIs, the multiple secondary S-NSSAIs may have different priorities. For example, the S-NSSAI ranked earlier may have a higher priority. The first node preferentially considers the resources corresponding to the S-NSSAI with a higher priority when allocating resources.

[0043] The first node may be a base station or a core network node. The second node may be a core network node or a base station. The core network node may be an SMF or an AMF. As an example, the message received by the first node from the second node may be sent by the core network node as the second node to the base station as the first node, sent by the first base station as the second node to the second base station as the first node (e.g., sent by the source base station to the destination base station), sent by the first core network node as the second node to the second core network node as the first node (e.g., sent by the source core network node to the destination core network node), or sent by the base station as the first node to the core network node as the second node. According to the specific implementation manners of the first node and the second node, the message may be, for example, an initial UE context establishment request message (when the first node is a base station and the second node is a core network node), a PDU session resource establishment request message (when the first node is a base station and the second node is a core network node), a handover request message (when the first node is the destination base station and the second node is the core network node or the first node is the destination base station and the second node is the source base station), a handover requirement message (when the first node is the source core network node and the second node is the source base station), a path switch request confirmation message (when the first node is the destination base station and the second node is the core network node), or a create UE context request message (when the first node is the destination core network node and the second node is the source core network node), etc. The above examples are only for illustration and not for limitation.

[0044] The network slice selection policy (NSSP), the subscription information of the UE, the quality of service (QoS) information of the service, the S-NSSAI supported by the AMF, and / or the S-NSSAI supported by the SMF, etc. can be considered to determine the network slice policy information. The entity that determines the network slice policy information can be a core network node.

[0045] In step 302, the first node receives a message for a session establishment request. The first node saves the received PDU session information, including the S-NSSAI of the PDU session and the network slice policy information.

[0046] The first node considers the S-NSSAI in the message when allocating resources for the requested PDU session or when slice overload requires reallocation of resources. When the first node or the cell of the first node does not support the S-NSSAI or the slice resources corresponding to the S-NSSAI are overloaded or unavailable, the first node considers the network slice policy information to allocate resources for the PDU session. For example, the first node considers allocating resources corresponding to the secondary S-NSSAI. If the message received by the first node contains multiple secondary S-NSSAIs, the first node preferentially considers the slice resources of the S-NSSAI with a higher priority.

[0047] The method may further include the step of:

[0048] The first node sends the S-NSSAI actually configured for the PDU session to the core network. Based on the S-NSSAI actually configured for the UE, the core network can reselect the session management function entity and / or the user plane function entity for the PDU session of the UE. For example, the base station sends the S-NSSAI actually configured for the PDU session to the AMF, and the AMF reselects the SMF and / or UPF for the PDU session of the UE. Or the base station sends the S-NSSAI actually configured for the PDU session to the SMF, and the SMF reselects the UPF for the PDU session of the UE. This step is applicable when the first node is a base station.

[0049] When this method is used for handover and the second base station (target base station) does not support the S-NSSAI of a certain PDU session, resources of another network slice are configured for the PDU session according to the network slice policy information. When the second base station triggers the handover of the UE to the third base station as the source base station, as described in step 301, the handover request message includes the S-NSSAI of the PDU session and the network slice policy information. If the third base station supports the S-NSSAI, the third base station configures the PDU session on the resources corresponding to the S-NSSAI of the PDU session. This method can ensure that the most suitable resources are always configured for the PDU session of the UE.

[0050] In the case where this method is only used for handover, when the source base station triggers the handover of the UE to the target base station, as described in step 301, the message is a handover request message, which includes the S-NSSAI of the PDU session and network slice policy information; if the resources actually configured by the source base station for the PDU session are the resources corresponding to the configured S-NSSAI of the PDU session selected based on the network slice policy information, the handover request message may include the configured S-NSSAI. If the target base station supports the S-NSSAI of the PDU session, it configures the PDU session on the resources corresponding to the S-NSSAI of the PDU session. If the target base station does not support the S-NSSAI of a certain PDU session or the S-NSSAI of the PDU session is overloaded or unavailable, it configures other network slice resources for the PDU session according to the network slice policy information. This method can ensure that the most suitable resources are always configured for the PDU session of the UE. Thus, the description of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. Through this method, problems such as service interruption caused by session handover failure when the UE moves or hands over between different base stations or session establishment failure during the session establishment process can be avoided or reduced. At the same time, during the process of UE movement or handover or session establishment, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are unavailable, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0051] An embodiment of a method for session establishment and handover of the present invention is as Figure 4 described. The detailed description of steps irrelevant to the present invention is omitted here. The steps include:

[0052] In step 401, the UE sends a non-access stratum (NAS) PDU session establishment request message to the AMF. The message includes a PDU session identifier, one or more S-NSSAIs, and a UE and core network interface (N1) session management (SM) container. The S-NSSAI is among the allowed NSSAIs of the current access type.

[0053] In step 402, the AMF generates network slice policy information. The AMF can determine the network slice policy information for each PDU session based on the Network Slice Selection Policy (NSSP), the UE's subscribed information, the UE's Allowed NSSAI, the base station serving the UE, and / or the Supported S-NSSAI supported by the AMF and / or the SMF, etc. The network slice policy information can be a secondary S-NSSAI, and the secondary S-NSSAI can be one or more. For each PDU session, the secondary S-NSSAI can be one or more. When there are multiple secondary S-NSSAIs, the multiple secondary S-NSSAIs can have different priorities. For example, the S-NSSAI ranked earlier can have a higher priority.

[0054] When the AMF selects an SMF, if it needs to query the Network Slice Selection Function (NSSF) and the NF Repository Function (NRF), it can carry the network slice policy information in the network slice selection acquisition process between the AMF and the NSSF and the network function discovery request process between the AMF and the NRF, so as to select a more suitable SMF. When multiple SMFs all support the S-NSSAI of the requested PDU session, the SMF that supports the most secondary S-NSSAIs in the network slice policy information can be selected.

[0055] The AMF saves the S-NSSAI associated with the PDU session and the network slice policy information.

[0056] In step 403, the AMF sends a Create Session Management Context Request message to the selected SMF, and the network slice policy information for each PDU session requested from the SMF can be carried in the message. If the SMF does not support the S-NSSAI in the network slice policy, the SMF will update the network slice policy information to ensure that the S-NSSAIs in the network slice policy are all supported by the SMF.

[0057] In step 404, the SMF sends a Create Session Management Context Feedback message to the AMF, and the updated network slice policy information for each PDU session managed by the SMF is included in the message. The AMF saves the updated network slice policy information.

[0058] In step 405, the AMF sends an Initial Context Setup Request or PDU Session Resource Setup Request message to the base station, and the S-NSSAI and network slice policy information required to establish the PDU session are carried in the message.

[0059] It should be noted that there are three types of S-NSSAIs involved in the present invention. One is the S-NSSAI of the PDU session. The S-NSSAI of the PDU session is the S-NSSAI corresponding to the PDU session identifier included in the N2 SM information sent by the core network to the base station during the PDU session establishment process in the current 3GPP specification 23.502, or the S-NSSAI of the PDU session is the S-NSSAI corresponding to the PDU session identifier sent by the UE to the core network during the PDU session establishment process in the current 3GPP specification 23.502. The second is the S-NSSAI that can be configured for the PDU session when the S-NSSAI of the PDU session is not supported or unavailable, hereinafter referred to as the auxiliary S-NSSAI. The third is the S-NSSAI actually configured by the base station for the PDU session according to the supported slice information, resource situation, and / or slice policy information, hereinafter referred to as the configured S-NSSAI.

[0060] For the PDU session to be established, the base station preferentially configures the resources corresponding to the S-NSSAI of the PDU session for the requested PDU session. If the base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI of the PDU session are overloaded or unavailable, the base station can select the S-NSSAI serving the PDU session according to the network slice policy information. The base station can select the S-NSSAI supported by the base station with a higher priority in the network slice policy information. The S-NSSAI selected by the base station from the network slice policy information is the configured S-NSSAI, which belongs to the conditional information unit and only exists when the network slice resources corresponding to the S-NSSAI of the PDU session are not supported or overloaded or unavailable. When the network slice policy information is the auxiliary S-NSSAI, the base station selects the configured S-NSSAI from the auxiliary S-NSSAI.

[0061] The base station stores all the S-NSSAIs of the PDU sessions, the configured S-NSSAIs, and the network slice policy information.

[0062] Step 406, the base station sends a Radio Resource Control (RRC) reconfiguration message to the UE. The message contains the NAS message indicating the completion of the PDU session establishment, which carries the S-NSSAI and the configured S-NSSAI of each PDU session. If the configured S-NSSAI appears, it means that the network slice resources used for the corresponding PDU session are not the slice resources corresponding to the S-NSSAI of the PDU session, but the slice resources corresponding to the auxiliary S-NSSAI.

[0063] After receiving the message, the UE stores all the S-NSSAI and configured S-NSSAI information associated with the PDU sessions.

[0064] In step 407, the base station sends an initial context establishment response or a PDU session resource establishment response message to the AMF, and the configured S-NSSAI of the PDU session may be carried in the message.

[0065] In step 408, if the configured S-NSSAI is carried in the message, the AMF will carry the configured S-NSSAI in the update session management context request sent to the SMF.

[0066] In step 409, the SMF may reselect a UPF for the PDU session according to the configured S-NSSAI and execute the UPF selection process.

[0067] So far, a description of an embodiment of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. Through this method, the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations can be avoided or reduced. At the same time, during the process of UE movement or handover, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are unavailable, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0068] Another embodiment of a method for session establishment and handover of the present invention is as Figure 5 described. The detailed description of the steps irrelevant to the present invention is omitted here. The steps include:

[0069] In step 501, the UE sends a NAS PDU session establishment request message to the AMF. The message includes a PDU session identifier, one or more S-NSSAIs, and an N1 session management (SM) container. The S-NSSAI is among the allowed NSSAIs of the current access type.

[0070] In step 502, when the AMF selects an SMF, if it needs to query the NSSF and NRF, it can carry the NSSP in the network slice selection acquisition process between the AMF and the NSSF and the network function discovery request process between the AMF and the NRF to select a more suitable SMF.

[0071] The AMF sends a create session management context request message to the SMF. The message may carry information such as NSSP, the UE's subscription information, QoS information, allowed NSSAI, and / or the S-NSSAI supported by the network nodes serving the UE. The network nodes include core network entities and base stations.

[0072] In step 503, the SMF may determine the network slice policy information for each PDU session based on the NSSP, the UE's subscribed information, QoS information, the permitted NSSAI, and / or the supported S-NSSAI of the network serving the UE, etc. The network slice policy information may be a secondary S-NSSAI, and the secondary S-NSSAI may be one or more. For each PDU session, the secondary S-NSSAI may be one or more. When there are multiple secondary S-NSSAIs, the multiple secondary S-NSSAIs may have different priorities. For example, the S-NSSAI ranked earlier may have a higher priority.

[0073] The SMF stores the S-NSSAI and network slice policy information of the PDU session.

[0074] In step 504, the SMF sends a create session management context feedback message to the AMF, and the message contains the S-NSSAI and network slice policy information of each PDU session managed by the SMF. The AMF stores the network slice policy information.

[0075] In step 505, the AMF sends an initial context setup request or a PDU session resource setup request message to the base station, and the message carries the S-NSSAI and network slice policy information of the PDU session to be established.

[0076] For the PDU session to be established, the base station preferentially configures the resources corresponding to the S-NSSAI of the PDU session for the requested PDU session. If the base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI of the PDU session are overloaded or unavailable, the base station may select the S-NSSAI serving the PDU session according to the network slice policy information. The base station may select the S-NSSAI supported by the base station with a higher priority in the network slice policy information. The S-NSSAI selected by the base station from the network slice policy information is called the configured S-NSSAI, which belongs to the conditional information unit and only exists when the network slice resources corresponding to the S-NSSAI of the PDU session are not supported or overloaded or unavailable. When the network slice policy information is the secondary S-NSSAI, the base station selects the configured S-NSSAI from the secondary S-NSSAIs.

[0077] The base station stores the S-NSSAI, configured S-NSSAI, and network slice policy information of all PDU sessions.

[0078] In step 506, the base station sends an RRC reconfiguration message to the UE. The message contains the NAS message indicating the completion of PDU session establishment, which carries the S-NSSAI of each PDU session and the configured S-NSSAI. If the configured S-NSSAI appears, it means that the network slice resources used by the corresponding PDU session are not the slice resources corresponding to the S-NSSAI of the PDU session, but the slice resources corresponding to the secondary S-NSSAI.

[0079] After receiving the message, the UE saves the S-NSSAI and configured S-NSSAI information of all PDU sessions.

[0080] In step 507, the base station sends an initial context setup response or PDU session resource setup response message to the AMF, and the configured S-NSSAI of the PDU session may be carried in the message. In step 508, if the configured S-NSSAI is carried in the message, the AMF will carry the configured S-NSSAI in the update session management context request sent to the SMF; in step 509, the SMF may reselect a UPF for the PDU session according to the configured S-NSSAI and execute the UPF selection process. If the SMF does not receive the configured S-NSSAI information in the message, the SMF knows that the corresponding PDU session uses the slice resources corresponding to the S-NSSAI of the PDU session.

[0081] Thus, another embodiment of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. Through this method, the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations can be avoided or reduced. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are unavailable, it can do its best to serve the UE. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0082] Another embodiment of a method for session establishment and handover of the present invention is as Figure 6 described. The detailed description of the steps irrelevant to the present invention is omitted here. The steps include:

[0083] Step 601, the source base station sends a handover request message to the target base station, and the S-NSSAI, configured S-NSSAI, and / or network slice policy information of each PDU session to be established are carried in the message. Among them, the configured S-NSSAI is a conditional information unit and will only appear when the slice resources actually used by the PDU session at the source base station are the resources corresponding to the secondary S-NSSAI.

[0084] The destination base station preferentially configures the resources corresponding to the S-NSSAI of the PDU session for the PDU session requested to be established. If the destination base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI are overloaded or unavailable, the destination base station can select the slice resources that serve the PDU session according to the network slicing policy information. If the network slicing policy information contains multiple auxiliary S-NSSAIs and / or priority information of auxiliary S-NSSAIs, the destination base station selects the resources corresponding to the S-NSSAI with a higher priority. For example, the destination base station can select the S-NSSAI with the highest priority supported by the destination base station in the network slicing policy information. After the selection is successful, the newly selected S-NSSAI will be indicated by the configured S-NSSAI.

[0085] If the destination base station receives the configured S-NSSAI and supports the S-NSSAI of the PDU session, the destination base station will select the slice resources corresponding to the S-NSSAI of the PDU session for the PDU session to ensure that the PDU session always uses the optimal slice resources supported by the network. After successful selection, the destination base station will delete the configured S-NSSAI information in the PDU session context.

[0086] The destination base station saves the network slice information actually configured for the PDU session.

[0087] In step 602, the destination base station sends a handover request confirmation message to the source base station. The message includes a transparent transmitter from the destination to the source. If the network slice resource serving the PDU session is a slice resource corresponding to the configured S-NSSAI, the message will carry information about the configured S-NSSAI of the PDU session.

[0088] In step 603, if after the handover is completed, there are slice resources corresponding to the PDU session that are resources corresponding to the configured S-NSSAI, the source base station sends a handover execution command to the UE through an RRC reconfiguration message, which carries the S-NSSAI configured for the PDU session. The UE saves the S-NSSAI information configured for all PDU sessions. If the UE does not receive the configured S-NSSAI information in the message, the UE knows that the corresponding PDU session will use the slice resources corresponding to the S-NSSAI of the PDU session.

[0089] The UE sends an RRC reconfiguration complete message to the target base station to indicate that the handover is complete.

[0090] In step 604, the destination base station initiates a path switching request to the AMF, which carries the configured S-NSSAI of the PDU session.

[0091] In step 605, the AMF will send the configured S-NSSAI of the PDU session to the SMF via an Update Session Management Context Request message. If the SMF does not receive the configured S-NSSAI information in the message, the SMF knows that the corresponding PDU session uses the slice resources corresponding to the S-NSSAI of the PDU session.

[0092] In step 607, since the slice resources actually used by the PDU session may change. For example, the slice resources actually used by the PDU session change from the resources corresponding to the S-NSSAI of the PDU session to the resources corresponding to the configured S-NSSAI, or from the resources corresponding to the configured S-NSSAI to the resources corresponding to the S-NSSAI of the PDU session. The SMF may reselect a UPF for the PDU session according to the changed S-NSSAI information and execute the UPF selection process.

[0093] Thus, another embodiment of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. Through this method, problems such as service interruption caused by session handover failure when the UE moves or hands over between different base stations can be avoided or reduced. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are unavailable, it can do its best to serve the UE. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0094] Another embodiment of a method for session establishment and handover of the present invention is as Figure 7 described. The detailed description of steps irrelevant to the present invention is omitted here. The steps include:

[0095] In step 701, the source base station sends a handover requirement message to the source AMF. The S-NSSAI, configured S-NSSAI, and / or network slice policy information of each requested PDU session are carried in the message. The configured S-NSSAI is a conditional information unit and will only appear when the slice resources actually used by the PDU session at the source base station are the resources corresponding to the secondary S-NSSAI.

[0096] In step 702, the source AMF sends a Create UE Context Request to the destination AMF. The message contains a handover requirement transparent transmitter from the source base station. The message contains an SM N2 information list, a PDU session identifier list, and UE context information. The UE context information contains a PDU session identifier list, the SMF information corresponding to the PDU session, the S-NSSAI corresponding to the PDU session, and the configured S-NSSAI corresponding to the PDU session.

[0097] In step 703, the destination AMF sends an Update Session Management Context Request message to the SMF. The message includes the S-NSSAI of each PDU session requested to be established during the handover process, the configured S-NSSAI and / or network slice policy information, and the S-NSSAI supported by the destination AMF and the destination base station.

[0098] The SMF preferentially configures resources corresponding to the S-NSSAI of the PDU session for the requested PDU session. If the destination network does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI are overloaded or unavailable, the SMF can select slice resources serving the PDU session according to the network slice policy information. If the network slice policy information contains multiple secondary S-NSSAIs and / or priority information of the secondary S-NSSAIs, the SMF selects the resources corresponding to the S-NSSAI with a higher priority. For example, the SMF can select the S-NSSAI with the highest priority supported by the destination network in the network slice policy information. After successful selection, the newly selected S-NSSAI will be indicated by the configured S-NSSAI. The destination network includes the destination base station and the destination core network.

[0099] If the SMF receives the configured S-NSSAI and the destination network supports the S-NSSAI of the PDU session, the SMF will select the slice resources corresponding to the S-NSSAI of the PDU session for the PDU session to ensure that the PDU session always uses the optimal slice resources supported by the network. After successful selection, the SMF will delete the configured S-NSSAI information in the PDU session context.

[0100] The SMF saves the network slice information actually configured for the PDU session.

[0101] The SMF can reconfigure the network slice policy information. If the SMF reconfigures the network slice policy information of the PDU session and the S-NSSAI of the PDU session is not supported, the SMF selects the configured S-NSSAI for the PDU session according to the updated network slice policy information.

[0102] In step 704, since the slice resources actually used by the PDU session may change. For example, the slice resources actually used by the PDU session change from the resources corresponding to the S-NSSAI of the PDU session to the resources corresponding to the configured S-NSSAI, or from the resources corresponding to the configured S-NSSAI to the resources corresponding to the S-NSSAI of the PDU session. Therefore, according to the changed S-NSSAI information, the SMF may reselect a UPF for the PDU session and execute the UPF selection process.

[0103] In step 705, the SMF sends an updated session management context feedback message to the destination AMF, carrying the updated S-NSSAI, configured S-NSSAI, and / or network slice policy information for each PDU session.

[0104] In step 706, the destination AMF sends a handover request message to the destination base station, carrying the S-NSSAI, configured S-NSSAI, and / or network slice policy information for each PDU session whose establishment is requested. Among them, the configured S-NSSAI is a conditional information unit and will only appear when the slice resources actually used by the PDU session at the source base station are the resources corresponding to the secondary S-NSSAI.

[0105] The destination base station preferentially configures the resources corresponding to the S-NSSAI of the PDU session for the PDU session whose establishment is requested. If the destination base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI are overloaded or unavailable, the destination base station can select the slice resources serving the PDU session according to the network slice policy information. If the network slice policy information contains multiple secondary S-NSSAIs and / or the priority information of the secondary S-NSSAIs, the destination base station selects the resources corresponding to the S-NSSAI with a higher priority. For example, the destination base station can select the S-NSSAI with the highest priority supported by the destination base station in the network slice policy information. After successful selection, the newly selected S-NSSAI will be indicated by the configured S-NSSAI.

[0106] If the destination base station receives the configured S-NSSAI and supports the S-NSSAI of the PDU session, the destination base station will select the slice resources corresponding to the S-NSSAI of the PDU session back for the PDU session to ensure that the PDU session always uses the optimal slice resources supported by the network. After successful selection, the destination base station will delete the configured S-NSSAI information in the PDU session context.

[0107] The destination base station saves the network slice information actually configured for the PDU session.

[0108] In step 707, the destination base station sends a handover request confirmation message to the destination AMF. If the network slice resources serving the PDU session are the network slice resources corresponding to the configured S-NSSAI, the message will carry the configured S-NSSAI information of the PDU session.

[0109] In step 708, the AMF sends the configured S-NSSAI of the PDU session to the SMF via an Update Session Management Context Request message. If the SMF does not receive the configured S-NSSAI information in the message, the SMF knows that the corresponding PDU session uses the slice resources corresponding to the S-NSSAI of the PDU session.

[0110] In step 709, since the slice resources actually used by the PDU session may change. For example, the slice resources actually used by the PDU session change from the resources corresponding to the S-NSSAI of the PDU session to the resources corresponding to the configured S-NSSAI, or from the resources corresponding to the configured S-NSSAI to the resources corresponding to the S-NSSAI of the PDU session. Therefore, the SMF may reselect a UPF for the PDU session according to the changed S-NSSAI information and execute the UPF selection process.

[0111] In step 710, the SMF sends an Update Session Management Context Response message to the destination AMF.

[0112] If the network slice resources actually configured for the PDU session are the resources corresponding to the configured S-NSSAI, the destination AMF can inform the source AMF via a Create UE Context Response message (step 711). The source AMF can inform the source base station via a Handover Command message (step 712), and the source base station can then inform the UE via an RRC Reconfiguration message (step 713). The configured S-NSSAI of the PDU session successfully established after the handover is carried in the messages.

[0113] The UE saves all the configured S-NSSAI information of the PDU sessions.

[0114] If the UE does not receive the configured S-NSSAI information in the message, the UE knows that the corresponding PDU session will use the slice resources corresponding to the S-NSSAI of the PDU session.

[0115] Thus, the description of another embodiment of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. By this method, it is possible to avoid or reduce the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations. At the same time, during the process of UE movement or handover, the network can always preferentially configure the ongoing sessions to the most suitable resources. When the most suitable resources are unavailable, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU sessions of the UE.

[0116] Another exemplary method for session establishment and handover of the present invention is as Figure 8 described. The detailed description of the steps irrelevant to the present invention is omitted here. This method includes the steps:

[0117] In step 801, the UE sends a message to the first node to request PDU session establishment. The message contains the single network slice selection assistance information (S-NSSAI) of the requested PDU session and also contains network slice policy information. When the network does not support the S-NSSAI of the PDU session or the S-NSSAI of the PDU session is overloaded or unavailable, the network allocates resources for the PDU session considering the network slice policy information. The network slice policy information may be a secondary S-NSSAI, and the secondary S-NSSAI may be one or more. For each PDU session, the secondary S-NSSAI may be one or more. When there are multiple secondary S-NSSAIs, the multiple secondary S-NSSAIs may have different priorities. For example, the S-NSSAI ranked earlier may have a higher priority. The network gives priority to the resources corresponding to the S-NSSAI with a higher priority when allocating resources.

[0118] The UE determines the network slice policy information according to the UE's subscription information, the type of service, the S-NSSAI supported by the UE, etc.

[0119] The first node may be a core network node or a base station. The second node may be a base station or a core network node. The core network node may be an SMF or an AMF.

[0120] In step 802, the first node sends a message to the second node to request PDU session establishment.

[0121] The specific description in step 301 also applies to this method and will not be repeated here. It should be noted that the first node (such as a core network node) may send the network handover policy information received from the UE to the second node, or the first node determines the network slice policy information considering the network slice policy information received from the UE, the network slice selection policy (NSSP), the UE's subscription information, the quality of service (Qos) information of the service, the S-NSSAI supported by the AMF, and / or the S-NSSAI supported by the SMF, etc.

[0122] Step 803 is the same as step 302 and will not be repeated here.

[0123] The method may further include the steps:

[0124] The second node sends the S-NSSAI actually configured for the PDU session to the core network. Based on the S-NSSAI actually configured for the UE, the core network can reselect the session management function entity and / or user plane function entity of the PDU session for the UE. For example, the base station sends the S-NSSAI actually configured for the PDU session to the AMF, and the AMF reselects the SMF and / or UPF for the PDU session of the UE. Or the base station sends the S-NSSAI actually configured for the PDU session to the SMF, and the SMF reselects the UPF for the PDU session of the UE.

[0125] It should be noted that when this method is used for handover, step 801 is not required.

[0126] When this method is used for handover and the second base station (target base station) does not support the S-NSSAI of a certain PDU session and configures the resources of another network slice for the PDU session according to the network slice policy information. When the second base station triggers the handover of the UE to the third base station, as described in step 802, the handover request message includes the S-NSSAI of the PDU session and the network slice policy information. If the third base station supports the S-NSSAI of the PDU session, the third base station configures the PDU session on the resources corresponding to the S-NSSAI. This method can ensure that the most suitable resources are always configured for the PDU session of the UE.

[0127] When this method is only used for handover, when the source base station triggers the handover of the UE to the target base station, the message described in step 802 is used as the handover request message, which includes the S-NSSAI of the PDU session and the network slice policy information; if the resources actually configured by the source base station for the PDU session are the resources corresponding to the configured S-NSSAI of the PDU session selected based on the network slice policy information, the handover request message may include the configured S-NSSAI. If the target base station supports the S-NSSAI of the PDU session, it configures the PDU session on the resources corresponding to the S-NSSAI of the PDU session. If the target base station does not support the S-NSSAI of a certain PDU session or the S-NSSAI of the PDU session is overloaded or unavailable, it configures other network slice resources for the PDU session according to the network slice policy information. This method can ensure that the most suitable resources are always configured for the PDU session of the UE.

[0128] So far, the description of another exemplary method for PDU session establishment and another exemplary method for handover of the present invention has been completed. Through this method, it is possible to avoid or reduce the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are not available, it can do its best to serve the UE. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE. An embodiment of a method for session establishment and handover of the present invention is as follows Figure 9 described. The detailed description of the steps irrelevant to the present invention is omitted here. The steps include:

[0129] In step 901, the UE determines the network slice policy information according to the NSSP, the UE's subscription information, the service type, and / or the allowed NSSAI of the UE, etc. The network slice policy information may be a secondary S-NSSAI, and the secondary S-NSSAI may be one or more. For each PDU session, the secondary S-NSSAI may be one or more. When there are multiple secondary S-NSSAIs, the multiple secondary S-NSSAIs may have different priorities. For example, the S-NSSAI ranked in the front may have a higher priority.

[0130] In step 902, the UE sends a PDU session establishment request message to the AMF. The message includes a PDU session identifier, one or more S-NSSAIs, network slice policy information, and an N1 session management (SM) container. The S-NSSAI is among the allowed NSSAIs of the current access type.

[0131] In step 903, the AMF may update the network slice policy information according to the base station serving the UE and / or the S-NSSAI situation supported by the AMF and / or the SMF and local configuration, etc. For example, the secondary S-NSSAI information therein may be updated to ensure that the S-NSSAIs in the network slice policy information are all supported by the AMF and the base station.

[0132] When the AMF selects an SMF, if it needs to query the NSSF and the NRF, it may carry the network slice policy information in the network slice selection acquisition process between the AMF and the NSSF and the network function discovery request process between the AMF and the NRF, so as to select a more suitable SMF. When multiple SMFs all support the S-NSSAI of the requested PDU session, the SMF that supports the most secondary S-NSSAIs in the network slice policy information may be selected.

[0133] The AMF saves the S-NSSAI associated with the PDU session and the network slice policy information.

[0134] In step 904, the AMF sends a Create Session Management Context Request message to the selected SMF, and the network slice policy information for each PDU session requested from the SMF may be carried in the message. If the SMF does not support the S-NSSAI in the network slice policy, the SMF will update the network slice policy information to ensure that the S-NSSAI in the network slice policy information are all supported by the SMF.

[0135] In step 905, the SMF sends a Create Session Management Context Response message to the AMF, and the updated network slice policy information for each PDU session managed by the SMF is included in the message. The AMF saves the updated network slice policy information.

[0136] In step 906, the AMF sends an Initial Context Setup Request or PDU Session Resource Setup Request message to the base station, and the S-NSSAI and network slice policy information for the PDU session to be established are carried in the message.

[0137] For the PDU session to be established, the base station preferentially configures resources corresponding to the S-NSSAI of the PDU session for the requested PDU session. If the base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI of the PDU session are overloaded or unavailable, the base station may select the S-NSSAI serving the PDU session according to the network slice policy information. The base station may select the S-NSSAI supported by the base station with a higher priority in the network slice policy information. The S-NSSAI selected by the base station from the network slice policy information is the configured S-NSSAI, which belongs to the conditional information unit and only exists when the network slice resources corresponding to the S-NSSAI of the PDU session are not supported, overloaded or unavailable. When the network slice policy information is the secondary S-NSSAI, the base station selects the configured S-NSSAI from the secondary S-NSSAI. The base station saves the S-NSSAI, configured S-NSSAI and network slice policy information of all PDU sessions.

[0138] In step 907, the base station sends an RRC Reconfiguration message to the UE. The message contains a NAS message indicating the completion of the PDU session establishment, which carries the S-NSSAI and configured S-NSSAI of each PDU session. If the configured S-NSSAI appears, it means that the network slice resources used for the corresponding PDU session are not the slice resources corresponding to the S-NSSAI of the PDU session, but the slice resources corresponding to the secondary S-NSSAI.

[0139] After receiving the message, the UE saves the S-NSSAI and configured S-NSSAI information associated with all PDU sessions.

[0140] In step 908, the base station sends an initial context establishment response or a PDU session resource establishment response message to the AMF, and the configured S-NSSAI of the PDU session may be carried in the message. In step 909, if the configured S-NSSAI is carried in the message, the AMF will carry the configured S-NSSAI in the update session management context request sent to the SMF. In step 910, the SMF may reselect a UPF for the PDU session according to the configured S-NSSAI and perform a UPF selection process.

[0141] So far, a description of an embodiment of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. By this method, the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations can be avoided or reduced. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are unavailable, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0142] Another embodiment of a method for session establishment and handover of the present invention is as Figure 10 described. The detailed description of steps irrelevant to the present invention is omitted here. The steps include:

[0143] In step 1001, the UE sends a PDU session establishment request message to the AMF. The message includes a PDU session identifier, one or more S-NSSAIs, network slice policy information, and an N1 session management (SM) container. The S-NSSAI is among the allowed NSSAIs of the current access type.

[0144] The UE determines the network slice policy information according to NSSP, the UE's subscription information, the service type, and / or the allowed NSSAI of the UE, etc. The network slice policy information may be a secondary S-NSSAI, and the secondary S-NSSAI may be one or more. For each PDU session, the secondary S-NSSAI may be one or more. When there are multiple secondary S-NSSAIs, the multiple secondary S-NSSAIs may have different priorities. For example, the S-NSSAI ranked in the front may have a higher priority.

[0145] In step 1002, the AMF sends a create session management context request message to the SMF, and information such as NSSP, the UE's subscription information, the allowed NSSAI, and / or the supported S-NSSAI of the network serving the UE may be carried in the message. The network includes the core network and the base station.

[0146] In step 1003, the SMF may update the network slice policy information for each requested PDU session based on the NSSP, the UE's subscribed information, QoS information, the permitted NSSAI, the supported S-NSSAI of the network serving the UE, and / or local configuration, etc., to ensure that the S-NSSAI in the network slice policy information is supported by the network. The SMF stores the S-NSSAI and network slice policy information of the PDU session.

[0147] In step 1004, the SMF sends a create session management context feedback message to the AMF, which contains the S-NSSAI and network slice policy information of each PDU session managed by the SMF. The network slice information is the network slice policy information received from the UE or updated by the SMF. The AMF stores the received network slice policy information.

[0148] In step 1005, the AMF initiates an initial context setup request or a PDU session resource setup request message to the base station, which carries the S-NSSAI and network slice policy information for the PDU session to be established.

[0149] For the PDU session to be established, the base station preferentially configures the resources corresponding to the S-NSSAI of the PDU session for the requested PDU session. If the base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI of the PDU session are overloaded or unavailable, the base station may select the S-NSSAI serving the PDU session according to the network slice policy information. The base station may select the S-NSSAI supported by the base station with a higher priority in the network slice policy information. The S-NSSAI selected by the base station from the network slice policy information is the configured S-NSSAI, which belongs to the conditional information unit and only exists when the network slice resources corresponding to the S-NSSAI of the PDU session are not supported or overloaded or unavailable. When the network slice policy information is the secondary S-NSSAI, the base station selects the configured S-NSSAI from the secondary S-NSSAI.

[0150] The base station stores the S-NSSAI, configured S-NSSAI, and network slice policy information of all PDU sessions.

[0151] In step 1006, the base station sends an RRC reconfiguration message to the UE. The message contains the NAS message indicating the completion of the PDU session establishment, which carries the S-NSSAI, configured S-NSSAI, and network slice policy information of each PDU session. If the configured S-NSSAI appears, it means that the network slice resources used for the corresponding PDU session are not the slice resources corresponding to the S-NSSAI of the PDU session, but the slice resources corresponding to the secondary S-NSSAI.

[0152] After receiving the message, the UE saves the S-NSSAI of all PDU sessions and the configured S-NSSAI information.

[0153] In step 1007, the base station sends an initial context establishment response or a PDU session resource establishment response message to the AMF. The configured S-NSSAI of the PDU session may be carried in the message. If the configured S-NSSAI is carried in the message, the AMF will carry the configured S-NSSAI in the update session management context request sent to the SMF (step 1008). The SMF may reselect a UPF for the PDU session according to the configured S-NSSAI and execute the UPF selection process (step 1009).

[0154] Thus, the description of another embodiment of an exemplary method for PDU session establishment and an exemplary method for handover according to the present invention is completed. By this method, the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations can be avoided or reduced. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are unavailable, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0155] Another exemplary method for session establishment and handover according to the present invention is as Figure 11 described. The detailed description of steps irrelevant to the present invention is omitted here. This method includes the steps:

[0156] In step 1101, the first node receives a message for requesting PDU session establishment from the second node. The message includes the S-NSSAI of the PDU session to be configured.

[0157] The first node may be a base station or a core network node. The second node may be a core network node or a base station. The core network node may be an SMF or an AMF. As an example, the message received by the first node from the second node may be sent by the core network node as the second node to the base station as the first node, sent by the first base station as the second node to the second base station as the first node (e.g., sent by the source base station to the destination base station), sent by the first core network node as the second node to the second core network node as the first node (e.g., sent by the source core network node to the destination core network node), or sent by the base station as the first node to the core network node as the second node. According to the specific implementation manners of the first node and the second node, the message may be, for example, an initial UE context establishment request message (when the first node is a base station and the second node is a core network node), a PDU session resource establishment request message (when the first node is a base station and the second node is a core network node), a handover request message (when the first node is the destination base station and the second node is the core network node or the first node is the destination base station and the second node is the source base station), a handover requirement message (when the first node is the source core network node and the second node is the source base station), a path switch request confirmation message (when the first node is the destination base station and the second node is the core network node), or a create UE context request message (when the first node is the destination core network node and the second node is the source core network node), etc. The above examples are only for illustration and not for limitation.

[0158] When the method is used for handover, the message requesting PDU session establishment further includes the S-NSSAI actually configured for the PDU session.

[0159] In step 1102, the first node receives a message for session establishment request. The first node saves the received PDU session information, including the S-NSSAI of the PDU session.

[0160] The first node considers the S-NSSAI in the message when allocating resources for the requested PDU session. When the first node or the cell of the first node does not support the S-NSSAI, the first node configures other available network slice resources for the PDU session. The first node selects resources of a suitable network slice according to the QoS parameters of the QoS flow in the PDU session, the network slices supported by the base station and / or AMF and / or SMF serving the UE, and / or the configuration of network operation and maintenance (O&M), etc.

[0161] The method may further include the step of:

[0162] The first node sends the S-NSSAI actually configured for the PDU session to the core network. Based on the S-NSSAI actually configured for the UE, the core network can reselect the session management function entity and / or user plane function entity of the PDU session for the UE. For example, the base station sends the S-NSSAI actually configured for the PDU session to the AMF, and the AMF reselects the SMF and / or UPF for the PDU session of the UE. Or the base station sends the S-NSSAI actually configured for the PDU session to the SMF, and the SMF reselects the UPF for the PDU session of the UE.

[0163] When this method is used for handover and the second base station (target base station) does not support the S-NSSAI of a certain PDU session and configures resources of another network slice for the PDU session. When the second base station triggers the handover of the UE to the third base station, as described in step 1101, the handover request message includes the S-NSSAI of the PDU session and the S-NSSAI actually configured for the PDU session. If the third base station supports the S-NSSAI of the PDU session, the third base station configures the PDU session on the resources corresponding to the S-NSSAI of the PDU session. This method can ensure that the most suitable resources are always configured for the PDU session of the UE.

[0164] When this method is only used for handover, when the source base station triggers the handover of the UE to the target base station, the message described in step 1101 is used as the handover request message, which may include the S-NSSAI of the PDU session; if the resources actually configured by the source base station for the PDU session are the resources corresponding to the S-NSSAI configured for the reselected PDU session, the handover request message may include the configured S-NSSAI. If the target base station supports the S-NSSAI of the PDU session, it configures the PDU session on the resources corresponding to the S-NSSAI of the PDU session. If the target base station does not support the S-NSSAI of a certain PDU session or the S-NSSAI of the PDU session is overloaded or unavailable, it reselects other network slice resources for the PDU session. This method can ensure that the most suitable resources are always configured for the PDU session of the UE. Thus, the description of another exemplary method for PDU session establishment and handover of the present invention is completed. Through this method, the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations can be avoided or reduced. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources, and when the most suitable resources are unavailable, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0165] An embodiment of a method for session establishment and handover of the present invention is as followsFigure 12 As described above. The detailed description of steps unrelated to the present invention is omitted here. The steps include:

[0166] In step 1201, the AMF sends an initial context establishment request or a PDU session resource establishment request message to the base station, and the S-NSSAI for establishing the PDU session and the QoS parameters of the QoS flow are carried in the message.

[0167] It should be noted that there are two types of S-NSSAI involved in the present invention. One is the S-NSSAI of the PDU session. The S-NSSAI of the PDU session is the S-NSSAI corresponding to the PDU session identifier included in the N2 SM information sent by the core network to the base station during the PDU session establishment process in the current 3GPP specification 23.502, or the S-NSSAI of the PDU session is the S-NSSAI corresponding to the PDU session identifier sent by the UE to the core network during the PDU session establishment process in the current 3GPP specification 23.502; the second is the S-NSSAI actually configured for the PDU session by the base station according to the supported slice information, resource conditions, and / or network operation and maintenance (O&M) configurations, etc., hereinafter referred to as the configured S-NSSAI.

[0168] For the PDU session to be established, the base station preferentially configures resources corresponding to the S-NSSAI of the PDU session for the requested PDU session establishment. If the base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI of the PDU session are overloaded or unavailable, the base station can select the S-NSSAI serving the PDU session. The base station can select the S-NSSAI serving the PDU session according to the QoS parameters of the QoS flow in the PDU session, the S-NSSAI supported by the base station and / or AMF and / or SMF serving the UE, and / or network operation and maintenance (O&M) configurations, etc. The selected S-NSSAI is the configured S-NSSAI, which belongs to the conditional information unit and is only used when the slice resources configured for the PDU session are not the slice resources corresponding to the S-NSSAI of the PDU session but the slice resources corresponding to the reselected configured S-NSSAI.

[0169] The base station stores the S-NSSAI information of all PDU sessions and the configured S-NSSAI information.

[0170] In step 1202, the base station sends a Radio Resource Management (RRC) reconfiguration message to the UE. The message contains the NAS message indicating the completion of PDU session establishment, which carries the S-NSSAI of each PDU session and the configured S-NSSAI. If the configured S-NSSAI appears, it means that the network slice resources used for the corresponding PDU session are not the slice resources corresponding to the S-NSSAI of the originally configured PDU session, but the slice resources corresponding to the reselected configured S-NSSAI, and will be used only when this is the case.

[0171] After receiving the message, the UE saves the S-NSSAI of all PDU sessions and the configured S-NSSAI information.

[0172] In step 1203, the base station sends an initial context establishment response or a PDU session resource establishment response message to the AMF. The configured S-NSSAI of the PDU session may be carried in the message. If the configured S-NSSAI is carried in the message, the AMF will carry the configured S-NSSAI in the update session management context request sent to the SMF (step 1204), and the SMF may reselect a UPF for the PDU session according to the configured S-NSSAI and perform the UPF selection process (step 1205). If the SMF does not receive the configured S-NSSAI information in the message, the SMF knows that the corresponding PDU session uses the slice resources corresponding to the S-NSSAI of the PDU session.

[0173] So far, a description of an embodiment of an exemplary method for PDU session establishment and an exemplary method for handover according to the present invention is completed. Through this method, it is possible to avoid or reduce the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are not available, it can do its best to serve the UE. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0174] Another embodiment of a method for session establishment and handover according to the present invention is as Figure 13 described. The detailed description of steps irrelevant to the present invention is omitted here. The steps include:

[0175] In step 1301, the source base station initiates a handover request message to the target base station, and information such as the S-NSSAI of each PDU session requested, the configured S-NSSAI, and the QoS parameters of the QoS flow is carried in the message. Among them, the configured S-NSSAI is a conditional information unit and is only used when the slice resources actually used by the PDU session at the source base station are not the slice resources corresponding to the S-NSSAI of the PDU session, but the slice resources corresponding to the reselected configured S-NSSAI.

[0176] The target base station preferentially configures resources corresponding to the S-NSSAI of the PDU session for the requested established PDU session. If the target base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI are overloaded or unavailable, the target base station selects resources of a network slice corresponding to a suitable S-NSSAI. The target base station can select resources of a network slice corresponding to a suitable S-NSSAI according to the QoS parameters of the QoS flow in the PDU session, the S-NSSAIs supported by the target base station and the target AMF, and / or the configuration of network operation and maintenance (O&M). After successful selection, the newly selected S-NSSAI will be indicated by the configured S-NSSAI.

[0177] If the target base station receives the configured S-NSSAI, and the target base station supports the S-NSSAI of the PDU session, the target base station will select back the slice resources corresponding to the S-NSSAI of the PDU session for the PDU session to ensure that the PDU session always uses the optimal slice resources supported by the network. After successful selection, the target base station will delete the configured S-NSSAI information in the PDU session context.

[0178] The target base station saves the network slice information actually configured for the PDU session.

[0179] In step 1302, the target sends a handover request confirmation message. The message includes a transparent transmitter from the target to the source.

[0180] In step 1303, if after the handover is completed, the slice resources corresponding to a PDU session are the resources corresponding to the configured S-NSSAI, the source base station sends a handover execution command to the UE through an RRC reconfiguration message, which carries the configured S-NSSAI of the PDU session. The UE saves all the configured S-NSSAI information of the PDU session. If the UE does not receive the configured S-NSSAI information in the message, the UE knows that the corresponding PDU session will use the slice resources corresponding to the S-NSSAI of the PDU session.

[0181] In step 1304, the UE sends an RRC reconfiguration complete message to the target base station to indicate that the handover is completed.

[0182] In step 1305, the destination base station sends a path conversion request to the AMF, carrying the configured S-NSSAI of the PDU session.

[0183] In step 1306, the AMF sends the configured S-NSSAI of the PDU session to the SMF via an update session management context request message. If the SMF does not receive the configured S-NSSAI information in the message, the SMF knows that the corresponding PDU session uses the slice resources corresponding to the S-NSSAI of the PDU session.

[0184] Since the slice resources actually used by the PDU session may change. For example, the slice resources actually used by the PDU session change from the resources corresponding to the S-NSSAI of the PDU session to the resources corresponding to the configured S-NSSAI, or from the resources corresponding to the configured S-NSSAI to the resources corresponding to the S-NSSAI of the PDU session. In step 1307, the SMF may reselect a UPF for the PDU session according to the changed S-NSSAI information and execute the UPF selection process.

[0185] Thus, the description of another embodiment of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. Through this method, it is possible to avoid or reduce the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are not available, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0186] Another embodiment of a method for session establishment and handover of the present invention is as Figure 14 described. The detailed description of steps irrelevant to the present invention is omitted here. The steps include:

[0187] In step 1401, the source base station sends a handover requirement message to the source AMF. The message carries information such as the S-NSSAI of each requested PDU session, the configured S-NSSAI, and the QoS parameters of the QoS flow. Among them, the configured S-NSSAI is a conditional information unit and will only appear when the slice resources actually used by the PDU session at the source base station are not the resources corresponding to the S-NSSAI of the initially configured PDU session but the reconfigured S-NSSAI.

[0188] In step 1402, the source AMF sends a Create UE Context Request to the destination AMF, and the message contains a handover requirement transparent transmitter from the source base station. The message contains a list of SM N2 information, a list of PDU session identifiers, and UE context information. The UE context information contains a list of PDU session identifiers, SMF information corresponding to the PDU session, S-NSSAI corresponding to the PDU session, and configured S-NSSAI corresponding to the PDU session.

[0189] In step 1403, the destination AMF sends an Update Session Management Context Request message to the SMF, and the message includes the S-NSSAI, configured S-NSSAI, and / or QoS parameters of each QoS flow requested to be established during the handover process, and the supported S-NSSAI of the destination network. The destination network includes the destination core network and the destination base station.

[0190] The SMF preferentially configures resources corresponding to the S-NSSAI of the PDU session for the PDU session requested to be established. If the destination network does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI are overloaded or unavailable, the SMF can reselect resources of the network slice corresponding to a suitable S-NSSAI according to the QoS parameters of the QoS flow in the PDU session, the base station serving the UE, and / or the network slices supported by the AMF and / or SMF, and / or the configuration of network operation and maintenance (O&M), etc. After successful selection, the newly selected S-NSSAI will be indicated by the configured S-NSSAI. The destination network is the destination core network and the destination base station.

[0191] If the SMF receives the configured S-NSSAI and the destination network supports the S-NSSAI of the PDU session, the SMF will select back the slice resources corresponding to the S-NSSAI of the PDU session for the PDU session to ensure that the PDU session always uses the optimal slice resources supported by the network. After successful selection, the SMF will delete the configured S-NSSAI information in the PDU session context.

[0192] The SMF saves the network slice information actually configured for the PDU session.

[0193] In step 1404, since the slice resources actually used by the PDU session may change, for example, the slice resources actually used by the PDU session change from the resources corresponding to the S-NSSAI of the PDU session to the resources corresponding to the configured S-NSSAI, or from the resources corresponding to the configured S-NSSAI to the resources corresponding to the S-NSSAI, the SMF may reselect a UPF for the PDU session according to the changed S-NSSAI information and execute the UPF selection process.

[0194] In step 1405, the SMF sends an updated session management context feedback message to the destination AMF, carrying the updated S-NSSAI of each PDU session and the configured S-NSSAI.

[0195] In step 1406, the destination AMF sends a handover request message to the destination base station, carrying the S-NSSAI, the configured S-NSSAI, and QoS parameters of each PDU session for which establishment is requested. Among them, the configured S-NSSAI is a conditional information element and will only appear when the slice resources actually used by the PDU session at the source base station are the resources corresponding to the configured S-NSSAI.

[0196] The destination base station preferentially configures resources corresponding to the S-NSSAI of the PDU session for the PDU session for which establishment is requested. If the destination base station does not support the S-NSSAI of the PDU session or the slice resources corresponding to the S-NSSAI are overloaded or unavailable, the destination base station can re-select resources of a network slice corresponding to a suitable S-NSSAI according to the QoS parameters of the QoS flow in the PDU session, the S-NSSAIs supported by the destination base station and the destination AMF, and / or the configuration of network operation and maintenance (O&M), etc. After successful selection, the newly selected S-NSSAI will be indicated by the configured S-NSSAI.

[0197] If the destination base station receives the configured S-NSSAI and supports the S-NSSAI of the PDU session, the destination base station will select back the slice resources corresponding to the S-NSSAI of the PDU session for the PDU session to ensure that the PDU session always uses the optimal slice resources supported by the network. After successful selection, the destination base station will delete the configured S-NSSAI information in the PDU session context.

[0198] The destination base station saves the network slice information actually configured for the PDU session.

[0199] In step 1407, the destination base station sends a handover request confirmation message to the destination AMF. If the network slice resources serving the PDU session are the network slice resources corresponding to the configured S-NSSAI, the message will carry the configured S-NSSAI information of the PDU session.

[0200] In step 1408, the AMF sends the configured S-NSSAI of the PDU session to the SMF via an Update Session Management Context Request message. If the SMF does not receive the configured S-NSSAI information in the message, the SMF knows that the corresponding PDU session uses the slice resources corresponding to the S-NSSAI of the PDU session. In step 1409, since the slice resources actually used by the PDU session may change. For example, the slice resources actually used by the PDU session change from the resources corresponding to the S-NSSAI of the PDU session to the resources corresponding to the configured S-NSSAI, or from the resources corresponding to the configured S-NSSAI to the resources corresponding to the S-NSSAI of the PDU session. Therefore, the SMF may reselect a UPF for the PDU session according to the changed S-NSSAI information and perform a UPF selection process.

[0201] In step 1410, the SMF sends Update Session Management Context Feedback information to the destination AMF.

[0202] In step 1411, if the network slice resources actually configured for the PDU session are the resources corresponding to the configured S-NSSAI, the destination AMF can inform the source AMF via a Create UE Context Feedback message, and the source AMF can inform the source base station via a Handover Command message (step 1412), and the source base station then informs the UE via an RRC Reconfiguration message (step 1413). The configured S-NSSAI of the PDU session successfully established after the handover is carried in the messages.

[0203] The UE saves all the configured S-NSSAI information of the PDU sessions.

[0204] If the UE does not receive the configured S-NSSAI information in the message, the UE knows that the corresponding PDU session will use the slice resources corresponding to the S-NSSAI of the PDU session.

[0205] Thus, another embodiment description of an exemplary method for PDU session establishment and an exemplary method for handover of the present invention is completed. By this method, the problem of service interruption caused by session handover failure when the UE moves or hands over between different base stations can be avoided or reduced. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing sessions to the most suitable resources. When the most suitable resources are unavailable, it can serve the UE to the greatest extent. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU sessions of the UE.

[0206] Figure 15 Another exemplary method for PDU session establishment and handover according to an embodiment of the present disclosure is shown. The method includes steps:

[0207] Step 1501, the first entity sends one or more slice information of each frequency band it supports to the second entity. The first entity may also send one or more slice information of the cell it serves to the second entity. The first entity may further send one or more slice information of each frequency band of the cell it serves to the second entity.

[0208] The first entity may be a base station or a base station distribution unit (gNB-DU).

[0209] The slice information may be S-NSSAI.

[0210] The first entity may send the information to the second entity through an Xn establishment request or an X2 establishment request or a base station configuration update request message or an F1 establishment request.

[0211] Based on the received network handover information, the second entity knows the network slices supported by the first entity's cell or frequency band, and thus can decide whether to configure resources for the UE through the first entity, such as switching the UE to the first entity or configuring the first entity as a secondary base station serving the UE or configuring the UE to a cell on the first entity.

[0212] Step 1502, the second entity sends a response message to the first entity.

[0213] The second entity may send one or more slice information of each frequency band it supports to the first entity through the response message. The second entity may also send one or more slice information of the cell it serves to the first entity. The second entity may further send one or more slice information of each frequency band of the cell it serves to the first entity.

[0214] The second entity may be another base station or a base station central unit (gNB-CU).

[0215] The slice information may be S-NSSAI.

[0216] The response message may be an Xn establishment response or an X2 establishment response or a base station configuration update confirmation or an F1 establishment response message.

[0217] Based on the received network handover information, the first entity knows the network slices supported by the second entity's cell or frequency band, and thus can decide whether to configure resources for the UE through the second entity, such as switching the UE to the second entity or configuring the second entity as a secondary base station serving the UE.

[0218] So far, the description of another exemplary method of the present invention for PDU session establishment and handover has been completed. Through this method, it is possible to know the network slices supported by each frequency point or each cell of the neighboring base station or gNB-DU, so that appropriate resources can be better configured for the UE, avoiding resource configuration or handover failures, and avoiding or reducing the problem of service interruption caused by session handover failures when the UE moves or hands over between different base stations. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources.

[0219] So far, the description of the PDU session establishment method and handover method of the present invention has been completed. Through this method, it is possible to avoid or reduce the problem of service interruption caused by session handover failures when the UE moves or hands over between different base stations. At the same time, during the movement or handover of the UE, the network can always preferentially configure the ongoing session to the most suitable resources. When the most suitable resources are unavailable, it can do its best to serve the UE. And after multiple handovers, it can also ensure that the most suitable resources are always configured for the PDU session of the UE.

[0220] According to one aspect of the present invention, there is provided a method and apparatus for session establishment and handover in a wireless communication system. The method includes: receiving, by a first node, a message from a second node, the message including a single network slice selection assistance resource (S-NSSAI) of a PDU session; and allocating, by the first node, resources for the PDU session based on the message received from the second node, wherein when the first node supports the S-NSSAI of the PDU session, it allocates resources corresponding to the S-NSSAI of the PDU session for the PDU session; and when the first node does not support the S-NSSAI or the resources corresponding to the S-NSSAI are unavailable or overloaded, the first node allocates other available resources for the PDU session.

[0221] According to another aspect of the present invention, a base station in a wireless communication system includes: a transceiver configured to receive or transmit signals; and at least one processor configured to receive a message from a second node, the message including a single network slice selection assistance resource (S-NSSAI) of a PDU session; and allocate resources for the PDU session based on the message received from the second node, wherein when the base station supports the S-NSSAI of the PDU session, it allocates resources corresponding to the S-NSSAI of the PDU session for the PDU session; and when the base station does not support the S-NSSAI or the resources corresponding to the S-NSSAI are unavailable or overloaded, the base station allocates other available resources for the PDU session.

[0222] According to another aspect of the present invention, a core network node in a wireless communication system includes: a transceiver configured to receive or transmit signals; and at least one processor configured to receive a message from a second node, the message including a single network slice selection assistance resource (S-NSSAI) of an initially allocated PDU session; and allocate resources for the PDU session based at least in part on the message received from the second node, wherein when the core network node supports the S-NSSAI of the PDU session, it allocates network slice resources corresponding to the S-NSSAI of the PDU session for the PDU session; and when the core network node does not support the S-NSSAI or the network slice resources corresponding to the S-NSSAI are unavailable or overloaded, the core network node allocates other available network slice resources for the PDU session.

[0223] In one embodiment, the message received by the first node from the second node includes at least one of an initial UE context establishment request message received by a base station from a core network node, a PDU session resource establishment request message received by a base station from a core network node, a handover request message received by a target base station from a core network node, a path switch request confirmation message received by a target base station from a core network node, a handover request message received by a target base station from a source base station, a handover requirement message received by a source core network node from a source base station, and a create UE context request message received by a target core network node from a source core network node.

[0224] In one embodiment, the first node also allocates the other available network slice resources for the PDU session based on QoS parameters of QoS flows in the PDU session, network slice resources supported by a base station serving the UE, and / or configurations of network operation and maintenance (O&M).

[0225] In one embodiment, the first node is a base station or a core network node, and the second node is a core network node or a base station.

[0226] In one embodiment, the core network node includes a session management function entity (SMF) or an access control and mobility management function entity (AMF).

[0227] In one embodiment, the message received by the first node from the second node includes network slice policy information, and the first node allocates the other available resources for the PDU session based on the network slice policy information. In one embodiment, the network slice policy information includes one or more secondary S-NSSAIs.

[0228] In one embodiment, the network slice policy information includes multiple secondary S-NSSAIs with different priorities, and the first node gives priority to the resources corresponding to the secondary S-NSSAIs with higher priorities when allocating resources.

[0229] In one embodiment, the network slice policy information is generated or updated by the AMF or the SMF.

[0230] In one embodiment, the network slice policy information is based on the network slice policy information received from the user equipment (UE).

[0231] In one embodiment, the network slice policy information is generated or updated based on the network slice selection policy (NSSP), the subscription information of the UE, the quality of service (QoS) information of the service, and the S-NSSAIs supported by the base station serving the UE.

[0232] In one embodiment, the S-NSSAI corresponding to the actually configured other available resources is sent to the core network node.

[0233] In one embodiment, the SMF and / or the user plane function entity (UPF) for the PDU session of the UE is reselected according to the actually configured S-NSSAI.

[0234] In one embodiment, when there are multiple SMFs that support the S-NSSAI of the PDU session, the SMF that supports the most secondary S-NSSAIs in the network slice policy information is selected.

[0235] In one embodiment, if the SMF does not support the S-NSSAI in the network slice policy, the SMF will update the network slice policy information to ensure that all the S-NSSAIs in the network slice policy are supported by the SMF.

[0236] In one embodiment, when the method is used for handover, the S-NSSAI corresponding to the actually configured other available resources is included in the message received by the first node from the second node.

[0237] In one embodiment, when the method is used for handover, if the first node supports the S-NSSAI of the PDU session, it selects the resources corresponding to the S-NSSAI of the PDU session for the PDU session and deletes the actually configured S-NSSAI in the PDU session context.

[0238] The methods described in the claims and / or the specification according to various embodiments can be implemented by hardware, software, or a combination of hardware and software.

[0239] When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) can be provided. One or more programs stored in the computer-readable storage medium can be configured to be run by one or more processors within the electronic device. At least one program can include instructions that cause the electronic device to perform the methods according to various embodiments of the present disclosure as defined by the appended claims and / or disclosed herein.

[0240] The program (software module or software) can be stored in non-volatile memories, including random access memory (RAM) and flash memory, read-only memory (ROM), electrically erasable programmable ROM (EEPROM), magnetic disk storage devices, compact disk-ROM (CD-ROM), digital versatile disk (DVD), or other types of optical storage devices, or magnetic tape cartridges. Alternatively, any combination of some or all of them can form the memory storing the program. In addition, multiple such memories can be included in the electronic device.

[0241] In addition, the program can be stored in an attachable storage device, and the attachable storage device can access the electronic device through a communication network such as the Internet, intranet, local area network (LAN), wide LAN (WLAN), and storage area network (SAN), or a combination thereof. Such a storage device can access the electronic device implementing various embodiments of the present disclosure via an external port. In addition, a separate storage device on the communication network can access the portable electronic device.

[0242] In the above detailed various embodiments of the present disclosure, according to the presented detailed embodiments, the components included in the present disclosure are represented in singular or plural. However, the selection of the singular form or the plural form is for ease of description, suitable for the presented situation, and the various embodiments of the present disclosure are not limited to its single element or multiple elements. In addition, multiple elements described can be configured into a single element, or a single element described can be configured into multiple elements.

[0243] Although the present disclosure has been shown and described with reference to various embodiments of the present invention, those skilled in the art will understand that various changes can be made in form and detail without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a first node in a wireless communication system, the method comprising: Receive a first message from a second node, where the first message includes at least one first single slice assistance information (S-NSSAI) associated with a protocol data unit (PDU) session and at least one second S-NSSAI to which the PDU session can be mapped; And When the first node does not support the at least one first S-NSSAI, or the resources associated with the at least one first S-NSSAI are unavailable or overloaded, the first node allocates resources for the PDU session based on the at least one second S-NSSAI.

2. The method according to claim 1, wherein, The first node is a destination base station, the second node is a source base station or an access control and mobility management function entity AMF, and the first message includes a handover request message.

3. The method according to claim 1 or 2, wherein, When the first node supports the first S-NSSAI, the first node selects the first S-NSSAI.

4. The method according to any one of claims 1 to 3, the method further comprising: Send a second message to the second node, where the second message includes the S-NSSAI determined based on the at least one second S-NSSAI.

5. The method according to claim 4, wherein, The second message includes a handover request confirmation message or a path handover request message.

6. The method according to claim 4, wherein, The first node is a base station, the second node is an AMF, and where the first message includes an initial context request message, and the second message includes an initial context response message.

7. The method according to claim 1, further comprising: Allocate resources for the PDU session based on the first message.

8. The method according to claim 7, wherein, The first message includes at least one of an initial UE context establishment request message received by the base station from a core network node, a PDU session resource establishment request message received by the base station from a core network node, a handover request message received by the destination base station from a core network node, a path handover request confirmation message received by the destination base station from a core network node, a handover request message received by the destination base station from a source base station, a handover requirement message received by the source core network node from a source base station, and a create UE context request message received by the destination core network node from the source core network node.

9. The method according to claim 7 or 8, wherein, Resources for the PDU session are also allocated based on QoS parameters of QoS flows in the PDU session, network slice resources supported by the base station serving the UE, and / or configurations of network operation and maintenance O&M for the PDU session.

10. The method according to claim 7 or 8, wherein, The first node is a base station or a core network node, and the second node is a core network node or a base station, where the core network node includes a session management function entity SMF or an access control and mobility management function entity AMF.

11. The method according to claim 7 or 8, wherein, The first message includes network slice policy information, and where the network slice policy information includes the at least one second S-NSSAI.

12. The method according to claim 11, wherein, The network slice policy information includes at least one second S-NSSAI with different priorities, and the first node gives priority to the resources corresponding to the second S-NSSAI with a higher priority when allocating resources.

13. The method according to claim 11, wherein, The network slice policy information is generated or updated by the AMF or the SMF.

14. The method according to claim 11, wherein, The network slice policy information is based on network slice policy information received from a user equipment UE.

15. The method according to any one of claims 11 to 14, wherein, The network slice policy information is generated or updated based on the network slice selection policy (NSSP), the subscription information of the UE, the quality of service (QoS) information of the service, and the S-NSSAI supported by the base station serving the UE.

16. The method according to claim 7 or 11, wherein, The S-NSSAI corresponding to the actually configured resources is sent to the core network node.

17. The method according to claim 16, wherein, The session management function (SMF) and / or the user plane function entity (UPF) for the PDU session of the UE is reselected according to the actually configured S-NSSAI.

18. The method according to claim 11 or 17, wherein when there are multiple SMFs that support the at least one S-NSSAI, the SMF among the multiple SMFs that supports the most second S-NSSAIs in the network slice policy information is selected.

19. The method according to claim 14, wherein If the SMF does not support at least one second S-NSSAI in the network slice policy information it receives, the network slice policy information is updated to ensure that the S-NSSAIs in the network slice policy information are all supported by the SMF.

20. The method according to claim 7 or 11, wherein When the method is used for handover, the S-NSSAI corresponding to the actually configured resources is included in the first message.

21. The method according to claim 7 or 20, wherein When the method is used for handover, if the first node supports the first S-NSSAI, it selects the resources corresponding to the first S-NSSAI for the PDU session and deletes the actually configured S-NSSAI in the PDU session context.

22. A method performed by a second node in a wireless communication system, the method comprising: Send a first message to the first node, the first message including at least one first single slice assistance information (S-NSSAI) associated with the protocol data unit (PDU) session and at least one second S-NSSAI to which the PDU session can be mapped; and Receive a second message from the first node, the second message including the S-NSSAI determined by the first node based on at least one second S-NSSAI when the first node does not support the at least one first S-NSSAI, or the resources associated with the at least one first S-NSSAI are unavailable or overloaded.

23. The method according to claim 22, wherein The first node is the target base station, the second node is the source base station or the access control and mobility management function entity (AMF), and wherein, the first message includes a handover request message, and the second message includes a handover request confirmation message.

24. The method according to claim 22 or 23, wherein The second node is the AMF, wherein the method further includes: Receive a third message from the session management function (SMF), the third message including the at least one second S-NSSAI.

25. The method according to any one of claims 22 to 24, wherein The second node is the AMF, and The method further includes: sending a handover command message to the source base station, wherein the handover command message includes the S-NSSAI determined based on at least one second S-NSSAI.

26. The method according to claim 22, wherein The first node is the base station, the second node is the AMF, and wherein, the first message includes an initial context request message, and the second message includes an initial context response message.

27. The method according to claim 22 or 23, wherein When the first S-NSSAI is supported by the first node, the first S-NSSAI is selected by the first node.

28. The method according to claim 22, wherein The second message includes a path switch request message.

29. The method according to claim 22, further comprising: Allocate resources for the PDU session based on the first message.

30. The method according to claim 29, wherein The first message includes at least one of an initial UE context establishment request message received by a base station from a core network node, a PDU session resource establishment request message received by the base station from the core network node, a handover request message received by a target base station from the core network node, a path switch request acknowledgment message received by the target base station from the core network node, a handover request message received by the target base station from a source base station, a handover requirement message received by a source core network node from the source base station, and a create UE context request message received by a target core network node from the source core network node.

31. The method according to claim 29 or 30, wherein Resources for a PDU session are also allocated for the PDU session based on QoS parameters of QoS flows in the PDU session, network slice resources supported by a base station serving the UE, and / or configurations of network operation and maintenance (O&M).

32. The method according to claim 29 or 30, wherein The first node is a base station or a core network node, and the second node is a core network node or a base station. Wherein, the core network node includes a session management function entity (SMF) or an access control and mobility management function entity (AMF).

33. The method according to claim 29 or 30, wherein The first message includes network slice policy information, and wherein, the network slice policy information includes the at least one second S-NSSAI.

34. The method according to claim 33, wherein, The network slice policy information includes at least one second S-NSSAI with different priorities, and the first node preferentially considers resources corresponding to the second S-NSSAI with a higher priority when allocating resources.

35. The method according to claim 33, wherein, The network slice policy information is generated or updated by the AMF or the SMF.

36. The method according to claim 33, wherein, The network slice policy information is based on network slice policy information received from a user equipment (UE).

37. The method according to any one of claims 33 to 36, wherein, The network slice policy information is generated or updated based on a network slice selection policy (NSSP), subscription information of the UE, quality of service (QoS) information of services, and S-NSSAIs supported by a base station serving the UE.

38. The method according to claim 29 or 33, wherein, The S-NSSAI corresponding to the actually configured resources is sent to the core network node.

39. The method according to claim 28, wherein, The SMF and / or user plane function entity (UPF) for the PDU session of the UE is reselected according to the actually configured S-NSSAI.

40. The method according to claim 33 or 39, wherein when there are multiple SMFs that support the at least one second S-NSSAI, the SMF among the multiple SMFs that supports the most second S-NSSAIs in the network slice policy information is selected.

41. The method according to claim 36, wherein, If the SMF does not support the at least one second S-NSSAI in the network slice policy information it receives, the network slice policy information is updated to ensure that the S-NSSAIs in the network slice policy information are all supported by the SMF.

42. The method according to claim 29 or 33, wherein, When the method is used for handover, the S-NSSAI corresponding to the actually configured resources is included in the first message.

43. The method according to claim 29 or 42, wherein, When the method is used for handover, if the first S-NSSAI is supported by the first node, resources corresponding to the first S-NSSAI are selected for the PDU session, and the actually configured S-NSSAI in the PDU session context is deleted.

44. A method performed by a user equipment UE in a wireless communication node, comprising: Receive a radio resource control (RRC) reconfiguration message from a first node, wherein the RRC reconfiguration message includes single slice assistance information (S-NSSAI) associated with a protocol data unit (PDU) session; and Send an RRC reconfiguration complete message to the first node. Wherein, the S-NSSAI is determined by a first node based on at least one second S-NSSAI included in a first message received from a second node when the first node does not support at least one first S-NSSAI, or resources related to the first S-NSSAI are unavailable or overloaded, and the first message further includes the at least one first S-NSSAI.

45. The method according to claim 44, wherein, The first node is a destination base station, the second node is a source base station or an access control and mobility management function entity AMF, and the first message includes a handover request message.

46. The method according to claim 44 or 45, wherein, When the first S-NSSAI is supported by the first node, the S-NSSAI includes the first S-NSSAI.

47. The method according to claim 46, wherein, The first node is a base station, the second node is an AMF, and Wherein, the first message includes an initial context request message, and the second message includes an initial context response message.

48. The method according to claim 44, wherein, Resources for a PDU session are based on the first message.

49. The method according to claim 48, wherein, The first message includes at least one of an initial UE context establishment request message received by the base station from a core network node, a PDU session resource establishment request message received by the base station from a core network node, a handover request message received by the destination base station from a core network node, a path switch request acknowledgment message received by the destination base station from a core network node, a handover request message received by the destination base station from a source base station, a handover requirement message received by the source core network node from the source base station, and a create UE context request message received by the destination core network node from the source core network node.

50. The method according to claim 48 or 49, wherein, Resources for a PDU session are also allocated based on QoS parameters of QoS flows in the PDU session, network slice resources supported by the base station serving the UE, and / or configurations of network operation and maintenance O&M for the PDU session.

51. The method according to claim 48 or 49, wherein, The first node is a base station or a core network node, and the second node is a core network node or a base station, Wherein, the core network node includes a session management function entity SMF or an access control and mobility management function entity AMF.

52. The method according to claim 48 or 49, wherein The first message includes network slice policy information, and Wherein, the network slice policy information includes the at least one second S-NSSAI.

53. The method according to claim 52, wherein The network slice policy information includes at least one second S-NSSAI with different priorities, and the first node gives priority to resources corresponding to the second S-NSSAI with a higher priority when allocating resources.

54. The method according to claim 52, wherein The network slice policy information is generated or updated by an AMF or an SMF.

55. The method according to claim 52, wherein The network slice policy information is based on network slice policy information received from a user equipment UE.

56. The method according to any one of claims 52 to 55, wherein The network slice policy information is generated or updated based on a network slice selection policy NSSP, subscription information of the UE, quality of service QoS information of services, and S-NSSAIs supported by the base station serving the UE.

57. The method according to claim 48 or 52, wherein The S-NSSAI corresponding to the actually configured resources is sent to the core network node.

58. The method according to claim 57, wherein The SMF and / or user plane function entity UPF for the PDU session of the UE is reselected according to the actually configured S-NSSAI.

59. The method according to claim 51 or 58, wherein when multiple SMFs support the at least one S-NSSAI, the SMF among the multiple SMFs that supports the most second S-NSSAI in the network slice policy information is selected.

60. The method according to claim 54, wherein If the SMF does not support at least one second S-NSSAI in the network slice policy information it receives, the network slice policy information is updated to ensure that the S-NSSAIs in the network slice policy information are all supported by the SMF.

61. The method according to claim 48 or 52, wherein When the method is used for handover, the S-NSSAI corresponding to the actually configured resources is included in the first message.

62. The method according to claim 48 or 61, wherein When the method is used for handover, if the first S-NSSAI is supported by the first node, the resources corresponding to the first S-NSSAI are selected for the PDU session, and the actually configured S-NSSAI in the PDU session context is deleted.

63. A first node in a wireless communication system, comprising: A transceiver configured to receive or transmit signals; And At least one processor coupled to the transceiver and configured to perform the method according to any one of claims 1 to 21.

64. A second node in a wireless communication system, comprising: A transceiver configured to receive or transmit signals; And At least one processor coupled to the transceiver and configured to perform the method according to any one of claims 22 to 43.

65. A UE in a wireless communication system, comprising: A transceiver configured to receive or transmit signals; And At least one processor coupled to the transceiver and configured to perform the method according to any one of claims 44 to 62.

66. A base station in a wireless communication system, comprising: A transceiver configured to receive or transmit signals; And At least one processor coupled to the transceiver and configured to perform the method according to any one of claims 1 to 43.

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