CN109996303B

CN109996303B - System switching method and communication entity

Info

Publication number: CN109996303B
Application number: CN201711487978.5A
Authority: CN
Inventors: 孙海洋; 吴义壮; 熊春山
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-12-29
Filing date: 2017-12-29
Publication date: 2021-06-01
Anticipated expiration: 2037-12-29
Also published as: CN109996303A; WO2019129115A1

Abstract

The application provides a system switching method and a communication entity, comprising the following steps: PCF receives capability information of the terminal device; the PCF sends a request message to the NWDAF according to the capability information of the terminal device, wherein the request message is used for requesting EPC information; the EPC information is information of an EPC which the terminal device can access; the PCF receives the EPC information sent by the NWDAF; and the PCF determines whether to release the PDU session or not according to at least the EPC information. The PCF obtains the possibility that the UE moves to each EPC in advance, and after the UE moves to a specific position, the PCF can judge whether PDU conversation of the UE needs to be released or not according to the obtained possibility that the UE moves to the EPC, so that synchronization of PDU conversation states of the UE and the EPC is ensured, TAU cannot fail to be executed when the UE moves to the EPC, air interface signaling is saved, and air interface delay is reduced.

Description

System switching method and communication entity

Technical Field

The present application relates to the field of wireless communication technologies, and in particular, to a method for system handover in a wireless communication system and a communication entity.

Background

Interworking of 5G networks with 4G networks in the existing 3GPP (3rd Generation Partnership Project) standard, there are two modes of interworking: single-registration mode and dual-registration mode. In the registration mode, when a UE (user equipment) supports a single registration mode and a network supports interworking with an N26 interface, for idle-state mobility from 5GC (5th generation core network) to EPC (evolved Packet core network), the UE performs a TAU (tracking area update) procedure of 4G-GUTI mapped from 5G-GUTI (global unique temporary identity), and if the UE has an established Packet Data Unit (PDU) session or if the UE or the UE supports "connectionless attachment", the MME acquires MM (mobility management) and SM (session management) contexts of the UE. If the UE has no PDU session registration in the 5GC, and the UE or EPC does not support "connectionless attach", the UE performs an attach procedure. For a connected state move from 5GC to EPC, an intersystem handover is performed. For idle movement from the EPC to the 5GC, the UE performs a registration procedure of the 5G-GUTI mapped from the 4G-GUTI, and an Access and Mobility Management function (AMF) entity and a Session Management Function (SMF) entity acquire MM and SM contexts of the UE from the EPC. For a connected state move from the EPC to the 5GC, an intersystem handover is performed.

That is, in the single registration mode, when the UE in an idle state moves from the 5GC to the EPC, the UE and the EPC both support connectionless attachment, and the UE performs TAU; when at least one of the UE and the EPC does not support connectionless attachment, the UE executes TAU operation when perceiving that the UE has the established PDU session; otherwise, an attach operation is performed. In 5G, when the UE is allowed to be in idle state, the core network implicitly deactivates the PDU session, so that the PDU session state of the UE and the PDU session state of the core network may not be synchronized, that is, the UE perceives that it has a PDU session, but the network side considers that there is no PDU session. The idle UE moves from 5GC to EPC, and initiates TAU procedure if it senses that it has PDU session. When the UE or EPC does not support connectionless attachment, the network side detects that the UE does not establish a PDU session, the TAU of the UE will be rejected, and the UE will re-initiate an attachment procedure. Such a trial and error approach increases the time delay and signaling of the air interface.

Disclosure of Invention

The application provides a system switching method, which is used for ensuring PDU session state synchronization of UE and EPC when the UE is switched from a 5G network to the EPC network, and executing TAU when the UE moves to the EPC network can not fail.

In a first aspect, an embodiment of the present application provides a method for analyzing a system handover, where the method receives capability information of a terminal device for a first communication entity; the first communication entity sends a request message to a second communication entity according to the capability information of the terminal device, wherein the request message is used for requesting EPC information; the EPC information is information of an EPC which the terminal device can access; the first communication entity receives the EPC information sent by the second communication entity; the first communication entity determines whether to release the PDU session based on at least the EPC information. The first communication entity obtains the possibility that the UE moves to each EPC in advance, and after the UE moves to a specific position, the first communication entity can judge whether the PDU session of the UE needs to be released or not according to the obtained possibility that the UE moves to the EPC, so that the PDU session state synchronization of the UE and the EPC is ensured, and the execution of the TAU does not fail when the UE moves to the EPC, so that air interface signaling is saved, and air interface delay is reduced.

In one possible design, a first communication entity generates policy information at least according to the EPC information, and sends the policy information to a third communication entity, and the first communication entity receives the PDU session of the terminal device reported by the third communication entity when the policy information is satisfied.

In another possible design, the first communication entity updates the policy information according to information reported by the fourth communication entity.

In another possible design, the first communication entity determines whether to release the PDU session based on at least one of the EPC information and status information.

In another possible design, the first communication entity sends a rejection message to the third communication entity when the first communication entity determines not to release the PDU session.

In another possible design, the first communication entity determines to release the PDU session, and pages the ue when the ue is in idle state.

In a second aspect, an embodiment of the present application provides a communication entity, which may execute any one of the methods provided in the foregoing first aspect.

In a possible design, the communication entity has a function of implementing the behavior of the first communication entity in any of the methods in the first aspect, and the function may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described functions. Optionally, the communication entity may be an AMF entity, an MME, a session management entity, a policy control entity, or a UE.

In one possible design, the structure of the communication entity includes a processor and a transceiver, and the processor is configured to support the communication entity to perform corresponding functions in any of the methods of the first aspect, such as generating, receiving or processing data and/or information involved in the methods. The transceiver is configured to support communication between the communication entity and other entities, and to send or receive information or instructions related to any of the methods of the first aspect to or from other entities. The communication entity may also include a memory for coupling with the processor that retains program instructions and data necessary for the communication entity.

In a third aspect, a further system handover method is provided in an embodiment of the present application, including a communication network entity receiving mobility information of a user equipment, where the mobility information is information that the user equipment moves among multiple EPCs; the network entity determines a likelihood that the user equipment is likely to move each EPC based on the mobility information. The NWDAF carries out statistic analysis on the mobile information to obtain the probability, so that the processing resource of the PCF can be saved, and the accuracy of PCF judgment is improved.

In a fourth aspect, an embodiment of the present application provides a communication entity, which is capable of implementing any one of the parameter determination methods provided in the third aspect.

In a fifth aspect, an embodiment of the present application provides a computer storage medium for storing computer software instructions for a communication entity provided in the second aspect, which includes a program designed to execute the first aspect.

In a sixth aspect, the present application provides a computer storage medium for storing computer software instructions for a communication entity provided in the fourth aspect, which contains a program designed to execute the third aspect.

In a seventh aspect, the present application also provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of the first aspect described above, the computer program product comprising computer executable instructions, the computer executable instructions being stored on a computer readable storage medium. The processor of the communication entity may read the computer executable instructions from the computer readable storage medium; the processor executes the computer-executable instructions to enable the communication entity to execute the steps executed by the communication entity in the method provided by the embodiment of the application, or to enable the communication entity to deploy the functional unit corresponding to the steps.

In an eighth aspect, the present application also provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of the third aspect described above, the computer program product comprising computer executable instructions, the computer executable instructions being stored on a computer readable storage medium. The processor of the communication entity may read the computer executable instructions from the computer readable storage medium; the processor executes the computer-executable instructions to enable the communication entity to execute the steps executed by the communication entity in the method provided by the embodiment of the application, or to enable the communication entity to deploy the functional unit corresponding to the steps.

In a ninth aspect, the present application further provides a chip system comprising a processor for enabling a communication entity to implement the functions referred to in the above aspects, e.g. to generate, receive or process data and/or information referred to in the above methods. In one possible design, the system-on-chip further includes a memory for storing program instructions and data necessary for the terminal device. The chip system may be constituted by a chip, or may include a chip and other discrete devices.

Drawings

Embodiments of the present application will be described in more detail below with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a possible application scenario provided in the present application;

FIG. 2 is a schematic illustration of a possible application environment for yet another embodiment of the present application;

FIG. 3 is a schematic illustration of a possible application environment for yet another embodiment of the present application;

FIG. 4 is a schematic illustration of a possible application environment for yet another embodiment of the present application;

FIG. 5 is a flow chart of a method provided by an embodiment of the present application;

FIG. 6 is an interaction diagram of a communication method according to another embodiment of the present application;

FIG. 7 is an interaction diagram of a communication method according to another embodiment of the present application;

FIG. 8 is an interaction diagram of a communication method according to an embodiment of the present application;

FIG. 9 is an interaction diagram of a communication method according to another embodiment of the present application;

FIG. 10 is an interaction diagram of a communication method according to an embodiment of the present application;

FIG. 11 is an interaction diagram of a communication method according to another embodiment of the present application;

FIG. 12 is a schematic view of the apparatus provided herein;

FIG. 13 is a schematic view of another apparatus provided herein;

fig. 14 is a schematic diagram of a communication entity provided in the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

The network architecture and the service scenario described in the embodiment of the present application are for more clearly illustrating the technical solution of the embodiment of the present application, and do not limit the technical solution provided in the embodiment of the present application, and as a person having ordinary skill in the art knows that along with the evolution of the network architecture and the appearance of a new service scenario, the technical solution provided in the embodiment of the present application is also applicable to similar technical problems.

A terminal device in the embodiments of the present application may refer to a user equipment, an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user device. The terminal device may also be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with Wireless communication function, a computing device or other processing device connected to a Wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G Network or a terminal device in a future evolved Public Land Mobile Network (PLMN), and the like, which are not limited in this embodiment.

The Base Station in this embodiment may be a device for communicating with a terminal device, and the Base Station may be a Base Transceiver Station (BTS) in a Global System for Mobile communications (GSM) System or a Code Division Multiple Access (CDMA) System, may also be a Base Station (NodeB, NB) in a Wideband Code Division Multiple Access (WCDMA) System, may also be an evolved Base Station (eNB, eNodeB) in an LTE System, may also be a wireless controller in a Cloud Radio Access Network (CRAN) scenario, and the like, and the present embodiment is not limited.

The network element in the embodiment of the present application may include a network device in a 5G system architecture and/or a 4G system architecture. Wherein the 4G system architecture may comprise an EPS system architecture. For example, a Network element may include an Access and Mobility Management Function (AMF) Entity, a Mobility Management Entity (MME), a Session Management Function (SMF) Entity, a Unified Data Management (UDM), a Policy Control Function (PCF) Entity, a Policy and Charging Rule Function (PCRF) Entity, a Packet Data Network (PDN), a Packet Data Unit (PDU), a Control plane Gateway (PDN Gateway-Control plane, PGW-C), a User plane Gateway (PDN Gateway-User plane, PGW-U), a home Subscriber Server (home Subscriber Server, HSS), an Application Function Entity (HSS), an Application Function (AF), and the like.

The network architecture and the service scenario described in this application are for more clearly illustrating the technical solution of this application, and do not constitute a limitation to the technical solution provided in this application, and it can be known by those skilled in the art that the technical solution provided in this application is also applicable to similar technical problems along with the evolution of the network architecture and the appearance of new service scenarios.

As shown in fig. 1, the schematic view is a possible application scenario of the present application, and includes at least one terminal device 10, which communicates with a Radio Access Network (RAN) through a wireless interface, where the RAN includes at least one base station 20, and for clarity, only one base station and one terminal device are shown in the drawing. The terminal Device 10 may also communicate with another terminal Device 10, such as in a Device-to-Device (D2D) or Machine-to-Machine (M2M) scenario. The base station 20 may communicate with the terminal device 10, and may also communicate with another base station 20, such as a macro base station and an access point. The RAN is connected to a Core Network (CN). Alternatively, the CN may be coupled to one or more Data Networks (DN), such as the Internet, a Public Switched Telephone Network (PSTN), or the like.

In this application, the terms "network" and "system" are often used interchangeably, but those skilled in the art will understand the meaning.

Some of the terms referred to in this application are described below for the sake of clarity.

1) And Terminal Equipment (Terminal Equipment), also known as user Equipment (english: user Equipment, abbreviation: UE), or Terminal (Terminal), is a device that provides voice and/or data connectivity to a user, such as handheld devices, in-vehicle devices, wearable devices, computing devices, control devices, or other processing devices connected to wireless modems, with wireless connection or communication capabilities, and various forms of mobile stations (english: mobile station, abbreviation: MS), etc. Common terminal devices include: the mobile phone (phone), the tablet computer (pad), the notebook computer (notebook), the palm computer, the mobile internet device (MID for short), the wearable device such as a smart watch, a smart bracelet, a pedometer, etc. For convenience of description, the above-mentioned devices are collectively referred to as terminal devices in this application.

2) The access network entity is divided into a 5G access network entity and a 4G access network entity, and is a device for accessing a terminal device to a wireless network, including but not limited to: evolved Node B (eNB), Radio Network Controller (RNC), Node B (NB), Base Station Controller (BSC), Base Transceiver Station (BTS), Home Base Station (e.g., Home evolved Node B (HNB)), Base Band Unit (BBU), Base Station (gNB), transmission Point (Transmit and receive Point (TRP), Transmission Point (TP), mobile switching center (Wifi), Access Point (AP), etc., and may include macro Base Station, micro Base Station, relay Point (AP), etc., or may include Base Station (eNB), Base Transceiver Station (BTS), Base Transceiver Station (BBU), Base Station (G NodeB), transmission Point (AP), etc., and may also include Access Point (Access Point, AP), etc., in various forms, An access point or a Radio Remote Unit (RRU for short), etc. The names of devices with base station functions may vary in different systems, such as an evolved node B (eNB or eNodeB) in an LTE network, a node B (node B) in the 3rd Generation (3G) network, and so on.

3) And MME: the MME is a key control node of a 3GPP protocol Long Term Evolution (English: LTE for short) access network, is responsible for the positioning of idle UE and the paging process including relaying, and is simply responsible for the control plane signaling processing part. It involves the bearer activation/modification/deletion procedure and selects an SGW entity for a UE when it initializes and connects.

4) And AMF entity: the AMF is responsible for Access and mobility Management, is a termination point of an NG2 interface, terminates a Non-Access Stratum (NAS) message, completes registration Management, connection Management, reachability Management, mobility Management, and the like, and transparently routes a Session Management message to a Session Management Function (SMF) entity.

5) And SGW entity: the SGW is an important network element in an Evolved Packet Core (EPC), and the function and function of the SGW are equivalent to the user plane of a Serving GPRS Support Node (SGSN) network element in the original 3G core. And the SGW entity can be divided into a control plane SGW-C entity and a user plane SGW-U entity, the SGW-C entity is provided with an interface with the PGW-C entity and the SGW-U entity, and the SGW-U entity is provided with an interface with the PGW-U entity.

6) And PGW entity: the PGW network element entity introduced in the EPC system is similar to the function of a GPRS Support Node (GGSN), provides functions of session management and bearer control, data forwarding, IP address allocation, non-3 GPP user access and the like for a border Gateway of the EPC system, is an anchor point of a public data network PDN accessed by 3GPP and non-3 GPP, and can be divided into a control plane PGW-C entity and a user plane PGW-U entity.

7) An SMF entity: responsible for session management, IP address allocation and management of the UE, allocation and selection of anchor point functions, and (re) selection of UPF and user plane paths, etc.

8) And the PCF entity: the main function is a policy decision point, provides rules based on service data flow and application detection, gating, QoS and flow-based charging control, and is a policy control function entity in the 5G system.

9): policy and Charging Rules Function (PCRF for short): the policy and charging control policy decision point is a policy and charging control policy decision point of service data flow and IP bearing resources, and selects and provides available policy and charging control decisions for a policy and charging execution function entity, and the PCRF entity is a 4G policy and charging control function unit.

10) User plane functions (english: user Plane Function, UPF for short) entity: the method is used for user plane functions such as data packet routing and transmission, user plane QoS processing, uplink service verification, packet identification of a transmission layer, downlink data packet caching, downlink data packet indication, legal monitoring and the like.

11) User data management (english: the Unified Data manager, for short: UDM) entity: and the system is responsible for handling trust, location management and subscription management. Providing access to a user data storage unit, supporting access authentication, registration, mobility management, etc.

12) And a home subscriber server (english: home Subscriber Server, abbreviated as: HSS) entity: the server is used for storing the user subscription information in the EPS and is mainly responsible for managing the subscription data of the user and the position information of the mobile user.

In the following, some general concepts or definitions referred to in the embodiments of the present application are explained, it should be noted that some english words in this document are simply referred to as descriptions of the embodiments of the present application taking the LTE system as an example, which may change with the evolution of the network, and specific evolution may refer to descriptions in corresponding standards.

In this application, the 4G network may also be referred to as an EPS network, an access network of the 4G network is referred to as E-UTRAN, and a core network of the 4G network is referred to as EPC network. The 5G network can also be called a New Radio (NR) network, and the 5G system is called 5GS for short. In this application, a plurality of terms having the same meaning will be used interchangeably.

The "data" in this application refers to traffic data in general, but may also include content such as signaling and messages that the system needs to transmit, for example, a reference signal, uplink and downlink control messages, and the like.

The term "and/or" in this application is only one kind of association relationship describing the associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

In the embodiment of the present application, the context in which the user equipment switches between the EPS system and the 5G system is described as an example.

The following describes an application environment of the embodiment of the present application with reference to fig. 2 and 3. Fig. 2 and 3 are schematic diagrams of possible system architectures of embodiments of the present application, respectively. Fig. 2 shows an interworking architecture between a 5G system and an EPS system in a non-roaming scenario. Fig. 3 shows an interworking architecture of a 5G system and an EPS system in a local breakout (local breakout) roaming scenario.

In the architectures shown in fig. 2 and 3, in order to support interworking of the 5G system and the EPS system, a first interface is introduced. The first interface refers to a communication interface between a mobility management entity of the 5G system and a mobility management entity of the EPS system. The mobility management entity of the 5G system may be an AMF, and the mobility management entity of the EPS system may be an MME. In the embodiment of the present application, the first interface may be represented by an N26 interface. In the case where the system architecture supports the N26 interface, the interworking architecture can support handover between the 5G and EPS systems. It should be noted that, in the interworking architecture, the support of the N26 interface is optional, and the service continuity can be guaranteed only in the interworking network supporting the N26 interface by using the handover procedure.

Specifically, in the architectures shown in fig. 2 and 3, a network element in the EPS system and a network element in the 5G system may be included. Some modules in the architecture include the functionality of network elements in the EPS system and network elements in the 5G system. For example, HSS + UDM module, PCF + PDRF module, SMF + PGW-C module, UPF + PGW-U module, the modules and communication interfaces involved in the architecture 100-300 are described below.

UPF + PGW-U Module: the module can be used for the data transmission of EPS and can also provide the data transmission function of 5G in the intercommunication architecture.

SMF + PGW-C module: the module is used for session establishment, deletion and modification management, and in an intercommunication framework, the module can provide the session management function of EPS and the session management function of 5G.

PCF + PCRF module: the module is used for a policy and charging control entity, and in an intercommunication framework, the module can provide both the policy and charging control of EPS for UE and the policy and charging control of 5G.

HSS + UDM Module: the module is used for storing the subscription data of the user, and in the interworking architecture, the module not only stores the subscription information of the EPS of the UE, but also stores the subscription information of the 5G of the UE.

5G Radio Access Network (RAN): and providing a wireless air interface for the UE to access the core network, thereby acquiring the corresponding service.

The application function is as follows: the Application Function (AF) interacts with the core network to provide services or services, supports the access capability opening Function, interacts with the strategy architecture, provides Application information, and the like.

Evolved universal terrestrial radio access network (E-UTRAN): the method is used for wireless resource management, and air interface resources are established, modified or deleted for the UE. Provide for transmission of data and signaling for the UE, and the like.

An AMF module: the method is used for access and mobility management of users, and mainly comprises registration management, reachability management and mobility management of the users, paging management, access authentication, encryption and integrity protection of authorized non-access layer signaling and the like.

An MME module: for mobility management of the user. For example, the method mainly comprises the attachment management, the reachability management, the mobility management, the paging management, the access authentication, the encryption and integrity protection of the authorized non-access layer signaling and the like of the user.

SGW module, user plane gateway, and user plane termination point of E-UTRAN. As a local mobility anchor for handovers between base stations. Managing the routing and transmission of data packets, adding packet labels at the transport layer, etc.

S1-MME interface: control plane interface between MME and E-UTRAN.

S1-U interface: user plane interface between S-GW and E-UTRAN.

S5-U interface: and the user plane interface between the SGW and the PGW-U is used for transmitting user plane data of the UE.

S5-C interface: and the control plane management interface between the SGW and the PGW-U is used for establishing user plane connection between the SGW and the PGW-U for the UE.

S6a interface: and the interface between the MME and the HSS is used for acquiring the subscription data of the user and executing authentication and authorization functions for the UE.

Interface S11: and the interface between the SGW and the MME is used for establishing the bearer of the user plane.

N1 interface: interface between UE and AMF, signaling management and transmission of user non-access stratum.

N2 interface: (R) AN interface between the AN and the AMF for transmission of signaling.

N3 interface: the UPF and (R) AN are direct interfaces for transmitting user data.

N4 interface: and the interface between the SMF and the UPF is used for establishing a transmission channel of a user plane.

N7 interface: and the interface between the SMF and the PCF is used for formulating and transmitting the policy control and the charging information.

N8 interface: and the interface between the AMF and the UDM is used for acquiring the mobile related subscription information of the user and the like.

N10 interface: and the interface between the SMF and the UDM is used for acquiring the session management related subscription information of the user and the like.

N11 interface: and an interface between the SMF and the AMF is used for transmitting session management information and the like.

N15 interface: and the interface between the AMF and the PCF is used for acquiring access and mobility-related policy information.

In the architecture 300 shown in FIG. 3:

the v-PCF + v-PCRF represents a policy control body supporting intercommunication in a roaming network or a visiting network, and not only supports the functions of providing 4G policy and charging control and the like, but also supports the functions of providing 5G policy and charging control and the like.

v-SMF denotes SMF in a roaming network.

The v-PCF represents a PCF in a roaming network.

In addition, the HPLMN in fig. 3 represents a home network, and the VPLMN represents a visited network or a roaming network. For example, HPLMN denotes (home) public land mobile network (HPLMN), VPLMN denotes visited (visit) or roaming PLMN. N24 is a reference point or interface between the HPLMN and the VPLMN.

It should be understood that the above description of the functions of each module is only an example, and each module may also have other functions, and the embodiments of the present invention are not limited thereto.

Fig. 4 is a 5G policy control architecture, where a network architecture related to policy control includes a network data analysis Function (NWDAF) network element, the NWDAF may analyze big data and may send analysis information obtained based on the analysis to a policy control network element (PCF) in the network architecture, and the PCF may generate a policy based on the analysis information sent by the NWDAF and may send the generated policy to a policy control execution network element, for example, an Access and Mobility Management Function (AMF) or a Session Management Function (SMF) in the network architecture, and the policy control execution network element may control the policy to be executed.

The solutions provided by the embodiments of the present application will be described in more detail below with reference to the accompanying drawings.

Referring to fig. 5, a flowchart of a method for determining parameters provided in the present application is applied to UE switching from a 5GS network to an EPS network, and includes the following steps:

step 501, a first communication entity receives capability information of a terminal device;

step 502, the first communication entity sends a request message to a second communication entity according to the capability information of the terminal device, wherein the request message is used for requesting EPC information; the EPC information is information of an EPC which the terminal device can access;

step 503, the first communication entity receives the EPC information sent by the second communication entity;

step 504, the first communication entity determines whether to release the PDU session based at least on the EPC information.

In the embodiment shown in fig. 5, the first communication entity obtains in advance the possibility that the UE moves to each EPC, and after the UE moves to a specific location, the first communication entity may determine whether to release the PDU session of the UE according to the obtained possibility that the UE moves to the EPC, so as to ensure that the PDU session states of the UE and the EPC are synchronized, and when the UE moves to the EPC, execution of the TAU does not fail, thereby saving an air interface signaling and reducing an air interface delay.

Referring to fig. 6, for an embodiment provided by the present application, another embodiment shown in fig. 7 and fig. 8 is provided, where fig. 7 shows a related flow after initial registration of a UE, and fig. 8 shows a related flow after a PDU session establishment procedure. In the embodiments shown in fig. 6 to 8, the first communication entity is PCF, the second communication entity is NWDAF, and the third communication entity is IWK (interworking) SMF. Further, in the embodiment shown in fig. 5, the fourth communication entity is an AMF. The following is a specific process of the embodiment shown in fig. 6 to 9, including:

step 1, the UE reports the capability of the UE, namely UE capability information. Optionally, the UE may perform capability reporting when the PDU session is established, or may perform capability reporting when the PDU session is registered, and the manner shown in fig. 6 is exemplified by performing capability reporting when the PDU session is established. In the embodiments shown in fig. 7 and fig. 9, the capability reporting is performed during registration, and in the PUD session establishment process, the IWK SMF requests policy information from the PCF;

the UE may send the capability information alone, or may carry the capability information in other messages, and in the embodiment shown in fig. 6, the capability information of the UE may be included in the session establishment request message, where the capability information is used to indicate whether the UE supports connectionless attachment. And the IWK SMF reports the UE capability information to the PCF, and optionally, the IWK SMF sends the UE capability information to the PCF by including the UE capability information in the policy request message. In the embodiment shown in fig. 7, the registration message includes UE capability information and reports the UE capability information to the AMF, and the AMF reports the UE capability information to the PCF through the UE context setup/modification message. IWK SMF is SMF + PGW-C module, IWK SMF can be SMF supporting 4G and 5G system intercommunication.

The UE capability information includes at least information indicating whether the UE supports connectionless attachment.

In the embodiment shown in fig. 6, optionally, the PDU session is an IWK PDU session, and the UE reports its capability when establishing an IWK DNN (data network name) session. The IWK PDU session is established for the UE, and supports both IWK and DNN of an EPS system and a 5G system. The UE has the capability to determine whether the session is an IWK PDU session.

And 2, the PCF subscribes different services to the NWDAF according to the capability information of the UE, and the service subscribed to the NWDAF can point to the NWDAF request information.

When the capability information of the UE indicates that the UE does not support the UE without connection attachment, the PCF requests the NWDAF to initiate the position information of the TAU when the UE moves to all EPCs;

when the capability information of the UE indicates that the UE supports the UE without connection attachment, the PCF requests the NWDAF to request the UE to move to the EPC without connection attachment and initiates the position information of the TAU.

The PCF may also initiate location information for the TAU when requesting all EPCs to which the UE will move, without regard to the capability information of the UE. Compared with the scheme, when the UE requests different position information according to the capability information, the signaling resource is further saved, and the analysis efficiency of the requested position information is improved.

The request message sent by the PCF to the NWDAF may include UE parameter information, such as UE identification information; IWK error information may also be included. Wherein the IWK error information is used to indicate that the PCF or AMF requests from the NWDAF to indicate that an error occurs during interworking.

In addition, the PCF subscribes to different services from the NWDAF, the subscribed information may be mobility information of the UE, for example, location information of initiating a TAU when the UE will move to all EPCs, or location information of initiating a TAU when the UE will move to a location that does not support a connectionless attached EPC, and optionally, the location information may be indicated by an AMF ID; the subscribed information may also be probability statistic analysis information made by the NWDAF according to the UE movement information, or an AMF ID corresponding to at least one piece of location information to which the UE is most likely to move. The PCF subscribes to a different service from the NWDAF, i.e., the EPC information requested by the PCF from the NWDAF may be at least one of mobility information or probabilistic analysis information.

And 3, the NWDAF sends the information requested by the UE to the PCF.

The NWDAF collects mobility information of the UE, where the mobility information may be a cell identity where the UE is located, or an AMF ID, or geographic location information from a third-party application, mobility pattern (mobility pattern), and the like, and the mobility information may include one or more of the above. Wherein the AMF ID may be an AMF ID corresponding to at least one location information to which the UE is most likely to move. Mobility mode is a concept used by the AMF to characterize and optimize UE mobility. The AMF determines and updates a mobility pattern of the UE based on subscription of the UE, UE mobility statistics, network local policy and UE assistance information, or any combination thereof. The statistics of UE mobility may be historical or expected UE movement trajectories. The AMF may use the UE mobility patterns to optimize mobility support provided to the UE, e.g., registration area allocation. All the collected mobile information forms big data, and the NWDAF can perform statistics according to the big data to obtain the mobile rule of each UE, so as to obtain the probability that the UE moves to one or more EPCs to initiate a TAU. Further, the UE may also perform statistics, and may perform statistics on the probability that each UE moves to a specific EPC to initiate TAU when moving to a specific EPC at a specific time period and/or a specific location. The NWDAF carries out statistical analysis on the big data to obtain the probability, so that the processing resources of the PCF can be saved, and the accuracy of PCF judgment is improved.

Optionally, the message sent by the MWDAF may further include IWK error information. Wherein the IWK error information is used to indicate that the PCF or AMF requests from the NWDAF to indicate that an error occurs during interworking.

And 4, the PCF generates the strategy information and sends the strategy information to the IWK SMF. The strategy information is used for indicating IWK SMF, reporting PDU conversation to PCF under the condition of meeting the strategy information, and PCF deciding whether to release the PDU conversation. The policy indicated by the policy information may be that when the UE arrives at a specific area, the IWK SMF reports the IWK PDU session. The policy information may be a trigger, and when the trigger condition is satisfied, the IWK SMF reports the PDU session. Alternatively, as shown in fig. 9, the PCF may receive the policy request information sent by the IWK SMF first, and then send the policy information.

And 5, under the condition that the IWK SMF meets the strategy indicated by the strategy information, if the IWK SMF judges that the PDU session of the IWK DNN needs to be released, the IWK SMF reports to the PCF and requests the PCF to judge whether the PDU session needs to be released or not. This PDU session may be the last PDU session of the IWK DNN. Wherein IWK DNN is DNN supporting 4G and 5G systems simultaneously.

In addition, after step 4, the PCF may also update the policy information and send the new policy information to the IWK SMF, which determines whether reporting is needed according to the new policy information.

Optionally, the PCF may receive information reported by the AMF to update the policy information, where the information reported by the AMF includes at least one of the information of the location, the time, and the like of the UE;

optionally, the IWK SMF sends a policy control request message to the PCF, where the policy control request message may include the SMF ID of the IWK SMF. And the PCF judges that the SMF is the IWK SMF according to the SMF ID and immediately issues the strategy.

And 6, if the PCF judges that the PDU session is not released according to the information acquired from the NWDAF and further by referring to state information, such as the time state or the position state of the UE, and the like, the IWK SMF is rejected by sending a message. Otherwise, the release of the PDU session is allowed.

The PCF refuses the release of the PDU session, and can inform the IWK SMF to refuse the release of the PDU session in a message sending mode.

Fig. 9 is a flowchart of another embodiment of the present application, where fig. 9 shows an embodiment where the first communication entity is a PCF, the second communication entity is an NWDAF, and the third communication entity is an AMF. The flow of the embodiment shown in fig. 9 includes:

step 1, reporting the capability of the UE, as exemplified in fig. 9 by performing capability reporting when the UE performs capability reporting PDU session establishment during registration; in another optional embodiment, the UE performs capability reporting when the PDU session is established.

The UE may send the capability information separately, or may carry the capability information in other messages.

Optionally, the PDU session is an IWK PDU session, and the UE reports its own capability when establishing an IWK DNN session. The IWK PDU session is established for the UE, and supports both IWK and DNN of an EPS system and a 5G system. The UE has the capability to determine whether the session is an IWK PDU session.

Step 2, the PCF subscribes to different services to the NWDAF according to the capability information of the UE, and the service subscription to the NWDAF may be to request information from the NWDAF, including:

In addition, the PCF subscribes to different services from the NWDAF, the subscribed information may be mobility information of the UE, for example, location information of initiating a TAU when the UE will move to all EPCs, or location information of initiating a TAU when the UE will move to a location that does not support a connectionless attached EPC, and optionally, the location information may be indicated by an AMF ID; the AMF ID may be an AMF ID corresponding to at least one location information to which the UE is most likely to move. The subscribed information may also be probability statistics analysis information made by the NWDAF based on the UE movement information. The PCF subscribes to a different service from the NWDAF, i.e., the EPC information requested by the PCF from the NWDAF may be at least one of mobility information or probabilistic analysis information.

And 3, the NWDAF sends the information requested by the PCF to the PCF.

The NWDAF collects mobility information of the UE, where the mobility information may be an identity of a cell where the UE is located, or an AMF ID, geographical location information from a third-party application, mobility pattern (mobility pattern), and the like, and the mobility information may include one or more of the above. Wherein the AMF ID may be an AMF ID corresponding to at least one location information to which the UE is most likely to move. Mobility mode is a concept used by the AMF to characterize and optimize UE mobility. The AMF determines and updates a mobility pattern of the UE based on subscription of the UE, UE mobility statistics, network local policy and UE assistance information, or any combination thereof. The statistics of UE mobility may be historical or expected UE movement trajectories. The AMF may use the UE mobility patterns to optimize mobility support provided to the UE, e.g., registration area allocation. All the collected mobile information forms big data, and the NWDAF can perform statistics according to the big data to obtain the mobile rule of each UE, so as to obtain the probability that the UE moves to one or more EPCs to initiate a TAU. Further, the UE may also perform statistics, and may perform statistics on the probability that each UE moves to a specific EPC to initiate TAU when moving to a specific EPC at a specific time period and/or a specific location. The NWDAF carries out statistical analysis on the big data to obtain the probability, so that the processing resources of the PCF can be saved, and the accuracy of PCF judgment is improved.

And 4, when the UE moves to the AMF corresponding to the AMF ID sent by the NWDAF, the PCF sends down a paging trigger, wherein the paging trigger contains UE position information, and when the position information is used for indicating the position of the UE identified by the position information, if the AMF judges that the PDU session is released and the UE is in an idle state, the trigger is triggered.

And 5, after the UE is in the designated position and in the idle state, the AMF determines that the last PDU session is released, and pages the UE. Wherein the specified position is a position indicated by position information contained in the trigger.

And step 6, the AMF pages the UE, the UE receives the paging to enable the session state of the UE and the EPC to be synchronous, and the UE executes an attach (attach) process when moving to the EPC. By the embodiment, the UE directly performs the attachment execution when moving to the EPC, thereby reducing the time delay of an air interface.

Alternatively, based on the embodiment shown in fig. 9, the embodiment shown in fig. 10 is a scenario in which the UE switches or registers to a new AMF. In the case that the PCF receives the information sent by the NWDAF in step 3 shown in fig. 9, the UE accesses a new AMF through the existing registration or handover procedure, the new AMF sends a UE context setup request or a UE context modification request message to the PCF, the PCF sends a paging trigger to the new AMF accessed by the UE, and when the UE is in an idle state at a designated location, the AMF pages the UE after determining that the last PDU session is released. Wherein the specified position is a position indicated by position information contained in the trigger. The AMF performs paging on the UE, the UE receives the paging to synchronize the session states of the UE and the EPC, and the UE performs an attachment process when moving to the EPC. By the embodiment, the UE directly performs the attachment execution when moving to the EPC, thereby reducing the time delay of an air interface.

Fig. 11 shows another embodiment of the present application, in which the first communication entity is an AMF and the second communication entity is an NWDAF, and the flow of the embodiment shown in fig. 11 includes:

step 1, UE reports own capability. The UE can carry out capability reporting when the PDU session is established during registration; in another optional implementation, the UE may also report the capability information to the new AMF each time the UE performs a handover procedure and accesses through a different AMF.

Optionally, the PDU session is an IWK PDU session, and the UE reports its own capability when establishing an IWK DNN session. The IWK PDU session is a session which is established by UE and supports IWK (interworking), and the type of session is a session which simultaneously supports APN of an EPS system and DNN of a 5G system. The UE has the capability to determine whether the session is an IWK PDU session.

Step 2, the AMF subscribes to different services to the NWDAF according to the capability information of the UE, and the service subscription to the NWDAF may be to request information from the NWDAF, including:

The request message sent by the AMF to the NWDAF may further include UE parameter information, such as at least one of UE identification information and IWK error information. Wherein the IWK error information is used to indicate that the PCF or AMF requests from the NWDAF to indicate that an error occurs during interworking.

In addition, the AMF subscribes to different services to the NWDAF, the subscribed content may be mobility information of the UE, for example, location information of initiating a TAU when the UE moves to all EPCs, or location information of initiating a TAU when the UE moves to a location that does not support a connectionless attached EPC, and optionally, the location information may be indicated by an AMF ID; the subscribed information may also be probability statistics analysis information made by the NWDAF based on the UE movement information. The PCF subscribes to a different service from the NWDAF, i.e., the EPC information requested by the PCF from the NWDAF may be at least one of mobility information or probabilistic analysis information.

And 3, the NWDAF sends the information requested by the AMF to the AMF.

The NWDAF collects mobility information of the UE, where the mobility information may be an identity of a cell where the UE is located, or an AMF ID, geographical location information from a third-party application, mobility pattern (mobility pattern), and the like, and the mobility information may include one or more of the above. Where mobility mode is a concept used by the AMF to characterize and optimize UE mobility. The AMF determines and updates a mobility pattern of the UE based on subscription of the UE, UE mobility statistics, network local policy and UE assistance information, or any combination thereof. The statistics of UE mobility may be historical or expected UE movement trajectories. The AMF may use the UE mobility patterns to optimize mobility support provided to the UE, e.g., registration area allocation. All the collected mobile information forms big data, and the NWDAF can perform statistics according to the big data to obtain the mobile rule of each UE, so as to obtain the probability that the UE moves to one or more EPCs to initiate a TAU. Further, the UE may also perform statistics, and may perform statistics on the probability that each UE moves to a specific EPC to initiate TAU when moving to a specific EPC at a specific time period and/or a specific location. The NWDAF carries out statistical analysis on the big data to obtain the probability, so that the processing resources of the PCF can be saved, and the accuracy of PCF judgment is improved.

And 4, when the UE is in an idle state, the AMF pages the UE after determining that the last PDU session is released. Wherein the specified position is a position indicated by position information contained in the trigger.

And 5, the AMF pages the UE, the UE receives the paging to synchronize the session states of the UE and the EPC, and the UE executes the attachment process when moving to the EPC. By the embodiment, the UE directly performs the attachment execution when moving to the EPC, thereby reducing the time delay of an air interface.

The communication method according to the embodiment of the present application is described in detail above with reference to fig. 1 to 11, and the network element according to the embodiment of the present application is described below with reference to fig. 12.

Fig. 12 is a schematic block diagram of an apparatus 1200 of an embodiment of the application. It should be understood that the apparatus 1200 is capable of performing the various steps performed by the first communication entity in the methods of fig. 5-11, and will not be described in detail herein to avoid repetition. The apparatus 1200 includes: a processing unit 1201 and a transceiving unit 1202.

The transceiver unit 1202 is configured to receive capability information of a terminal apparatus, and send a request message to a second communication entity, where the request message is used to request EPC information; the EPC information is information of an EPC which the terminal device can access; the EPC information is also used for receiving the EPC information sent by the second communication entity;

the processing unit 1201 is configured to determine whether to release the PDU session at least according to the EPC information.

Fig. 13 is a schematic block diagram of an apparatus 1300 of an embodiment of the present application. It should be understood that the apparatus 1300 is capable of performing the steps of the method of fig. 5-11 performed by the second communication entity and will not be described in detail herein to avoid repetition. The apparatus 1300 includes: a processing unit 1301 and a transceiving unit 1302.

The transceiver 1302 is configured to receive mobility information of a user equipment, where the mobility information is information that the user equipment moves among a plurality of EPCs;

the processing unit 1301 determines, according to the movement information, a possibility that the user equipment may move each EPC.

The transceiving unit 1302 is further configured to transmit the requested information to the first communication entity.

In the embodiments provided in the present application, the method for determining parameters provided in the embodiments of the present application is introduced from the perspective of each network element itself and from the perspective of interaction between network elements. It is to be understood that each network element, such as a terminal device (e.g., UE), a network device (e.g., base station), etc., contains corresponding hardware structures and/or software modules for performing each function in order to implement the above-mentioned functions. Those of skill in the art would readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

Based on the same inventive concept, the embodiment of the present application further provides a communication entity 1400, as shown in fig. 11, the communication entity 1400 at least includes a processor 1401 and a memory 1402, and further may further include a transceiver 1403, and may further include a bus 1404.

The processor 1401, the memory 1402, and the transceiver 1403 are all connected by a bus 1404;

the memory 1402 for storing computer-executable instructions;

the processor 1401 configured to execute the computer executable instructions stored in the memory 1402;

when the communication entity 1400 is the first communication entity in the foregoing embodiments, the processor 1401 executes the computer-executable instructions stored in the memory 1402, so that the communication entity 1400 performs the steps performed by the first communication entity in any of the foregoing embodiments provided in this application, or causes the communication entity to deploy the functional units corresponding to the steps.

When the communication entity 1400 is the second communication entity in the foregoing embodiments, the processor 1401 executes the computer executable instruction stored in the memory 1402, so that the communication entity 1400 performs the steps performed by the third communication entity in any of the foregoing embodiments provided in this application, or causes the communication entity to deploy the functional unit corresponding to the steps.

Processors 1401, which may comprise different types of processors 1401, or which may comprise the same type of processors 1401; processor 1401 may be any of the following: the system comprises a Central Processing Unit (CPU), an ARM processor (Advanced RISC Machines, Reduced Instruction Set Computing, Chinese translation into a Reduced Instruction Set), a Field Programmable Gate Array (FPGA), a special processor and other devices with Computing and Processing capabilities. In an alternative embodiment, the processor 1401 may be integrated as a many-core processor.

Memory 1402 may be any one or any combination of the following: random Access Memory (RAM), Read Only Memory (ROM), non-volatile Memory (NVM), Solid State Disk (SSD), mechanical hard disk, magnetic disk, and disk array.

The bus 1404 may include an address bus, a data bus, a control bus, etc., which is represented by a thick line in fig. 14 for ease of illustration. Bus 1404 may be any one or any combination of the following: industrial Standard Architecture (ISA) bus, Peripheral Component Interconnect (PCI) bus, Extended ISA (Extended Industry Standard Architecture) bus, and other wired data transmission devices.

The embodiment of the application provides a computer readable storage medium, wherein a computer execution instruction is stored in the computer readable storage medium; the processor of the terminal device executes the computer-executable instruction, so that the communication entity executes the step executed by the first communication entity in the above parameter determination method provided by the present application, or the communication entity deploys the functional unit corresponding to the step.

The embodiment of the application provides a computer readable storage medium, wherein a computer execution instruction is stored in the computer readable storage medium; the processor of the communication entity executes the computer-executable instructions, so that the communication entity executes the steps executed by the third communication entity in the above-mentioned parameter determination method provided by the present application, or so that the communication entity deploys the functional units corresponding to the steps.

Embodiments of the present application provide a computer program product comprising computer executable instructions stored in a computer readable storage medium. The processor of the communication entity may read the computer executable instructions from the computer readable storage medium; the processor executes the computer execution instruction, so that the terminal device executes the steps performed by the first communication entity in the above method provided by the embodiment of the present application, or the communication entity deploys the functional unit corresponding to the steps.

Embodiments of the present application provide a computer program product comprising computer executable instructions stored in a computer readable storage medium. The processor of the communication entity may read the computer executable instructions from the computer readable storage medium; the processor executes the computer-executable instructions to enable the communication entity to execute the steps executed by the third communication entity in the above-mentioned method provided by the embodiment of the present application, or to enable the communication entity to deploy the functional unit corresponding to the steps.

The present application further provides a system-on-chip comprising a processor for enabling a communication entity to carry out the functions referred to in the above aspects, e.g. to generate, receive or process data and/or information referred to in the above methods. In one possible design, the system-on-chip further includes a memory operable to store program instructions and data necessary for the terminal device. The chip system may be constituted by a chip, or may include a chip and other discrete devices.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions described in accordance with the present application are generated, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic cable, Digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that a computer can store or a data storage device including a server, a data center, etc. integrated with one or more available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

Those skilled in the art will also appreciate that the various illustrative logical blocks and steps (step) set forth herein may be implemented in electronic hardware, computer software, or combinations of both. Whether such functionality is implemented as hardware or software depends upon the particular application and design requirements of the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The various illustrative logical units and circuits described herein may be implemented or operated by a general purpose processor, a digital signal processor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, or any combination thereof. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration.

The steps of a method or algorithm described in this application may be embodied directly in hardware, in a software element executed by a processor, or in a combination of the two. The software unit may be stored in a Random-Access Memory (RAM), a flash Memory, a Read-Only Memory (ROM), an Erasable Programmable Read-Only Memory (EPROM), a register, a hard disk, a removable disk, a Compact Disc Read-Only Memory (CD-ROM), or any other storage medium in the art. For example, a storage medium may be coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC, which may be located in a terminal device or a network device. In the alternative, the processor and the storage medium may reside as discrete components in a terminal device or network device.

In one or more exemplary designs, the functions described herein may be implemented in hardware, software, firmware, or any combination of the three. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media that facilitate transfer of a computer program from one place to another. Storage media may be any available media that can be accessed by a general purpose or special purpose computer. For example, such computer-readable media can include, but is not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store program code in the form of instructions or data structures and which can be read by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Additionally, any connection is properly termed a computer-readable medium, and, thus, is included if the software is transmitted from a website, server, or other remote source over a coaxial cable, fiber optic computer, twisted pair, Digital Subscriber Line (DSL), or wirelessly, e.g., infrared, radio, and microwave. The disk (disk) and Disc (Disc) include compact Disc, laser Disc, optical Disc, Digital Versatile Disc (DVD), floppy disk and blu-ray Disc, where the disk usually reproduces data magnetically, and the Disc usually reproduces data optically with laser. Combinations of the above may also be included in the computer-readable medium.

Those skilled in the art will recognize that in one or more of the examples described above, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.

The above-mentioned embodiments, objects, technical solutions and advantages of the present application are further described in detail, it should be understood that the above-mentioned embodiments are only examples of the present application, and are not intended to limit the scope of the present application, and any modifications, equivalent substitutions, improvements and the like made on the basis of the technical solutions of the present application should be included in the scope of the present application. The foregoing description of the specification may enable any person skilled in the art to make or use the teachings of the present application, and any modifications based on the disclosed teachings should be considered as obvious in the art, and the general principles described herein may be applied to other variations without departing from the spirit or scope of the present application. Thus, the disclosure is not intended to be limited to the embodiments and designs described, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing system switching, the method comprising:

a first communication entity receiving capability information of a terminal device; wherein the capability information of the terminal device includes at least information indicating whether the UE supports connectionless attachment;

the first communication entity sends a request message to a second communication entity according to the capability information of the terminal device, wherein the request message is used for requesting Evolved Packet Core (EPC) information; the EPC information is information of an EPC which the terminal device can access;

the first communication entity receives the EPC information sent by the second communication entity;

the first communication entity determining whether to release a packet data unit, PDU, session based at least on the EPC information;

the first communication entity is a policy control function PCF, and the second communication entity is a network data analysis function NWDAF.

2. The method of claim 1, wherein the first communication entity determining whether to release a Packet Data Unit (PDU) session based at least on the EPC information comprises:

the first communication entity generates policy information at least according to the EPC information;

the first communication entity sends the policy information to a third communication entity, wherein the third communication entity is an interworking Session Management Function (SMF);

and the first communication entity receives the PDU session of the terminal device reported by the third communication entity when the strategy information is met.

3. The method according to claim 2, wherein the first communication entity updates the policy information according to information reported by a fourth communication entity, and the fourth communication entity is an access or mobility management function (AMF).

4. A method according to any of claims 1 to 3, wherein the first communication entity determines whether to release the PDU session based on at least one of the EPC information and status information, the status information comprising a time status or a location status of a terminal device.

5. The method according to any one of claims 1 to 3,

and when the first communication entity determines not to release the PDU session, the first communication entity sends a rejection message to a third communication entity.

6. The method according to any one of claims 1 to 3,

and the first communication entity determines to release the PDU session, and when the terminal device is in an idle state, the first communication entity pages the terminal device.

7. A communication apparatus, characterized in that the apparatus is configured to perform the system switching method according to any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that,

the computer-readable storage medium stores a computer program which, when executed by a computer device, is capable of implementing the method of any one of claims 1 to 6.