CN110831091B

CN110831091B - Method and equipment for activating PDU session

Info

Publication number: CN110831091B
Application number: CN201810917342.8A
Authority: CN
Inventors: 王胡成
Original assignee: Datang Mobile Communications Equipment Co Ltd
Current assignee: Datang Mobile Communications Equipment Co Ltd
Priority date: 2018-08-13
Filing date: 2018-08-13
Publication date: 2021-10-01
Anticipated expiration: 2038-08-13
Also published as: CN110831091A; WO2020034802A1

Abstract

The invention relates to the technical field of wireless communication in the technical field, in particular to a method and equipment for activating a PDU session, which are used for solving the problem that no clear solution exists for how to activate the PDU session of a service delay sensitive service. An AMF entity receives a request message sent by UE; determining an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity; and informing the SMF entity to recover the user plane connection for establishing the always-on PDU session. Because the embodiment of the invention informs the SMF entity to recover the user plane connection of the always-on PDU session, when the UE needs to transmit the uplink and downlink data on the always-on PDU session, the user plane connection of the PDU session does not need to be requested to be established again, thereby reducing the time delay and further improving the system performance.

Description

Method and equipment for activating PDU session

Technical Field

The present invention relates to the field of wireless communications technologies, and in particular, to a method and an apparatus for activating a PDU session.

Background

A Packet Data Unit (PDU) session is a session between a terminal and a Data Network (DN) to provide a PDU connectivity service. The PDU connectivity service refers to a service that provides PDU exchange between a terminal and a DN determined by a Data Network Name (DNN).

In current 5G systems, the active feature of selective PDU sessions is supported, i.e. when multiple PDU sessions are established for a User Equipment (UE), an active part of the PDU session can be selected. For a UE supporting a low-latency high-reliability service or an internet protocol Multimedia Subsystem (IMS) service, since the low-latency high-reliability service and the IMS service are delay-sensitive services, in order to reduce a delay of recovering the delay-sensitive service, when the UE enters a connected state from an idle state, even if there is no uplink or downlink data transmission on a PDU session serving the delay-sensitive service, the PDU session may be selectively activated. However, in the prior art, there is no clear solution for activating a PDU session for service delay sensitive traffic when there is no uplink or downlink data transmission on such a PDU session.

In summary, there is currently no clear solution for how to activate a PDU session for service delay sensitive traffic.

Disclosure of Invention

The invention provides a method and equipment for activating a PDU session, which are used for solving the problem that no clear solution exists for how to activate the PDU session of a service delay sensitive service in the prior art.

Based on the foregoing problem, in a first aspect, an embodiment of the present invention provides a method for activating a PDU session, including:

an AMF entity receives a request message sent by UE; wherein the request message is used for requesting to activate a PDU session of the UE;

the AMF entity determines an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity;

and the AMF entity informs the SMF entity to recover the user plane connection for establishing the always-on PDU session.

Optionally, the request message includes indication information for indicating activation of a PDU session; or

The request message contains a list of PDU sessions that need to be activated.

Optionally, the AMF entity determines the always-on PDU session corresponding to the UE according to the following manner:

if the request message is not only used for indicating to activate the control plane signaling connection, or the request message contains the indication information, the AMF entity takes the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE;

and if the activation request message contains the list of the PDU sessions needing to be activated, the AMF entity takes the always-on PDU session in the list of the always-on PDU session and recorded in the context information of the UE as the always-on PDU session corresponding to the UE.

Optionally, the method further includes:

and the AMF entity refuses to activate the always-on PDU session which is not recorded in the context information of the UE and is in the list of the PDU sessions needing to be activated, and informs the UE of the refused to activate the always-on PDU session.

Optionally, before the AMF entity receives the request message sent by the UE, the method further includes:

in the PDU session establishment process of the UE, the AMF entity determines that the PDU session established for the UE is an always-on PDU session;

and the AMF entity records the determined always-on PDU session in the context information of the UE.

Optionally, the AMF entity determines that the PDU session established for the UE is an always-on PDU session according to the following manner:

the AMF entity determines that the PDU session established for the UE is an always-on PDU session according to the subscription information of the UE and the PDU session establishment request message sent by the UE in the PDU session establishment process; or

And the AMF entity receives the indication sent by the SMF entity and determines that the PDU session established for the UE is the always-on PDU session.

Optionally, the indication sent by the SMF entity is sent after the SMF entity determines that the PDU session established for the UE is an always-on PDU session according to at least one of a locally configured network policy, a session management policy sent by a PCF entity, subscription information of the UE, and the PDU session establishment request message.

In a second aspect, an embodiment of the present invention provides a method for activating an always-on PDU session, where the method includes:

the SMF entity receives the notification of the AMF entity; the notification is sent after the AMF entity determines the always-on PDU session corresponding to the UE according to a request message sent by the UE and/or the context information of the UE maintained by the AMF entity;

and the SMF entity restores the user plane connection for establishing the always-on PDU session.

Optionally, before the SMF entity receives the notification of the AMF entity, the method further includes:

in the PDU session establishment process of the UE, the SMF entity determines that the PDU session established for the UE is an always-on PDU session;

and the SMF entity records the always-on PDU session in the context information of the UE and sends an indication that the PDU session established for the UE is the always-on PDU session to the AMF entity.

Optionally, the SMF entity determines that the PDU session established for the UE is an always-on PDU session according to the following manner:

the SMF entity determines that the PDU session established for the UE is an always-on PDU session according to at least one of a locally configured network strategy, a session management strategy sent by a PCF entity and subscription information of the UE and a PDU session establishment request message sent by the UE in the PDU session establishment process.

In a third aspect, an embodiment of the present invention provides a method for activating an always-on PDU session, where the method includes:

the UE determines that PDU conversation needs to be activated;

and the UE sends a request message for requesting to activate the PDU session to the AMF entity, so that the AMF entity determines the always-on PDU session corresponding to the UE after receiving the request message, and informs the SMF entity to restore the establishment of the user plane connection of the always-on PDU session.

The request message contains a list of PDU sessions that need to be activated.

Optionally, the sending, by the UE, a request message for requesting activation of a PDU session to the AMF entity includes:

the UE sends a request message for requesting to activate the PDU session to the AMF entity in the service request process; or

And the UE sends a request message for requesting to activate the PDU session to the AMF entity in the registration updating process.

In a fourth aspect, an embodiment of the present invention provides an access and mobility management AMF entity, including: a processor, a memory;

the processor is used for reading the program in the memory and executing:

receiving a request message sent by UE; wherein the request message is used for requesting to activate a PDU session of the UE;

determining an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity;

and informing the SMF entity to recover the user plane connection for establishing the always-on PDU session.

The request message contains a list of PDU sessions that need to be activated.

Optionally, the processor is specifically configured to:

if the request message is not only used for indicating to activate the control plane signaling connection, or the request message contains the indication information, taking the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE;

and if the activation request message contains the list of the PDU sessions needing to be activated, taking the always-on PDU session in the list of the always-on PDU session and recorded in the context information of the UE as the always-on PDU session corresponding to the UE.

Optionally, the processor is further configured to:

and refusing to activate the always-on PDU session which is not recorded in the context information of the UE in the list of the PDU sessions needing to be activated, and informing the UE of the refused to activate the always-on PDU session.

Optionally, the processor is further configured to:

before receiving a request message sent by UE, determining that a PDU session established for the UE is an always-on PDU session in the PDU session establishment process of the UE;

and recording the determined always-on PDU session in the context information of the UE.

Optionally, the processor is specifically configured to:

determining that the PDU session established for the UE is an always-on PDU session according to the following modes:

determining that the PDU session established for the UE is an always-on PDU session according to the subscription information of the UE and a PDU session establishment request message sent by the UE in the PDU session establishment process; or

And receiving the indication sent by the SMF entity to determine that the PDU session established for the UE is the always-on PDU session.

In a fifth aspect, an embodiment of the present invention provides a session management function SMF entity, including: a processor, a memory;

the processor is used for reading the program in the memory and executing:

receiving a notification of an AMF entity; the notification is sent after the AMF entity determines the always-on PDU session corresponding to the UE according to a request message sent by the UE and/or the context information of the UE maintained by the AMF entity;

and restoring the user plane connection for establishing the always-on PDU session.

Optionally, the processor is further configured to:

before receiving the notification of the AMF entity, determining that the PDU session established for the UE is an always-on PDU session in the PDU session establishment process of the UE;

and recording the always-on PDU session in the context information of the UE, and sending an indication that the PDU session established for the UE is the always-on PDU session to the AMF entity.

Optionally, the processor is specifically configured to:

and determining that the PDU session established for the UE is an always-on PDU session according to at least one of a locally configured network strategy, a session management strategy sent by a PCF entity and subscription information of the UE and a PDU session establishment request message sent by the UE in the PDU session establishment process.

In a sixth aspect, an embodiment of the present invention provides a user equipment UE, including: a processor, a memory;

the processor is used for reading the program in the memory and executing:

determining that PDU session needs to be activated;

sending a request message for requesting to activate the PDU session to the AMF entity, so that the AMF entity determines the always-on PDU session corresponding to the UE after receiving the request message, and informing the SMF entity to restore the establishment of the user plane connection of the always-on PDU session.

The request message contains a list of PDU sessions that need to be activated.

Optionally, the processor is specifically configured to:

in the service request process, sending a request message for requesting to activate the PDU session to the AMF entity; or

And in the registration updating process, sending a request message for requesting to activate the PDU session to the AMF entity.

In a seventh aspect, an embodiment of the present invention provides an access and mobility management AMF entity, including:

a first receiving module, configured to receive a request message sent by a UE; wherein the request message is used for requesting to activate a PDU session of the UE;

a first determining module, configured to determine an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity;

and the notification module is used for notifying the SMF entity to recover the user plane connection for establishing the always-on PDU session.

In an eighth aspect, an embodiment of the present invention provides a session management function SMF entity, including:

a second receiving module, configured to receive a notification of the AMF entity; the notification is sent after the AMF entity determines the always-on PDU session corresponding to the UE according to a request message sent by the UE and/or the context information of the UE maintained by the AMF entity;

and the processing module is used for recovering the user plane connection for establishing the always-on PDU session.

In a ninth aspect, an embodiment of the present invention provides a user equipment UE, including:

the second determining module is used for determining that the PDU session needs to be activated;

a sending module, configured to send a request message for requesting activation of a PDU session to the AMF entity, so that the AMF entity determines an always-on PDU session corresponding to the UE after receiving the request message, and notifies the SMF entity to restore a user plane connection for establishing the always-on PDU session.

In a tenth aspect, embodiments of the present invention provide a computer-readable medium on which a computer program is stored, the program, when executed by a processor, implementing the steps of the method according to any one of the first aspect, the steps of the method according to any one of the second aspect, or the steps of the method according to any one of the third aspect.

After receiving the request message, the AMF entity determines the always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE, and informs the SMF entity to recover the user plane connection of the always-on PDU session; therefore, when the UE needs to transmit the uplink data and the downlink data on the always-on PDU session, the user plane connection of the PDU session does not need to be established again, so that the time delay can be reduced, and the system performance is further improved.

Drawings

FIG. 1 is a system architecture diagram according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a PDU session activation system according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating a first SMF entity determining whether a PDU session is an always-on PDU session according to an embodiment of the present invention;

fig. 4 is a flowchart illustrating a second SMF entity determining whether a PDU session is an always-on PDU session according to an embodiment of the present invention;

FIG. 5 is a flowchart illustrating a first method for activating a PDU session according to an embodiment of the present invention;

FIG. 6 is a flowchart illustrating a second method for activating a PDU session according to a second embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a first AMF entity according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a first SMF entity according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a first UE according to an embodiment of the present invention;

FIG. 10 is a diagram illustrating a second AMF entity according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of a second SMF entity according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of a second UE according to an embodiment of the present invention;

fig. 13 is a flowchart of a first method for activating a PDU session according to an embodiment of the present invention;

FIG. 14 is a flowchart of a second method for activating a PDU session according to a second embodiment of the present invention;

fig. 15 is a flowchart of a third method for activating a PDU session according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The present invention will be described in further detail below with reference to the accompanying drawings.

Fig. 1 illustrates a schematic diagram of a system architecture suitable for an embodiment of the present invention, as shown in fig. 1, in a future 5G system architecture, a terminal 101 may communicate with a core network via an access network entity 102, and the terminal may refer to a UE, 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 equipment. An access terminal may be a cellular telephone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with Wireless communication capabilities, a computing device or other processing device connected to a Wireless modem, a vehicle mounted device, a wearable device, a terminal in a future 5G network, etc. For convenience of description, fig. 1 only illustrates 1 terminal, and in an actual network, multiple terminals may coexist, which is not described herein again.

AN Access Network (AN) entity 102, which may also be referred to as a Radio Access Network (R) entity, hereinafter referred to as AN Access Network entity (R) AN entity, is mainly responsible for providing a wireless connection for the terminal 101, and ensuring reliable transmission of uplink and downlink data of the terminal 101. The Access network entity 102 may be a gbb (generation Node B) in a 5G System, a Base Transceiver Station (BTS) in a Global System for Mobile communications (GSM) System or a Code Division Multiple Access (CDMA) System, a Base Station NodeB, NB in a Wideband Code Division Multiple Access (WCDMA) System, an evolved Base Station (eNB, eNodeB) in a Long Term Evolution (Long Term Evolution, LTE) System, or the like.

A Session Management Function (SMF) Entity 103, which may be configured to perform a part of functions of a Mobility Management Entity (MME) in the LTE system, and is mainly responsible for establishing a Session, managing the Session, and the like for the terminal 101. A suitable User Plane Function (UPF) entity may be selected for the terminal 101 according to the location information of the terminal 101.

The user plane functional entity 104 is a functional network element of the user plane of the terminal 101, and has main functions including packet routing and forwarding, Quality of Service (QoS) processing of user plane data, and the like.

An Access and Mobility Management Function (AMF) entity 105 mainly includes a termination point of a radio Access network control plane, a termination point of a non-Access signaling, Mobility Management, lawful interception, Access authorization or authentication, and the like.

A Policy Control Function (PCF) entity 106 is mainly responsible for the functions of establishing, releasing, and changing the transmission path of the user plane.

An Authentication Server Function (AUSF) entity 107, whose main functions include user Authentication and the like.

A User Data Management (UDM) entity 108 is mainly responsible for managing the subscription Data of the User, and the like.

The Data Network (DN) 109 may refer to a Network providing services for the terminal 101, for example, some DNs may provide an internet function for the terminal 101, and some DNs may provide a multimedia message function for the terminal 101.

It should be noted that the above system architecture is only an example of the system architecture applicable to the embodiment of the present invention, and the system architecture applicable to the embodiment of the present invention may also add other entities or reduce part of the entities compared to the system architecture shown in fig. 1.

A PDU session is a connection between a terminal and a DN, providing a PDU connectivity service. The terminal may establish multiple PDU sessions to connect to the same DN or different DNs. The terminal may also establish PDU sessions served by different UPFs to connect to the same DN.

The state of the PDU session includes at least active and Inactive states (Inactive or de-activated).

The active state refers to a state that the user plane resources of the PDU session are already established, an end-to-end connection is established between the terminal and the DN, and data can be transferred through the PDU session. The inactive state means that the PDU session only reserves part of the user plane resources, but the user plane air interface resources between the terminal and the (R) AN entity and the connection between the (R) AN entity and the UPF entity are not established, and the terminal and the DN cannot transfer data, but the SMF entity and the UPF entity still reserve part of the information of the PDU session.

When the UE is in an idle state, the state of the PDU session established for the UE is in an inactive state; and when the UE has uplink or downlink data transmission, activating the PDU session of the UE. However, for a delay-sensitive service, if a PDU session serving the service is reactivated each time delay-sensitive service data needs to be transmitted, the delay may be increased; therefore, the embodiment of the present invention provides a method for setting a PDU session for serving a delay sensitive service to an always on (always on) PDU session, that is, the PDU session is activated no matter whether there is uplink or downlink data to be transmitted on the PDU session, so that when data of the delay sensitive service needs to be transmitted, the delay can be greatly reduced; specifically, the UE sends a request to the network side requesting the network side to activate the always-on PDU session.

In the embodiment of the invention, the always-on (always on) PDU session is the PDU session in which the UE entering the connected state always keeps the user interface connection in the life cycle of the PDU session.

The SMF entity and the UPF entity may implement separate charging policies for the always-on PDU session.

In conjunction with the foregoing description, as shown in fig. 2, a system for activating a PDU session according to an embodiment of the present invention includes: UE 20, AMF entity 21, SMF entity 22;

wherein, the UE 20 is configured to determine that a PDU session needs to be activated; sending a request message for requesting to activate the PDU session to the AMF entity, so that the AMF entity determines the always-on PDU session corresponding to the UE after receiving the request message, and informing the SMF entity to restore the establishment of the user plane connection of the always-on PDU session.

An AMF entity 21, configured to receive a request message sent by UE 20; wherein the request message is used for requesting to activate a PDU session of the UE; determining an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity; and informing the SMF entity to recover the user plane connection for establishing the always-on PDU session.

An SMF entity 22 for receiving a notification of the AMF entity; the notification is sent after the AMF entity determines the always-on PDU session corresponding to the UE according to a request message sent by the UE and/or the context information of the UE maintained by the AMF entity; and restoring the user plane connection for establishing the always-on PDU session.

In implementation, the UE may send the request message to the AMF entity at the following occasions:

1. and the UE sends a request message for requesting to activate the PDU session to the AMF entity in the service request process.

It should be noted that, when uplink data needs to be sent on one or more PDU sessions of the UE, the UE may initiate a Service Request (Service Request) process;

the request message sent by the UE to the AMF entity in the service request process is a service request message.

2. And the UE sends a request message for requesting to activate the PDU session to the AMF entity in the registration updating process.

The request message sent by the UE to the AMF entity in the registration update process is a registration update request message.

It should be noted that, in the embodiment of the present invention, the timing for the UE to send the request message to the AMF entity is not limited to the above two, and after determining that the PDU session needs to be activated, the UE may also send the request message for requesting activation of the PDU session to the AMF entity in other manners.

Wherein, the request message contains indication information for indicating the activation of PDU conversation; or

The request message contains a list of PDU sessions that need to be activated.

In an optional manner, when the UE sends a request message that includes a list of PDU sessions that need to be activated, the PDU session list only includes PDU sessions that have no uplink data transmission;

since the UE needs to request the AMF to activate the PDU session with uplink data transmission when sending the request message to the AMF entity in the service request process, the UE needs to send the list of PDU sessions with uplink data transmission to the AMF entity.

After receiving a request message sent by UE, an AMF entity determines an always-on PDU session corresponding to the UE according to indication information in the request message or a PDU session list needing to be activated;

in implementation, the AMF entity determines an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity;

specifically, if the request message sent by the UE includes indication information for indicating activation of the PDU session, the AMF entity determines the always-on PDU session corresponding to the UE according to the maintained context information of the UE;

if the request message sent by the UE contains the list of the PDU session needing to be activated, the AMF entity determines the always-on PDU session corresponding to the UE according to the list of the PDU session needing to be activated and the context information of the UE maintained by the AMF entity.

And when determining the always-on PDU session corresponding to the UE according to the context information of the UE, the AMF entity determines the always-on PDU session corresponding to the UE according to the always-on PDU session recorded in the context of the UE.

After determining the always-on PDU session corresponding to the UE, the AMF entity informs the SMF entity to restore the establishment of the user plane connection of the always-on PDU session corresponding to the UE;

it should be noted here that the always-on PDU session corresponding to the UE determined by the AMF entity is the always-on PDU session that the AMF entity determines to allow activation; when the AMF entity determines that the activation of the always-on PDU session is allowed, whether the PDU session of the UE is the always-on PDU session allowed to be activated or not is judged according to the mobility restriction information; for example, the mobility restriction information is whether the UE enters a non-allowed area, and when the UE enters the non-allowed area, the PDU session of the UE cannot be activated.

Context information of the UE is maintained in the AMF entity of the embodiment of the invention; and in the process of establishing the PDU session, the AMF entity judges whether the PDU session is the always-on PDU session, and if so, records the always-on PDU session in the context information of the UE.

The method for determining the always-on PDU session recorded in the UE context information by the AMF entity according to the embodiment of the present invention is described in detail below.

Optionally, in the PDU session establishment process of the UE, the AMF entity determines that the PDU session established for the UE is an always-on PDU session; and the AMF entity records the determined always-on PDU session in the context information of the UE.

For any PDU session established for the UE, in the establishment process of the PDU session, the AMF entity judges whether the PDU session is an always-on PDU session, and if so, the AMF entity marks the PDU session as the always-on PDU session in the context information of the UE.

Specifically, the embodiments of the present invention provide several ways for the AMF entity to determine whether the PDU session established for the UE is an always-on PDU session, which are described below.

In the first mode, the AMF entity determines that the PDU session established for the UE is the always-on PDU session according to the subscription information of the UE and the PDU session establishment request message sent by the UE in the PDU session establishment process.

The subscription information of the UE comprises S-NSSAI and/or DNN information;

in the process of establishing PDU session for UE, the PDU session needs to be established by using S-NSSAI and/or DNN information in subscription information;

and, for any one PDU session established for the UE, displaying or indicating whether the PDU session is an always-on PDU session in S-NSSAI and/or DNN information used to establish the PDU session.

In the process that the UE registers in the network, the AMF entity acquires subscription information of the UE, wherein the acquired subscription information comprises S-NSSAI and/or DNN information;

and in the PDU session establishment process, the PDU session is established for the UE by using the S-NSSAI and/or DNN information included in the subscription information of the UE.

When the AMF entity judges whether the PDU session established by the UE is the always-on PDU session, the AMF entity judges whether the PDU session is the always-on PDU session according to the S-NSSAI and/or DNN information used for establishing the PDU session;

if the AMF entity determines that the PDU session established for the UE is the always-on PDU session, the AMF entity records the PDU session as the always-on PDU session in the context information of the UE maintained by the AMF entity.

And in the second mode, the AMF entity receives the indication sent by the SMF entity and determines that the PDU session established for the UE is the always-on PDU session.

In the second mode, the indication sent by the SMF entity to the AMF entity is sent to the AMF entity after the SMF entity determines that the PDU session established for the UE is the always-on PDU session.

It should be noted that, in the second method, the SMF entity determines whether the PDU session established for the UE is an always-on PDU session.

Optionally, the indication sent by the SMF entity is sent after the PDU session established for the UE is determined to be an always-on PDU session by the SMF entity according to at least one of a locally configured network policy, a session management policy sent by the PCF entity, subscription information of the UE, and the PDU session establishment request message.

The SMF entity of the embodiment of the invention can judge whether the PDU session established for the UE is the always-on PDU session by adopting the following modes:

in the mode 1, the SMF entity judges whether the PDU session established by the UE is the always-on PDU session according to the subscription information of the UE and the PDU session establishment request message.

In the PDU session establishment process, the PDU session is established for the UE by using S-NSSAI and/or DNN information included in the subscription information of the UE; when the SMF entity performs session management subscription check, the subscription information of the UE can be acquired from the UDM entity, wherein the acquired subscription information comprises S-NSSAI and/or DNN information;

the SMF entity judges whether the PDU session is an always-on PDU session according to the subscription information of the UE and the PDU session establishment request message;

if the SMF entity determines that the PDU session established for the UE is the always-on PDU session, the SMF entity records the PDU session as the always-on PDU session in the self-maintained context information of the UE.

After determining that the PDU session is the always-on PDU session, the SMF entity sends an indication to the AMF entity to inform the AMF entity that the PDU session is the always-on PDU session.

As shown in fig. 3, a flowchart of a first SMF entity determining whether a PDU session established for a UE is an always-on PDU session according to an embodiment of the present invention is shown.

Step 301, the UE sends a PDU session establishment request message to the AMF entity;

step 302, the AMF entity forwards a PDU session establishment request message sent by the UE to the SMF entity;

step 303, the SMF entity acquires subscription information of the UE from the UDM entity;

step 304, the SMF entity judges whether the PDU session established by the UE is the always-on PDU session according to the PDU session establishment request message and the subscription information of the UE;

305, the SMF entity sends an indication that the PDU session established for the UE is the always-on PDU session to the AMF entity;

it should be noted that, in step 305, the SMF entity sending the indication indicating that the PDU session established for the UE is the always-on PDU session to the AMF entity is only an optional way, and in addition, the SMF entity may also send an indication to the AMF entity when determining that the PDU session established for the UE is not the always-on PDU session, so as to notify that the PDU session established for the UE is not the always-on PDU session;

step 306, the AMF entity records the PDU session established for the UE in the context information of the UE as an always-on PDU session.

And 2, the SMF entity judges whether the PDU session established for the UE is the always on-line PDU session or not according to the session management strategy and the PDU session establishment request message sent by the PCF entity.

In the PDU session establishment process, the correlation is established between the SMF entity and the PCF entity; the PCF entity judges whether the PDU session established for the UE is an always-on PDU session; and after the PCF entity determines that the PDU session established for the UE is the always-on PDU session, sending a session management strategy to the SMF, wherein the session management strategy is used for indicating that the PDU session established for the UE is the always-on PDU session.

Specifically, the PCF entity determines that the PDU session established by the UE is an always-on PDU session according to part or all of the following information:

operator policy, subscription information of the UE, and auxiliary information of the UE;

the auxiliary information of the UE includes but is not limited to: preferences of the UE, setting information of the UE.

After the SMF entity determines that the PDU session is the always-on PDU session according to the session management strategy and the PDU session establishment request message sent by the PCF entity, an indication is sent to the AMF entity to inform the AMF entity that the PDU session is the always-on PDU session.

As shown in fig. 4, a flowchart of a second SMF entity according to the embodiment of the present invention determining whether a PDU session established for a UE is an always-on PDU session.

Step 401, UE sends PDU conversation establishment request message to AMF entity;

step 402, the AMF entity forwards a PDU session establishment request message sent by the UE to the SMF entity;

step 403, establishing association between the SMF entity and the PCF entity;

step 404, the PCF entity judges that the PDU session established by the UE is an always-on PDU session;

step 405, PCF entity sends session management strategy to SMF entity according to the judgment result;

wherein, the session management policy is used to indicate whether the PDU session established for the UE is an always-on PDU session;

step 406, the SMF entity determines whether the PDU session established for the UE is an always on-line PDU session according to the session management policy and the PDU session establishment request message sent by the PCF entity;

it should be noted that, when the PCF entity determines that the PDU session established for the UE is an always-on PDU session, the PCF entity sends a session management policy indicating that the PDU session established for the UE is an always-on PDU session to the SMF entity, so that after receiving the session management policy sent by the PCF entity, the SMF entity determines whether the PDU session established for the UE is an always-on PDU session according to the session management policy and the PDU session establishment request message;

step 407, the SMF entity sends an indication that the PDU session established for the UE is an always-on PDU session to the AMF entity;

it should be noted that, in step 407, the SMF entity sending the indication indicating that the PDU session established for the UE is the always-on PDU session to the AMF entity is only an optional way, and in addition, the SMF entity may also send an indication to the AMF entity when determining that the PDU session established for the UE is not the always-on PDU session, so as to notify that the PDU session established for the UE is not the always-on PDU session;

step 408, the AMF entity records the PDU session established for the UE in the context information of the UE as an always-on PDU session.

And in the mode 3, the SMF entity judges whether the PDU session established for the UE is the always-on PDU session according to the locally configured network strategy.

If the SMF entity determines that the PDU session established for the UE is the always-on PDU session according to the locally configured network policy, the SMF entity records the PDU session as the always-on PDU session in the self-maintained context information of the UE.

It should be noted here that the above-mentioned manner in which the AMF entity determines that the PDU session established for the UE is the always-on PDU session is only an optional manner in the embodiment of the present invention, and in the embodiment of the present invention, the AMF entity may also determine that the PDU session established for the UE is the always-on PDU session in other manners.

In addition, the AMF entity determines the always-on PDU session corresponding to the UE in the process of establishing the PDU session for the UE, and records the PDU session established for the UE in the context information of the UE.

After receiving the request message of the UE, the AMF determines the always-on PDU session corresponding to the UE in different modes according to different request messages when determining the always-on PDU session corresponding to the UE according to the request message of the UE and/or the context information of the UE. The following description will be made separately.

Case one, if the request message is not only used to indicate the activation of the control plane signaling connection.

In this case, the AMF determines the always-on PDU session corresponding to the UE according to the following manner:

and the AMF entity takes the always-on PDU conversation recorded in the context information of the UE as the always-on PDU conversation corresponding to the UE.

For example, assume that the always-on PDU session recorded in the context information of the UE maintained by the AMF entity is: PDU session 1, PDU session 3 and PDU session 4; after receiving the request message of the UE, if it is determined that the request message is not only used for indicating activation of a control plane signaling connection, the AMF entity performs an always-on PDU session recorded in context information of the UE: and the PDU session 1, the PDU session 3 and the PDU session 4 are taken as the always-on PDU sessions corresponding to the UE.

In case two, the request message includes indication information for indicating that the PDU session is activated.

It should be noted that, in this case, the PDU session to be activated is not specified in the request message sent by the UE to the AMF entity; after receiving the request message only containing the indication information, the AMF entity takes all the always-on PDU sessions recorded in the context information of the UE maintained by the AMF entity as the always-on PDU sessions corresponding to the UE.

For example, assume that the always-on PDU session recorded in the context information of the UE maintained by the AMF entity is: PDU session 1, PDU session 2 and PDU session 4; after receiving a request message of the UE, if the AMF entity determines that the request message contains indication information for indicating activation of the always-on PDU session, the AMF entity carries out the always-on PDU session recorded in the context information of the UE: and the PDU session 1, the PDU session 2 and the PDU session 4 are taken as the always-on PDU sessions corresponding to the UE.

And in case three, the request message contains a list of the PDU sessions to be activated.

And the AMF entity takes the always-on PDU session which is in the list of the PDU sessions needing to be activated and recorded in the context information of the UE as the always-on PDU session corresponding to the UE.

In this case, the AMF entity includes a PDU session list requested to be activated by the UE in a request message sent by the UE, and selects the PDU session included in the PDU session list to be an intersection with the PDU session included in the context information of the UE, as the always-on PDU session corresponding to the UE.

For example, assume that the always-on PDU session recorded in the context information of the UE maintained by the AMF entity is: PDU session 1 and PDU session 2; the PDU session list to be activated, which is contained in the request message received by the AMF entity from the UE, is: and taking the PDU session 2, the PDU session 3 and the PDU session 4, wherein the PDU session which is always on line and is recorded in the context information of the UE and the PDU session 2 which is intersected with the PDU session in the PDU session list which needs to be activated as the PDU session which is always on line and corresponding to the UE.

In addition, the AMF entity rejects activation of the always-on PDU session which is not recorded in the context information of the UE in the list of the PDU sessions to be activated, and notifies the UE of the rejection of the activation of the always-on PDU session.

For example, assume that the always-on PDU session recorded in the context information of the UE maintained by the AMF entity is: PDU session 1 and PDU session 2; the PDU session list to be activated, which is contained in the request message received by the AMF entity from the UE, is: PDU session 2, PDU session 3 and PDU session 4; since PDU session 3 and PDU session 4 contained in the PDU session list that needs to be activated are not recorded in the context information of the UE, the AMF entity refuses to activate PDU session 3 and PDU session 4; and notifies the UE of the rejection of the activated PDU session 3 and PDU session 4.

Or, the AMF entity determines the always-on PDU session corresponding to the UE only according to the context information of the UE; specifically, after receiving the request message sent by the UE, the AMF entity uses the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE.

The following describes a method for activating a PDU session in a specific embodiment.

As shown in fig. 5, a flowchart of a first method for activating a PDU session according to an embodiment of the present invention; the request message includes indication information for indicating activation of a PDU session.

Step 501, UE sends a request message to an AMF entity;

step 502, the AMF entity takes the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE;

step 503, the AMF entity notifies the SMF entity to resume establishing the user plane connection of the always-on PDU session corresponding to the UE.

As shown in fig. 6, a flowchart of a second method for activating a PDU session according to an embodiment of the present invention; the description is given by taking the example that the request message includes the list of PDU sessions to be activated.

Step 601, UE sends request message to AMF entity;

step 602, the AMF entity uses the always-on PDU session recorded in the context information of the UE and in the list of the always-on PDU sessions as the always-on PDU session corresponding to the UE;

step 603, the AMF entity informs the SMF entity to resume establishing the user plane connection of the always-on PDU session corresponding to the UE.

As shown in fig. 7, a first access and mobility management AMF entity according to an embodiment of the present invention includes: a processor 700, a memory 701, and a bus interface.

The processor 700 is responsible for managing the bus architecture and general processing, and the memory 701 may store data used by the processor 700 in performing operations. The bus architecture may include any number of interconnected buses and bridges, particularly linked together by various circuits of the one or more processors 700 and the one or more memories 701. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The processor 700 is responsible for managing the bus architecture and general processing, and the memory 701 may store data used by the processor 700 in performing operations.

The processes disclosed in the embodiments of the present invention may be applied to the processor 700, or implemented by the processor 700. In implementation, the steps of the signal processing flow may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 700. The processor 700 may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof that may implement or perform the methods, steps or logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 701, and the processor 700 reads the information in the memory 701, and completes the steps of the signal processing flow in combination with the hardware thereof.

Specifically, the processor 700 is configured to read the program in the memory 701 and execute:

The request message contains a list of PDU sessions that need to be activated.

Optionally, the processor 700 is specifically configured to:

Optionally, the processor 700 is further configured to:

Optionally, the processor 700 is specifically configured to:

As shown in fig. 8, a first session management function SMF entity according to an embodiment of the present invention includes: a processor 800, a memory 801, and a bus interface.

The processor 800 is responsible for managing the bus architecture and general processing, and the memory 801 may store data used by the processor 800 in performing operations. The bus architecture may include any number of interconnected buses and bridges, particularly linked together by various circuits of the one or more processors 800 and the one or more memories 801. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The processor 800 is responsible for managing the bus architecture and general processing, and the memory 801 may store data used by the processor 800 in performing operations.

The processes disclosed in the embodiments of the present invention may be applied to processor 800, or implemented by processor 800. In implementation, the steps of the signal processing flow may be implemented by integrated logic circuits of hardware or instructions in the form of software in the processor 800. The processor 800 may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like that may implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 801, and the processor 800 reads the information in the memory 801 and completes the steps of the signal processing flow in combination with the hardware thereof.

Specifically, the processor 800 is configured to read the program in the memory 801 and execute:

Optionally, the processor 800 is further configured to:

Optionally, the processor 800 is specifically configured to:

As shown in fig. 9, a user equipment UE according to a first embodiment of the present invention includes: a processor 900, a memory 901, a transceiver 902, and a bus interface.

The processor 900 is responsible for managing the bus architecture and general processing, and the memory 901 may store data used by the processor 900 in performing operations. The transceiver 902 is used for receiving and transmitting data under the control of the processor 900.

The bus architecture may include any number of interconnected buses and bridges, with one or more processors, represented by processor 900, and various circuits, represented by memory 901, being linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The processor 900 is responsible for managing the bus architecture and general processing, and the memory 901 may store data used by the processor 900 in performing operations.

The processes disclosed in the embodiments of the present invention may be applied to the processor 900, or implemented by the processor 900. In implementation, the steps of the signal processing flow may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 900. The processor 900 may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like that may implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 901, and the processor 900 reads the information in the memory 901 and completes the steps of the signal processing flow in combination with the hardware thereof.

Specifically, the processor 900 is configured to read a program in the memory 901 and execute:

determining that PDU session needs to be activated;

The request message contains a list of PDU sessions that need to be activated.

Optionally, the processor 900 is specifically configured to:

As shown in fig. 10, a second AMF entity according to an embodiment of the present invention includes:

a first receiving module 1001, configured to receive a request message sent by a UE; wherein the request message is used for requesting to activate a PDU session of the UE;

a first determining module 1002, configured to determine an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity;

a notifying module 1003, configured to notify the SMF entity to resume establishing the user plane connection of the always-on PDU session.

The request message contains a list of PDU sessions that need to be activated.

Optionally, the first determining module 1002 is specifically configured to:

determining the always-on PDU session corresponding to the UE according to the following modes:

Optionally, the first determining module 1002 is further configured to:

Optionally, the first receiving module 1001 is further configured to:

before receiving a request message sent by UE, determining that a PDU session established for the UE is an always-on PDU session in the PDU session establishment process of the UE; and recording the determined always-on PDU session in the context information of the UE.

Optionally, the first determining module 1002 is specifically configured to:

As shown in fig. 11, a second SMF entity according to the embodiment of the present invention includes:

a second receiving module 1101, configured to receive a notification of an AMF entity; the notification is sent after the AMF entity determines the always-on PDU session corresponding to the UE according to a request message sent by the UE and/or the context information of the UE maintained by the AMF entity;

a processing module 1102 configured to resume establishing the user plane connection of the always-on PDU session.

Optionally, the second receiving module 1101 is further configured to:

before receiving the notification of the AMF entity, determining that the PDU session established for the UE is an always-on PDU session in the PDU session establishment process of the UE; and recording the always-on PDU session in the context information of the UE, and sending an indication that the PDU session established for the UE is the always-on PDU session to the AMF entity.

Optionally, the second receiving module 1101 is specifically configured to:

As shown in fig. 12, a UE according to a second embodiment of the present invention includes:

a second determining module 1201, configured to determine that a PDU session needs to be activated;

a sending module 1202, configured to send a request message for requesting activation of a PDU session to the AMF entity, so that the AMF entity determines an always-on PDU session corresponding to the UE after receiving the request message, and notifies the SMF entity to recover to establish a user plane connection of the always-on PDU session.

The request message contains a list of PDU sessions that need to be activated.

Optionally, the sending module 1202 is specifically configured to:

The embodiments of the present invention further provide a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of the AMF entity described above in the embodiments of the present invention, or the steps of the SMF entity described above in the embodiments of the present invention, or the steps of the UE described above in the embodiments of the present invention.

Based on the same inventive concept, the embodiment of the present invention further provides a first method for activating a PDU session, because the device corresponding to the method is an AMF entity in the system for activating a PDU session in the embodiment of the present invention, and the principle of the method for solving the problem is similar to that of the device, the implementation of the method may refer to the implementation of the device, and repeated details are omitted.

As shown in fig. 13, a first method for activating a PDU session according to an embodiment of the present invention includes:

step 1301, receiving a request message sent by the UE by the AMF entity; wherein the request message is used for requesting to activate a PDU session of the UE;

step 1302, the AMF entity determines an always-on PDU session corresponding to the UE according to the request message and/or the context information of the UE maintained by the AMF entity;

and 1303, the AMF entity notifies the SMF entity to restore the user plane connection for establishing the always-on PDU session.

The request message contains a list of PDU sessions that need to be activated.

Optionally, the method further includes:

Based on the same inventive concept, the embodiment of the present invention further provides a second method for activating a PDU session, because the device corresponding to the method is an SMF entity in the system for activating a PDU session in the embodiment of the present invention, and the principle of the method for solving the problem is similar to that of the device, the implementation of the method may refer to the implementation of the device, and repeated details are omitted.

As shown in fig. 14, a second method for activating a PDU session according to the embodiment of the present invention includes:

1401, receiving a notification of the AMF entity by the SMF entity; the notification is sent after the AMF entity determines the always-on PDU session corresponding to the UE according to a request message sent by the UE and/or the context information of the UE maintained by the AMF entity;

and 1402, the SMF entity restores the user plane connection for establishing the always-on PDU session.

Based on the same inventive concept, a third method for activating a PDU session is also provided in the embodiments of the present invention, and since the device corresponding to the method is the UE in the system for activating a PDU session in the embodiments of the present invention, and the principle of the method for solving the problem is similar to that of the device, the implementation of the method can refer to the implementation of the device, and repeated details are not repeated.

As shown in fig. 15, a third method for activating a PDU session according to an embodiment of the present invention includes:

step 1501, UE determines that PDU session needs to be activated;

step 1502, the UE sends a request message for requesting activation of a PDU session to the AMF entity, so that the AMF entity determines an always-on PDU session corresponding to the UE after receiving the request message, and notifies the SMF entity to resume establishing a user plane connection of the always-on PDU session.

The request message contains a list of PDU sessions that need to be activated.

The present application is described above with reference to block diagrams and/or flowchart illustrations of methods, apparatus (systems) and/or computer program products according to embodiments of the application. It will be understood that one block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, and/or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, create means for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.

Accordingly, the subject application may also be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.). Furthermore, the present application may take the form of a computer program product on a computer-usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. In the context of this application, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method of activating a packet data unit, PDU, session, the method comprising:

an access and mobility management function (AMF) entity receives a request message sent by User Equipment (UE); wherein the request message is used for requesting to activate a PDU session of the UE;

if the request message contains indication information for indicating activation of the PDU session, the AMF entity takes the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE;

and the AMF entity informs a Session Management Function (SMF) entity to restore the user plane connection for establishing the always-on PDU session.

2. The method of claim 1, wherein the request message includes a list of PDU sessions that need to be activated.

3. The method of claim 2, wherein the AMF entity determines the corresponding always-on PDU session for the UE according to:

4. The method of claim 3, further comprising:

5. The method of claim 1, wherein before the AMF entity receives the request message sent by the UE, further comprising:

6. The method of claim 5, wherein the AMF entity determines that the PDU session established for the UE is an always-on PDU session according to:

7. The method of claim 6, wherein the indication sent by the SMF entity is sent by the SMF entity after determining that the PDU session established for the UE is an always-on PDU session according to at least one of a locally configured network policy, a session management policy sent by a Policy Control Function (PCF) entity, subscription information of the UE, and the PDU session establishment request message.

8. A method of activating an always-on PDU session, the method comprising:

the SMF entity receives the notification of the AMF entity; the AMF entity sends the notification after taking the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE if the request message sent by the UE contains the indication information for indicating the activation of the PDU session;

9. The method of claim 8, wherein prior to the SMF entity receiving the notification of the AMF entity, further comprising:

10. The method of claim 9, wherein the SMF entity determines the PDU session established for the UE to be an always-on PDU session according to:

11. A method of activating an always-on PDU session, the method comprising:

the UE determines that PDU conversation needs to be activated;

the UE sends a request message for requesting to activate the PDU session to an AMF entity, so that after the AMF entity receives the request message, if the request message contains indication information for indicating to activate the PDU session, the always-on PDU session recorded in the context information of the UE is used as the always-on PDU session corresponding to the UE, and the SMF entity is informed to restore the establishment of the user plane connection of the always-on PDU session.

12. The method of claim 11, wherein the request message includes a list of PDU sessions that need to be activated.

13. The method of claim 11, wherein the UE transmitting a request message for requesting activation of a PDU session to the AMF entity comprises:

14. An access and mobility management, AMF, entity, comprising: a processor, a memory;

the processor is used for reading the program in the memory and executing:

15. The AMF entity of claim 14, wherein the request message includes a list of PDU sessions that need to be activated.

16. The AMF entity of claim 15, wherein the processor is specifically configured to:

17. The AMF entity of claim 16, wherein the processor is further configured to:

18. The AMF entity of claim 14, wherein the processor is further configured to:

19. The AMF entity of claim 18, wherein the processor is specifically configured to:

20. The AMF entity of claim 19, wherein the indication sent by the SMF entity is sent after the SMF entity determines that the PDU session established for the UE is an always-on PDU session based on at least one of a locally configured network policy, a session management policy sent by a PCF entity, subscription information of the UE, and the PDU session establishment request message.

21. A session management function, SMF, entity, comprising: a processor, a memory;

the processor is used for reading the program in the memory and executing:

receiving a notification of an AMF entity; the AMF entity sends the notification after taking the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE if the request message sent by the UE contains the indication information for indicating the activation of the PDU session;

22. The SMF entity of claim 21, wherein the processor is further configured to:

23. The SMF entity of claim 22, wherein the processor is specifically configured to:

24. A User Equipment (UE), comprising: a processor, a memory;

the processor is used for reading the program in the memory and executing:

determining that PDU session needs to be activated;

sending a request message for requesting to activate the PDU session to an AMF entity, so that after receiving the request message, if the request message contains indication information for indicating to activate the PDU session, the AMF entity takes the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE, and notifies the SMF entity to restore the establishment of the user plane connection of the always-on PDU session.

25. The UE of claim 24, wherein the request message includes a list of PDU sessions that need to be activated.

26. The UE of claim 24, wherein the processor is further specific to:

27. An access and mobility management, AMF, entity, comprising:

a first determining module, configured to, if the request message includes indication information indicating that a PDU session is activated, use, by the AMF entity, an always-on PDU session recorded in context information of the UE as an always-on PDU session corresponding to the UE;

28. A session management function, SMF, entity, comprising:

a second receiving module, configured to receive a notification of the AMF entity; if the request message sent by the UE contains indication information for indicating activation of the PDU session, the AMF entity takes the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE and then sends the notification;

29. A User Equipment (UE), comprising:

a sending module, configured to send a request message for requesting activation of a PDU session to an AMF entity, so that after receiving the request message, if the request message includes indication information for indicating activation of the PDU session, the AMF entity uses the always-on PDU session recorded in the context information of the UE as the always-on PDU session corresponding to the UE, and notifies the SMF entity to restore establishment of user plane connection of the always-on PDU session.

30. A computer-readable medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 7, or the steps of the method according to any one of claims 8 to 10, or the steps of the method according to any one of claims 11 to 13.