CN109429364B

CN109429364B - Method and device for establishing session

Info

Publication number: CN109429364B
Application number: CN201710533748.1A
Authority: CN
Inventors: 李永翠; 李岩; 倪慧
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-07-03
Filing date: 2017-07-03
Publication date: 2020-06-02
Anticipated expiration: 2037-07-03
Also published as: CN109429364A; WO2019007226A1

Abstract

The application discloses a method and a device for establishing a session, wherein the method comprises the following steps: AN Access Network (AN) receives first downlink data from a User Plane Function (UPF), wherein the first downlink data comprises a first User Equipment (UE) network protocol IP address and first tunnel identification information; the AN sends a first message to AN access and mobility management function (AMF), wherein the first message comprises the first UE IP address and the first tunnel identification information; the AN receives a second message from the AMF, the second message including a context for establishing a first session, the first session being a session corresponding to the first UE IP address and the first tunnel identification information. According to the method for establishing the session, the first session corresponding to the first UE IP address and the first tunnel identification information can be established.

Description

Method and device for establishing session

Technical Field

The present application relates to the field of communications, and in particular, to a method and an apparatus for establishing a session in the field of wireless communications.

Background

The user plane model refers to a tunnel model between AN Access Network (AN) and a User Plane Function (UPF), where a tunnel refers to a communication path between the AN and the UPF.

The convergent user plane model is one of the user plane models. For the aggregated user plane model, one tunnel corresponds to multiple sessions, and the multiple sessions may belong to one terminal device or multiple terminal devices. The session is used to provide a Protocol Data Unit (PDU) connection service for a User Equipment (UE) and a Data Network (DN). When a plurality of sessions corresponding to the tunnel are deactivated, the AN cannot send new downlink data to the UE after receiving the new downlink data, so that the AN discards the new downlink data, and user experience is reduced.

Disclosure of Invention

In view of this, the present application provides a method and AN apparatus for establishing a session, which can solve the problem that the AN discards downlink data in the aggregated user plane model.

In a first aspect, a method for establishing a session is provided, including: the AN receives first downlink data from the UPF, wherein the first downlink data comprises a first UE network protocol (IP) address and first tunnel identification information; the AN sends a first message to AN access and mobility management function (AMF), wherein the first message comprises a first UE IP address and first tunnel identification information; the AN receives a second message from the AMF, the second message including a context for establishing a first session, the first session being a session corresponding to the first UE IP address and the first tunnel identification information.

According to the method for establishing the session, the AN sends the first UE IP address and the first tunnel identification information to the AMF and receives the context sent by the AMF and used for recovering the first session, so that the wireless connection between the UE and the AN corresponding to the first UE IP address and the first tunnel identification information can be recovered, and the AN is prevented from discarding the first downlink data.

Optionally, the method further comprises: the AN receives a third message from the AMF, wherein the third message comprises the identifier of the first session, the first corresponding relation between the IP address of the first UE and the first tunnel identifier information, and the third message also comprises the identifier of the second session, the second corresponding relation between the IP address of the second UE and the second tunnel identifier information.

When the AN receives downlink data corresponding to the second session, the session corresponding to the downlink data, that is, the second session, may be determined according to the second correspondence, so that a session context corresponding to the second session is obtained from a Session Management Function (SMF) through the AMF, thereby recovering a wireless connection between the UE and the AN corresponding to the IP address of the second UE and the identification information of the second tunnel, and avoiding the AN discarding the second downlink data.

Optionally, the method further comprises: the AN receives second downlink data from the UPF, wherein the second downlink data comprises a second UEIP address and second tunnel identification information; the AN sends a fourth message to the AMF, wherein the fourth message comprises the identification of the second session; the AN receives a fifth message from the AMF, the fifth message including a context for establishing the second session.

When the AN receives the second downlink data, the AN may determine the identifier of the second session according to the second UE IP address and the second tunnel identifier included in the second downlink data, and send the identifier of the second session to the AMF, so that the AMF may directly send the context for recovering the second session to the AN without determining the identifier of the second session according to the second UE IP address and the second tunnel identifier, thereby improving the response speed of the AMF and reducing the burden of the AMF.

Optionally, the method further comprises: and if the first UE is in AN idle state, the AN sends a paging message to the first UE, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

The AN may select a corresponding method for recovering the first session according to the current specific situation of the first UE, for example, when the first UE is in AN idle state, the paging method may be adopted to recover the first session, so as to avoid the AN discarding the first downlink data; when the first UE is in the connected state, the AN may directly obtain, through the AMF, a session context corresponding to the first session from the SMF corresponding to the first session, thereby recovering AN air interface connection between the AN corresponding to the first session and the first UE, and avoiding a reduction in user experience caused by discarding the first downlink data by the AN.

Optionally, the first tunnel identification information is at least one of a tunnel identification, tunnel information of AN side, and tunnel information of a UPF side.

Optionally, the method further comprises: and the AN sends first downlink data to the first UE through the first session, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

In a second aspect, a method for establishing a session is provided, including: the AMF receives a first message from the AN, wherein the first message comprises a first UE IP address and first tunnel identification information; the AMF sends a second message to the AN, wherein the second message comprises a context for establishing a first session, and the first session is a session corresponding to the IP address of the first UE and the first tunnel identification information.

According to the method for establishing the session, the AMF receives the first UE IP address and the first tunnel identification information from the AN and sends the context for recovering the first session to the AN, so that the wireless connection between the UE and the AN corresponding to the first UE IP address and the first tunnel identification information can be recovered, and the AN is prevented from discarding the first downlink data.

Optionally, the method further comprises: and if the first UE is in an idle state, the AMF sends a paging message to the first UE, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

The AMF may select a corresponding method for recovering the first session according to the current specific situation of the first UE, for example, when the first UE is in AN idle state, the paging method may be adopted to recover the first session, so as to avoid the AN discarding the first downlink data; when the first UE is in the connected state, the AMF may directly obtain, from the SMF corresponding to the first session, a session context corresponding to the first session, and send the session context to the AN, so that the AN recovers AN air interface connection between the AN corresponding to the first session and the first UE, thereby avoiding a reduction in user experience caused by discarding the first downlink data by the AN.

Optionally, the method further comprises: the AMF sends a third message to the AN, wherein the third message comprises the identifier of the first session, the first corresponding relation between the IP address of the first UE and the first tunnel identifier information, and the third message also comprises the identifier of the second session, the second corresponding relation between the IP address of the second UE and the second tunnel identifier information.

Optionally, the method further comprises: the AMF receives a fourth message from the AN, wherein the fourth message comprises the identification of the second session; the AMF sends a fifth message to the AN, the fifth message including a context for establishing the second session.

Optionally, the method further comprises: the AMF obtains a first corresponding relation among the first UE IP address, the first tunnel identification information and the identification of the first session from the SMF.

Optionally, the first tunnel identifier information is at least one of a tunnel identifier, tunnel information of AN side, and tunnel information of a UPF side.

In a third aspect, the present application provides a device for establishing a session, where the device may implement the functions performed by the AN in the method according to the first aspect, where the functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

In one possible design, the apparatus includes a processor and a communication interface, and the processor is configured to support the apparatus to perform the corresponding functions of the method. The communication interface is used to support communication between the device and other devices. The apparatus may also include a memory for coupling to the processor that retains program instructions and data necessary for the apparatus to function as described above.

In a fourth aspect, the present application provides an apparatus for transmitting data, where the apparatus can implement the functions performed by the AMF in the method according to the above aspects, and the functions can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

In a fifth aspect, the present application provides a computer storage medium for storing computer software instructions for the AN, which comprises 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 the AMF, which contains a program designed to perform the second aspect.

In a seventh aspect, the present application provides a communication chip having instructions stored therein, which when run on AN, cause the communication chip to control the AN to perform the method of the first aspect.

In an eighth aspect, the present application provides a communication chip having instructions stored therein, which when run on an AMF, cause the communication chip to control the AMF to perform the method of the second aspect.

In a ninth aspect, the present application provides a computer program product comprising: computer program code which, when executed by a communication unit and a processing unit of a communication apparatus, causes the communication apparatus to perform the method according to the first aspect.

In a tenth aspect, the present application provides a computer program product comprising: computer program code which, when executed by a communication unit and a processing unit of a communication apparatus, causes the communication apparatus to perform the method according to the second aspect.

Drawings

Fig. 1 is a schematic architecture diagram of a communication system to which the present application is applicable;

FIG. 2 is a schematic flow chart diagram of a method of establishing a session provided herein;

FIG. 3 is a schematic flow chart diagram of another method of establishing a session provided herein;

FIG. 4 is a schematic flow chart diagram of yet another method of establishing a session provided herein;

FIG. 5 is a schematic flow chart diagram of a method for obtaining a first correspondence provided herein;

FIG. 6 is a diagram of an information interaction for establishing a session provided herein;

FIG. 7 is a diagram of another information interaction for establishing a session provided herein;

FIG. 8 is a diagram of yet another information interaction for establishing a session provided herein;

FIG. 9 is a diagram of yet another information interaction for establishing a session provided herein;

FIG. 10 is a diagram of yet another information interaction for establishing a session provided herein;

FIG. 11 is a diagram of yet another information interaction for establishing a session provided herein;

fig. 12 is a schematic structural diagram of a possible AN provided in the present application;

fig. 13 is a schematic structural diagram of another possible AN provided in the present application;

FIG. 14 is a schematic diagram of one possible AMF configuration provided herein;

fig. 15 is a schematic diagram of another possible AMF structure provided by the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

Fig. 1 shows a communication system to which the present application is applicable. The communication system includes UE110, UE120, AN130, UPF140, AMF150, SMF160, and DN 170. UE110 and UE120 each communicate with AN130 via a wireless network, and AN130, UPF140, AMF150, SMF160, and DN170 may communicate via corresponding core network interfaces (connections shown in fig. 1). All the network elements are entity devices. In this application, AN may also be referred to as AN apparatus, SMF may also be referred to as SMF apparatus, SMF network element, or SMF entity, and AMF may also be referred to as AMF apparatus, AMF network element, or AMF entity.

The communication connection between the AN130 and the UPF140 may be referred to as a tunnel. One tunnel may carry one or more sessions. A tunnel carrying only one session corresponds to a user plane model of session granularity. The tunnels carrying a plurality of sessions correspond to an aggregated user plane model. The multiple sessions may belong to the same UE or may belong to different UEs. Optionally, one UE may access the data network through the session-granular tunnel and the aggregated tunnel at the same time.

As shown in fig. 1, tunnel 1 carries three sessions, which are session 1, session 2 and session 3, respectively, where session 1 and session 2 belong to UE110 and session 3 belongs to UE 120. Since tunnel 1 carries multiple sessions, the user plane model between AN130 and UPF140 is referred to as AN aggregated user plane model.

In this application, a UE may be referred to as a terminal device, 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. The UE may be a cellular phone, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, and a user equipment in a 5th-generation, 5G communication system.

The AN may be a Base Transceiver Station (BTS) in a Code Division Multiple Access (CDMA) system, a base station (node B, NB) in a Wideband Code Division Multiple Access (WCDMA) system, AN evolved node B (eNB) in a Long Term Evolution (LTE) system, or a base station (gNB) in a 5G communication system, where the base station is merely AN example, and the AN may also be a relay station, AN access point, a vehicle-mounted device, a wearable device, and other types of devices.

The AMF may be responsible for UE attachment, mobility management, tracking area update procedures, etc.

The SMF entity may be responsible for session management of the UE, selection, reselection of UPF, IP address allocation, quality of service (QoS), and establishment, modification, and release of sessions. In the 5G system, the SMF entity and the AMF entity are connected through an N11 interface. The SMF entity is connected with the UPF through an N4 interface. The AMF entity is connected with the AN through AN N2 interface. In the following description, a message transmitted through the N11 interface may be referred to as an N11 message. The messages transmitted over the N4 interface may be referred to as N4 messages. The messages transmitted over the N2 interface may be referred to as N2 messages. In addition, these messages may also have other names in different scenarios, and the present application is not limited thereto.

The UPF is connected to the DN for enabling data transmission of the service in a service area of the UPF.

The above-mentioned communication system to which the present application is applied is only AN example, and the communication system to which the present application is applied is not limited thereto, and for example, the number of ANs, AMFs, SMFs, UPFs, DNs, and UEs included in the communication system may also be other numbers. The AN, AMF, SMF, DN and UE may have other names, and the use of AN, AMF, SMF, UPF, DN and UE in this application is not meant to limit the scope of protection of this application.

To facilitate an understanding of the present application, a detailed description of concepts related to the present application will be provided.

The AMF is mainly responsible for mobility management of the UE, such as location update, network registration, handover, and the like. In the scenario shown in fig. 1, after a session is established between a UE and a DN, the context information of the UE stored in the AMF150 mainly includes: UE identification, session identification and SMF identification.

The SMF is mainly responsible for session management of the UE, such as session establishment, modification, and release, and the specific functions include allocating an IP address to a user, selecting a UPF providing a message forwarding function, and the like. In the scenario shown in fig. 1, after a session is established between a UE and a DN, the context information of the session stored on the SMF160 mainly includes: a session identifier, and quality of service (QoS) parameters corresponding to the session. For example, the QoS parameters include: allocation and Retention Priority (ARP), session-aggregate maximum bit rate (session-AMBR) for session granularity, UE-aggregate maximum bit rate (UE-AMBR) for UE granularity. Alternatively, a session may include multiple traffic flows, each of which may have different QoS parameters.

The AN is primarily responsible for the equipment providing wireless access for the UE. In the scenario shown in fig. 1, after a session is established between the UE and the DN, the context saved in the AN130 mainly includes the following corresponding to the session: radio connection information (e.g., Data Radio Bearer (DRB) identity) between the UE and the AN, tunnel connection information (e.g., UPF side tunnel identity) between the AN and the UP, IP address of the UE, QoS parameter.

The aggregated user plane model may contain multiple sessions. In order to compare with the session-granularity user plane model, before introducing the method for establishing a session provided by the present application, a method for managing the session-granularity user plane model is described with reference to fig. 2.

When a tunnel carries only one session, the user plane model is referred to as a session-granular user plane model. For the user plane model of session granularity, when a session is deactivated (e.g., the UE enters AN idle state, or the UE is in a connected state but the session of the UE is deactivated), the tunnel between the AN and the UPF is disconnected. When the UPF receives the downlink data of the session, the communication system needs to reestablish (i.e., recover) the session corresponding to the downlink data, and the flow of recovering the session is shown in fig. 2. The method for recovering the session shown in fig. 2 includes the following steps:

s201, after receiving the downlink data, the UPF sends a data notification (data notification) to the SMF to notify the SMF that there is downlink data to be sent.

S202, after receiving the data notification, the SMF sends an N11 message to the AMF, wherein the N11 message carries the session identifier, the QoS parameter and the UPF side tunnel information. For example, the UPF side tunnel information is the IP address of the UPF and/or the UPF side tunnel endpoint identification.

S203, the AMF saves the current state of the UE, and the AMF determines whether to execute S204 according to the state of the UE. When the UE is in the idle state, the AMF sends a paging message to the AN, and the AN triggers a paging procedure according to the paging message and performs step S204. When the UE is in the connected state, the AMF directly performs S205 without paging the UE.

S204, the UE receives the paging message and sends a service request to the AMF through the AN. The service request is a response message to the paging message.

S205, the AMF sends a context establishment request to the AN, where the context establishment request carries the session identifier, the QoS parameter, and the UPF side tunnel information in S202.

S206, the AN triggers the wireless connection establishment process between the UE and the AN according to the received context establishment request.

S207, the AN sends a context establishment response of the UE to the AMF, and the context establishment response carries the AN side tunnel information. For example, the AN-side tunnel information is AN IP address and/or AN-side tunnel endpoint identification.

S208, AMF sends N11 message to SMF, the N11 message carries the session identification and AN side tunnel information.

S209, the SMF initiates a user plane path modification process to the UPF. For example, the SMF sends a user plane path modification request carrying the session identifier and the AN side tunnel information to the UPF; the UPF returns a user plane path modification response.

At this time, the session between the UE and the DN is successfully recovered, and the UPF sends downlink data corresponding to the session to the UE through the user plane tunnel between the AN and the UPF and the DRB between the UE and the AN.

In this application, the interface between the AMF and the SMF is referred to as an N11 interface, so the message interaction between the two can be simply referred to as an N11 message. The invention is not limited to specific message names.

For AN aggregated user plane model, such as the user plane model shown in fig. 1, deactivation of a session does not affect the tunnel connection between AN and UP. For example, session 1 is deactivated, but tunnel 1 is not disconnected. When the UPF receives the downlink data corresponding to the session 1, the UPF directly sends the downlink data to the AN through the user plane tunnel between the UPF and the AN. Since the AN has emptied all information of the session 1 when the session 1 is deactivated, including DRB information between the AN and the UE, when the AN receives the downlink data, it is not possible to determine which DRB the downlink data corresponds to, and thus the downlink data cannot be sent to the UE, which results in that the AN discards the downlink data, and user experience is reduced.

The cause of the above-described problem will be analyzed in detail with reference to fig. 1.

For a session of a UE, when there is a user plane connection between the UE and AN, AN and UP, i.e. data of the UE can be transmitted, the session is in AN active state (activation). When there is no user plane connection between the UE and the AN, but the context of the session is stored on the SMF, such as the IP address of the UE, the session identifier, etc., the session is in a deactivated state (deactivation). For a session in the deactivated state, the information for that session saved on the AN will be deleted altogether.

For example, the context information saved on the AN130 is shown in table 1 below:

session 1	Wireless connection information 1	Tunnel connection information 1	UE IP1	QoS parameter 1
					Session 1	Wireless connection information 2	Tunnel connection information 1	UE IP1	QoS parameter 2
Session 2	Wireless connection information 3	Tunnel connection information 1	UE IP2	QoS parameter 1
					Session 3	Wireless connection information 4	Tunnel connection information 1	UE IP3	QoS parameter 1

TABLE 1

Take session 1 as an example. Before the session 1 is deactivated, if the downlink data reaches the AN through the tunnel 1 corresponding to the tunnel connection information 1 and the downlink data carries the QoS parameter 1, according to table 1, the AN may determine that the downlink data is the downlink data of the session 1 according to the tunnel connection information 1 and the QoS parameter 1 in the context information, and send the downlink data to the UE110 through the DRB1 corresponding to the wireless connection information 1.

In the scenario shown in fig. 1, when session 1 is deactivated, the related information of session 1 on AN130 is completely deleted, and the context information stored by AN130 becomes as shown in table 2:

session 2	Wireless connection information 3	Tunnel connection information 1	UE IP2	QoS parameter 1
					Session 3	Wireless connection information 4	Tunnel connection information 1	UE IP3	QoS parameter 1

TABLE 2

When the session 1 is deactivated, for the above case, when the downlink data of the session 1 arrives, the UPF140 sends the downlink data to the AN130 through the tunnel 1, but since the AN130 does not have the wireless connection information corresponding to the downlink data, the AN130 cannot send the downlink data to the UE. Then the downstream data will be discarded resulting in a degraded user experience.

The application provides a solution to the above problems: the AMF maintains AN association between the UE IP address, tunnel identification information (such as tunnel identification, tunnel information on AN side, and tunnel information on a UPF side) and the UE identification, session identification, and SMF identification. For example, in the scenario shown in fig. 1, the context of the UE saved on the AMF150 is:

UE110	session 1	SMF160	UE IP1	Tunnel identification information 1
					UE110	Session 2	SMF160	UE IP2	Tunnel identification information 1
UE120	Session 3	SMF160	UE IP3	Tunnel identification information 1

Along the lines of the above solution, fig. 3 shows a schematic flow chart of a method 300 for establishing a session provided by the present application. The method 300 includes:

s310, the AN receives first downlink data from the UPF, wherein the first downlink data comprises a first UE IP address and first tunnel identification information.

S320, the AN sends a first message to the AMF, wherein the first message comprises the first UE IP address and the first tunnel identification information.

S330, the AN receives a second message from the AMF, wherein the second message comprises a context for establishing a first session, and the first session is a session corresponding to the IP address of the first UE and the identification information of the first tunnel. And the AN recovers the wireless connection between the UE and the AN according to the received second message, so that the AN can send the first downlink data to the UE.

In S310, the first downlink data is any one of the downlink data sent by the UPF, and after receiving the first downlink data, the AN analyzes the first UE IP address and the first tunnel identifier information from the first downlink data.

For example, the first tunnel identification information is AN identification (i.e., a tunnel identification) of a tunnel transmitting the first downlink data, or the first tunnel identification information is tunnel information of the tunnel transmitting the first downlink data on the AN side, or the first tunnel identification information is tunnel information of the tunnel transmitting the first downlink data on the UPF side, or the first tunnel identification information includes at least two of the tunnel identification, the tunnel information of the AN side, and the tunnel information of the UPF side. For example, the AN-side tunnel information includes AN IP address and/or AN-side tunnel endpoint identification. The UP side tunnel information includes a UP IP address and/or an UP side tunnel endpoint identification. The foregoing examples are merely examples, and the first tunnel identification information is used to identify a tunnel for transmitting the first downlink data, and the specific content of the first tunnel identification information is not limited in this application.

After receiving the first downlink data, the AN cannot transmit the first downlink data to the UE because the AN does not have the radio connection information corresponding to the first downlink data. According to the method described in the present application, the AN sends a first message to the AMF, where the first message includes a first UE IP address and first tunnel identification information, so that the AMF determines a session corresponding to the first UE IP address and the first tunnel identification information. Further, the UE IP address may also be referred to simply as UE IP.

The first message may be a notification message, and the notification message is used to notify the AMF that the AN has received downlink data including the first UE IP address and the first tunnel identification information. Alternatively, the first message may also be a request message, where the request message is used to request to acquire information of a session corresponding to the first UE IP address and the first tunnel identification information. After receiving the first message, the AMF may send information of the first session (i.e., the session corresponding to the IP address of the first UE and the first tunnel identification information) to the AN through a third message, or may send information of part or all of the session of the first UE (i.e., the UE to which the first session belongs) to the AN.

For example, the information of a part or all of the sessions of the UE to which the first session belongs includes: and the corresponding relation among the UE IP address, the tunnel identification information and the session identification. For example, the information of the session of the UE includes a first corresponding relationship and a second corresponding relationship, where the first corresponding relationship includes a first corresponding relationship among a first UE IP address, first tunnel identification information, and an identification of the first session; the second correspondence includes a second correspondence among the second UE IP address, the second tunnel identification information, and the identification of the second session. The first session and the second session may be all sessions of the UE or only a part of sessions of the UE. It should be noted that the first corresponding relationship or the second corresponding relationship may further include: and the corresponding relation between the UE identification, the SMF identification and the parameters. Wherein the SMF identification is used for identifying the SMF.

In addition, the AN receives a second message from the AMF after transmitting the first message to the AMF. The second message is a message carrying a context for establishing the first session. The present application does not limit the specific names of the first message and the second message. By the method, when the AN receives the downlink data, the context information of the first session to which the downlink data belongs can be obtained from the AMF, so that the wireless connection of the first session between the UE and the AN is recovered, the phenomenon that the AN discards the downlink data because the AN does not have the wireless connection corresponding to the downlink data is avoided, and the user experience is reduced.

Hereinafter, the technical solution of the present application will be described by taking the first message as a notification message and a request message as examples.

In the case of the situation 1 that is described,

and when the first message is a notification message, the AMF determines the information of the first session corresponding to the IP address of the first UE and the first tunnel identification information according to the first corresponding relation. For example, the information of the first session may be an identification of the first session. For example, the AMF may store the first corresponding relationship in a table form, and determine the information of the first session by querying the table. In addition, the AMF may also determine the information of the first session in other manners, and the application is not limited to a specific form of the first corresponding relationship and a specific manner in which the AMF determines the first session.

In addition, the first correspondence may further include a UE to which the first session belongs (i.e., the first UE) and an SMF related to the first session. The AMF may determine, according to the first UE IP address and the first tunnel identification information carried in the first message and the first corresponding relationship, a UE (i.e., a first UE) to which the first session belongs, and perform a recovery procedure of the first session according to a state of the first UE.

(1) When the first UE is in an idle state, the AMF initiates a paging procedure to page the first UE, and the specific paging procedure may refer to a procedure for paging the UE in the prior art, which is not described herein again. The IDLE state may also be referred to as a connection management IDLE (CM-IDLE) state.

After the first UE is paged, the AMF sends a session context acquisition request to the first SMF (i.e., the SMF managing the first session), where the session context acquisition request carries an identifier of the first session. Subsequently, the AMF receives a session context acquisition response from the first SMF, the session context acquisition response carrying a context required for establishing the first session, e.g., QoS parameters of the first session. The AMF sends a session context establishment request to the AN, wherein the context establishment request carries a context required by establishing the first session. And the AN establishes AN air interface connection with the first UE according to the context and sends a session context establishment response to the AMF.

(2) When the first UE is in a connected (connected) state, the AMF may directly send a session context acquisition request to an SMF corresponding to the first session (i.e., the first SMF), and subsequent steps are the same as the processing steps of the AMF in case (1), and are not described herein again. The above connection state may also be referred to as a connection management CONNECTED (CM-CONNECTED).

It should be noted that, after receiving the notification message, the AMF may further send the saved correspondence (including but not limited to the first correspondence) of the first UE to the AN. In this way, when the AN receives downlink data (e.g., second downlink data) corresponding to another session of the first UE, the AN may directly determine the second session corresponding to the second downlink data according to the correspondence, so that the AN obtains the context of the second session from the SMF corresponding to the second session through the AMF, and further recovers the wireless connection between the UE corresponding to the second session and the AN more quickly, so that the AN sends the second downlink data to the UE.

In the case of 2, the first and second cases,

and when the first message is a request message, the AMF determines the session corresponding to the IP address of the first UE and the first tunnel identification information according to the first corresponding relation to determine the information of the first session. For example, the information of the first session may be an identification of the first session. For example, the AMF may store the first corresponding relationship in a table form, and determine the information of the first session and the first UE by querying the table. In addition, the AMF may also determine the information of the first session in other manners, and the application is not limited to a specific form of the first corresponding relationship and a specific manner in which the AMF determines the first session.

And then the AMF sends a third message to the AN, wherein the third message carries the information of part or all of the session corresponding to the first UE. For example, the third message may carry the first correspondence and the second correspondence. The first corresponding relation comprises a first corresponding relation among the IP address of the first UE, the first tunnel identification information and the identification of the first session; the second correspondence includes a second correspondence among the second UE IP address, the second tunnel identification information, and the identification of the second session. The first and second correspondences may be information of all sessions of the first UE (for example, the first UE includes only the first and second sessions), or the first and second correspondences are information of only partial sessions of the first UE (for example, the first UE includes at least 3 sessions). In this way, when the AN receives downlink data (e.g., second downlink data) corresponding to another session of the first UE, the AN may directly determine the second session corresponding to the second downlink data according to the correspondence, so that the AN obtains the context of the second session from the SMF corresponding to the second session through the AMF, and further recovers the wireless connection between the UE corresponding to the second session and the AN more quickly, so that the AN sends the second downlink data to the UE.

In addition, the AMF also stores the corresponding relationship between the UE id, the SMF id and the session id, so that the third message may carry the corresponding relationship between the UE IP, the tunnel id, the session id, the UE id and the SMF id.

And the AN judges whether the first UE has the session in the activated state according to the corresponding relation in the third message, thereby judging the state of the UE. For the session in the activated state, the AN stores the air interface connection information corresponding to the session. Wherein the air interface connection information of the session refers to a wireless connection between the UE and the AN. Therefore, when the session information of the first UE stored by the AN does not include the air interface connection information of the session, the AN determines that the UE is in the idle state. For example, if the first UE has a session in AN active state, the AN determines that the first UE is in a connected state; and if the first UE does not have the session in the activated state, the AN judges that the UE is in AN idle state. And then, the AN carries out a session recovery process according to the state of the first UE. As follows:

(3) when the first UE is in the idle state, the AN initiates a paging procedure to page the first UE, and the specific paging procedure may refer to a procedure for paging the UE in the prior art, which is not described herein again.

After the first UE is paged, the AN sends a session context acquisition request to the first SMF through the AMF, wherein the session context acquisition request carries AN identifier of a first session; subsequently, the AN receives a session context acquisition response from the first SMF through the AMF, where the session context acquisition response carries a context required for establishing the first session, for example, a QoS parameter of the first session; and the AN establishes air interface connection with the first UE according to the context.

(4) When the first UE is in the connected state, the AN does not need to page the UE, determines the session corresponding to the first downlink data according to the stored first corresponding relationship, and sends a session context acquisition request to the first SMF corresponding to the first session through the AMF, and subsequent steps are the same as the processing steps of the AN in case (3), and are not described herein again.

After the first session is resumed, the AN may send the first downlink data to the first UE.

It should be noted that, in the present application, "when …", "if" and "if" all refer to that the UE or the AN performs corresponding processing under a certain objective condition, and do not limit the time, and do not require the UE or the AN to perform the action of determining the time, and do not mean that there are other limitations.

Optionally, when the first message is a notification message, the third message may be a response message of the notification message; when the first message is a request message, the third message may be a response message to the request message. When the first message is a notification message, the AMF may not send a response message to the notification message.

In addition, the names of the same messages can be called by various names, and the names of the messages in the application are only used for illustration and should not be understood as limitations of the technical solution of the application, and the names of the messages should be subject to the practical function.

In summary, in the method 300 for establishing a session provided by the present application, AN may recover a first session corresponding to a first UE IP address and first tunnel identification information by sending the first UE IP address and the first tunnel identification information to AN AMF and receiving a context for recovering the first session sent by the AMF.

Optionally, the method 300 further comprises:

s340, the AN receives a third message from the AMF, where the third message includes the identifier of the first session, the first correspondence between the first UE IP address and the first tunnel identifier information, and the third message further includes the identifier of the second session, the second correspondence between the second UE IP address and the second tunnel identifier information.

In the second correspondence relationship, the second session is any one of all sessions corresponding to the first UE, which is different from the first session.

Optionally, the method 300 further comprises:

s350, the AN receives second downlink data from the UPF, where the second downlink data includes the second UEIP address and the second tunnel identification information.

And S360, the AN determines a session (i.e. a second session) corresponding to second downlink data according to the saved session information of the first UE, the IP address of the second UE and the second tunnel identification information, and sends a fourth message to the AMF, wherein the fourth message comprises AN identification of the second session. And the AMF sends a context acquisition request to the SMF corresponding to the second session identifier according to the corresponding relation between the session identifier and the SMF identifier so as to acquire the context corresponding to the second session.

Optionally, when the correspondence stored by the AN includes the SMF identifier, the AN directly sends a session context acquisition request to the SMF corresponding to the second session through the AMF, so as to acquire the context corresponding to the second session.

And the AMF receives a session context acquisition response returned by the SMF, wherein the session context acquisition response carries a context of a second session, such as a QoS parameter corresponding to the second session.

S370, the AN receives a fifth message from the AMF, the fifth message including a context for establishing the second session.

The second downlink data is a session different from the UE corresponding to the first downlink data, after receiving the second downlink data, the AN determines the first UE according to the second downlink data including the second UE IP address and the second tunnel identification information, and determines a session (i.e., a second session) corresponding to the second UE IP address and the second tunnel identification information according to the correspondence received from the AMF, and then performs a recovery procedure of the second session. Therefore, how to realize session management of session granularity (namely, session activation) when a communication system adopts a convergent user plane model is solved, for example, when a deactivated session has new downlink data to be transmitted, the UPF directly sends the new downlink data to the AN, and after the AN receives the new downlink data, the AN determines a new session corresponding to the downlink according to the stored session information of the UE, so that the AMF acquires a session context corresponding to the session from the SMF, thereby recovering the wireless connection between the UE corresponding to the session and the AN, and the AN can send the new downlink data to the UE. That is to say, the AN may send the new downlink data to the UE according to the method for establishing a session provided in the present application, thereby avoiding that the AN discards the new downlink data because the AN cannot send the new downlink data to the UE, and improving user experience.

The fourth message is a message carrying an identifier of the second session, the fifth message is a message carrying a context for reestablishing the second session, and the names of the fourth message and the fifth message are not limited in the present application.

Fig. 4 shows another schematic flow chart of a method 400 for establishing a session provided by the present application. The method 400 includes:

s410, the AMF receives a first message from the AN, wherein the first message comprises a first UE IP address and first tunnel identification information.

S420, the AMF sends a second message to the AN, where the second message includes a context for establishing a first session, and the first session is a session corresponding to the first UE IP address and the first tunnel identification information.

As is clear to the skilled person: in the method 400, the AMF and the AN may both be identical to the AMF and the AN in the method 300, and actions of the AMF and the AN correspond to actions of the AMF and the AN in the method 300, and in addition, the first message and the second message are also identical to the first message and the second message in the method 300, and are not described herein again for brevity.

Therefore, in the method 400 for establishing a session provided by the present application, the AMF receives the first UE IP address and the first tunnel identification information from the AN, and sends a context for establishing the first session to the AN, so that the first session corresponding to the first UE IP address and the first tunnel identification information can be established.

Optionally, the method 400 further comprises:

s430, if the first UE is in idle state, the AMF sends paging message to the AN to page the first UE. The first UE is the UE corresponding to the first UE IP address and the first tunnel identification information.

Optionally, the method 400 further comprises:

s440, the AMF sends a third message to the AN, where the third message includes the identifier of the first session, the first correspondence between the first UE IP address and the first tunnel identifier information, and the third message further includes the identifier of the second session, the second correspondence between the second UE IP address and the second tunnel identifier information.

The third message may carry only the first corresponding relationship, or may carry the first corresponding relationship and a second corresponding relationship, where in the second corresponding relationship, the second session is any one of all sessions corresponding to the first UE, which is different from the first session.

Therefore, how to realize session management of session granularity (namely, session activation) when a communication system adopts a convergent user plane model is solved, for example, when a deactivated session has new downlink data to be transmitted, the UPF directly transmits the new downlink data to the AN, the AN determines a new session corresponding to the downlink according to the stored session information of the UE after receiving the new downlink data, and then obtains a session context corresponding to the session from the SMF through the AMF, so that the wireless connection between the UE corresponding to the session and the AN is recovered, and the AN can transmit the new downlink data to the UE. That is to say, the AN may send the new downlink data to the UE according to the method for establishing a session provided in the present application, thereby avoiding that the AN discards the new downlink data because the AN cannot send the new downlink data to the UE, and improving user experience.

Optionally, the method 400 further comprises:

s450, the AMF receives a fourth message from the AN, the fourth message including AN identification of the second session.

S460, the AMF sends a fifth message to the AN, where the fifth message includes a context for recovering the second session.

In the method 400, the third message, the fourth message, and the fifth message are the same as the third message, the fourth message, and the fifth message in the method 300, and are not repeated for brevity.

Optionally, the method 400 further comprises:

s470, the AMF obtains the first corresponding relationship between the first UE IP address, the first tunnel identification information, and the identification of the first session from the SMF.

Fig. 5 is a schematic flow chart illustrating a method for acquiring the first corresponding relationship by the AMF according to the present application. For example, the AMF acquires the first correspondence in the session establishment process. The method 500 includes:

s501, the UE sends a session setup request (session setup request) to the AMF through the AN to request to setup a session. The session establishment request carries a session identification (i.e., an identification of the first session) and a Data Network Name (DNN).

S502, the AMF selects the SMF providing the session management service for the UE, and stores the corresponding relation between the session identification and the SMF identification.

S503, the AMF sends an N11 message to the SMF. The N11 message may be a session management request (SM request) carrying a session establishment request. The session establishment request carries a session identifier and a DNN.

S504, after receiving the N11 message, the SMF judges whether a user plane path exists between the AN and the UPF. And when no user plane path exists between the AN and the UPF, initiating a user plane path establishment process. For example, the SMF allocates a tunnel identifier, allocates an IP address to the UE, and sends an N4session establishment request (N4session setup request) to the UPF, where the N4session establishment request carries the session identifier, the DNN, and the tunnel identifier. Optionally, when the SMF is preconfigured with information of the aggregated user plane model, the N4session establishment request may also carry AN-side tunnel information. The SMF receives an N4session establishment response from the UPF, wherein the N4session establishment response carries the UP side tunnel information and the tunnel identification. The AN side tunnel information comprises AN AN IP address and/or AN AN side tunnel endpoint identification. The UP side tunnel information includes a UP IP address and/or an UP side tunnel endpoint identification.

S505, the SMF sends an N11 message to the AMF, where the N11 message carries a first correspondence, that is, a correspondence between the first tunnel identification information, the first UE IP address, and the identification of the first session. The first tunnel identification information is at least one of UP side tunnel information, AN side tunnel information and a tunnel identification. The N11 message may also carry other information, such as QoS parameters.

S506, the AMF stores the first corresponding relation.

At this time, the information stored in the AMF includes a corresponding relationship between the UE identifier, the SMF identifier corresponding to the first session, the first tunnel identifier information, the first UE IP address, and the identifier of the first session. The UE identification is used for uniquely identifying an end user, and the AMF stores the UE identification in the process of registering the UE to the data network.

S507, the AMF sends AN N2 message to the AN, wherein the N2 message carries the session identification, the UE IP and the QoS parameters, and the N2 message is used for requesting the AN to establish the radio bearer.

S508, the AN initiates a radio bearer establishment procedure.

S509, the AN sends AN N2 message to the AMF, the N2 message indicating that the radio bearer has been established.

The above embodiment of obtaining the first corresponding relationship by the AMF is merely an example, and the application is not limited thereto, and for example, the first corresponding relationship may be configured in the AMF in a pre-configuration manner.

Therefore, when receiving the first message including the first UE IP address and the first tunnel identification information sent by the AN, the AMF may determine the first session corresponding to the first UE IP address and the first tunnel identification information according to the first corresponding relationship, and further reestablish the first session.

Optionally, the first tunnel identification information is at least one of AN identification (i.e., a tunnel identification) of a tunnel through which the first downlink data is transmitted, tunnel information of AN side, and tunnel information of a UPF side. The foregoing examples are merely examples, and the first tunnel identification information is used to identify a tunnel for transmitting the first downlink data, and the specific content of the first tunnel identification information is not limited in this application.

When the UE establishes the second session, the AMF updates the stored information and adds session information related to the second session. For example, the information stored in the AMF includes, after updating:

a correspondence between the UE identity, the SMF identity corresponding to the first session, the first tunnel identity information, the first UE IP address, the identity of the first session, and,

a UE identity, an SMF identity corresponding to the second session, tunnel identity information (e.g., second tunnel identity information) corresponding to the second session, a UE IP address (e.g., second UE IP address) corresponding to the second session, and an identity of the second session.

In order to more clearly describe the method for establishing a session provided by the present application, an information interaction diagram for establishing a session provided by the present application will be introduced below in conjunction with the above content.

As shown in fig. 6, in this method, the AMF stores the correspondence, and when the UE needs to be paged, the AMF triggers the paging procedure. The method comprises the following steps:

s601, the AN receives downlink data from the UPF, where the downlink data includes a UE IP address and tunnel identification information (i.e., session information).

S602, since the AN does not store the wireless connection information corresponding to the downlink data, the AN sends a notification message to the AMF, where the notification message carries the session information in S601.

S603, the AMF determines the session, the UE and the SMF corresponding to the received session information according to the stored correspondence (i.e., UE identity-session information-session identity-SMF identity).

Subsequently, the AMF performs the following different steps according to different states of the UE corresponding to the session information.

When the UE is in the idle state (the AMF may determine the state of the UE according to the stored UE context, which is the prior art and is not described herein), the AMF triggers the paging procedure, and executes S604 to S606.

S604, AMF sends paging message to AN, the paging message carries paging identification, the paging identification is used to identify UE.

Optionally, the AMF may send all or part of the corresponding relationship related to the UE to the AN, so that when the AN receives downlink data of another session of the UE from the UPF again, the session corresponding to the downlink data may be determined directly according to the corresponding relationship stored in the AN, so as to obtain a session context corresponding to the session, and there is no need to send a notification message to the AMF, and there is no need to determine the session corresponding to the downlink data by the AMF, thereby reducing a burden of the AMF. For example, the AMF may send all or part of the correspondence relationship related to the UE to the AN through the paging message, or may send all or part of the correspondence relationship related to the UE to the AN through a message other than the paging message.

S605, the AN pages the UE according to the received paging message.

S606, the paged UE initiates a service request procedure to recover the session. For example, the service request flow may include S607 to S611.

When the UE is in the connected state (the AMF may determine the state of the UE according to the stored UE context, which is the prior art and is not described herein), the AMF triggers the context establishment procedure, for example, executes S607.

S607, the AMF sends a session context obtaining request to the SMF corresponding to the session information, where the session context obtaining request carries the session identifier.

S608, the SMF sends a session context acquisition response to the AMF, where the session context acquisition response carries a session context corresponding to the session identifier, and the session context may be, for example, QoS information of the session.

S609, the AMF forwards the session context setup request to the AN, where the session context setup request carries the session context in S608.

S610, the AN triggers a wireless connection establishment process between the UE and the AN.

It should be noted that, after the SMF forwards the determined session context to the AN through the AMF, the AN establishes a DRB between the AN and the UE according to the received session context. Thus, the AMF may not need to understand the session context sent by the SMF.

S611, the AN sends a session context setup response to the AMF.

Fig. 7 shows another information interaction diagram for establishing a session provided by the present application. In the method shown in fig. 7, the AMF passes the correspondence to the AN, and the AN saves the correspondence. When the UE needs to be paged, the AN triggers a paging process. The method comprises the following steps:

s701, the AN receives downlink data from the UPF, and acquires the UE IP address and the tunnel identification information (i.e., session information) from the downlink data.

S702, since the AN does not store the wireless connection information corresponding to the downlink data, the AN sends a request message to the AMF, where the request message carries the session information in S701. The request message is used for requesting the AMF to send the corresponding relationship of the UE corresponding to the session information to the AN.

S703, the AMF determines the session, the UE, and the SMF corresponding to the received session information according to the stored corresponding relationship (i.e., UE identifier-session information-session identifier-SMF identifier), and sends a response message to the AN, where the response message carries the corresponding relationship, so that the AN stores the corresponding relationship and establishes the session corresponding to the downlink data in S701 according to the corresponding relationship.

Optionally, the response message in S703 may carry other corresponding relationships (e.g., all or part of the corresponding relationships of the UE) related to the UE in S703, so that when the AN receives downlink data belonging to other sessions of the UE from the UPF again, the session corresponding to the downlink data may be determined directly according to the corresponding relationships stored in the AN, and the session context corresponding to the session is obtained.

Then, the AN performs the following different steps according to different states of the UE corresponding to the session information. It should be noted that, the AN determines the state of the UE according to the context information of the UE stored in the AN, and one implementation manner is: when the context information of the UE stored in the AN has wireless connection information, the AN judges that the UE is in a connected state; otherwise, the AN judges that the UE is in AN idle state.

When the UE is in AN idle state (the AN may determine the state of the UE according to the context information of the UE stored in the AN), the AN triggers a paging procedure, and performs S704.

S704, the AN pages the UE.

S705, the paged UE initiates a service request procedure to resume the session. For example, the service request flow may include S706 to S708.

When the UE is in the connected state (the AN may determine the state of the UE according to the context information of the UE stored in the AN), the AN triggers the context establishment procedure, and executes S706.

S706, the AN sends a session context acquisition request to the SMF corresponding to the session information through the AMF, wherein the session context acquisition request carries a session identifier.

S707, the SMF sends a session context obtaining response to the AN through the AMF, where the session context obtaining response carries a context for establishing a session, and the context may be, for example, QoS information of the session.

S708, the AN triggers a radio bearer setup procedure between the UE and the AN.

S709, the AN sends a session context setup response to the SMF.

Fig. 8 is a diagram illustrating still another information interaction for establishing a session provided by the present application. In the method shown in fig. 8, the AMF passes the correspondence to the AN, and the AN saves the correspondence. When the UE needs to be paged, the paging procedure is triggered by the AMF. The method comprises the following steps:

s801, the AN receives downlink data from the UPF, and acquires the UE IP address and the tunnel identification information (i.e., session information) from the downlink data. If the AN stores the wireless connection information of the UE corresponding to the session information, the AN determines that the UE is in a connected state, and at this time, the AN may directly ask for a session context from the SMF through the AMF, so as to recover the session corresponding to the received downlink data.

S802, if the AN does not have the wireless connection information of the UE corresponding to the session information, the AN determines that the UE is in AN idle state, and at this time, because the AN cannot determine which session the session information belongs to, and cannot determine the wireless connection information corresponding to the downlink data, the AN sends a request message to the AMF, where the request message carries the session information in S801. The request message is used for notifying the AMF that downlink data are sent to the AN, and is used for requesting the AMF to send all or part of the corresponding relation of the UE corresponding to the session information to the AN.

S801 to S802 may be replaced by the following steps: s801', the SMF receives the session activating request sent by the UPF and carries the session identification. The session activating request is used for triggering the SMF to recover the connection corresponding to the session. S802', SMF sends N11 message to AMF, carrying session information. The session information includes QoS parameters corresponding to the session, tunnel information of the UPF, and the like. At this time, if the AMF determines that the UE is in AN idle state, the AMF pages the UE and sends all or part of the correspondence of the UE to the AN. If the AMF judges that the UE is in the connection state, the AMF sends the session information to the AN, and triggers the AN to recover the DRB connection between the AN and the UE according to the session information. That is, the AMF sends all or part of the correspondence of the UE to the AN, which may be triggered by a request message sent by the AN in AN aggregated user plane model scenario, or may be triggered by AN N11 message sent by the SMF in a user plane model of session granularity.

S803, the AMF determines the session, the UE and the SMF corresponding to the received session information according to the session information received from the AN and the stored correspondence (i.e., UE identity-session information-session identity-SMF identity). In addition, the AMF transmits the correspondence relationship of the UE to the AN through a paging message, or other messages except the paging message.

S804, the AMF may trigger a paging procedure after determining the UE corresponding to the session information, that is, the AMF sends a paging message to the AN.

S805, the AN sends a paging message to the UE.

S806, after the UE is paged, the UE initiates a service request procedure. For example, the UE sends a service request message to the AMF, the AMF receives the service request message, and sends a session context acquisition request to the SMF corresponding to the session information in S801, where the session context acquisition request carries a session identifier.

When the AN receives downlink data of other sessions of the UE again, the AN triggers a context establishment procedure according to the saved correspondence of the UE, and executes S807.

And S807, the AN determines a session identifier corresponding to the downlink data according to the stored corresponding relationship of the UE, the UE IP address and the tunnel identifier information in the downlink data, and the AN sends a session context acquisition request to the SMF corresponding to the session identifier through the AMF, wherein the session context acquisition request carries the session identifier.

S808, the SMF sends a session context acquisition response to the AN through the AMF, and carries the session context corresponding to the session identifier. The session context may be QoS information of the session, tunnel information of the UPF, etc.

It should be noted that, since the session context determined by the SMF is used for sending to the AN, the AN establishes a DRB between the AN and the UE. Therefore, the AMF does not have to understand the session context sent by the SMF, i.e. the AMF forwards the session context to the AN.

S809, the AN triggers a wireless connection establishment process between the UE and the AN according to the received session context.

Fig. 9 to 11 show the operation of AN and AMF in AN abnormal situation.

Fig. 9 shows a diagram of yet another information interaction for establishing a session provided by the present application. Fig. 9 illustrates a scenario when the AN receives downlink data again before receiving the corresponding relationship of the UE, where the method includes:

s901, the AN receives downlink data of session 1 from the UPF, and obtains the UE IP address and the tunnel identification information (i.e., session information) from the downlink data. It should be understood that "session 1" is used only to identify the session to which the downstream data belongs so as to be distinguished from the downstream data in S903, and at this time, the AN does not know to which session the downstream data belongs.

Since the AN does not store the radio connection information corresponding to the downlink data, the AN transmits a notification message or a request message to the AMF according to the method shown in fig. 6 to 8S 902. The notification message carries the session information in S901, and is used to notify the AMF that the AN receives downlink data corresponding to the session information. The request message carries session information in the downlink data of the slave session 1, and is used for requesting the AMF to send the corresponding relationship of the session information to the AN.

S903, the AN receives downlink data of session 2 from the UPF.

In this case, the processing method of the AN is two, and S904 or S905 may be selectively performed.

S904, the AN caches the downlink data of session 2, and does not send a notification message or a request message. When a response message sent by the AMF for the notification message or the request message in S902 is received, the downlink data of session 1 and session 2 are processed according to the corresponding relationship carried in the response message. Taking the method shown in fig. 7 (AN paging and AN saving the corresponding relationship) as AN example, the specific processing procedure is: determining session identifiers corresponding to the downlink data, namely session 1 and session 2, by the AN according to the corresponding relation; the AN judges the state of the UE, and decides to page the UE or directly request the SMF corresponding to the session identifier for the session context corresponding to the session 1 and the session context corresponding to the session 2 through the AMF.

When the AN selects to perform S905, that is, the AN sends a notification message or a request message to the AMF, where the notification message or the request message carries session information parsed from the downlink data of the session 2, at this time, the AMF may perform S906.

S906, the operation of the AMF is as follows: AMF does not process; or, when the AMF determines that the correspondence of the UE has been issued to the AN, the AMF sends a response message to the AN to indicate to the AN that the AMF has issued the correspondence matched with the session information in S905.

Fig. 10 shows a diagram of yet another information interaction for establishing a session provided by the present application. The following fig. 10 and 11 apply to scenarios where the UE accesses the DN through an aggregated user plane model and a session-granular user plane model simultaneously. For example, the UE accesses DN1 through the aggregated tunnel and DN2 through the session tunnel. Wherein the UE has 2 sessions over the aggregated tunnel. There are 1 session on the session tunnel.

When the downlink data on the session tunnel arrives first and the downlink data on the aggregation tunnel arrives later, the process of fig. 10 is performed. As shown in fig. 10, the method includes:

s1001a, the UPF receives the downlink data.

S1101b, the UPF sends a downlink data notification message to the SMF, where the downlink data notification message carries a session identifier to notify the SMF to trigger connection recovery of a session corresponding to the session identifier.

S1101c, the SMF sends an N11 message to the AMF, the message carries a session context, and the session context comprises QoS parameters corresponding to a session identifier, UPF tunnel information and the like.

S1002, when the AMF judges that the UE is in AN idle state, the AMF sends a paging message to the AN.

In addition, the AMF transmits the correspondence of the UE, i.e., the correspondence of session 1, the UE identity, the SMF identity, and the session information of session 1, to the AN through a message other than the paging message.

If the AMF receives a notification message or a request message from the AN at this time, as shown by S1003,

s1004, according to the method 300, the AN sends a notification message or a request message to the AMF, where the notification message or the request message carries the UE IP address and the tunnel identification information (i.e., session information) acquired from the downlink data of the session 1.

S1005, after receiving the notification message or the request message, the AMF determines, according to the correspondence stored in the AMF, that the AMF has sent the correspondence to the UE, or has paged the UE, and then the AMF operation may be as follows: not processing the received notification message or request message; or, the AMF sends a response message to the AN to indicate that the AMF has issued the corresponding correspondence to the AN or that the AMF has paged the UE.

Fig. 11 shows a diagram of yet another information interaction for establishing a session provided by the present application. When the downlink data on the aggregation tunnel arrives first and the downlink data on the session tunnel arrives later, the process of fig. 11 is performed. As shown in fig. 11, the method includes:

s1101, the AN receives downlink data of session 1 from the UPF, and obtains the UE IP address and the tunnel identification information (i.e., session information) therefrom. At this time, the AN does not know to which session the session information belongs at the bottom, and the "session 1" may be any one of the sessions.

S1102, since the AN does not know to which session the session information belongs, according to the method 300, the AN sends a notification message or AN acquisition request to the AMF, where the request message carries the session information.

S1103, after receiving the notification message or the request message, the AMF determines the UE corresponding to the session information according to the session information and the correspondence stored in the AMF. And, the AMF sends the correspondence of the UE to the AN, and/or the AMF sends a paging message to the AN.

If, thereafter, the AMF receives an N11 message from the SMF, as shown in S1104a-S1104c,

s1104a, the UPF receives the downlink data.

And S1104b, the UPF sends a downlink data notification to the SMF, and the downlink data notification carries the session identifier.

S1104c, SMF sends N11 message to AMF, carrying the session context corresponding to the session identification, including QoS parameter, UPF tunnel information, etc.

After receiving the N11 message, the AMF may perform step S1105, or perform steps S1106 and S1107.

S1105, since the AMF has already sent the UE mapping relationship to the AN and/or the AMF has triggered the paging procedure, it is not necessary to send the UE mapping relationship and/or the paging message to the AN again. Thus, the operation of the AMF may be: no treatment is done. S1106, the AMF sends a paging message to the AN.

The operation after the AN receives S1106 the paging message may be:

s1107, does not perform any processing on the paging message; alternatively, the AN sends AN acknowledgement message to the AMF to indicate that the AN has paged the UE.

Examples of the method for establishing a session provided by the present application are described above in detail. It is to be understood that the AN and AMF include corresponding hardware structures and/or software modules for performing the respective functions in order to implement the above-described 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.

In the present application, the AN and the like may be divided into functional units according to the above method examples, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one processing unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit. It should be noted that the division of the units in the present application is schematic, and is only one division of logic functions, and there may be another division manner in actual implementation.

In case of integrated units, fig. 12 shows a possible structural diagram of AN involved in the above embodiments. AN1200 includes: a processing unit 1202 and a communication unit 1203. Processing unit 1202 is configured to control and manage actions of AN1200, e.g., processing unit 1202 is configured to enable AN1200 to perform S320 of fig. 3 and/or other procedures for the techniques described herein. Communication unit 1203 is configured to support communication of AN1200 with other network entities, e.g., with AMFs. The AN1200 can also include a storage unit 1201 for storing program codes and data of the AN 1200.

The processing unit 1202 may be a processor or a controller, such as a Central Processing Unit (CPU), a general-purpose processor, a Digital Signal Processor (DSP), an application-specific integrated circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others. The communication unit 1203 may be a communication interface. The storage unit 1201 may be a memory.

The communication unit 1203 may be configured to perform the following operations: receiving first downlink data from the UPF, wherein the first downlink data comprises a first UE IP address and first tunnel identification information; sending a first message to the AMF, wherein the first message comprises a first UE IP address and first tunnel identification information; receiving a second message from the AMF, the second message including a context for establishing a first session, the first session being a session corresponding to the first UE IP address and the first tunnel identification information.

The AN1200 sends the first UE IP address and the first tunnel identification information to the AMF, and receives the context sent by the AMF for recovering the first session, so that the wireless connection between the UE and the AN corresponding to the first UE IP address and the first tunnel identification information can be recovered, and the AN1200 is prevented from discarding the first downlink data.

Optionally, the communication unit 1203 is further configured to: and receiving a third message from the AMF, wherein the third message comprises the identification of the first session, the first correspondence between the IP address of the first UE and the identification information of the first tunnel, and the third message also comprises the identification of the second session, the second correspondence between the IP address of the second UE and the identification information of the second tunnel.

When the AN1200 receives downlink data corresponding to the second session, the session corresponding to the downlink data, that is, the second session, may be determined according to the second correspondence, so that the session context corresponding to the second session is obtained from the SMF through the AMF, thereby recovering the wireless connection between the UE and the AN1200, which corresponds to the IP address of the second UE and the identification information of the second tunnel, and avoiding the AN1200 discarding the second downlink data.

Optionally, the communication unit 1203 is further configured to: receiving second downlink data from the UPF, wherein the second downlink data comprises the second UE IP address and the second tunnel identification information; sending an identification of the second session to the AMF; a context for establishing the second session is received from the AMF.

When the AN1200 receives the second downlink data, the identifier of the second session may be determined according to the second UE IP address and the second tunnel identifier included in the second downlink data, and the identifier of the second session is sent to the AMF, so that the AMF may directly send the context for recovering the second session to the AN1200 without determining the identifier of the second session according to the second UE IP address and the second tunnel identifier, which improves the response speed of the AMF and reduces the burden of the AMF.

Optionally, the communication unit 1203 is further configured to: and if the first UE is in an idle state, sending a paging message to the first UE, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

The AN1200 may select a corresponding method for recovering the first session according to the current specific situation of the first UE, for example, when the first UE is in AN idle state, the above paging method may be adopted to recover the first session, so as to avoid discarding the first downlink data by the AN 1200; when the first UE is in the connected state, the AN1200 may directly obtain the session context corresponding to the first session from the SMF corresponding to the first session through the AMF, so as to recover AN air interface connection between the AN1200 corresponding to the first session and the first UE, thereby avoiding a reduction in user experience caused by discarding the first downlink data by the AN.

Optionally, the communication unit 1203 is further configured to: and sending first downlink data to first UE through a first session, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

When the processing unit 1202 is a processor, the communication unit 1203 is a communication interface, and the storage unit 1201 is a memory, the AN referred to in the present application may be AN illustrated in fig. 13.

Referring to fig. 13, the AN1300 includes: processor 1302, communication interface 1303, memory 1301. The communication interface 1303, the processor 1302, and the memory 1301 may communicate with each other via internal connection paths to transmit control and/or data signals.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and no further description is provided herein.

In the case of integrated units, fig. 14 shows a possible structural diagram of the AMF involved in the above-described embodiment. The AMF1400 includes: a processing unit 1402 and a communication unit 1403. The processing unit 1402 is used to control and manage actions of the AMF1400, e.g., the processing unit 1402 is used to support the AMF1400 to perform S410 of fig. 4 and/or other processes for the techniques described herein. A communication unit 1403 is used to support communication of the AMF1400 with other network entities, e.g., with AN. The AMF1400 may further include a memory unit 1401 for storing program codes and data of the AMF 1400.

Processing unit 1402 may be a processor or controller, such as a CPU, general purpose processor, DSP, ASIC, FPGA or other programmable logic device, transistor logic device, hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others. The communication unit 1403 may be a communication interface or the like. The storage unit 1401 may be a memory.

The communication unit 1403 is configured to perform the following operations: receiving a first message from the AN, the first message including a first UE IP address and first tunnel identification information; and sending a second message to the AN, wherein the second message comprises a context for establishing a first session, and the first session is a session corresponding to the IP address of the first UE and the first tunnel identification information.

The AMF1400 receives the first UE IP address and the first tunnel identification information from the AN, and sends a context for recovering the first session to the AN, so that a wireless connection between the UE and the AN corresponding to the first UE IP address and the first tunnel identification information can be recovered, and the AN is prevented from discarding the first downlink data.

Optionally, the communication unit 1403 is further configured to: and if the first UE is in an idle state, sending a paging message to the first UE, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

The AMF1400 may select a corresponding method for recovering the first session according to the current specific situation of the first UE, for example, when the first UE is in AN idle state, the paging method may be adopted to recover the first session, so as to avoid the AN discarding the first downlink data; when the first UE is in the connected state, the AMF1400 may directly obtain, from the SMF corresponding to the first session, a session context corresponding to the first session, and send the session context to the AN, so that the AN recovers AN air interface connection between the AN corresponding to the first session and the first UE, thereby avoiding a reduction in user experience caused by discarding the first downlink data by the AN.

Optionally, the communication unit 1403 is further configured to: and sending a third message to the AN, wherein the third message comprises the identifier of the first session, the first corresponding relation between the IP address of the first UE and the first tunnel identifier information, and the third message also comprises the identifier of the second session, the second corresponding relation between the IP address of the second UE and the second tunnel identifier information.

When the AN receives the second downlink data, the AN may determine the identifier of the second session according to the second UE IP address and the second tunnel identifier included in the second downlink data, and send the identifier of the second session to the AMF1400, so that the AMF1400 may directly send the context for recovering the second session to the AN without determining the identifier of the second session according to the second UE IP address and the second tunnel identifier, which improves the response speed of the AMF1400 and reduces the burden of the AMF 1400.

Optionally, the communication unit 1403 is further configured to: receiving AN identification of a second session from the AN; sending a context for establishing the second session to the AN.

Optionally, the communication unit 1403 is further configured to: a first correspondence between a first UE IP address, first tunnel identification information, and an identification of a first session is obtained from the SMF.

When the processing unit 1402 is a processor, the communication unit 1403 is a communication interface, and the storage unit 1401 is a memory, the AMF referred to in the present application may be the AMF shown in fig. 15.

Referring to fig. 15, the AMF1500 includes: a processor 1502, a communication interface 1503, and a memory 1501. The communication interface 1503, the processor 1502 and the memory 1501 may communicate with each other via an internal connection path to transmit control and/or data signals.

The AN or AMF in the apparatus and method embodiments correspond exactly and the respective steps are performed by respective modules, e.g. the communication unit performs the steps of transmitting and/or receiving in the method embodiments, other steps than transmitting and/or receiving may be performed by a processing module or a processor. The functions of the specific modules can be referred to corresponding method embodiments, and are not described in detail.

The present application also provides a communication chip, which stores instructions that, when executed on AN1200 or AN1300, cause the communication chip to perform the method corresponding to the AN in the above various implementations.

The present application also provides a communication chip, in which instructions are stored, and when the communication chip runs on the AMF1400 or the AMF1500, the communication chip executes the method corresponding to the AMF in the above various implementations.

In the embodiments of the present application, the sequence numbers of the processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the inherent logic of the processes, and should not limit the implementation processes of the present application.

In addition, the term "and/or" herein is only one kind of association relationship describing an 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.

The steps of a method or algorithm described in connection with the disclosure herein may be embodied in hardware or in software instructions executed by a processor. The software instructions may be comprised of corresponding software modules that may be stored in Random Access Memory (RAM), flash memory, Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), registers, a hard disk, a removable disk, a compact disc read only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC. Additionally, the ASIC may reside in AN AN or AMF. Of course, the processor and the storage medium may reside as discrete components in the AN and AMF.

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 in or transmitted over a computer-readable storage medium. The computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)), or wirelessly (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., Digital Versatile Disk (DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), etc.

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.

Claims

1. A method of establishing a session, the method comprising:

the method comprises the steps that AN access network AN device receives first downlink data from a user plane function UPF device, wherein the first downlink data comprises a first user equipment UE network protocol IP address and first tunnel identification information;

the AN equipment sends a first message to access and mobility management function (AMF) equipment, wherein the first message comprises the IP address of the first UE and the identification information of the first tunnel;

the AN equipment receives a second message from the AMF equipment, wherein the second message comprises a context for establishing a first session, and the first session is a session corresponding to the first UE IP address and the first tunnel identification information.

2. The method of claim 1, further comprising:

the AN equipment receives a third message from the AMF equipment, wherein the third message comprises the identifier of the first session, the first corresponding relation between the IP address of the first UE and the first tunnel identifier information, and the third message also comprises the identifier of the second session, the IP address of the second UE and the second corresponding relation between the second tunnel identifier information.

3. The method of claim 2, further comprising:

the AN equipment receives second downlink data from the UPF equipment, wherein the second downlink data comprises the second UE IP address and the second tunnel identification information;

the AN equipment sends the identification of the second session to the AMF equipment;

the AN device receives a context for establishing the second session from the AMF device.

4. A method according to claim 2 or 3, characterized in that the method further comprises:

and if the first UE is in AN idle state, the AN equipment sends a paging message to the first UE, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

5. The method according to any of claims 1 to 3, wherein the first tunnel identification information is at least one of a tunnel identification, tunnel information of AN device side and tunnel information of UPF device side.

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

and the AN equipment sends the first downlink data to first UE through the first session, wherein the first UE is the UE corresponding to the first UE IP address and the first tunnel identification information.

7. A method of establishing a session, the method comprising:

receiving a first message from access network AN equipment by access and mobility management function AMF equipment, wherein the first message comprises a first user equipment UE network protocol IP address and first tunnel identification information;

and the AMF equipment sends a second message to the AN equipment, wherein the second message comprises a context for establishing a first session, and the first session is a session corresponding to the IP address of the first UE and the identification information of the first tunnel.

8. The method of claim 7, further comprising:

and if the first UE is in an idle state, the AMF equipment sends a paging message to the first UE, wherein the first UE is the UE corresponding to the IP address of the first UE and the first tunnel identification information.

9. The method of claim 7, further comprising:

the AMF equipment sends a third message to the AN equipment, wherein the third message comprises the identifier of the first session, the first corresponding relation between the IP address of the first UE and the first tunnel identifier information, and the third message also comprises the identifier of the second session, the second IP address of the second UE and the second corresponding relation between the second tunnel identifier information.

10. The method of claim 9, further comprising:

the AMF device receiving AN identification of the second session from the AN device;

the AMF device sends a context for establishing the second session to the AN device.

11. The method according to any one of claims 7 to 10, further comprising:

and the AMF equipment acquires a first corresponding relation among the IP address of the first UE, the identification information of the first tunnel and the identification of the first session from a Session Management Function (SMF) equipment.

12. The method according to any of claims 7 to 10, wherein the first tunnel identification information is at least one of a tunnel identification, tunnel information of AN device side, and tunnel information of a UPF device side.

13. An apparatus for establishing a session, comprising a communication unit configured to:

receiving first downlink data from a User Plane Function (UPF) device, wherein the first downlink data comprises a first User Equipment (UE) network protocol (IP) address and first tunnel identification information;

sending a first message to an access and mobility management function (AMF) device, wherein the first message comprises the first UE IP address and the first tunnel identification information;

receiving a second message from the AMF device, the second message including a context for establishing a first session, the first session being a session corresponding to the first UE IP address and the first tunnel identification information.

14. The apparatus of claim 13, wherein the communication unit is further configured to:

receiving a third message from the AMF device, wherein the third message comprises an identifier of the first session, a first correspondence between the first UE IP address and the first tunnel identifier information, and the third message further comprises a second correspondence between an identifier of the second session, a second UE IP address and the second tunnel identifier information.

15. The apparatus of claim 14, wherein the communication unit is further configured to:

receiving second downlink data from the UPF device, wherein the second downlink data comprises the second UE IP address and the second tunnel identification information;

sending an identification of the second session to the AMF device;

receiving a context for establishing the second session from the AMF device.

16. The apparatus of claim 14 or 15, wherein the communication unit is further configured to:

and if the first UE is in an idle state, sending a paging message to the first UE, wherein the first UE is the UE corresponding to the first UE IP address and the first tunnel identification information.

17. The apparatus according to any of claims 13 to 15, wherein the first tunnel identification information is at least one of a tunnel identification, tunnel information of AN device side, and tunnel information of a UPF device side.

18. The apparatus according to any of claims 13 to 15, wherein the communication unit is further configured to:

and sending the first downlink data to first UE through the first session, wherein the first UE is the UE corresponding to the first UE IP address and the first tunnel identification information.

19. An apparatus for establishing a session, comprising a communication unit configured to:

receiving a first message from AN access network AN device, wherein the first message comprises a first User Equipment (UE) network protocol IP address and first tunnel identification information;

and sending a second message to the AN device, wherein the second message comprises a context for establishing a first session, and the first session is a session corresponding to the first UE IP address and the first tunnel identification information.

20. The apparatus of claim 19, wherein the communication unit is further configured to:

21. The apparatus of claim 19, wherein the communication unit is further configured to:

and sending a third message to the AN device, wherein the third message comprises the identifier of the first session, the first corresponding relation between the IP address of the first UE and the first tunnel identifier information, and the third message further comprises the identifier of the second session, the second corresponding relation between the IP address of the second UE and the second tunnel identifier information.

22. The apparatus of claim 21, wherein the communication unit is further configured to:

receiving AN identification of the second session from the AN device;

sending a context for establishing the second session to the AN device.

23. The apparatus according to any of claims 19 to 22, wherein the communication unit is further configured to:

and acquiring a first corresponding relation among the IP address of the first UE, the first tunnel identification information and the identification of the first session from a Session Management Function (SMF) device.

24. The apparatus according to any of claims 19 to 22, wherein the first tunnel identification information is at least one of a tunnel identification, tunnel information of AN device side, and tunnel information of a UPF device side.