WO2019076195A1

WO2019076195A1 - Mobility management method, terminal, and core network device

Info

Publication number: WO2019076195A1
Application number: PCT/CN2018/109002
Authority: WO
Inventors: 窦凤辉; 金辉; 欧阳国威; 杨皓睿; 李小娟
Original assignee: 华为技术有限公司
Priority date: 2017-10-16
Filing date: 2018-09-30
Publication date: 2019-04-25
Also published as: CN109673046A; CN109673046B

Abstract

The embodiments of the present application relate to a mobility management method, a terminal, and a core network device. A terminal has a PDU session of a LAND, and said method comprises: when a first condition is satisfied, the terminal sending a registration request or a service request to a core network device, the first condition including the terminal in an idle state moving to a LADN service area. According to the embodiments of the present application, when the terminal in an idle state moves to the LADN service area, the LADN service can be continued, reducing the possibility of data loss, saving signaling resources.

Description

Mobility management method, terminal and core network device

This application claims the priority of the Chinese Patent Application filed on October 16, 2017, the Chinese Patent Office, the application number is 201710963070.0, and the application is entitled "Moving Management Method, Terminal and Core Network Equipment", the entire contents of which are incorporated by reference. In this application.

Technical field

The embodiments of the present invention relate to the field of communications technologies, and in particular, to a mobility management method, a terminal, and a core network device.

Background technique

In the 5G network, the concept of the Local Area Data Network (LADN) is introduced. When the terminal is in the Registration Procedure, the access and mobility management function (AMF) provides the terminal with the access and mobility management function (AMF). LADN information (for example, LADN availability information), LADN availability information includes LADN data network name (LADN DNN) and LADN service area (LADN Service Area), which is a terminal registration area A specific tracking area (TA) within a group, when the terminal is located within the LADN Service Area, a protocol data unit (PDU) session with the LADN can be established. When the terminal moves out of the LADN Servcie Area After that, the transfer of LADN-based data will not be possible.

Generally, the Access and Mobility Management Function (AMF) provides a session management function (SMF) with information about whether the terminal is in the LADN Service Area, so that the SMF determines whether the terminal can establish a LADN session, or The established LADN session is managed to ensure that the LADN-based data can be transmitted only when the terminal is in the LADN Service Area.

After the SMF determines that the terminal moves out of the LADN service area, the user plane function (UPF) may be notified to discard the downlink data of the session of the LADN or stop sending Downlink Data Notification (DDN) related to the session to the SMF. However, when the terminal is in the idle state, the network cannot know the exact location of the terminal when the terminal is in the idle state, and when the terminal is in the idle state, even if it is located in the LADN service area, if the downlink data of the LADN PDU session arrives, the UPF It also does not send DDN to the SMF, causing data loss.

Summary of the invention

The embodiment of the present application provides a mobility management method, a terminal, and a core network device. To achieve the management of the session accessing the LADN, the problem of data loss or signaling waste is reduced. Among them, Mobility Management can be understood as a management method or management process related to terminal mobility, such as Attach/Detach, Registration Procedure, Service Request, The NAS signaling connection release, the Handover procedure Reachability, and the Mobility restriction can be understood as related aspects of mobility management.

In a first aspect, a method of mobility management is provided. The terminal has a PDU session of the LADN. The method includes: when the first condition is met, the terminal sends a registration request or a service request to the core network device. The first condition includes the terminal moving to the LADN service area in an idle state. With the embodiment of the present application, when the terminal moves to the LADN service area in the idle state, the terminal can continue the LADN service, which reduces the possibility of data loss and saves signaling resources.

In a first optional implementation of the first aspect, the first condition further includes: when the terminal enters an idle state, the terminal is located outside the LADN service area; or, when the terminal is outside the LADN service area, the terminal enters Connection state. With the embodiment of the present application, when the core network device only knows that the terminal is outside the LADN service area, the registration process or the service request process is triggered, which makes the mobility management more reasonable and further saves signaling.

In a second optional implementation of the first aspect, before the terminal sends the registration request or the service request to the core network device, the method further includes: when the terminal enters the idle state, the terminal determines whether the terminal is located outside the LADN service area. . The embodiment of the present application can be implemented, and it is more reasonable to determine the timing and location of the terminal to determine whether it is located in the LADN service area.

In a third alternative implementation of the first aspect, the method further comprises: when the terminal is outside the LADN service area, the terminal determines whether to move into the LADN service area. Through the detection of the LADN service area by the terminal in the embodiment of the present application, the LADN service is continued in time.

In a fourth optional implementation of the first aspect, the method further includes: before the terminal sends the registration request or the service request to the core network device, the method further includes: when the terminal is located outside the LADN service area, the terminal determines whether the terminal enters When the terminal enters the connected state, the terminal saves the target information, and the target information includes when the terminal is outside the LADN service area, the terminal enters the connected state.

In a fifth alternative implementation of the first aspect, when the terminal enters an idle state, the terminal determines that the terminal is located outside the LADN service area according to the target information.

In a sixth alternative implementation of the first aspect, the method further comprises: when the terminal is outside the LADN service area, the terminal determines whether to move into the LADN service area.

In a seventh optional implementation of the first aspect, the method further includes: when the terminal enters the connected state or the terminal enters the LADN service area, the terminal releases the target information. The embodiment of the present application can be implemented to release the target information when it fails, thereby saving resources.

It should be noted that, in this embodiment of the present application, releasing information or parameters may include deleting information or parameters.

In an eighth optional implementation of the first aspect, the terminal determining to enter the LADN service area includes: the terminal acquiring the tracking area identifier TAI; and when the TAI belongs to the LADN service area, the terminal determines to enter the LADN service area. The embodiment of the present application can implement the detection of whether the terminal enters the LADN service area, so as to continue the LADN service in time.

In a ninth optional implementation of the first aspect, before the terminal sends the registration request or the service request to the core network device, the method further includes: receiving, by the terminal, the first parameter sent by the core network device, where the first parameter is used to indicate that the terminal is When the first condition is met, the registration request or the service request is sent to the core network device; or the first parameter is used to notify the terminal that the downlink data of the PDU session accessing the LADN is notified that the DDN is unavailable. According to the embodiment of the present application, the terminal may determine, according to information sent by the core network device, whether the location of the terminal that the core network device knows is located in the LADN service area, so that the information is more synchronized, and signaling is saved.

In a tenth optional implementation of the first aspect, the first parameter includes at least one of the following: an identifier of a PDU session of the LADN; a data network name DNN corresponding to the LADN; and indication information indicating the downlink data notification DDN is not available. The embodiment of the present application can implement that the core network device indicates that the DNN of the PDU session of the LADN service area is unavailable, so that the information is more synchronized, and signaling is saved.

In an eleventh optional implementation of the first aspect, after the terminal receives the first parameter sent by the core network device, the terminal further includes: after the terminal moves into the LADN service area, the terminal releases the first parameter; the terminal receives The second parameter sent by the core network device, the terminal releases the first parameter according to the second parameter; after the terminal sends the registration request or the service request to the core network device, the terminal releases the first parameter. The embodiment of the present application can implement release when the first parameter fails, thereby saving resources.

With the embodiment of the present application, when the terminal moves to the LADN service area in the idle state, the terminal can continue the LADN service, which reduces the possibility of data loss and saves signaling resources.

In a second aspect, a method of mobility management is provided. The terminal saves the LADN service area, and the method includes: when the first condition is met, the terminal triggers a registration process or a service request process; wherein the first condition includes the terminal moving into the LADN service area in an idle state. With the embodiment of the present application, when the terminal moves to the LADN service area in the idle state, the terminal can continue the LADN service, which reduces the possibility of data loss and saves signaling resources.

In a first optional implementation of the second aspect, the first condition further includes at least one of the following: a PDU session in which the terminal has a LADN; when the terminal enters an idle state, the terminal is located outside the LADN service area; or, While the terminal is outside the LADN service area, the terminal enters the connected state. Through the embodiment of the present application, the PDU session in which the LADN exists can be implemented, and the registration process or the service request process is triggered, which further saves signaling. Even in the case where it is determined that the core network device only knows that the terminal is outside the LADN service area, the registration process or the service request process is triggered, which makes the mobility management more reasonable and further saves signaling.

In a second optional implementation of the second aspect, when the terminal enters the idle state, the terminal is located outside the LADN service area, and includes at least one of the following: when the terminal enters the idle state, the terminal determines that the terminal is located in the LADN service area. Alternatively, the terminal stores the first information, and the first information includes when the terminal enters the idle state, the terminal is located outside the LADN service area. The embodiment of the present application can be implemented, and it is more reasonable to determine the timing and location of the terminal to determine whether it is located in the LADN service area.

In a third optional implementation of the second aspect, the method further includes: when the terminal enters the connected state or the terminal enters the LADN service area, the terminal releases the first information. The embodiment of the present application can be implemented to release the first information when the first information fails, thereby saving resources.

In a fourth optional implementation of the second aspect, the terminal enters the connected state during the period when the terminal is located outside the LADN service area, including: the terminal stores the second information, where the second information includes when the terminal is located in the LADN service area. During the outer period, the terminal enters the connected state. The embodiment of the present application can be implemented, and it is more reasonable to determine the timing and location of the terminal to determine whether it is located in the LADN service area.

In a fifth optional implementation of the second aspect, the method further includes: when the terminal enters the connected state or the terminal enters the LADN service area, the terminal releases the second information. The embodiment of the present application can be implemented to release the second information when it fails, thereby saving resources.

In a sixth optional implementation of the second aspect, before the terminal triggers the registration process or the service request process, the method further includes: the terminal triggering detection of the process of entering the LADN service area. The embodiment of the present application can implement the detection of whether the terminal enters the LADN service area, so as to continue the LADN service in time.

In a seventh optional implementation of the second aspect, the terminal triggers a process of detecting entry into the LADN service area, including:

The terminal acquires the tracking area identifier TAI; when the TAI belongs to the LADN service area, the terminal determines to enter the LADN service area. The embodiment of the present application can implement the detection of whether the terminal enters the LADN service area, so as to continue the LADN service in time.

In an eighth optional implementation of the second aspect, the first condition further includes: receiving, by the terminal, the first parameter sent by the core network device, where the first parameter is used to indicate that the terminal triggers the registration request process when determining that the first condition is met Or the service request process; or the first parameter is used to indicate that the terminal learns that the downlink data of the protocol data unit PDU session of the LADN is notified that the DDN is unavailable. According to the embodiment of the present application, the terminal may determine, according to information sent by the core network device, whether the location of the terminal that is known by the core network device is located in the LADN service area, so that the information is more synchronized, and signaling is saved.

In a ninth optional implementation of the second aspect, before the terminal triggers the registration process or the service request process, the method further includes one or more of the following: the terminal receives the identifier of the protocol data unit PDU session of the LADN sent by the core network device. Or, the terminal receives the data network name DNN corresponding to the LADN. The embodiment of the present application can implement that the core network device indicates that the DNN of the PDU session of the LADN service area is unavailable, so that the information is more synchronized, and signaling is saved.

In a tenth optional implementation of the second aspect, after receiving the first parameter sent by the core network device, the terminal further includes one or more of the following: after the terminal moves into the LADN service area, the terminal releases the first parameter. The terminal receives the second parameter sent by the core network device, and the terminal releases the first parameter according to the second parameter; or, after the terminal triggers the registration request process or the service request process, the terminal releases the first parameter. The embodiment of the present application can implement release when the first parameter fails, thereby saving resources.

In an eleventh optional implementation of the second aspect, the terminal triggers the registration process, including: the terminal sends a registration request to the AMF, where the registration request includes one or more of the data network name DNN corresponding to the LADN or the indication information. Wherein the DNN is used to identify the LADN; the indication information is used to indicate that the terminal enters the LADN service area. The embodiment of the present application can be implemented, and the terminal can continue the LADN service by using the registration request.

In a twelfth optional implementation of the second aspect, the terminal triggers the service request process, including: the terminal sends a service request to the access and mobility management entity AMF, where the service request includes a data network name DNN or an indication corresponding to the LADN. One or more of the information, wherein the DNN is used to identify the LADN; the indication information is used to indicate that the terminal enters the LADN service area. The embodiment of the present application can be implemented, and the terminal can continue the LADN service by using the service request.

In a third aspect, a method of mobility management is provided. The first core network device has a PDU session of the LADN, and the method includes: the first core network device sends a first request to the second core network device, where the first request is used to request that the second core network device not send the message to the first core network device. The downlink data of the PDU session is notified to the DDN; the first core network device sends a first parameter to the terminal, where the first parameter is used to indicate that the terminal sends a registration request or a service request to the first core network device when the terminal determines that the first condition is met, where A condition includes the terminal moving into the LADN service area in an idle state; or, the first parameter is used to notify the terminal that the DDN of the PDU session is unavailable. With the embodiment of the present application, when the terminal moves to the LADN service area in the idle state, the terminal can continue the LADN service, which reduces the possibility of data loss and saves signaling resources.

In a first optional implementation of the third aspect, the first parameter includes at least one of the following: an identifier of a PDU session of the LADN; or a data network name DNN corresponding to the LADN; indication information indicating that the information is used to indicate the downlink The data informs DDN that it is not available.

In a second optional implementation of the third aspect, after the first core network device sends the first parameter to the terminal, the method further includes: the first core network device sends a second parameter to the terminal, where the second parameter is used to indicate that the terminal is released The first parameter; or the second parameter is used to notify the downlink data of the terminal PDU session that the DDN is available.

In a fourth aspect, a terminal is provided. The terminal has a protocol data unit PDU session of the local area data network LADN, and the terminal includes: a sending unit, configured to send a registration request or a service request to the core network device when the first condition is met; wherein the first condition includes the terminal being idle Move to the LADN service area.

In a first optional implementation of the fourth aspect, the first condition further includes: when the terminal enters an idle state, the terminal is located outside the LADN service area; or, when the terminal is outside the LADN service area, the terminal enters Connection state.

In a second optional implementation of the fourth aspect, the method further includes: determining, when the terminal enters an idle state, determining whether the terminal is located outside the LADN service area.

In a third alternative implementation of the fourth aspect, the determining unit is further configured to determine whether to move into the LADN service area when the terminal is outside the LADN service area.

In a fourth alternative implementation of the fourth aspect,

The determining unit is further configured to: when the terminal is located outside the LADN service area, determine whether the terminal enters a connected state; and the saving unit is configured to save target information when the terminal enters a connected state, The target information includes the terminal entering an over-connected state when the terminal is outside the LADN service area.

In a fifth optional implementation of the fourth aspect, the determining unit is further configured to: when the terminal enters an idle state, determine, according to the target information, that the terminal is located outside the LADN service area.

In a sixth alternative implementation of the fourth aspect, the determining unit is further configured to determine whether to move into the LADN service area when the terminal is located outside the LADN service area.

In a seventh optional implementation of the fourth aspect, the method further includes a release unit, configured to release the target information when the terminal enters a connected state or the terminal enters the LADN service area.

In an eighth optional implementation of the fourth aspect, the determining unit is specifically configured to: obtain the tracking area identifier TAI; and when the TAI belongs to the LADN service area, determine to enter the LADN service area.

In a ninth optional implementation of the fourth aspect, the method further includes: a receiving unit, configured to receive a first parameter sent by the core network device, where the first parameter is used to indicate that the terminal sends the core network device to the core network device when the first condition is met. Sending a registration request or a service request; or, the first parameter is used to notify the downlink data of the PDU session of the terminal LADN that the DDN is unavailable.

In a tenth optional implementation of the fourth aspect, the first parameter includes at least one of the following: an identifier of a PDU session of the LADN; a data network name DNN corresponding to the LADN; or an indication information indicating the downlink The data informs DDN that it is not available.

In an eleventh optional implementation of the fourth aspect, the method further includes: a releasing unit, configured to: after the terminal moves into the LADN service area, the terminal releases the first parameter; or, the receiving unit is further configured to receive the core network device The second parameter sent;

a releasing unit, configured to release the first parameter according to the second parameter; or a releasing unit, configured to release the first parameter after the terminal sends the registration request or the service request to the core network device.

In a fifth aspect, a core network device is provided. The core network device is applicable to the first core network device, and the first core network device has a protocol data unit PDU session of the local area data network LADN, and the core network device includes: a sending unit, configured to send the first request to the second core network device. The first request is used to request the second core network device not to send the downlink data notification DDN of the PDU session to the first core network device. The sending unit is further configured to send the first parameter to the terminal, where the first parameter is used to indicate that the terminal determines that the terminal is satisfied. The first condition is: sending a registration request or a service request to the first core network device, where the first condition includes the terminal moving in the idle state to the LADN service area; or the first parameter is used to notify the terminal that the DDN of the PDU session is unavailable. use.

In a first alternative implementation of the fifth aspect, the first parameter includes at least one of: an identifier of a PDU session of the LADN; or a data network name DNN corresponding to the LADN; indication information indicating that the information is used to indicate the downlink The data informs DDN that it is not available.

In a second optional implementation of the fifth aspect, the sending unit is further configured to: send, to the terminal, a second parameter, where the second parameter is used to indicate that the terminal releases the first parameter; or the second parameter is used to notify the terminal of the PDU session The downstream data informs DDN that it is available.

In a sixth aspect, there is provided a terminal having the functionality to implement the terminal behavior of the first aspect described above and its alternative implementation or of the second aspect and its alternative implementation. The functions may be implemented by hardware or by corresponding software implemented by hardware. The hardware or software includes one or more modules corresponding to the functions described above. With the embodiment of the present application, when the terminal moves to the LADN service area in the idle state, the terminal can continue the LADN service, which reduces the possibility of data loss and saves signaling resources.

In a seventh aspect, a core network device is provided, the core network device having a function of implementing core network device behavior in the third aspect and optionally implemented therein. The functions may be implemented by hardware or by corresponding software implemented by hardware. The hardware or software includes one or more modules corresponding to the functions described above. With the embodiment of the present application, when the terminal moves to the LADN service area in the idle state, the terminal can continue the LADN service, which reduces the possibility of data loss and saves signaling resources.

According to an eighth aspect, there is provided a computer readable storage medium having stored thereon a computer program, the computer program being executed by a processor to implement any one of the first aspect, the second aspect, and the third aspect described above Aspect or aspect of the method described.

A ninth aspect, a computer program product comprising instructions for causing a computer to perform any one or more of the above aspects, the second aspect, and the third aspect, when the instructions are run on a computer method.

DRAWINGS

1 is a schematic structural diagram of a 5G communication network;

Figure 2 is a schematic diagram of a LADN service area.

FIG. 3 is a schematic diagram of signaling interaction of a mobility management method according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of signaling interaction of another mobility management method according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of signaling interaction of another mobility management method according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of a terminal according to an embodiment of the present application;

FIG. 7 is a schematic structural diagram of a core network device according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of another terminal according to an embodiment of the present disclosure;

FIG. 9 is a schematic structural diagram of another core network device according to an embodiment of the present application.

Detailed ways

The embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application.

The embodiment of the present application provides a method and a device for mobility management, which are applied to a 5G communication network.

In the embodiment of the present application, the terminal may be a device that provides voice and/or data connectivity to the user, a handheld device with wireless connectivity, or other processing device connected to the wireless modem. The terminal can communicate with one or more core networks via a Radio Access Network (RAN), and the terminal can be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal device. For example, it may be a portable, pocket, handheld, computer built-in or in-vehicle mobile device that exchanges language and/or data with a wireless access network. For example, personal communication service (PCS) telephone, cordless telephone, session initiated protocol (SIP) telephone, wireless local loop (WLL) station, personal digital assistant (personal digital assistant, PDA) and other equipment. A terminal may also be called a system, a subscriber unit, a subscriber station, a mobile station, a mobile, a remote station, an access point, and a remote. The remote terminal, the access terminal, the user terminal, the user agent, the user device, or the user equipment are not in the embodiment of the present application. limited. According to the service type, the terminal involved in the embodiment of the present application may be a terminal device with high demand for speed and mobility, such as a mobile phone, a multimedia device, or the like, or an Internet of Things terminal, or a car network. Terminal.

FIG. 1 is a schematic structural diagram of a 5G communication network according to an embodiment of the present application.

As shown in FIG. 1, an authentication service function (AUSF), an AMF, an SMF, a unified data management (UDM), an application function entity (AF), and a policy control function entity ( The policy control function (PCF) and the UPF may be one or more servers in the core network of the 5G communication network, which are collectively referred to as core network devices in this embodiment of the present application. The terminal can realize network interconnection by accessing the communication network. For example, a PDU session can be established through the access communication network to perform data transmission with the UPF, and the PDU session can be managed by the SMF.

The function of each module in the 5G communication network is briefly introduced below.

AUSF is primarily used for authentication.

The AMF has terminal mobility management, registration management, connection management, lawful interception, support for session management (SM) information between the transmission terminal and the SMF, access authentication and access authorization. The AMF can determine information such as TA, RA, and LADN of the terminal.

SMF has functions such as session management and roaming. Among them, session management functions, for example, session establishment, modification, and release, include tunnel maintenance of UPF and access network (AN) nodes. The roaming function may include charging data collection, and signaling transmission supporting authentication/authorization with an external data network (DN). For example, the SMF can be used to manage the PDU session of the LADN, including modifying or releasing the LADN PDU session, receiving the DDN corresponding to the LADN PDU session, and the like.

UPF has functions such as packet routing and lawful interception. The UPF can route and legally listen to packets corresponding to the LADN PDU session.

UDM has the functions of authentication certificate processing, user identification processing, access authorization, registration and mobility management, subscription management, and SMS management.

The AF can interact with the 3GPP core network.

The PCF is able to support policy frameworks as well as policy rules.

The interface between the entities can be specifically referred to the 3GPP standard. It should be noted that the 5G communication network structure shown in FIG. 1 is only an example, and the 5G communication network structure used in the embodiment of the present application may include more or less network devices.

The applicant of the present application finds that the LADN in the 5G network has a certain relationship with the RA. The tracking area (TA) in the RA can support the LADN in whole or in part, or the TA in the RA can all not support. LADN.

It can be understood that the TA support LADN refers to the service area where the TA belongs to the LADN, that is, when the terminal is in the coverage of the TA, the PDU session of the LADN can be established through the base station under the TA and the data is performed on the PDU session of the LADN. transmission. The TA does not support the LADN. The TA does not belong to the service area of the LADN. That is, when the terminal is in the coverage of the TA, the LADN PDU session cannot be established. For the PDU session of the established LADN, the corresponding user plane connection cannot be activated. transmission.

For example, as shown in FIG. 2, FIG. 2 is a schematic diagram of a LADN service area. TA1-TA12 constitutes a total of three RAs (RA1-RA3), of which TA1-TA5 supports LADN. At this time, all the TAs in the RA1 support the LADN, and the RA1 is considered to include the LADN service area; if the TA in the RA2 supports the LADN only if the TA5 supports the LADN, the RA2 in the RA3 does not support the LADN. It is considered that the LADN service area is not included in the RA3. That is, the LADN can be distributed across the RA. The LADN service area information is configured by the network to the AMF, and then sent by the AMF to the terminal. However, the LADN service area sent by the AMF to the terminal can include only at least one TA supporting the LADN in the current RA, that is, the current RA and The intersection of LADN service areas. For example, as shown in FIG. 2, when the current RA of the terminal is RA1, the LADN service area sent by the AMF to the terminal includes TA1-TA4, and when the current RA of the terminal is RA2, the LADN service area sent by the AMF to the terminal includes TA5, When the current RA of the terminal is RA3, the AMF may not send the LADN service area information to the terminal or the TADN service area does not have a TA.

During the terminal registration process, the AMF sends the LADN information to the terminal, where the LADN information includes the LADNDNN, the LADN service area, etc., when the LADN information changes, the AMF may send the updated LADN information to the terminal through the NAS message, such as through the UE. Configure the update message (UE configuration update command).

The embodiments of the present application are further described below with reference to the accompanying drawings.

FIG. 3 is a schematic diagram of signaling interaction of a method for mobility management according to an embodiment of the present disclosure. The terminal has a LADN PDU session. It can be understood that the PDU session of the LADN may mean that the DNN attribute corresponding to the PDU session is a LADN DNN, or the PDU session is a connection for the terminal to access the LADN, or the PDU session is used between the terminal and the LADN. The connection to transfer data. In 4G, a PDU session may also refer to a public/packet data network connection (PDN connection). Further, the PDU session in which the terminal has the LADN can be understood as one or more of the following:

The terminal establishes a PDU session with LADN;

The terminal establishes a PDU session with LADN. The user plane connection of the PDU session may or may not exist. The user plane connection of the PDU session may include a connection between the terminal and the access node, such as a radio bearer DRB and an access node. The connection between the S-GW and the P-GW, such as the connection between the gateway, such as the UPF, the S-GW, or the P-GW, and between the gateway and the gateway, such as the UPF. Further, the presence of the user plane connection means that the foregoing connections are established, and the terminal can directly send the user plane data through the foregoing connection; if the user plane connection does not exist, it means that one or more of the foregoing connections are not established, and the terminal cannot directly Send user plane data. If the terminal needs to send user plane data, you need to establish the corresponding connection first.

The context of the PDU session in which the LADN is stored on the terminal;

The context of the PDU session may include one or more of the following: an identifier of the PDU session; a session service continuity (SSC) mode of the PDU session; a type of the PDU session such as an IP type, an ethernet type , unstructured type, etc.; data network name (DNN) corresponding to the PDU session; network slice information corresponding to the PDU session, for example, single network slice selection information (S-NSSAI) , network slice identifier NSI, etc.; QoS flow identifier (QFI) of the PDU session, QoS parameters corresponding to the QoS flow, such as 5G QoS Indicator (5QI), guaranteed flow bit rate (GFBR) ), maximum flow rate (MFBR), session aggregate maximum bit rate (Session-AMBR), radio bearer information corresponding to the PDU session, such as Data Radio Bearer (DRB) .

Further, the terminal saves the LADN service area, that is, in the terminal registration process, the core network device sends the LADN service area to the terminal, or after the terminal registers, the core network device updates the LADN service area, and the terminal receives the LADN service area. It saves, for example, the core network device updates the LADN service area via NAS messages. It should be noted that the core network device may be an AMF, an SMF, or another core network device. The specific name or type of the core network device is not limited in this embodiment. As shown in FIG. 3, the method specifically includes:

S310. When the terminal meets the first condition, the terminal sends a registration request or a service request to the core network device. The first condition includes that the terminal moves into the LADN service area in an idle state. The terminal moves to the LADN service area in the idle state. It can be understood that the terminal is in the idle state, that is, when the connection management (CM) status of the terminal is CM-IDLE, in the registration area RA, the TA of the LADN is never supported. Move to the TA that supports LADN. The core network device can determine the location of the terminal through the terminal-triggered registration process or the service request process, so as to provide the LADN-related service to the terminal when determining that the terminal enters the LADN service area. For example, when determining that the terminal enters the LADN service area, one or more operations may be performed: the SMF notifies the UPF to send the DDN of the LADN-related PDU session; the SMF notifies the UPF to send the data of the LADN-related PDU session; the SMF triggers the service request process to Activate the user plane connection for the LADN related PDU session. For example, as shown in FIG. 2, if the current RA of the terminal is RA2, the first condition includes that the terminal is in RA2 and moved from TA6 to TA5.

It should be noted that the terminal in the idle state means that the connection management state of the terminal is CM-IDLE, and the terminal is in the CM-IDLE feature may be a combination of one or more of the following: there is no NAS signaling connection between the terminal and the AMF. Signaling connection between the terminal and the AN (for example, radio resource control (RRC) connection), signaling connection between AN and AMF (for example, N2 connection), signaling between AN and AMF Connections (for example, N3 connections) do not exist. Correspondingly, the terminal can also be in a connected state. In the connected state, the connection management state is CM-CONNECTED, that is, there is a signaling connection between the terminal and the core network. For example, there is a NAS signaling connection between the terminal and the AMF, or a NAS signaling connection exists between the terminal and the MME.

It can be understood that the terminal sends a registration request or a service request, which is essentially a terminal triggering a registration process or a service request process, and the purpose thereof is mainly to enable the core network device to perceive that the terminal has moved into the LADN service area, so that the core network device can be normally operated. The DDN or downlink data of the session that sent the LADN. The terminal triggers the registration process, and the terminal may send a registration request to the AMF, or the terminal may send a registration area (Tracking area) update request (Registration (Tracking) Area Update request) to the AMF, or the terminal may send the request to the AMF. Other NAS messages, the embodiment of the present application does not specifically limit the message name. The terminal triggers the service request process, and the terminal may send a service request to the AMF, or the terminal may send an extended service request to the AMF, or the terminal may send another NAS message to the AMF. The name of the message is not specifically limited.

Further, when the radio resource control RRC connection of the terminal is in the RRC inactive state, if the terminal moves from the LADN service area to the LADN service area, the terminal may also trigger the RRC connection recovery process to allow the core network device to perceive. Move to the LADN service area to the terminal. In this scenario, the terminal sends an RRC Connection Resume Request (RRC Connection Resume Request) to the AN, or sends an AN-level Paging Area Update (PAU) or other RRC message. When considering RRC inactive, the first condition further includes that the terminal moves into the LADN service area in the RRC inactive state.

It should be noted that the RRC inactive state means that the RRC connection between the terminal and the AN is disconnected, but the related RRC connection context is still stored on the terminal and the AN. In this case, it can also be understood that the RRC connection is suspended. The RRC connection can be recovered when needed. The RRC connection context includes one or more of the following: signaling bearer configuration SRB information, radio bearer configuration DRB information, RRC connection recovery identifier Resume ID, and the like. When the RRC connection of the terminal is in RRC inactive, the CM status of the terminal may be CM-CONNECTED, and the connection between the AN and the core network gateway and between the core network gateway and the core network gateway may or may not exist. Correspondingly, the RRC state further includes RRC connected, and the RRC connected means that the RRC connection between the terminal and the AN is established. Optionally, the first condition may further include one or more of the following:

(1) When the terminal enters the idle state, the terminal is located outside the LADN service area.

It can be understood that the terminal enters an idle state, including transitioning from a connected state to an idle state. The terminal is located outside the LADN service area. It can be understood that the TA where the terminal is currently located is not included in the LADN service area. Correspondingly, the terminal located in the LADN service area means that the TA where the terminal is currently located is included in the LADN service area. Further, the terminal is located outside the LADN service area and can be determined by the terminal. In one implementation manner, the terminal acquires the TAI corresponding to the current cell, determines whether the TAI belongs to the LADN service area, and if it belongs to the LADN service area, if not, if not It belongs to the LADN service area. The terminal obtains the TAI corresponding to the current cell, and may obtain the TAI corresponding to the resident cell saved by the terminal, or may be obtained by reading the system information of the cell.

It should be noted that the terminal enters an idle state, which can be understood as a combination of one or more actions: the terminal releases an AN signaling connection with the access node AN, such as an RRC connection; and the connection management state of the terminal The conversion to CM-IDLE, the terminal release and the signaling connection between the AN means that the terminal deletes the signaling connection with the AN.

Further, when the terminal enters the idle state, the terminal is located outside the LADN service area, which may be understood as the terminal entering the idle state, and the terminal is located outside the LADN service area; it may also be understood as a short time after the terminal enters the idle state. For example, 1ms, 5ms, the terminal is located outside the LADN service area. For example, when the terminal's RRC connection release is completed, the terminal is located outside the LADN service area, or the terminal is located outside the LADN service area after a short time after the terminal's RRC connection release is completed.

Further, when the terminal enters the idle state, the terminal may determine whether the terminal is outside the LADN service area. It should be noted that the terminal enters the idle state and the terminal determines whether it is located outside the LADN service area, or may have a sequence. Therefore, when the terminal enters the idle state, determining whether the terminal is outside the LADN service area may mean that when the terminal releases the signaling connection with the AN, such as an RRC connection, it is simultaneously determined whether the terminal is outside the LADN service area; or Determining whether the terminal is outside the LADN service area after the terminal releases the signaling connection with the AN, such as an RRC connection; or determining whether the terminal is outside the LADN service area when the terminal converts the connection management status to CM-IDLE Or after the terminal converts the connection management state to CM-IDLE, it is determined whether the terminal is outside the LADN service area. The release of the RRC connection may refer to a shorter time after the completion of the RRC connection release, for example, 1 ms, 5 ms. After the connection management state is converted to CM-IDLE, the connection management state may also be converted to a comparison after the completion of the CM-IDLE. After a short time, for example, 1 ms, 5 ms.

Optionally, when the terminal is located outside the LADN service area, the terminal saves the first information, where the first information includes, when the terminal enters an idle state, the terminal is located outside the LADN service area. When the terminal terminal is located in the LADN service area, the information may not be saved, and the information including the terminal being located in the LADN service area when the terminal enters the idle state may be saved.

When the terminal stores the first information, it may indicate that the terminal is located outside the LADN service area when entering the idle state, that is, the last location of the terminal that is mastered by the network side is outside the LADN service area, so in order to obtain the LADN related service, when When the terminal moves into the LADN service area in the idle state, the registration process or the service request process is triggered.

Optionally, when the terminal enters the idle state, if the terminal determines that the terminal is located outside the LADN service area, the terminal may determine whether to enter the LADN service area, that is, when the terminal enters the idle state, if the terminal determines that the terminal is located in the LADN. Outside the service area, the terminal starts to detect whether it enters the LADN service area.

(2) When the terminal is outside the LADN service area, the terminal enters the connected state.

When the terminal is located outside the LADN service area, it may refer to the duration when the terminal moves out of the LADN service area, or when the terminal moves out of the LADN service area until it moves into the LADN service area again. Further, the terminal moves out of the LADN service area, and the terminal moves within the registration area RA from the LADN service area to the outside of the LADN service area; the terminal enters the connected state, which can be understood as any of the following: when the terminal moves out of the LADN service area, the terminal is connected. The terminal is in an idle state when the terminal moves out of the LADN service area, but enters the connected state after moving out of the LADN service area.

The terminal entering the connected state may refer to that the terminal establishes a NAS signaling connection process with the network side. For example, the terminal and the network side perform a registration request process or a service request process. Therefore, when the terminal is outside the LADN service area, the terminal enters the connection. The state can be understood as the terminal is informed on the information network side outside the LADN service area, so that the SMF may notify the UPF to stop sending the downlink data notification DDN of the PDU session of the LADN to the SMF.

Further, when the terminal is located outside the LADN service area, the terminal may determine whether the connection state has been entered.

Optionally, when the terminal enters the connected state, the terminal saves the second information, where the second information includes the terminal entering the connected state when the terminal is located outside the LADN service area. When the terminal does not enter the connected state, the information may not be saved, and the information may be saved, including when the terminal is outside the LADN service area, and the terminal determines that the connected state has not been entered.

When the terminal saves the second information, it may indicate that the terminal is known on the network side outside the LADN service area, that is, the last location information of the terminal saved on the network side is that the terminal is located outside the LADN service area. Specifically, when the terminal enters the idle state, the terminal determines, according to the second information, that the last location information of the terminal saved by the network side is that the terminal is located outside the LADN service area. Therefore, when the terminal moves into the LADN service area in the idle state, a registration request or a service request is sent to the core network device.

In another embodiment, when the terminal enters the idle state, the terminal may determine that the terminal is located outside the LADN service area according to the target information. For example, when the terminal enters the idle state, the target information may be the second information, the terminal stores the second information, and the terminal determines, according to the second information, that the terminal is located outside the LADN service area.

In another embodiment, when the terminal is in the idle state, the terminal may determine that the terminal enters the connected state when the terminal is located outside the LADN service area according to the target information. For example, when the terminal is in the idle state, the target information may be the second information, and the terminal stores the second information. When the terminal determines, according to the second information, that the terminal is located outside the LADN service area, the terminal enters the connected state.

Optionally, when the terminal saves the second information to enter the idle state, the terminal needs to determine whether to move into the LADN service area, that is, the terminal may start detecting whether to enter the LADN service area.

The detecting, by the terminal, whether the terminal enters the LADN service area includes: the terminal acquires the tracking area identifier TAI; the terminal determines whether the TAI belongs to the LADN service area; when the TAI belongs to the LADN service area, the terminal determines to enter the LADN service area. That is, each time the terminal detects a new TAI, that is, when the TA of the terminal changes, it is determined whether the new TAI belongs to the LADN service area, and if so, it is determined that the terminal enters the LADN service area.

Optionally, when considering the RRC inactive state, the first condition further includes: when the terminal enters RRC inactive, the terminal is located outside the LADN service area. The terminal entering the RRC inactive may be that the terminal suspends the RRC connection, and may also indicate that the RRC connection state of the terminal is changed from the RRC connected connection state to the RRC inactive. Further, when the terminal enters RRC inactive, the terminal needs to determine whether it is outside the LADN service area. Similarly, the terminal enters RRC inactive and determines whether it is located outside the LADN service area, or may have a sequence. Therefore, when the terminal enters RRC inactive, the terminal determines whether the terminal is located outside the LADN service area, and may indicate that when the terminal suspends a signaling connection with the AN, such as an RRC connection, it is simultaneously determined whether the terminal is located outside the LADN service area; Or determining whether the terminal is outside the LADN service area after the terminal suspends the signaling connection with the AN, for example, the RRC connection; or determining whether the terminal is located in the LADN service area when the terminal converts the RRC connection status to the RRC inactive Or; after the terminal converts the RRC connection state to RRC inactive, it is determined whether the terminal is outside the LADN service area. After the RRC connection is suspended, it may refer to a short time after the RRC connection suspension is completed, for example, 1 ms, 5 ms. After the RRC connection state state is converted to CM-IDLE, the connection management state may be converted to CM-IDLE. After a short time, for example 1ms, 5ms.

It should be noted that the sub-items included in the foregoing first conditions are all possible conditions for the terminal to trigger the registration process or the service request process, but the embodiments of the present invention do not limit the sequence between the conditions.

For example, when the terminal enters the idle state, it may first determine whether there is a LADN PDU session. If there is a LADN PDU session, it may continue to determine whether the terminal is outside the LADN service area. If it is outside the LADN service area, and then judge whether the terminal enters the LADN service area, a registration request or a service request is sent when entering the LADN service area.

For another example, when the terminal has a LADN PDU session, the terminal determines whether it is outside the LADN service area when entering the idle state. Otherwise, the terminal does not determine whether it is outside the LADN service area when the terminal enters the idle state. If it is outside the LADN service area, and then judge whether the terminal enters the LADN service area, a registration request or a service request is sent when entering the LADN service area. The PDU session in which the terminal has the LADN may be recorded in the memory by the UE after the PDU session of the LADN is established, and may be a flag bit or a parameter. When the terminal enters the idle state, it determines whether the LADN exists according to the saved information. PDU session.

For example, when the terminal moves out of the LADN service area, the PDU session with or without LADN may be first determined. If there is a PDU session of the LADN, it is determined whether the terminal has entered the connected state when it is outside the LADN service area. If, when the terminal moves out of the LADN service area, the terminal has a LADN PDU session, and when the terminal enters the connected state when the terminal is outside the LADN service area, it may indicate that the core network device knows that the terminal has moved out of the LADN service area, that is, the core. The last location of the terminal mastered by the network device is outside the LADN service area. Therefore, in order to obtain the LADN related service, when the terminal moves into the LADN service area in the idle state, the terminal triggers the registration process or the service request process.

For another example, when the terminal has a LADN PDU session, the terminal judges whether it has entered the connected state when moving out of the LADN service area. Otherwise, the terminal does not judge whether it has entered the connected state when moving out of the LADN service area. If the connection state is entered outside the LADN service area, a registration request or service request is sent when entering the LADN service area. The PDU session in which the terminal has the LADN may be recorded in the memory by the UE after the PDU session of the LADN is established, and may be a flag bit or a parameter. When the terminal enters the idle state, it determines whether the LADN exists according to the saved information. PDU session.

Optionally, if the terminal saves the first information or the second information, when the certain condition is met, the terminal releases the saved first information or the second information.

The terminal enters the connected state, that is, the connection management state of the terminal is converted to CM-CONNECTED;

When the terminal enters the LADN service area; or,

When the terminal receives a Registration Accept message or a Service Accept message.

Optionally, the terminal may determine to move into the LADN service area in an idle state according to the information sent by the core network device, where the terminal sends a registration request or a service request to the core network device. When the terminal is in the connected state, the LADN service area is removed, and the first core network device (such as SMF) releases the user plane connection of the LADN PDU session, and may send a request to the second core network device (such as UPF) to request the second core. The network device (such as the UPF) stops sending the DDN of the session or discards the corresponding downlink data.

Specifically, before the terminal sends the registration request or the service request to the core network device, the method may further include: receiving, by the terminal, the first parameter sent by the first core network device, where the first parameter is used to indicate that the terminal sends the core to the core when the first condition is met. The network device sends a registration request or a service request; or the first parameter is used to notify the terminal that the DDN of the PDU session for accessing the LADN is unavailable.

It should be noted that the first core network device that sends the first parameter to the terminal may be a session management device, such as an SMF, or a mobility management device, such as an AMF, or other core network device. The specific name or type of the core network device and the system to which the core network device belongs are not specifically limited. When the core network device is an SMF, the SMF sends the first parameter to the terminal through the AMF.

It can be understood that the terminal knows that the DDN of the PDU session of the LADN is unavailable, and may refer to that the terminal learns that the core network device stops sending the paging message of the PDU session for the terminal, or the terminal learns that the core network device stops sending the DDN of the PDU session to the SMF. Or the terminal learns that the paging message of the PDU session cannot be received.

It can be understood that the terminal may have multiple PDU sessions of the LADN, and these PDU sessions may belong to the same LADN or may belong to different LADNs. The terminal may determine, according to the information sent by the core network device, which DDNs of the PDU session are not used or which LADN service areas are moved in the idle state, and the registration process or the service request process needs to be triggered. Specifically, the terminal receives the identifier of the PDU session of the LADN sent by the core network device, or the terminal receives the DNN corresponding to the LADN sent by the core network device.

Optionally, after receiving the first parameter sent by the first core network device, the terminal may also release the first parameter when the following condition is met:

After the terminal moves into the LADN service area, the terminal releases the first parameter;

The terminal receives the second parameter sent by the core network device, and the terminal releases the first parameter according to the second parameter; or

After the terminal triggers the registration request process or the service request process, the terminal releases the first parameter.

The second parameter is used to indicate that the terminal releases the first parameter; or the second parameter is used to indicate that the terminal learns that the downlink data of the PDU session accessing the LADN is notified that the DDN is available, thereby releasing the first parameter.

It can be understood that the terminal knows that the DDN of the PDU session of the LADN is available. It can be understood that the terminal learns that the core network sends a paging message of the PDU session to the terminal, or the terminal learns that the UPF sends the DDN of the PDU session to the SMF, or the terminal learns that Received a paging message for the PDU session.

In the embodiment of the present application, the terminal triggering the registration process may include the terminal sending a registration request to the AMF. The registration request may further include one or more of the following: a DNN corresponding to the LADN, the DNN is used to identify the LADN; an identifier of the PDU session, the identifier of the PDU session is used to identify the PDU session of the LADN; or, the indication information, The indication information is used to instruct the terminal to enter the LADN service area.

The terminal triggering the service request process may include the terminal sending a service request to the AMF. The service request includes one or more of the following: a DNN corresponding to the LADN, the DNN is used to identify the LADN; an identifier of the PDU session, the identifier of the PDU session is used to identify the PDU session of the LADN; or, the indication information, the indication The information is used to instruct the terminal to enter the LADN service area.

S320: The network device starts to send the DDN of the PDU session or stops dropping the downlink data.

The network device may include an AMF, an SMF, and an UPF, and the S320 may specifically include:

The third core network device (such as the AMF) receives the registration request or the service request sent by the terminal, where the registration request or the service request includes indication information, where the indication information is used to indicate that the terminal enters the LADN service area;

It should be noted that the registration request or the service request sent by the terminal is forwarded to the AMF by the access node AN, and the AN carries the location information of the terminal when forwarding the message, and the AMF may also determine the location information of the terminal sent by the AN. Whether the terminal enters the LADN service area.

When the AMF determines, according to the location information of the terminal, that the terminal enters the LADN service area, the AMF sends the SMF a notification message that the terminal enters the LADN service area.

After the first core network device (such as the SMF) receives the notification information that the terminal sent by the third core network device (such as the AMF) enters the LADN service area, the first core network device (such as the SMF) notifies the second core network device (such as The first core network device (such as the SMF) notifies the second core network device (such as the UPF) to start sending the DDN of the PDU session or stop discarding the PDU session when the DDN of the PDU session of the LADN is dropped or the downlink data is discarded. Downstream data.

With the embodiment of the present application, the problem that the terminal does not receive the paging message related to the LADN PDU session after the terminal enters the LADN service area in the idle state is solved. When the terminal moves to the LADN service area in the idle state, the LADN service can be continued, which reduces the possibility of data loss and saves signaling resources.

The embodiments of the present application are further described below with reference to specific examples.

FIG. 4 is a schematic diagram of signaling interaction of another mobility management method according to an embodiment of the present disclosure. As shown in FIG. 4, the terminal and the SMF have a LADN PDU session, and the PDU session is in a deactivated state, that is, the user plane connection of the PDU session is released, but other contexts of the PDU session still exist, and the user plane of the PDU session The connection includes a connection between the terminal and the AN and a connection between the AN and the UPF. If there are multiple UPFs, the user plane connection further includes a connection between the UPFs. Correspondingly, deactivating the PDU session can be understood as releasing the PDU session. The process of user plane connection. The method specifically includes:

S401: When the connection management state of the terminal is an idle state, and the terminal moves into the LADN service area from outside the LADN service area, the terminal sends a registration request or a service request to the AMF.

It should be noted that the PDU session is in a deactivated state, which may be a combination of one or more of the following features: the radio resource corresponding to the PDU session is released, for example, the DRB is deleted or the time-frequency resource carrying the PDU session is released; the PDU session The corresponding radio resource is suspended, for example, the DRB is suspended or the time-frequency resource carrying the PDU session is suspended; the N3 bearer corresponding to the PDU session (the user plane connection between the access node AN and the user plane functional entity UPF) is Release or suspend, for example, the AN deletes or suspends the address of the UPF corresponding to the PDU session, the uplink tunnel information, the port number, etc., and the UPF deletes or suspends the address of the AN corresponding to the PDU session, the downlink tunnel information, the port number, and the like; the PDU session The corresponding N9 bearer (if the PDU session has multiple UPF services, the N9 bearer refers to the user plane connection between the UPFs) is released or suspended.

Correspondingly, the PDU session can also be in an active state, that is, the user plane connection of the PDU session is established or activated, and the terminal can directly send and receive data of the PDU session.

It can be understood that the PDU session is in an active or deactivated state only to represent that the PDU session has some features described above at certain moments. The embodiment of the present application does not force the terminal to have a state machine to record that the PDU session is active or go. The state of activation.

Optionally, before performing S401, the terminal further needs to meet at least one of the following conditions, where one or more of the following may be determined according to information saved by the terminal:

After the terminal deactivates the PDU session of the LADN, the connection management state of the terminal is a connected state;

After the terminal deactivates the PDU session of the LADN, the connection management state of the terminal is a connected state, and the terminal is located outside the LADN service area;

It should be noted that, after the terminal deactivates the PDU session of the LADN, the connection management state of the terminal is the connected state, which can be understood as a short time after the operation of the user plane connection of the terminal releasing the PDU session is completed, and the connection management state of the terminal is connected. State, that is, the terminal does not perform deactivation of the PDU session because it is going to enter the idle state, but may be deactivated due to the LADN PDU session performed after the terminal moves out of the LADN service area, in this case, the terminal location saved by the network side The information is that the terminal is outside the LADN service area, so the SMF may notify the UPF to stop the DDN of the LADN PDU session.

When the terminal enters the idle state, it is outside the LADN service area;

The operation of deactivating the user plane connection of the LADN session is not performed when the terminal enters the idle state;

When the terminal enters the idle state, the operation of deactivating the user plane connection of the LADN session is not performed, and the terminal is located outside the LADN service area.

It should be noted that the operation of the user plane connection that does not perform the deactivation of the LADN session when the terminal enters the idle state may be understood as the user plane connection that does not perform the deactivation LADN session in the process of releasing the NAS signaling connection, that is, the user of the LADN session. The connection is deactivated before the release of the NAS signaling connection. The reason may be the deactivation of the LADN PDU session performed after the terminal moves out of the LADN service area. In this case, the terminal location information stored on the network side is the terminal located. Outside the LADN service area, the SMF may notify the UPF to stop the DDN of the LADN PDU session. When the terminal deactivates the user plane connection of the LADN PDU session, the connection management state of the terminal is determined and saved as the first information, and the connection management state of the PDU session in which the terminal deactivates the LADN is determined to be the connected state according to the first information.

When the terminal deactivates the user plane connection of the LADN PDU session, it determines the connection management status of the terminal and whether the terminal is located in the LADN service area and saves the second information. The connection management state of the PDU session in which the terminal deactivates the LADN may be determined according to the second information to be a connected state, and the terminal is located outside the LADN service area.

Optionally, when the terminal enters the connected state or the LADN PDU session is activated, the saved first information or the second information is released.

It should be noted that when the terminal deactivates the user plane connection of the LADN PDU session, determining the connection management status of the terminal may be understood as one or more of the following:

When the operation of the user plane connection of the terminal release PDU session is completed, the connection management state of the terminal is in a connected state or an idle state;

A short time after the user plane connection of the terminal release PDU session is completed, whether the connection management state of the terminal is in a connected state or an idle state, to ensure that the user plane of the PDU session is released by the terminal because the terminal transitions from the connected state to the idle state. The terminal's connection management state machine has sufficient time to transition to the idle state.

When the terminal enters the idle state, it is determined whether it is outside the LADN service area and saved as the third information. According to the third information, it may be determined that the terminal is outside the LADN service area when entering the idle state.

Optionally, when the terminal enters the connected state again, the saved third information is released.

When the terminal enters the idle state, it is determined whether the operation of deactivating the user plane connection of the LADN session is performed, and is saved as the fourth information; and determining, according to the fourth information, that the terminal does not perform the deactivation of the user plane connection of the LADN session when the terminal enters the idle state. operating.

When the terminal enters the idle state, it is determined whether the operation of deactivating the user plane connection of the LADN session and whether the terminal is located in the LADN service area is performed and saved as the fifth information. The operation of deactivating the user plane connection of the LADN session when the terminal enters the idle state may be determined according to the fifth information, and the terminal is located outside the LADN service area.

Optionally, the saved fourth information or the fifth information is released when the terminal enters the connected state.

Optionally, when the terminal enters an idle state, the terminal may determine, according to the target information, that the terminal is located outside the LADN service area. For example, when the terminal enters the idle state, the target information may be the second information or the fifth information, the terminal stores the second information or the fifth information, and the terminal determines, according to the second information or the fifth information, that the terminal is located outside the LADN service area.

S402. The AMF determines that the terminal moves into the LADN service area.

The AMF may determine that the terminal moves into the LADN service area according to the registration request sent by the terminal or the indication in the service request.

The AMF may also determine the current location of the terminal after receiving the registration request or the service request sent by the terminal, and determine whether the terminal moves into the LADN service area.

S403. The AMF sends a notification message to the SMF. The notification information is used to indicate that the terminal moves into the LADN service area.

The AMF can also send a registration accept message or a service accept message to the terminal.

S404. The SMF modifies the PDU session of the LADN.

The SMF modifies the PDU session of the LADN when the user plane connection of the PDU session is determined to be in a deactivated state.

For example, the SMF determines that the UPF has been notified to stop sending the DDN of the LADN session or discarding the downlink data. Then, the SMF sends a session modification request to the UPF, where the session modification request is used to instruct the UPF to perform one or more of the following: sending the DDN of the PDU session to the SMF, or stopping the downlink data of the PDU session.

The UPF performs the corresponding operations according to the instructions of the SMF. For example, one or more of the following are performed: the DDN of the PDU session is sent to the SMF, or the downlink data of the PDU session is stopped.

The embodiment of the present application can implement that when the terminal is in an idle state, after re-entering the LADN service area, the DDN and the downlink data can be re-received, thereby reducing data loss.

FIG. 5 is a schematic diagram of signaling interaction of another mobility management method according to an embodiment of the present disclosure. As shown in FIG. 5, the method specifically includes:

S501. The SMF sends a first request to the UPF, where the first request is used to request the UPF to stop sending the DDN corresponding to the LADN PDU session.

S502. The SMF sends the first parameter to the terminal. The first parameter is used when the terminal determines that the condition is met, triggering the registration request process or the service request process; or the first parameter is used by the terminal to learn that the DDN of the PDU session accessing the LADN is unavailable. For example, the SMF may carry the first parameter terminal in the NAS SM message, the N1 SM information or the N1 SM container, and the first parameter may include at least one of the following sub-parameters: LADN DNN (or PDU session) ID), DDN unavailability indication, cause value, timer, LADN DNN (or PDU session ID) and DDN unavailability indication are used to indicate that the network stops delivering the PDU session (or PDU session) corresponding to the LADN DNN. The DDN of the PDU session to which the ID corresponds. The reason is that the terminal moves out of the LADN service area, and the timer indicates the length of time that the DDN is stopped.

It should be noted that the first parameter may be sent by the SMF to the terminal via the AMF. Specifically, the SMF may be in the registration request process (Service Request), the service request process (Service Request), and the user plane deactivation process of the PDU session (CN- The PDU Session Modification is sent to the terminal via the SMF.

If the SMF in the service request process determines that the terminal stops the DDN of the PDU session of the LADN after the terminal moves out of the LADN service area, the NAS message carrying the first parameter, the N1 SM information or the N1 SM container may be encapsulated by the AMF. The information is sent to the terminal in the service accepting message, and may be sent to the terminal by the AMF to be sent to other NAS messages. The specific NAS message name is not limited in this embodiment.

The SMF notifies the UPF to stop delivering the LADN PDU if the process of deactivating the PDU session of the LADN, for example, the process of initiating the deactivation of the existing PDU session (CN-initiated deactivation of the existing PDU session) The DDN of the session carries the NAS SM message of the first parameter, and the N1 SM information or the N1 SM container is sent by the SMF to the AMF in the deactivation process of the PDU session, and then encapsulated by the AMF into the NAS message and sent to the terminal, and the application is implemented. For example, the specific NAS message name is not limited.

Or, if the SMF notifies the UPF to stop the DDN of the PDU session of the LADN, the SMF triggers the PDU session modification process, in the process of deactivating the LADN PDU session, for example, the CN-initiated deactivation of the UP connection of an existing PDU session. The PDU session modification process carries the NAS SM message of the first parameter, and the N1 SM information or the N1 SM container is sent to the AMF, and then encapsulated into the NAS message by the AMF and sent to the terminal. The embodiment of the present application does not perform the specific NAS message name. limited. S503. The terminal saves the first parameter, and when the one of the following conditions is met, the terminal releases the first parameter.

The terminal enters the LADN service area;

The timer expires;

Receiving, by the terminal, a parameter or an indication sent by the core network device to release the first parameter;

When the terminal triggers the registration request process or the service request process, when the registration accept message or the service accept message is received.

S504. The connection management state of the terminal is changed from a connected state (CM-CONNECTED) to an idle state (CM-IDLE).

S505: When the terminal is in the idle state and moves into the LADN service area, if the first parameter is saved, it is determined to trigger the registration process or trigger the service request process.

S506. The terminal sends a registration request (or a service request).

Optionally, the registration request (or service request) carries an LADN DNN, and the terminal moves to the LADN service area.

S507. The network side determines that the terminal starts to normally send the DDN after entering the LADN service area.

S508. The SMF sends a second parameter to the terminal, where the second parameter may be used to indicate that the DDN of the PDU session accessing the LADN is available.

S509. The AMF sends a registration accept message to the terminal.

S510. The terminal releases the first parameter or saves the second parameter.

FIG. 6 is a schematic structural diagram of a terminal according to an embodiment of the present application. As shown in FIG. 6, the terminal 600 includes a transmitting unit 601. It may further include a determining unit 602, a saving unit 603, and a releasing unit 604. The terminal has a PDU session of the LADN, and the terminal 600 specifically includes:

The sending unit 601 is configured to send a registration request or a service request to the core network device when the first condition is met; wherein the first condition includes the terminal moving into the LADN service area in an idle state.

Optionally, the first condition further includes:

When the terminal enters the idle state, the terminal is located outside the LADN service area; or,

When the terminal is outside the LADN service area, the terminal enters the connected state.

Optionally, it also includes:

The determining unit 602 is configured to determine whether the terminal is outside the LADN service area when the terminal enters an idle state.

Optionally, the determining unit 602 is further configured to determine whether to move into the LADN service area when the terminal is located outside the LADN service area.

Optionally, the determining unit 602 is further configured to: determine, when the terminal is located outside the LADN service area, whether the terminal enters a connected state;

The saving unit 603 is configured to save the target information when the terminal enters the connected state, and the target information includes that the terminal enters the connected state when the terminal is outside the LADN service area.

Optionally, the determining unit 602 is further configured to: when the terminal enters the idle state, determine, according to the target information, that the terminal is located outside the LADN service area.

Optionally, further comprising

The release unit 604 is configured to release the target information when the terminal enters the connected state or the terminal enters the LADN service area.

Optionally, the determining unit 602 is specifically configured to:

Obtaining the tracking area identifier TAI;

When the TAI belongs to the LADN service area, it is determined to move into the LADN service area.

Optionally, it also includes:

a receiving unit, configured to receive a first parameter sent by the core network device, where the first parameter is used to indicate that the terminal sends a registration request or a service request to the core network device when the first condition is met; or the first parameter is used to notify the terminal to connect The downstream data of the PDU session into the LADN informs the DDN that it is unavailable.

Optionally, the first parameter includes at least one of the following:

ID of the LADN PDU session;

The data network name DNN corresponding to LADN; or,

The indication information is used to indicate that the downlink data notification DDN is unavailable.

Optionally, it also includes:

a releasing unit 604, configured to: after the terminal moves into the LADN service area, the terminal releases the first parameter;

or,

The receiving unit is further configured to receive the second parameter sent by the core network device.

a releasing unit 604, configured to release the first parameter according to the second parameter;

or,

The releasing unit 604 is configured to release the first parameter after the terminal sends the registration request or the service request to the core network device.

The terminal 600 can function as a terminal of the mobility management method as described in FIGS. 3 to 5, and performs the steps performed by the terminal in FIGS. 3 to 5. The problem that the terminal does not receive the paging message related to the LADN PDU session after the terminal enters the LADN service area in the idle state is solved. When the terminal moves to the LADN service area in the idle state, the LADN service can be continued, which reduces the possibility of data loss and saves signaling resources.

FIG. 7 is a schematic structural diagram of a core network device according to an embodiment of the present application. As shown in FIG. 7, the core network device 700 includes a receiving unit 702 and a transmitting unit 701. The core network device 700 is applicable to the first core network device, and the core network device 700 has a PDU session of the LADN. The core network device 700 includes:

The sending unit 701 is configured to send a first request to the second core network device, where the first request is used to request the second core network device not to send the downlink data notification DDN of the PDU session to the first core network device;

The sending unit 702 is further configured to send, to the terminal, a first parameter, where the first parameter is used to send the registration request or the service request to the first core network device when the terminal determines that the first condition is met, where the first condition includes that the terminal is idle. Move to the LADN service area; or, the first parameter is used to notify the terminal that the DDN of the PDU session is unavailable.

The receiving unit is configured to receive a registration request or a service request sent by the terminal.

Optionally, the first parameter includes at least one of the following:

ID of the LADN PDU session; or,

The data network name DNN corresponding to LADN;

Optionally, the sending unit 701 is further configured to: send, to the terminal, a second parameter, where the second parameter is used to indicate that the terminal releases the first parameter; or the second parameter is used to notify the downlink data of the terminal PDU session that the DDN is available.

The core network device 700 can serve as a core network device of the mobility management method as described in FIGS. 3 to 5, and performs the steps performed by the core network device in FIGS. 3 to 5. The problem that the terminal does not receive the paging message related to the LADN PDU session after the terminal enters the LADN service area in the idle state is solved. When the terminal moves to the LADN service area in the idle state, the LADN service can be continued, which reduces the possibility of data loss and saves signaling resources.

FIG. 8 is a schematic structural diagram of another terminal according to an embodiment of the present application. As shown in FIG. 8, the terminal 800 includes a transceiver 801 for communicating with a core network device, a processor 802 for storing a program, and a processor 802 for executing The program stored by the memory to perform the steps performed by the terminal in Figures 3-5 above.

The terminal 800 has a PDU session of the LADN, and the terminal 800 specifically includes:

The transceiver 801 is configured to send a registration request or a service request to the core network device when the first condition is met; wherein the first condition includes the terminal moving into the LADN service area in an idle state.

Optionally, the first condition further includes:

Optionally, it also includes:

The processor 802 is configured to determine whether the terminal is outside the LADN service area when the terminal enters an idle state.

Optionally, the processor 802 is further configured to determine whether to move into the LADN service area when the terminal is located outside the LADN service area.

Optionally, the processor 802 is further configured to: determine, when the terminal is located outside the LADN service area, whether the terminal enters a connected state;

The memory 603 is configured to save the target information when the terminal enters the connected state, and the target information includes the terminal entering the connected state when the terminal is located outside the LADN service area.

Optionally, the processor 802 is further configured to: when the terminal enters an idle state, determine, according to the target information, that the terminal is located outside the LADN service area.

Optionally, the processor 802 is configured to release the target information when the terminal enters the connected state or the terminal enters the LADN service area.

Optionally, the processor 802 is specifically configured to:

Obtaining the tracking area identifier TAI;

Optionally, the transceiver 801 is configured to receive a first parameter sent by the core network device, where the first parameter is used to indicate that the terminal sends a registration request or a service request to the core network device when the first condition is met; or, the first parameter The downlink data notification DDN for notifying the terminal to access the LADN PDU session is not available.

Optionally, the first parameter includes at least one of the following:

ID of the LADN PDU session;

The data network name DNN corresponding to LADN; or,

Optionally, the processor 802 is configured to: after the terminal moves into the LADN service area, the terminal releases the first parameter;

or,

The transceiver 801 is further configured to receive a second parameter sent by the core network device.

The processor 802 is configured to release the first parameter according to the second parameter;

or,

The processor 802 is configured to release the first parameter after the terminal sends a registration request or a service request to the core network device.

The terminal 800 can serve as a terminal of the mobility management method as described in FIGS. 3 to 5, and performs the steps performed by the terminal in FIGS. 3 to 5. The problem that the terminal does not receive the paging message related to the LADN PDU session after the terminal enters the LADN service area in the idle state is solved. When the terminal moves to the LADN service area in the idle state, the LADN service can be continued, which reduces the possibility of data loss and saves signaling resources.

FIG. 9 is a schematic structural diagram of another core network device according to an embodiment of the present application. As shown in FIG. 9, the core network device 900 includes a transceiver 901, a processor 902, and a memory 903. The transceiver 901 is configured to communicate with other core network devices or terminals; the memory 903 is configured to store a program; The program 902 is configured to execute the program stored by the memory to perform the steps performed by the core network device in the foregoing FIG. 3-5.

The core network device 900 is applicable to the first core network device, and the core network device 900 has a PDU session of the LADN. The core network device 900 includes:

The transceiver 901 is configured to send a first request to the second core network device, where the first request is used to request the second core network device not to send the downlink data notification DDN of the PDU session to the first core network device;

The transceiver 901 is further configured to: send, to the terminal, a first parameter, where the first parameter is used to send the registration request or the service request to the first core network device when the terminal determines that the first condition is met, where the first condition includes that the terminal is idle. Move to the LADN service area; or, the first parameter is used to notify the terminal that the DDN of the PDU session is unavailable.

The transceiver 901 is configured to receive a registration request or a service request sent by the terminal.

Optionally, the first parameter includes at least one of the following:

ID of the LADN PDU session; or,

The data network name DNN corresponding to LADN;

Optionally, the transceiver 901 is further configured to: send, to the terminal, a second parameter, where the second parameter is used to indicate that the terminal releases the first parameter; or the second parameter is used to notify the downlink data of the terminal PDU session that the DDN is available.

The core network device 900 can serve as a core network device of the mobility management method as described in FIGS. 3 through 5, and performs the steps performed by the core network device in FIGS. 3 through 5. The problem that the terminal does not receive the paging message related to the LADN PDU session after the terminal enters the LADN service area in the idle state is solved. When the terminal moves to the LADN service area in the idle state, the LADN service can be continued, which reduces the possibility of data loss and saves signaling resources.

Embodiments of the present application provide a computer program product comprising instructions that, when executed on a computer, perform the methods/steps of Figures 3 through 5 above.

The embodiment of the present application provides a computer readable storage medium for storing instructions, when the instructions are executed on a computer, performing the methods/steps in FIG. 3 to FIG. 5 above.

The embodiment of the present application provides a communication system. The system includes any one or more of the above-described embodiments described in connection with Figures 3 through 5.

In each of the above embodiments of the present application, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, it 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 processes or functions described in accordance with embodiments of the present application are generated in whole or in part. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer readable storage medium or transferred from one computer readable medium to another computer readable medium, for example, the computer instructions can be wired from a website site, computer, server or data center (for example, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (eg infrared, wireless, microwave, etc.) to another website site, computer, server or data center. The computer readable storage medium can be any available media that can be accessed by a computer or a data storage device such as a server, data center, or the like that includes one or more available media. The usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state hard disk) or the like.

The above description is only a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed in the present application. Replacement should be covered by the scope of this application. Therefore, the scope of protection of the present application should be determined by the scope of protection of the claims.

Claims

A method for mobility management, characterized by a terminal for a protocol data unit PDU session in which a local area data network LADN exists, the method comprising:

When the first condition is met, the terminal sends a registration request or a service request to the core network device; wherein the first condition includes that the terminal moves into the LADN service area in an idle state.
The method of claim 1, wherein the first condition further comprises:

When the terminal enters an idle state, the terminal is located outside the LADN service area; or,

When the terminal is outside the LADN service area, the terminal enters an over-connected state.
The method according to claim 1 or 2, wherein before the terminal sends a registration request or a service request to the core network device, the method further includes:

When the terminal enters an idle state, the terminal determines whether the terminal is located outside the LADN service area.
The method of claim 3, further comprising:

When the terminal is outside the LADN service area, the terminal determines whether to move into the LADN service area.
The method according to claim 1 or 2, wherein before the terminal sends a registration request or a service request to the core network device, the method further includes:

When the terminal is located outside the LADN service area, the terminal determines whether the terminal enters an over-connected state;

When the terminal enters the connected state, the terminal saves the target information, and the target information includes the terminal entering the connected state when the terminal is located outside the LADN service area.
The method of claim 5, further comprising:

When the terminal enters an idle state, the terminal determines, according to the target information, that the terminal is located outside the LADN service area.
The method of claim 6 further comprising:

When the terminal is outside the LADN service area, the terminal determines whether to move into the LADN service area.
A method according to any one of claims 5-7, further comprising

The terminal releases the target information when the terminal enters a connected state or the terminal enters the LADN service area.
The method according to any one of claims 4, 7 or 8, wherein the determining, by the terminal, whether to move into the LADN service area comprises:

The terminal acquires a tracking area identifier TAI;

When the TAI belongs to the LADN service area, the terminal determines to move into the LADN service area.
The method according to any one of claims 1 to 9, wherein before the terminal sends a registration request or a service request to the core network device, the method further includes:

Receiving, by the terminal, the first parameter sent by the core network device, where the first parameter is used to indicate that the terminal sends a registration request or a service request to the core network device when the first condition is met; or The first parameter is used to notify the terminal that the downlink data of the PDU session of the LADN is notified that the DDN is unavailable.
The method of claim 10 wherein said first parameter comprises at least one of:

The identifier of the PDU session of the LADN;

The data network name DNN corresponding to the LADN; or

The indication information is used to indicate that the DDN is unavailable.
The method according to claim 10 or 11, wherein after receiving the first parameter sent by the core network device, the terminal further includes any one of the following:

After the terminal moves into the LADN service area, the terminal releases the first parameter;

The terminal receives the second parameter sent by the core network device, and the terminal releases the first parameter according to the second parameter; or

After the terminal sends a registration request or a service request to the core network device, the terminal releases the first parameter.
A method for mobility management, characterized by a first core network device for a protocol data unit PDU session of a local area data network (LADN), the method comprising:

The first core network device sends a first request to the second core network device, where the first request is used to request the second core network device not to send the downlink data notification DDN of the PDU session to the first core network device;

The first core network device sends a first parameter to the terminal, where the first parameter is used to indicate that the terminal sends a registration request or a service request to the first core network device when the first condition is met; The first condition includes that the terminal moves to the LADN service area in an idle state; or the first parameter is used to notify the terminal that the DDN of the PDU session is unavailable.
The method of claim 13 wherein said first parameter comprises at least one of the following:

An identifier of a PDU session accessing the LADN;

The data network name DNN corresponding to the LADN; or

The indication information is used to indicate that the downlink data notification DDN is unavailable.
The method according to claim 13 or 14, wherein after the first core network device sends the first parameter to the terminal, the method further includes:

The first core network device sends a second parameter to the terminal, where the second parameter is used to indicate that the terminal releases the first parameter; or the second parameter is used to notify the terminal that the PDU is The downstream data of the session informs the DDN that it is available.
A terminal, characterized by a terminal for a protocol data unit PDU session of a local area data network LADN, the terminal comprising:

And sending, by the sending unit, a registration request or a service request to the core network device when the first condition is met; wherein the first condition includes that the terminal moves into the LADN service area in an idle state.
The terminal according to claim 16, wherein the first condition further comprises:

When the terminal enters an idle state, the terminal is located outside the LADN service area; or,

When the terminal is outside the LADN service area, the terminal enters an over-connected state.
The terminal according to claim 16 or 17, further comprising:

The determining unit is configured to determine whether the terminal is located outside the LADN service area when the terminal enters an idle state.
The terminal according to claim 18, wherein the determining unit is further configured to determine whether to move into the LADN service area when the terminal is located outside the LADN service area.
The terminal according to claim 16 or 17, further comprising:

The determining unit is further configured to: when the terminal is located outside the LADN service area, determine whether the terminal enters a connected state;

And a saving unit, configured to save target information when the terminal enters a connected state, where the target information includes, when the terminal is located outside the LADN service area, the terminal enters a connected state.
The terminal according to claim 20, wherein the determining unit is further configured to: when the terminal enters an idle state, determine, according to the target information, that the terminal is located outside the LADN service area.
The terminal according to claim 21, wherein the determining unit is further configured to determine whether to move into the LADN service area when the terminal is located outside the LADN service area.
A terminal according to any one of claims 20-22, further comprising

And a releasing unit, configured to release the target information when the terminal enters a connected state or the terminal enters the LADN service area.
The terminal according to any one of claims 19, 22 or 23, wherein the determining unit is specifically configured to:

Obtaining the tracking area identifier TAI;

When the TAI belongs to the LADN service area, it is determined to move into the LADN service area.
The terminal according to any one of claims 16 to 24, further comprising:

a receiving unit, configured to receive a first parameter sent by the core network device, where the first parameter is used to indicate that the terminal sends a registration request or a service request to the core network device when the first condition is met; Alternatively, the first parameter is used to notify the terminal that the downlink data of the PDU session of the LADN is notified that the DDN is unavailable.
The terminal according to claim 25, wherein said first parameter comprises at least one of the following:

The identifier of the PDU session of the LADN;

The data network name DNN corresponding to the LADN; or

The indication information is used to indicate that the DDN is unavailable.
The terminal according to claim 25 or 26, further comprising:

a releasing unit, configured to release the first parameter after the terminal moves into the LADN service area; or

The receiving unit is further configured to receive a second parameter that is sent by the core network device, and a release unit, configured to release the first parameter according to the second parameter; or

The releasing unit is configured to release the first parameter after the terminal sends a registration request or a service request to the core network device.
A core network device, wherein the first core network device for the protocol data unit PDU session of the local area data network (LADN) includes:

a sending unit, configured to send a first request to the second core network device, where the first request is used to request the second core network device not to send the downlink data notification DDN of the PDU session to the first core network device;

The sending unit is further configured to send a first parameter to the terminal, where the first parameter is used to indicate that the terminal sends a registration request or a service request to the first core network device when the first condition is met; The first condition includes that the terminal moves to the LADN service area in an idle state; or the first parameter is used to notify the terminal that the DDN of the PDU session is unavailable.
The core network device according to claim 28, wherein the first parameter comprises at least one of the following:

An identifier of a PDU session accessing the LADN;

The data network name DNN corresponding to the LADN; or

The indication information is used to indicate that the downlink data notification DDN is unavailable.
The core network device according to claim 28 or 29, wherein the sending unit is further configured to send a second parameter to the terminal, where the second parameter is used to instruct the terminal to release the first The parameter is used to notify the terminal that the downlink data of the PDU session is notified that the DDN is available.
A terminal, comprising: a transceiver, a processor and a memory, the transceiver for communicating with a core network device; the memory for storing a program; the processor for executing the program stored by the memory, To perform the method of any of claims 1-12.
A core network device, comprising: a transceiver, a processor and a memory, the transceiver for communicating with other core network devices or terminals; the memory for storing a program; the processor for executing the memory storage Said procedure for performing the method of any of claims 13-15.
A computer readable storage medium comprising computer readable instructions which, when read and executed by a computer, cause the computer to perform the method of any of claims 1-15.
A computer program product comprising computer readable instructions which, when read and executed by a computer, cause a computer to perform the method of any of claims 1-15.
A communication system, comprising: the terminal of claim 31 and the core network device of claim 32.