Context maintaining method and apparatus for user terminal, storage medium, and electronic device

Abstract

The present disclosure relates to a context keeping method and device of a user terminal, a storage medium and an electronic device, and relates to the technical field of communication. The method comprises: receiving a deregistration request sent by a user terminal, obtaining a context valid time according to a first deregistration timer included in the deregistration request and a preset second deregistration timer; generating a deregistration success message according to the context valid time and a context keeping success message, and sending the deregistration success message to the user terminal; keeping the context of the user terminal within the context valid time, and receiving a re-registration request sent by the user terminal when a system update task is executed; canceling the keeping of the context according to a context keeping off indication included in the re-registration request, and generating a re-registration success message according to a context keeping cancellation success message. The present disclosure improves the network access efficiency of the user terminal.

Description

Technical Field

[0001] This disclosure relates to the field of communication technology, and more specifically, to a context-keeping method for a user terminal, a context-keeping device for a user terminal, a computer-readable storage medium, and an electronic device. Background Technology

[0002] In existing mobile communication networks, when a user terminal performs a system update task, it will briefly disconnect from the network. At the same time, since the system update task is automatically triggered by the user terminal, neither the network side nor the application side is aware of it. Therefore, when the user terminal initiates the deregistration process while performing a system update task, it will cause the network side to delete the terminal context of the user terminal during the system update task. Consequently, when the user terminal initiates the re-registration process after the system update task is completed, it needs to rebuild the context, resulting in low network access efficiency for the user terminal.

[0003] It should be noted that the information in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this disclosure is to provide a context-keeping method for a user terminal, a context-keeping device for a user terminal, a computer-readable storage medium, and an electronic device, thereby overcoming, at least to some extent, the problem of low network access efficiency of user terminals caused by limitations and defects in related technologies.

[0005] According to one aspect of this disclosure, a context-preservation method for a user terminal is provided, comprising:

[0006] Receive a deregistration request sent by a user terminal, and obtain the context validity time based on the first deregistration timer and the preset second deregistration timer included in the deregistration request;

[0007] Based on the context validity period and the context retention success message, a deregistration success message is generated and sent to the user terminal;

[0008] The context of the user terminal is maintained within the context validity period, and a re-registration request is received from the user terminal when the system update task is completed.

[0009] The context retention is canceled according to the context retention disable instruction included in the re-registration request, and a re-registration success message is generated according to the message that the context retention was successfully canceled, so as to send the re-registration success message to the user terminal.

[0010] In one exemplary embodiment of this disclosure, a deregistration request sent by a user terminal is received, and the context validity time is obtained based on a first deregistration timer and a preset second deregistration timer included in the deregistration request, including:

[0011] The Access and Mobility Management Function (AMF) receives the deregistration request sent by the user terminal and parses the deregistration request to obtain the first deregistration timer included in the deregistration request, as well as the reason value of the system update task that the user terminal needs to perform.

[0012] The AMF determines the preset second deregistration timer based on the cause value of the system update task, compares the first deregistration timer and the second deregistration timer, and obtains the context validity time based on the comparison result;

[0013] Wherein, if the duration of the first deregistration timer is greater than the duration of the second deregistration timer, then the second deregistration timer is used as the context valid time; if the duration of the first deregistration timer is less than the duration of the second deregistration timer, then the first deregistration timer is used as the context valid time.

[0014] In one exemplary embodiment of this disclosure, generating a deregistration success message based on the context validity period and the context retention success message includes:

[0015] The AMF generates a first session management modification request based on the user terminal's terminal identifier, context persistence enable instruction, context validity period, and the reason value of the system update task, and sends the first session management modification request to the session management function entity SMF;

[0016] The SMF generates a first N4 session modification request based on the context persistence enable instruction included in the first session management modification request and the N4 session identifier corresponding to the user terminal, and sends the first N4 session modification request to the User Plane Function Entity (UPF).

[0017] In response to the first N4 session modification request, the UPF sends a first response message indicating context retention success to the SMF. The SMF generates a second response message based on the context retention success message included in the first response message and sends the second response message to the AMF.

[0018] The AMF generates a random number corresponding to the user terminal, and generates a registration success message based on the random number, the second response message, and the context validity period.

[0019] In one exemplary embodiment of this disclosure, the context of the user terminal includes at least one of a mobility management context, a session management context, and an N4 session context;

[0020] The maintenance of the user terminal's context during the context's validity period includes:

[0021] Maintain the N4 session context corresponding to the first N4 session modification request, and time the retention period of the N4 session context; and / or

[0022] Maintain the session management context corresponding to the user terminal, and time the retention period of the session management context; and / or

[0023] Maintain the mobility management context corresponding to the user terminal and time the duration of the mobility management context maintenance.

[0024] In one exemplary embodiment of this disclosure, the context persistence method for the user terminal further includes:

[0025] Downlink user data for the protocol data unit session associated with the first N4 session modification request is cached.

[0026] In one exemplary embodiment of this disclosure, the context persistence method for the user terminal further includes:

[0027] Determine whether the first timing duration of the session management context is greater than the context validity period;

[0028] If the first timing duration is longer than the context validity period, the maintained session management context is deleted and the maintenance of the session management context is stopped.

[0029] Generate an N4 session context deletion request and send the N4 session context deletion request to the UPF.

[0030] In one exemplary embodiment of this disclosure, the context persistence method for the user terminal further includes:

[0031] In response to the session context deletion request, the UPF releases the N4 session context that has been maintained and corresponds to the first N4 session modification request, and clears the cached downlink user data.

[0032] In one exemplary embodiment of this disclosure, after receiving a re-registration request sent by the user terminal upon completion of a system update task, the context maintenance method of the user terminal further includes:

[0033] The re-registration request is parsed to obtain the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information included in the re-registration request;

[0034] The legitimacy of the user terminal is determined based on the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information.

[0035] In one exemplary embodiment of this disclosure, the retention of the context is cancelled according to the context retention closure indication included in the re-registration request, and a re-registration success message is generated according to the message indicating successful cancellation of context retention, including:

[0036] AMF generates a second session management modification request based on the 5G globally unique temporary identifier and the context preservation off instruction, and sends the second session management modification request to the session management function entity SMF;

[0037] In response to the second session management modification request, the SMF cancels the retention of the session management context corresponding to the user terminal and stops counting down the retention time of the session management context;

[0038] The SMF generates a second N4 session modification request based on the context retention off indication included in the second session management modification request and the N4 session identifier corresponding to the user terminal, and sends the second N4 session modification request to the User Plane Function Entity (UPF).

[0039] In response to the second N4 session modification request, the UPF sends the cached downlink user data of the Protocol Data Unit session associated with the first N4 session modification request to the user terminal, and cancels the maintenance of the N4 session context corresponding to the first N4 session modification request.

[0040] The UPF generates a third response message based on the message indicating that the context preservation was successfully cancelled, and sends the third response message to the SMF.

[0041] The SMF generates a fourth response message based on the message indicating successful cancellation of context preservation included in the third response message, and sends the fourth response message to the AMF;

[0042] The AMF generates a re-registration success message based on the context retention indication cancellation success message included in the fourth response message, and cancels the retention of the mobility management context corresponding to the user terminal, and stops timing the retention time of the mobility management context.

[0043] In one exemplary embodiment of this disclosure, the system update task includes at least one of modem silent reset update, security patch update, operating system update, and modem software update.

[0044] According to one aspect of this disclosure, a context-keeping device for a user terminal is provided, comprising:

[0045] The context validity time calculation module is used to receive a deregistration request sent by the user terminal and obtain the context validity time based on the first deregistration timer and the preset second deregistration timer included in the deregistration request.

[0046] The registration success message generation module is used to generate a registration success message based on the context validity period and the context retention success message, and send the registration success message to the user terminal.

[0047] The context persistence module is used to persist the context of the user terminal during the context validity period and to receive the re-registration request sent by the user terminal when the system update task is completed.

[0048] The re-registration success message generation module is used to cancel the retention of the context according to the context retention shutdown indication included in the re-registration request, and generate a re-registration success message according to the message of successful cancellation of context retention, so as to send the re-registration success message to the user terminal.

[0049] According to one aspect of this disclosure, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the context-keeping method for a user terminal as described in any of the preceding claims.

[0050] According to one aspect of this disclosure, an electronic device is provided, comprising:

[0051] Processor; and

[0052] Memory for storing the executable instructions of the processor;

[0053] The processor is configured to execute the context preservation method of any of the above-described user terminals by executing the executable instructions.

[0054] This disclosure provides a context retention method for a user terminal. On one hand, it receives a deregistration request from the user terminal, obtains the context validity period based on a first deregistration timer and a preset second deregistration timer included in the request, generates a deregistration success message based on the context validity period and a context retention success message, and sends the deregistration success message to the user terminal. Then, it retains the user terminal's context within the context validity period and receives a re-registration request sent by the user terminal upon completion of a system update task. Finally, it cancels context retention based on a context retention shutdown indication included in the re-registration request and generates a re-registration success message based on the context retention cancellation success message. This allows the user terminal to directly use the context saved by the network side within the context validity period without needing to re-establish the context on the network side after completing a system update task, thereby improving the user terminal's network access efficiency. On the other hand, by retaining the user terminal's context within the context validity period during system update tasks, it avoids the problem of heavy network load caused by needing to recreate the context when the user terminal initiates a re-registration request.

[0055] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0056] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0057] Figure 1 The flowchart illustrates a context-keeping method for a mobile terminal according to an example embodiment of the present disclosure.

[0058] Figure 2 An example diagram illustrating a 5G architecture according to an exemplary embodiment of the present disclosure is shown schematically.

[0059] Figure 3 An example diagram of a communication system according to an exemplary embodiment of the present disclosure is shown schematically.

[0060] Figure 4 The diagram schematically illustrates an example structure of a mobile network according to an exemplary embodiment of the present disclosure.

[0061] Figure 5The flowchart illustrates a method for generating a deregistration success message based on a context validity period and a context retention success message, according to an example embodiment of the present disclosure.

[0062] Figure 6 The flowchart illustrates a context-keeping method for a user terminal based on multi-terminal interaction according to an example embodiment of the present disclosure.

[0063] Figure 7 The diagram schematically illustrates a context-keeping device for a mobile terminal according to an exemplary embodiment of the present disclosure.

[0064] Figure 8 An electronic device for implementing the above-described context-keeping method for a mobile terminal, according to an example embodiment of the present disclosure, is illustrated schematically. Detailed Implementation

[0065] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this disclosure more comprehensive and complete, and to fully convey the concept of the example embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced with one or more of the specific details omitted, or other methods, components, apparatus, steps, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0066] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0067] This exemplary embodiment first provides a context-preservation method for a user terminal. This method can run on a network-side server, server cluster, or cloud server, etc. Of course, those skilled in the art can also run the method disclosed herein on other platforms as needed, and this exemplary embodiment does not impose any special limitations on this. References Figure 1 As shown, the context persistence method for this user terminal may include the following steps:

[0068] Step S110. Receive a deregistration request sent by the user terminal, and obtain the context validity time based on the first deregistration timer and the preset second deregistration timer included in the deregistration request;

[0069] Step S120. Generate a deregistration success message based on the context validity period and the context retention success message, and send the deregistration success message to the user terminal;

[0070] Step S130. Maintain the context of the user terminal within the context validity period and receive the re-registration request sent by the user terminal when the system update task is completed;

[0071] Step S140. Cancel the retention of the context according to the context retention shutdown instruction included in the re-registration request, and generate a re-registration success message according to the message of successful cancellation of context retention, so as to send the re-registration success message to the user terminal.

[0072] In the aforementioned context preservation method for user terminals, on the one hand, by receiving a deregistration request sent by the user terminal, the context validity period is obtained based on the first deregistration timer and the preset second deregistration timer included in the deregistration request; then, based on the context validity period and the context preservation success message, a deregistration success message is generated and sent to the user terminal; the user terminal's context is preserved within the context validity period, and a re-registration request sent by the user terminal when the system update task is completed is received; finally, the context preservation is canceled according to the context preservation shutdown instruction included in the re-registration request, and a re-registration success message is generated based on the context preservation cancellation success message. This allows the user terminal to directly use the context saved by the network side within the context validity period without re-establishing the context on the network side when completing the system update task, thereby improving the network access efficiency of the user terminal; on the other hand, during the user terminal's system update task, the user terminal's context can be preserved within the context validity period, thus avoiding the problem of heavy network load caused by the need to recreate the context when the user terminal initiates a re-registration request.

[0073] The following will provide a detailed explanation and description of the context preservation method for a user terminal according to an example embodiment of this disclosure, in conjunction with the accompanying drawings.

[0074] First, the application scenarios of the exemplary embodiments of this disclosure will be explained and described. The technical solutions of the embodiments of this application can be applied to fifth-generation (5G) systems or new radio (NR) communication systems, and can also be applied to other communication systems that may emerge in the future, such as 6G communication systems. Meanwhile, the user terminal described in this application can refer to user equipment (UE), access terminal, terminal in V2X communication, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication equipment, user agent, or user device. The terminal can also be a cellular phone, cordless phone, Session Initiation Protocol (SIP) phone, Wireless Local Loop (WLL) station, Personal Digital Assistant (PDA), handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, in-vehicle device, wearable device, user terminal in future 5G networks, or user terminal in future evolved Public Land Mobile Network (PLMN), etc., and this application embodiment is not limited thereto. The terminal may also include V2X equipment, such as a vehicle or an on-board unit (OBU) in a vehicle.

[0075] The following is combined Figure 2 This section introduces the 5G system. Specifically, Figure 2 This is an example diagram of a 5G system architecture. It should be understood that... Figure 2 The 5G system architecture shown is merely an example and should not be construed as limiting this application. References Figure 2As shown, the system includes Access and Mobility Management Function (AMF) 201, Session Management Function (SMF) 202, Radio Access Network (RAN) 203, Unified Data Management (UDM) 204, Policy Control Function (PCF) 205, User Plane Function (UPF) 206, User Equipment (UE), Unified Data Repository (UDR) 207, Network Exposure Function (NEF) 208, Direct Discovery Name Management Function (DDNMF) 209, and Application Function (AF) 210.

[0076] The main functions of each network element are described as follows: UDM: manages user subscription data and authentication data; UDR: provides storage and retrieval for PCF policies, storage and retrieval of open structured data, and storage of user information for application function requests; PCF: manages network behavior, provides policies and rules to the control plane, and generally makes policy decisions based on subscription information; SMF: mainly performs session management, executes PCF-issued control policies, selects UPF, and manages UE... IP address allocation and other functions; AMF: Access and mobility-related functions such as connection management, mobility management, registration management, access authentication and authorization, reachability management, and security context management; UPF: User plane-related functions such as packet routing and transmission, packet inspection, service usage reporting, QoS processing, lawful interception, uplink packet inspection, and downlink packet storage; (R)AN: (Radio) Access Network, corresponding to different access networks in 5G, such as wired access, wireless base station access, and other methods; NEF: Connects core network elements and external application servers, providing authentication and data forwarding services when external application servers initiate service requests to the core network; DDNMF: Primarily responsible for allocating ProSe communication discovery parameters, as a logical network element, it can be integrated into other network elements during deployment; AF: Can be the application server corresponding to the application; UE: Can support service access; Additionally, the UE supports receiving or sending messages through the PC5 interface. It should be noted that... Figure 2The network elements shown can be hardware devices, chips, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform). It should also be understood that... Figure 2 Some of the network elements shown can be deployed in the same location (such as the same hardware device or software function) or they can be deployed separately. This application does not limit this.

[0077] Secondly, the inventive purpose of the exemplary embodiments of this disclosure will be explained and described. Specifically, in the current 3GPP 5G network, if a user terminal performs a system task update operation, it may be temporarily disconnected from the network. Specifically, since the system update operation is automatically triggered by the user terminal or triggered by the user, but the network side and the application side are unaware of it. At this time, the deregistration process initiated by the user terminal may cause partial deletion of the terminal context on the network side, including the mobility management context and session management context, etc.; in addition, all application-level contexts will also become invalid due to the terminal's disconnection; therefore, when the operation is completed and the user terminal re-initiates the registration process, it is necessary to re-establish the mobility management context and session management context; and these session creation processes all involve signaling for each PDU session and application layer messages, thus triggering a lot of signaling interaction and session re-establishment.

[0078] The context preservation method for user terminals described in this exemplary embodiment introduces terminal context preservation functionality to the user terminal, access and mobility management function entity, session management function entity, and user plane function entity, etc., to collaboratively complete context preservation and traffic caching on both the user terminal side and the network side. This allows the terminal to quickly access the network and services after a brief disconnection due to system upgrades or updates. This reduces the signaling load caused by deregistration, reregistration, and session establishment processes, and shortens the time for the terminal to re-access the network and services. Consequently, it accelerates service recovery while reducing network load, providing a better user experience. The context preservation method for user terminals described in this exemplary embodiment is a supplementary optimization for mobile networks and has good future applications.

[0079] Furthermore, in specific applications, on the one hand, user terminals need to support initiating a deregistration process before operations such as operating system upgrades, with the deregistration request carrying necessary information such as context retention instructions and context retention time; receiving deregistration responses and saving necessary information such as access information and session information; on the other hand, user terminals need to support initiating a reregistration process immediately after operations such as operating system upgrades, with the reregistration request carrying a context retention cancellation instruction, as well as necessary network access information such as user identifier, access and mobility management function entity identifier, and access random number; furthermore, the access and mobility management function entity supports negotiating the context retention time with the terminal; negotiating the session management context retention time with the session management function entity; supporting the retention and cancellation of the terminal's mobility management context; and supporting the retention and cancellation of the context retention after the timer expires. The system allows for the normal deletion of the terminal's mobility management context. Furthermore, the session management function entity supports negotiating the session management context retention time with the access and mobility management function entity; it supports negotiating the retention time of the N4 session context and corresponding downlink user data cache with the user plane function entity; it supports normally deleting the terminal's session management context and notifying the user plane entity to delete the N4 session context and corresponding downlink user data cache after the timer expires; even further, the user plane function entity supports negotiating the retention time of the N4 session context and corresponding downlink user data cache with the session management function entity; it supports caching of downlink user data during context retention; it supports downlink forwarding of downlink user data after context retention is cancelled; and it supports receiving requests from the session management function entity to delete the N4 session context and deleting the corresponding downlink user data cache.

[0080] Furthermore, the communication system involved in the exemplary embodiments of this disclosure will be explained and described. Specifically, refer to... Figure 3 As shown, the communication system may include one or more user terminals 310, a base station 320, a mobile network 330, and an application server 340; wherein, the user terminal 310 is communicatively connected to the base station, the base station is communicatively connected to the mobile network, and the mobile network is communicatively connected to the application server; the user terminal is used to send deregistration requests and / or reregistration requests to the mobile network through the base station and to perform system update tasks; the mobile network is used to implement the context maintenance method of the user terminal described in the example embodiments of this disclosure; and the application server is used to feed back the data that needs to be accessed to the user terminal based on the data fed back by the mobile network, so as to realize normal service access.

[0081] Further reference Figure 4 As shown, mobile network 330 can be as described above. Figure 2The 5G network architecture system shown can also be other network architecture systems, and this example does not impose any special restrictions on it. Furthermore, in the mobile network described in the example embodiments of this disclosure, the network element entities used may include Access and Mobility Management Function (AMF) 401, Session Management Function (SMF) 402, and User Plane Function (UPF) 403; of course, other network element entities may also be used during normal service access by the user terminal, and this example does not impose any special restrictions on them.

[0082] It should be added here that, Figure 3 The user terminal 310 shown and Figure 4 The Access and Mobility Management Function (AMF) 401, Session Management Function (SMF) 402, and User Plane Function (UPF) 403 shown herein, in having Figure 2 In addition to the functions of the UE, Access and Mobility Management Function (AMF) 201, Session Management Function (SMF) 202, and User Plane Function (UPF) 206 shown, the UE also has the following functions:

[0083] The user terminal needs to support initiating a deregistration process before operations such as (1) silent modem reset; (2) security patch update; (3) operating system upgrade; (4) modem software update; wherein the deregistration request carries necessary information such as context retention indication and context retention time; receive the deregistration response and save necessary information such as access information and session information; and the user terminal needs to support initiating a reregistration process immediately after operations such as (1) silent modem reset; (2) security patch update; (3) operating system upgrade; (4) modem software update; wherein the reregistration request carries necessary network access information such as context retention cancellation indication, user identifier, access and mobility management function entity identifier, and access random number;

[0084] Meanwhile, the access and mobility management function entity needs to support negotiating the context retention time with the terminal; negotiating the session management context retention time with the session management function entity; supporting the retention and cancellation of the terminal's mobility management context; and supporting the normal deletion of the terminal's mobility management context after the timer expires.

[0085] Furthermore, the session management function entity needs to support negotiating the session management context retention time with the access and mobility management function entity; support negotiating the retention time of the N4 session context and the corresponding downlink user data cache with the user plane function entity; and support deleting the terminal's session management context normally and notifying the user plane entity to delete the N4 session context and the corresponding downlink user data cache when the timer expires.

[0086] Furthermore, the user plane functional entity needs to support negotiating the retention time of the N4 session context and the corresponding downlink user data cache with the session management functional entity; support caching of downlink user data during the context retention period; support downlink forwarding of downlink user data after context retention is cancelled; and support receiving requests from the session management functional entity to delete the N4 session context and delete the corresponding downlink user data cache.

[0087] The following will combine Figure 3 as well as Figure 4 right Figure 1 The context preservation method of the user terminal shown will be further explained and described.

[0088] In step S110, a deregistration request sent by a user terminal is received, and the context validity time is obtained based on the first deregistration timer and the preset second deregistration timer included in the deregistration request.

[0089] Specifically, before a user terminal needs to perform a system update task (such as Modem Software update), it first needs to send a deregistration request to the mobile network. This deregistration request may include the 5G-GUTI (5G Globally Unique Temporary Identifier), the reason value (Deregistration type) for the system update task to be performed by the user terminal, the access type (AccessType) of the user terminal, the context hold-on indicator, and the first deregistration timer. Specifically, 5G-GUTI = 46003123456781234567890123456123456789012345678901234567890123456789012345678901234567890122; Deregistration type = OS or Modem Upgrade, Access Type = 3GPP, Context Hold-on Timer = 10, and Context Hold-on Indicator = On.

[0090] Furthermore, the mobile network can receive the deregistration request via the Access and Mobility Management Function (AMF) and generate a corresponding context validity period. Specifically, this can be achieved as follows: First, the AMF receives the deregistration request sent by the user terminal and parses the request to obtain a first deregistration timer and a reason value for the system update task that the user terminal needs to perform. Second, the AMF determines a preset second deregistration timer based on the reason value of the system update task, compares the first and second deregistration timers, and obtains the context validity period based on the comparison result. If the duration of the first deregistration timer is greater than the duration of the second deregistration timer, the second deregistration timer is used as the context validity period; if the duration of the first deregistration timer is less than the duration of the second deregistration timer, the first deregistration timer is used as the context validity period.

[0091] For example, when the AMF receives a deregistration request, it can parse the request to obtain the first deregistration timer mentioned above, and compare it with the locally configured second deregistration timer, Local Context Hold-on Timer, to determine the context validity period. For example, if the second deregistration timer is 30 seconds and the first deregistration timer is 10 seconds, then 10 seconds can be taken as the context validity period. It should be noted that since the update duration required for each different system update task is different for the user terminal, to adapt to the duration required for different system update tasks, different second deregistration timers can be set according to the type of system update task. Then, when a deregistration request is received, the second deregistration timer corresponding to the reason value of the system update task included in the deregistration request can be determined, thus determining the corresponding context validity period. Of course, the same second deregistration timer can also be set for all system update tasks; this example does not impose any special restrictions on this.

[0092] In step S120, a deregistration success message is generated based on the context validity period and the context retention success message, and the deregistration success message is sent to the user terminal.

[0093] In this example embodiment, firstly, a successful registration message is generated based on the context validity period and the context retention success message. Specifically, refer to... Figure 5 As shown, the following steps may be included:

[0094] Step S510: The AMF generates a first session management modification request based on the user terminal's terminal identifier, context persistence enable instruction, context validity period, and the reason value of the system update task, and sends the first session management modification request to the session management function entity SMF.

[0095] Step S520: The SMF generates a first N4 session modification request based on the context persistence enable instruction included in the first session management modification request and the N4 session identifier corresponding to the user terminal, and sends the first N4 session modification request to the user plane function entity UPF.

[0096] In step S530, the UPF responds to the first N4 session modification request by sending a first response message indicating context retention success to the SMF. The SMF generates a second response message based on the context retention success message included in the first response message and sends the second response message to the AMF.

[0097] In step S540, the AMF generates a random number corresponding to the user terminal, and generates a registration success message based on the random number, the second response message, and the context validity period.

[0098] The following will explain and describe steps S510-S540. Specifically, firstly, the AMF generates a first session management modification request (Nsmf_PDUSession_UpdateSMContext request) based on the user terminal's terminal identifier (5G-TMSI = 12345678901234567890123456789012), context hold-on indicator = On, context hold-on timer = 10, and the cause value of the system update task (Context hold-on cause = OS or Modem Upgrade), and sends the first session management modification request to the SMF; when the SMF receives the first session management modification request, it generates a first N4 session modification request (N4Session Modification) based on the context hold-on indicator (Packet and Context Hold-on Indicator = On) included in the first session management modification request and the N4 session identifier (N4 Session ID = 10001) corresponding to the user terminal. The system first sends the first N4 session modification request to the UPF. After receiving the first N4 session modification request, the UPF can cache the downlink user data (i.e., downlink traffic data) of all PDU sessions associated with the N4 session, while maintaining the N4 session context, and send a first response message (N4Session Modification Response) to the SMF to indicate that the context holds successfully. The SMF then generates a second response message (Nsmf_PDUSession_UpdateSMContext response) based on the context holds successfully message (Packet and Context Hold-on Indicator = On, indicating that the hold is successful) included in the first response message, and sends the second response message to the AMF. Finally, the AMF generates a random number R corresponding to the user terminal, and generates a deregistration acceptance message based on the random number R = a1b2c3d4, 5G-GUTI, the context hold-on indicator = On included in the second response message, indicating that the hold is successful, and the context hold-on timer = 10.

[0099] Furthermore, upon receiving the successful deregistration message, the message is sent to the user terminal. Once the user terminal receives the message, it saves the access information such as the 5G-GUTI, random number R, and slice identifier S-NSSAI (Single Network Slice Selection Assistance Information), as well as session information such as the session IP address and URSP (UE Route Selection Policy), and then executes the system update task.

[0100] In step S130, the context of the user terminal is maintained within the context validity period, and a re-registration request sent by the user terminal when the system update task is completed is received.

[0101] In this example embodiment, after the mobile network sends a registration success message to the user terminal, it needs to maintain the context associated with the user terminal within the context's validity period in the mobile network. The user terminal's context includes a mobility management context, a session management context, and an N4 session context, etc. Specifically, maintaining the user terminal's context within the context's validity period can be achieved in the following ways: maintaining the N4 session context corresponding to the first N4 session modification request and timing the maintenance time of the N4 session context; and / or maintaining the session management context corresponding to the user terminal and timing the maintenance time of the session management context; and / or maintaining the mobility management context corresponding to the user terminal and timing the maintenance time of the mobility management context.

[0102] Furthermore, within the context's validity period, downlink user data also needs to be cached. Specifically, this can be achieved as follows: the UPF caches the downlink user data of the protocol data unit session associated with the first N4 session modification request.

[0103] Specifically, in practical applications, after the UPF receives the first N4 session modification request from the SMF, the UPF begins caching downlink user data for all PDU sessions associated with that N4 session, while maintaining the N4 session context. After the UPF sends the first response message to the SMF, it begins timing the retention time of the N4 session context; of course, the data caching time is also timed simultaneously. Meanwhile, after the SMF receives the first response message, it begins maintaining the user terminal's session management context (SM Context); and after sending the second response message to the AMF, it begins timing the retention time of the session management context. Finally, after the AMF receives the second response message, it begins maintaining the user terminal's mobility management context (MM Context), and after sending a registration success message to the user terminal, it begins timing the retention time of the mobility management context.

[0104] Furthermore, during the context persistence period, it is also necessary to ensure that the context of the user terminal remains within the context validity period. Specifically, the context persistence method for the user terminal further includes: determining whether the first timeout duration of the session management context is greater than the context validity period; if the first timeout duration is greater than the context validity period, deleting the persisted session management context and stopping the persistence of the session management context; generating an N4 session context deletion request and sending the N4 session context deletion request to the UPF.

[0105] Furthermore, the context retention method for the user terminal also includes: in response to the session context deletion request, the UPF releases the retained N4 session context corresponding to the first N4 session modification request and clears the cached downlink user data.

[0106] For example, in a specific application, if any timeout duration exceeds the context validity period, that is, exceeds the context retention phase (t>T0+Tmin), the access and mobility management function entity initiates the deregistration process for the terminal after the timer expires, which is the same as the standard process; the session management function entity performs the deletion process for all sessions of the terminal after the timer expires, which is the same as the standard process. After receiving the corresponding session deletion message, the session management function entity releases the N4 session context and clears the corresponding cached data packets.

[0107] Furthermore, during the context persistence period, in the Access and Mobility Management Function (AMS) entity, the timer for the Mobility Management Context persistence of the terminal starts counting at time T0; the terminal's registration state is registered (e.g., RM-REGISTERED), and the connection state is idle or connected (e.g., CM-IDLE, CM-CONNECTED); a persistence field is added, with a value of On (default is Off), indicating that the terminal's corresponding Mobility Management Context is in the persistence phase. Except for messages indicating cancellation of persistence, the AMS entity returns a failure for any message requested by other network elements for the terminal during the persistence phase, with the reason being that the Mobility Management Context is being persisted; in the Session Management Function (SMS) entity, the timer for the Mobility Management Context persistence of the terminal starts counting at time T0; a persistence field is added, with a value of On (default is Off), indicating that the terminal's corresponding Session Management Context is in the persistence phase. Except for messages indicating cancellation of persistence, the return a failure for any message requested by other network elements for the terminal during the persistence phase, with the reason being that the Session Management Context is being persisted; in the User Plane Function (MPF) entity, a persistence field is added for each session, with a value of On (default is Off), indicating that the terminal's corresponding session is in the persistence phase. Except for messages instructing cancellation of hold, any messages from other network elements requesting this terminal session during the hold phase will return a failure with the reason value that the session is being held. Additionally, all downlink packets during this hold session will be cached.

[0108] Furthermore, after the user terminal completes the system update task within the context validity period, it also needs to send a re-registration message to the mobile network to initiate a re-registration request to the network side. The re-registration request carries the user terminal's temporary identifier, the access and mobility management function entity identifier, and a context retention disabled instruction. The access and mobility management function entity identifier can be composed of 5G-GUTI and a random number R. This access and mobility management function entity identifier enables the base station to find the corresponding access and mobility management function entity. Furthermore, the 5G-GUTI can be generated in the following way: The 5G-GUTI can include GUAMI (Globally Unique AMF Identifier) ​​and 5G-TMSI (5G-Temporary Mobile Subscription Identifier); among which, GUAMI can include MCC (Mobile Country Code), MNC (Mobile Network Code), and AMF Identifier; AMF Identifier can include AMF Region ID, AMF Set ID, and AMF Pointer; at the same time, the resources of MCC are uniformly allocated and managed by the International Telecommunication Union (ITU) and are used to uniquely identify the country to which the mobile user belongs, with a total of 3 digits; while MNC has only 2 digits of mobile network code, which, together with MCC, uniquely identify a mobile network provider.

[0109] It should be noted that the process of a user terminal sending a re-registration request to the mobile network is as follows: The user terminal first establishes a connection with the base station. After establishing the connection with the base station, it sends a re-registration request to the base station. The base station selects the corresponding AMF based on the AMF information in the 5G-GUTI included in the re-registration request and forwards the re-registration request to the AMF.

[0110] Finally, after the mobile network receives the re-registration request, it also needs to determine the legitimacy of the user terminal. Specifically, the legitimacy determination process can be implemented as follows: First, the re-registration request is parsed to obtain the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information included in the request. Second, the legitimacy of the user terminal is determined based on the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information. Specifically, in the process of determining the legitimacy of the user terminal, it can be determined whether the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information included in the re-registration request are known to be the same as those included in the successful deregistration message. If they match, the user terminal is confirmed to be legitimate; if they do not match, the user terminal is confirmed to be illegitimate.

[0111] In step S140, the context retention is cancelled according to the context retention shutdown indication included in the re-registration request, and a re-registration success message is generated according to the message that the context retention was successfully cancelled, so as to send the re-registration success message to the user terminal.

[0112] In this example embodiment, after determining that the user terminal is legitimate, the retention of all contexts included in the mobile network can be cancelled according to the context retention shutdown indication included in the re-registration request. Specifically, cancelling the retention of the context according to the context retention shutdown indication included in the re-registration request, and generating a re-registration success message based on the message indicating successful cancellation of context retention, can be achieved as follows: First, the AMF generates a second session management modification request based on the 5G globally unique temporary identifier and the context retention shutdown indication, and sends the second session management modification request to the session management function entity (SMF); then, the SMF responds to the second session management modification request, cancels the retention of the session management context corresponding to the user terminal, and stops timing the retention time of the session management context; second, the SMF generates a second N4 session modification request based on the context retention shutdown indication included in the second session management modification request and the N4 session identifier corresponding to the user terminal, and sends the second N4 session modification request to the user plane function entity (SMF). The system first establishes a User Terminal Context (UPF). Then, in response to the second N4 session modification request, the UPF sends the cached downlink user data of the Protocol Data Unit (PDU) session associated with the first N4 session modification request to the user terminal, and cancels the retention of the N4 session context corresponding to the first N4 session modification request. Further, the UPF generates a third response message based on the message indicating successful cancellation of context retention, and sends the third response message to the Service Management Context (SMF). Even further, the SMF generates a fourth response message based on the message indicating successful cancellation of context retention included in the third response message, and sends the fourth response message to the AMF. Finally, the AMF generates a re-registration success message based on the message indicating successful cancellation of context retention included in the fourth response message, cancels the retention of the Mobility Management Context corresponding to the user terminal, and stops timing the retention period of the Mobility Management Context.

[0113] Specifically, once the AMF determines that the user terminal is legitimate, it can look up the user terminal's Mobility Management Context (MM Context), cancel the retention of the MM Context, and stop timing the MM Context. Then, the AMF generates a second Session Management Modification Request (Nsmf_PDUSession_UpdateSMContext Request) based on the 5G globally unique temporary identifier 5G-TMSI=12345678901234567890123456789012 and the Context Hold-on Indicator=Off, and sends the second Session Management Modification Request to the SMF. Next, the SMF cancels the retention of the Session Management Context (SM Context) corresponding to the user terminal and stops timing the retention time of the Session Management Context. Then, the SMF generates a second N4 Session Modification Request (N4 Session Modification) based on the Context Hold-on Indicator=Off included in the second Session Management Modification Request and the N4 Session ID=10001 corresponding to the user terminal. The system first requests and sends a second N4 session modification request to the UPF. Then, the UPF sends the cached downlink user data of the Protocol Data Unit (PDU) session associated with the first N4 session modification request to the user terminal and cancels the N4 session context corresponding to the first N4 session modification request. Further, the UPF generates a third response message, N4 Session Modification Response, based on the message indicating successful cancellation of context holding (Packet and Context Hold-on Indicator = Off), and sends the third response message to the SMF. Even further, the SMF generates a fourth response message, Nsmf_PDUSession_UpdateSMContext response, based on the message indicating successful cancellation of context holding included in the third response message (ContextHold-on Indicator = Off, indicating successful cancellation of context holding), and sends the fourth response message to the AMF. Finally, the AMF generates a re-registration success message (Registration Accept response message) based on the context holding indicator closing instruction included in the fourth response message (Context Hold-on Indicator = Off, indicating that context holding has been cancelled), and sends the re-registration success message to the user terminal. Once the user terminal receives the re-registration success message, normal network access can be performed.

[0114] It should be noted that during the cancellation of the retention context, the Access and Mobility Management Function (AMS) entity determines the legitimacy of the terminal based on the information in the re-registration message, terminates the timer for clearing the Mobility Management Context, and sets the Retention Mobility Management Context field to Off. The AMS entity sends a second Session Management Modification Request to the Session Management Function (SMS) entity, instructing the cancellation of the Retention Session Management Context. The SMS entity terminates the timer for clearing the Session Management Context and sets the Retention Session Management Context field to Off. The SMS entity sends a second N4 Session Modification Request to the User Plane Function (MPF) entity, instructing the cancellation of the Retention N4 Session Context and setting the Retention N4 Session Context field to Off. Simultaneously, the cached downlink user data is sent to the user terminal, and the cached downlink user data is deleted.

[0115] The following will combine Figure 6 The context preservation method for user terminals in the example embodiments of this disclosure will be further explained and described. Specifically, refer to... Figure 6 As shown, the context persistence method for this user terminal may include the following steps:

[0116] Step S601: The user terminal sends a registration request to the AMF;

[0117] Step S602, AMF calculates the context validity time based on the first deregistration timer included in the deregistration request and the second deregistration timer set locally;

[0118] Step S603: AMF sends the first session management modification request to SMF;

[0119] Step S604: SMF sends the first N4 session modification request to UPF;

[0120] In step S605, the UPF caches downlink data of all PDU sessions associated with the N4 session, maintains the N4 session context, starts timing, and sends a first response message to the SMF.

[0121] In step S606, the SMF sends a second response message to the AMF, maintains the session management context of the user terminal, and starts timing.

[0122] Step S607: AMF generates a random number R, generates a deregistration success message based on the random number, the context validity period, and the context retention success message, and sends the deregistration success message to the user terminal.

[0123] In step S608, the AMF maintains the mobility management context of the user terminal and starts timing.

[0124] Step S609: The user terminal executes a system update task and sends a re-registration request to the AMF after the system update task is completed.

[0125] In step S610, the AMF determines whether the user terminal is legitimate based on the 5G-GUTI, R, S-NSSAI and other information included in the re-registration request; if legitimate, the AMF finds the mobility management context of the user terminal and cancels the hold, and stops the timer.

[0126] Step S611, AMF sends a second session management modification request to SMF;

[0127] In step S612, the SMF finds the session management context of the user terminal and cancels the hold, stops the timer, and sends a second N4 session modification request to the UPF;

[0128] In step S613, the UPF sends the cached downlink user data, cancels the retention of the N4 session context, and sends a third response message to the SMF indicating that the retention was successfully canceled.

[0129] In step S614, the SMF sends a fourth response message to the AMF, including an indication that the hold-for-success message has been cancelled;

[0130] Step S615, the AMF sends a re-registration success message to the user terminal, indicating that context persistence has been cancelled;

[0131] In step S616, the user terminal performs normal network access.

[0132] The user terminal context preservation method described in this exemplary embodiment, on the one hand, introduces terminal context preservation functionality to the terminal, access and mobility management functions, session management functions, and user plane functions, collaboratively completing context preservation and traffic caching on the terminal network side. This allows the terminal to quickly reconnect to the network and services after a brief disconnection due to system upgrades or updates. On the other hand, it can reduce the signaling load caused by processes such as deregistration, reregistration, and session establishment to a certain extent, reducing the time for the terminal to reconnect to the network and access services. This reduces network load while accelerating service recovery and providing a better user experience. This patent represents a supplementary optimization for mobile networks and has promising application prospects in the future.

[0133] This disclosure also provides an example embodiment of a context-keeping device for a user terminal. Specifically, refer to... Figure 7 As shown, the context holding device of the user terminal may include a context validity period calculation module 710, a deregistration success message generation module 720, a context holding module 730, and a reregistration success message generation module 740. Wherein:

[0134] The context validity time calculation module 710 can be used to receive a deregistration request sent by a user terminal and obtain the context validity time based on the first deregistration timer and the preset second deregistration timer included in the deregistration request.

[0135] The registration success message generation module 720 can be used to generate a registration success message based on the context validity period and the context retention success message, and send the registration success message to the user terminal.

[0136] The context persistence module 730 can be used to persist the context of the user terminal during the context validity period and receive the re-registration request sent by the user terminal when the system update task is completed.

[0137] The re-registration success message generation module 740 can be used to cancel the retention of the context according to the context retention shutdown indication included in the re-registration request, and generate a re-registration success message according to the message of successful cancellation of context retention, so as to send the re-registration success message to the user terminal.

[0138] In one exemplary embodiment of this disclosure, a deregistration request sent by a user terminal is received, and the context validity time is obtained based on a first deregistration timer and a preset second deregistration timer included in the deregistration request, including:

[0139] The Access and Mobility Management Function (AMF) receives the deregistration request sent by the user terminal and parses the deregistration request to obtain the first deregistration timer included in the deregistration request, as well as the reason value of the system update task that the user terminal needs to perform.

[0140] The AMF determines the preset second deregistration timer based on the cause value of the system update task, compares the first deregistration timer and the second deregistration timer, and obtains the context validity time based on the comparison result;

[0141] Wherein, if the duration of the first deregistration timer is greater than the duration of the second deregistration timer, then the second deregistration timer is used as the context valid time; if the duration of the first deregistration timer is less than the duration of the second deregistration timer, then the first deregistration timer is used as the context valid time.

[0142] In one exemplary embodiment of this disclosure, generating a deregistration success message based on the context validity period and the context retention success message includes:

[0143] The AMF generates a first session management modification request based on the user terminal's terminal identifier, context persistence enable instruction, context validity period, and the reason value of the system update task, and sends the first session management modification request to the session management function entity SMF;

[0144] The SMF generates a first N4 session modification request based on the context persistence enable instruction included in the first session management modification request and the N4 session identifier corresponding to the user terminal, and sends the first N4 session modification request to the User Plane Function Entity (UPF).

[0145] In response to the first N4 session modification request, the UPF sends a first response message indicating context retention success to the SMF. The SMF generates a second response message based on the context retention success message included in the first response message and sends the second response message to the AMF.

[0146] The AMF generates a random number corresponding to the user terminal, and generates a registration success message based on the random number, the second response message, and the context validity period.

[0147] In one exemplary embodiment of this disclosure, the context of the user terminal includes at least one of a mobility management context, a session management context, and an N4 session context;

[0148] The maintenance of the user terminal's context during the context's validity period includes:

[0149] Maintain the N4 session context corresponding to the first N4 session modification request, and time the retention period of the N4 session context; and / or

[0150] Maintain the session management context corresponding to the user terminal, and time the retention period of the session management context; and / or

[0151] Maintain the mobility management context corresponding to the user terminal and time the duration of the mobility management context maintenance.

[0152] In one exemplary embodiment of this disclosure, the context holding device of the user terminal further includes:

[0153] The data caching module can be used to cache the downlink user data of the protocol data unit session associated with the first N4 session modification request.

[0154] In one exemplary embodiment of this disclosure, the context holding device of the user terminal further includes:

[0155] The first duration determination module can be used to determine whether the first timing duration of the session management context is greater than the context validity time.

[0156] The session management context deletion module can be used to delete the maintained session management context and stop maintaining the session management context if the first timing duration is longer than the context validity time.

[0157] The N4 session context deletion request module can be used to generate an N4 session context deletion request and send the N4 session context deletion request to the UPF.

[0158] In one exemplary embodiment of this disclosure, the context holding device of the user terminal further includes:

[0159] The N4 session context release module can be used by the UPF in response to the session context deletion request to release the N4 session context that has been maintained and corresponds to the first N4 session modification request, and to clear the cached downlink user data.

[0160] In one exemplary embodiment of this disclosure, the context holding device of the user terminal further includes:

[0161] The re-registration request parsing module can be used to parse the re-registration request to obtain the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information included in the re-registration request;

[0162] The user terminal legitimacy determination module can be used to determine whether the user terminal is legitimate based on the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information.

[0163] In one exemplary embodiment of this disclosure, the retention of the context is cancelled according to the context retention closure indication included in the re-registration request, and a re-registration success message is generated according to the message indicating successful cancellation of context retention, including:

[0164] AMF generates a second session management modification request based on the 5G globally unique temporary identifier and the context preservation off instruction, and sends the second session management modification request to the session management function entity SMF;

[0165] In response to the second session management modification request, the SMF cancels the retention of the session management context corresponding to the user terminal and stops counting down the retention time of the session management context;

[0166] The SMF generates a second N4 session modification request based on the context retention off indication included in the second session management modification request and the N4 session identifier corresponding to the user terminal, and sends the second N4 session modification request to the User Plane Function Entity (UPF).

[0167] In response to the second N4 session modification request, the UPF sends the cached downlink user data of the Protocol Data Unit session associated with the first N4 session modification request to the user terminal, and cancels the maintenance of the N4 session context corresponding to the first N4 session modification request.

[0168] The UPF generates a third response message based on the message indicating that the context preservation was successfully cancelled, and sends the third response message to the SMF.

[0169] The SMF generates a fourth response message based on the message indicating successful cancellation of context preservation included in the third response message, and sends the fourth response message to the AMF;

[0170] The AMF generates a re-registration success message based on the context retention indication cancellation success message included in the fourth response message, and cancels the retention of the mobility management context corresponding to the user terminal, and stops timing the retention time of the mobility management context.

[0171] In one exemplary embodiment of this disclosure, the system update task includes at least one of modem silent reset update, security patch update, operating system update, and modem software update.

[0172] The specific details of each module in the context persistence device of the aforementioned user terminal have been described in detail in the context persistence method of the corresponding user terminal, so they will not be repeated here.

[0173] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0174] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0175] In an exemplary embodiment of this disclosure, an electronic device capable of implementing the above-described method is also provided.

[0176] Those skilled in the art will understand that various aspects of this disclosure can be implemented as a system, method, or program product. Therefore, various aspects of this disclosure can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software aspects, collectively referred to herein as a "circuit," "module," or "system."

[0177] The following reference Figure 8 To describe an electronic device 800 according to such an embodiment of the present disclosure. Figure 8 The electronic device 800 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments disclosed herein.

[0178] like Figure 8 As shown, the electronic device 800 is manifested in the form of a general-purpose computing device. The components of the electronic device 800 may include, but are not limited to: at least one processing unit 810, at least one storage unit 820, a bus 830 connecting different system components (including storage unit 820 and processing unit 810), and a display unit 840.

[0179] The storage unit stores program code that can be executed by the processing unit 810, causing the processing unit 810 to perform the steps described in the "Exemplary Methods" section of this specification according to various exemplary embodiments of this disclosure. For example, the processing unit 810 can perform actions such as... Figure 1 Step S110: Receive a deregistration request sent by the user terminal, and obtain the context validity period based on the first deregistration timer and the preset second deregistration timer included in the deregistration request; Step S120: Generate a deregistration success message based on the context validity period and the context retention success message, and send the deregistration success message to the user terminal; Step S130: Retain the context of the user terminal within the context validity period, and receive a reregistration request sent by the user terminal when the system update task is completed; Step S140: Cancel the retention of the context according to the context retention shutdown indication included in the reregistration request, and generate a reregistration success message based on the context retention cancellation success message, and send the reregistration success message to the user terminal.

[0180] Storage unit 820 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 8201 and / or cache memory 8202, and may further include a read-only memory (ROM) 8203.

[0181] The storage unit 820 may also include a program / utility 8204 having a set (at least one) of program modules 8205, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0182] Bus 830 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0183] Electronic device 800 can also communicate with one or more external devices 900 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 800, and / or with any device that enables electronic device 800 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 850. Furthermore, electronic device 800 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 860. As shown, network adapter 860 communicates with other modules of electronic device 800 via bus 830. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 800, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0184] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, terminal device, or network device, etc.) to execute the methods according to the embodiments of this disclosure.

[0185] In exemplary embodiments of this disclosure, a computer-readable storage medium is also provided, on which a program product capable of implementing the methods described above is stored. In some possible implementations, various aspects of this disclosure may also be implemented as a program product including program code that, when the program product is run on a terminal device, causes the terminal device to perform the steps of the various exemplary embodiments of this disclosure described in the "Exemplary Methods" section above.

[0186] The program product for implementing the above-described method according to embodiments of the present disclosure may employ a portable compact disc read-only memory (CD-ROM) and include program code, and may run on a terminal device, such as a personal computer. However, the program product of the present disclosure is not limited thereto. In this document, the readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0187] The program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0188] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of sending, propagating, or transmitting programs for use by or in conjunction with an instruction execution system, apparatus, or device.

[0189] The program code contained on the readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0190] Program code for performing the operations of this disclosure can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0191] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of this disclosure and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0192] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention described herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not invented by this disclosure. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

Claims

1. A method for maintaining the context of a user terminal, characterized in that, include: Receive a deregistration request sent by a user terminal, and obtain the context validity time based on the first deregistration timer and the preset second deregistration timer included in the deregistration request; Based on the context validity period and the context retention success message, a deregistration success message is generated and sent to the user terminal; The context of the user terminal is maintained within the context validity period, and a re-registration request is received from the user terminal when the system update task is completed. The context retention is cancelled according to the context retention shutdown instruction included in the re-registration request, and a re-registration success message is generated according to the message that the context retention was cancelled successfully, so as to send the re-registration success message to the user terminal. The context validity period is obtained as follows: The Access and Mobility Management Function (AMF) receives a deregistration request from the user terminal and parses the request to obtain a first deregistration timer and a reason value for the system update task to be performed by the user terminal. The AMF determines a preset second deregistration timer based on the reason value of the system update task, compares the first and second deregistration timers, and obtains the context validity period based on the comparison result. If the duration of the first deregistration timer is greater than the duration of the second deregistration timer, the second deregistration timer is used as the context validity period; if the duration of the first deregistration timer is less than the duration of the second deregistration timer, the first deregistration timer is used as the context validity period.

2. The context preservation method for a user terminal according to claim 1, characterized in that, Based on the context validity period and the context retention success message, generate a deregistration success message, including: The AMF generates a first session management modification request based on the user terminal's terminal identifier, context persistence enable instruction, context validity period, and the reason value of the system update task, and sends the first session management modification request to the session management function entity SMF; The SMF generates a first N4 session modification request based on the context persistence enable instruction included in the first session management modification request and the N4 session identifier corresponding to the user terminal, and sends the first N4 session modification request to the User Plane Function Entity (UPF). In response to the first N4 session modification request, the UPF sends a first response message indicating context retention success to the SMF. The SMF generates a second response message based on the context retention success message included in the first response message and sends the second response message to the AMF. The AMF generates a random number corresponding to the user terminal, and generates a registration success message based on the random number, the second response message, and the context validity period.

3. The context preservation method for a user terminal according to claim 2, characterized in that, The context of the user terminal includes at least one of mobility management context, session management context, and N4 session context; The maintenance of the user terminal's context during the context's validity period includes: Maintain the N4 session context corresponding to the first N4 session modification request, and time the retention period of the N4 session context; and / or Maintain the session management context corresponding to the user terminal, and time the retention period of the session management context; and / or Maintain the mobility management context corresponding to the user terminal and time the duration of the mobility management context maintenance.

4. The context preservation method for a user terminal according to claim 2, characterized in that, The context persistence method for the user terminal further includes: Downlink user data for the protocol data unit session associated with the first N4 session modification request is cached.

5. The context preservation method for a user terminal according to claim 3, characterized in that, The context persistence method for the user terminal further includes: Determine whether the first timing duration of the session management context is greater than the context validity period; If the first timing duration is longer than the context validity period, the maintained session management context is deleted and the maintenance of the session management context is stopped. Generate an N4 session context deletion request and send the N4 session context deletion request to the UPF.

6. The context preservation method for a user terminal according to claim 5, characterized in that, The context persistence method for the user terminal further includes: In response to the session context deletion request, the UPF releases the N4 session context that has been maintained and corresponds to the first N4 session modification request, and clears the cached downlink user data.

7. The context preservation method for a user terminal according to claim 2, characterized in that, After receiving the re-registration request sent by the user terminal upon completion of the system update task, the context maintenance method of the user terminal further includes: The re-registration request is parsed to obtain the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information included in the re-registration request; The legitimacy of the user terminal is determined based on the 5G globally unique temporary identifier, random number, and single network slice selection auxiliary information.

8. The context preservation method for a user terminal according to claim 7, characterized in that, The re-registration request cancels the retention of the context according to the context retention shutdown indication included in the re-registration request, and generates a re-registration success message based on the message indicating successful cancellation of context retention, including: AMF generates a second session management modification request based on the 5G globally unique temporary identifier and the context preservation off instruction, and sends the second session management modification request to the session management function entity SMF; In response to the second session management modification request, the SMF cancels the retention of the session management context corresponding to the user terminal and stops counting down the retention time of the session management context; The SMF generates a second N4 session modification request based on the context retention off indication included in the second session management modification request and the N4 session identifier corresponding to the user terminal, and sends the second N4 session modification request to the User Plane Function Entity (UPF). In response to the second N4 session modification request, the UPF sends the cached downlink user data of the Protocol Data Unit session associated with the first N4 session modification request to the user terminal, and cancels the maintenance of the N4 session context corresponding to the first N4 session modification request. The UPF generates a third response message based on the message indicating that the context preservation was successfully cancelled, and sends the third response message to the SMF. The SMF generates a fourth response message based on the message indicating successful cancellation of context preservation included in the third response message, and sends the fourth response message to the AMF; The AMF generates a re-registration success message based on the context retention indication cancellation success message included in the fourth response message, and cancels the retention of the mobility management context corresponding to the user terminal, and stops timing the retention time of the mobility management context.

9. A context-keeping device for a user terminal, characterized in that, include: The context validity time calculation module is used to receive a deregistration request sent by the user terminal and obtain the context validity time based on the first deregistration timer and the preset second deregistration timer included in the deregistration request. The registration success message generation module is used to generate a registration success message based on the context validity period and the context retention success message, and send the registration success message to the user terminal. The context persistence module is used to persist the context of the user terminal during the context validity period and to receive the re-registration request sent by the user terminal when the system update task is completed. The re-registration success message generation module is used to cancel the retention of the context according to the context retention shutdown indication included in the re-registration request, and generate a re-registration success message according to the message of successful cancellation of context retention, so as to send the re-registration success message to the user terminal. The context validity period is obtained as follows: The Access and Mobility Management Function (AMF) receives a deregistration request from the user terminal and parses the request to obtain a first deregistration timer and a reason value for the system update task to be performed by the user terminal. The AMF determines a preset second deregistration timer based on the reason value of the system update task, compares the first and second deregistration timers, and obtains the context validity period based on the comparison result. If the duration of the first deregistration timer is greater than the duration of the second deregistration timer, the second deregistration timer is used as the context validity period; if the duration of the first deregistration timer is less than the duration of the second deregistration timer, the first deregistration timer is used as the context validity period.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the context preservation method for the user terminal as described in any one of claims 1-8.

11. An electronic device, characterized in that, include: processor; as well as Memory for storing the executable instructions of the processor; The processor is configured to execute the context preservation method of any one of claims 1-8 by executing the executable instructions.

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