Session management method, apparatus and system

Abstract

The present application is applied to the technical field of communications. Provided are a session management method, apparatus and system. By means of the session management method provided in the present application, once a new user logs in to a terminal device, one or more sessions previously created for an old user can be released in a timely manner, so as to preventing the establishment of a session for the new user from being impacted. The communication method comprises: once a first user logs in to a terminal device, a first network element or the terminal device acquiring the identity of the first user; on the basis of the identity of the first user, determining to release one or more first sessions, wherein the one or more first sessions belong to at least one second session created by a second user by means of the terminal device, and the second user logs in to the terminal device prior to the first user; and the first network element or the terminal device then triggering the release of the one or more first sessions.

Description

Session management method, device and system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on April 3, 2024, with application number 202410417495.1 and application name “Session Management Method, Device and System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a session management method, device, and system. Background Art

[0003] In current network architectures, the network provides network services to terminal devices based on their Subscription Permanent Identifier (SUPI). A terminal device's SUPI is a unique identifier assigned by the network to its Subscriber Identity Module (SIM) card. When a terminal device requests a service from the network, the network identifies the SUPI and provides the corresponding network service based on the subscription data associated with the SUPI. However, in this scenario, the network cannot determine the specific user of the terminal device.

[0004] A new approach is being proposed: using a user identity (User ID) to represent the user logged into a terminal device at a given moment. Only one user with the same User ID can be logged into a terminal device at a time. The introduction of user identity offers a more flexible service approach. When different users access the network using a terminal device, the network can provide corresponding network services based on their respective subscription information.

[0005] In 5th generation (5G) mobile communication networks, services on terminal devices are carried out through protocol data unit (PDU) sessions. The network can establish a corresponding PDU session for the terminal device based on the terminal device's SUPI. If user identification is introduced, the network can establish a PDU session corresponding to the user identification based on the user identification. However, when a new user logs in, there may be cases where a PDU session cannot be successfully established for the new user. Summary of the Invention

[0006] The embodiments of the present application provide a session management method, apparatus, and system, which can promptly release one or more sessions originally established for an old user after a new user logs in to a terminal device to avoid affecting the session established for the new user.

[0007] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0008] In a first aspect, a session management method is provided, which can be executed by a first network element or terminal device, or can also be executed by a module (such as a processor, chip, or chip system, etc.) applied to the first network element or terminal device. The following is an example of the first network element or terminal device executing the session management method. The method includes: after a first user logs in to the terminal device, the first network element or terminal device obtains an identifier of the first user, and determines to release one or more first sessions based on the first user identifier, wherein the one or more first sessions belong to at least one second session established by a second user through the terminal device, and the second user logs in to the terminal device before the first user. Furthermore, the first network element or terminal device triggers the release of the one or more first sessions.

[0009] Based on the session management method provided in the embodiment of the present application, after a new user (i.e., the first user mentioned above) logs in to the terminal device, the release of the session established for the old user (i.e., the second user mentioned above) can be triggered in a timely manner to ensure that the session established for the new user will not be affected.

[0010] In combination with the above-mentioned first aspect, in a possible design, determining to release one or more first sessions based on the identifier of the first user includes: when it is determined based on the identifier of the first user that the user logged into the terminal device has changed, the first network element or terminal device determines to release one or more first sessions.

[0011] Based on this solution, the network side or the terminal device side can identify that a user who logs into the terminal device has changed, and can further determine which sessions to release based on the change.

[0012] In combination with the above-mentioned first aspect, in a possible design, determining to release one or more first sessions based on the identifier of the first user includes: when receiving a release request from the terminal device, the first network element determines to release one or more first sessions, wherein the release request includes the identifier of the first user.

[0013] Based on this solution, the network side can determine which sessions to release based on the release request of the terminal device.

[0014] In conjunction with the first aspect above, in one possible design, determining to release one or more first sessions based on the identifier of the first user includes: a first network element sending a first message to another network element, where the first message includes the identifier of the first user, and the first message is used to request user information or contract data corresponding to the identifier of the first user. The first network element receives user information or contract data corresponding to the identifier of the first user from the other network element, and determines one or more first sessions based on the user information or contract data corresponding to the identifier of the first user.

[0015] Based on this solution, the first network element can determine which sessions to release based on the user information or subscription data corresponding to the user identifier of the new user.

[0016] In combination with the first aspect above, in a possible design, one or more first sessions are determined based on user information or subscription data corresponding to the identifier of the first user, including: the first network element determines the parameters subscribed by the identifier of the first user based on the user information or subscription data corresponding to the identifier of the first user, the parameters being used to determine the session, for example, the parameters may include at least one of the following: data network name (DNN) or single network slice selection assistance information (S-NSSAI) information. The first network element determines, based on the parameters subscribed by the identifier of the first user and the parameters corresponding to each second session in at least one second session, a second session whose corresponding parameters are different from the parameters subscribed by the identifier of the first user as the first session.

[0017] Based on this solution, the first network element compares the parameters subscribed by the user identifier of the new user with the relevant parameters of the second session. The second session whose corresponding parameters are different from the parameters subscribed by the new user's identifier can be considered as a session that cannot be reused by the first user. Based on this, the first network element can release the session that cannot be reused by the first user and retain the session that can be reused by the first user. When subsequently establishing a session for the first user, these retained sessions can be reused to improve efficiency.

[0018] In conjunction with the first aspect above, in one possible design, the second user can log in to the terminal device using a default mode, or can log in to the terminal device using the second user's identifier. After the second user logs in to the terminal device, the method further includes: the first network element receiving first indication information, the first indication information being used to instruct the second user to log in to the terminal device using the default mode or the second user to log in to the terminal device using the second user's identifier. In addition, the first user can log in to the terminal device using the first user's identifier.

[0019] Based on this solution, the first network element can determine, through the first indication information, the mode through which the second user logs into the terminal device.

[0020] In combination with the above-mentioned first aspect, in a possible design, after receiving the first indication information, the method also includes: the first network element records the first indication information in the description information of the terminal device, such as the context of the terminal device.

[0021] In combination with the first aspect above, in one possible design, the method further includes:

[0022] The first network element sends a second message to other network elements, where the second message includes first indication information and is used to request establishment of a session management context for a session corresponding to the second user.

[0023] In combination with the above-mentioned first aspect, in a possible design, the method further includes: when the first indication information indicates that the second user logs in to the terminal device through the default mode, the other network elements obtain the user information or contract data corresponding to the terminal device, and determine whether to establish a context for the session corresponding to the second user based on the user information or contract data corresponding to the terminal device. When the first indication information indicates that the second user logs in to the terminal device using the second user's identifier, the other network elements obtain the user information or contract data corresponding to the second user's identifier, and determine whether to establish a context for the session corresponding to the second user based on the user information or contract data corresponding to the second user's identifier.

[0024] Based on this solution, when the first network element establishes a session for the second user, it can indicate to other network elements the mode in which the second user logged into the terminal device, so that other network elements can query the corresponding user information or contract data and decide whether to establish a session context for the second user.

[0025] In combination with the above-mentioned first aspect, in a possible design, the first network element obtains the identifier of the first user, including: the first network element receives a third message from the terminal device, and the third message includes the identifier of the first user; wherein the third message is used to request that the first user be registered to the network; or, the third message is used to request the network to authenticate the first user; or, the third message is used to request to establish a session for the first user.

[0026] Based on this solution, the first network element can obtain the identifier of the first user during the process of user registration / authentication / session establishment.

[0027] In combination with the foregoing first aspect, in one possible design, the first network element triggers the release of one or more first sessions, including:

[0028] The first network element sends a fourth message, where the fourth message includes identification information for identifying one or more second sessions, for example, may include a PUD session ID of the second session, and the fourth message is used to request the release of the one or more second sessions.

[0029] In combination with the foregoing first aspect, in one possible design, the first network element obtains the identifier of the first user, including:

[0030] The first network element receives a fifth message from another network element. The fifth message includes an identifier of the first user and is used to request establishment of a context for a session corresponding to the first user. In this design, the first network element may be a session management function (SMF) network element, and the other network element that sends the fifth message may be an access and mobility management function (AMF) network element.

[0031] Based on this solution, the first network element can obtain the identifier of the first user through messages interacting with other network elements during the process of establishing a session for the first user.

[0032] In combination with the foregoing first aspect, in one possible design, before the first network element receives the fifth message from the other network element, the method further includes:

[0033] The other network element receives a seventh message from the terminal device, where the seventh message includes second indication information, where the second indication information is used to indicate that the terminal device can be logged in by different users at different times. The other network element determines, based on the second indication information, to select the same first network element or a first network element in the same set when establishing sessions corresponding to different users for the terminal device.

[0034] In the case that the other network elements select the same first network element, before the first network element receives the fifth message from the other network elements, the method further includes:

[0035] The first network element receives an eighth message from another network element, where the eighth message includes first indication information and is used to request establishment of a context for a session corresponding to the second user.

[0036] Based on this solution, other network elements can select the same first network element or the first network element in the same set for the terminal device when establishing a session for the terminal device according to the instructions of the terminal device, so that the same first network element (or the first network element in the same set) establishes sessions for the second user and the first user successively, so that when the first network element establishes a session for the first user, it can identify the change of the user who logged into the terminal device and trigger the release of one or more first sessions.

[0037] In a second aspect, a communication device is provided for implementing the method implemented by the first network element or terminal device in the above-mentioned first aspect.

[0038] The communication device includes modules, units, or means corresponding to the above-mentioned method, which can be implemented by hardware, software, or hardware executing corresponding software implementation. The hardware or software includes one or more modules or units corresponding to the above-mentioned functions.

[0039] In conjunction with the second aspect above, in one possible design, the communication device includes an acquisition module and a processing module; the acquisition module is configured to acquire an identifier of the first user after the first user logs into a terminal device. The processing module is configured to determine, based on the first user identifier, whether to release one or more first sessions, where the one or more first sessions belong to at least one second session established by a second user through the terminal device, who logged into the terminal device before the first user. The processing module is further configured to trigger the release of the one or more first sessions.

[0040] In combination with the above-mentioned second aspect, in a possible design, the processing module determines to release one or more first sessions based on the identifier of the first user, including: when it is determined based on the identifier of the first user that the user logged into the terminal device has changed, determining to release one or more first sessions.

[0041] In conjunction with the second aspect, in one possible design, the communication device further includes a transceiver module configured to receive a release request from a terminal device, wherein the release request includes an identifier of the first user. The processing module determining, based on the identifier of the first user, to release one or more first sessions includes: determining to release the one or more first sessions based on the release request.

[0042] In combination with the above-mentioned second aspect, in one possible design, the communication device further includes a transceiver module, the transceiver module being configured to send a first message to other network elements, the first message including an identifier of the first user, and the first message being configured to request user information or contract data corresponding to the identifier of the first user. The transceiver module is further configured to receive user information or contract data corresponding to the identifier of the first user from other network elements. The processing module determining, based on the identifier of the first user, to release one or more first sessions includes: determining one or more first sessions based on the user information or contract data corresponding to the identifier of the first user.

[0043] In combination with the above-mentioned second aspect, in a possible design, the processing module determines one or more first sessions based on the user information or contract data corresponding to the identifier of the first user, including: determining the parameters subscribed to by the identifier of the first user based on the user information or contract data corresponding to the identifier of the first user, the parameters are used to determine the session, for example, the parameters may include at least one of the following: DNN or S-NSSAI; based on the parameters subscribed to by the identifier of the first user, and the parameters corresponding to each second session in at least one second session, determining the second session whose corresponding parameters are different from the parameters subscribed to by the identifier of the first user as the first session.

[0044] In combination with the above-mentioned second aspect, in a possible design, the communication device also includes a transceiver module, which is used to receive first indication information, and the first indication information is used to instruct the second user to log in to the terminal device through the default mode or the second user to log in to the terminal device through the second user's identification.

[0045] In combination with the above-mentioned second aspect, in a possible design, the communication device also includes a storage module, which is used to record the first indication information in the description information of the terminal device, such as the context of the terminal device.

[0046] In combination with the above-mentioned second aspect, in a possible design, the communication device also includes a transceiver module, which is used to send a second message to other network elements, and the second message includes first indication information, and the second message is used to request to establish a session management context for the session corresponding to the second user.

[0047] In combination with the above-mentioned second aspect, in a possible design, the communication device also includes a transceiver module and an acquisition module, which are specifically used to: receive a third message from the terminal device through the transceiver module, and the third message includes the identifier of the first user; wherein the third message is used to request that the first user be registered to the network; or, the third message is used to request the network to authenticate the first user; or, the third message is used to request that a session be established for the first user.

[0048] In combination with the above-mentioned second aspect, in a possible design, the communication device also includes a transceiver module, and the processing module triggers the release of one or more first sessions, including: sending a fourth message through the transceiver module, the fourth message including identification information for identifying one or more second sessions, for example, may include the PUD session ID of the second session, and the fourth message is used to request the release of one or more second sessions.

[0049] In combination with the above-mentioned second aspect, in a possible design, the communication device also includes a transceiver module and an acquisition module, which are specifically used to: receive a fifth message from other network elements through the transceiver module, the fifth message including the identifier of the first user, and the fifth message is used to request to establish the context of the session corresponding to the first user.

[0050] In combination with the above-mentioned second aspect, in a possible design, the communication device also includes a transceiver module, which is used to receive an eighth message from other network elements, where the eighth message includes first indication information, and the eighth message is used to request to establish the context of the session corresponding to the second user.

[0051] In a third aspect, a communication device is provided for implementing the method implemented by other network elements in the first aspect.

[0052] The communication device includes modules, units, or means corresponding to the above-mentioned method, which can be implemented by hardware, software, or hardware executing corresponding software implementation. The hardware or software includes one or more modules or units corresponding to the above-mentioned functions.

[0053] In combination with the third aspect above, in one possible design, the communication device includes an acquisition module, a processing module and a transceiver module; the transceiver module is used to receive a second message from the first network element, the second message includes first indication information, and the second message is used to request the establishment of a session management context for the session corresponding to the second user. In the case where the first indication information indicates that the second user logs in to the terminal device through the default mode, the acquisition module is used to obtain user information or contract data corresponding to the terminal device; the processing module is used to determine whether to establish a context for the session corresponding to the second user based on the user information or contract data corresponding to the terminal device. In the case where the first indication information indicates that the second user logs in to the terminal device through the second user's identifier, the acquisition module is used to obtain user information or contract data corresponding to the second user's identifier, and the processing module is used to determine whether to establish a context for the session corresponding to the second user based on the user information or contract data corresponding to the second user's identifier.

[0054] In a fourth aspect, a communication device is provided for implementing the method implemented by other network elements in the first aspect.

[0055] The communication device includes modules, units, or means corresponding to the above-mentioned method, which can be implemented by hardware, software, or hardware executing corresponding software implementation. The hardware or software includes one or more modules or units corresponding to the above-mentioned functions.

[0056] In conjunction with the fourth aspect, in one possible design, the communication device includes a transceiver module and a processing module; the transceiver module is configured to receive a seventh message from a terminal device, the seventh message including second indication information, where the second indication information is used to indicate that the terminal device can be logged in by different users at different times. The processing module is configured to determine, based on the second indication information, whether to select the same first network element or first network elements in the same set when establishing sessions corresponding to different users for the terminal device.

[0057] In a fifth aspect, a communication device is provided, comprising: a processor configured to execute instructions stored in a memory, wherein when the processor executes the instructions, the communication device performs the method described in any of the above aspects. The communication device may be the first network element, a module (e.g., a chip) applied to the first network element, a terminal device, a module (e.g., a chip) applied to the terminal device, another network element, or a module (e.g., a chip) applied to another network element, in the first aspect or any possible design of the first aspect.

[0058] In one possible design, the communication device further includes a memory for storing computer instructions. Optionally, the processor and the memory are integrated together, or the processor and the memory are separately provided.

[0059] In one possible design, the memory is coupled to the processor and is external to the communication device.

[0060] In a sixth aspect, a communication device is provided, comprising: a processor and an interface circuit, the interface circuit being configured to communicate with a module outside the communication device; the processor being configured to execute the method described in any of the above aspects via a logic circuit or by running a computer program or instruction. The communication device may be the first network element, a module (e.g., a chip) applied to the first network element, a terminal device, a module (e.g., a chip) applied to the terminal device, another network element, or a module (e.g., a chip) applied to another network element, in the above first aspect or any possible design of the first aspect.

[0061] Alternatively, the interface circuit can be a code / data read / write interface circuit, which is used to receive computer execution instructions (the computer execution instructions are stored in the memory, may be read directly from the memory, or may pass through other devices) and transmit them to the processor so that the processor runs the computer execution instructions to execute the method described in any of the above aspects.

[0062] In one possible design, the communication device further includes a memory for storing computer programs or instructions. Optionally, the processor and the memory are integrated together, or the processor and the memory are separately provided.

[0063] In one possible design, the memory is coupled to the processor and is external to the communication device.

[0064] In some possible designs, the communication device may be a chip or a chip system.

[0065] In the seventh aspect, the present application provides a computer-readable storage medium, which stores instructions. When the instructions are run on a computer, the computer can execute the method performed by the first network element, terminal device or other network element in the above-mentioned first aspect, or any possible design of the first aspect.

[0066] In an eighth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method executed by the first network element, terminal device or other network element in the above-mentioned first aspect, or any possible design of the first aspect.

[0067] In a ninth aspect, a communication device (for example, a chip or a chip system) is provided, wherein the communication device includes a processor for implementing the functions involved in any of the above aspects. In one possible design, the communication device also includes a memory for storing necessary program instructions and data. When the communication device is a chip system, it can be composed of a chip or include a chip and other discrete devices.

[0068] In a tenth aspect, a communication system is provided, comprising a first network element and other network elements. The first network element is configured to implement the method implemented by the first network element in the first aspect. The other network elements are configured to implement the method implemented by the other network elements in the first aspect.

[0069] Among them, the technical effects brought about by any design method in the second to tenth aspects can refer to the technical effects brought about by the different design methods in the above-mentioned first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG1 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0071] FIG2 is a schematic diagram of a network architecture provided in an embodiment of the present application;

[0072] FIG3 is a flow chart of a session management method according to an embodiment of the present application;

[0073] FIG4 is a schematic diagram of a process provided in an embodiment of the present application;

[0074] FIG5 is an interactive diagram of another process provided in an embodiment of the present application;

[0075] FIG6 is an interactive diagram of another process provided in an embodiment of the present application;

[0076] FIG7 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0077] FIG8 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0078] In order to facilitate understanding of the technical solutions of the embodiments of the present application, a brief introduction to the relevant technologies of the present application is first given as follows.

[0079] 1. User ID:

[0080] In the application scenario where the concept of user identification is introduced, the user can sign a contract with the operator and obtain his or her corresponding user identification. The network side saves the user's corresponding contract data (or contract information) and records the user identification. When the user logs in to the terminal device based on the user identification, the network can obtain the user identification and query the user's corresponding contract data through the user identification, thereby providing the user with corresponding network services (or providing the terminal device with corresponding network services) based on the user's contract data. It can be seen that compared to the method of providing network services to terminal devices based on the terminal device's unique SUPI, the introduction of user identification proposes a smaller-granularity and more flexible service method. When different users use the same terminal device to access the network, the network can identify different users and provide different network services based on the contract information of different users.

[0081] For example, shared cars are configured with a SUPI (Super User Information Interface) when they leave the factory, making them capable of functioning as terminal devices. When network services are provided to terminal devices based on SUPI, the network only knows that there is a car, but not who is driving it. With the introduction of user identification, the network can identify the specific user using the car, facilitating the provision of differentiated services for different users. For example, some users may require high-bandwidth, low-latency network services for assisted driving. Based on these needs, the network can provide these users with high-bandwidth, low-latency network services. For other users who do not require assisted driving, the network can provide services that guarantee minimum communication capabilities.

[0082] In the embodiments of the present application, since the network identifies the user based on the acquired user identifier and provides the corresponding network service to the user, the person actually using the terminal device and the user logging into the terminal device are not completely equivalent on the network side. For example, if the same person logs into the terminal device using different user identifiers at different times, the network will consider different users to be logging into the terminal device based on the different user identifiers.

[0083] 2. Establishment and release of PDU session:

[0084] Currently, after a terminal device requests to establish a PDU session with the core network, the core network will query the terminal device's subscription data based on the terminal device's SUPI and decide whether to establish a PDU session for the terminal device. The PDU session establishment process mainly includes the following steps:

[0085] 1. The terminal device sends a session establishment request message to the access and mobility management function (AMF), which carries the session identifier (PDU Session ID) and request type.

[0086] 2.AMF finds the appropriate session management function (SMF).

[0087] 3. The AMF sends a session establishment request to the SMF, which carries the SUPI of the terminal device and some parameters requested by the terminal device, such as DNN, S-NSSAI, etc. Since the SMF is responsible for establishing the session management (SM) context of the session, the session establishment request can also be called a session SM context establishment request, which is used to request the establishment of the context corresponding to the session.

[0088] 4. The SMF queries the contract data of the terminal device and determines whether a PDU session can be established based on the contract data of the terminal device. The SMF can compare the parameters requested by the terminal device in the session establishment request with the corresponding parameters in the contract data of the terminal device to see if they are the same. If they are the same, the PDU session can be established. If they are different, the PDU session cannot be established.

[0089] 5. SMF sends a response to the session establishment request to AMF. If SMF accepts AMF's session establishment request, SMF creates an SM context (SM Context) for the session and includes the SM Context ID in the response message returned to AMF. If SMF does not accept AMF's session establishment request, the response message returned to AMF includes the reason for rejection.

[0090] 6 (Optional Step). The SMF determines whether secondary authentication is required based on the SM policy associated with the DN. If the session request type is Existing PDU Session or Emergency Request, this step is skipped.

[0091] 7. If the PDU session uses dynamic policy and charging control (PCC) rules, the SMF needs to select an appropriate policy control function (PCF).

[0092] 8.SMF performs SM policy association process.

[0093] 9. SMF selects a user plane function (UPF) and assigns an IP address to the PDU session.

[0094] 10.SMF sends relevant information of the PDU session to the UE, including the PDU session identifier, control plane tunnel information (N3 tunnel information), etc.

[0095] Currently, the release of a PDU session can be triggered in the following situations:

[0096] The terminal device triggers the release of the PDU session when the terminal device deregisters.

[0097] The PCF triggers the release of the PDU session due to reasons such as the user reaching the spending limit.

[0098] AMF triggers the release of the PDU session due to reasons such as the discovery that the session status reported by the terminal device does not match the session status saved by AMF.

[0099] The radio access network (RAN) triggers the release of the PDU session due to reasons such as all quality of service (QoS) flows of the PDU session being released.

[0100] The SMF triggers the release of the PDU session due to reasons such as failure of the secondary authentication result of the terminal device and change of the contract information of the terminal device identified by the unified data management (UDM).

[0101] The scenarios of establishing and releasing PDU sessions described above do not introduce user identification. The network side establishes a PDU session for the terminal device. After introducing the user identification, the network side can establish a corresponding session for the user based on the user identification, or release the corresponding session for the user.

[0102] In the scenario where user identification is introduced and the network side can establish a session for the user, since the number of sessions that the terminal device can establish is limited, after the user who logs into the terminal device changes, if the PDU session established for the user who originally logged into the terminal device (hereinafter referred to as the old user) cannot be released in time, it may limit the number of PDU sessions established for the new user, or even make it impossible to establish a PDU session for the new user. Therefore, after the user who logs into the terminal device changes, in order to ensure that the establishment of the PDU session for the new user is not affected, the network side needs to release the PDU session established for the old user in a timely manner. However, there is currently no process for releasing the session of the old user after the new user logs in. Based on this problem, the embodiments of the present application provide a session management method, device and readable storage medium, which can trigger the release of the session established for the old user after the new user logs into the terminal device.

[0103] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Among them, in the description of the present application, unless otherwise specified, " / " indicates that the objects associated before and after are in an "or" relationship. For example, A / B can represent A or B; "and / or" in the present application is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. At the same time, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0104] In the embodiment of the present application, "indication" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. The information indicated by a certain information (such as the first indication information or the second indication information below) is called information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated, such as but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. The information to be indicated can also be indirectly indicated by indicating other information, wherein the other information and the information to be indicated have an association relationship. It is also possible to indicate only a part of the information to be indicated, while the other parts of the information to be indicated are known or agreed in advance. For example, the indication of specific information can be achieved by means of the arrangement order of each piece of information agreed in advance (such as specified in the protocol), thereby reducing the indication overhead to a certain extent. At the same time, the common parts of each piece of information can also be identified and indicated uniformly to reduce the indication overhead caused by indicating the same information separately.

[0105] In addition, the specific indication method can also be various existing indication methods, such as but not limited to the above-mentioned indication methods and various combinations thereof. The specific details of the various indication methods can be referred to the prior art and will not be repeated herein. As can be seen from the above, for example, when it is necessary to indicate multiple information of the same type, there may be a situation where the indication methods for different information are different. In the specific implementation process, the required indication method can be selected according to specific needs. The embodiment of the present application does not limit the selected indication method. In this way, the indication method involved in the embodiment of the present application should be understood to cover various methods that can enable the party to be indicated to obtain the information to be indicated.

[0106] It should be understood that the information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately, and the sending period and / or sending time of these sub-information can be the same or different. The specific sending method is not limited in the embodiments of this application. The sending period and / or sending time of these sub-information can be predefined, for example, predefined according to a protocol, or can be configured by the transmitting device by sending configuration information to the receiving device.

[0107] In an embodiment of the present application, "pre-definition", "pre-defined", "pre-configured" or "pre-configured" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in the device. For example, it can be burned into the device when the device leaves the factory. The embodiment of the present application does not limit its specific implementation method. Among them, "saving" can mean saving in one or more memories. The one or more memories can be set separately or integrated in an encoder or decoder, a processor, or a communication device. The one or more memories can also be partially set separately and partially integrated in a decoder, a processor, or a communication device. The type of memory can be any form of storage medium, which is not limited by the embodiment of the present application.

[0108] The "protocol" involved in the embodiments of the present application may refer to a protocol family in the communication field, a standard protocol with a similar protocol family frame structure, or a related protocol used in future communication systems. The embodiments of the present application do not make specific limitations on this.

[0109] In the embodiments of the present application, descriptions such as "when...", "in the case of...", "if" and "if" all mean that the device will perform corresponding processing under certain objective circumstances. It does not limit the time, nor does it require the device to perform judgment actions when implemented, nor does it mean that there are other limitations.

[0110] In the embodiment of the present application, "sending information to... (taking the first network element as an example)" can be understood as the destination end of the information being the first network element. This can include sending information to the first network element directly or indirectly. "Receiving information from... (taking the first network element as an example)" can be understood as the source end of the information being the first network element, which can include receiving information from the first network element directly or indirectly. The information may be processed as necessary between the source end and the destination end of the information transmission, such as format changes, etc., but the destination end can understand the valid information from the source end. Similar expressions in this application can be understood similarly and will not be repeated here.

[0111] The technical solution provided in this application can be used for various communication systems, which may be a third generation partnership project (3GPP) communication system, for example, a 4th generation (4G) mobile communication system, a long term evolution (LTE) system, a 5th generation (5G) mobile communication system and its evolution system, a non-terrestrial network (NTN) system, a multiple-input multiple-output (MIMO) system, a vehicle to everything (V2X) system, a system of LTE and new radio (NR) hybrid networking, or a device to device (D2D) system, a machine to machine (M2M) communication system, an Internet of Things (IoT), and other communication systems, such as future mobile communication systems. In addition, the term "system" and "network" can be used interchangeably.

[0112] It should be noted that the network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field can know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0113] Figure 1 shows a possible, non-limiting system diagram. As shown in Figure 1, communication system 1000 includes RAN 100 and core network (CN) 200. RAN 100 includes at least one RAN node (e.g., 110a and 110b in Figure 1, collectively referred to as 110) and at least one terminal device (e.g., 120a-120j in Figure 1, collectively referred to as 120). RAN 100 may also include other RAN nodes, such as wireless relay devices and / or wireless backhaul devices (not shown in Figure 1). Terminal device 120 is wirelessly connected to RAN node 110. RAN node 110 is wirelessly or wiredly connected to core network 200. The core network devices in core network 200 and RAN node 110 in RAN 100 may be different physical devices, or they may be the same physical device that integrates core network logical functions and radio access network logical functions.

[0114] As shown in FIG. 1 , optionally, the communication system 1000 may further include the Internet 300 .

[0115] RAN 100 may be a 3GPP-related cellular system, such as a 4G or 5G mobile communication system, or a future-oriented evolutionary system. RAN 100 may also be an open access network (O-RAN or ORAN), a cloud radio access network (CRAN), or a wireless fidelity (WiFi) system. RAN 100 may also be a communication system that integrates two or more of the above systems.

[0116] The terminal device 120 in the embodiments of the present application may also be referred to as a terminal, user equipment (UE), mobile station (MS), or mobile terminal, and refers to a device that provides voice and / or data connectivity to a user, such as a handheld device or vehicle-mounted device with wireless connectivity. The terminal device can be widely used in various scenarios, such as vehicle-to-everything (V2X) communication, machine-type communication (MTC), IoT, virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical surgery, smart grid, smart home, smart office, smart bracelet, and smart city. Currently, some examples of terminal devices include mobile phones, tablet computers, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, and smart home devices. The embodiments of the present application do not limit the device form factor of the terminal device.

[0117] RAN node 110, sometimes also referred to as access network equipment, RAN entity, or access node, constitutes part of the communication system and facilitates wireless access for terminal devices. Multiple RAN nodes 110 in communication system 1000 can be of the same type or different types. In some scenarios, the roles of RAN node 110 and terminal device 120 are relative. For example, network element 120i in Figure 1 can be a helicopter or drone, which can be configured as a mobile base station. For terminal device 120j accessing RAN 100 via network element 120i, network element 120i is a base station; however, for base station 110a, network element 120i is a terminal device. RAN node 110 and terminal device 120 are sometimes referred to as communication devices. For example, network elements 110a and 110b in Figure 1 can be understood as communication devices with base station functionality, and network elements 120a-120j can be understood as communication devices with terminal device functionality.

[0118] In one possible scenario, a RAN node may be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a base station in a future mobile communication system, or an access node in a WiFi system. A RAN node may be a macro base station (such as 110a in Figure 1 ), a micro base station or an indoor station (such as 110b in Figure 1 ), a relay node or a donor node, or a wireless controller in a CRAN scenario. Alternatively, a RAN node may be a server, a wearable device, a vehicle, or an onboard device. For example, the access network device in vehicle-to-everything (V2X) technology may be a roadside unit (RSU).

[0119] In another possible scenario, multiple RAN nodes collaborate to assist the terminal in achieving wireless access, and different RAN nodes respectively implement part of the functions of the base station. For example, the RAN node can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or they can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0120] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0121] All or part of the functions of the RAN node in the embodiments of the present application may also be implemented through software functions running on hardware, or through virtualized functions instantiated on a platform (e.g., a cloud platform). The RAN node in the present application may also be a logical node, logical module, or software that can implement all or part of the RAN node functions.

[0122] The core network device in the embodiment of the present application refers to a device in the core network that provides service support for the terminal device. Examples of some core network devices include: AMF entity, SMF entity, etc., which are not listed here one by one.

[0123] In an embodiment of the present application, an entity may also be referred to as a network element or a functional entity. For example, an AMF entity may also be referred to as an AMF network element or an AMF functional entity. For another example, an SMF entity may also be referred to as an SMF network element or an SMF functional entity, etc.

[0124] Figure 2 is a schematic diagram of a 5G network architecture based on a service-oriented interface applicable to this application. As shown in Figure 2, the network architecture mainly includes the following network functions and entities: terminal equipment, RAN node, UPF, data network (DN) / authentication, authorization, accounting (AAA) server, AMF, SMF, PCF, network repository function (NRF), unified data management function (UDM), and authentication server function (AUSF).

[0125] The following is a brief introduction to the network functions and entities mainly included in the network architecture shown in Figure 2.

[0126] AMF: Mainly responsible for performing registration, connection, reachability and mobility management, providing session management message transmission channels for terminal devices and SMF, and providing authentication and authorization functions for user access. It is the access point between terminal devices and the wireless core network control plane.

[0127] SMF: Mainly responsible for session management, such as session establishment, modification, and release.

[0128] UDM: Mainly responsible for contract management, access authorization, authentication information generation, etc.

[0129] UPF: User plane function, mainly responsible for user data processing (forwarding, receiving, billing, etc.).

[0130] DN: A carrier network used to provide services to terminal devices, such as Internet Protocol (IP) Multimedia Service (IMS) and the Internet.

[0131] The terminal device and RAN node in FIG2 can refer to the above description of the terminal device 120 and the RAN node 110 in the communication system shown in FIG1 , which will not be elaborated here.

[0132] The main functions of other network elements in the architecture shown in Figure 2, such as PCF network element, NRF network element, AUSF network element, or AAA server, can refer to existing protocols and will not be expanded here.

[0133] Figure 2 also illustrates the interactions between various network functions and entities, as well as their corresponding interfaces. As shown in Figure 2, a terminal device accesses the 5G network through a RAN node. Optionally, the terminal device communicates with the AMF through the N1 interface. The RAN node communicates with the AMF through the N2 interface (N2). The RAN node communicates with the UPF through the N3 interface (N3). The SMF communicates with the UPF through the N4 interface (N4), and the UPF accesses the DN or communicates with the AAA server through the N6 interface (N6). Furthermore, the network functions shown in Figure 2, such as the AMF, SMF, NRF, PCF, UDM, or AUSF, interact using service-based interfaces. For example, the service-based interface provided by the AMF is Namf; the service-based interface provided by the SMF is Nsmf; the service-based interface provided by the NRF is Nnrf; the service-based interface provided by the UDM is Nudm; the service-based interface provided by the PCF is Npcf; and the service-based interface provided by the AUSF is Npcf.

[0134] The following describes the session management method provided in the embodiment of the present application in conjunction with Figures 1 and 2.

[0135] It can be understood that in the embodiments of the present application, the names of each network element, the message names between each network element, the names of each parameter, or the names of each information are only examples. In other embodiments, they may also be other names. The method provided in this application does not make specific limitations on this.

[0136] It is understood that in the embodiments of the present application, each network element or entity may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples, and the embodiments of the present application may also perform other operations or variations of various operations. In addition, the steps may be performed in a different order than those presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed.

[0137] As shown in Figure 3, a session management method is provided in an embodiment of the present application. In Figure 3, a first network element or a terminal device is used as the execution subject of the session management method to illustrate the method, but the present application does not limit the execution subject of the illustration. For example, the first network element in Figure 3 can also be a module applied to the first network element, such as a chip, a chip system, or a processor, or a logical node, a logical module, or software that can realize all or part of the functions of the first network element; the terminal device in Figure 3 can also be a module applied to the terminal device, such as a chip, a chip system, or a processor, or a logical node, a logical module, or software that can realize all or part of the functions of the terminal device.

[0138] As shown in FIG3 , the session management method includes the following steps:

[0139] S301: After a first user logs in to a terminal device, a first network element or the terminal device obtains an identifier of the first user.

[0140] S302: The first network element or terminal device determines to release one or more first sessions based on the first user identifier, wherein the one or more first sessions belong to at least one second session established by a second user through the terminal device, and the second user logged into the terminal device before the first user.

[0141] S303. The first network element or terminal device triggers the release of one or more first sessions.

[0142] In the embodiment of the present application, the first network element is a core network element. Exemplarily, the first network element may be an AMF network element or an SMF network element.

[0143] Based on the session management method provided in the embodiment of the present application, after a new user logs in to the terminal device, the release of the session established for the old user can be triggered in time to ensure that the session established for the new user will not be affected.

[0144] The following is an introduction to S301.

[0145] In S301, the first user has a corresponding user identifier (hereinafter referred to as the identifier of the first user). After the first user logs in to the terminal device, the terminal device can obtain the identifier of the first user.

[0146] In an embodiment of the present application, when a user logs in to a terminal device, they can log in using a user ID, or they can log in using the default mode. If the user logs in to the terminal device using the user ID, the terminal device can obtain the user ID. If the user logs in using the default mode, the terminal device cannot obtain the user ID. Based on the absence of the user ID, the terminal device can assume that the person using the terminal device at this time is not a user who has signed a contract with the network (e.g., an operator network, a third-party network, etc.), or in other words, a user who has not signed a contract with the network has logged in to the terminal device.

[0147] The embodiments of the present application do not limit the specific method for a user to log in to a terminal device. For example, a user can log in to a terminal device by logging in to an account. In this method, accounts can be divided into "user accounts" and "visitor accounts". If a user logs in to a "user account", the terminal device can obtain a user identifier based on the "user account" (the user identifier can be the user name, mobile phone number, etc. used by the user to log in to the user account, or the user account is the user identifier). If the user logs in to a "visitor account", the terminal device cannot obtain the user identifier, and it can be considered that the user has logged in through the default mode.

[0148] For another example, the terminal device may store a mapping relationship between the user's physical feature information (such as face, fingerprint, etc.) and the user's user ID. When the user wants to use the terminal device, the terminal device may scan the user's physical feature information and query the corresponding user ID. If the corresponding user ID is found, it can be considered that the user has logged in using the user ID. If the corresponding user ID is not found, it can be considered that the user has logged in using the default mode.

[0149] For another example, the terminal device may store information about the user's other devices (such as Bluetooth headphones, sports bracelets, etc.) and a mapping relationship between the user's user identifier. After the user's other devices establish a connection with the terminal device (for example, a connection may be established through Bluetooth technology, WiFi technology, etc., which is not specifically limited in the present embodiment), the terminal device may query the user's user identifier based on the information of the other devices. If a corresponding user identifier is found, it can be considered that the user has logged in through the user identifier. If no corresponding user identifier is found, it can be considered that the user has logged in through the default mode.

[0150] In addition, for security reasons, in one possible case, the terminal device may only allow the user to log in to the terminal device through the user identification. In this case, if the terminal device cannot obtain the user identification of the user who wants to use the terminal device, the terminal device may refuse the user to log in to the terminal device.

[0151] The embodiments of the present application do not limit the specific implementation of the terminal device obtaining the user's identification. The following introduces several possible implementations provided by the embodiments of the present application.

[0152] In a possible implementation, the terminal device may obtain the user's identifier through a connection with other devices of the user. For example, the user's identifier is carried in a message sent by other devices of the user to the terminal device.

[0153] In another possible implementation, the terminal device can obtain the user's identification through the user inputting information of the terminal device. For example, when the first user logs in to the terminal device through an account, the user can enter information such as the user name and mobile phone number as the first user's identification.

[0154] In another possible approach, the terminal device may obtain partial information that can constitute the user's identification through a connection between the user's other devices and the terminal device, or through information input by the user, and combine this partial information with other information on the terminal device to determine the combined information as the first user's identification. Optionally, the terminal device may combine the obtained information that can uniquely identify the user with other information on the terminal device. (In other words, the information that can uniquely identify the user can be combined with other information on the terminal device to form partial information that can serve as the user's identification.)

[0155] For example, after the user enters an account with the username 123456, the terminal device obtains 123456 and determines it as information used to uniquely identify the user. The terminal device then determines the terminal device's home public land mobile network (HPLMN) identifier and / or route identification (RID) as routing information, and then combines them to obtain 123456@5gc.RID.HPLMN ID in the network access identifier (NAI) format, and uses 123456@5gc.RID.HPLMN ID as the user's identifier.

[0156] Optionally, some or all of the information included in the user's identification can be encrypted or otherwise protected. For example, after a terminal device receives a user's input username, it can encrypt the username and combine the encrypted information with other information on the terminal device to obtain the user's identification. For another example, after a terminal device receives a user's mobile phone number, it can encrypt the mobile phone number and use the encrypted mobile phone number as the user's identification.

[0157] After the terminal device obtains the identifier of the first user, it can enable the core network to obtain the identifier of the first user.

[0158] In addition, optionally, the terminal device can generate indication information indicating the user's login mode, which can instruct the user to log in to the terminal device through the user ID, or instruct the user to log in to the terminal device through the default mode, and enable the core network to obtain the indication information, so that the core network can know whether the user logs in to the terminal device through the default mode or through the user ID.

[0159] Alternatively, the terminal device and the network may pre-agreed (or pre-defined by a protocol, pre-configured, etc.) that, when a specific message sent by the terminal device to a core network element does not carry a user identifier, it indicates that the user logged into the terminal device using a default mode. When the specific message carries a user identifier, it indicates that the user logged into the terminal device using the user identifier. In this case, the user identifier may also be considered to be indicative information instructing the user to log into the terminal device using the user identifier. For example, the specific message may be the third message described below.

[0160] In an embodiment of the present application, the indication information indicating the user's login mode can be implemented in a variety of ways. For example, it can be bit indication information or enumeration-type indication information, which is not limited in the embodiment of the present application. For example, when the indication information indicating the user's login mode is bit indication information, the indication information can indicate the user's login mode through the bit value. For example, when the bit is 0, it indicates that the user logs in through the user identification, and when the bit is 1, it indicates that the user logs in to the terminal device through the default mode. For another example, when the indication information indicating the user's login mode is enumeration-type indication information, the character string "Default" can be used to indicate that the user logs in to the terminal device through the default mode.

[0161] The embodiments of the present application do not limit the specific implementation of the terminal device enabling the core network to obtain the user's identification. The following introduces several possible implementation methods provided by the embodiments of the present application.

[0162] Method 1: Enable the core network to obtain the user's identity through a user registration process or an authentication process for the user identity. The terminal device sends a non-access stratum (NAS) message to the core network element, and the NAS message includes the identity of the first user. Exemplarily, the NAS message can be a user registration request message or a user authentication request message. Wherein, if the NAS message is a user registration request message, the terminal device can send the NAS message to the AMF network element. If the NAS message is a user authentication request message, the terminal device can send the NAS message to the network element used for authentication (such as an AUSF / AMF / AAA server network element), and the network element used for authentication can authenticate the user identity based on the user identity. Optionally, if the network element used for authentication is not an AMF network element, the network element used for authentication can send an authentication result response message to the AMF network element, and the authentication result response message includes the authentication result and the user identity.

[0163] Optionally, the NAS message may further include the SUPI of the terminal device.

[0164] Method 2: Enable the core network to obtain the user's identity through the session establishment process. The terminal device sends a session management (SM) message to the core network element (such as the AMF network element or SMF network element). The SM message includes the user's identity. For example, the SM message can be a PDU session establishment request message.

[0165] In addition, in the process of the terminal device registering with the network, the AMF network element can obtain the SUPI of the terminal device, and establish a next generation application protocol (NGAP) connection between the terminal device and the AMF network element. The subsequent access network device will add an NGAP identifier to the header of the message (one terminal device corresponds to one NGAP identifier) ​​before sending the message from the terminal device to the AMF network element, and then send the message to the AMF network element. After receiving the message, the AMF network element can determine which terminal device the message comes from based on the NGAP identifier (such as NGAP ID) without opening the message. Therefore, based on this process, if the user who logs in to the terminal device changes, the AMF network element can also determine that the terminal device logged in by the new user (the first user in the embodiment of the present application) and the terminal device logged in by the old user (the second user in the embodiment of the present application) are the same terminal device based on the NGAP identifier in the message header from the terminal device.

[0166] The above describes the terminal device obtaining the first user's identifier. If the execution subject of S302-S303 is the first network element, that is, the first network element determines and triggers the release of one or more first network elements, then in S301, the first network element can obtain the first user's identifier.

[0167] The first network element may receive the identifier of the first user from the terminal device. For example, the terminal device may send a third message carrying the identifier of the first user to the first network element. Exemplarily, the third message may be used to request that the user corresponding to the first user identifier be registered with the network; or the third message may be used to request that the network authenticate the first user identifier; or the third message may be used to request that a session be established for the user corresponding to the second user identifier. For details, please refer to the above-mentioned method 1 or method 2.

[0168] Alternatively, the first network element may receive the identifier of the first user from other core network elements. For example, referring to the above-mentioned method 1, if the first network element is an AMF network element, other core network elements that authenticate the first user may send an authentication result response message to the first network element, and the authentication result response message includes the identifier of the first user and the authentication result corresponding to the identifier of the first user. For another example, if the first network element is an SMF network element, the AMF network element may send a fifth message carrying the identifier of the first user to the first network element, and the fifth message is used to request the establishment of a context for the session corresponding to the identifier of the first user. For example, the request message may be Nsmf_PDUSession_CreateSMContext Request.

[0169] The following is a detailed introduction to S302.

[0170] The one or more first sessions belong to at least one second session established by a second user through a terminal device, and the second user logs into the terminal device before the first user.

[0171] It is understandable that since the second user has already logged into the terminal device before the first user logs into the terminal device, the second user is an "old user" relative to the first user, who is a "new user." The at least one second session is a session established by the network for the second user after the second user logs into the terminal device.

[0172] When the second user logs in to the terminal device, he or she may log in to the terminal device through the user identification of the second user (hereinafter referred to as the identification of the second user), or may log in to the terminal device through a default mode.

[0173] After the second user logs in to the terminal device, the terminal device may enable the core network to obtain first indication information, where the first indication information is used to instruct the second user to log in to the terminal device using a default mode, or to instruct the second user to log in to the terminal device using the second user's identifier (for example, the first indication information may be the second user's identifier). Alternatively, the terminal device may also use other methods to inform the core network of the method in which the second user logs in to the terminal device. For details, please refer to the above description of S301, which will not be elaborated here.

[0174] Optionally, if the execution subject of S302-S303 is the first network element, the first network element can also learn the method in which the second user logs into the terminal device. For example, the first network element can obtain the first indication information.

[0175] The embodiments of the present application do not limit the specific implementation of the terminal device enabling the core network to obtain the first indication information, and the specific implementation of the first network element obtaining the first indication information. For example, you can refer to the above introduction to the implementation of the terminal device enabling the core network to obtain the user's identification, and the implementation of the first network element obtaining the first user's identification.

[0176] Optionally, after the first network element obtains the first indication information, it may also record (or save, store, etc.) the first indication information. The embodiment of the present application does not limit the data structure in which the first network element records the first indication information. For example, it may be recorded in the description information of the terminal device. In one possible implementation, based on the difference in the first network element, the first network element may record the first indication information in different data structures. For example, if the first network element is an AMF network element, the first network element may record the first indication information in the context of the terminal device. If the first network element is an SMF network element, the first network element may record the first indication information in the SM context of the second session. In another possible implementation, based on the different ways in which the first network element obtains the first indication information, the first network element may record the first indication information in different data structures. For example, if the first network element receives the first indication information through an authentication result response message, the first network element may record the first indication information into the terminal device-level information included in the context of the terminal device. If the first network element receives the first indication information through a session establishment request message, the first network element may record the first indication information into the session-level information included in the context of the terminal device.

[0177] For one or more first sessions belonging to at least one second session, in a possible implementation, each session in the at least one second session is a first session, that is, the first network element or terminal device determines to release all second sessions.

[0178] In another possible implementation, the first network element or terminal device selects one or more second sessions from at least one second session as the one or more first sessions to be released. This embodiment of the present application does not limit the specific implementation of selecting a second session as the first session. For example, a second session can be randomly selected from at least one second session as the first session. For another example, a second session that cannot be reused by the first user can be selected from the second sessions as the first session. This solution is described in detail below and is not elaborated here.

[0179] In particular, when the first network element or terminal device selects one or more first sessions from at least one second session as the first session, it may also select all the second sessions as the first session.

[0180] The following describes how the first network element determines to release one or more first sessions according to the first user identifier, and how the terminal device determines to release one or more first sessions according to the first user identifier.

[0181] Scenario 1: The first network element determines to release one or more first sessions according to the identifier of the first user.

[0182] In a possible implementation, the first network element may identify, based on the identifier of the first user, that a user logging into the terminal device has changed, and then determine to release one or more first sessions.

[0183] The embodiment of the present application does not limit the manner in which the first network element identifies a change in the user who has logged into the terminal device. In one possible implementation, after the second user logs into the terminal device, the first network element can obtain the first indication information. After the first user logs into the terminal device and the first network element obtains the identifier of the first user, the first network element can determine that the second user is not the same user as the first user by comparing the first indication information with the identifier of the first user, that is, it determines that the user who has logged into the terminal device has changed. For example, assuming that the first indication information indicates that the second user logs into the terminal device through the default mode, the first network element can determine that the first user logs into the terminal device through the user identifier based on the identifier of the first user, and then it can be determined that the first user and the second user are not the same user. Assuming that the first indication information indicates that the second user logs into the terminal device through the identifier of the second user, the first network element can determine whether the identifier of the second user is different from the identifier of the first user. If they are different, it can be determined that the first user and the second user are not the same user.

[0184] Furthermore, the first network element determines to release all or part of the second session. For example, the first network element may pre-configure a rule to release all sessions established by the old user (the second user in this embodiment of the application) through the terminal device after recognizing that the user who logged in to the terminal device has changed.

[0185] Optionally, the first network element may select a second session that cannot be reused by the first user from the second sessions and determine it as the released second session, ie, the first session. This optional solution is described in detail below.

[0186] Step 1: The first network element obtains the user information or contract data corresponding to the identifier of the first user (in an embodiment of the present application, the contract data corresponding to the identifier of the user may also be referred to as the user contract data corresponding to the identifier of the user). For example, the first network element may send a first message to other network elements, wherein the first message includes the identifier of the first user, and the first message is used to request the user information (user profile) or user contract data corresponding to the identifier of the first user from other network elements. For example, the other network element may be a UDM network element, and the first message may be a Nudm_SDM_Get Request message. After receiving the first message, the other network elements query the user information or user contract data corresponding to the identifier of the first user based on the identifier of the first user, and send the user information or user contract data corresponding to the identifier of the first user found to the first network element.

[0187] Step 2: The first network element determines the second session that cannot be reused by the first user in the second session as the first session based on the user information or user subscription data corresponding to the first user's identifier and the relevant information of the second session.

[0188] The embodiment of the present application does not impose any specific limitation on determining the second session that cannot be reused by the first user based on the user information or user subscription data corresponding to the identifier of the first user.

[0189] In this possible solution, the first network element can determine the parameters subscribed by the first user's identifier based on the user information or user contract data corresponding to the first user's identifier, and the parameters are used to determine the session. For example, the parameters may include at least one of the following: data network name (DNN) or single network slice selection assistance information (S-NSSAI) information. The first network element determines, based on the above-mentioned parameters subscribed by the first user's identifier and the above-mentioned parameters corresponding to each second session in at least one second session, a second session whose corresponding parameters are different from the parameters subscribed by the first user's identifier as a second session that cannot be reused by the first user, that is, as a first session.

[0190] For example, assuming that the first user's identifier subscribes to DNN-1, DNN-2, and S-NSSAI-1, the DNN corresponding to the PDU session-1 established for the second user is DNN-1, and the slice uses S-NSSAI-2. The DNN corresponding to the PDU session-2 established for the second user is DNN-2, and the slice uses S-NSSAI-1. Then, by comparing the parameters subscribed by the first user's identifier, the parameters corresponding to PDU session-1, and the parameters corresponding to PDU session-2, the first network element can determine that PDU session-1 cannot be reused by the first user, PDU session-2 can be reused by the first user, and further determine to release PDU session-1.

[0191] In another possible implementation, after receiving a sixth message from the terminal device requesting to release the session, the first network element may determine to release one or more first sessions based on the first user identifier or the second user identifier carried in the sixth message. For example, the sixth message may be a PDU session release request message.

[0192] Among them, the first network element can determine which sessions to release in a variety of ways. For example, the first network element can pre-agree with the terminal device (or pre-define by protocol, pre-configure, etc.) which sessions the first network element should release when the sixth message carries the user identifier. For example, it can be pre-configured that when the sixth message carries the identifier of the second user, all second sessions are released (that is, each second session is a first session). For another example, it can be pre-configured that when the sixth message carries the identifier of the first user, one or more second sessions are released. Among them, if the first network element determines to release one or more second sessions based on the identifier of the first user carried in the sixth message, the embodiment of the present application does not limit the specific implementation of the first network element determining which second sessions to release. For example, the first network element can determine the number of second sessions to be released based on the load of the terminal device. For another example, the first network element can determine the session in the second session that cannot be reused by the first user as the first session based on the identifier of the first user carried in the request message. For details, please refer to the above introduction and will not be expanded here.

[0193] Among them, the terminal device sends the sixth message to the first network element, which can be triggered by the first user logging into the terminal device, or it can be triggered by the terminal device identifying a change in the user logging into the terminal device, or it can be triggered based on other conditions, and the embodiments of the present application do not limit this.

[0194] Scenario 2: The terminal device determines to release one or more first sessions according to the identifier of the first user.

[0195] In this scenario, the terminal device may identify, based on the identifier of the first user, that a user who logs into the terminal device has changed, and then determine to release one or more first sessions.

[0196] When a change in the user logging into the terminal device is identified, after the second user logs into the terminal device, the terminal device can obtain and record the first indication information. After the first user logs into the terminal device, the terminal device can obtain the identification of the first user and compare the first indication information with the identification of the first user to determine that the first user and the second user are not the same user. For details, please refer to the introduction to scenario one above, which will not be elaborated here.

[0197] In this scenario, the terminal device may determine to release all or part of the second session. For example, the terminal device may be pre-configured to release all sessions established by the old user through the terminal device after recognizing a change in the user logged into the terminal device.

[0198] The following is an introduction to S303.

[0199] If, in S302, the first network element determines to release one or more first sessions, then in S303, the first network element also triggers the release of the one or more first sessions. If, in S302, the terminal device determines to release one or more first sessions, then in S303, the terminal device also triggers the release of the one or more first sessions.

[0200] Based on this, the following is divided into the above scenario one and the above scenario two, and the first network element triggering the release of one or more first sessions and the terminal device triggering the release of one or more first sessions are introduced in detail.

[0201] Scenario 1: The first network element triggers the release of the first session.

[0202] The first network element may trigger the release of the first session by interacting with other core network elements. In one possible implementation, the first network element may send a fourth message to the other core network elements, the fourth message including identification information for identifying one or more first sessions, requesting the release of one or more second sessions. The other network elements may release the one or more first sessions based on the fourth message.

[0203] For example, assuming that the first network element is an AMF network element, the first network element can request the SMF network element to release the first session. Specifically, the first session can send an SM context release request message to the SMF network element. For example, the message can be an Nsmf_PDUSession_ReleaseSMContext Request message, which carries information indicating the first session, such as the identification information of the first session or the identification information of the SM context of the first session. Furthermore, the SMF network element can trigger the release of the N4 session by sending an N4 session release request message to the UPF network element based on the information indicating the first session. For example, the message can be an N4session release request message, which includes the identification of the N4 session to be released. The SMF network element releases the IP address / IP prefix associated with the first session and all resources and contexts associated with the N4 session by interacting with the UPF network element. After releasing the SM context of the first session, the SMF network element can send an SM context release request response to the first network element to inform the first network element that the SM context of the first session has been released. Accordingly, the first network element releases the relevant information of the first session that it has saved, such as the identification information of the SMF network element associated with the first session (such as SMF ID), etc. The SMF network element can also inform the UDM network element that the first session has been released, and instruct the UDM network element to remove the association between the SMF ID and DNN stored in the UDM network element and the ID of the first session. For example, the SMF network element can send a Nudm_UECM_Deregistration Request / Response message to the UDM network element, which carries the ID and DNN of the first session.

[0204] For another example, assuming that the first network element is an SMF network element, how the first network element triggers the release of the first session can be referred to the above introduction and will not be elaborated here.

[0205] Scenario 2: The terminal device triggers the release of the first session.

[0206] After the terminal device determines to release one or more first sessions, it can send a request message to the core network element requesting the release of the session, and the request message carries the identification information of each first session. After the core network element receives the request message, it can release the first session based on the identification information of the first session in the request message. For example, the terminal device can send an SM message to the AMF network element, such as a PDU session release request message, which carries the identification information of the first session. The AMF network element can release the corresponding first session based on the identification information of the first session in the request message. For details, please refer to the above introduction to scenario one, which will not be expanded here.

[0207] The above method embodiments describe a process in which a first network element or terminal device releases one or more first sessions established for an old user after a new user logs into the terminal device. The following describes some optional solutions provided by the embodiments of the present application.

[0208] Optionally, before S301, a core network element (hereinafter referred to as an AMF element) may send a second message to another core network element (hereinafter referred to as an SMF element) to establish a second session. The second message includes the first indication information, and the second message is used to request the establishment of an SM context for the session corresponding to the second user. After receiving the second message, the SMF element may establish an SM context for the corresponding session based on the second message. Exemplarily, the AMF element may send an Nsmf_PDUSession_CreateSMContext Request message to the SMF element, which carries the first indication information.

[0209] Among them, if the first indication information indicates that the second user logs in through the user identifier, the SMF network element can obtain the user information or user contract data corresponding to the second user's identifier, for example, it can request the user information or user contract data corresponding to the second user's identifier from the UDM network element, and based on the user information or user contract data corresponding to the second user's identifier, determine whether a session can be established for the second user. If the first indication information indicates that the second user logs in through the default mode, the SMF network element can query the contract data corresponding to the terminal device, and based on the contract data corresponding to the terminal device, determine whether a session can be established for the second user. Among them, how the SMF network element specifically determines whether a session can be established for the second user based on the user information or user contract data corresponding to the second user's identifier, or based on the contract data corresponding to the terminal device, can refer to the above introduction to the existing PDU session establishment process, or can refer to the existing protocol, and will not be elaborated here.

[0210] Optionally, the second message may further include the SUPI of the terminal device.

[0211] Optionally, if the first network element is an SMF network element, after the user logs in to the terminal device, the terminal device can send a seventh message to the AMF network element, and the seventh message includes the second indication information. The second indication information is used to indicate that the terminal device can be logged in by different users at different times. The seventh message can be SM information, for example, it can be a PDU session establishment request message. After receiving the seventh message, the AMF network element can determine, based on the second indication information, to select the same SMF network element or the SMF network element in the same set when establishing sessions corresponding to different users for the terminal device. Among them, the SMF network elements in the same set can share relevant information of the session, for example, they can share the identification information of the PDU session, the DNN corresponding to the PDU session, and the correspondence between the S-NSSAI. Based on this, when the first network element establishes a session for the first user, since the first network element also established a session for the second user before (or the SMF network element in the same set established a session for the second user), the first network element can recognize that the user who logged in to the terminal device has changed.

[0212] For example, when establishing a session for the second user on the network side, the first network element receives the eighth message from the AMF network element. The eighth message is used to request the establishment of a context for the session corresponding to the second user. The eighth message includes the first indication information and the SUPI of the terminal device. For example, the eighth message may be Nsmf_PDUSession_CreateSMContext Request. After the first user logs in to the terminal device, when establishing a session for the first user on the network side, the first network element also receives the fifth message from the AMF network element. The fifth message is used to request the establishment of a context for the session corresponding to the first user. The fifth message includes the identifier of the first user and the SUPI of the terminal device. The first network element can compare the identifier of the first user carried in the fifth message with the first indication information carried in the eighth message to identify that the user who has logged in to the terminal device has changed.

[0213] The embodiments of the present application do not limit the specific form of the second indication information. For example, the protocol may pre-define that when the type of the seventh message is a certain specific type, it means that the terminal device sending the seventh message can be logged in by different users at different times. In this case, the second indication information may indicate that the type of the seventh message is the specific type. For example, the specific type may be user identities and authentication (UIA). For another example, the protocol may pre-define that when the seventh message carries a user identifier, it means that the terminal can be logged in by different users at different times. In this case, the second indication information may be a user identifier. For another example, the second indication information may be a terminal capability or a terminal type.

[0214] Optionally, if the first network element records the first indication information in the description information of the terminal device after the second user logs into the terminal device, after the first user logs into the terminal device, if the first network element determines to release part of the second session that cannot be reused by the first user, after releasing this part of the second session, the first network element can update the first indication information in the description information of the terminal device that is associated with the information of the remaining second session (i.e., the second session that can be reused by the first user) to the identifier of the first user.

[0215] The following assumes that an embodiment of the present application is applied to a 5G system, and introduces a possible, non-restrictive process of the network side establishing a PDU session for the second user after the second user logs into the terminal device, and releasing one or more PDU sessions established for the second user after the first user logs into the terminal device.

[0216] Assuming that the execution subject of S301-S303 is the first network element, the first network element is the AMF network element, and the terminal device is the UE, in this scenario, the network side establishes a PDU session for the second user after the second user logs in to the UE, and releases one or more PDU sessions established for the second user after the first user logs in to the UE. A possible, non-limiting process is shown in Figure 4, including the following steps:

[0217] S401. A second user logs in to a UE using a default mode or an identifier of the second user: User ID #1 (it will be understood that User ID #1 is an example of an identifier of the second user and does not limit the identifier of the second user). After the second user logs in to the UE, the UE enables the core network to learn that the second user currently logged in to the UE has logged in using the default mode, or enables the core network to learn the identifier of the second user currently logged in to the UE: User ID #1.

[0218] Among them, the UE enables the core network to know that the second user currently logged in to the UE has logged in through the default mode, or enables the core network to know the identifier of the second user currently logged in to the UE: the specific implementation of User ID#1 can refer to the above introduction to S301 and will not be expanded here.

[0219] S402. The AMF network element records the identifier of the second user currently logged in on the UE: User ID#1. For example, the AMF records the identifier in the UE context. A possible specific record format may be a field of "activated user identifier" described as "user identifier that is currently using the UE." Alternatively, the AMF network element records the first indication information, and the first indication information indicates that the second user currently logged in on the UE has logged in through the default mode. For example, the first indication information may be the field default. In addition, optionally, if the second user logs in through the default mode, the AMF network element may also learn that the second user has logged in through the default mode, but does not record the first indication information.

[0220] Among them, the User ID#1 or the first indication information obtained by the AMF network element may be sent by the UE to the AMF network element in S401, or, in S401, after the UE sends an authentication request message carrying the User ID#1 or the first indication information to the network element such as the AUSF or AAA Server used for authentication, the AUSF or AAA Server or other network element carries the User ID#1 or the first indication information in the authentication result response message and sends it to the AMF network element. Alternatively, if in S401, the third message (such as the user registration request message, the user authentication request message, the PDU session establishment request message, etc.) sent by the UE to the AMF network element does not carry the user identifier, the AMF network element may determine that the second user has logged in through the default mode. Optionally, the AMF network element may also generate and record the first indication information. Alternatively, if in S401, the authentication result response message received by the AMF network element does not carry the user identifier, the AMF network element may determine that the second user has logged in through the default mode. Optionally, the AMF network element may also generate and record the first indication information.

[0221] Among them, if the authentication result response message indicates that the authentication is successful, the AMF network element obtains User ID#1 or the first indication information through the authentication result response message, or the AMF obtains User ID#1 or the first indication information through the user registration process, and the AMF network element can record User ID#1 or the first indication information into the terminal device level information in the UE context. If the AMF network element obtains User ID#1 or the first indication information through the PDU session establishment request message, the AMF network element can record User ID#1 or the first indication information into the PDU session level information in the UE context.

[0222] If, in S401, the UE notifies the core network that the second user has logged in via the default mode or the core network of the second user's identifier, User ID#1, via a message other than the PDU Session Establishment Request message, the process shown in FIG4 further includes S402a to trigger subsequent steps. If, in S401, the UE notifies the core network that the second user has logged in via the default mode or the core network of the second user's identifier, User ID#1, via the PDU Session Establishment Request message, the process shown in FIG4 does not need to include S402a.

[0223] S402a: The UE sends a PDU session establishment request message to the AMF network element. The timing of S402 and S402a is not fixed. S402 can occur before or after S402a.

[0224] S403. The AMF network element sends a session SM context establishment request message to the SMF network element. The request message requests establishment of an SM context for the session corresponding to the second user (it can be understood that since the session has not actually been established for the second user at this time, the request message can also be understood as a request to establish a session for the second user). The request message carries the SUPI, or the request message carries the SUPI and User ID#1, or the request message carries the SUPI and the first indication information. Exemplarily, the request message can be Nsmf_PDUSession_CreateSMContext Request.

[0225] Among them, when the request message carries SUPI and the first indication information, or carries SUPI, it indicates that the second user currently logged in to the terminal device is logged in through the default mode, and the SMF needs to establish a PDU session based on the UE's subscription information. When the request message carries SUPI and User ID#1, it indicates that the second user currently logged in to the terminal device is logged in through user identification User ID#1, and the SMF needs to establish a PDU session based on the user information or user subscription data corresponding to User ID#1.

[0226] S404. Based on the information included in the received request message, the SMF network element queries the UDM network element for the UE's contract data, or queries the UDM network element for the user information or user contract data corresponding to User ID#1, and determines whether a PDU session can be established based on the obtained user information or user contract data.

[0227] Specifically, after the SMF network element receives the UE subscription data from the UDM network element, it queries the DNN and S-NSSAI subscribed by the UE from the obtained subscription data to determine whether a PDU session can be established for the second user (since it is determined based on the subscription data corresponding to the UE, it can also be understood as determining whether a PDU session can be established for the UE). Alternatively, after the SMF network element receives the user information or user subscription data corresponding to User ID#1 from the UDM network element, it checks the DNN and S-NSSAI subscribed by User ID#1 from the obtained user information or user subscription data to determine whether a PDU session can be established for the second user.

[0228] S405. If the SMF network element determines that a PDU session can be established, the SMF creates an SM context associated with the PDU session and sends a session SM context establishment request response message to the AMF network element. The response message includes the identifier of the SM context created by the SMF network element for the PDU session (for example, the ID of the SM context). Exemplarily, the response message may be Nsmf_PDUSession_CreateSMContext Response.

[0229] If the session cannot be established, the SMF network element sends a session SM context establishment request response message to the AMF network element indicating that the PDU session is rejected, and the process ends. The response message may include the reason for rejecting the PDU session establishment. For example, the response message may be Nsmf_PDUSession_CreateSMContext Response.

[0230] S406: The core network establishes a PDU session for the second user (i.e., establishes a second session). This may include the following steps (not shown in FIG4 ):

[0231] S4061. The SMF network element determines whether to trigger secondary authentication. If triggered, secondary authentication is performed.

[0232] If the PDU session is established based on the user information or user contract data corresponding to User ID#1, the SMF network element can determine whether a secondary authentication is required for the second user based on whether there is a requirement for secondary authentication of User ID#1 in the user information or user contract data corresponding to User ID#1. Alternatively, the SMF network element can trigger a secondary authentication process for the second user in combination with the SM policy related to the DN. For example, if the SM policy related to the DN accessed by the UE indicates that all session requesters of the DN, such as terminal devices / users, need secondary authentication, the SMF network element triggers the secondary authentication.

[0233] S4062. If the PDU session uses dynamic policy and charging control (PCC) rules, the SMF network element needs to select an appropriate PCF network element.

[0234] S4063. The SMF network element performs the SM policy association process.

[0235] S4064. If the session type of the PDU session is an initial request, the SMF network element allocates a session service continuity (SSC) mode for the PDU session.

[0236] The SMF network element selects the UPF network element. The SMF network element or the UPF network element allocates an IP address for the PDU session, which is used to indicate the IP address associated with the UE end and the PDU session.

[0237] S4065. The SMF network element sends a message to the UE including relevant information of the PDU session, such as the PDU session identifier, control plane tunnel information (N3 tunnel information), etc. The message is used to establish a data transmission tunnel between the UE and the UPF network element.

[0238] After the second session is established, the AMF network element associates the relevant information of the second session, such as DNN, S-NSSAI, etc., with the first indication information / User ID#1 recorded in S402.

[0239] S407 . The first user logs in to the UE using the first user's identifier: User ID#2 (it is understandable that User ID#2 is an example of the first user's identifier and does not constitute a limitation on the first user's identifier).

[0240] The UE enables the core network to learn that the identifier of the user currently logged into the UE is User ID#2. For specific implementation, please refer to the above introduction to S301 and will not be elaborated here.

[0241] Optionally, before the UE enables the core network to learn that the user currently logged into the UE is identified as User ID#2, a deregistration process for the second user may occur. For example, when the second user logs in to the UE based on the user's identifier and completes the offline process by actively logging out / logging out, the deregistration process for the second user will be triggered. In the deregistration process for the second user, the UE sends a NAS message to the AMF network element, which is used to request deregistration. Exemplarily, the NAS message may be a deregistration request (Deregistraiton Request) message, which carries User ID#1, which is used to indicate the user who is performing the deregistration process at this time, that is, to indicate that the user corresponding to User ID#1 no longer accesses the network through this UE. Alternatively, the deregistration process for the second user may not occur. For example, when the UE has not been operated for a long time and enters an idle state, or when the second user logs in to the UE based on the default mode, the deregistration process for the second user will not be triggered.

[0242] The specific deregistration process for users may include the following steps:

[0243] Step 1: The UE sends a NAS message to the AMF network element, which instructs the network to deregister the user. Exemplarily, the message can be a deregistration request (Deregistration Request), including a 5G-globally unique temporary UE Identity (GUTI), a user's identifier, and a deregistration type. For example, the deregistration type can be indicated as user deregistration through the field user unlinked (this field is an example, and the embodiment of the present application does not limit how to indicate the deregistration type, nor does it limit the specific deregistration type).

[0244] Step 2: If the UE has not established a PDU session for the user identity, directly execute step 3. If a PDU session corresponding to the user identity is established, release all PDU sessions corresponding to the user identity, and then execute step 3. Releasing all PDU sessions corresponding to the user identity includes the following steps: the AMF network element sends an SM context release request message to each SMF network element to release the PDU session. Exemplarily, the message is Nsmf_PDUSession_ReleaseSMContext request. The SMF network element interacts with the UPF network element to release the N4 session (for details, please refer to S411 below). The SMF network element sends an SM context release request response to the AMF network element. The response message is used to inform the AMF network element that the SM context of the first session has been released (for details, please refer to S412 below). For example, the message is Nsmf_PDUSession_ReleaseSMContext response. Then, the SMF network element interacts with the PCF network element and calls the SM policy association termination process to delete the PDU session.

[0245] Step 3: The AMF sends a NAS message to the UE, which is a response message to the message sent by the UE in step 1 to instruct the network to deregister the user. For example, the message may be Deregistration Accept.

[0246] Since the core network has established the second session for the second user in S406, if the deregistration process of the second user is triggered, the session of the second user will be released in the deregistration process of the second user. In this case, steps S410 to S414 are skipped.

[0247] S408. The AMF network element obtains User ID#2 based on the process in S407, and based on User ID#2, identifies that the user who logs in to the UE has changed.

[0248] For example, the AMF network element can identify that the user logged into the UE has changed by comparing User ID#2 with User ID#1 / first indication information stored in the UE context.

[0249] S409. The AMF network element determines to release all or part of the session established for the second user (ie, the second session). The second session determined to be released is hereinafter referred to as the first session.

[0250] FIG4 shows two possible implementations of S409: solution a and solution b.

[0251] Solution a: The AMF network element determines the session in the second session that cannot be reused by the first user as the first session to be released.

[0252] The AMF network element sends a subscription data request message to the UDM, such as a Nudm_SDM_Get Request message, which includes User id#2, and is used to request the UDM network element to query the user information or user subscription data corresponding to User id#2. The UDM network element sends the user information or user subscription data corresponding to User id#2 to the AMF network element, for example, by carrying the user information or user subscription data corresponding to User id#2 through a Nudm_SDM_Get Response message. After receiving the user information or user subscription data corresponding to User id#2, the AMF network element determines which PDU sessions cannot be reused by the first user based on the user information or user subscription data corresponding to User id#2 and the existing PDU session related information (i.e., the related information of each second session), such as DNN, S-NSSAI and other information, and determines the PDU sessions that cannot be reused as the first sessions to be released. For specific instructions on how to determine which PDU sessions cannot be reused by the first user, please refer to the above introduction to S302, which will not be elaborated here.

[0253] Solution b: The AMF network element determines each second session as the first session to be released.

[0254] S410. The AMF network element requests the SMF network element to release the PDU session. If all second sessions are released, the AMF network element sends an SM context release request message, such as the Nsmf_PDUSession_ReleaseSMContext Request message. If part of the second sessions are released, the AMF network element sends an SM context update request message, such as the Nsmf_PDUSession_RelaxSMContext Request message. The message carries information indicating the first session that needs to be released, such as the ID of the first session or the ID of the SM context of the first session.

[0255] S411. The SMF network element triggers the release of the N4 session based on the received SM context release request message, and releases the IP address / IP prefix associated with the first session, as well as all resources and contexts associated with the N4 session by interacting with the UPF network element.

[0256] S412. The SMF network element sends an SM context release request response to the AMF network element. This response message is used to inform the AMF network element that the SM context of the first session has been released. After receiving the response message, the AMF network element releases the relevant information of the first session it has saved, such as the ID of the associated SMF network element.

[0257] S413. (Optional step) If the AMF network element determines the session in the second session that cannot be reused by the first user as the first session to be released, and in S402, the AMF network element records User ID#1 or the first indication information into the PDU session-level information in the UE context, the AMF network element may update the User ID#1 or the first indication information in the PDU session-level information included in the UE context to User ID#2.

[0258] S414. The SMF network element notifies the UDM network element that the first session has been released, and instructs the UDM network element to remove the stored association between the SMF ID, DNN, and PDU session ID associated with the first session. For example, the SMF network element may send a Nudm_UECM_Deregistration Request to the UDM network element. This message carries the ID of the first session and the DNN corresponding to the first session. After the UDM network element removes the association, it may send a Nudm_UECM_Deregistration Response message to the SMF network element to notify the SMF network element that the UDM network element has removed the association.

[0259] Assuming that the execution subject of S301-S303 is the first network element, the first network element is the SMF network element, and the terminal device is the UE, in this scenario, the network side establishes a PDU session for the second user after the second user logs in to the UE, and releases one or more PDU sessions established for the second user after the first user logs in to the UE. A possible, non-limiting process is shown in Figure 5, including the following steps:

[0260] S501. A second user logs in to the UE using the default mode or the second user's identifier: User ID#1. After the second user logs in to the UE, the UE sends an SM message to the AMF network element. Exemplarily, the SM message may be a PDU session establishment request message, which includes second indication information. The second indication information is used to indicate that the UE can be logged in by different users at different times. Based on the second indication information, the AMF network element determines to select the same SMF network element or an SMF network element in the same SMF set (SMF Set) when establishing a session for the UE.

[0261] In addition, if the second user logs in to the UE through the default mode, the message may further include first indication information, where the first indication information is used to indicate that the second user has logged in to the UE through the default mode. Alternatively, it may be predefined or pre-agreed that when the message does not include a user identifier, it indicates that the second user has logged in to the UE through the default mode. If the second user logs in to the UE using the second user's identifier: User ID#1, the message may further include User ID#1.

[0262] S502. The AMF network element selects a suitable SMF network element.

[0263] Specifically, the AMF network element can obtain all available SMF instances based on local configuration or from the NRF network element. If the second user logs in to the UE through User ID#1, the AMF network element can obtain the user information or user contract data corresponding to User ID#1 from the UDM network element based on User ID#1, and determine the DNN and S-NSSAI subscribed by User ID#1 based on the user information or user contract data, thereby selecting an SMF network element that can serve all DNN and S-NSSAI subscribed by User ID#1, or an SMF network element in an SMF set. Each SMF network element in the SMF set can share relevant information about the PDU session. If the second user logs in to the UE through the default mode, the AMF network element can obtain the contract data corresponding to the UE from the UDM network element, thereby selecting an SMF network element that can serve all DNN and S-NSSAI subscribed by the UE, or an SMF network element in an SMF set, based on the DNN and S-NSSAI subscribed by the UE.

[0264] The AMF network element records the identifier of the SMF network element selected for the UE (such as SMF ID) in the context of the UE.

[0265] S503. The AMF network element sends a session SM context establishment request message to the SMF network element, requesting to establish a session for the second user. The request message carries the SUPI, or carries the SUPI and User ID#1, or carries the SUPI and the first indication information. Exemplarily, the request message may be Nsmf_PDUSession_CreateSMContext Request.

[0266] For details of S503, please refer to the above introduction to S403, which will not be elaborated here.

[0267] S504. Based on the information included in the received request message, the SMF network element queries the UDM network element for the UE subscription data, or queries the UDM network element for the user information or user subscription data corresponding to User ID#1, and determines whether a PDU session can be established based on the obtained user information or user subscription data.

[0268] For details of S504, please refer to the above introduction to S404, which will not be elaborated here.

[0269] S505. If the SMF network element determines that the PDU session can be established, the SMF creates an SM context associated with the PDU session and sends a session SM context establishment request response message to the AMF network element. The response message includes the identifier of the SM context created by the SMF network element for the PDU session (for example, the ID of the SM context). In addition, the SMF network element records User ID#1 or the first indication information in the SM context of the UE. If the session cannot be established, the session SM context establishment request response message sent by the SMF to the AMF indicates that the establishment of the PDU session is rejected, and the process ends.

[0270] For details of S505, please refer to the above introduction to S405, which will not be elaborated here.

[0271] S506: Establish a PDU session for the second user. For details, please refer to the above introduction to S406.

[0272] Among them, different from S406 is that if the second user is authenticated twice, the SMF network element saves the correspondence between User ID#1 (or the first indication information), DNN, PDU session ID and authentication result.

[0273] S507 . The first user logs in to the UE using the first user's identifier: User ID#2.

[0274] The UE sends an SM message to the AMF network element. For example, the SM message may be a PDU session establishment request message. The message includes User ID #2 and the second indication information.

[0275] Based on the second indication information, the AMF network element determines to select the same SMF network element or the SMF network element in the same SMF set (SMF Set) when establishing a session for the UE.

[0276] Based on the above introduction to the registration of the terminal device to the network, it can be known that the AMF network element can determine the UE logged in by the first user through the NGAP identifier in the message header. Based on this, the AMF network element can determine that the SMF network element selected for the UE logged in by the first user needs to be the same SMF network element as the SMF network element selected when the second user logged in to the UE, or needs to be an SMF network element in the same SMF set.

[0277] Optionally, before the UE sends the SM message to the AMF network element, a deregistration process for the second user may occur. For details, please refer to the above description of S407, which will not be expanded here. Similarly, if a deregistration process for the second user occurs, the second user's session is released, and S512-515 are skipped.

[0278] S508. The AMF network element selects a suitable SMF network element.

[0279] The AMF network element selects the same SMF network element or a SMF network element in the same SMF set for the UE logged in by the first user at this time based on the identifier of the SMF network element selected for the UE logged in by the second user recorded in S502.

[0280] S509. The AMF network element sends a session SM context establishment request message to the SMF network element. The request message requests to establish a session for the first user. The request message carries SUPI and User ID#2.

[0281] S510. The SMF network element queries the user information or user contract data corresponding to User ID#2 based on the received request message, and determines whether a PDU session can be established based on the obtained user information or user contract data.

[0282] S511. If the SMF network element determines that the PDU session can be established, the SMF network element creates an SM context associated with the PDU session and sends a session SM context establishment request response message to the AMF network element. The response message includes the identifier of the SM context created by the SMF network element for the PDU session (for example, the ID of the SM context), and the SMF network element records User ID#2 in the UE's SM context. If the PDU session cannot be established, the SMF sends a session SM context establishment request response message to the AMF indicating that the PDU session is rejected, and the process ends.

[0283] For details of S509-S511, please refer to the above introduction to S503-S505, which will not be elaborated here.

[0284] S512, the SMF network element identifies that a PDU session is being established for a new user at this time. The embodiment of the present application does not limit how the SMF network element specifically identifies that a PDU session is being established for a new user. For example, the SMF network element can determine that a PDU session is being established for a new user by comparing the User ID#1 / first indication information carried in the session SM context establishment request message in S503 with the User ID#2 carried in the session SM context establishment request message in S509. For another example, if the SMF network element performs a secondary authentication on the second user and saves the correspondence between User ID#1 (or the first indication information), DNN, PDU session ID and the authentication result, the SMF network element can determine that a PDU session is being established for a new user by comparing User ID#1 / first indication information with User ID#2.

[0285] Furthermore, the SMF network element performs the following three steps:

[0286] The authentication result for the second user is deleted.

[0287] Authenticate the first user.

[0288] Determine to release all or part of the session established for the second user (ie release all or part of the second session), the second session determined to be released is hereinafter referred to as the first session. For specific implementation, please refer to the above introduction to S409 and will not be elaborated here.

[0289] The order of the above three steps is not fixed.

[0290] S513. The SMF network element triggers the release of the N4 session, and releases the IP address / IP prefix associated with the first session, as well as all resources and contexts associated with the N4 session by interacting with the UPF network element.

[0291] S514. The SMF network element sends an SM context release request response to the AMF network element. This response message is used to inform the AMF network element that the SM context of the first session has been released. After receiving the response message, the AMF network element releases the relevant information of the first session it has saved, such as the ID of the associated SMF network element.

[0292] S515: The SMF network element notifies the UDM network element that the first session has been released and instructs the UDM network element to remove the stored association between the SMF ID, DNN, and PDU session ID associated with the first session. After the UDM network element is removed, it can notify the SMF network element that the association has been removed. For details about S515, please refer to the above description of S514 and will not be elaborated here.

[0293] Assuming that the execution subject of S301-S303 is a terminal device, and the terminal device is a UE, in this scenario, the network side establishes a PDU session for the second user after the second user logs in to the UE, and releases one or more PDU sessions established for the second user after the first user logs in to the UE. A possible, non-limiting process is shown in Figure 6, including the following steps:

[0294] S601: A second user logs in to the UE using the default mode or the second user's identifier, User ID #1. After the second user logs in to the UE, the UE enables the core network to learn that the second user currently logged in to the UE has logged in using the default mode, or enables the core network to learn the identifier, User ID #1, of the second user currently logged in to the UE. The network establishes a PDU session (i.e., a second session) for the second user.

[0295] For details of S601, please refer to the above introduction to S401-S406, which will not be elaborated here.

[0296] S602: The first user logs in to the UE using the user ID: User ID#2. The UE recognizes that the user logging in to the UE has changed, and determines that the second session needs to be released.

[0297] FIG6 shows two possible implementations of releasing the second session: solution c and solution d.

[0298] Solution c: The UE triggers the release of all second sessions.

[0299] Specifically, the UE sends an SM message to the AMF network element, which contains the identifier of each existing session (i.e., each second session) on the UE, and is used to request the release of each second session. Exemplarily, the message can be a PDU session release request message. After receiving the session release request message, the AMF network element sends an SM context release request message to the SMF network element, which carries information indicating each second session, such as the ID of each second session or the ID of the SM context. Exemplarily, the message can be an Nsmf_PDUSession_ReleaseSMContext Request message.

[0300] Solution d: The network side triggers the release of the second session that cannot be multiplexed by the first user.

[0301] Specifically, the UE sends an SM message to the AMF network element, which requests the release of the session, and the message includes User ID#2. After receiving the message, the AMF network element searches for the user information or user contract data corresponding to User ID#2, and combines the relevant information of the second session to determine which second sessions can be reused by the first user and which cannot be reused by the first user. For how the AMF network element determines whether the second session can be reused by the first user, please refer to the above introduction to S302, which will not be elaborated here. The AMF network element sends the identifier of the PDU session that needs to be released to the SMF network element through an SM context update request message or an SM context release request message.

[0302] S603. The SMF network element triggers the release of the N4 session based on the received SM context release request message, and releases the IP address / IP prefix associated with the first session, as well as all resources and contexts associated with the N4 session by interacting with the UPF network element.

[0303] S604. The SMF network element sends an SM context release request response to the AMF network element. This response message is used to inform the AMF network element that the SM context of the first session has been released. After receiving the response message, the AMF network element releases the relevant information of the first session it has saved, such as the ID of the associated SMF network element.

[0304] S605. The SMF network element notifies the UDM network element that the first session has been released and instructs the UDM network element to remove the stored association between the SMF ID, DNN, and PDU session ID associated with the first session. After removing the association, the UDM network element may send a Nudm_UECM_Deregistration Response message to the SMF network element to notify the SMF network element that the UDM network element has removed the association.

[0305] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of interaction between various network elements. Accordingly, the embodiment of the present application also provides a communication device, which is used to implement the above various methods. The communication device can be the first network element in the above method embodiment, or a device including the above first network element, or a component that can be used for the first network element; or the communication device can be the terminal device in the above method embodiment, or a device including the above terminal device, or a component that can be used for the terminal device. Alternatively, the communication device can be other network elements in the above method embodiment, or a device including the above other network elements, or a component that can be used for other network elements.

[0306] It is understandable that, in order to realize the above functions, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0307] In the embodiment of the present application, the functional modules of the communication device can be divided according to the above method embodiment. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0308] FIG7 shows a schematic diagram of the structure of a communication device 700. The communication device 700 includes an acquisition module 701 and a processing module 702. The processing module 702, which may also be referred to as a processing unit 702, is configured to implement processing functions. Optionally, the communication device 700 may further include a transceiver module 703 and / or a storage module 704.

[0309] Taking communication device 700 as the first network element in the above method embodiment as an example, in one possible design, acquisition module 701 is configured to obtain the first user's identifier after the first user logs into the terminal device. Processing module 702 is configured to determine, based on the first user identifier, whether to release one or more first sessions, where the one or more first sessions belong to at least one second session established by a second user through the terminal device, and the second user logged into the terminal device before the first user. Processing module 702 is also configured to trigger the release of the one or more first sessions.

[0310] Taking the communication device 700 as an example of other network elements in the above method embodiment, the transceiver module is used to receive a second message from the first network element, the second message includes a first indication information, and the second message is used to request the establishment of a session management context for the session corresponding to the second user. In the case where the first indication information indicates that the second user logs in to the terminal device through the default mode, the acquisition module 701 is used to obtain the contract data corresponding to the terminal device; the processing module 702 is used to determine whether to establish a context for the session corresponding to the second user based on the contract data corresponding to the terminal device. In the case where the first indication information indicates that the second user logs in to the terminal device through the second user's identifier, the acquisition module 701 is used to obtain user information or contract data corresponding to the second user's identifier, and the processing module 702 is used to determine whether to establish a context for the session corresponding to the second user based on the user information or contract data corresponding to the second user's identifier.

[0311] Taking communication device 700 as another network element in the above method embodiment as an example, in another possible design, transceiver module 703 is configured to receive a seventh message from a terminal device, where the seventh message includes second indication information, where the second indication information is used to indicate that the terminal device can be logged in by different users at different times. Processing module 702 is configured to determine, based on the second indication information, whether to select the same first network element or a first network element in the same set when establishing sessions corresponding to different users for the terminal device.

[0312] Among them, all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here.

[0313] Optionally, in the communication device shown in FIG7 , the names of the modules may not be the names shown in the figure. For example, the transceiver module may also be called a communication module or a communication unit.

[0314] If the various units in Figure 7 are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (processor) to execute all or part of the steps of the method described in each embodiment of the present application. The storage medium for storing computer software products includes: various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0315] In the embodiment of the present application, the communication device 700 is presented in the form of various functional modules divided in an integrated manner. The "module" here can refer to an application-specific integrated circuit (ASIC), a circuit, a processor and memory that executes one or more software or firmware programs, an integrated logic circuit, and / or other devices that can provide the above functions.

[0316] In a simple embodiment, those skilled in the art may appreciate that the communication device 700 may take the form of the communication device 800 shown in FIG. 8 .

[0317] As shown in Figure 8, the communication device 800 includes one or more processors 801, a communication line 802, and at least one communication interface (Figure 8 is only an example of including a communication interface 804 and a processor 801 for illustration), and may optionally also include a memory 803.

[0318] The processor 801 may be a general-purpose central processing unit (CPU), a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of the program of the present application.

[0319] The communication line 802 may include a path for connecting different components.

[0320] The communication interface 804 may be a transceiver module for communicating with other devices or communication networks, such as Ethernet, RAN, terminals, and wireless local area networks (WLANs). For example, the transceiver module may be a device such as a transceiver or a transceiver. Alternatively, the communication interface 804 may be a transceiver circuit or input / output interface within the processor 801, for implementing signal input and output to the processor.

[0321] The memory 803 may be a device having a storage function. For example, it may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor via a communication line 802. The memory may also be integrated with the processor.

[0322] The memory 803 is used to store computer-executable instructions for executing the solution of the present application, and the execution is controlled by the processor 801. The processor 801 is used to execute the computer-executable instructions stored in the memory 803, thereby implementing the session management method provided in the embodiment of the present application.

[0323] Alternatively, optionally, in an embodiment of the present application, the processor 801 may also perform processing-related functions in the session management method provided in the above embodiment of the present application, and the communication interface 804 may be responsible for communicating with other devices or communication networks. The embodiment of the present application does not specifically limit this.

[0324] Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application code, which is not specifically limited in the embodiments of the present application.

[0325] In a specific implementation, as an embodiment, the processor 801 may include one or more CPUs, such as CPU0 and CPU1 in FIG8 .

[0326] In a specific implementation, as an embodiment, the communication device 800 may include multiple processors, such as the processor 801 and the processor 807 in FIG8 . Each of these processors may be a single-core processor or a multi-core processor. The processors herein may include, but are not limited to, at least one of the following: a CPU, a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor, and other types of computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform calculations or processing.

[0327] In a specific implementation, as an embodiment, the communication device 800 may further include an output device 805 and an input device 806. The output device 805 communicates with the processor 801 and can display information in a variety of ways. For example, the output device 805 can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 806 communicates with the processor 801 and can receive user input in a variety of ways. For example, the input device 806 can be a mouse, a keyboard, a touch screen device, or a sensor device.

[0328] The communication device 800 described above may sometimes also be referred to as a communication device, which may be a general-purpose device or a dedicated device. For example, the communication device 800 may be the first network element, terminal device, or other network element described above, or a device having a similar structure as shown in FIG8 . The embodiment of the present application does not limit the type of the communication device 800.

[0329] In addition, the composition structure shown in Figure 8 does not constitute a limitation on the communication device. In addition to the components shown in Figure 8, the communication device 800 may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0330] Alternatively, the functions / implementation processes of the acquisition module 701 and the processing module 702 in FIG7 may be implemented by the processor 801 in the communication device 800 shown in FIG8 calling computer-executable instructions stored in the memory 803. Alternatively, the functions / implementation processes of the processing module 702 in FIG7 may be implemented by the processor 801 in the communication device 800 shown in FIG8 calling computer-executable instructions stored in the memory 803, and the functions / implementation processes of the acquisition module 701 in FIG7 may be implemented by the communication interface 804 in the communication device 800 shown in FIG8.

[0331] It should be understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of the two. When any of the above modules or units is implemented in software, the software exists in the form of computer program instructions and is stored in a memory, and a processor can be used to execute the program instructions and implement the above method flow. The processor can be built into an SoC or ASIC, or it can be an independent semiconductor chip. In addition to the core used to execute software instructions to perform calculations or processing within the processor, it can further include necessary hardware accelerators, such as FPGAs, programmable logic devices (PLDs), or logic circuits that implement dedicated logic operations.

[0332] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, a microprocessor, a DSP chip, an MCU, an artificial intelligence processor, an ASIC, a SoC, an FPGA, a PLD, a dedicated digital circuit, a hardware accelerator or a non-integrated discrete device, which can run the necessary software or not rely on the software to execute the above method flow.

[0333] Optionally, an embodiment of the present application further provides a communication device (for example, the communication device may be a chip or a chip system), which includes a processor for implementing the method in any of the above method embodiments. In one possible design, the communication device also includes a memory. The memory is used to store necessary program instructions and data, and the processor can call the program code stored in the memory to instruct the communication device to execute the method in any of the above method embodiments. Of course, the memory may not be in the communication device. When the communication device is a chip system, it may be composed of a chip, or it may include a chip and other discrete devices, which is not specifically limited in the embodiment of the present application.

[0334] Optionally, an embodiment of the present application also provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is run on a communication device, the communication device can execute the method described in any of the above method embodiments or any of its implementation methods.

[0335] Optionally, an embodiment of the present application further provides a computer program product, which stores a computer program or instructions. When the computer program or instructions are run on a communication device, the communication device can execute the method described in any of the above method embodiments or any of its implementation methods.

[0336] Optionally, an embodiment of the present application further provides a communication system, which includes the first network element described in the above method embodiment and the other network elements described in the above method embodiment.

[0337] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using a software program, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more media integrated therein. The available media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media (eg, solid state drives (SSDs)).

[0338] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0339] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, the present application is intended to encompass such modifications and variations as fall within the scope of the claims of the present application and their equivalents.

Claims

1. A session management method, characterized in that: The method comprises: After the first user logs in to the terminal device, obtaining the identifier of the first user; Determine, based on the first user identifier, to release one or more first sessions, where the one or more first sessions belong to at least one second session established by a second user through the terminal, where the second user logged into the terminal device before the first user; A release of the one or more first sessions is triggered.

2. The method according to claim 1, characterized in that The determining, according to the identifier of the first user, to release one or more first sessions includes: When it is determined, based on the identifier of the first user, that a user logged into the terminal device has changed, it is determined to release the one or more first sessions.

3. The method according to claim 1, characterized in that The determining, according to the identifier of the first user, to release one or more first sessions includes: When a release request is received from the terminal device, it is determined to release the one or more first sessions; the release request includes an identifier of the first user.

4. The method according to any one of claims 1 to 3, characterized in that The determining, according to the identifier of the first user, to release one or more first sessions includes: Sending a first message to another network element, where the first message includes an identifier of the first user, and the first message is used to request user information or subscription data corresponding to the identifier of the first user; receiving user information or subscription data corresponding to the identifier of the first user from the other network element; The one or more first sessions are determined according to user information or subscription data corresponding to the identifier of the first user.

5. The method according to claim 4, characterized in that The determining, based on the user information or subscription data corresponding to the identifier of the first user, the one or more first sessions includes: determining, based on user information or subscription data corresponding to the identifier of the first user, parameters subscribed to by the identifier of the first user, the parameters being used to determine a session; According to the parameters subscribed by the identifier of the first user and the parameters corresponding to each second session in the at least one second session, a second session having corresponding parameters different from the parameters subscribed by the identifier of the first user is determined as the first session.

6. The method according to any one of claims 1 to 5, characterized in that Before the second user logs in to the terminal device, the method further includes: Receive first indication information, where the first indication information is used to instruct the second user to log in to the terminal device through a default mode or the second user to log in to the terminal device using a second user identifier.

7. The method according to claim 6, characterized in that After receiving the first indication information, the method further includes: The first indication information is recorded in the description information of the terminal device.

8. The method according to claim 6 or 7, characterized in that The method further comprises: Send a second message to another network element, where the second message includes the first indication information, and the second message is used to request establishment of a session management context for the session corresponding to the second user.

9. The method according to any one of claims 1 to 8, characterized in that The obtaining the identifier of the first user includes: receiving a third message from the terminal device, where the third message includes an identifier of the first user; The third message is used to request that the first user be registered with the network; or, the third message is used to request that the network authenticate the first user; or, the third message is used to request that a session be established for a user corresponding to the first user.

10. The method according to any one of claims 1 to 9, characterized in that The triggering the release of the one or more first sessions includes: A fourth message is sent, where the fourth message includes identification information for identifying the one or more second sessions, and the fourth message is used to request the release of the one or more second sessions.

11. The method according to any one of claims 1 to 6, characterized in that: The obtaining of the first user's identifier includes: A fifth message is received from another network element, where the fifth message includes an identifier of the first user, and the fifth message is used to request establishment of a context for a session corresponding to the first user.

12. The method according to claim 8, characterized in that The method further comprises: When the first indication information indicates that the second user logs in to the terminal device through a default mode, the other network element obtains subscription data corresponding to the terminal device, and determines whether to establish a context for a session corresponding to the second user according to the subscription data corresponding to the terminal device; When the first indication information indicates that the second user logs in to the terminal device through the second user's identifier, the other network element obtains the user information or contract data corresponding to the second user's identifier, and determines whether to establish a context for the session corresponding to the second user based on the user information or contract data corresponding to the second user's identifier.

13. The method according to claim 11, characterized in that Before receiving the fifth message from the other network element, the method further includes: The other network element receives a seventh message from the terminal device, where the seventh message includes second indication information, wherein the second indication information is used to indicate that the first terminal device can be logged in by different users at different times; When the other network elements determine, based on the second indication information, to establish sessions corresponding to different users for the terminal device, they select the same session management network element or session management network elements in the same set.

14. A communication device, characterized in that: The communication device includes a module or unit for implementing the method according to any one of claims 1 to 11; or, the communication device includes a module or unit for implementing the method according to claim 12 or 13.

15. The device according to claim 14, characterized in that The communication device is a chip or a chip system.

16. A communication device, characterized in that: The communication device includes: a processor and an interface circuit, the interface circuit is used to communicate with a device outside the communication device, and the processor is used to execute instructions stored in a memory; when the instructions are executed by the processor, the communication device executes the method according to any one of claims 1 to 11, or the communication device executes the method according to claim 12 or 13.

17. The device according to claim 16, characterized in that The communication device further includes the memory.

18. The device according to claim 16 or 17, characterized in that The communication device is a chip or a chip system.

19. A computer-readable storage medium, characterized in that Instructions are stored thereon, and when the instructions are executed by a computer, the method according to any one of claims 1 to 11 is executed; or the method according to claim 12 or 13 is executed.

20. A computer program product, characterized in that Instructions are stored thereon, and when the instructions are executed by a computer, the method according to any one of claims 1 to 11 is executed; or the method according to claim 12 or 13 is executed.

21. A communication system, characterized in that: The communication system includes a first network element and other network elements; the first network element is used to execute the method according to any one of claims 1 to 11; and the other network elements are used to execute the method according to claim 12 or 13.

Images