Session management method and apparatus

Abstract

Embodiments of this application provide a session management method and apparatus. The method includes: an access network element receiving a first message from a terminal device, the first message including a first session identifier and a first non-access layer NAS message, the first NAS message being used to request the establishment or activation of a first session corresponding to the identifier; and the access network element transmitting a second message to a first session management function network element, the second message including the first NAS message and the identifier of the terminal device. In this solution, the access network element may be directly connected to the first session management function network element (for example, directly connected to the first session management function network element based on a service-oriented interface), and the access network element directly exchanges NAS messages with the first session management function network element without being forwarded by an AMF. This can improve the flexibility of deploying core network elements and improve the efficiency of managing and controlling network session-related procedures.

Description

[Technical Field]

[0001] The present application relates to the field of communication technology, and in particular, to a communication method and apparatus. [Background Art]

[0002] (Cross-reference to Related Applications) The present application claims priority to Chinese Patent Application No. 202310852461.0 filed with the National Intellectual Property Administration of China on July 11, 2023, entitled "SESSION MANAGEMENT METHOD AND APPARATUS", which is incorporated herein by reference in its entirety.

[0003] Currently, in wireless communication systems, an Access and Mobility Management Function (Access and Mobility Management Function, AMF) network element is used as a relay for non-access stratum (non-access stratum, NAS) signaling, and interaction between a terminal device or an access network device and another core network element needs to rely on forwarding by the AMF. The deployment of core network elements is not flexible. Therefore, the flexibility for the network to manage and control protocol data unit (protocol data unit, PDU) session-related procedures is insufficient. [Summary of the Invention]

[0004] Embodiments of the present application provide a session management method and apparatus for implementing distributed connections between an access network device and a core network element, improving the flexibility for the network to manage and control session-related procedures.

[0005] According to a first embodiment, a session management method is provided. The method may be applied to an access network element or a chip within an access network element. An example in which the method is applied to an access network element is used. The method includes the access network element receiving a first message from a terminal device, the first message comprising a first session identifier and a first non-access layer NAS message, the first NAS message being used to request the establishment or activation of a first session corresponding to the identifier; and the access network element transmitting a second message to a first session management function network element, the second message comprising the first NAS message and the identifier of a terminal device.

[0006] In the aforementioned solution, the access network element can be directly connected to the first session management function network element (for example, directly connected to the first session management function network element based on a service-oriented interface), and the access network element directly exchanges NAS messages with the first session management function network element without being forwarded by the AMF. This can improve the flexibility of deploying core network elements and improve the efficiency of managing and controlling network session-related procedures.

[0007] In a possible design, before the access network element sends a second message to the first session management network element, the access network element may receive a third message from the registration network element, the third message containing at least one piece of information, the registration network element being the registration network element to which the terminal device is registered. Correspondingly, the access network element may send a second message to the first session management network element based on at least one piece of information.

[0008] In this way, the access network element can improve the reliability of the solution by forwarding a first NAS message to a first session management network element based on at least one piece of information provided by the registration function network element.

[0009] In a possible design, at least one piece of information includes a first piece of information indicating that the terminal device is located in an authorized area or not in an unauthorized area, or the first piece of information indicates both an authorized and / or unauthorized area. Correspondingly, if the terminal device is located in an authorized area or not in an unauthorized area, the access network element sends a second message to the first session management function network element.

[0010] In this way, the access network element forwards NAS messages sent by the terminal device to the corresponding session management function network element only if the terminal device is located in an authorized area or not in an unauthorized area, and avoids forwarding NAS messages from terminal devices in unauthorized areas to the session management function network element.

[0011] In a possible design, if at least one piece of information includes a second piece of information in which the second piece of information indicates an permitted message type and correspondingly includes a message type corresponding to the first NAS message, the access network element sends the second message to the first session management function network element; or if the second piece of information indicates an unauthorized message type and correspondingly does not include a message type corresponding to the first NAS message, the access network element sends the second message to the first session management function network element.

[0012] In this way, the access network element forwards only NAS messages of permitted message types to the session management network element, in order to avoid forwarding NAS messages of unauthorized message types to the session management network element.

[0013] In a possible design, at least one piece of information includes a third piece of information indicating whether the terminal device is permitted to perform access. Correspondingly, if the third piece of information indicates that the terminal device is permitted to perform access, the access network element sends a second message to the first session management network element.

[0014] In this way, the access network element forwards NAS messages sent by the terminal device to the corresponding session management function network element only if the terminal device is permitted to access the domain, and avoids forwarding NAS messages from terminal devices that are not permitted to perform access to the session management function network element.

[0015] In a possible design, the third message further includes an identifier for the registration function network element, and the second message further includes an identifier for the registration function network element.

[0016] In this way, the access network element provides the identifier of the registration network element to the first session management network element.

[0017] In a possible design, the first NAS message is used to request the establishment of a first session corresponding to an identifier, and the first NAS message is a session establishment request message, and the first NAS message contains the identifier of the first session. In other words, the method in this embodiment of the present application may be applied to a session establishment scenario.

[0018] In a possible design, in a session establishment scenario, after the access network element receives a first message from the terminal device, and before the access network element sends a second message to the first session management function network element, the access network element further sends a first request to the selection function network element. The first request is used to request the selection of the session management function network element for the first session. The access network element receives a first response from the selection function network element, which includes the identification information of the first session management function network element. Correspondingly, the access network element may send a second message to the first session management function network element based on the identification information of the first session management function network element.

[0019] In this way, the corresponding session management function network element (i.e., the first session management function network element) can be selected for the first session, thereby ensuring the reliability of session establishment.

[0020] In a possible design, in a session establishment scenario, before the access network element receives the first message from the terminal device, the access network element may further send an access request message to the registration network element, and the third message is a response message to the access request message.

[0021] In this way, the terminal device can access the network and perform the session establishment procedure. Furthermore, since the response message carries at least one piece of information, the number of interaction steps can be reduced, improving the efficiency of session establishment.

[0022] In a possible design, a first NAS message is used to request the activation of a first session corresponding to an identifier, and the first NAS message is either a service request message or a session activation request message, and the first NAS message contains the identifier of the first session. In other words, the method in this embodiment of the present application may be applied to a session activation scenario. It may be understood that a session needs to be activated in a service request scenario.

[0023] In a possible design, in a session activation scenario, an access network element may obtain the identification information of a first session management function network element, and the access network element may send a second message to the first session management function network element based on the identification information of the first session management function network element.

[0024] For example, an access network element may send a second request to a terminal context information repository function network element, which is used to query the session management function network element corresponding to the first session. The access network element receives a second response from the terminal context information repository function network element, which includes identification information for the first session management function network element.

[0025] In this way, the access network element may obtain identification information of the first session management function network element from the terminal context information repository function network element in order to improve the reliability of the solution.

[0026] For example, the first message includes identification information for a first session management function network element, and the access network element may obtain the identification information for the first session management function network element from the first message.

[0027] In this way, the terminal device can provide the identification information of the first session management function network element to the access network element, so that the access network element does not need to query the session management function network element from another location, thereby improving interaction efficiency.

[0028] Certainly, the aforementioned two methods for determining the first session management function network element are merely examples, and are not actually limited thereto.

[0029] In this way, the corresponding session management function network element (that is, the first session management function network element) can be determined for the first session, so as to ensure the reliability of session activation.

[0030] In a possible design, in a session activation scenario, before the access network element receives the third message from the registration function network element, the access network element may further send an access request message to the registration function network element, the access request message includes the identifier of the terminal device, and the third message is a response message to the access request message.

[0031] In this way, the terminal device can access the network and perform the session activation procedure. Furthermore, since the response message carries at least one piece of information, the number of interaction procedures can be reduced, and session establishment efficiency is improved.

[0032] In a possible design, after the access network element receives the first message from the terminal device, the access network element sends an access request message to the registration function network element.

[0033] In other words, since the terminal device can trigger both the access procedure and the session activation procedure simultaneously by sending a first message, the number of times the terminal device sends messages can be reduced, thereby reducing the terminal device's energy consumption.

[0034] In a possible design, before the access network element receives a first message from the terminal device, the access network element receives a fourth message from the terminal device, the fourth message containing a second NAS message, which is used to request access to the network or activation of a control plane connection. Correspondingly, the access network element sends an access request message to the registration network element based on the fourth message, the access request message containing a second NAS message.

[0035] In other words, the terminal device first sends a fourth message to connect to the network, and then, after accessing the network, sends a first message to activate the session. In this way, the terminal device no longer needs to perform access during the session activation procedure, thus improving the efficiency of the session activation procedure.

[0036] In a possible design, the first message includes an identifier for at least one session and at least one NAS message, the at least one NAS message having a one-to-one correspondence with at least one session, the NAS message corresponding to the first session in at least one session being used to request the establishment or activation of the first session, the first session being any one of the at least one sessions. Correspondingly, the access network element sends a second message to the session management function network element corresponding to each session.

[0037] In this way, multiple sessions can be established or activated synchronously, further improving the efficiency of session management and control.

[0038] According to a second embodiment, a session management method is provided. The method may be applied to a first session management function network element or a chip within the first session management function network element. An example is used in which the method is applied to the first session management function network element. The method includes the first session management function network element receiving a second message from an access network element, the second message comprising a first NAS message and an identifier for a terminal device, the first NAS message being used to request the establishment or activation of a first session, and the first session management function network element approving or rejecting the first NAS message based on mobility restriction information for the terminal device.

[0039] In a possible design, the first session management network element may obtain mobility restriction information for the terminal device from the registration network element based on the identifier of the registration network element, where the registration network element is the registration network element to which the terminal device is registered.

[0040] In a possible design, the second message further includes an identifier for the registration function network element.

[0041] In a possible design, the first session management function network element may alternatively obtain the terminal context information of the registration function network element from the terminal context information repository function network element based on the terminal context information of the terminal device. The terminal context information repository function network element stores the correspondence between the terminal context information of the registration function network element and the terminal context information of the terminal device.

[0042] In a possible design, the first session management function network element may alternatively obtain the terminal device's mobility restriction information from the terminal context information repository function network element, based on the terminal context information of the terminal device.

[0043] In a possible design, the mobility restriction information may include a fourth piece of information indicating whether the terminal device is located in an permitted or unauthorized area, and accordingly, if the terminal device is located in an permitted area or not in an unauthorized area, the first session management function network element approves the first NAS message; otherwise, the first session management function network element rejects the first NAS message.

[0044] In a possible design, mobility restriction information may include a fifth piece of information, which may indicate whether the terminal device is in an permitted or unpermitted area. Correspondingly, the first session management function network element may determine, based on the terminal device's location information and the fifth piece of information, whether the terminal device is located in an permitted area and / or an unpermitted area. If the terminal device is located in an permitted area or not in an unpermitted permitted area, the first session management function network element approves the first NAS message; otherwise, the first session management function network element rejects the first NAS message.

[0045] In a possible design, the second message further includes an identifier for the data network and / or a network slice, and the fifth information specifically indicates the permitted or unauthorized areas of the terminal device corresponding to the data network and / or network slice.

[0046] In a possible design, mobility restriction information includes a sixth piece of information, which indicates whether the wireless access technology is permitted or not. Correspondingly, if the wireless access technology of the access network element belongs to a permitted wireless access technology, or if the wireless access technology of the access network element does not belong to a prohibited wireless access technology, the first session management function network element approves the first NAS message; otherwise, the first session management function network element rejects the first NAS message.

[0047] According to a third aspect, a session management method is provided. The method may be applied to a registration function network element or a chip within a registration function network element. An example in which the method is applied to a registration function network element is used. The method includes the registration function network element receiving an access request message from an access network element, the access request message being used to request a terminal device to connect to the registration function network element (or network); and the registration function network element sending a third message to the access network element, the third message comprising at least one piece of information, the at least one piece of information being used by the access network element to determine whether to forward the first NAS message.

[0048] In a possible design, at least one piece of information will include, but will not be limited to, at least one of the following:

[0049] The first piece of information indicates that the terminal device is located in an authorized area or not in an unauthorized area, or the first piece of information indicates an authorized area and / or an unauthorized area. Second information, which indicates whether a message type is permitted or not, and A third piece of information, the third piece of information indicating whether the terminal device is permitted to perform the access.

[0050] In a possible design, the registration network element may further determine permitted or prohibited message types based on the terminal device's location information.

[0051] In a possible design, the registration function network element may alternatively transmit terminal device mobility restriction information to the first session management function network element.

[0052] Mobility restriction information includes at least one of the following:

[0053] A fourth piece of information, which indicates that the terminal device is located in an authorized or unauthorized area. A fifth piece of information, which indicates whether an area of ​​the terminal device is permitted or not, and The sixth piece of information, which indicates an authorized or unauthorized radio access technology.

[0054] In a possible design, the third message would alternatively include the identifier of the registration function network element. Alternatively, the registration function network element would send its identifier to the terminal context information repository function network element.

[0055] In a possible design, the third message is a response message to the access request message.

[0056] A fourth aspect provides a session management method. The method may be applied to a terminal device or a chip within a terminal device. An example of the method being applied to a terminal device is used. The method includes the terminal device generating a first message, and the terminal device transmitting the first message to an access network element, wherein the first message includes an identifier for at least one session and at least one NAS message, the at least one NAS message having a one-to-one correspondence with at least one session, and the NAS message corresponding to each of the at least one session being used to request the establishment or activation of a session.

[0057] In a possible design, the first message further includes identification information for at least one session management network element, the identification information for at least one session management network element having a one-to-one correspondence with at least one session, and each of the at least one session management network element is responsible for managing the session corresponding to the identification information of the session management network element.

[0058] In a possible design, the terminal device may further receive identification information of the session management network element from each of at least one session management network element.

[0059] In a possible design, before the terminal device sends the first message, it may send a fourth message to the access network element, the fourth message containing a second NAS message, which is used to request access to the network or activation of a control plane connection.

[0060] According to a fifth aspect, a communication device is provided. The device includes modules, units, or means configured to perform a method according to either the first aspect or a possible design thereof.

[0061] For example, the device is A transceiver unit may be configured to receive a first message from a terminal device, the first message including a first session identifier and a first non-access layer NAS message, the first NAS message being used to request the establishment or activation of a first session corresponding to the identifier, and to send a second message to a first session management function network element, the second message including the first NAS message and the terminal device identifier.

[0062] According to the sixth aspect, a communication device is provided. The device includes modules, units, or means configured to perform a method according to either the second aspect or a possible design of the second aspect.

[0063] For example, the device is A transceiver unit configured to receive a second message from an access network element, wherein the second message includes a first NAS message and an identifier for a terminal device, and the first NAS message is used to request the establishment or activation of a first session, and the transceiver unit... This may include a processing unit configured to approve or reject a first NAS message based on the mobility restriction information of a terminal device.

[0064] According to the seventh aspect, a communication device is provided. The device includes modules, units, or means configured to perform a method according to either the third aspect or a possible design of the third aspect.

[0065] For example, the device is A transceiver unit may be configured to receive an access request message from an access network element, which is used to request a terminal device to connect to a registration function network element (or network) on which the device is located, and to send a third message to the access network element, which includes at least one piece of information, at least one piece of information, which is used by the access network element to determine whether to forward the first NAS message.

[0066] According to the eighth aspect, a terminal device is provided. The terminal device includes a module, unit, or means configured to perform a method according to the fourth aspect or a possible design of the fourth aspect.

[0067] For example, terminal devices are A processing unit configured to generate a first message, A first message is sent to an access network element, the first message may include a transceiver unit and at least one session identifier and at least one NAS message, the at least one NAS message having a one-to-one correspondence with at least one session, and the NAS message corresponding to each of the at least one session being used to request the establishment or activation of the session.

[0068] According to the ninth aspect, a communication device is provided. The communication device includes a processor. The processor is coupled to memory, which is configured to store a program or instruction, and when a program or instruction is executed by the processor, the communication device is made to perform a method according to any one of the first aspect or a possible design of the first aspect, the second aspect or a possible design of the second aspect, the third aspect or a possible design of the third aspect, or the fourth aspect or a possible design of the fourth aspect.

[0069] According to the tenth aspect, a computer-readable storage medium is provided. The storage medium stores a computer program or instruction. When the computer program or instruction is executed by a communication device, a method according to one of the first aspect or a possible design of the first aspect, the second aspect or a possible design of the second aspect, the third aspect or a possible design of the third aspect, or the fourth aspect or a possible design of the fourth aspect is implemented.

[0070] According to the eleventh aspect, a chip is provided. The chip includes a processor, which is configured to execute program instructions in memory in order to perform a method according to any one of the following: the first aspect or a possible design of the first aspect, the second aspect or a possible design of the second aspect, the third aspect or a possible design of the third aspect, or the fourth aspect or a possible design of the fourth aspect.

[0071] According to the twelfth aspect, a computer program product including instructions is provided. The computer program product stores instructions. When instructions are executed on a computer, the computer is made to perform a method according to any one of the first aspect or a possible design of the first aspect, the second aspect or a possible design of the second aspect, the third aspect or a possible design of the third aspect, or the fourth aspect or a possible design of the fourth aspect.

[0072] According to the 13th aspect, a communication system is provided. The communication system includes a communication device according to the 5th aspect, a communication device according to the 6th aspect, a communication device according to the 7th aspect, and a communication device according to the 8th aspect.

[0073] For the technical effects that can be achieved in the second through thirteenth embodiments, please refer to the description of the technical effects that can be achieved in the corresponding design solutions of the first embodiment. Further details are again not described here in this application. [Brief explanation of the drawing]

[0074] [Figure 1]This is a diagram of the network architecture of a 5G communication system. [Figure 2] This is a diagram illustrating an example of the PDU session establishment procedure. [Figure 3] This is a diagram illustrating an example of a service request procedure. [Figure 4] This is a diagram of the network architecture of a communication system to which the embodiments of this application can be applied. [Figure 5] This is a flowchart of a session management method according to one embodiment of this application. [Figure 6] This is a flowchart of a network element selection method according to one embodiment of this application. [Figure 7] This is a flowchart of a session probability method according to one embodiment of this application. [Figure 8] This is a flowchart of a service request method according to one embodiment of this application. [Figure 9] This is a flowchart of a session management method according to one embodiment of this application. [Figure 10] This is a diagram showing the structure of a communication device according to one embodiment of this application. [Figure 11] This is a diagram showing the structure of another communication device according to one embodiment of this application. [Modes for carrying out the invention]

[0075] Figure 1 is a diagram of the network architecture of a 5th Generation (5G) communication system. The network functions and entities included in the system mainly include terminal devices (user equipment, UE), radio access network ((R)AN) elements, user plane function (UPF) network elements, data network (Data Network, DN), access and mobility management function (AMF) network elements, session management function (SMF) network elements, policy control function (PCF) network elements, application function (AF) network elements, network slice selection function (NSSF) network elements, authentication server function (AUSF) network elements, unified data management (UDM) network elements, network exposure function (NEF) network elements, network repository function (NRF) network elements, and unified data repository (UDR) network elements.

[0076] In this specification, for the sake of clarity, it should be understood that the names of each network function or entity may be represented by their English abbreviations. For example, the Session Management Function network element may be represented by SMF or the SMF network element.

[0077] Figure 1 illustrates the interaction relationships between network functions and entities and their corresponding interfaces. For example, a UE and an AMF can communicate with each other via an N1 interface, and a (R)AN and an AMF can communicate with each other via an N2 interface. The exchanged messages are referred to as N2 messages, and interfaces between network elements such as AMF, SMF, PCF, AF, NSSF, AUSF, UDM, and UDR are implemented using service-oriented interfaces.

[0078] UE, (R)AN, UPF, and DN are commonly referred to as data plane network functions and entities. Transmission can take place over user data traffic using a Protocol Data Unit Session (PDU) established between the UE and DN, and traffic can pass through two network function entities: (R)AN and UPF. The other parts are referred to as control plane network functions and entities, and are primarily responsible for functions such as authentication and authorization, registration management, session management, mobility management, and policy control, ensuring reliable and stable transmission of user layer traffic. The user plane is used to carry service data, and the control plane is used to carry signaling messages.

[0079] UE may also be referred to as terminal, user device, mobile station, mobile terminal, etc. Terminals can be widely used in a variety of scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, and smart cities. Terminal devices may include mobile phones, tablet computers, computers with wireless transceiver capabilities, wearable devices, vehicles, unmanned aerial vehicles, helicopters, airplanes, ships, robots, robotic arms, and smart home devices. In vehicle internet communication, a communication terminal mounted on a vehicle is a terminal device, and a roadside unit (RSU) may also be used as a terminal device. The specific technologies and device forms used by terminal devices are not limited to the embodiments of this application.

[0080] (R)AN may also be referred to as an access network device, access network node, (R)AN node, (R)AN entity, access node, (R)AN network element, etc., in order to assist terminal devices in performing wireless access.

[0081] Access network devices include, for example, base stations (BS), or radio resource management devices configured to control base stations. Base stations may include evolved node B (NodeB, eNB, or e-NodeB, evolved-NodeB) in long-term evolution (LTE) systems or long-term evolution-advanced (LTE-A) systems, or next-generation node B (gNB) or enhanced next-generation node B (en-gNB) in new radio (NR) systems of 5th generation (5G) mobile communication technology, or central units (CU) and distributed units (DU) in cloud radio access network (Could (R)AN) systems. This is not limited to the embodiments of this application.

[0082] In possible scenarios, multiple (R)AN nodes cooperate to help terminals perform radio access, while different (R)AN nodes independently perform several base station functions. For example, an (R)AN node could be a central unit (CU), a distributed unit (DU), a CU control plane (CP), a CU user plane (UP), or a radio unit (RU). CUs and DUs may be located separately or may be included in the same network element, e.g., a base band unit (BBU). An RU may be included in a radio frequency device or radio frequency unit, e.g., a remote radio unit (RRU), an active antenna unit (AAU), a processing unit, or a remote radio head (RRH).

[0083] In different systems, CU (or CU-CP and CU-UP), DU, or RU may also have different names, but those skilled in the art will understand their meaning. For example, in the O(R)AN 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 ease of explanation, CU, CU-CP, CU-UP, DU, and RU are used as illustrative examples in this application. Any one of CU (or CU-CP or CU-UP), DU, and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0084] The AMF is primarily responsible for signaling functions such as access control, mobility management, attachment and detachment, and gateway selection. When providing services to a session within a terminal device, the AMF provides control plane storage resources for the session to store the session identifier, the SMF identifier associated with the session identifier, and so on.

[0085] The SMF is responsible for selecting user plane network elements, redirecting user plane network elements, assigning Internet Protocol (IP) addresses, establishing, modifying, and releasing bearers, and controlling QoS.

[0086] The UPF is responsible for transferring and receiving user data within terminal devices. The UPF can receive user data from the data network and transmit it to terminal devices via access network devices, or it can receive user data from terminal devices via access network devices and transfer it to the data network. The transmission resources and scheduling functions used by the UPF to provide services to terminal devices are managed and controlled by the SMF.

[0087] NEF primarily supports secure communication between 3GPP networks and third-party applications.

[0088] Application Functions (AFs) primarily support and provide services by interacting with the 3GPP core network, for example, influencing data routing decisions or policy control functions, or providing several third-party services to the network side.

[0089] PCF is responsible for providing policy control decisions, policy rules for control plane functionality, and flow-based billing control functionality.

[0090] NSSF is primarily responsible for selecting network slices and determining which network slice instances the UE is allowed to access, based on UE slice selection assistance information, subscription information, and other factors.

[0091] The UDM is primarily responsible for managing UE subscription data, including storing and managing UE identifiers and UE access permissions.

[0092] AUSF supports authentication for both 3GPP and non-3GPP access.

[0093] NRF supports the registration and discovery of network functions.

[0094] The UDR stores and retrieves subscription data used by the UDM and PCF.

[0095] Indeed, the network elements in Figure 1 are merely examples, and in reality, it could include many more network elements.

[0096] Figure 1 shows that the access and mobility management function (AMF) is used as a relay for non-access stratum (NAS) signaling, and that communication between terminal devices or access network devices and other core network elements must rely on forwarding by the AMF.

[0097] The following examples use the PDU session establishment procedure and the service request procedure.

[0098] Figure 2 is a diagram illustrating an example of the PDU session establishment procedure. It includes the following steps:

[0099] S201.UE->AN->AMF:UE sends a NAS message to AMF, which may include single network slice selection information (S-NSSAI), data network name (DNN), PDU session identifier (PDU Session ID), request type, old PDU session identifier (Old PDU Session ID), and N1 session management (SM) container (the container contains a PDU session establishment request).

[0100] Specifically, to establish a new PDU session, the UE generates a new PDU session ID. The UE initiates the Request PDU Session Establishment procedure by forwarding an N1SM container, which is a NAS message containing the PDU session establishment request. The PDU session establishment request may include the Request PDU Type, the requested service and session continuity (SSC) mode, protocol configuration options, and the SM PDU DN Request Container.

[0101] S202.AMF selects an SMF and assigns it to manage PDU sessions.

[0102] SMF selection can be categorized into two types. AMF includes available SMF information (e.g., local configuration), and if no SMF information is available, the SMF selection function is used to select an SMF.

[0103] S203.AMF->SMF: AMF sends a PDU session creation context request (SMF Nsmf_PDUSession_CreateSMContext Request) message.

[0104] If the AMF and SMF do not have an association with a PDU session ID provided by the UE (for example, the request type indicates that the PDU session establishment request is an Initial Request), the AMF calls Nsmf_PDUSession_CreateSMContext Request. If the AMF and SMF do have an association with a PDU session ID provided by the UE (for example, the request type indicates an Existing PDU Session), the AMF calls Nsmf_PDUSession_UpdateSMContext Request.

[0105] S204.SMF<->UDM: The SMF subscribes to data from the UDM.

[0106] S205.SMF sends either a PDU session creation context response (Nsmf_PDUSession_CreateSMContext Response) or a PDU session update context response (Nsmf_PDUSession_UpdateSMContext Response) to AMF based on the request received in S203.

[0107] S206. The network performs secondary supplementary authentication / verification.

[0108] S206 may be an optional step, or S207a may be executed directly after S205 has been executed.

[0109] S207a.SMF selects PCF.

[0110] S207b.SMF<->PCF: Establish a session management policy.

[0111] S208.SMF selects UPF.

[0112] S209.SMF<->PCF: The SMF may perform a Session Management Policy Modification procedure to report certain events to a previously subscribed PCF.

[0113] S209 may be an optional step, or S210 may be executed directly after S208 has been executed.

[0114] S210.SMF<->UPF: N4 Session Establishment procedure. If the request type is an initial request, SMF initiates the N4 Session Establishment procedure; otherwise, SMF initiates the N4 Session Modification procedure.

[0115] S211.SMF->AMF:N1N2 message transmission (Namf_Communication_N1N2MessageTransfer).

[0116] The message may include the PDU session ID, access type, N2 SM information (PDU session ID, QFI, QoS profile, CN tunnel information, S-NSSAI, session-AMBR, and PDU session type), and the N1 SM container (PDU session establishment authorization (QoS rules, selected SSC mode, S-NSSAI, assigned IPv4 address, interface identifier, session-AMBR, and selected PDU session type)).

[0117] N2 SM information carries information forwarded to (R)AN by AMF. CN tunnel information corresponds to the core network address, QoS profile, and corresponding QFI of the N3 tunnel of the PDU session. The PDU session ID indicates to the UE the association between the AN resources and the PDU session for the UE, and the association between the PDU session and S-NSSAI and DNN.

[0118] The N1SM container contains information provided to the UE by the AMF, including PDU Session Establishment Acceptance.

[0119] S212.AMF->(R)AN:N2 PDU Session Request.

[0120] The request may include N2 SM information and NAS messages (PDU session ID and N1 SM container (PDU session establishment authorization)).

[0121] The AMF sends a NAS message to (R)AN containing the PDU session ID and PDU session establishment confirmation for the UE, as well as N2 SM information received from the SMF in the N2 PDU session request. The N2 SM information includes CN tunnel information.

[0122] S213.(R)AN->UE:(R)AN initiates an AN-specific signaling exchange with UE, and the exchange relates to information received from the SMF.

[0123] S214.(R)AN->AMF:N2 PDU Session Response.

[0124] The response may include the PDU session ID, cause, and N2 SM information (PDU session ID, AN tunnel information, and a list of accepted / rejected QFIs). The AN tunnel information corresponds to the access network address of the N3 tunnel for the PDU session.

[0125] S215.AMF->SMF:Nsmf_PDUSession_UpdateSMContext request.

[0126] The request may include N2 SM information and request type. The AMF forwards the N2 SM information received from (R)AN to the SMF.

[0127] S216.SMF<->UPF:N4 session correction procedure.

[0128] The SMF sends an N4 Session Modification Request to the UPF, and the SMF provides the UPF with AN tunnel information and corresponding forwarding rules. The UPF sends an N4 Session Modification Response to the SMF.

[0129] S217.SMF->AMF:Nsmf_PDUSession_UpdateSMContext response (Cause).

[0130] Subsequently, SMF can subscribe to UE mobility event notifications from AMF by calling the Event Exposure Subscription (Namf_EventExposure_Subscribe) service action. In the case of a local area data network (LADN), SMF subscribes to event notifications of UE movement to or from the LADN service domain. AMF forwards the relevant events subscribed to by SMF.

[0131] From steps S201 to S203, S205, S211 and S212, as well as S214 and S215, and other steps, it can be seen that the interaction between (R)AN and SMF depends on forwarding by AMF.

[0132] Figure 3 is a diagram illustrating an example of a service request procedure. It includes the following steps:

[0133] S301.UE->AN: Access Network Message (AN Message).

[0134] Messages may include access network parameters (AN parameters) and service requests. Service requests may include the following:

[0135] List of activated PDU sessions, list of allowed PDU sessions, security parameters, PDU session status, and 5G system architecture evolution temporary mobile identity (TMSI, S-TMSI).

[0136] If a service request is triggered by user data transmission, the UE must reactivate the PDU sessions and provide a list of the PDU sessions to be activated. If the service request is triggered solely by signaling, it is not necessary to provide PDU sessions. The PDU session status identifies all available PDU sessions in the UE. If the UE is not in an LADN area, the UE may not trigger the PDU session request procedure corresponding to the LADN. For a UE in a connected (CM-CONNECTED) state, the service request includes only the list of PDU sessions to be activated and the list of authorized PDU sessions. In the NG-(R)AN scenario, the AN parameters include the 5G-S-TMSI, the selected PLMN ID, and the establishment cause.

[0137] 5G-S-TMSI is an abbreviation for 5G-Globally Unique Temporary Identity (GUTI). 5G-S-TMSI is being introduced to reduce the size of air interface signaling message overhead and improve air interface efficiency.

[0138] 5G-GUTI: The purpose of using 5G-GUTI in 5G systems is to improve security by reducing the display of the permanent identifier of the UE during communication.

[0139] 5G-GUTI consists of two parts: (1) the first part, GUAMI, indicates the AMF to which 5G-GUTI is assigned, and (2) the second part, 5G-TMSI, indicates a unique identifier for the UE within the AMF.

[0140] S302.AN->AMF: An N2 message containing N2 parameters and a Service Request.

[0141] In the NG-(R)AN scenario, the N2 parameters include the 5G-S-TMSI, the selected PLMN ID, location information and establishment cause, and the UE Context Request.

[0142] If the UE is in the CM-IDLE state, the (R)AN obtains the 5G-GUTI in the RRC procedure. The (R)AN selects the AMF based on the 5G-GUTI. The location information is related to the cell where the UE is camped. Based on the PDU session status, the AMF initiates the PDU Session Release procedure in the network to release any PDU sessions indicated as available by the UE.

[0143] S303. If the service request is not sent with integrity protection, or if the integrity protection check fails, the AMF initiates the NAS authentication / security procedure. If a UE in CM-IDLE state triggers a service request solely to establish a signaling connection, steps S304 through S310, S313, etc. are skipped after the signaling connection between the network and the UE has been successfully established.

[0144] S304.AMF->SMF:Nsmf_PDUSession_UpdateSMContext request.

[0145] The request may include PDU session ID, Operation Type, UE location information, Access Type, RAT Type, UE presence in an LADN service area, and indication of the Access Type can be changed.

[0146] The AMF determines which PDU sessions to reactivate and sends an Nsmf_PDUSession_UpdateSMContext request to the SMF associated with those PDU sessions, indicating the cause as "User Plane Resource Creation". The Nsmf_PDUSession_UpdateSMContext request is invoked when the UE identifies a list of PDU sessions to be activated in the service request information. This procedure is triggered by the SMF, but the PDU sessions identified by the UE are different from the PDU sessions that trigger the procedure. The AMF determines which PDU sessions to activate. This procedure is triggered by the SMF, but the current UE location is outside the valid area provided by the SMF in the N2 information. The AMF determines which PDU sessions to activate.

[0147] The AMF may receive service requests to establish a new NAS signaling connection and trigger the release of the old NAS signaling connection. For PDU sessions identified as needing reactivation, the AMF requests the SMF to immediately activate the PDU session. For PDU sessions identified in the activated N3 user plane, if the PDU session is not on the list of PDU sessions to be reactivated, the AMF requests the SMF to deactivate the PDU session.

[0148] S305.SMF establishes a policy association with PCF and selects UPF.

[0149] S306 through S310.SMF configure the selected UPF.

[0150] S311.SMF->AMF:Nsmf_PDUSession_UpdateSMContext response.

[0151] The response includes N2 SM information, N1 SM container, and cause. N2 SM information includes PDU session ID, QFI, QoS profile, CN N3 tunnel information, S-NSSAI, User Plane Security Enforcement, UE Integrity Protection Maximum Data Rate, redundancy sequence number (RSN), and PDU Session Pair ID.

[0152] S312.AMF->(R)AN:N2 Request The request includes N2 SM information received from the SMF, security context, Mobility Restriction List, Aggregate Maximum Bit Rate (AMBR), List of UE-Slice-MBR, MMNAS Service Accept, list of recommended cells / TAs / NG-(R)AN node identifiers, UE Radio Capability, Core Network Assistance Information, Tracing Requirements, and UE Radio Capability ID.

[0153] S313.(R)AN->UE:NG-(R)AN performs RRC connection reconfiguration.

[0154] In steps S302 to S304, S311 and S312, and other steps, the interaction between (R)AN and SMF relies on forwarding by AMF. To address the problem of limited flexibility in managing and controlling PDU session-related procedures due to the inflexible deployment of the aforementioned core network elements, a technical solution in the embodiments of this application is provided, which enables distributed connectivity between access network devices and core network elements to improve the flexibility of network management and control of PDU session-related procedures.

[0155] Embodiments of this application may be applied to wireless mobile cellular networks, including 6th generation (6G) mobile communication systems and their advanced versions.

[0156] Figure 4 is a diagram of the network architecture of a communication system to which embodiments of this application can be applied. The network architecture may include some or all of several devices or network elements, such as terminal devices, access network devices, registration function network elements, SMF network elements (abbreviated as SMF), UPF network elements (abbreviated as UPF), PCF network elements (abbreviated as PCF), short message service function (SMSF) network elements (abbreviated as SMSF), UDM network elements (abbreviated as UDM), selection function network elements, and terminal context information repository function network elements.

[0157] To enable distributed connectivity and flexible deployment of core network elements, interfaces exist between access network devices and registration function network elements, SMF, UPF, PCF, SMSF, selection function network elements, and terminal context information repository function network elements. For example, if the network architecture is a service-oriented (R)AN-implemented network architecture, all interfaces between access network devices and registration function network elements, SMF, UPF, PCF, SMSF, selection function network elements, and terminal context information repository function network elements can be service-oriented interfaces.

[0158] The registration function network element is configured to provide access management or registration management functions to the user (or terminal device). The registration function network element may also be referred to as the access management function network element. In possible implementations, the registration function network element is an AMF (Application Management Facility).

[0159] A selection function network element is configured to select a core network element for a terminal device. Core network elements in the network can be registered with the selection function network element, and as a result, the selection function network element can select a target core network element for the terminal device from the registered core network elements. The selection function network element can obtain subscription data for the terminal device from the UDM network element and select a target core network element for the terminal device based on the core network element registration information and subscription data. The selection function network element may also be referred to as a network element selection function network element. In possible implementations, the selection function network element is an NRF.

[0160] The Terminal Context Information Repository (UTC) network element is configured to store context information (UE context information) for terminal devices, including context information generated when another core network element manages terminal devices. For example, the Terminal Context Information Repository network element is configured to store the correspondence between temporary and permanent identifiers of terminal devices. After generating or retrieving the correspondence between temporary and permanent identifiers of terminal devices, the registration network element may store the correspondence between temporary and permanent identifiers of terminal devices within the Terminal Context Information Repository network element. The Terminal Context Information Repository network element may also be referred to as the Identifier Repository network element. In another example, the Terminal Context Information Repository network element is configured to store session identification information and identification information of the session management network element responsible for session management. In possible implementations, the Terminal Context Information Repository network element is a UDR or unstructured data storage function (UDSF).

[0161] For other network elements in Figure 4, please refer to the explanation above. Further details will not be explained again here.

[0162] Figure 5 is a flowchart of a session management method according to one embodiment of the present application. For example, the method is applied to the network architecture shown in Figure 4. The method includes steps S501 to S503.

[0163] S501. The terminal device sends a first message, and (R)AN receives the first message, which includes the identifier of the first session and the first NAS message.

[0164] The first message may be an access network (AN) message.

[0165] The first NAS message relates to a first session. For example, the first NAS message is used to request the establishment of a first session. In other words, this embodiment of the present application may be applied to a session establishment scenario. Alternatively, the first NAS message is used to request the activation of a first session. In other words, this embodiment of the present application may be applied to a session activation scenario (for example, a service request scenario in which a session needs to be activated).

[0166] The first session may be a PDU session, a computing session, an artificial intelligence (AI) session, etc., and is not limited to this application. A computing session is a session related to computing tasks, and an AI session is a session related to AI tasks. For ease of explanation, a PDU session will be used primarily as an example herein.

[0167] It can be understood that (R)AN may not parse (or perceive) the content of a NAS message. Therefore, since the first message contains the identifier of the first session, (R)AN can determine that the first NAS message is related to the first session, and further, can decide to forward the first NAS message to the SMF (or the SMF corresponding to the first session) that manages the first session. For ease of explanation, the SMF that manages the first session will be referred to as the first SMF below.

[0168] In some embodiments, the RAN may forward the first NAS message directly to the first SMF (e.g., by performing step S502). In some other embodiments, (R)AN may first determine whether it is possible (or can or should be) to forward the first NAS message to the SMF, and if (R)AN determines that it is possible (or can or should be) to forward the first NAS message to the SMF, it may forward the first NAS message to the first SMF (e.g., by performing step S502).

[0169] In possible implementations, (R)AN can (or should be able to) forward the first NAS message to the first SMF if one or more of the following conditions are met:

[0170] (1) The terminal device is located in an allowed area and / or not in a non-allowed area.

[0171] In possible examples, permitted and / or dispermitted areas are Service Area Restrictions within Mobility Restriction information. When a terminal device is in a permitted area, it is permitted to initiate PDU session-related services. When a terminal device is in a dispermitted area, it is not permitted to initiate PDU session-related services. Therefore, a terminal device is permitted to initiate PDU session-related services only if it is located in a permitted area and / or not in a dispermitted area. Thus, (R)AN can forward the first NAS message to the first SMF to perform the first session-related procedure (e.g., the first session establishment procedure or activation procedure).

[0172] In certain implementations, (R)AN may determine, based on first information, whether the terminal device is located in an allowed area or a non-allowed area. The first information may directly indicate whether the terminal device is located in an allowed area or a non-allowed area. For example, the first information may indicate whether the terminal device is located in an allowed area or not, or the first information may indicate an allowed area and / or a non-allowed area. Based on the terminal device's location information and the first information, (R)AN determines whether the terminal device is located in an allowed area or a non-allowed area.

[0173] In another possible example, DNN / S-NSSAI is distinguished by service area restrictions. When a terminal device is in an authorized area corresponding to DNN / S-NSSAI, the terminal device is permitted to initiate a DNN / S-NSSAI-compatible session. When a terminal device is in an unauthorized area corresponding to DNN / S-NSSAI, the terminal device is not permitted to initiate a DNN / S-NSSAI-compatible session. The first message contains session attribute information such as DNN / S-NSSAI. Therefore, the terminal device is permitted to initiate a DNN / S-NSSAI-compatible session only if the terminal device is located in an authorized area corresponding to DNN / S-NSSAI and / or not in an unauthorized area. Thus, (R)AN can forward the first NAS message to the first SMF to perform the first session-related procedure (e.g., the first session establishment procedure or activation procedure).

[0174] In certain implementations, (R)AN may determine, based on the first information, whether the terminal device is located in an allowed area or a non-allowed area corresponding to DNN / S-NSSAI. The first information may directly indicate whether the terminal device is located in an allowed area or a non-allowed area corresponding to DNN / S-NSSAI. For example, the first information may indicate whether the terminal device is located in an allowed area or a non-allowed area corresponding to DNN / S-NSSAI. Alternatively, the first information may indicate the allowed and / or non-allowed areas corresponding to DNN / S-NSSAI. Based on the terminal device's location information and the first information, (R)AN determines whether the terminal device is located in an allowed area or a non-allowed area corresponding to NN / S-NSSAI.

[0175] (2) An authorized message type includes the message type corresponding to the first NAS message (or the message type corresponding to the first NAS message is an authorized message type), or an unauthorized message type does not include the message type corresponding to the first NAS message (or the message type corresponding to the first NAS message is not an unauthorized message type). In other words, (R)AN may forward NAS messages of authorized message types and will not forward NAS messages of unauthorized message types.

[0176] A permitted message type may specifically be a permitted NAS message type. An unpermitted message type is specifically an unpermitted NAS message type. This is not limited to the present application.

[0177] For example, the message types of NAS messages include, but are not limited to, session management non-access layer (SM NAS messages) messages and policy non-access layer (policy NAS messages). Allowed and / or unallowed message types may be set based on requirements. For example, SM NAS messages may be an allowed message type and policy NAS messages may be an unallowed message type, or SM NAS messages may be an unallowed message type and policy NAS messages may be an allowed message type. This is not particularly limited in this embodiment of the present application.

[0178] In certain implementations, (R)AN may determine, based on second information, whether the message type corresponding to the first NAS message is an authorized or unauthorized message type. The second information may directly indicate whether the message type corresponding to the first NAS message is an authorized or unauthorized message type. For example, the second information may indicate whether the message type corresponding to the first NAS message is an authorized or unauthorized message type. Alternatively, the second information may indicate authorized and / or unauthorized message types. Based on authorized and / or unauthorized message types, (R)AN determines whether the message type corresponding to the first NAS message is an authorized or unauthorized message type.

[0179] Optionally, the first message includes the message type of the first NAS message.

[0180] In some embodiments, permitted and / or unpermitted message types may be associated with permitted and / or unpermitted areas. (R)AN or AMF may determine permitted or unpermitted message types based on the location of the terminal device. For example, if (R)AN or AMF determines, based on the location of the terminal device and the permitted and / or unpermitted areas, that the terminal device is in an unpermitted area, then (R)AN or AMF determines that the SM NAS message is of a permitted message type and the policy NAS message is of an unpermitted message type. In other words, (R)AN may forward the SM NAS message to the SMF, but (R)AN may not forward the policy NAS message to the SMF. Certainly, this is just an example and is not limited to this in practice.

[0181] (3) The terminal device is authorized to perform access.

[0182] Being permitted to perform access may mean that the terminal device is permitted to access the network, or access the AMF, or access another network element. Being permitted to perform access may be equivalent to being permitted to establish session services.

[0183] In an implementation, (R)AN may determine whether a terminal device is permitted to perform access based on third information. The third information may directly indicate whether the terminal device is permitted to perform access. For example, the third information may indicate that the terminal device is permitted to perform access. Alternatively, the third information may be reference information used to determine whether the terminal device is permitted to perform access. For example, the third information may include radio access technology (RAT) restriction information, which indicates the radio access technology that the terminal device is permitted to use when accessing the network, e.g., 3GPP access. (R)AN may determine whether a terminal device is permitted to perform access based on the third information and the radio access technology used by the terminal device (e.g., the terminal device performs access via (R)AN and the radio access technology corresponding to (R)AN is 3GPP access). Indeed, the RAT restriction information here is merely an example. In practice, the third information may further include other content, such as permitted and / or unauthorized areas (when located in an permitted area, or when not located in an unauthorized area, the terminal device is permitted to perform the access). This is not limited to this embodiment of the present application.

[0184] In an alternative implementation, permission for a terminal device to perform access may be replaced with permission for a terminal device to establish a session service. (R)AN may determine whether a terminal device is permitted to establish a session service based on third information. The third information may directly indicate whether a terminal device is permitted to establish a session service. For example, the third information may indicate that a terminal device is permitted to establish a session service. Alternatively, the third information may be reference information used to determine whether a terminal device is permitted to establish a session service. For example, the third information may include S-NSSAI restriction information. S-NSSAI restriction information indicates information about slices that a terminal device is permitted to access, or information about slices that a terminal device is not permitted to access. (R)AN may determine whether a terminal device is permitted to establish a session service based on the third information and the S-NSSAI carried in the first message. For example, if the S-NSSAI carried in the first message belongs to information about slices that are permitted to access, or does not belong to information about slices that are not permitted to access, (R)AN determines that a terminal device is permitted to establish a session service.

[0185] It can be understood that after receiving the first message, (R)AN may determine whether it is possible (or possible, or necessary) to forward the first NAS message to the SMF, or (for example, in the registration procedure) before receiving the first message, whether it is possible (or possible, or necessary) to forward the NAS message to the SMF, or whether it is possible to forward the NAS message to the SMF, or whether it is possible to forward the NAS message to the SMF, and after receiving the first message, (R)AN may forward the first NAS message directly to the first SMF (for example, by performing step S502), or, based on the previously obtained determination, may not forward the first NAS message to the first SMF.

[0186] In a possible implementation, (R)AN may obtain or receive at least one of the first, second, and / or third pieces of information from the registration function network element. For ease of explanation, an example in which the registration function network element is AMF is used below.

[0187] Before (R)AN sends a second message to the first SMF, (R)AN may send an access request message to the AMF where the terminal device is registered. The access request message is used to request that the terminal device be connected to the AMF (or to the network), and may include an identifier for the terminal device (which may be a permanent or temporary identifier for the terminal device). After receiving the access request message, the AMF returns a third message to (R)AN. The third message is either a response message to the access request message or an initial context setup request message. The third message includes at least one of the first, second, or third pieces of information. The AMF is the AMF where the terminal device is registered, or the AMF responsible for managing access to the terminal device. It can be understood that the access request message here may be an initial access request message, i.e., the first access request message initiated by a terminal device, such as a registration request message or an initial terminal message (INITIAL UE MESSAGE), or it may not be an initial access request message (e.g., an access request message initiated by an idle terminal device). This is not limited to the present application.

[0188] Example 1: A session establishment scenario is used as an example. The first NAS message is used to request the establishment of the first session. For example, the first NAS message is a session establishment request message (e.g., a PDU session establishment request message). The first NAS message contains the identifier of the first session.

[0189] In the registration procedure for a terminal device (which occurs before (R)AN receives a first message from the terminal device), (R)AN may receive at least one of the first, second, or third pieces of information from the registration function network element. Specifically, the terminal device sends an AN message to (R)AN, which includes an access request message (which may also be referred to as a registration request message). (R)AN sends the access request message to the AMF, which receives the access request message. The AMF sends a response message to the access request message (i.e., a third message, e.g., a registration approval message) to (R)AN. (R)AN receives the response message, which includes at least one of the first, second, and / or third pieces of information.

[0190] Example 2: A session activation scenario is used as an example. The first NAS message is used to request the activation of the first session. The first NAS message may be a service request message (e.g., a Service Request Message) or a session activation request message (e.g., a PDU Session Activation Message). The first NAS message includes an identifier for the first session.

[0191] In a session activation scenario, the terminal device may initiate the service request procedure directly, or it may initiate the access procedure first and then the service request procedure.

[0192] When a terminal device directly initiates a service request procedure, after (R)AN receives a first message from the terminal device, (R)AN first sends an access request message (which may also be called an access notification message, etc.) to the AMF, and (R)AN receives a third message from the AMF, which is a response message to the access request message. After the terminal device decides to access the AMF (or network), (R)AN continues with the activation procedure for the first session.

[0193] When a terminal device first initiates an access procedure and then a service request procedure, before sending the first message, the terminal device first sends a fourth message to (R)AN, which includes a second NAS message, the second NAS message used to request access to the network or activation of the control plane connection. After receiving the fourth message, (R)AN sends an access request message (which may also be called an access notification message) to the AMF based on the fourth message, which includes a second NAS message. After receiving the fourth message, the AMF returns a third message to (R)AN. (R)AN receives the third message, which is a response message to the access request message, and (R)AN forwards the response message to the terminal device. After the terminal device accesses the network or the control plane connection is activated, the terminal device sends the first message to (R)AN.

[0194] The AMF on which the terminal device is registered may transmit the AMF identifier (e.g., AMF ID) to (R)AN. For example, the AMF identifier is carried in a third message. In this way, (R)AN can then provide the AMF identifier to the first SMF. Alternatively, the AMF on which the terminal device is registered may transmit the AMF identifier to a terminal context information repository function network element (e.g., UDR) so that the first SMF can then obtain the AMF identifier from the terminal context information repository function network element.

[0195] In this embodiment of the present application, before (R)AN forwards the first NAS message to the SMF corresponding to the first session (i.e., the first SMF), (R)AN must first determine the SMF corresponding to the first session, e.g., the first SMF.

[0196] Below are some possible implementations.

[0197] Method 1: (R)AN may obtain the identification information of the SMF corresponding to the first session from the selected functional network element.

[0198] A session establishment scenario is used as an example. See Figure 6. After receiving the first message from the terminal device, and before sending the second message to the first SMF, (R)AN may further perform steps S601 to S604.

[0199] S601.(R)AN is used to send a first request to a selectable network element (e.g., NRF), which is used to request the selection of an SMF for a first session (or terminal device).

[0200] The first request may include an identifier for the terminal device and network element type information, where the network element type information indicates the type of target core network element to be selected, e.g., SMF. Optionally, the first request may further include a network element selection container. The network element selection container includes session attribute information such as DNN and S-NSSAI. Correspondingly, the first message may further include a network element selection container. Optionally, the first request may further include session attribute information such as DNN and S-NSSAI. Correspondingly, the first message may further include session attribute information such as DNN and S-NSSAI.

[0201] The identifier of a terminal device may be a permanent identifier or a temporary identifier. This is not limited to this embodiment of the present application. A temporary identifier may include an identifier assigned to the terminal device by (R)AN or an identifier assigned to the terminal device by a registration function network element (e.g., AMF). If the temporary identifier includes an identifier assigned to the terminal device by a registration function network element, the registration function network element may transmit the identifier assigned to the terminal device to (R)AN, so that (R)AN may know the temporary identifier of the terminal device.

[0202] S602. This step is an optional process that can be performed, and the selection function network element may obtain the subscription data of the terminal device based on the terminal device identifier.

[0203] Terminal device subscription data may include network element selection subscription data, access and mobility management subscription data, slice selection subscription data, etc. If the terminal device identifier is a temporary identifier, the selection function network element must first obtain a permanent identifier corresponding to the temporary identifier, and then obtain the terminal device subscription data from the UDM based on the permanent identifier.

[0204] S603. The selection function network element selects the first SMF as the target SMF.

[0205] The selection function network element decides to select an SMF network element based on the network element type information in the first request. Specifically, the network element type information is the SMF network element type.

[0206] For example, the selection function network element selects a first SMF as the target SMF based on the subscription data of the terminal device.

[0207] In another example, a selection function network element selects a first SMF as the target SMF based on the network element selection container. Specifically, the selection function network element selects a first SMF responsible for managing session attributes such as DNN and S-NSSAI based on session attribute information such as DNN and S-NSSAI contained in the network element selection container.

[0208] In another example, the selection function network element selects a first SMF responsible for managing session attributes such as DNN and S-NSSAI, based on session attribute information such as DNN and S-NSSAI included in the first request.

[0209] S604. The selection function network element sends a first response to (R)AN, the first response containing the identification information of the first SMF. Correspondingly, (R)AN receives the identification information of the first SMF. For example, the identification information of the first SMF may be the address information of the first SMF.

[0210] Method 2: (R)AN may obtain the identification information of the SMF corresponding to the first session from a terminal context information repository function network element (e.g., UDR).

[0211] A session activation scenario is used as an example. After the first session is created, the first SMF or (R)AN may send the identification information of the first SMF and the identifier of the first session to a network repository function network element, which in turn stores the identification information of the first SMF and the identifier of the first session. Subsequently, when a terminal device activates the first session, (R)AN may retrieve or query the SMF corresponding to the first session from the terminal context information repository function network element based on the identifier of the first session. For example, (R)AN sends a second request to the terminal context information repository function network element, which is used to query the SMF corresponding to the first session, and the second request includes the identifier of the first session. The terminal context information repository function network element determines the identification information of the first SMF based on the identifier of the first session and sends a second response to (R)AN, which includes the identification information of the first SMF. (R)AN receives a second response from the terminal context information repository function network element.

[0212] Method 3: The terminal device transmits the identification information of the first SMF to (R)AN, and (R)AN receives the identification information of the first SMF transmitted by the terminal device.

[0213] A session activation scenario is used as an example. When the first session is created, the first SMF or (R)AN may send the first SMF's identification information to a terminal device, which the terminal device stores. Subsequently, when activating the first session, the terminal device may send the first SMF's identification information. For example, the first SMF's identification information is carried in the first message.

[0214] Indeed, the aforementioned methods by which (R)AN obtains the identification information of the first SMF are merely examples and are not actually limited to them.

[0215] In a session activation scenario, it can be understood that a terminal device may request the activation of one session at a time, or it may request the activation of multiple sessions. In a possible design, the first message includes at least one session identifier and at least one NAS message, the at least one NAS message has a one-to-one correspondence with at least one session, the NAS message corresponding to the first session in at least one session is used to request the establishment or activation of the first session, and the first session is one of at least one sessions.

[0216] When a terminal device requests the activation of multiple sessions, the terminal device may send an identifier and a corresponding NAS message to (R)AN for each session. For example, if the terminal device requests the activation of sessions A, B, and C, the first message may include the identifier and NAS message A for session A (NAS message A is used to request the activation of session A), the identifier and NAS message B for session B (NAS message B is used to request the activation of session B), and the identifier and NAS message C for session C (NAS message C is used to request the activation of session C).

[0217] In some embodiments, during the process of establishing each session, the SMF corresponding to the session may deliver SMF identification information to the terminal device. Correspondingly, the terminal device receives and stores identification information from each of at least one SMF. The terminal device includes the identification information of the SMF corresponding to each of at least one session in a first message.

[0218] When a terminal device requests to activate multiple sessions, the method performed by the network for each session is the same as the method performed for the first session, and the details will not be explained here again.

[0219] S502.(R)AN sends a second message to the first SMF, and the first SMF receives the second message, which includes the first NAS message and the identifier of the terminal device.

[0220] (R)AN may send a second message to the first SMF based on the identification information of the first SMF. The identifier of the terminal device in the second message may be a permanent or temporary identifier of the terminal device.

[0221] The second message may further include an identifier for the first session, or an identifier for the AMF. For example, (R)AN includes the AMF ID obtained from the third message in the second message and sends the second message to the first SMF.

[0222] When a terminal device requests the activation of multiple sessions, it can be understood that (R)AN may send a second message to the SMF corresponding to each session.

[0223] For example, the second message could be an NG Application Protocol (NGAP) message or a service-oriented message (e.g., Nsmf_PDUSession_CreateSMContext Request).

[0224] Referring to the example above, the first message includes the identifier of session A and NAS message A, the identifier of session B and NAS message B, and the identifier of session C and NAS message C. Session A corresponds to SMF-A, session B corresponds to SMF-B, and session C corresponds to SMF-C. In this case, (R)AN may send second messages to SMF-A, SMF-B, and SMF-C, respectively. The second message sent to SMF-A includes NAS message A, the second message sent to SMF-B includes NAS message B, and the second message sent to SMF-C includes NAS message C. If multiple NA messages correspond to the same SMF, it can be understood that (R)AN may include multiple NAS messages in the same message for transmission, or multiple NAS messages in different messages for transmission. This is not limited to this embodiment of the present application.

[0225] S503. The first SMF approves or rejects the first NAS message based on the mobility restriction information of the terminal device.

[0226] When the first NAS message is used to request the establishment of the first session, it can be understood that the first SMF approving the first NAS message means approving the establishment of the first session. Correspondingly, the first SMF performs the procedures related to the establishment of the first session, for example, configuring control plane resources for the first session (e.g., the first SMF creates the context for the first session) and configuring user plane resources for the first session (e.g., selecting a PCF, establishing a session management policy, selecting a UPF, and establishing an N4 session). For details, please refer to the relevant procedures S203 to S217 shown in Figure 2.

[0227] When the first NAS message is used to request activation of the first session, the first SMF's approval of the first NAS message means that it approves the activation of the first session. Correspondingly, the first SMF performs the procedures related to the activation of the first session, for example, activating the control plane resources of the first session (e.g., the first SMF updates the context of the first session) and configuring the user plane resources of the first session (e.g., selecting a new UPF and establishing a new N4 session). For details, please refer to the relevant procedures S305 to S310 shown in Figure 3.

[0228] In this embodiment of the present application, the mobility restriction information includes, but is not limited to, at least one of the following:

[0229] (1) A fourth piece of information which indicates whether the terminal device is located in an authorized or unauthorized area.

[0230] Specifically, if the first SMF determines, based on the fourth information, that the terminal device is not located in an authorized area or is located in an unauthorized area, the first SMF rejects the first NAS message. If the first SMF determines, based on the fourth information, that the terminal device is located in an authorized area or is not located in an unauthorized area, the first SMF may approve the first NAS message.

[0231] (2) A fifth piece of information which indicates an authorized or unauthorized area of ​​the terminal device.

[0232] Specifically, the first SMF may determine, based on the terminal device's location information and the fifth information, whether the terminal device is located in an authorized area and / or an unauthorized area. Specifically, when the first SMF determines that the terminal device is not located in an authorized area or is located in an unauthorized area, the first SMF rejects the first NAS message. When the first SMF determines that the terminal device is located in an authorized area or is not located in an unauthorized area, the first SMF may approve the first NAS message. The first SMF may obtain the terminal device's location information from the AMF. Alternatively, the first SMF obtains the terminal device's location information based on the second message. For example, the second message may contain the terminal device's location information, or the second message may contain an identifier for (R)AN, and the first SMF obtains the terminal device's location information based on the identifier for (R)AN.

[0233] In some embodiments, permitted or unpermitted areas may be further associated with the data network and / or network slice of the terminal device. For example, the second message further includes a data network identifier and / or a network slice identifier, or the first NAS message in the second message includes a data network identifier and / or a network slice identifier. The data network identifier indicates the data network used by the terminal device, the network slice identifier indicates the network slice used by the terminal device, and the fifth information indicates the permitted or unpermitted area of ​​the terminal device corresponding to the data network and / or network slice. When the first SMF determines, based on the terminal device's location information and the fifth information, that the terminal device is not located in a permitted area or is located in an unpermitted area, the first SMF rejects the first NAS message. If the first SMF determines, based on the terminal device's location information and the fifth information, that the terminal device is located in an authorized area of ​​the terminal device corresponding to the data network and / or network slice included in the second message or the first NAS message, or if the first SMF determines, based on the terminal device's location information and the fifth information, that the terminal device is not located in an unauthorized area of ​​the terminal device corresponding to the data network and / or network slice included in the second message or the first NAS message, the first SMF may approve the first NAS message; otherwise, the first SMF may reject the first NAS message.

[0234] (3) Information number six, which indicates an authorized or unauthorized radio access technology.

[0235] Specifically, authorized wireless access technologies are wireless access technologies that terminal devices are permitted to use when accessing the network, and unauthorized wireless access technologies are wireless access technologies that terminal devices are not permitted to use when accessing the network. Since terminal devices access the network via (R)AN, if the wireless access technology of (R)AN belongs to the authorized wireless access technologies, or if the wireless access technology of (R)AN does not belong to the unauthorized wireless access technologies, the first SMF may approve the first NAS message; otherwise, the first SMF rejects the first NAS message.

[0236] When mobility restriction information includes at least two of the aforementioned items, it can be understood that the first SMF approves the first NAS message only if each of at least two items satisfies the corresponding restriction condition, or rejects the first NAS message if at least one of the two items does not satisfy the corresponding restriction condition.

[0237] For example, if the terminal device is located in an authorized area and the (R)AN wireless access technology belongs to an authorized wireless access technology, the first SMF approves the first NAS message. If the terminal device is located in an authorized area but the (R)AN wireless access technology belongs to an unauthorized wireless access technology, or if the (R)AN wireless access technology belongs to an authorized wireless access technology but the terminal device is located in an unauthorized area, or if the terminal device is located in an unauthorized area and the (R)AN wireless access technology belongs to an unauthorized wireless access technology, the first SMF rejects the first NAS message.

[0238] It should be understood that the aforementioned types of mobility restriction information are merely examples and are not actually limited to them.

[0239] In some embodiments, the first SMF may obtain (e.g., subscribe to or query) the AMF for the terminal device's mobility restriction information based on the AMF identifier. The AMF is either the AMF to which the terminal device is registered or the AMF responsible for managing the terminal device's access. If the second message contains the AMF identifier, the first SMF may directly obtain the terminal device's mobility restriction information from the AMF based on the AMF identifier in the second message, or if the second message does not contain the AMF identifier, the first SMF may obtain the AMF identifier from the terminal context information repository function network element based on the terminal device identifier, which stores the correspondence between the AMF identifier and the terminal device identifier. For example, the terminal device identifier in the second message is a temporary identifier, and the first SMF obtains the AMF identifier from the terminal context information repository function network element based on the terminal device's temporary identifier. In another example, the identifier of the terminal device in the second message is a temporary identifier, and the first SMF first obtains the permanent identifier of the terminal device based on the temporary identifier of the terminal device, and then obtains the AMF identifier from the terminal context information repository function network element based on the permanent identifier of the terminal device.

[0240] In some other embodiments, the first SMF may retrieve (e.g., subscribe to or query) mobility restriction information for a terminal device from a terminal context information repository functional network element (e.g., UDR) based on the terminal device identifier.

[0241] For example, a terminal context information repository function network element stores context data for terminal devices, and this context data includes mobility restriction information. The first SMF sends a query request to the terminal context information repository function network element, which includes the identifier of the terminal device, and is used to request the retrieval of the context data for the terminal device. The terminal context information repository function network element returns the context data for the terminal device to the first SMF based on the identifier of the terminal device, and the first SMF determines the mobility restriction information for the terminal device from the context data. For example, the identifier of the terminal device in the second message is a temporary identifier, and the query request includes the temporary identifier of the terminal device. In another example, the identifier of the terminal device in the second message is a temporary identifier, and the first SMF first retrieves the permanent identifier of the terminal device based on the temporary identifier of the terminal device, and the query request includes the permanent identifier of the terminal device.

[0242] In some embodiments, the approval of the first NAS message by the first SMF may further include the first SMF sending a third NAS message to (R)AN, the third NAS message indicating to the first SMF that it approves the first NAS message, and (R)AN forwarding the third NAS message to a terminal device (e.g., carried in an RRC message). The third NAS message is, for example, a PDU session creation context response (Nsmf_PDUSession_CreateSMContext Response) or a PDU session update context response (Nsmf_PDUSession_UpdateSMContext Response). The rejection of the first NAS message by the first SMF may further include the first SMF sending a fourth NAS message to (R)AN, the fourth NAS message indicating to the first SMF that it has rejected the first NAS message, and (R)AN forwarding the fourth NAS message to the terminal device (e.g., carried in an RRC message). The fourth NAS message is, for example, a PDU session creation context failure (Nsmf_PDUSession_CreateSMContext Failure) message or a PDU session update context failure (Nsmf_PDUSession_UpdateSMContext Failure) message.

[0243] It should be noted that the above description illustrates a specific implementation method for directly exchanging NAS messages between (R)AN and SMF, using an example where (R)AN is directly connected to SMF via a service-oriented interface. In actual application, (R)AN may be further directly connected to another core network element (e.g., UPF, PCF, or NRF) via a service-oriented interface, resulting in (R)AN and the other core network element directly exchanging NAS messages.

[0244] In this embodiment of the present application, (R)AN is directly connected to a core network element (e.g., SMF), thereby enabling (R)AN and the core network element (e.g., SMF) to exchange messages directly without forwarding them through AMF, thereby improving the efficiency of managing and controlling network session-related procedures.

[0245] To better understand the technical solutions in the embodiments of this application, several complete examples are provided below.

[0246] Example 1: Figure 7 is a flowchart of a session establishment method according to one embodiment of this application. This method uses an example in which AMF performs access registration management and mobility management. The method includes the following steps.

[0247] S701. Perform the terminal device registration procedure.

[0248] In the terminal device registration procedure, (R)AN may obtain the AMF selected by the network for the terminal device from a selection function network element (e.g., NRF).

[0249] The AMF or (R)AN may assign a temporary identifier (e.g., UE temporary ID) to a terminal device. The UE temporary ID is used by the (R)AN and core network elements to identify the terminal device.

[0250] In a possible implementation, the AMF may send mobility restriction information to the terminal device. This information includes permitted and / or prohibited areas. When the terminal device UE is in a permitted area, the terminal device UE is permitted to initiate PDU session-related services. In another possible implementation, the AMF may notify (R)AN that the terminal device is in a permitted or prohibited area. Alternatively, the AMF sends a Mobility Restriction List to (R)AN. The list contains information about areas where services are permitted or prohibited, and (R)AN uses the list to determine whether the terminal device is in a permitted or prohibited area.

[0251] If a terminal is in an unauthorized area, (R)AN may decide not to forward certain types of NAS messages (for example, (R)AN may be pre-configured with specific types of NAS messages that (R)AN will or will not forward when a terminal is in an unauthorized area). For example, (R)AN may decide not to forward SM NAS messages (and not to request SMF detection from the NRF). In another example, (R)AN may forward policy NAS messages to PCF network elements.

[0252] In possible implementations, the AMF may determine which types of NAS messages (R)AN will forward or not forward. For example, the AMF may determine which SM NAS messages (R)AN will not forward based on whether the terminal is in an unauthorized area, and the AMF may provide (R)AN with information about which types of NAS messages will be forwarded or not forwarded.

[0253] Optionally, the AMF may further transmit the AMF ID (e.g., the AMF IP address) to the (R)AN, or the AMF may transmit the AMF ID and the UE temporary ID to the UDR.

[0254] Execute the PDU session establishment procedure, including S702.S702a to S702d.

[0255] S702a. The terminal device sends an AN message to (R)AN, and (R)AN receives the AN message from the UE, the AN message containing a PDU session ID (corresponding to the aforementioned identifier of the first session) and a first SM NAS message (corresponding to the aforementioned first NAS message).

[0256] (R)AN can further recognize the type of the first SM NAS message. (R)AN initiates a request to the NRF, the NRF selects an SMF, and the NRF sends the identifier of the selected SMF (e.g., SMF ID) to (R)AN. (R)AN remembers the correspondence between the PDU session ID and the SMF ID (the SMF is responsible for managing the PDU session).

[0257] The first SM NAS message may be a PDU session establishment request message, and the message may include the PDU session ID, the requested DNN, the requested PDU session type, the requested SSC mode, and so on.

[0258] S702b.(R)AN sends a request message to the SMF (corresponding to the second message mentioned above) to request a connection.

[0259] When the AMF sends the AMF ID (e.g., AMF IP address) to (R)AN in S701, the request message may include the PDU session ID, UE temporary ID, the first SM NAS message, and the AMF ID. Optionally, if the AMF changes, (R)AN further notifies the SMF of the new AMF ID.

[0260] When the AMF sends the AMF ID and UE temporary ID to the UDR in S701, the request message may include the PDU session ID, the UE temporary ID, and the first SM NAS message. The SMF may then send the UE temporary ID to the UDR, which determines the AMF ID based on the UE temporary ID and sends the AMF ID to the SMF. Optionally, if the AMF changes, the UDR further notifies the SMF of the new AMF ID.

[0261] After receiving the request message, the SMF may retrieve the terminal's subscription data from the UDM based on the UE temporary ID, and based on the subscription data and the information in the first SM NAS message, may decide whether to authorize the establishment of the PDU session.

[0262] S702c.SMF queries AMF or subscribes to AMF to determine if the terminal is in an authorized area, based on the UE temporary ID and AMF ID. If the terminal is in an unauthorized area, SMF refuses to establish a PDU session. If the terminal is in an authorized area, SMF approves the establishment of a PDU session.

[0263] It can be understood that S702c is an arbitrary step.

[0264] In some embodiments, the DNN that may be included in the first SM NAS message corresponds to a local service, and the SMF may query the AMF to determine whether the terminal is in the LADN. If the terminal is not in the LADN, the SMF refuses to establish a PDU session. If the terminal is in the LADN, the SMF approves the establishment of a PDU session.

[0265] In some embodiments, the SMF may further page idle terminal devices based on their AMF ID.

[0266] After receiving the first SM NAS message, it can be understood that the SMF may refer to the PDU session establishment procedure shown in Figure 2. For example, the SMF may further execute S204, S207a, S207b, S208, S209, S210, etc.

[0267] S702d.SMF sends a response message to (R)AN, which may include a UE temporary ID, N2 SM information, and a second SM NAS message.

[0268] N2 SM information may include the PDU session ID, QoS flow identifier QFI, QoS profile, CN tunnel information, etc. The second SM NAS message may be a PDU session establishment authorization message and may include QoS rules, QoS parameters, IP address information, etc. (R)AN configures the wireless air interface resources of the terminal device based on the N2 SM information and sends the second SM NAS message to the terminal device. (R)AN then sends the PDU session ID, AN tunnel information, and QoS flow authorized for establishment to the SMF.

[0269] S703. After receiving the response message, (R)AN sends an RRC message to the terminal device, which may include a second SM NAS message.

[0270] For example, (R)AN sends an RRC message to the terminal device corresponding to the UE temporary ID based on the UE temporary ID in the response message.

[0271] Perform the S704.PDU session correction procedure.

[0272] In this procedure, the (R)AN (or terminal device) interacts directly with the SMF without the participation of the AMF. For a PDU session correction procedure initiated by the terminal device, the terminal device sends the PDU session ID and a third SM NAS message to the (R)AN, the (R)AN sends the UE temporary ID and a third SM NAS message to the corresponding SMF based on the PDU session ID, and the SMF then sends the N2 SM information and a third SM NAS message to the (R)AN. For a PDU session correction procedure initiated by the SMF, the SMF sends the UE temporary ID and N2 SM information to the (R)AN.

[0273] Furthermore, the network can perform additional state management. For example, after a terminal device enters an idle state, (R)AN may proactively release its connection to the AMF / SMF, or the AMF may notify each SMF, and the AMF and SMF may proactively release their connection service to (R)AN.

[0274] In the aforementioned solution, the AMF performs access registration management and mobility management. The (R)AN decides whether to send SM NAS messages directly to the SMF based on AMF configuration information (e.g., mobility restriction list) or information about the type of NAS message to be forwarded or not forwarded. The SMF learns the AMF ID from the (R)AN or UDR, queries the AMF for terminal device location information (e.g., whether the terminal device is located within an authorized area or LADN), and decides whether to authorize the establishment of a PDU session. This solution can improve the flexibility and management and control efficiency of the PDU session establishment procedure.

[0275] Example 2: Figure 8 is a flowchart of a service request method according to one embodiment of the present application. This method uses an example in which the AMF performs access registration management and mobility management. The method includes the following steps:

[0276] For specific instructions on how to perform terminal device registration (S801), please refer to S701.

[0277] For specific details on the procedure for establishing a PDU session (S802), please refer to S702.

[0278] S803: Perform the Uplink Service Request (SR) procedure. S803 includes the following two actions:

[0279] Method 1: Please refer to S803a to S803c.

[0280] S803a. The terminal device sends an AN message to (R)AN, and (R)AN receives the AN message.

[0281] An AN message includes AN parameters and [PDU session ID, SR message]. The AN parameters may include 5G-S-TMSI. [PDU session ID, SR message] indicates that each PDU session identifier is associated with one SR message. SR = Service Request. The SR message includes the identifier of the PDU session to be activated (PDU session ID) and the PDU session status. It can be understood that the PDU session ID corresponds to the aforementioned first NAS message, and the SR message corresponds to the aforementioned first NAS message. It can be understood that the SR message may be replaced by another message that can be used to activate a PDU session, for example, a PDU session activation message.

[0282] Optionally, in the PDU session establishment procedure, the SMF may send the UE temporary ID, PDU session ID, and SMF ID to the UDR. After receiving the AN message, the (R)AN may obtain the SMF ID corresponding to [UE temporary ID, PDU session ID] from the UDR.

[0283] S803b. The (R)AN sends a request message (corresponding to the aforementioned second message) to each SMF, and the request message includes the SR message and the UE temporary ID.

[0284] Several specific implementations of S803a to S803b are shown below.

[0285] Implementation 1: The RAN sends an access notification / request to the AMF (that is, the AMF performs access control). If the AMF permits terminal access, the (R)AN obtains the SMF ID from the UDR and sends the request message to the SMF. The SMF obtains the AMF ID from the UDR based on the UE temporary ID. In 801, the AMF sends the AMF ID and the UE temporary ID to the UDR, and the UE temporary ID may be a 5G-S-TMSI. Optionally, if the UE temporary ID is not a 5G-S-TMSI, the AMF sends the UE temporary ID to the (R)AN after permitting terminal access.

[0286] Implementation 2: The (R)AN sends an access notification / request to the AMF (that is, the AMF performs access control). If the AMF permits terminal access, the (R)AN obtains the SMF ID from the UDR and sends the request message to the SMF. The (R)AN further sends the AMF ID to the SMF. If the UE temporary ID is not a 5G-S-TMSI, the (R)AN receives the UE temporary ID and the AMF ID from the AMF. If the UE temporary ID is a 5G-S-TMSI, the (R)AN receives the AMF ID from the AMF.

[0287] Implementation 3: (R)AN does not send an access notification / request to the AMF, and (R)AN sends a request message to the SMF. The message further includes an AMF ID. If the UE temporary ID is not a 5G-S-TMSI, (R)AN obtains the AMF ID and the UE temporary ID from the UDR based on the 5G-S-TMSI, and correspondingly, over S801, the AMF sends the 5G-S-TMSI, the UE temporary ID, and the AMF ID to the UDR. If the UE temporary ID is a 5G-S-TMSI, (R)AN obtains the AMF ID from the UDR based on the 5G-S-TMSI, and correspondingly, over S801, the AMF sends the 5G-S-TMSI and the AMF ID to the UDR.

[0288] In these implementations, the SMF may further inquire whether the AMF allows terminal device access based on the AMF ID.

[0289] Implementation 4: (R)AN sends an access notification / request to the AMF (that is, the AMF performs access control). The AMF notifies (R)AN that the terminal is within an allowed area / disallowed area. Alternatively, the AMF sends a mobility restriction list to (R)AN. (R)AN determines that the terminal is within an allowed area / disallowed area based on the mobility restriction list. If the terminal is within a disallowed area, (R)AN does not send a specific type of NAS message to the NF. If the terminal is within an allowed area, (R)AN sends a specific type of NAS message to the SMF.

[0290] In this implementation, the AMF may indicate to (R)AN the specific type of NAS message that is allowed to be forwarded.

[0291] Implementation 5: (R)AN sends an access notification / request to AMF (i.e., AMF performs access control). AMF determines whether the terminal device is in a service area restriction and stores the result in the UDR. SMF learns from the UDR, based on the UE temporary ID, whether the terminal is in an permitted / unpermitted area or LADN.

[0292] S803c.SMF queries or subscribes to AMF to determine whether a terminal is within an authorized area based on the UE temporary ID and AMF ID. Alternatively, SMF subscribes to mobility events from AMF (e.g., whether a terminal is within an authorized area or inside or outside the LADN) based on the UE temporary ID and AMF ID. The UE temporary ID and AMF ID can further be used to page idle terminal devices.

[0293] It can be understood that S803c is an arbitrary step.

[0294] For the steps taken after SMF receives a (R)AN request, please refer to the relevant steps in Figure 2.

[0295] Method 2: Please refer to S803d through S803h.

[0296] S803d. The terminal device first sends AN message 1 (corresponding to the fourth message described above) to (R)AN, the message containing AN parameters and further containing an MM NAS message or registration request message or access request message (corresponding to the second NAS message described above).

[0297] S803e.(R)AN sends MM NAS messages, registration request messages, or access request messages to the AMF.

[0298] S803f.(R)AN receives AMF ID / terminal context information from AMF (for example, a mobility restriction list, or information indicating that the terminal is in an permitted / unpermitted area).

[0299] S803g. The terminal device sends AN message 2 (corresponding to the first message described above) to (R)AN, the message containing AN parameters and [PDU session ID, SR message]. The SR message may be replaced with a PDU session activation message. In this case, the terminal device is already connected, and (R)AN does not need to send an access notification / request to the AMF.

[0300] S803h.(R)AN sends a request message (corresponding to the second message mentioned above) to the SMF, which may include an SR message and a temporary UE ID.

[0301] Referring to Implementation 1, (R)AN may obtain the SMF ID from the UDR and send an SR message to the SMF. The SMF obtains the AMF ID from the UDR based on the UE temporary ID.

[0302] Referring to Implementation 2 or Terminal Device 3, (R)AN may obtain the SMF ID from the UDR and send an SR message to the SMF, and (R)AN may send the AMF ID to the SMF.

[0303] See Implementation 4, (R)AN may determine that a terminal is in an permitted / unpermitted area based on the mobility restriction list or permitted / unpermitted area indication information transmitted by the AMF.

[0304] Referring to Implementation 5, after receiving an MM NAS message / registration message, the AMF may determine whether the terminal device is in a service area limit and store the result in the UDR.

[0305] In the foregoing solution, a terminal device can send a plurality of SR (Scheduling Request) messages, and each SR message corresponds to one PDU (Packet Data Unit) session. After receiving the SR message, the (R)AN (Radio Access Network) acquires the SMF (Session Management Function) corresponding to the PDU session and transmits the SR message to the SMF. After receiving the SR message, the (R)AN transmits an access notification / request to the AMF (Access and Mobility Management Function). If the AMF allows the terminal device to access, the AMF can transmit the SR message to the SMF. The terminal device can first transmit an access request message to the (R)AN, so that the (R)AN can acquire the context information of the terminal from the AMF. Next, the terminal device transmits an SR message to the (R)AN. In this case, the (R)AN does not need to transmit an access request message to the AMF. This solution can improve the flexibility of the service request procedure and the management and control efficiency.

[0306] Example 3: Figure 9 is a flowchart of another session management method according to an embodiment of the present application. The method comprises a session establishment procedure and a service request procedure. Different from Example 1 and Example 2, in Example 3, the AMF performs access registration management, and mobility management is performed independently by respective core network elements.

[0307] S901. For specific implementation of the terminal device registration procedure, please refer to S701.

[0308] S902. A PDU session establishment procedure is performed.

[0309] S902a. A terminal device transmits an AN message (corresponding to the foregoing first message) to a (R)AN, and the (R)AN receives the AN message, wherein the AN message comprises a PDU session ID and a first SM NAS message.

[0310] Optionally, (R)AN recognizes the type of SM NAS message and requests the NRF to select an SMF. The NRF returns the identifier of the selected SMF (e.g., SMF ID) to (R)AN. After obtaining the SMF ID, (R)AN stores the correspondence between the PDU session ID and the SMF ID (the SMF is responsible for managing the PDU session).

[0311] S902b.(R)AN sends a request message (corresponding to the second message described above) to the SMF to request a connection. The request message includes the PDU session ID, the UE temporary ID, and the first SM NAS message. The first SM NAS message may be a PDU session establishment request message and may include the PDU session ID, the requested DNN, the requested PDU session type, the requested SSC mode, etc.

[0312] Method 1: (DNN / S-NSSAI is not distinguished by service area restrictions): The SMF obtains service area restrictions (e.g., permitted area and RAT restrictions) from the UDR based on the UE temporary ID, and the SMF determines whether the terminal device's location satisfies the service area restrictions and approves or rejects the request. For example, if the (R)AN requesting access is within the permitted area (if the SMF is pre-configured with the (R)AN's location information), the request is approved. For example, the SMF obtains the AMF ID from the (R)AN or UDR, obtains the terminal device's location information from the AMF, and approves the request if the terminal device is within the permitted area. For example, the SMF receives a connection request from the (R)AN (corresponding to terminal access using a 3GPP RAT). If the RAT restriction indicates that access cannot be performed using a 3GPP RAT, the SMF rejects the request.

[0313] Method 2: (DNN / S-NSSAI are distinguished by service area restrictions): The SMF obtains the service area restrictions (e.g., permitted / unpermitted areas) corresponding to each DNN / S-NSSAI from the UDR based on the UE temporary ID, and the SMF determines whether the terminal device's location satisfies the service area restrictions corresponding to the requested DNN / S-NSSAI, and approves or rejects the request. For example, if the (R)AN accessed by the terminal device is within the permitted area corresponding to the requested DNN / S-NSSAI (if the SMF is pre-configured with the (R)AN's location information), the request is approved. For example, the SMF obtains the AMF ID from the (R)AN or UDR, obtains the terminal device's location information from the AMF, and approves the request if the terminal device's location is within the permitted area corresponding to the requested DNN / S-NSSAI.

[0314] Perform the S902c.PDU session correction procedure and status management. For specific implementation details, please refer to the relevant explanation in Example 1.

[0315] It can be understood that if a terminal device moves to an area that the (R)AN accessed by the terminal device is not authorized to be in, the SMF will trigger a PDU session release. Specifically, a PDU session release request is sent to the (R)AN. The request includes the UE temporary ID, the UEPDU session ID, and a second SM NAS message. The second SM NAS message may be a PDU session release message.

[0316] When a terminal device needs to perform a service transmission, it initiates a service request to activate the PDU session.

[0317] S903. Execute the service request procedure.

[0318] S903a. The terminal device sends an AN message (corresponding to the first message described above) to (R)AN, and (R)AN receives the AN message. The AN message includes AN parameters and [PDU session ID, SR message]. The AN parameters include 5G-S-TMSI.

[0319] Optionally, (R)AN retrieves the SMF ID corresponding to [UE Temporary ID, PDU Session ID] from the UDR.

[0320] S903b.(R)AN sends a request message (corresponding to the second message mentioned above) to each SMF, the request message including the SR message and the UE temporary ID.

[0321] S903c:SMF determines whether the terminal device is subject to service area restrictions based on information obtained from the UDR, and approves or rejects the request accordingly.

[0322] For specific implementations of S903c, please refer to Implementation 1, Implementation 2, or Implementation 3 of Example 2 mentioned above. Further details will not be explained again here.

[0323] In the aforementioned solution, mobility management is performed independently by each core network element (e.g., SMF). Each core network element obtains service area limits from the UDR and decides whether to approve or reject a PDU session establishment or activation request based on the terminal device's location and service area limits. This improves the flexibility and management and control efficiency of PDU session-related procedures.

[0324] The method provided in the embodiments of this application is described above with reference to the accompanying drawings. The apparatus provided in the embodiments of this application will be described below with reference to the accompanying drawings.

[0325] Based on the same technical concept, embodiments of this application provide a communication device. The device includes a module / unit / means configured to perform a method performed by any network function or entity in embodiments of the above method. The module / unit / means may be implemented by software, hardware, or hardware running the corresponding software.

[0326] For example, see Figure 10. The apparatus 100 may include a transceiver unit 1001 and a processing unit 1002.

[0327] In one example, if the device 100 is an access network element or is located within an access network element, the transceiver unit 1001 is configured to receive a first message from a terminal device, the first message including a first session identifier and a first non-access layer NAS message, the first NAS message being used to request the establishment or activation of the first session corresponding to the identifier, and to send a second message to a first session management function network element, the second message including the first NAS message and the terminal device identifier. Optionally, the processing unit 1002 is configured to determine the second message based on the first message.

[0328] In another example, if device 100 is a first session management function network element or is located within a first session function network element, transceiver unit 1001 is configured to receive a second message from the access network element, the second message including a first NAS message and an identifier for a terminal device, the first NAS message being used to request the establishment or activation of a first session, and processing unit 1002 is configured to approve or reject the first NAS message based on the mobility restriction information of the terminal device.

[0329] In yet another example, if the device 100 is a registration function network element or is located within a registration function network element, the transceiver unit 1001 is configured to receive an access request message from the access network element, which is used to request a terminal device to connect to the registration function network element (or network) on which the device is located, and to send a third message to the access network element, which includes at least one piece of information, at least one piece of information, which is used by the access network element to determine whether to forward the first NAS message. Optionally, the processing unit 1002 is configured to determine the third message based on the access request message.

[0330] In yet another example, if the device 100 is a terminal device or is located within a terminal device, the processing unit 1002 is configured to generate a first message, and the transceiver unit 1001 transmits the first message to an access network element, the first message comprising at least one session identifier and at least one NAS message, the at least one NAS message having a one-to-one correspondence with at least one session, and the NAS message corresponding to each of the at least one session being used to request the establishment or activation of the session.

[0331] Please understand that all relevant details of the steps in the embodiments of the method described above may be referenced in the functional description of the corresponding functional module. Further details will not be explained again here.

[0332] In practical implementation, the device may have multiple product forms. Several possible product forms are described below.

[0333] Please refer to Figure 11. Embodiments of the present application further provide a communication device 110. It may be understood that the communication device 110 includes the necessary forms of technical means, for example, modules, units, elements, circuits, or interfaces that are appropriately configured together to implement the solution. The communication device 110 may be any network function or entity in the embodiments of the methods described above, or a component (e.g., a chip) in these functions and entities, and implements the method performed by any network function or entity in the embodiments of the methods described above.

[0334] The communication device 110 includes one or more processors 111. The processors 111 may be general-purpose processors, dedicated processors, etc. For example, the processor may be a baseband processor or a central processing unit. The baseband processor may be configured to process communication protocols and communication data. The central processing unit may be configured to control the communication device (e.g., a RAN node, terminal, or chip), execute software programs, and process data from the software programs.

[0335] In a possible design, the processor 111 may include a program 113 (sometimes called code or instructions). The program 113 may be executed on the processor 111, and as a result, the communication device 110 performs the method performed by any network function or entity in the embodiments of the method described above.

[0336] In yet another possible design, the communication device 110 includes circuitry (not shown in Figure 11) configured to perform functions of any network function or entity performed in the embodiments of the method described above.

[0337] In a specific implementation, the communication device 110 may include one or more memories 112. The memories may store a program 114 (sometimes called code or instructions). The program 114 may be executed on the processor 111, and as a result, the communication device 110 performs any method performed by a network function or entity in the embodiments of the method described above.

[0338] In some embodiments, the processor 111 and / or memory 112 may include AI modules 117 and 118, which are configured to perform AI-related functions. The AI ​​modules may be implemented by software, hardware, or a combination of software and hardware. For example, the AI ​​module may include an RIC module. For example, the AI ​​module may be a near real-time RIC or a non-real-time RIC.

[0339] In a specific implementation, the processor 111 and / or memory 112 may store further data. The processor and memory may be located separately or integrated together.

[0340] The communication device 110 may further include a transceiver 115 and / or an antenna 116. The processor 111 may also be referred to as a processing unit and controls the communication device (e.g., a RAN node or terminal). The transceiver 115 may also be referred to as a transceiver unit, transceiver machine, transceiver circuit, transceiver, etc., and is configured to perform the transceiver function of the communication device via the antenna 116.

[0341] It should be understood that the processor referred to in this embodiment of the present application may be implemented in hardware or software. When the processor is implemented in hardware, it may be a logic circuit, an integrated circuit, etc. When the processor is implemented in software, it may be a general-purpose processor and may be implemented by reading software code stored in memory.

[0342] For example, the processor may be a Central Processing Unit (CPU), or another general-purpose processor, a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or another programmable logic device, discrete gate, transistor logic device, discrete hardware component, etc. The general-purpose processor may be a microprocessor, and the processor may be any conventional processor, etc.

[0343] It should be understood that the memories referred to in the embodiments of this application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (Erasable PROM, EPROM), electrically erasable programmable read-only memory (Electrically EPROM, EEPROM), or flash memory. Volatile memory may be random access memory (RAM) used as an external cache. Through a non-limiting but illustrative description, many forms of RAM may be used, such as static random access memory (Static RAM, SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), double data rate synchronous dynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), enhanced synchronous dynamic random access memory (Enhanced SDRAM, ESDRAM), synchronous link dynamic random access memory (Synchlink DRAM, SLDRAM), and direct rambus dynamic random access memory (Direct Rambus RAM, DR RAM).

[0344] Note that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or another programmable logic device, discrete gate, transistor logic device, or discrete hardware component, memory (storage module) may be integrated into the processor.

[0345] Please note that the memories described herein are intended to include, but are not limited to, these memories and any other suitable type of memory.

[0346] Based on the same technical concept, embodiments of the present application further provide a computer-readable storage medium containing a program or instruction. When the program or instruction is executed on the computer, the method performed by any network function or entity in the embodiments of the method described above is performed.

[0347] Based on the same technical concept, embodiments of this application further provide a computer program product including instructions. The computer program product stores instructions. When the instructions are executed on a computer, any method performed by a network function or entity in the embodiments of the method described above is performed.

[0348] Based on the same technical concept, embodiments of the present application further provide a chip, which may include a processor and may further include memory (or the chip may be coupled to memory). The processor executes program instructions in memory to perform a method performed by any network function or entity in the embodiments of the methods described above. "Coupling" means that two components are coupled to each other directly or indirectly. For example, coupling may mean an electrical connection between two components.

[0349] Those skilled in the art should understand that embodiments of this application may be provided as methods, systems, or computer program products. Accordingly, this application may take the form of hardware-only embodiments, software-only embodiments, or embodiments combining software and hardware. Furthermore, this application may take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, magnetic disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0350] This application will be described with reference to flowcharts and / or block diagrams of the methods, devices (systems), and computer program products described herein. It should be understood that computer program instructions may be used to implement each step and / or block in the flowcharts and / or block diagrams, as well as combinations of steps and / or blocks in the flowcharts and / or block diagrams. These computer program instructions may be provided to a general-purpose computer, a dedicated computer, an embedded processor, or a processor of any other programmable data processing device, so as to generate a machine, where instructions executed by the processor of the computer or any other programmable data processing device generate a device for implementing one or more steps in the flowchart and / or one or more blocks in the block diagram.

[0351] These computer program instructions may be stored in computer-readable memory that can instruct a computer or any other programmable data processing device to operate in a specific manner, and as a result, the instructions stored in computer-readable memory generate artifacts that include an instruction unit. The instruction unit implements a specific function in one or more steps in a flowchart and / or in one or more blocks in a block diagram.

[0352] Computer program instructions may, alternatively, be loaded onto a computer or another programmable data processing device, resulting in a series of operations and steps being executed on the computer or another programmable device to produce the processing implemented by the computer. Thus, instructions executed on the computer or another programmable device provide steps for implementing a particular function in one or more steps in a flowchart and / or one or more blocks in a block diagram.

[0353] Clearly, a person skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Thus, this application is intended to cover such modifications and variations to this application, provided that such modifications and variations fall within the scope of the claims of this application and the equivalent art.

Claims

1. A session management method, The access network element receives a first message from a terminal device, the first message comprising a first session identifier and a first non-access layer NAS message, the first NAS message being used to request the establishment or activation of the first session corresponding to the identifier, The access network element transmits a second message to the first session management function network element, wherein the second message includes the first NAS message and the identifier of the terminal device. A method that includes this.

2. Before the access network element transmits the second message to the first session management function network element, the method The access network element receives a third message from a registration function network element, the third message includes at least one piece of information, and the registration function network element is a registration function network element to which the terminal device is registered. The access network element transmits the second message to the first session management function network element. The method according to claim 1, comprising sending the second message to the first session management function network element based on the at least one piece of information by the access network element.

3. The at least one piece of information includes a first piece of information which indicates that the terminal device is located in an authorized area or not in an unauthorized area, or the first piece of information which indicates an authorized area and / or an unauthorized area. The access network element transmits the second message to the first session management function network element based on the at least one piece of information, The method according to claim 2, wherein the access network element transmits the second message to the first session management function network element if the terminal device is located in an authorized area or not in an unauthorized area.

4. The aforementioned at least one piece of information includes a second piece of information, The second information indicates an authorized message type, and the access network element sending the second message to the first session management function network element based on the at least one piece of information includes, if the authorized message type includes a message type corresponding to the first NAS message, the access network element sending the second message to the first session management function network element, or The method according to claim 2, wherein the second information indicates an unauthorized message type, and the access network element transmits the second message to the first session management function network element based on the at least one piece of information, and the access network element transmits the second message to the first session management function network element if the unauthorized message type does not include a message type corresponding to the first NAS message.

5. The at least one piece of information includes a third piece of information, the third piece of information indicating whether the terminal device is permitted to perform access, The access network element transmits the second message to the first session management function network element based on the at least one piece of information, The method according to any one of claims 2 to 4, wherein if the third information indicates that the terminal device is permitted to perform access, the access network element transmits the second message to the first session management function network element.

6. The method according to any one of claims 2 to 5, wherein the third message further includes an identifier for the registration function network element, and the second message further includes the identifier for the registration function network element.

7. The first NAS message is used to request the establishment of the first session corresponding to the identifier, the first NAS message is a session establishment request message, and the first NAS message includes the identifier of the first session, After the access network element receives the first message from the terminal device, and before the access network element transmits the second message to the first session management function network element, the method The access network element transmits a first request to a selection function network element, the first request being used to request the selection of a session management function network element for the first session. The access network element receives a first response from the selection function network element, the first response including identification information of the first session management function network element, further comprising: The access network element transmits the second message to the first session management function network element. The method according to any one of claims 1 to 6, comprising sending the second message to the first session management function network element based on the identification information of the first session management function network element by the access network element.

8. The first NAS message is used to request the establishment of the first session corresponding to the identifier, the first NAS message is a session establishment request message, and the first NAS message includes the identifier of the first session, Before the access network element receives the first message from the terminal device, the method The method according to any one of claims 2 to 6, further comprising transmitting an access request message to the registration function network element by the access network element, wherein the third message is a response message to the access request message.

9. The first NAS message is used to request activation of the first session corresponding to the identifier, the first NAS message is a service request message or a session activation request message, and the first NAS message includes the identifier of the first session, The access network element transmits the second message to the first session management function network element. The access network element obtains the identification information of the first session management function network element, The method according to any one of claims 1 to 6, comprising sending the second message to the first session management function network element based on the identification information of the first session management function network element by the access network element.

10. The access network element obtains the identification information of the first session management function network element, The access network element transmits a second request to the terminal context information repository function network element, the second request being used to query the session management function network element corresponding to the first session, The method according to claim 9, wherein the access network element receives a second response from the terminal context information repository function network element, the second response comprising the identification information of the first session management function network element.

11. The first message includes the identification information of the first session management function network element, The access network element obtains the identification information of the first session management function network element, The method according to claim 9, comprising obtaining the identification information of the first session management function network element from the first message using the access network element.

12. The first NAS message is used to request activation of the first session corresponding to the identifier, the first NAS message is a service request message or a session activation request message, and the first NAS message includes the identifier of the first session, The aforementioned method, The method according to any one of claims 2 to 6, further comprising the access network element sending an access request message to the registration function network element before the access network element receives the third message from the registration function network element, wherein the access request message includes the identifier of the terminal device, and the third message is a response message to the access request message.

13. The access network element transmits the access request message to the registration function network element. The method according to claim 12, wherein after the access network element receives the first message from the terminal device, the access network element transmits the access request message to the registration function network element.

14. Prior to the access network element receiving the first message from the terminal device, the method further includes the access network element receiving a fourth message from the terminal device, the fourth message comprising a second NAS message, the second NAS message being used to request access to the network or activation of a control plane connection. The method according to claim 12, wherein the access network element transmits the access request message to the registration function network element, which includes transmitting the access request message to the registration function network element based on the fourth message, the access request message includes the second NAS message.

15. The first message includes an identifier for at least one session and at least one NAS message, the at least one NAS message having a one-to-one correspondence with the at least one session, the NAS message corresponding to the first session in the at least one session being used to request the establishment or activation of the first session, and the first session being any one of the at least one sessions. The access network element transmits the second message to the first session management function network element. The method according to any one of claims 9 to 14, comprising transmitting the second message to a session management function network element corresponding to each session via the access network element.

16. A session management method, wherein the method is The terminal device generates the first message, The terminal device transmits the first message to an access network element, wherein the first message includes an identifier for at least one session and at least one NAS message, the at least one NAS message has a one-to-one correspondence with the at least one session, and the NAS message corresponding to each of the at least one sessions is used to request the establishment or activation of the session. A method that includes this.

17. The method according to claim 16, wherein the first message further includes identification information for at least one session management function network element, the identification information for the at least one session management function network element is in a one-to-one correspondence with the at least one session, and each of the at least one session management function network element is responsible for managing the session corresponding to the identification information for the session management function network element.

18. The aforementioned method, The method according to claim 17, further comprising the terminal device receiving the identification information of the session management function network element from each of the at least one session management function network element.

19. Before the terminal device sends the first message, the method: The method according to any one of claims 16 to 18, further comprising transmitting a fourth message to the access network element by the terminal device, the fourth message comprising a second NAS message, the second NAS message being used to request access to the network or activation of a control plane connection.

20. A communication device comprising a module or unit configured to perform the method described in any one of claims 1 to 15, or a module or unit configured to perform the method described in any one of claims 16 to 19.

21. A communication device including a processor, wherein the processor is coupled to a memory, the memory is configured to store a program or instruction, and when the program or instruction is executed by the processor, the communication device is made to perform the method according to any one of claims 1 to 15, or the communication device is made to perform the method according to any one of claims 16 to 19.

22. A computer-readable storage medium, wherein the storage medium stores a computer program or instruction, and when the computer program or instruction is executed by a communication device, the method according to any one of claims 1 to 15 or the method according to any one of claims 16 to 19 is carried out.

23. A chip comprising a processor, wherein the processor is configured to execute program instructions in memory, perform the method according to any one of claims 1 to 15, or perform the method according to any one of claims 16 to 19.

24. A communication system comprising communication equipment and terminal devices, A communication system wherein the communication device is configured to perform the method according to any one of claims 1 to 15, and the terminal device is configured to perform the method according to any one of claims 16 to 19.

25. A computer program product including instructions, wherein the computer program product stores the instructions, and when the instructions are executed on a computer, causes the computer to perform the method according to any one of claims 1 to 15, or causes the computer to perform the method according to any one of claims 16 to 19.

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