Communication method, communication apparatus, chip, and computer-readable storage medium

Abstract

Embodiments of the present application provide a communication method, a communication apparatus, a chip, and a computer-readable storage medium. The method comprises: a first service session management function receiving a first message from a first mobility management function, the first message being used to request switching a terminal device from a second service session management function to the first service session management function, and each service session management function being used to manage multiple sessions of the terminal device; sending a second message to the second service session management function, the second message being used to acquire contexts of the multiple sessions of the terminal device; receiving a third message from the second service session management function, the third message comprising the contexts of the multiple sessions; and on the basis of the contexts of the multiple sessions, updating the multiple sessions. The present application can effectively reduce signaling overhead and lower switching latency.

Description

Communication method, communication device, chip and computer readable storage medium

[0001] The present application claims priority to the Chinese patent application No. 202411098053.1, filed on August 9, 2024, with the State Intellectual Property Office of China, and entitled "Communication method, communication device, chip and computer readable storage medium", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, in particular to a communication method, a communication device, a chip and a computer readable storage medium. BACKGROUND

[0003] In a mobile communication system, a terminal device is often in a constant moving state. In order to maintain the call quality and the continuity of data transmission during the movement of the terminal device, such as the user using the terminal device to make a call while walking or using the terminal device to watch a video on the subway, a mobility management process such as handover needs to be performed according to the service of the user. Since the internet protocol (IP) itself does not support mobility, in order to keep the IP address of the terminal device unchanged during the movement, the mobile communication system adopts the mechanism of mobile IP, and sets up two nodes of an access gateway and an IP anchor point, wherein the anchor point remains unchanged in the mobile handover, and the service area of the access gateway. When the terminal device moves across the service area of the access gateway, the access gateway connected by the terminal device needs to be switched. At the same time, in the iterative development process of the mobile communication network, the construction of the communication network is gradually realized, which leads to the fact that some areas can use the future communication network to provide services for the terminal device, while the remaining areas can only use the communication network before iteration, such as the 4th generation (4th generation, 4G) communication network, to provide services for the terminal device. When the terminal device moves in the areas served by different communication networks, the access gateway in the communication network connected by the terminal device needs to be switched.

[0004] In the above-mentioned mobility management process, the session of the terminal device is triggered to be updated, however, when updating the session, a large amount of signaling needs to be transmitted, which not only makes the signaling overhead large, but also leads to a long handover delay of the terminal device. Therefore, how to reduce the signaling overhead and reduce the handover delay has become one of the problems to be solved. SUMMARY

[0005] The embodiments of the present application provide a communication method, a communication device, a chip and a computer readable storage medium, which can effectively reduce the signaling overhead and reduce the handover delay.

[0006] In a first aspect, an embodiment of the present application provides a communication method applied to a first service session management function, the method comprising: receiving a first message from a first mobility management function, the first message being used to request switching of a terminal device from a second service session management function to the first service session management function, the service session management function being used to manage multiple sessions of the terminal device; sending a second message to the second service session management function, the second message being used to acquire contexts of the multiple sessions of the terminal device; receiving a third message from the second service session management function, the third message comprising the contexts of the multiple sessions of the terminal device; and updating the multiple sessions based on the contexts of the multiple sessions.

[0007] The existing mobility management procedure is performed in a session granularity, that is, a context of one session of the terminal device managed by the second service session management function is acquired each time, and the one session is updated. If the second service session management function manages multiple sessions of the terminal device, the procedure needs to be performed multiple times, that is, the request message is sent to the second service session management function multiple times for the multiple sessions, which not only increases signaling overhead, but also reduces the processing efficiency of the second service session management function, thereby causing a long switching delay of the terminal device. The method provided in the embodiment of the present application can perform the mobility management procedure in a terminal device granularity, that is, the contexts of the multiple sessions of the terminal device are requested by the second message, and the multiple sessions are updated. As can be seen, the number of signaling interactions can be reduced by the embodiment of the present application, thereby effectively reducing signaling overhead, improving the processing efficiency of the second service session management function, and reducing the switching delay of the terminal device.

[0008] In a possible implementation, the second message comprises context identifiers of the multiple sessions of the terminal device, the context identifiers being used to indicate the multiple sessions of the terminal device on the second service session management function.

[0009] In this way, the contexts of the multiple sessions of the terminal device indicated by the context identifiers can be requested by the context identifiers comprised in the second message.

[0010] In a possible implementation, the context identifiers comprise information of the second service session management function and identification information used to indicate the multiple sessions of the terminal device.

[0011] In this way, the second service session management function can be confirmed by the information of the second service session management function, thereby ensuring accurate transmission of the second message. The contexts of the multiple sessions of the terminal device can be accurately confirmed by the second service session management function by the identification information used to indicate the multiple sessions of the terminal device.

[0012] In a possible implementation, the identification information for indicating the multiple sessions of the terminal device comprises one or more of the following: identification information of the terminal device, session identification of the multiple sessions, session context identification of the multiple sessions, tunnel endpoint identifier of the multiple sessions, or packet data network (PDN) connection identification corresponding to the multiple sessions.

[0013] In a possible implementation, the first message comprises the context identification and first location information, and the first location information is used to indicate the location of the terminal device.

[0014] In this way, the first service session management function can be triggered to perform the step of sending the second message through the first message.

[0015] In a possible implementation, the context of the multiple sessions comprises tunnel information of the user plane function corresponding to the multiple sessions; and the step of updating the multiple sessions based on the context of the multiple sessions comprises: selecting a first service user plane function based on the first location information; sending the tunnel information of the user plane function corresponding to the multiple sessions to the first service user plane function; and sending the tunnel information of the first service user plane function to the session management function corresponding to the multiple sessions.

[0016] In this way, after selecting the first service user plane function, the first service session management function can establish a user plane tunnel between the first service user plane function and the user plane function corresponding to the multiple sessions by sending the tunnel information of the user plane function corresponding to the multiple sessions to the first service user plane function, and sending the tunnel information of the first service user plane function to the session management function corresponding to the multiple sessions.

[0017] In a possible implementation, the session management function corresponding to the multiple sessions comprises a first session management function and a second session management function; and the step of sending the tunnel information of the first service user plane function to the session management function corresponding to the multiple sessions comprises: sending first tunnel information of the first service user plane function to the first session management function; and sending second tunnel information of the first service user plane function to the second session management function.

[0018] In this way, when the session management functions corresponding to the multiple sessions include a first session management function and a second session management function, the first service user plane function can allocate different tunnels (i.e., first tunnel information and second tunnel information) of the first service user plane function to the sessions under different session management functions respectively, and then send the tunnels to the corresponding session management functions by the first service session management function, so as to realize session isolation and facilitate efficient and accurate management of multiple sessions. For example, the multiple sessions are any one or more of a home network session, a private network session, a public network session, and a local network session, and the sessions correspond to respective session management functions. The first service user plane function can allocate respective tunnels corresponding to each of the sessions, so as to realize session isolation.

[0019] In a possible implementation, the service session management function can be an intermediate session management function (I-SMF) or a local session management function (L-SMF), and the I-SMF or the L-SMF supports management of multiple sessions of the terminal device.

[0020] In a possible implementation, the service session management function is further configured to select session management functions corresponding to the multiple sessions. For example, when the service session management function receives a creation message of a first session, the service session management function selects a first session management function for the first session, and requests the first session management function to create the first session. For another example, when the service session management function receives a creation message of a second session, the service session management function selects a second session management function for the second session, and requests the second session management function to create the second session.

[0021] In this way, when a new service needs to be deployed or added, a policy of selecting a session management function supporting the new service can be configured on the service session management function, so that the service session management function selects the session management function based on the policy, and the mobility management function does not need to be modified, which can effectively avoid affecting multiple access network devices connected to the mobility management function when the mobility management function is modified.

[0022] In a possible implementation, the service session management function is collocated with a control plane serving gateway (SGW-C), and the session management function is collocated with a corresponding control plane PDN gateway (PGW-C), and the session management functions corresponding to different sessions are different, and different session management functions are collocated with corresponding PGW-Cs.

[0023] In a second aspect, an embodiment of the present application provides a communication method applied to a second service session management function, the method comprising: receiving a second message from a first service session management function, the second message being used to acquire contexts of multiple sessions of a terminal device; and sending a third message to the first service session management function, the third message comprising the contexts of the multiple sessions of the terminal device; wherein the service session management function is used to manage the multiple sessions of the terminal device.

[0024] The existing mobility management procedure is executed in a session granularity, that is, the second service session management function returns the context of one session after receiving a request for acquiring the context of the one session each time, so as to update the one session. If the second service session management function manages multiple sessions of the terminal device, the procedure needs to be executed multiple times, that is, the second service session management function returns the contexts of different sessions multiple times for the multiple sessions, which not only increases the signaling overhead, but also reduces the processing efficiency of the second service session management function, thereby causing a long switching delay of the terminal device. The method provided in the embodiment of the present application can execute the mobility management procedure in a terminal device granularity, that is, the contexts of the multiple sessions of the terminal device are returned through the third message, so as to update the multiple sessions. As can be seen, the embodiment of the present application can effectively reduce the signaling overhead and improve the processing efficiency of the second service session management function by reducing the number of signaling interactions, and reduce the switching delay of the terminal device.

[0025] In a possible implementation, the second message comprises context identifiers of the multiple sessions of the terminal device, and the context identifiers are used to indicate the multiple sessions of the terminal device on the second service session management function.

[0026] In a possible implementation, the context identifiers comprise information of the second service session management function and identification information used to indicate the multiple sessions of the terminal device.

[0027] In a possible implementation, the identification information used to indicate the multiple sessions of the terminal device comprises one or more of the following: identification information of the terminal device, session identifiers of the multiple sessions, session context identifiers of the multiple sessions, tunnel endpoint identifiers of the multiple sessions, or PDN connection identifiers corresponding to the multiple sessions.

[0028] In a possible implementation, the service session management function can be an I-SMF or an L-SMF, and the I-SMF or the L-SMF supports managing the multiple sessions of the terminal device.

[0029] In a possible implementation, the service session management function is further used to select session management functions corresponding to the multiple sessions.

[0030] In a possible implementation, the service session management function is collocated with the SGW-C, and the session management function is collocated with the corresponding PGW-C, wherein the session management functions corresponding to different sessions are different, and the different session management functions are collocated with the corresponding PGW-C.

[0031] In a third aspect, an embodiment of the present application provides a communication method applied to a first mobility management function, the method comprising: selecting a first service session management function based on first location information, the first location information being used to indicate a location of a terminal device; and sending a first message to the first service session management function, the first message being used to request switching of the terminal device from a second service session management function to the first service session management function, the service session management function being used to manage multiple sessions of the terminal device.

[0032] The first mobility management function can first select the first service session management function based on the first location information, and then trigger the switching of the service session management function by sending the first message to the first service session management function, so that the first service session management function updates the multiple sessions.

[0033] In a possible implementation, the first message comprises context identifiers of the multiple sessions of the terminal device and the first location information, and the context identifiers are used to indicate the multiple sessions of the terminal device on the second service session management function.

[0034] In this way, the first service session management function receiving the first message can send a second message comprising the context identifiers to the second service session management function based on the context identifiers, and the first service session management function can select a service user plane function capable of providing services for the terminal device according to the first location information.

[0035] In a possible implementation, before the selecting of the first service session management function based on the first location information, the method further comprises: receiving a fourth message sent by a second mobility management function, the fourth message comprising the context identifiers and the first location information.

[0036] In this way, the first mobility management function can receive the context identifiers and the first location information from the second mobility management function, the second mobility management function providing the mobility management function for the terminal device before the terminal device moves, and the first mobility management function providing the mobility management function for the terminal device after the terminal device moves.

[0037] In a possible implementation, the mobility management function can be an access and mobility management function (AMF) or a mobility management entity (MME).

[0038] In a possible implementation, the context identifier includes information of the second service session management function.

[0039] In this way, the first mobility management function receiving the information of the second service session management function can send the information of the second service session management to the first service session management function, so that the first service session management function can send a second message to the second service session management function.

[0040] In a possible implementation, the context identifier includes information of the second service session management function and identification information indicating multiple sessions of the terminal device.

[0041] In a possible implementation, the identification information indicating multiple sessions of the terminal device includes one or more of identification information of the terminal device, session identifiers of the multiple sessions, session context identifiers of the multiple sessions, tunnel endpoint identifiers of the multiple sessions, or PDN connection identifiers corresponding to the multiple sessions.

[0042] In a possible implementation, the service session management function can be an I-SMF or an L-SMF, and the I-SMF or the L-SMF supports management of multiple sessions of the terminal device.

[0043] In a possible implementation, the service session management function is further configured to select session management functions corresponding to the multiple sessions.

[0044] In a possible implementation, the service session management function is integrated with an SGW-C, and the session management functions are integrated with corresponding PGW-Cs, where the session management functions corresponding to different sessions are different, and the different session management functions are integrated with corresponding PGW-Cs.

[0045] In a fourth aspect, an embodiment of the present application provides a communication apparatus, including a processor and a memory, the processor and the memory being coupled; the processor is configured to implement the method in any one of the first aspect to the third aspect.

[0046] In a fifth aspect, an embodiment of the present application provides another communication apparatus including a processor and a memory, the processor and the memory being coupled; the processor is configured to implement the method in any one of the first aspect to the third aspect.

[0047] In a sixth aspect, the present application provides a chip, which comprises a processor and an interface, the interface is configured to receive or output signals, and the processor is configured to execute code instructions to implement the method according to any one of the first aspect to the third aspect.

[0048] In a seventh aspect, the present application provides a computer readable storage medium, which stores a computer program, when the computer program is invoked by a computer, the computer executes the method according to any one of the first aspect to the third aspect.

[0049] In an eighth aspect, the present application provides a computer program product, when the computer program product is read and executed by a computer, the computer executes the method according to any one of the first aspect to the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0050] FIG. 1 is a schematic diagram of a typical architecture of a communication system;

[0051] FIG. 2 is a schematic diagram of an architecture of a future communication system according to an embodiment of the present application;

[0052] FIG. 3 is a schematic diagram of an architecture of a converged communication system according to an embodiment of the present application;

[0053] FIG. 4 is a schematic diagram of a flow of a communication method according to an embodiment of the present application;

[0054] FIG. 5 is a schematic diagram of a function switching involved in mobility management in a future communication system according to an embodiment of the present application;

[0055] FIG. 6 is a schematic diagram of an interaction flow of mobility management according to an embodiment of the present application;

[0056] FIG. 7 is a schematic diagram of a function switching involved in mobility management in a converged communication system according to an embodiment of the present application;

[0057] FIG. 8 is a schematic diagram of another interaction flow of mobility management according to an embodiment of the present application;

[0058] FIG. 9 is a schematic diagram of a function switching involved in mobility management in a converged communication system according to an embodiment of the present application;

[0059] FIG. 10 is a schematic diagram of another interaction flow of mobility management according to an embodiment of the present application;

[0060] FIG. 11 is a schematic diagram of a structure of a communication apparatus according to an embodiment of the present application;

[0061] FIG. 12 is a schematic diagram of another structure of a communication apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0062] The embodiments of the present application will be described below with reference to the accompanying drawings.

[0063] The terms "first", "second", "third", and "fourth" and the like in the description and in the claims of the present application and the accompanying drawings are used to distinguish between similar objects, not necessarily described in a particular order. Also, the terms "comprise", "have" and any variations thereof are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or apparatus that comprises a list of steps or units is not limited to the listed steps or units, but can optionally further include other steps or units not listed or can optionally further include other steps or units inherent to such processes, methods, products or apparatus.

[0064] It should be understood that in the present application, "at least one" means one or more, and "multiple" means two or more. "And / or" is used to describe the relationship between the associated objects, which means that there can be three relationships, for example, "A and / or B" can mean that only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally represents a "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c can mean a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0065] The method provided by the embodiments of the present application can be applied to a fifth generation (5th generation, 5G) communication system, a 5G-Advanced (5G-A) communication system and the like. Alternatively, the method provided by the embodiments of the present application can be applied to a future communication system, such as a fusion communication system with a 4G communication system.

[0066] For ease of understanding, the typical architecture of a communication system will be introduced first as follows:

[0067] Figure 1 shows a typical architecture of a communication system, as shown in Figure 1, the communication system comprises a terminal device (user equipment, UE), a radio access network (RAN), a data network (DN), a user plane function (UPF), an AMF, a session management function (SMF), an authentication server function (AUSF), a network slice selection function (NSSF), a network Exposure Function (NEF), a NF repository function (NRF), a unified data management (UDM), a policy control function (PCF), and an application function (AF). Among them:

[0068] UE: is the entrance for mobile users to interact with the network, which can provide basic computing power, storage capacity, display business windows to users, and accept user operation input. The UE is used to establish a signal connection with the RAN using air interface technology, a data connection, so as to transmit data to the RAN. For example, the UE can be a mobile phone, a pad, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in unmanned automatic driving, a wireless terminal device in remote medical treatment, a wireless terminal device in smart grid, a wireless terminal device in transportation safety, a wireless terminal device in smart city, or a wireless terminal device in smart home, etc.

[0069] RAN: includes at least one access network device, similar to the base station in the traditional network, deployed near the UE, provides access functions for authorized users in a specific area, and can determine different quality transmission tunnels according to the level of users, business needs, etc. Access network device can manage its own resources, rationally use, provide access services for UE on demand, and be responsible for forwarding control signaling and user data between UE and various functions (such as AMF and UPF, etc.) in the core network. For example, the access network device can include a next generation evolved node B (ng-eNB) in a 5G communication system, a next generation node B (gNB) in a 5G communication system, etc., without specific limitation. Alternatively, the access network device can also include an access point (AP) in a WLAN, a broadband remote access server (BRAS), a relay station, a communication device in a future evolved PLMN network, a communication device in an NTN network, etc.

[0070] DN: used to provide service services for users, usually, the client is located in the UE, and the server is located in the DN.

[0071] Among the above UPF, AMF, SMF, AUSF, NSSF, NEF, NRF, UDM, PCF and AF, the UPF is the function of the user plane, and the rest are network functions of the control plane. The interaction between the functions of the control plane adopts the service call mode to replace the point-to-point communication mode in the traditional architecture. In the service-oriented architecture, the functions of the control plane will open services to other functions of the control plane for other functions of the control plane to call; in point-to-point communication, there will be a specific set of messages between the communication interfaces of the control plane functions, which can only be used by the control plane functions at both ends of the interface when communicating.

[0072] Specifically, the functions of these functions are as follows:

[0073] UPF: performs data packet routing and transmission according to the routing rules of the SMF, for example, sends uplink data to the DN, and forwards downlink data to the RAN. It can also perform data packet detection, service usage reporting, quality of service (QoS) processing, uplink data packet detection, downlink data packet storage, etc.

[0074] AUSF: performs security authentication for the UE, such as generating keys and other information required for authentication.

[0075] AMF: performs access management, mobility management, reachability management, access authentication and authorization, etc. for the UE.

[0076] SMF: Session management for UE, including establishment, modification and release of session resources, including session QoS, session path and routing rules, etc., and the SMF is also responsible for the selection of UPF.

[0077] NSSF: Select network slices for UE, so as to realize logical isolation of different services between UE and DN.

[0078] NEF: Open network functions for third parties through northbound API interface.

[0079] NRF: Provides storage and selection functions of network function entity information for the rest of the functions.

[0080] UDM: User subscription context management, including supporting authentication and key agreement mechanism in authentication credential processing, user identity processing, access authorization, registration and mobility management, subscription management, short message management, etc.

[0081] PCF: User policy management, for example, it can provide policy rule information for AMF and SMF, etc.

[0082] AF: Application management, provides application layer information, and can interact with the policy framework through NEF or directly interact with the policy framework to request policy decision, etc.

[0083] Specifically, the functions of each interface in FIG. 1 are as follows:

[0084] N1 interface is the interface between AMF and UE, which can be used to transmit QoS rules to UE, etc.

[0085] N2 interface is the interface between AMF and RAN, which is used to transmit radio bearer control information, etc.

[0086] N3 interface is the interface between UPF and RAN, which is used to transmit uplink and downlink data of UE.

[0087] N4 interface is the interface between SMF and UPF, which is used to transmit information between control plane and user plane, including control plane sending QoS rules, traffic rules, network status information reporting, etc.

[0088] N6 interface is the interface between UPF and DN, which is used to transmit uplink and downlink data between UPF and DN.

[0089] Nnssf, Nnef, Nnrf, Npcf, Nudm, Naf, Nausf, Namf and Nsmf are service interfaces provided by NSSF, NEF, NRF, PCF, UDM, AF, AUSF, AMF and SMF, respectively, which can be invoked to enable the corresponding functions to service the operations accordingly.

[0090] (1) Based on the typical architecture of the above communication system, embodiments of the present application propose an architecture of a future communication system based on the typical architecture:

[0091] As shown in FIG. 2, the future communication system includes a terminal device (UE), an access network device (such as RAN), a mobility management function (such as AMF), a service session management function (such as serving session management function, S-SMF), a service user plane function (such as serving user plane function, S-UPF), and a session management function (such as SMF) in a network domain (such as Network), a user plane function (such as UPF), and a DN, etc. In the future communication system, different types of network domains can be divided according to different services provided or different ranges of services provided. Optionally, the type of network domain can be a user home network (or called home network), a private network such as a local area network (or called local network), a subnetwork (or called subnetwork), an open network provided by a service provider (or called public network), a special network deployed (or called special network), etc. The UE, access network device and DN can refer to the corresponding description in FIG. 1. The mobility management function can be used to perform the functions of the AMF in FIG. 1, and is also used to select a suitable S-SMF for the terminal device. The functions of the remaining functions are as follows:

[0092] S-SMF: a session management function for managing one or more sessions of a UE, connected with the AMF and the SMF in the network domain, and deployed closer to the UE than the SMF. Optionally, one S-SMF can be connected with the SMFs in multiple network domains, thereby managing the sessions in multiple network domains. In embodiments of the present application, when managing the sessions of the UE, the S-SMF can select the S-UPF and the SMF in the network domain, and trigger the establishment, modification and release of the session resources (hereinafter referred to as the establishment, modification and release of the session), including one or more of the session QoS, the session path and the routing rule. The S-SMF triggering the establishment, modification and release of the session includes triggering the S-UPF to establish, modify and release the session, and triggering the SMF to establish, modify and release the session.

[0093] S-UPF: performs packet routing and transmission according to the routing rules issued by the S-SMF. In the present application, the S-UPF can be responsible for receiving uplink packets from the access network device and sending the uplink packets to the UPF in the corresponding network domain, and correspondingly, the S-UPF is responsible for receiving downlink packets from the UPF and sending the downlink packets to the access network device.

[0094] SMF in the network domain: responsible for the selection of the UPF in the corresponding network domain, and connected with the S-SMF to respond to the session management of the S-SMF, perform operations such as corresponding allocation, modification and release of the session, etc.

[0095] UPF in the network domain: performs packet routing and transmission according to the routing rules issued by the SMF in the corresponding network domain. In the embodiments of the present application, the UPF in the network domain can be responsible for receiving uplink packets from the S-UPF and sending the uplink packets to the DN in the corresponding network domain, and correspondingly, the UPF in the network domain is responsible for receiving downlink packets from the DN in the corresponding network domain and sending the downlink packets to the S-UPF.

[0096] For example, the interface between the UPF and the S-UPF for transmitting uplink and downlink data is the N9 interface, and the interface between the RAN and the S-UPF for transmitting uplink and downlink data is the N3 interface.

[0097] It should be noted that FIG. 2 can also include the functions of NSSF, NEF, NRF, PCF, UDM, AF and AUSF shown in FIG. 1, or, and / or, can also include more functions not shown, which are not limited by the present application.

[0098] (2) Based on the future communication system shown in FIG. 2, the embodiments of the present application further propose an architecture of a communication system integrated with a 4G communication system on the basis of the future communication system:

[0099] As shown in FIG. 3, the integrated communication system includes UE, evolved universal terrestrial radio access network (E-UTRAN), next generation radio access network (NG-RAN), MME, AMF, SGW-C+S-SMF, SGW-U+S-UPF, PGW-C+SMF, PGW-U+UPF, PCF, HSS+UDM, etc.

[0100] Wherein, the E-UTRAN is a RAN in the 4G communication system, and the NG-RAN is an exemplary RAN in the future communication system. It can be understood that the RAN in the future communication system can also be other RANs or other names, which are not limited in the present application.

[0101] The MME is a function in the 4G communication system responsible for access management, mobility management, reachability management, access authentication and authorization, etc. of the UE.

[0102] The SGW-C+S-SMF is a function after the S-SMF in FIG. 2 is combined with the SGW-C in the 4G communication system. The SGW-C+S-SMF is used to perform the functions similar to the S-SMF in FIG. 2, including selecting the SGW-U+S-UPF, managing the session of the UE in the 4G communication network and the session in the future communication network (such as triggering to establish, modify and release the session).

[0103] The SGW-U+S-UPF is a function after the S-UPF in FIG. 2 is combined with the SGW-U in the 4G communication system. The SGW-U+S-UPF is used to perform the functions similar to the S-UPF in FIG. 2, including performing the packet routing and transmission according to the routing rules issued by the SGW-C+S-SMF.

[0104] The PGW-C+SMF is a function after the SMF in FIG. 2 is combined with the PGW-C in the 4G communication system. The PGW-C+SMF is used to perform the functions similar to the SMF in FIG. 2, including selecting the PGW-U+UPF and performing the operations of allocating, modifying and releasing the session accordingly in response to the session management of the SGW-C+S-SMF, etc.

[0105] The PGW-U+UPF is a function after the UPF in FIG. 2 is combined with the PGW-U in the 4G communication system. The PGW-U+UPF is used to perform the functions similar to the UPF in FIG. 2, including performing the packet routing and transmission according to the routing rules issued by the PGW-C+SMF.

[0106] The HSS+UDM is a function after the UDM in FIG. 1 is combined with the home subscriber server (HSS) in the 4G communication system. The HSS+UDM is used to perform the functions similar to the UDM in FIG. 1, including user subscription context management, etc.

[0107] For example, the interface between the E-UTRAN and the SGW-U+S-UPF for transmitting uplink and downlink data is an S1-U interface, the interface between the NG-RAN and the SGW-U+S-UPF for transmitting uplink and downlink data is an N3 interface, the interface between the SGW-U+S-UPF and the PGW-U+UPF for transmitting uplink and downlink data is an S5 interface, and the interface between the SGW-U+S-UPF and the PGW-U+UPF for transmitting uplink and downlink data is an N9 interface.

[0108] It should be noted that FIG. 3 can also include the NSSF, NEF, NRF, PCF, UDM, AF, and AUSF functions shown in FIG. 1, or can also include more functions not shown, and the present application does not limit this.

[0109] In addition, the architectures of FIGS. 2 and 3 are only exemplary, and the network architecture to which the embodiments of the present application are applicable is not limited thereto. Any network architecture that can implement the above-mentioned functions is applicable to the embodiments of the present application, and the above-mentioned functions can also have other names in other network architectures, and the embodiments of the present application do not limit this. It can be understood that the technical solutions provided by the present application can also be applied to device to device (D2D) communication, vehicle-to-everything (V2X) communication, machine to machine (M2M) communication, machine type communication (MTC), and internet of things (IoT) communication systems or other communication systems.

[0110] The technical problems related to the embodiments of the present application are introduced as follows:

[0111] A session is used to associate a UE and a DN, and is a logical connection established for data exchange between the UE and the DN, and supports transmission of uplink and downlink data of various service types, such as voice, video, and audio type data, and QoS management of data of different service types or different users. The session in the 4G communication system is referred to as an evolved packet system (EPS) session, and the session in the 5G communication system is referred to as a protocol data unit (PDU) session.

[0112] Currently, in the existing mobility management procedure, the update of the session of the UE is triggered, and the granularity of the session update is the session level. That is to say, if the UE has multiple sessions, in the mobility management procedure, the update of the sessions of the UE needs to be triggered one by one. That is, it is usually necessary to request the function of managing the corresponding session to obtain the context of the session one by one, and the context of different sessions is received one by one to update different sessions.

[0113] For example, taking the 5G communication system as an example, when the UE moves out of the service range of the SMF, an I-SMF can be inserted between the AMF and the SMF, and an I-UPF can be inserted between the RAN and the UPF; when the UE moves out of the service range of the I-SMF, the switching of the RAN, the I-SMF and the I-UPF can be involved, and then the target I-SMF needs to send a corresponding request message for each session of the UE to the source I-SMF to obtain the context of the corresponding session, and then the target I-SMF can update the session based on the context of the corresponding session. When the number of sessions of the UE is large, the target I-SMF needs to send a request message to the source I-SMF multiple times, and correspondingly, the source I-SMF needs to return the context of the session corresponding to the request message to the target I-SMF multiple times.

[0114] Or, when the UE moves between the service area of the 4G communication network and the service area of the 5G communication network, taking the movement from the service area of the 5G communication network to the service area of the 4G communication network as an example, the AMF sends a request message for each session of the UE to the SMF one by one to obtain the context of the session corresponding to each request message from the SMF, and then the AMF sends the context of the session corresponding to each request message to the MME, so that the MME can update the session corresponding to each request message. When the number of sessions of the UE is large, the AMF needs to send a request message to the SMF multiple times, and the SMF needs to return the context of the session corresponding to the request message to the AMF multiple times.

[0115] As can be seen, in the existing mobility management procedure, the session update needs to transmit a large amount of signaling, which not only causes large signaling overhead, but also causes long switching delay of the UE.

[0116] In order to effectively reduce the signaling overhead and reduce the switching delay of the terminal device, the communication system shown in FIGS. 2 and 3 is provided, and a communication method based on the communication system of FIGS. 2 and 3 is provided. When multiple sessions of a terminal device are updated, the context of the multiple sessions is obtained through one request, and the multiple sessions are updated, thereby effectively reducing the signaling overhead.

[0117] The application scenario of the embodiments of the present application will be introduced first as follows:

[0118] Based on the future communication system shown in FIG. 2, when the terminal device moves across the service area of the access gateway (such as including the service session management function and the service user plane function), the IP anchor point of the terminal device (such as including the session management function in the network domain, the user plane function, and the DN) does not change, and the access gateway of the terminal device needs to be switched, and the session of the terminal device needs to be updated. Optionally, when the terminal device moves, the mobility management function can change or not change, and the embodiments of the present application do not limit this, and the following embodiments are described by taking the case that the mobility management function changes as an example.

[0119] Alternatively, based on the converged communication system shown in FIG. 3, when the terminal device moves between the service area of the 4G communication network and the service area of the future communication network, the IP anchor point of the terminal device (such as including the PGW-C+SMF and the PGW-U+UPF) does not change, the access gateway of the network connected by the terminal device (such as including the E-UTRAN, the MME, the SGW-C+S-SMF, and the SGW-U+S-UPF; or, including the AMF, the NG-RAN, the SGW-C+S-SMF, and the SGW-U+S-UPF) needs to be switched, and the session of the terminal device needs to be updated.

[0120] Suppose that the terminal device has multiple sessions, then for the two application scenarios, FIG. 4 shows a flowchart of a communication method provided by an embodiment of the present application, wherein the communication method includes steps 401 to 405. Among them, the first mobility management function and the first service session management function provide services for the terminal device before the terminal device moves, the second service session management function provides services for the terminal device after the terminal device moves, and the service session management function is used to manage multiple sessions of the terminal device.

[0121] In specific implementation, the communication system applied by FIG. 4 can be the future communication system shown in FIG. 2, that is, the service session management function is the S-SMF in FIG. 2. Alternatively, the communication system applied by FIG. 4 can be the converged communication system shown in FIG. 3, that is, the service session management function is the SGW-C+S-SMF in FIG. 3. For example, the S-SMF can be an I-SMF or an L-SMF, and the I-SMF or the L-SMF supports managing multiple sessions of the terminal device. Specifically:

[0122] 401、The first mobility management function selects the first service session management function based on the first location information.

[0123] In the embodiments of the present application, when the terminal device moves, the first mobility management function that can provide services for the terminal device after the terminal device moves can be determined first, and the manner of determining the first mobility management function can refer to the embodiments shown in FIG. 6 / FIG. 8 / FIG. 10 described below; then, the first mobility management function selects the first service session management function based on the first location information. The first location information is used to indicate the location of the terminal device.

[0124] In a possible implementation, the first location information includes the location information of the terminal device. For example, the location information of the terminal device can include the latitude and longitude coordinates of the terminal device. In this way, the first location information can indicate the accurate location of the terminal device, and the first mobility management function can select the first service session management function based on the accurate location of the terminal device.

[0125] In another possible implementation, the first location information includes the location information of the access network device that can provide services for the terminal device after the terminal device moves, or the first location information includes the identification information of the coverage area of the access network device. For example, the first location information includes the identification (NodeID, eNBID) of the access network device, or the first location information includes one or more of the tracing area identification (tracing area ID, TAI), the location area identification (location area ID, LAI), or the global cell identifier (cell global identifier, CGI). In this way, the first location information can indicate the approximate location of the terminal device, and the first mobility management function can select the first service session management function based on the approximate location of the terminal device.

[0126] It can be understood that the first location information can also include a combination of multiple information in the above examples, and the embodiments of the present application do not limit this.

[0127] 402、The first mobility management function sends a first message to the first service session management function, and the first message is used to request switching the terminal device from the second service session management function to the first service session management function. Correspondingly, the first service session management function receives the first message.

[0128] In a possible implementation, the first message includes the context identification of multiple sessions of the terminal device and the first location information. The context identification of multiple sessions of the terminal device is used to indicate multiple sessions of the terminal device on the second service session management function, or it can be understood that the context identification is used to indicate multiple sessions of the terminal device managed by the second service session management function.

[0129] In a possible implementation, the context identifier includes information of the second service session management function and identification information for indicating the multiple sessions of the terminal device, and the information of the second service session management function is used to indicate the second service session management function. For example, the information of the second service session management function includes one or more of an instance identifier, an internet protocol (IP) address, or a fully qualified domain name (FQDN) of the second service session management function, but is not limited to these.

[0130] Optionally, the identification information for indicating the multiple sessions can include identification information of the terminal device, that is, the multiple sessions of the terminal device are indicated based on the identification information of the terminal device. For example, the identification information of the terminal device includes one or more of an international mobile subscriber identity (IMSI), a subscription permanent identifier (SUPI), a subscription concealed identifier (SUCI), or a globally unique temporary identity (GUTI), but is not limited to these.

[0131] Optionally, the identification information for indicating the multiple sessions of the terminal device can include session identifiers of the multiple sessions, that is, the multiple sessions are indicated based on the session identifiers of the multiple sessions. For example, the session identifier includes one or more of a PDU session ID or an EPS bearer identity (EBI), but is not limited to these.

[0132] Optionally, the identification information for indicating the multiple sessions of the terminal device can include session context identifiers of the multiple sessions, that is, the multiple sessions are indicated based on the session context identifiers of the multiple sessions. For example, the session context identifier of the session includes one or more of an identification of the session in the second service session management function, such as a session management context reference (smContextRef) or a session management context ID, but is not limited to these.

[0133] Optionally, the identification information for indicating the multiple sessions of the terminal device can comprise tunnel endpoint identifiers (TEIDs) corresponding to the multiple sessions, i.e., the multiple sessions of the terminal device are indicated based on the TEIDs corresponding to the multiple sessions. One session can correspond to one TEID or multiple TEIDs, or different sessions can correspond to the same TEID, which is not limited in the embodiments of the present application.

[0134] Optionally, the identification information for indicating the multiple sessions of the terminal device can comprise PDN connection identifiers corresponding to the multiple sessions. The PDN connection identifier refers to an identifier of a PDN connection between the terminal device and a data network, and one session corresponds to one or more PDN connection identifiers. The PDN connection identifier can be used to associate the terminal device with the data network accessed thereby, so that the terminal device can identify the session corresponding to the PDN connection identifier when switching between different communication networks (such as switching between a 4G communication network and a future communication network).

[0135] It can be understood that the identification information for indicating the multiple sessions of the terminal device can also comprise a combination of the multiple types of identification information in the above examples. The identification information for indicating the multiple sessions is only an example and is not limited thereto.

[0136] 403. The first service session management function sends a second message to the second service session management function, the second message being used to acquire contexts of the multiple sessions of the terminal device. Correspondingly, the second service session management function receives the second message.

[0137] In a possible implementation, the second message comprises the context identifier. The first service session management function can request the contexts of the multiple sessions of the terminal device from the second service session management function by carrying the context identifier, so as to update the multiple sessions.

[0138] The existing mobility management procedure is performed in a session granularity, i.e., the context of one session of the terminal device managed by the second service session management function is requested and updated each time. If the second service session management function manages multiple sessions of the terminal device, the procedure needs to be performed multiple times, i.e., the request message is sent to the second service session management function multiple times for the multiple sessions. The implementation of the present application requests the contexts of the multiple sessions of the terminal device through the second message, thereby reducing the number of signaling interactions, so as to effectively reduce the signaling overhead, improve the processing efficiency of the second service session management function, and reduce the switching delay of the terminal device.

[0139] 404、The second service session management function sends a third message to the first service session management function, and the third message includes the contexts of the multiple sessions of the terminal device. Accordingly, the first service session management function receives the third message.

[0140] According to the context identifier in the received second message, the second service session management function accurately confirms the contexts of the multiple sessions of the terminal device, and returns the contexts of the multiple sessions to the first service session management function through the third message.

[0141] The existing mobility management procedure is performed in a session granularity, that is, after the second service session management function receives a request for obtaining the context of one session each time, the second service session management function returns the context of the one session to update the one session. If the second service session management function manages multiple sessions of the terminal device, the procedure needs to be performed multiple times, that is, for multiple sessions, the second service session management function returns the contexts of different sessions multiple times. However, the implementation manner returns the contexts of the multiple sessions of the terminal device through the third message, reduces the number of signaling interactions, and thus can reduce signaling overhead, improve the processing efficiency of the second service session management function, and reduce the switching delay of the terminal device.

[0142] The context of each session in the multiple sessions includes but is not limited to one or more of the following: an identifier of the session, information of a session management function corresponding to the session, an identifier of the session in the corresponding session management function, user plane tunnel information corresponding to the session, or QoS information corresponding to the session.

[0143] The identifier of the session can be the session identifier introduced in step 402, the information of the session management function corresponding to the session can refer to the information of the second service session management function, the identifier of the session in the corresponding session management function can refer to the context identifier of the session introduced in step 402, and the QoS information corresponding to the session includes but is not limited to a QoS flow identity (QFI) and QoS flow description information.

[0144] The user plane tunnel information corresponding to the session is introduced as follows:

[0145] Taking the communication system shown in FIG. 2 as an example, the user plane tunnel information corresponding to the session includes information of a tunnel of an N9 interface of a UPF in a network domain corresponding to the session (hereinafter referred to as N9 tunnel information); taking the 4G communication network under the communication system shown in FIG. 3 as an example, the user plane tunnel information corresponding to the session includes N9 tunnel information of a PGW-U+UPF in a future communication network corresponding to the session; taking the future communication network under the communication system shown in FIG. 3 as an example, the user plane tunnel information corresponding to the session includes information of a tunnel of an S5 interface of a PGW-U+UPF in a 4G communication network corresponding to the session (hereinafter referred to as S5 tunnel information); for example, the tunnel information can be an endpoint identifier or a tunnel address of the tunnel.

[0146] 405、The first service session management function updates the plurality of sessions based on the context of the plurality of sessions.

[0147] In a possible implementation, the first service session management function updates the plurality of sessions based on the context of the plurality of sessions, including re-establishing user plane tunnels of the plurality of sessions. Specifically, the first service session management function selects a first service user plane function based on the first location information; sends tunnel information of a user plane function corresponding to the plurality of sessions to the first service user plane function; and sends tunnel information of the first service user plane function to a session management function corresponding to the plurality of sessions.

[0148] The service user plane function is a user plane function that performs data packet routing and transmission for the plurality of sessions of the terminal device (for example, S-UPF in FIG. 2, or SGW-U+S-UPF in FIG. 3). The first service user plane function is a service user plane function that can provide services for the terminal device after the terminal device moves. The first service session management function can select the first service user plane function based on the first location information. Then, the first service session management function can trigger establishment of a tunnel between a user plane function corresponding to the plurality of sessions and the first service user plane function.

[0149] Specifically, the first service session management function sends the tunnel information of the user plane functions corresponding to the multiple sessions to the first service user plane function, so that the first service user plane function receives the tunnel information of the user plane functions corresponding to the multiple sessions. At the same time, the first service session management function sends the tunnel information of the first service user plane function to the multiple session corresponding session management functions, so that the multiple session corresponding session management functions can send the tunnel information of the first service user plane function to the multiple session corresponding user plane functions, and then the multiple session corresponding user plane functions receive the tunnel information of the first service user plane function. In this way, the first service user plane function establishes a tunnel between the multiple session corresponding user plane functions and the first service user plane function based on the received tunnel information of the multiple session corresponding user plane functions, and the multiple session corresponding user plane functions establish a tunnel between the multiple session corresponding user plane functions and the first service user plane function based on the received tunnel information of the first service user plane function, thereby ensuring data transmission of the terminal device.

[0150] The multiple session corresponding user plane functions refer to the user plane functions in the multiple session corresponding network domains, and the multiple session corresponding session management functions refer to the session management functions in the multiple session corresponding network domains. For example, in the communication system shown in FIG. 2, the multiple session corresponding session management functions and user plane functions refer to SMFs and UPFs in the multiple session corresponding network domains. In the communication system shown in FIG. 3, the SMFs in the multiple session corresponding network domains are also combined with corresponding PGW-Cs (i.e., PGW-C+SMF), and the UPFs in the multiple session corresponding network domains are also combined with corresponding PGW-Us (i.e., PGW-U+UPF).

[0151] Optionally, when the service session management function supports managing sessions in different network domains, the types of the multiple session corresponding network domains can be the same or different. For example, the type of a session corresponding network domain is a home network, a private network, a public network, or a local network.

[0152] Correspondingly, in the communication system shown in FIG. 2, a session corresponding session management function can be an SMF in a home network, a private network, a public network, or a local network, and a session corresponding user plane function can be a UPF in a home network, a private network, a public network, or a local network. The SMF in the home network can also be referred to as an A-SMF, the SMF in the private network can also be referred to as a private network SMF, the SMF in the public network can also be referred to as a public network SMF, and the SMF in the local network can also be referred to as an L-SMF. The UPF in the home network can also be referred to as a PSA, the UPF in the private network can also be referred to as a private network UPF, the UPF in the public network can also be referred to as a public network UPF, and the UPF in the local network can also be referred to as an L-UPF.

[0153] Correspondingly, in the communication system shown in FIG. 3, the session management function corresponding to one session can be a PGW-C+SMF in a home network, a private network, a public network or a local network, and the user plane function corresponding to one session can be a PGW-U+UPF in the home network, the private network, the public network or the local network. The PGW-C+SMF in the home network can also be referred to as a PGW-C+A-SMF, the PGW-C+SMF in the private network can also be referred to as a PGW-C+private network SMF, the PGW-C+SMF in the public network can also be referred to as a PGW-C+public network SMF, and the PGW-C+SMF in the local network can also be referred to as a PGW-C+L-SMF. The PGW-U+UPF in the home network can also be referred to as a PGW-U+PSA, the PGW-U+UPF in the private network can also be referred to as a PGW-U+private network UPF, the PGW-U+UPF in the public network can also be referred to as a PGW-U+public network UPF, and the PGW-U+UPF in the local network can also be referred to as a PGW-U+L-UPF.

[0154] If the multiple sessions are sessions in different network domains, the session management functions and the user plane functions corresponding to the sessions in the different network domains are session management functions and user plane functions in the different network domains. For example, the session management functions corresponding to the multiple sessions include a first session management function and a second session management function, the first session management function and the second session management function are session management functions in different network domains, the user plane function managed by the first session management function is a first user plane function, the user plane function managed by the second session management function is a second user plane function, and the first service user plane function can assign different service user plane function tunnel information (for example, the tunnel information is N9 tunnel information or S5 tunnel information) to different sessions, such as assigning first tunnel information and second tunnel information.

[0155] Optionally, the different network domains herein can refer to different types of network domains, such as a home network and a public network, or can refer to different network domains under the same type of network domain, such as a public network 1 and a public network 2, and the like. The embodiments of the present application do not limit this.

[0156] The above sending, to the session management functions corresponding to the multiple sessions, the first service user plane function tunnel information includes sending, to the first session management function, first tunnel information of the first service user plane function and sending, to the second session management function, second tunnel information of the first service user plane function. Further, the first session management function sends the first tunnel information to the first user plane function, and the second session management function sends the second tunnel information to the second user plane function. The above sending, to the first service user plane function, the tunnel information of the user plane functions corresponding to the multiple sessions includes sending, to the first service user plane function, tunnel information of the first user plane function and tunnel information of the second user plane function.

[0157] In this way, a tunnel (for example, an N9 tunnel or an S5 tunnel) between the first service user plane function and the first user plane function can be established based on the first tunnel information of the first service user plane function and the tunnel information of the first user plane function, and a tunnel (for example, an N9 tunnel or an S5 tunnel) between the first service user plane function and the second user plane function can be established based on the second tunnel information of the first service user plane function and the tunnel information of the second user plane function. In this way, the isolation between multiple sessions in different network domains can be achieved, thereby ensuring the security of each session.

[0158] It can be understood that the first service session management function can also trigger the establishment of a tunnel between the first service user plane function and the access network device. For example, the first service session management function sends N3 tunnel information or S1-U tunnel information of the first service user plane function to the first mobility management function, and the first service session management function also needs to send N3 tunnel information or S1-U tunnel information of the access network device to the first service user plane function.

[0159] Based on the above, the user plane tunnels between the access network device and the first service user plane function, and the user plane functions in the network domains corresponding to the multiple sessions can be established, thereby achieving the update of the multiple sessions.

[0160] Based on the embodiment described in FIG. 4, when the terminal device moves, the first service session management function can request the context of the multiple sessions of the terminal device by sending a second message to the second service session management function, and the second service session management function can return the context of the multiple sessions of the terminal device by sending a third message to the first service session management function. Compared with the existing mobility management process, the number of signaling interactions is reduced, thereby effectively reducing the signaling overhead, improving the processing efficiency of the second service session management function, and reducing the handover delay of the terminal device.

[0161] The following will take the communication system shown in FIG. 2 as an example to introduce the interaction process described in FIG. 4 in detail:

[0162] Based on the future communication system shown in FIG. 2, FIG. 5 shows the function switching involved when the UE moves. In the embodiment corresponding to FIG. 4, the first service session management function, the second service session management function, the first mobility management function, the first service user plane function, the session management functions corresponding to the multiple sessions, and the user plane functions corresponding to the multiple sessions are the first S-SMF, the second S-SMF, the first AMF, the first S-UPF, the SMF in the network domain, and the UPF in the network domain in FIG. 5, respectively.

[0163] Before moving, the UE performs uplink and downlink data transmission with the DN via the second RAN, the second S-UPF and the UPF in the network domain; the second S-UPF is managed by the second S-SMF, and the UPF in the network domain is managed by the SMF in the network domain, and the SMF and the UPF in the network domain are taken as the A-SMF and the PSA for description below. When the UE moves from the service area of the second RAN, the second AMF, the second S-SMF and the second S-UPF to the service area of the first RAN, the first AMF, the first S-SMF and the first S-UPF, the second RAN, the second AMF, the second S-SMF and the second S-UPF need to be switched to the first RAN, the first AMF, the first S-SMF and the first S-UPF respectively. After switching, the UE performs uplink and downlink data transmission with the DN via the first RAN, the first S-UPF and the UPF in the network domain, and the first S-UPF is managed by the first S-SMF.

[0164] Specifically, the interaction process involved in the process can be seen from the flowchart corresponding to FIG. 6, including steps 600 to 621, wherein:

[0165] 600, the UE establishes multiple sessions through the second S-SMF.

[0166] The multiple sessions (such as PDU sessions) established by the UE through the second S-SMF are served by the second RAN, the second S-UPF and the PSA.

[0167] In a possible implementation, the multiple sessions include a first session and a second session, and the PSA corresponding to the first session and the PSA corresponding to the second session can be the same or different.

[0168] 601, the second RAN sends a first handover request message to the second AMF.

[0169] When the UE gradually moves out of the service area of the second RAN and the second AMF, the second RAN sends a first handover request (for example, handover required) message to the second AMF. The first handover request message is used to request the target side to prepare resources, and the first handover request message includes the first location information in the above-mentioned embodiment corresponding to FIG. 4, for example, the first location information can include but is not limited to one or more of the location information of the UE, the location information of the first RAN or the identification information of the coverage area in the first RAN. For example, the first location information includes one or more of the latitude and longitude coordinates of the UE, the eNBID of the first RAN or the TAI of the first RAN, etc.

[0170] 602, the second AMF sends a UE context creation request message to the first AMF.

[0171] The second AMF can first select an AMF (i.e., the first AMF) capable of providing services for the UE according to the first location information, and then send, to the first AMF, a UE context creation request (e.g., Namf_communication_createUEcontext request) message for requesting the first AMF to create a UE context, wherein the UE context creation request message includes the context identifier of the multiple sessions of the UE and the first location information. The context identifier of the multiple sessions of the UE can include information (such as one or more of an instance identifier, an IP address, or an FQDN of the second S-SMF) of the second S-SMF and identification information (such as one or more of the identification information of the UE, a PDU session ID of each session, an SM context reference of each session, or a TEID of each session) for indicating the multiple sessions of the terminal device.

[0172] 603. The first AMF sends a first message to the first S-SMF.

[0173] For example, the first message is a PDU session context creation request (e.g., Nsmf_PDUsession_createSMcontext request) message. The first AMF can first select an S-SMF (i.e., the first S-SMF) capable of providing services for the UE according to the first location information carried in the received UE context creation request message, and then send, to the first S-SMF, the first message for requesting the first S-SMF to create a session context. The session context can be multiple, corresponding to the multiple sessions in step 600, and the first message carries the context identifier of the session and the first location information.

[0174] 604. The first S-SMF sends a second message to the second S-SMF.

[0175] For example, the second message is a PDU session context request (e.g., Nsmf_PDUsession_context request) message or a retrieve SM context request message. The first S-SMF sends, to the second S-SMF, the second message for requesting the context of the multiple sessions of the UE through the context identifier (such as the information of the second S-SMF and the identification information for indicating the multiple sessions of the terminal device) in the received first message, wherein the second message carries the context identifier. The context identifier can refer to the description in step 602 or the description in the corresponding embodiment of the above FIG. 4.

[0176] 605. The second S-SMF sends a third message to the first S-SMF.

[0177] For example, the third message is a PDU session context response (e.g., Nsmf_PDUsession_context response) message or a retrieve SM context request response (e.g., retrieve SM context response) message, etc. The second S-SMF can confirm the contexts of the multiple sessions of the UE according to the context identifier in the received second message. Then the second S-SMF sends a third message to the first S-SMF, and the third message carries the contexts of the multiple sessions, for example, the contexts of the multiple sessions include the N9 tunnel information of the PSA corresponding to each session in the multiple sessions.

[0178] Optionally, the contexts of the multiple sessions can further include one or more of the following: identification information of each session in the multiple sessions, information of the A-SMF corresponding to each session, an identifier of each session in the corresponding A-SMF, or QoS information corresponding to each session, etc. It should be noted that the A-SMFs corresponding to different sessions can be the same or different, and the embodiments of the present application do not limit this.

[0179] Optionally, after step 605, the second S-SMF can first obtain the user subscription data of the UE, and the user subscription data includes session policies (such as home network policies, local network policies, etc.), such as quality of service (QoS), security measures, charging rules, and other important parameters. If the second S-SMF identifies that the UE after moving satisfies the session policy corresponding to the established session, the subsequent steps can be executed to update the established session; if the established session corresponding to the session policy is not satisfied, for example, the first session is a session in the local network, and the UE moves out of the coverage range of the local network, that is, the location of the UE exceeds the service area indicated by the session policy of the first session, then the first session can be released, and the present application does not repeat the way of releasing the session.

[0180] 606、The first S-SMF performs a packet forwarding protocol session establishment with the first S-UPF.

[0181] The first S-SMF selects an S-UPF capable of providing services for the UE, i.e., a first S-UPF, according to the first location information. Then, the first S-SMF sends a packet forwarding control protocol (PFCP) session establishment request message to the first S-UPF, where the PFCP session establishment request message is used to establish a PFCP session. The PFCP session establishment request message carries tunnel information corresponding to each session of the multiple sessions. For example, the PFCP session establishment request message includes N9 tunnel information of a PSA corresponding to a first session and N9 tunnel information of a PSA corresponding to a second session, where the N9 tunnel information of the PSA corresponding to the first session and the N9 tunnel information of the PSA corresponding to the second session are obtained from the context of the multiple sessions received in step 605. The PFCP session establishment request message is also used to request the first S-UPF to allocate N3 tunnel information and N9 tunnel information.

[0182] Optionally, if the multiple sessions include sessions in different network domains, the PFCP session establishment request message is also used to request the first S-UPF to allocate different N9 tunnel information of the first S-UPF for the sessions in different network domains.

[0183] For example, the first session and the second session are sessions in two different home networks, respectively, the PSA corresponding to the first session is PSA1, and the PSA corresponding to the second session is PSA2. The first S-UPF can be requested to allocate N9 tunnel information (i.e., first tunnel information and second tunnel information) of the first S-UPF corresponding to PSA1 and PSA2, respectively. The N9 tunnel information of the first S-UPF corresponding to PSA1 is different from the N9 tunnel information of the first S-UPF corresponding to PSA2.

[0184] It can be understood that the embodiments of the present application are described by taking a home network as an example. When the types of network domains to which different sessions belong are different, the corresponding N9 tunnel information of the first S-UPF can also be allocated in a similar manner.

[0185] 607. The first S-SMF sends a response message of the first message to the first AMF.

[0186] For example, the response message of the first message is a PDU session context creation response (e.g., Nsmf_PDUsession_createSMcontext response) message, etc., which is used to indicate that the first S-SMF successfully creates a session context, and the response message of the first message carries tunnel information allocated by the first S-UPF, such as N3 tunnel information of the first S-UPF.

[0187] 608. The first AMF sends a second handover request message to the first RAN.

[0188] The first AMF determines the first RAN according to the first location information carried in the UE context creation request message received in step 602. Then, the first AMF sends a second handover request message to the first RAN, the second handover request message is used to request the first RAN to prepare resources (e.g., request the first RAN to allocate N3 tunnel information), and the second handover request message carries the tunnel information allocated by the first S-UPF, for example, carries the N3 tunnel information of the first S-UPF.

[0189] 609、The first RAN sends an acknowledgement message of the second handover request message to the first AMF.

[0190] The first RAN allocates the N3 tunnel information of the first RAN in response to the received second handover request message, and then sends an acknowledgement (e.g., handover request acknowledge) message of the second handover request message to the first AMF, the acknowledgement message of the second handover request message carries the tunnel information allocated by the first RAN, for example, carries the N3 tunnel information of the first RAN.

[0191] 610、The first AMF sends a session context update request message to the first S-SMF.

[0192] The first AMF sends a session context update request (e.g., Nsmf_PDUsession_updateSMcontext request) message to the first S-SMF, the session context update request message carries the N3 tunnel information allocated by the first RAN, for example, carries the N3 tunnel information of the first RAN.

[0193] 611、The first S-SMF sends a session context update response message to the first AMF.

[0194] The first S-SMF sends a session context update response (e.g., Nsmf_PDUsession_updateSMcontext response) message to the first AMF.

[0195] 612、The first AMF sends a UE context creation response message to the second AMF.

[0196] The first AMF sends a UE context creation response (e.g., Namf_communication_createUEcontext response) message to the second AMF, the UE context creation response message is the response message of the UE context creation request message in step 602.

[0197] 613、The second AMF sends a first handover instruction to the second RAN.

[0198] The second AMF sends a first handover instruction (e.g., handover command) to the second RAN, the first handover instruction being used to inform the second RAN that the first RAN has prepared the resources needed for the handover.

[0199] 614. The second RAN sends a second handover instruction to the UE.

[0200] The second RAN sends a second handover instruction (e.g., handover command, etc.) to the UE, the second handover instruction being used to instruct the UE to handover from the second RAN to the first RAN.

[0201] 615. The UE sends a handover confirmation message to the first RAN.

[0202] After the UE hands over to the first RAN, the UE sends a handover confirmation (e.g., handover confirm) message to the first RAN, the handover confirmation message being used to indicate that the UE has handed over from the second RAN to the first RAN, i.e., the handover is completed.

[0203] 616. The first RAN sends a handover notification message to the first AMF.

[0204] The first RAN sends a handover notification (e.g., handover notify) message to the first AMF, the handover notification message being used to indicate that the handover is completed.

[0205] 617. The first AMF notifies the first S-SMF that the handover is completed.

[0206] For example, the first AMF sends a Namf_communication_N2Info notify message to the first S-SMF, the Namf_communication_N2Info notify message being used to indicate that the handover is completed.

[0207] 618. The first S-SMF performs a packet forwarding protocol session modification with the first S-UPF.

[0208] The first S-SMF sends a PFCP session modification request message to the first S-UPF, the PFCP session modification request message carrying the N3 tunnel information of the first RAN in step 610, so that the first S-UPF establishes an N3 tunnel between the first RAN and the first S-UPF based on the received N3 tunnel information of the first RAN, and the first RAN establishes an N3 tunnel between the first RAN and the first S-UPF based on the received N3 tunnel information of the first S-UPF in step 608.

[0209] 619. The first S-SMF sends a session update request message to the A-SMF.

[0210] The first S-SMF sends a session update request (e.g., Nsmf_PDUsession_update request) message to the A-SMF. Taking the first session as an example, the first S-SMF first confirms the A-SMF serving the first session according to the context of the first session received in step 605 (e.g., A-SMF information corresponding to the first session); and then sends a session update request message to the A-SMF, where the session update request message carries the N9 tunnel information of the first S-UPF, and the session update request message is used to request to establish and update the first session, and is used to request to update the N9 tunnel of the first S-UPF to the PSA corresponding to the first session.

[0211] 620. The A-SMF performs a packet forwarding control protocol session modification with the PSA.

[0212] The A-SMF sends a PFCP session modification request message to the PSA. Taking the first session as an example, the PFCP session modification request message carries the N9 tunnel information of the first S-UPF in step 619, so that the PSA corresponding to the first session establishes the N9 tunnel of the first S-UPF based on the received N9 tunnel information of the first S-UPF and the N9 tunnel information of the PSA corresponding to the first session received by the first S-UPF in step 606.

[0213] 621. The A-SMF sends a session update response message to the first S-SMF.

[0214] The A-SMF sends a session update response (e.g., Nsmf_PDUsession_update response) message to the first S-SMF, where the session update response message is a response message of the session update request message in step 619, and the session update response message is used to indicate that the session update is successful, e.g., the first session update is successful.

[0215] The steps 606 and 621 above are detailed implementation manners of step 405 in the embodiment of FIG. 4.

[0216] Optionally, if the terminal device establishes the first session and the second session in step 600, the steps 619-621 can be performed once for the first session, and the steps 619-621 can also be performed once for the second session, e.g., the first S-SMF can also send the N9 tunnel information of the first S-UPF to the A-SMF corresponding to the second session, the A-SMF corresponding to the second session can send the N9 tunnel information of the first S-UPF to the PSA corresponding to the second session to establish the N9 tunnel of the first S-UPF and the PSA corresponding to the second session, and the A-SMF corresponding to the second session indicates to the first S-SMF that the second session update is successful.

[0217] It should be understood that if the first session and the second session are sessions in different network domains, the N9 tunnel information of the first S-UPF sent to the A-SMF corresponding to the first session and the PSA can be different from the N9 tunnel information of the first S-UPF sent to the A-SMF corresponding to the second session and the PSA. For example, the first tunnel information and the second tunnel information in step 606 can be implemented.

[0218] Optionally, steps 619 to 621 can be implemented in parallel or sequentially for the first session and the second session, and the embodiments of the present application do not limit this.

[0219] It can be understood that in the embodiments corresponding to FIG. 6, the type of the network domain can also be other types except the home network, or the type of the network domain can include multiple types, and the embodiments of the present application do not limit this.

[0220] Based on the embodiments described in FIG. 6, in the future communication system, when the UE moves, the first S-SMF can request the context of multiple sessions of the terminal device by sending a second message to the second S-SMF, and the second S-SMF can return the context of multiple sessions by sending a third message to the first S-SMF. Compared with the existing mobility management process, the number of signaling interactions is reduced, thereby effectively reducing the signaling overhead, improving the processing efficiency of the second S-SMF, and reducing the handover delay of the UE.

[0221] Next, taking the communication system shown in FIG. 3 as an example, the interaction process related to FIG. 4 will be described in detail, wherein:

[0222] (1) 4G communication network to future communication network

[0223] Based on the converged communication system shown in FIG. 3, FIG. 7 shows the function switching (referred to as 4G communication network to future communication network) involved when the UE moves from the service area of the 4G communication network to the service area of the future communication network. In the embodiments of the present application, the future communication network is taken as the 5G communication network as an example. Among them, the first service session management function, the second service session management function, the first mobility management function, the first service user plane function, the session management function corresponding to multiple sessions and the user plane function corresponding to multiple sessions in the corresponding embodiment of FIG. 4 are the first SGW-C+S-SMF, the second SGW-C+S-SMF, the first AMF, the first SGW-U+S-UPF, the PGW-C+SMF in the network domain and the PGW-U+UPF in the network domain in FIG. 7, respectively. The SMF in the PGW-C+network domain is taken as the PGW-C+A-SMF, and the UPF in the PGW-U+network domain is taken as the PGW-U+PSA.

[0224] Before moving, the UE is connected to the 4G communication network, and the UE performs uplink and downlink data transmission with the DN via the E-UTRAN, the second SGW-U+S-UPF and the PGW-U+PSA; the second SGW-U+S-UPF is managed by the second SGW-C+S-SMF, and the PGW-U+PSA is managed by the PGW-C+A-SMF; when the UE moves from the service area of the 4G communication network to the service area of the 5G communication network, the E-UTRAN, the MME, the second SGW-C+S-SMF and the second SGW-U+S-UPF cannot continue to provide services, and need to be switched to the NG-RAN, the first AMF, the first SGW-C+S-SMF and the first SGW-U+S-UPF, respectively. After switching, the UE performs uplink and downlink data transmission with the DN via the NG-RAN, the first SGW-U+S-UPF and the PGW-U+PSA, and the first SGW-U+S-UPF is managed by the first SGW-C+S-SMF.

[0225] Specifically, the interaction process involved in this process can be seen from the flowchart corresponding to FIG. 8, which includes steps 800 to 822, wherein:

[0226] 800, the UE establishes multiple sessions in the 4G communication network through the second SGW-C+S-SMF.

[0227] The multiple sessions (such as EPS sessions) established by the UE in the 4G communication network through the second SGW-C+S-SMF are served by the E-UTRAN, the second SGW-U+S-UPF and the PGW-U+PSA.

[0228] In a possible implementation, the multiple sessions include a first session and a second session, and the PGW-U+PSA corresponding to the first session and the PGW-U+PSA corresponding to the second session can be the same or different.

[0229] 801. The E-UTRAN sends a first handover request message to the MME.

[0230] When the UE moves from a service area of the 4G communication network to a service area of the 5G communication network, the E-UTRAN sends a first handover request (for example, handover required) message to the MME, the first handover request message is used to request the target side to prepare resources, and the first handover request message includes the first location information in the above-mentioned embodiment corresponding to FIG. 4. For example, the first location information can include one or more of the location information of the UE, the location information of the NG-RAN, or the identification information of the coverage area in the NG-RAN. For example, the first location information includes one or more of the latitude and longitude coordinates of the UE, the eNB ID of the NG-RAN, or the TAI of the NG-RAN.

[0231] 802. The MME sends a forward relocation request message to the Initial AMF.

[0232] The Initial AMF is an initial AMF when the UE accesses the 5G communication network. The Initial AMF is used to authenticate, authorize, and obtain network slices for the UE when the UE accesses, so as to realize the update of the session during the mobile switching. The MME sends a forward relocation request (for example, forward relocation request) message to the Initial AMF, the forward relocation request message is used to request to switch the mobility management function serving the UE from the MME to the AMF, and the forward relocation request message carries the first location information and the information of the second SGW-C+S-SMF (for example, one or more of the instance identifier, the IP address, or the FQDN of the second SGW-C+S-SMF).

[0233] 803. The Initial AMF and the second SGW-C+S-SMF transmit a session context creation request message / response message.

[0234] The Initial AMF first confirms the second SGW-C+S-SMF according to the information of the second SGW-C+S-SMF carried in the received forward relocation request message, and then sends a session context creation request (for example, Nsmf_PDUsession_createSMcontext request) message to the second SGW-C+S-SMF. The session context creation request message carries the first location information, and the second SGW-C+S-SMF allocates a network slice identifier for the UE according to the first location information and allocates a context identifier, and the network slice identifier is the network slice identifier corresponding to the plurality of sessions in the 5G communication network, and then sends a session context creation response (for example, Nsmf_PDUsession_createSMcontext response) message to the Initial AMF. The session context creation response message carries the allocated network slice identifier and the context identifier of the plurality of sessions of the UE, and the context identifier of the plurality of sessions of the UE can include the information of the second SGW-C+S-SMF and the identification information (such as one or more of the UE identifier, the EBI of each session, the SM context reference of each session, or the TEID of each session) indicating the plurality of sessions of the terminal device.

[0235] 804. The Initial AMF sends a relocate UE context request message to the first AMF.

[0236] The Initial AMF can first select an AMF (that is, the first AMF) capable of providing services for the UE according to the first location information and / or the network slice identifier. Then, the Initial AMF sends a relocate UE context request (for example, Namf_communication_relocateUEcontext request) message to the first AMF, the relocate UE context request message is used to request switching from the MME to the first AMF, and the relocate UE context request message carries the context identifier of the plurality of sessions of the UE and the first location information. The context identifier can refer to the description in steps 802 and 803, or refer to the description in the corresponding embodiments of the above FIG. 4.

[0237] 805. The first AMF sends a second handover request message to the NG-RAN.

[0238] The first AMF sends a second handover request (for example, handover request) message to the NG-RAN, and the second handover request message is used to request the NG-RAN to prepare resources.

[0239] 806. The NG-RAN sends an acknowledgement message of the second handover request message to the first AMF.

[0240] The NG-RAN sends an acknowledgement (e.g., handover request acknowledge) message to the first AMF for the second handover request message.

[0241] 807. The first AMF sends a first message to the first SGW-C+S-SMF.

[0242] For example, the first message is a PDU session context creation request (e.g., Nsmf_PDUsession_createSMcontext request) message, etc. The first AMF first selects the SGW-C+S-SMF capable of providing services for the UE according to the first location information carried in the received relocation UE context request message in step 804, i.e., the first SGW-C+S-SMF. Then the first AMF sends the first message to the first SGW-C+S-SMF, for requesting the first SGW-C+S-SMF to create session contexts, which can be multiple, corresponding to the multiple sessions in step 800, and the first message carries the context identifier and the first location information.

[0243] 808. The first SGW-C+S-SMF sends a second message to the second SGW-C+S-SMF.

[0244] For example, the second message is a PDU session context request (e.g., Nsmf_PDUsession_context request) message or a retrieve SM context request message, etc. The first SGW-C+S-SMF sends the second message to the second SGW-C+S-SMF through the context identifier (such as the information of the second SGW-C+S-SMF and the identifier information for indicating the multiple sessions of the terminal device) in the received first message, for requesting to obtain the contexts of the multiple sessions, and the second message carries the context identifier.

[0245] 809. The second SGW-C+S-SMF sends a third message to the first SGW-C+S-SMF.

[0246] For example, the third message is a PDU session context response (e.g., Nsmf_PDUsession_context response) message or a retrieve SM context response (e.g., retrieve SM context response) message, etc. According to the context identifier in the received second message, the second SGW-C+S-SMF can confirm the contexts of the multiple sessions of the UE, and then the second SGW-C+S-SMF sends the third message to the first SGW-C+S-SMF, where the third message carries the contexts of the multiple sessions, for example, the contexts of the multiple sessions include the N9 (or S5) tunnel information of the PGW-U+PSA corresponding to each session in the multiple sessions.

[0247] Optionally, the contexts of the multiple sessions can further include one or more of the following: an identifier of each session in the multiple sessions, information of the PGW-C+A-SMF corresponding to each session, an identifier of each session in the corresponding PGW-C+A-SMF, or QoS information corresponding to each session, etc. It should be noted that the PGW-C+A-SMFs corresponding to different sessions can be the same or different, and the embodiments of the present application do not limit this.

[0248] 810. The first SGW-C+S-SMF performs PFCP session establishment with the first SGW-U+S-UPF.

[0249] The first SGW-C+S-SMF first selects the SGW-U+S-UPF capable of providing services for the UE according to the first location information, that is, the first SGW-U+S-UPF, and then sends a PFCP session establishment request message to the first SGW-U+S-UPF, where the PFCP session establishment request message is used to establish a PFCP session. The PFCP session establishment request message carries tunnel information corresponding to each session in the multiple sessions. For example, the PFCP session establishment request message includes N9 (or S5) tunnel information of the PGW-U+PSA corresponding to the first session and N9 (or S5) tunnel information of the PGW-U+PSA corresponding to the second session. The N9 (or S5) tunnel information of the PGW-U+PSA corresponding to the first session and the N9 (or S5) tunnel information of the PGW-U+PSA corresponding to the second session are from the contexts of the multiple sessions received in step 809. The PFCP session establishment request message is also used to request the first SGW-U+S-UPF to allocate N3 tunnel information and N9 (or S5) tunnel information.

[0250] Optionally, if the multiple sessions include sessions in different network domains, the PFCP session establishment request message is also used to request the first SGW-U+S-UPF to allocate different N9 (or S5) tunnel information of the first SGW-U+S-UPF for the sessions in different network domains.

[0251] For example, the first session and the second session are sessions in different home networks respectively, the PGW-U+PSA corresponding to the first session is PGW-U+PSA1, and the PGW-U+PSA corresponding to the second session is PGW-U+PSA2. The first SGW-U+S-UPF can be requested to allocate the N9 (or S5) tunnel information (i.e., first tunnel information and second tunnel information) of the first SGW-U+S-UPF corresponding to PGW-U+PSA1 and PGW-U+PSA2 respectively. The N9 (or S5) tunnel information of the first SGW-U+S-UPF corresponding to PGW-U+PSA1 is different from the N9 (or S5) tunnel information of the first SGW-U+S-UPF corresponding to PGW-U+PSA2.

[0252] It can be understood that the embodiments of the present application are illustrated by taking the home network as an example. When the types of the network domains to which different sessions belong are different, the corresponding N9 (or S5) tunnel information of the first SGW-U+S-UPF can also be allocated in a similar manner.

[0253] 811. The first SGW-C+S-SMF sends a response message of the first message to the first AMF.

[0254] For example, the response message of the first message is a PDU session context creation response (Nsmf_PDUsession_createSMcontextresponse) message or the like, which is used to indicate that the first SGW-C+S-SMF successfully creates the session context, and the response message of the first message carries the tunnel information allocated by the first SGW-U+S-UPF, for example, carries the N3 tunnel information of the first SGW-U+S-UPF.

[0255] 812. The first AMF sends a forward relocation response message to the MME.

[0256] The first AMF sends a forward relocation response (e.g., forward relocation response) message to the MME, and the forward relocation response message is a response message of the forward relocation request message in step 802.

[0257] 813. The first AMF sends a relocation UE context response message to the Initial AMF.

[0258] The first AMF sends a relocation UE context response (e.g., Namf_communication_relocateUEcontextresponse) message to the Initial AMF, and the relocation UE context response message is a response message of the relocation UE context request message in step 804.

[0259] It should be noted that after step 813, the first AMF can also send the N3 tunnel information of the first SGW-U+S-UPF to the NG-RAN. The implementation method can refer to steps 608 and 609 in Figure 6. The NG-RAN can also send the N3 tunnel information of the NG-RAN to the first AMF. The implementation method can refer to steps 610 and 611 in Figure 6, which will not be elaborated here.

[0260] 814. The MME sends the first handover command to the E-UTRAN.

[0261] The MME sends a first handover command (e.g., a handover command) to the E-UTRAN, which notifies the NG-RAN that the NG-RAN is ready to switch over the necessary resources.

[0262] 815. The E-UTRAN sends a second handover command to the UE.

[0263] The E-UTRAN sends a second handover command (e.g., a handover command) to the UE, which instructs the UE to switch from the E-UTRAN to the NG-RAN.

[0264] 816. The UE sends a handover confirmation message to the NG-RAN.

[0265] After the UE switches to NG-RAN, it sends a handover confirmation message (e.g., handover confirm) to NG-RAN. The handover confirmation message is used to indicate that the UE has switched from E-UTRAN to NG-RAN, that is, the handover is complete.

[0266] 817. NG-RAN sends a handover notification message to the first AMF.

[0267] NG-RAN sends a handover notification message (e.g., handover notify) to the first AMF. The handover notification message is used to indicate that the handover is complete.

[0268] 818. The first AMF notifies the first SGW-C+S-SMF that the handover is complete.

[0269] For example, the first AMF sends a PDU session context update request (e.g., Nsmf_PDUsession_updateSMcontextrequest) message to the first SGW-C+S-SMF to indicate that the handover is complete.

[0270] 819. Modify the PFCP session between the first SGW-C+S-SMF and the first SGW-U+S-UPF.

[0271] The first SGW-C+S-SMF sends a PFCP session modification request message to the first SGW-U+S-UPF, e.g., the PFCP session modification request message carries the N3 tunnel information of the NG-RAN, to make the first SGW-U+S-UPF establish the N3 tunnel between the NG-RAN and the first SGW-U+S-UPF based on the received N3 tunnel information of the NG-RAN, and the NG-RAN establish the N3 tunnel between the NG-RAN and the first SGW-U+S-UPF based on the received N3 tunnel information of the first SGW-U+S-UPF.

[0272] 820、The first SGW-C+S-SMF sends a session update request message to the PGW-C+A-SMF.

[0273] The first SGW-C+S-SMF sends a session update request (e.g., Nsmf_PDUSession_UpdateRequest) message to the PGW-C+A-SMF. Taking the first session as an example, the session update request message carries the N9 (or S5) tunnel information of the first SGW-U+S-UPF, and the session update request message is used to request to establish the updated first session, e.g., to request to update the N9 (or S5) tunnel of the first SGW-U+S-UPF to the PGW-U+PSA corresponding to the first session.

[0274] 821、The PGW-C+A-SMF performs PFCP session modification with the PGW-U+PSA.

[0275] The PGW-C+A-SMF sends a PFCP session modification request message to the PGW-U+PSA. Taking the first session as an example, the PFCP session modification request message carries the N9 (or S5) tunnel information of the first SGW-U+S-UPF in step 820, to make the PGW-U+PSA corresponding to the first session establish the N9 tunnel between the PGW-U+PSA and the first SGW-U+S-UPF based on the received N9 (or S5) tunnel information of the first SGW-U+S-UPF, and the first SGW-U+S-UPF establish the N9 tunnel between the first SGW-U+S-UPF and the PGW-U+PSA corresponding to the first session based on the received N9 (or S5) tunnel information of the PGW-U+PSA in step 810.

[0276] 822、The PGW-C+A-SMF sends a session update response message to the first SGW-C+S-SMF.

[0277] The PGW-C+A-SMF sends a session update response (e.g., Nsmf_PDUSession_UpdateResponse) message to the first SGW-C+S-SMF, the session update response message is a response message of the session update request message in step 820, and the session update response message is used to indicate that the session update is successful, such as the first session update is successful.

[0278] The step 810 and the step 822 are detailed implementation manners of the step 405 in the embodiment corresponding to FIG. 4.

[0279] Optionally, if the terminal device establishes the first session and the second session in the step 800, the step 820 to the step 822 can be performed for the first session, and the step 820 to the step 822 can also be performed for the second session, for example, the first SGW-C+S-SMF can also send the N9 (or S5) tunnel information of the first SGW-U+S-UPF to the PGW-C+A-SMF corresponding to the second session, the PGW-C+A-SMF corresponding to the second session can send the N9 (or S5) tunnel information of the first SGW-U+S-UPF to the PGW-U+PSA corresponding to the second session, establish the N9 (or S5) tunnel between the PGW-U+PSA corresponding to the second session and the first SGW-U+S-UPF, and the PGW-C+A-SMF corresponding to the second session indicates to the first SGW-C+S-SMF that the second session update is successful.

[0280] It should be understood that if the first session and the second session are sessions in different network domains, the N9 (or S5) tunnel information of the first SGW-U+S-UPF sent to the PGW-C+A-SMF and the PGW-U+PSA corresponding to the first session can be different from the N9 (or S5) tunnel information of the first SGW-U+S-UPF sent to the PGW-C+A-SMF and the PGW-U+PSA corresponding to the second session. For example, the first tunnel information and the second tunnel information in the step 810.

[0281] Optionally, the step 820 to the step 822 can be performed for the first session and the step 820 to the step 822 can be performed for the second session in parallel or sequentially, and the embodiments of the present application do not limit this.

[0282] It can be understood that in the embodiment corresponding to FIG. 8, the type of the network domain can also be a type other than a home network, or the type of the network domain can include multiple types, and the embodiments of the present application do not limit this.

[0283] Based on the embodiment described in Figure 8, in a converged communication system, when a UE moves from the service area of ​​a 4G communication network to the service area of ​​a future communication network, the first SGW-C+S-SMF can request the context of multiple sessions of the terminal device by sending a second message to the second SGW-C+S-SMF, and the second SGW-C+S-SMF can return the context of multiple sessions by sending a third message to the first SGW-C+S-SMF. Compared with existing mobility management procedures, this process reduces the number of signaling interactions, thereby effectively reducing signaling overhead and improving the processing efficiency of the second SGW-C+S-SMF, thus reducing the UE's handover latency.

[0284] (2) Future communication network switching to 4G communication network

[0285] Based on the converged communication system shown in Figure 3, Figure 9 illustrates the function handover involved when a UE moves from the service area of ​​a future communication network to the service area of ​​a 4G communication network (referred to as future communication network to 4G communication network switch). In this embodiment, the future communication network is taken as a 5G communication network. The first service session management function, second service session management function, first mobility management function, first service user plane function, session management function corresponding to multiple sessions, and user plane function corresponding to multiple sessions in the embodiment corresponding to Figure 4 are, in order, the first SGW-C+S-SMF, second SGW-C+S-SMF, MME, first SGW-U+S-UPF, SMF in the PGW-C+ network domain, and UPF in the PGW-U+ network domain in Figure 9. The SMF in the PGW-C+ network domain is exemplified by PGW-C+A-SMF, and the UPF in the PGW-U+ network domain is exemplified by PGW-C+PSA.

[0286] Before moving, the UE connects to the 5G communication network. The UE transmits uplink and downlink data with the DN via NG-RAN, the second SGW-U+S-UPF, and PGW-U+PSA. The second SGW-U+S-UPF is managed by the second SGW-C+S-SMF, and the PGW-U+PSA is managed by the PGW-C+A-SMF. When the UE moves from the service area of ​​the 5G communication network to the service area of ​​the 4G communication network, NG-RAN, AMF, the second SGW-C+S-SMF, and the second SGW-U+S-UPF can no longer provide services and must be switched to E-UTRAN, MME, the first SGW-C+S-SMF, and the first SGW-U+S-UPF, respectively. After the switchover, the UE transmits uplink and downlink data with the DN via E-UTRAN, the first SGW-U+S-UPF, and PGW-U+PSA. The first SGW-U+S-UPF is managed by the first SGW-C+S-SMF.

[0287] Specifically, the interaction flow involved in the process can be seen from the flowchart corresponding to FIG. 10, including steps 1000 to 1023, wherein:

[0288] 1000, the UE establishes multiple sessions in the 5G communication network through the second SGW-C+S-SMF.

[0289] The multiple sessions (such as PDU sessions) established by the UE in the 5G communication network through the second SGW-C+S-SMF are served by the NG-RAN, the second SGW-U+S-UPF, and the PGW-U+PSA.

[0290] In a possible implementation, the multiple sessions include a first session and a second session, and the PGW-U+PSA corresponding to the first session and the PGW-U+PSA corresponding to the second session can be the same or different.

[0291] 1001, the NG-RAN sends a first handover request message to the AMF.

[0292] When the UE moves across the service area of the 4G communication network from the service area of the 5G communication network, the NG-RAN sends a first handover request (for example, handover required) message to the AMF, the first handover request message is used to request the target side to prepare resources, and the first handover request message includes the first location information in the above-mentioned embodiment corresponding to FIG. 4, for example, the first location information can include but is not limited to one or more of the location information of the UE, the location information of the E-UTRAN, or the identification information of the coverage area in the E-UTRAN. For example, the first location information includes one or more of the latitude and longitude coordinates of the UE, the eNB ID of the E-UTRAN, or the TAI of the E-UTRAN.

[0293] 1002, the AMF sends a session context request message to the second SGW-C+S-SMF.

[0294] For example, the session context request message is a PDU session context request (for example, Nsmf_PDUsession_contextrequest) message, and the session context request message carries the first location information.

[0295] 1003, the second SGW-C+S-SMF sends a session context response message to the AMF.

[0296] For example, the session context response message is a PDU session context response (e.g., Nsmf_PDUsession_contextresponse) message, the session context response message carries information of a plurality of EPS PDN connections mapped by the plurality of sessions under the 4G communication network and context identifiers of the plurality of sessions of the UE. The context identifiers of the plurality of sessions of the UE can include information of the second SGW-C+S-SMF (such as one or more of an instance identifier, an IP address or a FQDN of the second SGW-C+S-SMF) and identification information for indicating the plurality of sessions of the terminal device (such as one or more of including an identifier of the UE, a PDU session ID of each session, an SM context reference of each session or a TEID of each session).

[0297] 1004. The AMF sends a relocation request message to the MME.

[0298] The AMF sends a relocation request (e.g., relocation request) message to the MME. The relocation request message is used to request to switch the mobility management function serving the UE from the AMF to the MME, and the relocation request message carries the first location information, the context identifier and the EPS PDN connections mapped by the plurality of sessions under the 4G communication network.

[0299] 1005. The MME sends a first message to the first SGW-C+S-SMF.

[0300] For example, the first message is a session creation request (e.g., create session request) message, etc., the first message is used to request to create session contexts for the second SGW-C+S-SMF switched to the first SGW-C+S-SMF, the session contexts can be a plurality of, corresponding to the plurality of sessions of step 1000, and the first message carries the context identifier and the first location information.

[0301] 1006. The first SGW-C+S-SMF sends a second message to the second SGW-C+S-SMF.

[0302] For example, the second message is a PDU session context request (e.g., Nsmf_PDUsession_contextrequest) message or a retrieve SM context request message, etc. The first SGW-C+S-SMF sends, to the second SGW-C+S-SMF, the second message for requesting to obtain the contexts of the multiple sessions according to the context identifier in the received first message (such as the information of the second SGW-C+S-SMF and the identifier information for indicating the multiple sessions of the terminal device), and the second message carries the context identifier.

[0303] 1007. The second SGW-C+S-SMF sends a third message to the first SGW-C+S-SMF.

[0304] For example, the third message is a PDU session context response (e.g., Nsmf_PDUsession_context response) message or a retrieve SM context response message, etc. The second SGW-C+S-SMF can confirm the contexts of the multiple sessions of the UE according to the context identifier in the received second message, and then the second SGW-C+S-SMF sends, to the first SGW-C+S-SMF, the third message carrying the contexts of the multiple sessions, for example, the contexts of the multiple sessions include the S5 (or N9) tunnel information of the PGW-U+PSA corresponding to each session in the multiple sessions.

[0305] Optionally, the contexts of the multiple sessions can further include one or more of the following: the identifier of each session in the multiple sessions, the information of the PGW-C+A-SMF corresponding to each session, the identifier of each session in the corresponding PGW-C+A-SMF, or the QoS information corresponding to each session, etc. It should be noted that the PGW-C+A-SMFs corresponding to different sessions can be the same or different, and the embodiments of the present application do not limit this.

[0306] 1008. The first SGW-C+S-SMF performs PFCP session establishment with the first SGW-U+S-UPF.

[0307] The first SGW-C+S-SMF selects a SGW-U+S-UPF capable of providing services for the UE according to the first location information, i.e., a first SGW-U+S-UPF, and then sends a PFCP session establishment request message to the first SGW-U+S-UPF, where the PFCP session establishment request message is used to establish a session between the first SGW-C+S-SMF and the first SGW-U+S-UPF. The PFCP session establishment request message carries tunnel information corresponding to each session of multiple sessions. For example, the PFCP session establishment request message includes S5 (or N9) tunnel information of a PGW-U+PSA corresponding to a first session and S5 (or N9) tunnel information of a PGW-U+PSA corresponding to a second session, and the PFCP session establishment request message is also used to request the first SGW-U+S-UPF to allocate S1-U tunnel information and S5 (or N9) tunnel information.

[0308] Optionally, if the multiple sessions include sessions in different network domains, the PFCP session establishment request message is also used to request the first SGW-U+S-UPF to allocate different S5 (or N9) tunnel information of the first SGW-U+S-UPF for the sessions in different network domains.

[0309] For example, the first session and the second session are sessions in different home networks respectively, the PGW-U+PSA corresponding to the first session is PGW-U+PSA1, and the PGW-U+PSA corresponding to the second session is PGW-U+PSA2, the first SGW-U+S-UPF can be requested to allocate S5 (or N9) tunnel information (i.e., first tunnel information and second tunnel information) of the first SGW-U+S-UPF corresponding to PGW-U+PSA1 and PGW-U+PSA2 respectively. The S5 (or N9) tunnel information of the first SGW-U+S-UPF corresponding to PGW-U+PSA1 is different from the S5 (or N9) tunnel information of the first SGW-U+S-UPF corresponding to PGW-U+PSA2.

[0310] It can be understood that the embodiments of the present application are described by taking the home network as an example, and when the types of network domains to which different sessions belong are different, the corresponding S5 (or N9) tunnel information of the first SGW-U+S-UPF can also be allocated in a similar manner.

[0311] 1009、The first SGW-C+S-SMF sends a response message of the first message to the MME.

[0312] For example, the response message of the first message is a session creation response (e.g., create session response) message, etc., used to indicate that the first SGW-C+S-SMF successfully creates the session, and the response message of the first message carries the tunnel information allocated by the first SGW-U+S-UPF, for example, carries the S1-U tunnel information of the first SGW-U+S-UPF.

[0313] 1010. The MME sends a second handover request message to the E-UTRAN.

[0314] The MME sends a second handover request (e.g., handover request) message to the E-UTRAN, and the second handover request message is used to request the E-UTRAN to prepare resources.

[0315] 1011. The E-UTRAN sends an acknowledgement message of the second handover request message to the MME.

[0316] The E-UTRAN sends a handover request acknowledge message to the MME.

[0317] It should be noted that after step 1011, the MME can also send the S1-U tunnel information of the first SGW-U+S-UPF to the E-UTRAN, and the implementation manner can refer to steps 608 and 609 in FIG. 6, and the E-UTRAN can send the S1-U tunnel information of the E-UTRAN to the MME, and the implementation manner can refer to steps 610 and 611 in FIG. 6, which will not be described herein.

[0318] 1012. The MME sends a relocation response message to the AMF.

[0319] The MME sends a relocation response (e.g., relocation response) message to the AMF, and the relocation response message is a response message of the relocation request message in step 1004.

[0320] 1013. The AMF sends a first handover instruction to the NG-RAN.

[0321] The AMF sends a first handover instruction (e.g., handover command) to the NG-RAN, and the first handover instruction is used to inform the NG-RAN that the E-UTRAN has prepared the required resources for the handover.

[0322] 1014. The NG-RAN sends a second handover instruction to the UE.

[0323] The NG-RAN sends a second handover instruction (e.g., handover command) to the UE, the second handover instruction being used to instruct the UE to handover from the NG-RAN to the E-UTRAN.

[0324] 1015. The UE sends a handover confirm message to the E-UTRAN.

[0325] After the UE handovers to the E-UTRAN, the UE sends a handover confirm (e.g., handover confirm) message to the E-UTRAN, the handover confirm message being used to indicate that the UE has handover from the NG-RAN to the E-UTRAN, i.e., the handover is completed.

[0326] 1016. The E-UTRAN sends a handover notification message to the MME.

[0327] The E-UTRAN sends a handover notify (e.g., handover notify) message to the MME, the handover notify message being used to indicate that the handover is completed.

[0328] 1017. The MME notifies the AMF that the handover is completed.

[0329] 1018. The MME sends a first bearer modification request message to the first SGW-C+S-SMF.

[0330] The MME sends a first bearer modification request (e.g., modify bearer request) message to the first SGW-C+S-SMF, for example, the first bearer modification request message carrying S1-U tunnel information of the E-UTRAN.

[0331] 1019. The first SGW-C+S-SMF performs PFCP session modification with the first SGW-U+S-UPF.

[0332] The first SGW-C+S-SMF sends a PFCP session modification request message to the first SGW-U+S-UPF, for example, the PFCP session modification request message carrying S1-U tunnel information of the E-UTRAN, so that the first SGW-U+S-UPF establishes S1-U tunnel between the E-UTRAN and the first SGW-U+S-UPF based on the received S1-U tunnel information of the E-UTRAN, and the E-UTRAN establishes S1-U tunnel between the E-UTRAN and the first SGW-U+S-UPF based on the received S1-U tunnel information of the first SGW-U+S-UPF.

[0333] 1020. The first SGW-C+S-SMF sends a second bearer modification request message to the PGW-C+A-SMF.

[0334] The first SGW-C+S-SMF sends a second bearer modification request (e.g., modify bearer Request) message to the PGW-C+A-SMF. For example, the second bearer modification request message carries the S5 (or N9) tunnel information of the first SGW-U+S-UPF, and the session update request message is used to request to establish update the first session, for example, update the S5 (or N9) tunnel of the first SGW-U+S-UPF to the PGW-U+PSA corresponding to the first session.

[0335] 1021. The PGW-C+A-SMF performs a PFCP session modification with the PGW-U+PSA.

[0336] The PGW-C+A-SMF sends a PFCP session modification request message to the PGW-U+PSA. For example, the PFCP session modification request message carries the S5 (or N9) tunnel information of the first SGW-U+S-UPF in step 1020, so that the PGW-U+PSA corresponding to the first session establishes the S5 (or N9) tunnel of the first SGW-U+S-UPF based on the received S5 (or N9) tunnel information of the first SGW-U+S-UPF and the S5 (or N9) tunnel information of the PGW-U+PSA corresponding to the first session received by the first SGW-U+S-UPF based on step 1007.

[0337] 1022. The PGW-C+A-SMF sends a second bearer modification response message to the first SGW-C+S-SMF.

[0338] The PGW-C+A-SMF sends a second bearer modification response (e.g., modify bearer response) message to the first SGW-C+S-SMF, and the second bearer modification response message is a response message of the second bearer modification request message in step 1020.

[0339] 1023. The first SGW-C+S-SMF sends a first bearer modification response message to the MME.

[0340] The first SGW-C+S-SMF sends a first bearer modification response (e.g., modify bearer response) message to the MME, and the first bearer modification response message is a response message of the first bearer modification request message in step 1018. The first bearer modification response message is used to indicate that the session update is successful, for example, the first session update is successful.

[0341] The above step 1008 and step 1023 are detailed implementation manners of step 405 in the embodiment corresponding to FIG. 4.

[0342] Optionally, if the terminal device establishes the first session and the second session in step 1000, step 1020 to step 1023 can be performed for the first session, and step 1020 to step 1023 can also be performed for the second session. For example, the first SGW-C+S-SMF can also send the S5 (or N9) tunnel information of the first SGW-U+S-UPF to the second session corresponding PGW-C+A-SMF, the second session corresponding PGW-C+A-SMF can send the S5 (or N9) tunnel information of the first SGW-U+S-UPF (i.e. the second tunnel information) to the second session corresponding PGW-U+PSA, establish the S5 (or N9) tunnel between the second session corresponding PGW-U+PSA and the first SGW-U+S-UPF, and the second session corresponding PGW-C+A-SMF indicates to the first SGW-C+S-SMF and the first SGW-C+S-SMF indicates to the MME that the second session update is successful.

[0343] It should be understood that if the first session and the second session are sessions in different network domains, the S5 (or N9) tunnel information of the first SGW-U+S-UPF sent to the first session corresponding PGW-C+A-SMF and PGW-U+PSA can be different from the S5 (or N9) tunnel information of the first SGW-U+S-UPF sent to the second session corresponding PGW-C+A-SMF and PGW-U+PSA. For example, the first tunnel information and the second tunnel information in step 1008.

[0344] Optionally, step 1020 to step 1023 can be performed for the first session and step 1020 to step 1023 can be performed for the second session in parallel or sequentially, and the embodiments of the present application do not limit this.

[0345] It can be understood that in the embodiment corresponding to FIG. 8, the type of the network domain can also be other than the home network, or the type of the network domain can include multiple types, and the embodiments of the present application do not limit this.

[0346] Based on the embodiment described in FIG. 10, in the converged communication system, when the UE moves from the service area of the future communication network to the service area of the 4G communication network, the first SGW-C+S-SMF can request the context of the multiple sessions of the terminal device by sending a second message to the second SGW-C+S-SMF, and the second SGW-C+S-SMF can return the context of the multiple sessions by sending a third message to the first SGW-C+S-SMF. Compared with the existing mobility management process, the number of signaling interactions is reduced, thereby effectively reducing the signaling overhead, improving the processing efficiency of the second SGW-C+S-SMF, and reducing the handover delay of the UE.

[0347] FIG. 11 shows a structural schematic diagram of a communication apparatus according to an embodiment of the present application. The communication apparatus 1100 shown in FIG. 11 can include a transceiver unit 1101 and a processing unit 1102.

[0348] In an example, the communication apparatus 1100 shown in FIG. 11 can be configured to perform part or all of the functions of the first service session management function in the above-described embodiments. The communication apparatus 1100 can be the first service session management function, or a device in the first service session management function, or a device that can be used in conjunction with the first service session management function. The communication apparatus 1100 can also be a chip system. In this case:

[0349] The transceiver unit 1101 is configured to receive a first message from a first mobility management function, the first message being used to request switching of a terminal device from a second service session management function to the first service session management function, the service session management function being used to manage multiple sessions of the terminal device; send a second message to the second service session management function, the second message being used to obtain the context of the multiple sessions of the terminal device; and receive a third message from the second service session management function, the third message including the context of the multiple sessions of the terminal device.

[0350] The processing unit 1102 is configured to update the multiple sessions based on the context of the multiple sessions.

[0351] In a possible implementation, the second message includes a context identifier of the multiple sessions of the terminal device, the context identifier being used to indicate the multiple sessions of the terminal device on the second service session management function.

[0352] In a possible implementation, the first message includes the context identifier and first location information, the first location information being used to indicate the location of the terminal device.

[0353] In a possible implementation, the context of the multiple sessions includes tunnel information of user plane functions corresponding to the multiple sessions; and the processing unit 1102 is specifically configured to: select a first service user plane function based on the context of the multiple sessions, and send the tunnel information of the user plane functions corresponding to the multiple sessions to the first service user plane function, and send tunnel information of the first service user plane function to a session management function corresponding to the multiple sessions.

[0354] In a possible implementation, the session management function corresponding to the multiple sessions includes a first session management function and a second session management function; and the sending of the tunnel information of the first service user plane function to the session management function corresponding to the multiple sessions includes: sending first tunnel information of the first service user plane function to the first session management function, and sending second tunnel information of the first service user plane function to the second session management function.

[0355] In another example, the communication apparatus 1100 shown in FIG. 11 can be used to perform part or all of the functions of the second service session management function in the above-described embodiments. The communication apparatus 1100 can be the second service session management function, can be a device in the second service session management function, or can be a device capable of being used in matching with the second service session management function. The communication apparatus 1100 can also be a chip system.

[0356] In a possible implementation, the communication apparatus 1100 includes a receiving unit 1101 and a processing unit 1102, and the receiving unit 1101 is configured to: receive a second message from a first service session management function, the second message being used to obtain a context of multiple sessions of a terminal device; and send a third message to the first service session management function, the third message including the context of the multiple sessions of the terminal device; and the processing unit 1102 is configured to: select a first service session management function based on first location information, the first location information being used to indicate a location of the terminal device.

[0357] The transceiving unit 1101 is configured to: receive a second message from a first service session management function, the second message being used to obtain a context of multiple sessions of a terminal device; and send a third message to the first service session management function, the third message including the context of the multiple sessions of the terminal device; and the processing unit 1102 is configured to: select a first service session management function based on first location information, the first location information being used to indicate a location of the terminal device.

[0358] In a possible implementation, the second message includes a context identifier of the multiple sessions of the terminal device, and the context identifier is used to indicate the multiple sessions of the terminal device on the second service session management function.

[0359] In another example, the communication apparatus 1100 shown in FIG. 11 can be used to perform part or all of the functions of the first mobility management function in the above-described embodiments. The communication apparatus 1100 can be the first mobility management function, can be a device in the first mobility management function, or can be a device capable of being used in matching with the first mobility management function. The communication apparatus 1100 can also be a chip system.

[0360] The processing unit 1102 is configured to: select a first service session management function based on first location information, the first location information being used to indicate a location of the terminal device.

[0361] The transceiver 1101 is configured to send, to the first service session management function, a first message, the first message being used to request switching of the terminal device from the second service session management function to the first service session management function, the service session management function being used to manage multiple sessions of the terminal device.

[0362] In a possible implementation, the first message includes context identification of the multiple sessions of the terminal device and the first location information, the context identification being used to indicate the multiple sessions of the terminal device on the second service session management function.

[0363] In a possible implementation, before selecting the first service session management function based on the first location information, the processing unit 1102 further includes that the transceiver 1101 is configured to receive a fourth message sent by the second mobility management function, the fourth message including the context identification and the first location information.

[0364] In a possible implementation, the context identification includes information of the second service session management function.

[0365] It should be noted that the specific implementation and advantages of the operations performed by the communication apparatus 1100 can be referred to the corresponding description in the above method embodiments, which will not be described here.

[0366] FIG. 12 shows a structural schematic diagram of another communication apparatus according to the embodiments of the present application, which is used to implement the functions of the first service session management function, the second service session management function or the first mobility management function in the above method embodiments. The communication apparatus 1200 can be the first service session management function, the second service session management function or the first mobility management function, or an apparatus for the first service session management function, the second service session management function or the first mobility management function. The apparatus for the first service session management function, the second service session management function or the first mobility management function can be a chip system or a chip. The chip system can be composed of a chip, or can include the chip and other discrete devices.

[0367] The communication apparatus 1200 comprises at least one processor 1201 configured to implement the data processing functions of the first service session management function, the second service session management function or the first mobility management function in the method according to the embodiments of the present application. The communication apparatus 1200 can also comprise a communication interface 1202 configured to implement the transceiving operation of the first service session management function, the second service session management function or the first mobility management function in the method according to the embodiments of the present application. In the embodiments of the present application, the communication interface can be a transceiver, a circuit, a bus, a module or other types of communication interfaces, configured to communicate with other devices through transmission media. For example, the communication interface 1202 is configured to enable the communication apparatus 1200 to communicate with other devices. The processor 1201 transceives data through the communication interface 1202, and is configured to implement the method in the above method embodiments.

[0368] The communication apparatus 1200 can also comprise at least one memory 1203 configured to store program instructions and / or data. The memory 1203 is coupled to the processor 1201. The coupling between the devices, units or modules in the embodiments of the present application is indirect coupling or communication connection between the devices, units or modules, which can be electrical, mechanical or other forms, configured to enable the information interaction between the devices, units or modules. The processor 1201 can operate in cooperation with the memory 1203. The processor 1201 can execute the program instructions stored in the memory 1203. At least one of the at least one memory 1203 can be included in the processor 1201.

[0369] When the communication apparatus 1200 is powered on, the processor 1201 can read the software program in the memory 1203, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be transmitted wirelessly, the processor 1201 performs baseband processing on the data to be transmitted, and outputs the baseband signal to a radio frequency circuit (not shown in the figure), which converts the baseband signal into a radio frequency signal and transmits the radio frequency signal in the form of electromagnetic waves through an antenna. When data is transmitted to the communication apparatus 1200, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor 1201, which converts the baseband signal into data and processes the data.

[0370] In another implementation, the radio frequency circuit and the antenna can be arranged independently of the processor 1201 performing baseband processing, for example, in a distributed scenario, the radio frequency circuit and the antenna can be arranged remotely from the communication apparatus.

[0371] The specific connection medium between the communication interface 1202, the processor 1201 and the memory 1203 in the embodiments of the present application is not limited. In FIG. 12, the memory 1203, the processor 1201 and the communication interface 1202 are connected through a bus 1204, which is represented by a thick line in FIG. 12, and the connection mode between other components is only illustrative and is not limited. The bus can be divided into an address bus, a data bus, a control bus and the like. For convenience of representation, only one thick line is used in FIG. 12, but it does not mean that there is only one bus or only one type of bus.

[0372] When the communication device 1200 is specifically a device for a first service session management function, a second service session management function or a first mobility management function, for example, the communication device 1200 is specifically a chip or a chip system, the communication interface 1202 can output or receive a baseband signal. When the communication device 1200 is specifically a first service session management function, a second service session management function or a first mobility management function, the communication interface 1202 can output or receive a radio frequency signal. In the embodiments of the present application, the processor can be a general processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, and can implement or execute the disclosed methods, operations and logic block diagrams in the embodiments of the present application. The general processor can be a microprocessor or any conventional processor. The operations of the method disclosed in combination with the embodiments of the present application can be directly embodied as execution completed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

[0373] The embodiments of the present application also provide a computer readable storage medium, which stores a computer program, when the computer program is run on a processor, the method flow of the method embodiments is realized.

[0374] The embodiments of the present application also provide a computer program product, when the computer program product is run on a computer, the method flow of the method embodiments is realized.

[0375] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all described as a series of action combinations, but those skilled in the art should know that the present application is not limited to the order of the actions described, because according to the present application, certain operations can be performed in other order or at the same time. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0376] The descriptions of the various embodiments provided by the present application can be referred to each other, and the descriptions of the various embodiments are each focused on. The parts not described in detail in a certain embodiment can be referred to the relevant descriptions of other embodiments. For the convenience and brevity of description, for example, the functions of the various devices and the operations performed by the devices provided by the embodiments of the present application can be referred to the relevant descriptions of the method embodiments of the present application, and the various method embodiments can also be referred to, combined or cited each other.

[0377] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.) mode. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media sets. The available medium can be a magnetic medium (for example, floppy disk, hard disk, magnetic tape), an optical medium (for example, DVD), or a semiconductor medium (for example, solid state drive (SSD)) and the like.

Claims

1. A communication method characterized by comprising: The method applied to a first service session management function comprises: receiving a first message from a first mobility management function, the first message being used to request switching a terminal device from a second service session management function to the first service session management function, a service session management function being used to manage multiple sessions of the terminal device; sending a second message to the second service session management function, the second message being used to acquire contexts of the multiple sessions of the terminal device; receiving a third message from the second service session management function, the third message comprising the contexts of the multiple sessions of the terminal device; updating the multiple sessions based on the contexts of the multiple sessions.

2. The method of claim 1, wherein, The second message comprises context identifiers of the multiple sessions of the terminal device, the context identifiers being used to indicate the multiple sessions of the terminal device on the second service session management function.

3. The method of claim 2, wherein, The first message comprises the context identifiers and first location information, the first location information being used to indicate a location of the terminal device.

4. The method of claim 3, wherein, The contexts of the multiple sessions comprise tunnel information of user plane functions corresponding to the multiple sessions. The updating the multiple sessions based on the contexts of the multiple sessions comprises: selecting a first service user plane function based on the first location information; sending the tunnel information of the user plane functions corresponding to the multiple sessions to the first service user plane function; sending tunnel information of the first service user plane function to session management functions corresponding to the multiple sessions.

5. The method of claim 4, wherein, The session management functions corresponding to the multiple sessions comprise a first session management function and a second session management function. The sending the tunnel information of the first service user plane function to the session management functions corresponding to the multiple sessions comprises: sending first tunnel information of the first service user plane function to the first session management function; sending second tunnel information of the first service user plane function to the second session management function.

6. A communication method characterized by comprising: The method applied to a second service session management function comprises: receiving a second message from a first service session management function, the second message being used to acquire contexts of multiple sessions of a terminal device; sending a third message to the first service session management function, the third message comprising the contexts of the multiple sessions of the terminal device; wherein a service session management function is used to manage the multiple sessions of the terminal device.

7. The method of claim 6, wherein, The second message comprises context identifiers of the multiple sessions of the terminal device, the context identifiers being used to indicate the multiple sessions of the terminal device on the second service session management function.

8. A communication method characterized by comprising: The method applied to a first mobility management function comprises: selecting a first service session management function based on first location information, the first location information being used to indicate a location of a terminal device; sending a first message to the first service session management function, the first message being used to request switching the terminal device from a second service session management function to the first service session management function, a service session management function being used to manage multiple sessions of the terminal device.

9. The method of claim 8, wherein, The first message comprises context identification of multiple sessions of the terminal device and the first location information, the context identification being used to indicate multiple sessions of the terminal device on the second service session management function.

10. The method according to claim 8 or 9, characterized in that, Before selecting the first service session management function based on the first location information, the method further comprises: receiving a fourth message sent from the second mobility management function, the fourth message comprising context identification and the first location information.

11. The method of claim 10, wherein, The context identification comprises information of the second service session management function.

12. A communications device, characterized by comprising units for performing the method according to any one of claims 1-5 or claims 6-7 or claims 8-11.

13. A communications device, characterized by comprising a processor and a memory, the processor and the memory being coupled, the processor being configured to implement the method according to any one of claims 1-5 or claims 6-7 or claims 8-11.

14. A chip, characterized by comprising a processor and an interface, the interface being configured to receive or output signals, the processor being configured to execute code instructions, so that the chip implements the method according to any one of claims 1-5 or claims 6-7 or claims 8-11.

15. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, the computer program, when invoked by the computer, causing the computer to execute the method according to any one of claims 1-5 or claims 6-7 or claims 8-11.

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