Communication method, communication device and communication system

Abstract

The invention provides a communication method, a communication device and a communication system. The method comprises the following steps: when a session of one terminal (namely a first terminal) in two terminals for transmitting the same message of the same equipment is registered to a first user plane network element, and a session of the other terminal (namely a second terminal) is not registered to the first user plane network element; if the first user plane network element queries that the second terminal is registered to the second user plane network element, the first user plane network element requests to register the session of the first terminal on the first user plane network element and re-register the session of the first terminal to the second user plane network element; according to the invention, the same user plane network element (namely the second user plane network element) directly receives the same message from the first terminal and the second terminal, and the received same message is subjected to double-transmitting selective receiving, so that the service continuity is guaranteed, and the double-transmitting selective receiving effect is improved.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a communication method, communication device and communication system. Background Technology

[0002] In current industrial control scenarios, industrial equipment (such as robots and robotic arms) can utilize 5G networks for data transmission. To improve transmission reliability, a dual-transmission and selective-reception scheme is proposed. Specifically, industrial equipment accesses the 5G network through an industrial gateway. This gateway has two built-in 5G local area network (LAN) modules, each accessing the 5G network via different wireless frequencies. In the uplink direction, the industrial equipment sends a message to the industrial gateway. The gateway duplicates the message and transmits the two identical messages separately through different 5G LAN modules. The network side (e.g., user plane network elements) forwards the first received message (e.g., to the application server) according to the "first-come, first-served, last-discard" principle, discarding the second received message. In the downlink direction, the application server sends a message to the network side (e.g., user plane network elements). The network side replicates the message, sending the two identical messages to different 5G LAN modules of the industrial gateway. The industrial gateway forwards the first received message (e.g., to industrial equipment) according to the "first-in, first-out" principle, discarding the second received message. Based on this scheme, the sending end sends the same message through two links, achieving redundant message transmission. Even if one of the identical messages is lost during transmission, the receiving end can still receive the other message, thus improving transmission reliability and reducing transmission latency.

[0003] In the dual-transmission selective reception scheme, to further improve transmission reliability, a primary and backup deployment of user plane network elements is proposed, that is, deploying two user plane network elements in the network that are mutually primary and backup. Under normal circumstances, both terminals register with the primary user plane network element through a session establishment process, and the primary user plane network element implements the dual-transmission selective reception function. When the primary user plane network element goes offline or is overloaded due to some reason (such as a fault), both terminals register with the backup user plane network element through a session modification process or a session reconstruction process, and the backup user plane network element implements the dual-transmission selective reception function. In practical applications, when the primary user plane network element goes offline or is overloaded, only one terminal may successfully re-register with the backup user plane network element, while the other terminal may fail to register. For example, if the primary user plane network element goes offline or is under heavy load, and one terminal successfully re-registers to the backup user plane network element, but the primary user plane network element comes back online or its load returns to normal before the other terminal successfully registers to the backup user plane network element, then the other terminal continues to be registered to the primary user plane network element, resulting in one terminal registered to the primary user plane network element and the other registered to the backup user plane network element. As another example, if the primary user plane network element goes offline or is under heavy load, and one terminal successfully re-registers to the backup user plane network element, but the other terminal fails to register to the backup user plane network element for some reason, then only one terminal is registered to the backup user plane network element, and the other terminal is neither registered to the primary user plane network element nor the backup user plane network element.

[0004] In the scenario described above, where only one terminal is registered to the backup user plane network element, how to ensure service continuity and the effectiveness of dual-transmission selective reception remains to be addressed. Summary of the Invention

[0005] This application provides a communication method, communication device, and communication system to ensure service continuity and the effectiveness of dual-transmission and selective reception.

[0006] In a first aspect, embodiments of this application provide a communication method that can be applied to the network side, such as a first user plane network element on the network side, a module (e.g., circuit, chip, or chip system) within the first user plane network element, or a logical node, logical module, or software capable of implementing all or part of the functions of the first user plane network element. The method includes: determining that a session of a first terminal is registered to the first user plane network element and a session of a second terminal is not registered to the first user plane network element; sending a query request, the query request being used to query whether the session of the second terminal has been registered to the second user plane network element; receiving a query response, the query response being used to indicate that the session of the second terminal has been registered to the second user plane network element; and, according to the query response, sending a request message, the request message being used to request the deregistration of the session of the first terminal and the reregistration of the session of the first terminal to the second user plane network element; wherein the first terminal and the second terminal are used to transmit the same message from the same device, and the second user plane network element is used to forward the received same message from either the first terminal or the second terminal.

[0007] Based on the above scheme, when one of the two terminals (i.e., the first terminal) used to transmit the same message from the same device has its session registered with the first user plane network element, while the other terminal (i.e., the second terminal) has not registered its session with the first user plane network element, and the first user plane network element finds that the second terminal has already registered with the second user plane network element, then the first user plane network element requests to register the first terminal's session on the first user plane network element and re-register the first terminal's session with the second user plane network element. This enables the same user plane network element (i.e., the second user plane network element) to directly receive the same message from both the first and second terminals, and to perform dual-transmission and selective reception of the received same message. Therefore, it not only ensures service continuity but also improves the dual-transmission and selective reception effect.

[0008] In one possible implementation, sending the query request includes sending the query request to the second user plane network element; correspondingly, receiving the query response includes receiving the query response from the second user plane network element.

[0009] Based on the above scheme, querying the second user plane network element to see if the second terminal's session has been registered with the second user plane network element can ensure the accuracy of the query results.

[0010] In one possible implementation, sending the query request includes: sending the query request to the session management network element corresponding to the data network name (DNN); wherein the DNN corresponds to the session of the first terminal and the session of the second terminal; correspondingly, receiving the query response includes: receiving the query response from the session management network element.

[0011] Based on the above scheme, querying the session management network element corresponding to the DNN to see if the session of the second terminal has been registered to the second user plane network element can ensure the accuracy of the query results.

[0012] One possible implementation further includes: receiving a message from the first terminal; and sending the message from the first terminal to the second user plane network element.

[0013] Based on the above scheme, after the first user plane network element receives the message from the first terminal, it forwards the message to the second user plane network element, which then forwards the message instead of discarding it. This prevents service interruption and ensures service continuity.

[0014] In one possible implementation, the query response carries a pair identifier; or, the query response carries a pair identifier and the identifier of the second terminal; or, the query response carries a DNN and the identifier of the second terminal; or, the query response carries a pair identifier, the identifier of the second terminal, and indication information; or, the query response carries a DNN, the identifier of the second terminal, and indication information; wherein, the pair identifier is used to indicate that the first terminal and the second terminal form a pair of terminals, the pair of terminals are used to transmit the same message from the same device, the DNN corresponds to the session of the first terminal and the session of the second terminal, and the indication information is used to indicate that the session of the second terminal has been registered to the second user plane network element.

[0015] In one possible implementation, determining that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element includes: determining that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element based on information indicating that the first terminal and the second terminal are used to transmit the same message of the same device.

[0016] Based on the above scheme, when it is determined that the first terminal and the second terminal are used to transmit the same message of the same device, the first user plane network element is triggered to determine whether the session of the first terminal and the session of the second terminal are registered to the first user plane network element, instead of determining whether the session of the first terminal and the session of the second terminal are registered to the first user plane network element in all cases, which can reduce the signaling overhead of the first user plane network element.

[0017] Secondly, this application provides a communication device that has the functions of the first aspect described above. For example, the communication device includes modules, units, or means corresponding to the operations involved in the first aspect. These modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0018] Thirdly, this application provides a communication device including an interface circuit and one or more processors. The one or more processors are coupled to a memory. The memory stores part or all of the necessary computer program or instructions for implementing the functions described in the first aspect. The one or more processors can execute the computer program or instructions, causing the communication device to implement the methods in any possible design or implementation of the first aspect. The interface circuit is used to implement the communication functions within the communication device and / or the communication functions between the communication device and other devices or components.

[0019] The aforementioned communication device may be a user plane network element, a module (e.g., a circuit, chip, or chip system) within a user plane network element, or a logic node, logic module, or software capable of implementing all or part of the functions of a user plane network element.

[0020] Fourthly, this application provides a chip (or chip system) including a processor for implementing any of the possible implementation methods of the first aspect above.

[0021] Fifthly, this application provides a computer-readable storage medium storing a computer program or instructions that, when executed, implement any of the possible design methods of the first aspect described above.

[0022] In a sixth aspect, this application provides a computer program product comprising a computer program or instructions that, when executed, implement any of the possible design methods of the first aspect described above.

[0023] In a seventh aspect, this application provides a communication system, including a first user plane network element and a network device. The first user plane network element is configured to determine that a session of a first terminal is registered to the first user plane network element and a session of a second terminal is not registered to the first user plane network element; send a query request to the network device, the query request being used to query whether the session of the second terminal has been registered to the second user plane network element; receive a query response from the network device, the query response being used to indicate that the session of the second terminal has been registered to the second user plane network element; and, based on the query response, send a request message, the request message being used to request the unregistration of the session of the first terminal and the re-registration of the session of the first terminal to the second user plane network element; wherein the first terminal and the second terminal are used to transmit the same packets from the same device, and the second user plane network element is used to forward the received same packets from either the first terminal or the second terminal; the network device is configured to receive the query request from the first user plane network element; and send the query response to the first user plane network element.

[0024] In one possible implementation, the network device is the second user plane network element; or, the network device is the session management network element corresponding to the DNN; wherein, the DNN corresponds to the session of the first terminal and the session of the second terminal.

[0025] In one possible implementation, the first user plane network element is further configured to receive messages from the first terminal and send messages from the first terminal to the second user plane network element.

[0026] In one possible implementation, the first user plane network element is configured to determine that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element, including: determining that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element based on information indicating that the first terminal and the second terminal are used to transmit the same message of the same device. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a service-oriented architecture-based network architecture;

[0028] Figure 2(a) is a schematic diagram of a dual-spin-and-receive scheme;

[0029] Figure 2(b) is another schematic diagram of the dual-launch selective receiver scheme;

[0030] Figure 3 A flowchart illustrating a communication method provided in an embodiment of this application;

[0031] Figure 4 A flowchart illustrating a communication method provided in an embodiment of this application;

[0032] Figure 5 A flowchart illustrating a communication method provided in an embodiment of this application;

[0033] Figure 6 The following is a possible exemplary block diagram of the communication device involved in the embodiments of this application;

[0034] Figure 7 This is a possible exemplary block diagram of the communication device involved in the embodiments of this application. Detailed Implementation

[0035] Figure 1 This is a schematic diagram of a network architecture based on a service-oriented architecture. Figure 1 The network architecture shown may include access network equipment and core network equipment. Terminals access the data network (DN) through the access network equipment and core network equipment. The core network equipment includes, but is not limited to, some or all of the following network elements: authentication server function (AUSF) network element, unified data management (UDM) network element, unified data repository (UDR) network element, network repository function (NRF) network element, network exposure function (NEF) network element, application function (AF) network element, policy control function (PCF) network element, access and mobility management function (AMF) network element, session management function (SMF) network element, and user plane function (UPF) network element.

[0036] It should be noted that the term "network element" can be omitted in the description of the above network elements (such as SMF network elements, UPF network elements, etc.). For example, an SMF network element can be abbreviated as SMF, a UPF network element as UPF, and so on. Furthermore... Figure 1 This abbreviated description is also used in Chinese.

[0037] Access network equipment, sometimes also called RAN nodes, RAN entities, or access nodes, is used to help terminals achieve wireless access.

[0038] In one possible scenario, the access network device can be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a base station in a future mobile communication system, or an access node in a wireless fidelity (WiFi) system. The access network device can be a macro base station, a micro base station, an indoor station, a relay node, or a donor node. Optionally, the access network device can also be a server, a wearable device, a vehicle, or an in-vehicle device. For example, the access network device in vehicle-to-everything (V2X) technology can be a roadside unit (RSU). All or part of the functions of the access network device in this application can also be implemented through software functions running on hardware, or through virtualization functions exemplified on a platform (e.g., a cloud platform). The access network device can also be equipped with communication modules, circuits, or chips that perform corresponding communication functions. The access network device can also be configured with program instructions for performing corresponding communication functions and corresponding program instructions. The access network device in this application may also be a logical node, logical module, or software that can implement all or part of the functions of the access network device.

[0039] In another possible scenario, multiple access network devices collaborate to assist the terminal in achieving wireless access, with each device performing a portion of the base station's functions. For example, the access network devices can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be separate entities or included in the same network element, such as a baseband unit (BBU). The RU can be included in radio frequency equipment or radio frequency units, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0040] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an open radio access network (ORAN) system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through a software module, a hardware module, or a combination of software and hardware modules.

[0041] A terminal can also be called a terminal device, user equipment (UE), mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, smart home devices, transportation vehicles with wireless communication capabilities, communication modules, or customer premises equipment (CPE), etc. The embodiments of this application do not limit the device form of the terminal. Terminals typically contain communication modules, circuits, or chips that perform corresponding communication functions. The terminal can also be configured with program instructions for performing corresponding communication functions.

[0042] Access network devices and terminals can be fixed in location or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed in the air on aircraft, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of the access network devices and terminals.

[0043] The AMF (Automatic Mobility Management) network element includes functions such as performing mobility management or access authentication / authorization. In addition, it is responsible for transmitting user policies between the terminal and the PCF (Programmable Default Function) network element.

[0044] SMF network elements include functions such as performing session management, executing control policies issued by PCF network elements, selecting UPF network elements, or allocating Internet Protocol (IP) addresses for terminals.

[0045] UPF network elements include functions such as user plane data forwarding, session / flow-based billing statistics, and bandwidth limiting.

[0046] UDM network elements include functions such as managing contracted data or authorizing user access.

[0047] UDR includes functions for accessing data of various types, such as contract data, policy data, or application data.

[0048] NEF network elements are used to support the opening of capabilities and events.

[0049] AF (Application Provider) network elements convey application-side requests to the network side, such as Quality of Service (QoS) requirements or user state event subscriptions. AFs can be third-party functional entities or application services deployed by operators, such as IP Multimedia Subsystem (IMS) voice call services. AF network elements include those within the core network (i.e., the operator's AFs) and third-party AFs (such as an enterprise's application server).

[0050] PCF network elements include policy control functions such as billing at the session and service flow levels, QoS bandwidth guarantee and mobility management, or terminal policy decisions.

[0051] NRF network elements can be used to provide network element discovery functionality, providing network element information corresponding to the network element type based on requests from other network elements. NRF network elements also provide network element management services, such as network element registration, updates, deregistration, or network element status subscription and push.

[0052] The AUSF network element is responsible for authenticating users to determine whether to allow users or devices to access the network.

[0053] A Domain Provider (DN) is a network located outside of the carrier's network. A carrier's network can connect to multiple DNs, and various services can be deployed on a DN, providing data and / or voice services to terminals. For example, a DN might be the private network of a smart factory. Sensors installed in the workshop can act as terminals, and a control server for these sensors is deployed within the DN. The control server provides services to the sensors. Sensors can communicate with the control server, receive instructions from it, and transmit the collected sensor data back to the control server accordingly. Another example is a DN serving as an internal office network for a company. Employees' mobile phones or computers can act as terminals, accessing information and data resources within the company's internal office network.

[0054] Figure 1 Nausf, Npcf, Nudr, Nudm, Naf, Namf, Nsmf, Nnef, and Nnrf are the service-based interfaces (SBIs) provided by AUSF, PCF, UDR, UDM, AF, AMF, SMF, NEF, and NRF, respectively, used to invoke the corresponding service-based operations. N1, N2, N3, N4, and N6 are interface sequence numbers, with the following meanings:

[0055] 1) N1: The interface between the AMF network element and the terminal, which can be used to transmit non-access stratum (NAS) signaling (such as QoS rules from the AMF network element) to the terminal.

[0056] 2) N2: The interface between the AMF network element and the access network equipment, which can be used to transmit radio bearer control information from the core network side to the access network equipment.

[0057] 3) N3: The interface between the access network equipment and the UPF network element, mainly used to transmit uplink and downlink user plane data between the access network equipment and the UPF network element.

[0058] 4) N4: The interface between SMF network elements and UPF network elements. It can be used to transmit information between the control plane and the user plane, including the distribution of forwarding rules, QoS rules, traffic statistics rules, etc. from the control plane to the user plane, as well as the reporting of information from the user plane.

[0059] 5) N6: The interface between the UPF network element and the DN, used to transmit uplink and downlink user data streams between the UPF network element and the DN.

[0060] Figure 1In the illustrated architecture, the various network functional elements are connected via a service-oriented bus and interact through service-oriented interfaces. The advantages of a service-oriented bus include improved network flexibility, openness, scalability, and intelligence, enabling support for diverse service scenarios and requirements. The service-oriented bus can be used to transmit various types of data and signaling. For example, it can be used to transmit latency-sensitive real-time signaling (e.g., service-oriented interface call signaling between functional network elements), latency-sensitive real-time data (e.g., real-time AI inference data), and non-real-time data (e.g., offline AI training data). Furthermore, when transmitting this data or signaling, the service-oriented bus couples the data or signaling together; that is, the service-oriented bus can simultaneously transmit real-time signaling, real-time data, and non-real-time data.

[0061] It is understood that the aforementioned network element or function can be a network component in a hardware device, a software function running on dedicated hardware, or a virtualized function exemplified on a platform (e.g., a cloud platform). Optionally, the aforementioned network element or function can be implemented by one device, multiple devices working together, or a functional module within a single device; this application embodiment does not specifically limit this.

[0062] The user plane network element and session management network element in this application can be respectively... Figure 1 The UPF and SMF network elements mentioned above can also be network elements in future communication networks that have the functions of the aforementioned UPF and SMF network elements; this application does not limit this.

[0063] Based on the foregoing description, in a 5G network, in the uplink direction, the industrial gateway performs dual transmission of packets, and the user plane network element selects and receives the same packets. In the downlink direction, the user plane network element performs dual transmission of packets, and the industrial gateway selects and receives the packets. Refer to Figure 2(a), which illustrates the dual transmission and selection scheme. The specific process of dual transmission and selection implemented by the industrial gateway and user plane network element can be found in the foregoing description.

[0064] In this application, the 5G LAN module within the industrial gateway can also be referred to as a terminal.

[0065] As an alternative implementation, the industrial gateway in this application can also be replaced by a dual-transmitter selective receiver switch and two terminals, as shown in Figure 2(b). The dual-transmitter selective receiver switch is decoupled from the terminals. The dual-transmitter selective receiver switch has message copying function, redundant message selective receiver function and message reassembly function. The two terminals are used to send the same message.

[0066] The two 5G LAN modules in the industrial gateway in Figure 2(a) or the two terminals in Figure 2(b) are also called paired terminals. Paired terminals can provide services to the same industrial equipment in a paired manner. That is, paired terminals transmit the same messages, realizing redundant message transmission.

[0067] To address the technical challenge of ensuring service continuity and the effectiveness of dual-transmission selective reception when only one terminal is registered to a backup user plane network element, this application provides a corresponding solution.

[0068] The communication method and communication device provided in this application will be described below with reference to the accompanying drawings. It is understood that this application uses a first user plane network element, a second user plane network element, and a session management network element as examples of the interactive execution entities, but this application does not limit the specific form of the execution entity. The method executed by the first user plane network element in this application can also be implemented by a module (e.g., a circuit, chip, or chip system) in the first user plane network element, or by a logical node, logical module, or software capable of implementing all or part of the functions of the first user plane network element. Similarly, the method executed by the second user plane network element in this application can also be implemented by a module (e.g., a circuit, chip, or chip system) in the second user plane network element, or by a logical node, logical module, or software capable of implementing all or part of the functions of the second user plane network element. Likewise, the method executed by the session management network element in this application can also be implemented by a module (e.g., a circuit, chip, or chip system) in the session management network element, or by a logical node, logical module, or software capable of implementing all or part of the functions of the session management network element.

[0069] It should be noted that, in this application, "terminal registration to user plane network element" refers to one or more sessions of the terminal registering to the user plane network element. This will be explained uniformly here and will not be elaborated further later.

[0070] Figure 3 This is a flowchart illustrating a communication method provided in an embodiment of this application. The first user plane network element and the second user plane network element are two user plane network elements that serve as backups for each other, with the second user plane network element being the primary user plane network element and the first user plane network element being the backup user plane network element. Alternatively, the first user plane network element and the second user plane network element are not two user plane network elements that serve as backups for each other. However, in a load balancing scenario, if the load on one user plane network element is heavy, some or all of the functions or services on that user plane network element can be switched to the other user plane network element to continue execution.

[0071] The first terminal and the second terminal form a paired terminal, that is, the first terminal and the second terminal are used to transmit the same message of the same device (such as industrial equipment). For example, the first terminal and the second terminal can be different 5G LAN modules in Figure 2(a), or they can be different terminals in Figure 2(b). This application does not limit the specific form of the first terminal and the second terminal.

[0072] Under normal circumstances, the sessions of both the first terminal and the second terminal are registered to the second user plane network element, which then implements the dual-transmission selection function. When the second user plane network element is offline (e.g., due to a fault) or under heavy load, the sessions of both the first terminal and the second terminal are registered to the first user plane network element, which then implements the dual-transmission selection function.

[0073] This application considers the following scenario: Due to a fault or excessive load on the second user plane network element, the first terminal's session is registered to the first user plane network element, but the second terminal's session is not registered to the first user plane network element. Furthermore, the second terminal's session may or may not be registered to the second user plane network element. After the second user plane network element recovers from the fault or its load returns to normal, the following can be executed: Figure 3 Method implementation examples.

[0074] refer to Figure 3 The method includes the following steps:

[0075] Step 301: The first user plane network element determines that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element, and sends a query request.

[0076] This query request is used to check whether the session of the second terminal has been registered to the second user plane network element.

[0077] As one implementation method, the first user plane network element triggers a determination, based on information indicating that the first terminal and the second terminal are transmitting the same message from the same device, whether the sessions of the first terminal and the second terminal are registered with the first user plane network element. When the first user plane network element determines that only one terminal (e.g., the first terminal) has a session registered with the first user plane network element, and the session of the other terminal (e.g., the second terminal) is not registered with the first user plane network element, the first user plane network element sends the aforementioned query request.

[0078] The information used to indicate that the first terminal and the second terminal are used to transmit the same message from the same device can be local configuration information configured on the first user plane network element, or it can be indication information received from other network elements (such as session management network elements). This application does not limit this.

[0079] In one implementation method, the first user plane network element sends a query request to the second user plane network element, which then queries whether the session of the second terminal has been registered with the second user plane network element.

[0080] In another implementation, the first user plane network element sends a query request to the session management network element corresponding to the DNN. The session management network element then queries whether the second terminal's session has been registered with the second user plane network element. Here, the DNN corresponds to both the first and second terminal's sessions; that is, the first and second terminals use the same DNN during session establishment. The number of session management network elements corresponding to this DNN may be one or more. These include session management network elements providing services to both the first and second terminals. Furthermore, the session management network element providing services to the first and second terminals may be the same or different session management network elements.

[0081] Step 302: The first user plane network element receives the query response.

[0082] The query response is used to indicate whether the second terminal's session has been registered with the second user plane network element or not.

[0083] In one implementation, if the query request is sent to a second user plane network element, then the query response comes from the second user plane network element.

[0084] In another implementation, if the query request is sent to the session management network element corresponding to the DNN, then the query response comes from the session management network element corresponding to the DNN. Furthermore, if there are multiple session management network elements corresponding to the DNN, then at least one session management network element sends a query response to indicate that the second terminal's session has been registered with the second user plane network element.

[0085] This application specifies the particular indication of the query response, and some examples are given below.

[0086] For example, if the content in the query response is empty, it means that the second terminal's session has not been registered with the second user plane network element.

[0087] For example, if the query response only carries a pair identifier, it means that the second terminal's session has not been registered with the second user plane network element.

[0088] For example, if the query response only carries a DNN, it means that the second terminal's session has not been registered with the second user plane network element.

[0089] For example, if the query response carries a pair identifier and the identifier of the second terminal, it indicates that the session of the second terminal has been registered with the second user plane network element.

[0090] For example, if the query response carries the identifiers of the DNN and the second terminal, it indicates that the session of the second terminal has been registered with the second user plane network element.

[0091] For example, if the query response carries a pairing identifier, the identifier of the second terminal, and indication information, then the indication information is used to indicate that the session of the second terminal has been registered to the second user plane network element, or to indicate that the session of the second terminal has not been registered to the second user plane network element.

[0092] For example, if the query response carries the DNN, the identifier of the second terminal, and indication information, then the indication information is used to indicate whether the session of the second terminal has been registered with the second user plane network element, or to indicate whether the session of the second terminal has not been registered with the second user plane network element.

[0093] In the examples above, the pairing identifier is used to indicate that the first terminal and the second terminal form a pair of terminals, and the DNN corresponds to the session of the first terminal and the session of the second terminal.

[0094] Step 303: The first user plane network element sends a request message based on the query response.

[0095] When the query response indicates that the second terminal's session has been registered with the second user plane network element, the first user plane network element sends a request message to the session management network element corresponding to the first user plane network element. This request message requests to deregister (or deactivate) the first terminal's session and reregister the first terminal's session with the second user plane network element. That is, the session management network element first deregisters (or deactivates) the first terminal's session from the first user plane network element, and then reregisters the first terminal's session with the second user plane network element. After reregistering the first terminal's session with the second user plane network element, both the first terminal's session and the second terminal's session are registered with the second user plane network element, thus enabling the second user plane network element to implement the dual-transmit / selective-receive function.

[0096] When the query response is used to indicate that the second terminal's session is not registered with the second user plane network element, the first user plane network element does not send the aforementioned request message.

[0097] In one implementation, in step 301 above, when the first user plane network element determines that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element, if the first user plane network element receives a message from the first terminal, the first user plane network element forwards the received message from the first terminal to the second user plane network element. Furthermore, before the first terminal's session is re-registered to the second user plane network element, whenever the first user plane network element receives a message from the first terminal, it forwards the received message from the first terminal to the second user plane network element. After receiving the message from the first terminal from the first user plane network element, the second user plane network element handles it differently depending on the situation. In one scenario, if the second terminal's session has already been registered to the second user plane network element, and the second terminal also sends the same message to the second user plane network element, the second user plane network element, based on the dual-transmit / selective-receive function, chooses to forward either the message from the first terminal or the message from the second terminal to the application server. In another scenario, if the second terminal's session is not registered with the second user plane network element, it indicates that the second user plane network element will not receive the same message from the second terminal. Therefore, the second user plane network element forwards the message from the first terminal received from the first user plane network element to the application server. Based on this implementation method, service continuity can be guaranteed.

[0098] In one implementation, before the first terminal session is deregistered from the first user plane network element, the query request in step 302 can be sent periodically. That is, the first user plane network element periodically queries whether the second terminal session has been registered with the second user plane network element to determine whether to request to register (or deactivate) the first terminal session and re-register the first terminal session with the second user plane network element.

[0099] Based on the above scheme, when only one terminal (i.e., the first terminal) in the paired terminals has its session registered with the first user plane network element, after the first user plane network element receives a message from the first terminal, it forwards the message to the second user plane network element, which then forwards it, thus preventing service interruption. Furthermore, the first user plane network element queries the second user plane network element to check if the second terminal's session has already been registered with it. If it confirms that the second terminal's session has been registered with the second user plane network element, it requests to register the first terminal's session with the first user plane network element and re-register the first terminal's session with the second user plane network element. This allows the second user plane network element to receive messages from both the second and first terminals and implement dual-transmission selective reception, eliminating the need for the first user plane network element to forward messages to the second user plane network element. This reduces message transmission latency and ensures the effectiveness of dual-transmission selective reception.

[0100] The reason why the dual-transmission selective reception effect can be guaranteed is as follows: If the session of the first terminal is registered to the first user plane network element and the session of the second terminal is registered to the second user plane network element, the first user plane network element receives packets from the first terminal and forwards them to the second user plane network element. The second user plane network element receives the same packets from the second terminal. Then, the second user plane network element selectively receives the same packets sent by the first and second terminals, that is, it forwards the first received packet to the application server. Since the packets of the first terminal received by the second user plane network element are all forwarded by the first user plane network element, the latency is greater. This means that the second user plane network element may always receive packets from the second terminal first and then receive the same packets from the first terminal from the first user plane network element. Therefore, the second user plane network element always forwards the packets of the second terminal to the application server, resulting in a poor dual-transmission selective reception effect. According to the above-described method embodiments of this application, the sessions of the first terminal and the second terminal are both registered to the second user plane network element. Thus, the second user plane network element directly receives the same packets from the first terminal and the second terminal, and performs dual-transmission and selective reception processing on the same packets. Since the latency of the second user plane network element receiving packets from the first terminal and packets from the second terminal is not much different, the effect of dual-transmission and selective reception can be improved.

[0101] The following section, in conjunction with the accompanying drawings, discusses... Figure 3 The embodiments are described in detail below. Figure 4 Implementation examples and Figure 5 The embodiment is Figure 3 Specific examples of the embodiments are provided below. In the following embodiments, the user plane network element and the session management network element are described using UPF and SMF as examples, respectively. Furthermore, UPF#1 and UPF#2 are examples of the second user plane network element and the first user plane network element in the above embodiments, respectively, and terminal #1 and terminal #2 are examples of the second terminal and the first terminal in the above embodiments, respectively.

[0102] Figure 4 This is a flowchart illustrating a communication method provided in an embodiment of this application. Terminal #1 triggers a session establishment process to register its session with UPF #1, and terminal #2 also triggers a session establishment process to register its session with UPF #1. Terminals #1 and #2 then form a paired terminal network. Both UPF #1 and UPF #2 store pairing information, which is used to indicate that terminals #1 and #2 form a paired terminal network.

[0103] At some point, due to UPF#1 going offline or being under heavy load, terminal #2's session re-registered with UPF#2, but terminal #1's session failed to register successfully with UPF#2. Afterwards, UPF#1 came back online or its load returned to normal. At this point, terminal #2's session is registered with UPF#2, while terminal #1's session is not registered with UPF#2. Furthermore, terminal #1's session may or may not be registered with UPF#1.

[0104] The method includes the following steps:

[0105] Step 401: UPF#2 determines that only the session of terminal #2 is registered to UPF#2 among the paired terminals.

[0106] In step 402, if UPF#2 receives a message from terminal #2, it forwards the message to UPF#1. Accordingly, UPF#1 receives the message.

[0107] Step 403: UPF#1 performs dual transmission and reception based on the message received from UPF#2.

[0108] There are two scenarios here, which will be explained below.

[0109] In the first scenario, if terminal #1's session is registered with UPF #1, then terminal #1 will send messages to UPF #1. Furthermore, the message received by UPF #1 from UPF #2 is the same as the message received from terminal #1. Therefore, UPF #1 uses the dual-transmit / selective-receive function for message forwarding. For example, if UPF #1 first receives message #1 from UPF #2, it forwards message #1 to the application server. If it subsequently receives message #1 from terminal #1 again, it discards that message.

[0110] The second scenario is that terminal #1's session is not registered with UPF #1. In this case, terminal #1 will not send messages to UPF #1. After receiving the message from UPF #2, UPF #1 will forward the message to the application server. In this scenario, selective reception is not implemented; that is, UPF #1 does not receive redundant messages but only receives one message.

[0111] In step 404, UPF#2 periodically sends query requests to UPF#1. Correspondingly, UPF#1 receives the query requests.

[0112] This query request is used to check whether terminal #1 in the paired terminals has been registered to UPF #1.

[0113] The query request includes a pair identifier, or a pair identifier and the identifier of terminal #1, or a DNN and the identifier of terminal #1. The pair identifier indicates that terminal #1 and terminal #2 form a pair of terminals. The DNN is the DNN corresponding to the session of terminal #2, and if terminal #1 registers with UPF #1 through a session establishment procedure, then the session of terminal #1 also corresponds to this DNN.

[0114] In step 405, UPF#1 sends a query response to UPF#2. Correspondingly, UPF#2 receives the query response.

[0115] The query response is used to indicate whether terminal #1 in the paired terminals has been registered to UPF#1, or to indicate whether terminal #1 in the paired terminals has not been registered to UPF#1.

[0116] This application specifies the particular indication of the query response, and some examples are given below.

[0117] For example, if the query response is empty, it means that the session of terminal #1 in the paired terminals has not been registered with UPF #1.

[0118] For example, if the query response only carries a pair identifier, it means that the session of terminal #1 in the pair is not registered to UPF #1.

[0119] For example, if the query response only carries the DNN, it means that the session of terminal #1 in the paired terminals has not been registered to UPF #1.

[0120] For example, if the query response carries the pair identifier and the identifier of terminal #1, it means that the session of terminal #1 in the pair has been registered with UPF #1.

[0121] For example, if the query response carries the identifiers of DNN and terminal #1, it means that the session of terminal #1 in the paired terminals has been registered with UPF #1.

[0122] For example, if the query response carries a pair identifier, the identifier of terminal #1, and indication information, then the indication information is used to indicate that the session of terminal #1 in the pair has been registered to UPF#1, or to indicate that the session of terminal #1 in the pair has not been registered to UPF#1.

[0123] For example, if the query response carries the identifier and indication information of DNN, terminal #1, then the indication information is used to indicate that the session of terminal #1 in the paired terminals has been registered to UPF#1, or to indicate that the session of terminal #1 in the paired terminals has not been registered to UPF#1.

[0124] Step 406: If the session of terminal #1 in the paired terminals has already been registered with UPF#1, then UPF#2 sends a request message to SMF. Accordingly, SMF receives the request message.

[0125] This request message is used to request SMF to deregister the session of terminal #2 and reregister the session of terminal #2 to UPF #1. Here, "deregister" can also be called "deactivate", and "reregister" can also be called "reactivate".

[0126] For example, the request message could be a packet forwarding control protocol (PFCP) report request message.

[0127] In step 407, SMF sends a response message to UPF#2. UPF#2 then receives the response message.

[0128] This response message is a response to the aforementioned request message, indicating that the aforementioned request message has been received, or that the deregistration and reregistration process of the terminal #2 session has been triggered.

[0129] For example, the request message could be a PFCP report response message.

[0130] Step 408, SMF initiates the deregistration process for the session of terminal #2.

[0131] After completing the deregistration process, the session of terminal #2 will register or deactivate from UPF #2.

[0132] Step 409: SMF initiates the re-registration process for the session of terminal #2.

[0133] After completing the re-registration process, the session of terminal #2 is registered to UPF#1, so that the sessions of terminal #1 and terminal #2 are both registered to the same UPF, namely UPF#1, and the dual-transmit and selective-receive function is subsequently implemented by UPF#1.

[0134] It should be noted that after step 405 above, if UPF#2 determines that the session of terminal #1 in the paired terminals is not registered with UPF#1, then subsequent steps 406 to 409 will not be executed. Furthermore, when UPF#2 receives a message from terminal #2, it will still execute the message sending according to the methods described in steps 401 to 403 above.

[0135] Based on the above scheme, when only terminal #2's session is registered with UPF#2 among the paired terminals, UPF#2, upon receiving a message from terminal #2, forwards the message to UPF#1, which then forwards it, thus preventing service interruption. Furthermore, UPF#2 periodically queries UPF#1 to check if terminal #1's session has been registered with UPF#1. If it confirms that terminal #1's session is registered with UPF#1, it requests SMF to register terminal #2's session on UPF#2 and re-register it with UPF#1. This allows UPF#1 to receive messages from both terminal #1 and terminal #2, enabling dual-transmission selective reception. This eliminates the need for UPF#2 to forward messages to UPF#1, reducing message transmission latency and ensuring the effectiveness of dual-transmission selective reception.

[0136] Figure 5 This is a flowchart illustrating a communication method provided in an embodiment of this application. Terminal #1 triggers a session establishment process to register its session with UPF #1, and terminal #2 also triggers a session establishment process to register its session with UPF #1. Terminals #1 and #2 then form a paired terminal network. Both UPF #1 and UPF #2 store pairing information, which is used to indicate that terminals #1 and #2 form a paired terminal network.

[0137] At some point, due to UPF#1 going offline or being under heavy load, terminal #2's session re-registered with UPF#2, but terminal #1's session failed to register successfully with UPF#2. Afterwards, UPF#1 came back online or its load returned to normal. At this point, terminal #2's session is registered with UPF#2, while terminal #1's session is not registered with UPF#2. Furthermore, terminal #1's session may or may not be registered with UPF#1.

[0138] The method includes the following steps:

[0139] Steps 501 to 503 are the same as described above. Figure 4 Steps 401 to 403 in the embodiments.

[0140] In step 504, UPF#2 periodically sends query requests to SMF. Correspondingly, SMF receives the query requests.

[0141] This query request is used to check whether terminal #1 in the paired terminals has been registered to UPF #1.

[0142] The query request includes a pair identifier, or a pair identifier and the identifier of terminal #1, or a DNN and the identifier of terminal #1. The pair identifier indicates that terminal #1 and terminal #2 form a pair of terminals. The DNN is the DNN corresponding to the session of terminal #2, and if terminal #1 registers with UPF #1 through a session establishment procedure, then the session of terminal #1 also corresponds to this DNN.

[0143] Here, SMF refers to the SMF corresponding to DNN, and the number of SMFs is one or more.

[0144] In step 505, SMF sends a query response to UPF#2. Correspondingly, UPF#2 receives the query response.

[0145] The query response is used to indicate whether terminal #1 in the paired terminals has been registered to UPF#1, or to indicate whether terminal #1 in the paired terminals has not been registered to UPF#1.

[0146] This application specifies the particular indication of the query response, and some examples are given below.

[0147] For example, if the query response is empty, it means that the session of terminal #1 in the paired terminals has not been registered with UPF #1.

[0148] For example, if the query response only carries a pair identifier, it means that the session of terminal #1 in the pair is not registered to UPF #1.

[0149] For example, if the query response only carries the DNN, it means that the session of terminal #1 in the paired terminals has not been registered to UPF #1.

[0150] For example, if the query response carries the pair identifier and the identifier of terminal #1, it means that the session of terminal #1 in the pair has been registered with UPF #1.

[0151] For example, if the query response carries the identifiers of DNN and terminal #1, it means that the session of terminal #1 in the paired terminals has been registered with UPF #1.

[0152] For example, if the query response carries a pair identifier, the identifier of terminal #1, and indication information, then the indication information is used to indicate that the session of terminal #1 in the pair has been registered to UPF#1, or to indicate that the session of terminal #1 in the pair has not been registered to UPF#1.

[0153] For example, if the query response carries the identifier and indication information of DNN, terminal #1, then the indication information is used to indicate that the session of terminal #1 in the paired terminals has been registered to UPF#1, or to indicate that the session of terminal #1 in the paired terminals has not been registered to UPF#1.

[0154] Steps 506 to 509 are the same as described above. Figure 4 Steps 406 to 409 in the embodiments.

[0155] It should be noted that after step 505 above, if UPF#2 determines that the session of terminal #1 in the paired terminals is not registered with UPF#1, then subsequent steps 506 to 509 will not be executed. Furthermore, when UPF#2 receives a message from terminal #2, it will still execute the message sending according to the methods described in steps 501 to 503 above.

[0156] Based on the above scheme, when only terminal #2's session is registered with UPF#2 among the paired terminals, UPF#2, upon receiving a message from terminal #2, forwards the message to UPF#1, which then forwards it, thus preventing service interruption. Furthermore, UPF#2 periodically queries SMF to check if terminal #1's session has been registered with UPF#1. If it confirms that terminal #1's session is registered with UPF#1, it requests SMF to register terminal #2's session on UPF#2 and re-register it with UPF#1. This allows UPF#1 to receive messages from both terminal #1 and terminal #2, enabling dual-transmission selective reception. This eliminates the need for UPF#2 to forward messages to UPF#1, reducing message transmission latency and ensuring the effectiveness of dual-transmission selective reception.

[0157] Figure 6 A possible exemplary block diagram of the communication device involved in the embodiments of this application is shown. Figure 6 The communication device 600 shown may include modules or units for implementing the methods described in the embodiments above. In one possible design, the communication device 600 includes a processing unit 602 and a communication unit 603. Optionally, the communication device 600 may further include a storage unit 601 for storing device program code and / or data.

[0158] The communication device 600 can be a network-side device in the above embodiments, such as a network-side access network device, a module (e.g., circuit, chip or chip system) in the access network device, or a logic node, logic module or software that can implement all or part of the functions of the access network device.

[0159] For example, in one embodiment, processing unit 602 is configured to determine that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element; send a query request through communication unit 603, the query request being used to query whether the session of the second terminal has been registered to the second user plane network element; receive a query response through communication unit 603, the query response being used to indicate that the session of the second terminal has been registered to the second user plane network element; and, according to the query response, send a request message through communication unit 603, the request message being used to request to deregister the session of the first terminal and to reregister the session of the first terminal to the second user plane network element; wherein, the first terminal and the second terminal are used to transmit the same message from the same device, and the second user plane network element is used to forward the received same message from the first terminal or the second terminal.

[0160] In one possible implementation, the processing unit 602 is configured to send a query request via the communication unit 603, including: sending the query request to the second user plane network element via the communication unit 603; correspondingly, the processing unit 602 is configured to receive a query response via the communication unit 603, including: receiving the query response from the second user plane network element via the communication unit 603.

[0161] In one possible implementation, the processing unit 602 is configured to send a query request via the communication unit 603, including: sending the query request to the session management network element corresponding to the DNN via the communication unit 603; wherein the DNN corresponds to the session of the first terminal and the session of the second terminal; correspondingly, the processing unit 602 is configured to receive a query response via the communication unit 603, including: receiving the query response from the session management network element via the communication unit 603.

[0162] In one possible implementation, the processing unit 602 is further configured to receive a message from the first terminal via the communication unit 603; and to send the message from the first terminal to the second user plane network element.

[0163] In one possible implementation, the processing unit 602 is configured to determine that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element, including: determining that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element based on information indicating that the first terminal and the second terminal are used to transmit the same message for the same device.

[0164] It is understood that the division of units in the above-described device is merely a logical functional division. One function can correspond to one functional unit, or two or more functions can be integrated into one functional unit. In actual implementation, all or some units can be integrated onto a single physical entity, or distributed across different physical entities. Furthermore, the aforementioned functional units can be implemented in hardware, software, or a combination of both. Whether a function is executed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for specific applications, but such implementations should not be considered beyond the scope of this application.

[0165] In one example, the functional unit in any of the above devices may be one or more integrated circuits configured to implement the above methods, such as: one or more application-specific integrated circuits (ASICs), or one or more central processing units (CPUs), one or more microcontroller units (MCUs), one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms.

[0166] In one example, storage unit 601 may include random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory and / or registers, etc.

[0167] Figure 7 A possible exemplary block diagram of the communication device involved in the embodiments of this application is shown. Figure 7 The communication device 700 shown includes a processor 710 and an interface circuit 720. The processor 710 and the interface circuit 720 are coupled to each other. It is understood that the interface circuit 720 can be a transceiver or an input / output interface. Optionally, the communication device 700 may also include a memory 730 for storing instructions executed by the processor 710, or storing input data required for the processor 710 to execute instructions, or storing data generated after the processor 710 executes instructions.

[0168] When the communication device 700 is used to implement the above method embodiment, the processor 710 is used to implement the function of the processing unit 602, and the interface circuit 720 is used to implement the function of the communication unit 603.

[0169] It is understood that the processor in the embodiments of this application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

[0170] This application provides a chip (or chip system) including a processor for implementing any of the above-described method embodiments.

[0171] This application provides a computer-readable storage medium storing a computer program or instructions that, when executed, implement any of the above-described method embodiments.

[0172] This application provides a computer program product, which includes a computer program or instructions that, when executed, implement any of the above-described method embodiments.

[0173] This application provides a communication system, including a second user plane network element and a network device in the above method embodiments. The network device may be a first user plane network element or a session management network element corresponding to a DNN in the above method embodiments.

[0174] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, compact disc read-only memory (CD-ROM), or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Furthermore, the ASIC can reside in a first network element or a store-and-forward terrestrial function network element. Alternatively, the processor and storage medium can exist as discrete components in access network equipment or terminal equipment.

[0175] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. A computer program is a set of instructions that directs each step of an action of an electronic computer or other device with message processing capabilities. It is typically written in a programming language and runs on a target architecture. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed, in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be volatile or non-volatile, or it can include both types of storage media.

[0176] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0177] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0178] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

[0179] The terms "system" and "network" in this application embodiment are used interchangeably. "At least one" refers to one or more, and "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of A, B, or C" includes A, B, C, AB, AC, BC, or ABC; "at least one of A, B, and C" can also be understood as including A, B, C, AB, AC, BC, or ABC. Furthermore, unless otherwise specified, the ordinal numbers such as "first" and "second" mentioned in this application embodiment are used to distinguish multiple objects and are not used to limit the order, sequence, priority, or importance of multiple objects.

[0180] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0181] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0182] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0183] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0184] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method, characterized in that, Applied to a first user plane network element, the method includes: If it is determined that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element, a query request is sent. The query request is used to query whether the session of the second terminal has been registered to the second user plane network element. Receive a query response, the query response being used to indicate that the session of the second terminal has been registered to the second user plane network element; Based on the query response, a request message is sent, which is used to request to register the session of the first terminal and to re-register the session of the first terminal to the second user plane network element. The first terminal and the second terminal are used to transmit the same message from the same device, and the second user plane network element is used to forward the same message received from the first terminal or the second terminal.

2. The method as described in claim 1, characterized in that, Sending the query request includes: sending the query request to the second user plane network element; Accordingly, receiving the query response includes receiving the query response from the second user plane network element.

3. The method as described in claim 1, characterized in that, Sending the query request includes: sending the query request to the session management network element corresponding to the data network name (DNN); wherein the DNN corresponds to the session of the first terminal and the session of the second terminal; Accordingly, receiving the query response includes receiving the query response from the session management network element.

4. The method according to any one of claims 1 to 3, characterized in that, Also includes: Receive messages from the first terminal; The message from the first terminal is sent to the second user plane network element.

5. The method according to any one of claims 1 to 4, characterized in that, The query response carries a pair identifier; or... The query response carries a pair identifier and the identifier of the second terminal; or, The query response carries the identifiers of the DNN and the second terminal; or, The query response carries a pairing identifier, the identifier of the second terminal, and indication information; or, The query response carries the DNN, the identifier of the second terminal, and indication information; The pairing identifier is used to indicate that the first terminal and the second terminal form a pair of terminals, the pair of terminals are used to transmit the same message from the same device, the DNN corresponds to the session of the first terminal and the session of the second terminal, and the indication information is used to indicate that the session of the second terminal has been registered to the second user plane network element.

6. The method according to any one of claims 1 to 5, characterized in that, The step of determining that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element includes: Based on the information used to indicate that the first terminal and the second terminal are transmitting the same message for the same device, it is determined that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element.

7. A communication device, characterized in that, Includes a module for performing the method according to any one of claims 1 to 6.

8. A computer program product, characterized in that, The computer program product includes instructions that, when executed, implement the method of any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions, which, when executed, implement the method described in any one of claims 1 to 6.

10. A chip, characterized in that, The chip includes a processor for implementing the method of any one of claims 1 to 6.

11. A communication system, characterized in that, include: A first user plane network element is configured to determine that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element, and to send a query request to the network device, wherein the query request is used to query whether the session of the second terminal has been registered to the second user plane network element; and to receive a query response from the network device, wherein the query response is used to indicate that the session of the second terminal has been registered to the second user plane network element. And according to the query response, a request message is sent, the request message being used to request to register the session of the first terminal and to re-register the session of the first terminal to the second user plane network element; wherein, the first terminal and the second terminal are used to transmit the same message from the same device, and the second user plane network element is used to forward the same message received from the first terminal or the second terminal. The network device is configured to receive the query request from the first user plane network element and send the query response to the first user plane network element.

12. The system as claimed in claim 11, characterized in that, The network device is the second user plane network element; or... The network device is the session management network element corresponding to the data network name (DNN); wherein, the DNN corresponds to the session of the first terminal and the session of the second terminal.

13. The system as described in claim 11 or 12, characterized in that, The first user plane network element is further configured to receive messages from the first terminal and to send messages from the first terminal to the second user plane network element.

14. The system as claimed in any one of claims 11 to 13, characterized in that, The first user plane network element is configured to determine that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element, including: determining, based on information indicating that the first terminal and the second terminal are used to transmit the same message for the same device, that the session of the first terminal is registered to the first user plane network element and the session of the second terminal is not registered to the first user plane network element.

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