Method and apparatus for voice communication

Abstract

The application provides a voice communication method, which comprises the following steps: a first network element acquires a first Internet Protocol (IP) address of a terminal registered in a first network; the first network element sends first information to a second network element, wherein the first information comprises the first IP address, the first IP address is an IP address related to a first connection of the terminal device, and the first connection is used for accessing an Internet Protocol Multimedia Subsystem (IMS); the first network element receives first indication information from the second network element, wherein the first indication information is used for indicating that the terminal is switched or redirected from the first network to a second network, and the second network provides the IMS for the terminal; the first network element acquires a second IP address of the terminal registered in the second network; and the first network element establishes a second connection according to the first indication information and the second IP address of the terminal, and the second connection is used for accessing the IMS by the terminal device. The method makes the terminal obtain the IMS service and guarantees the service experience of the user.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to voice communication methods and apparatus. Background Technology

[0002] Currently, mobile networks that terminal devices can access include 2G, 3G, 4G, and 5G networks, which provide data transmission channels for user-defined communication (UE) services such as voice calls, video calls, and web browsing. The Internet Protocol Multimedia Subsystem (IMS) is a new form of multimedia service that can meet the increasingly novel and diverse multimedia service needs of today's terminal customers. The IMS network is an essential Internet protocol for Long Term Evolution (LTE) to achieve the convergence of voice and multimedia data.

[0003] A standalone non-public network (SNPN) is deployed independently and does not rely on a public land mobile network (PLMN). Currently, the PLMN's IMS can provide IMS services to terminals accessing the SNPN.

[0004] However, since SNPN does not provide IMS voice capabilities, how SNPN can use PLMN's IMS to provide IMS services to terminal devices has become a technical problem that needs to be solved. Summary of the Invention

[0005] This application provides a voice communication method and apparatus that enables SNPN to provide IMS services to terminals using PLMN's IMS, thereby ensuring the user's service experience.

[0006] In a first aspect, a voice communication method is provided, comprising: a first network element obtaining a first Internet Protocol (IP) address of a terminal device registered in a first network; the first network element sending first information to a second network element, the first information including a first IP address, the first IP address being an IP address associated with a first connection of the terminal device, the first connection being used to access an Internet Protocol Multimedia Subsystem (IMS); the first network element receiving first indication information from the second network element, the first indication information being used to instruct the terminal device to switch or redirect from the first network to the second network, the second network providing IMS services to the terminal device through the IMS; the first network element obtaining a second IP address of the terminal device registered in the second network; and the first network element establishing a second connection based on the first indication information and the second IP address of the terminal device, the second connection being used by the terminal device to access the IMS.

[0007] It should be understood that in this application, the first connection and the second connection support communication between the terminal device and the same communication peer. For example, the first connection and the second connection have the same target port or target IP address, where the target port or target IP address refers to the IP address and port of the communication peer of the terminal device. In this application, the first connection can be used to carry multimedia IP streams.

[0008] Based on the above technical solution, when the first network does not provide IMS voice capability, the first network can switch or redirect the terminal device to the second network, thereby using the IMS of the second network to provide IMS service to the terminal device; the terminal device makes an IMS call between the first network and the communication peer to trigger the establishment of the first connection, and the first network element establishes a second connection for the terminal device according to the first indication information, without having to wait for the terminal device to switch or redirect to the second network and make another IMS call with the communication peer to trigger the establishment of the second connection, saving signaling and ensuring the user's service experience.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the first network element establishes a second connection based on the first indication information and the second IP address of the terminal device, including: the first network element saving the status information of the terminal device based on the first indication information, the status information including the second indication information, the second indication information being used to indicate that the first network element establishes the second connection after the terminal device switches or is redirected to the second network; when the first network element obtains the second IP address of the terminal device registered in the second network, the first network element establishes the second connection based on the second indication information.

[0010] Based on the above technical solutions, when a terminal device switches or is redirected to the second network, the first network element can re-establish the second connection to provide IMS services to the terminal device and ensure the user's business experience.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the first network element obtains the second IP address of the terminal device registered in the second network, including: the first network element obtains the second IP address of the terminal device through a registration message, or; the first network element obtains the second IP address of the terminal device through a terminal device address change message.

[0012] Based on the above technical solutions, the first network element can flexibly obtain the new IP address of the terminal device in order to re-establish the IMS connection later.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the first network is an independently deployed, non-public network.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the second network is a public land mobile network.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, the first network element is the proxy call control function network element in the IMS network.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the second network element is a policy control network element.

[0017] Secondly, a voice communication method is provided, comprising: a third network element determining third indication information based on a first condition, the third indication information being used to indicate whether a first network supports Internet Protocol Multimedia Subsystem (IMS) service, the first condition including at least one of the following: whether the first network supports Home Router (HR) sessions with a second network; whether the first network and the second network share common session management function network elements and / or common user plane function network elements; whether the first network and the second network share common proxy call control function network elements; and whether there is a connection between the IMS of the first network and the second network, wherein the second network provides the IMS service to terminal devices registered in the first network through the IMS; and the third network element sending the third indication information to the terminal devices.

[0018] Based on the above technical solution, the third network element determines whether the first network supports Internet Protocol Multimedia Subsystem (IMS) service through the first condition. Depending on the different determination results, the UE can use different methods to obtain IMS service, thus ensuring the user's service experience.

[0019] In this application, whether the first network supports Internet Protocol Multimedia Subsystem (IMS) services includes whether the first network supports providing IMS services to UEs accessing the first network, or whether the first network supports using the IMS of the second network to provide IMS services to UEs accessing the first network.

[0020] In conjunction with the second aspect, in some implementations of the second aspect, there is a connection between the IMS of the first network and the second network, and the first condition further includes: whether the Service Level Agreement (SLA) between the first network and the second network supports the IMS service.

[0021] In conjunction with the second aspect, in some implementations of the second aspect, the first network is an independently deployed, non-public network.

[0022] In conjunction with the second aspect, in some implementations of the second aspect, the second network is a public land mobile network.

[0023] In conjunction with the second aspect, in some implementations of the second aspect, the third network element is an access and mobility management function network element.

[0024] Thirdly, a voice communication method is provided, comprising: a terminal device receiving third indication information from a third network element in a first network, the third indication information indicating that the first network does not support Internet Protocol Multimedia Subsystem (IMS) service; the terminal device determining a second network according to configuration information, the second network providing IMS service to the terminal device through the IMS, the configuration information including the priority of candidate networks, wherein when a first candidate network is connected to the IMS of the first network and the first candidate network provides the IMS service to the terminal device, the priority of the first candidate network in the configuration information is higher than the priority of other candidate networks.

[0025] Based on the above technical solutions, when the third network element determines that the first network does not support Internet Protocol Multimedia Subsystem (IMS) services, the terminal device can select a network that supports IMS services through network reselection, thereby ensuring the user's service experience.

[0026] In conjunction with the third aspect, in some implementations of the third aspect, the method further includes: the terminal device updating configuration information, the configuration information including the network identifier of the first network and / or the third indication information.

[0027] In conjunction with the third aspect, in some implementations of the third aspect, the configuration information further includes the network identifier of the candidate network and / or fourth indication information, wherein the fourth indication information is used to indicate whether the candidate network supports IMS services.

[0028] Based on the above technical solutions, the terminal device can determine the candidate network that supports IMS services according to the fourth indication information.

[0029] In conjunction with the third aspect, in some implementations of the third aspect, the first network is an independently deployed, non-public network.

[0030] In conjunction with the third aspect, in some implementations of the third aspect, the second network is a public land mobile network.

[0031] In conjunction with the third aspect, in some implementations of the third aspect, the third network element is an access and mobility management function network element.

[0032] Fourthly, a voice communication method is provided, comprising: a unified data management network element receiving second information from a session management function network element in a first network, the second information including address information of a proxy call control function network element in an Internet Protocol Multimedia Subsystem (IMS); the unified data management network element receiving a first request from a session management function network element in a second network, the second network providing IMS services to terminal devices registered in the first network through the IMS; and the unified data management network element sending a first response to a session management function network element in the second network, the first response including the address information of the proxy call control function network element.

[0033] Based on the above technical solution, the unified data management network element can send the address information of the proxy call control function network element to the session management function network element in the second network. When the terminal device switches or is redirected to the second network, the session management function network element can obtain the address information of the proxy call control function network element and send it to the terminal device, so that the terminal device accessing the second network can reconnect to the proxy call control function network element and ultimately enable the proxy call control function network element to re-establish the IMS service.

[0034] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the first network is an independently deployed, non-public network.

[0035] In conjunction with the fourth aspect, in some implementations of the fourth aspect, the second network is a public land mobile network.

[0036] Fifthly, a voice communication device is provided, the device being used to perform the voice communication method in the first aspect or any possible implementation thereof.

[0037] In a sixth aspect, a voice communication apparatus is provided, the apparatus being used to perform the voice communication method in the second aspect or any possible implementation thereof.

[0038] In a seventh aspect, a voice communication apparatus is provided, the apparatus being used to perform the voice communication method in the third aspect or any possible implementation thereof.

[0039] Eighthly, a voice communication apparatus is provided, the apparatus being used to perform the voice communication method in the fourth aspect or any possible implementation thereof.

[0040] Ninthly, embodiments of this application provide a voice communication device, including a transceiver and a processor, wherein the transceiver and the processor are used to implement the voice communication method in the first aspect or any possible implementation of the first aspect.

[0041] In a tenth aspect, embodiments of this application provide a voice communication device, including a transceiver and a processor, wherein the transceiver and the processor are used to implement the voice communication method in the second aspect or any possible implementation of the second aspect.

[0042] Eleventhly, embodiments of this application provide a voice communication device, including a transceiver and a processor, wherein the transceiver and the processor are used to implement the voice communication method in the third aspect or any possible implementation of the third aspect.

[0043] In a twelfth aspect, embodiments of this application provide a voice communication device, including a transceiver and a processor, wherein the transceiver and the processor are used to implement the voice communication method in the fourth aspect or any possible implementation of the fourth aspect.

[0044] In a thirteenth aspect, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive signals through the input circuit and transmit signals through the output circuit, causing an apparatus including the processor to perform the methods of the first to fourth aspects and any possible implementation thereof.

[0045] In specific implementation, the processor can be one or more chips, the input circuit can be input pins, the output circuit can be output pins, and the processing circuit can be transistors, gate circuits, flip-flops, and various logic circuits. The input signal received by the input circuit can be received and input by, for example, but not limited to, a transceiver, and the signal output by the output circuit can be, for example, but not limited to, output to and transmitted by a transmitter. Furthermore, the input circuit and the output circuit can be the same circuit, which is used as both the input circuit and the output circuit at different times. This application does not limit the specific implementation of the processor and various circuits.

[0046] In a fourteenth aspect, a voice communication device is provided, including a processor and a memory. The processor is configured to read instructions stored in the memory and to receive signals via a transceiver and transmit signals via a transmitter to execute methods of the first to fourth aspects and any possible implementation thereof.

[0047] The processor may be one or more, and the memory may be one or more.

[0048] The memory can be integrated with the processor, or it can be set up separately from the processor.

[0049] In the specific implementation process, the memory can be a non-transitory memory, such as read-only memory (ROM), which can be integrated with the processor on the same chip or set on different chips. The embodiments of this application do not limit the type of memory or the way the memory and processor are set.

[0050] It should be understood that the relevant data interaction process, such as sending indication information, can be the process of the processor outputting indication information, and receiving capability information can be the process of the processor receiving input capability information. Specifically, the data output by the processor can be sent to the transmitter, and the input data received by the processor can come from the transceiver. Here, the transmitter and the transceiver can be collectively referred to as transceivers.

[0051] The voice communication device described in aspect fourteen above can be one or more chips, or a chip system. The processor in this communication device can be implemented in hardware or software. When implemented in hardware, the processor can be a logic circuit, integrated circuit, etc.; when implemented in software, the processor can be a general-purpose processor that reads software code stored in memory. This memory can be integrated into the processor or located outside the processor and exist independently.

[0052] In a fifteenth aspect, a chip is provided, the chip including a processor and a communication interface for communicating with external or internal devices, the processor for performing methods of the first to fourth aspects and any possible implementation thereof.

[0053] Optionally, the chip may further include a memory storing instructions, which the processor executes either the instructions stored in the memory or instructions derived from other instructions. When the instructions are executed, the processor performs the methods of the first to fourth aspects and any of the possible implementations of the first to fourth aspects.

[0054] In a sixteenth aspect, a computer program product is provided, the computer program product comprising: a computer program (also referred to as code or instructions) that, when the computer program is run, causes the methods of the first to fourth aspects and any possible implementation thereof to be performed.

[0055] In a seventeenth aspect, a computer-readable storage medium is provided that stores a computer program (also referred to as code or instructions) that, when run on a computer, causes the computer to perform the methods described in the first to fourth aspects and any possible implementation thereof.

[0056] Eighteenthly, a communication system is provided, including one or more means having functions for implementing the methods and various possible designs of the first to fourth aspects described above. Attached Figure Description

[0057] Figure 1 This is a system architecture diagram applicable to the embodiments of this application.

[0058] Figure 2 This is a system architecture diagram applicable to the embodiments of this application.

[0059] Figure 3 This is a schematic diagram of a scenario applicable to the embodiments of this application.

[0060] Figure 4 This is a schematic flowchart illustrating the voice communication method provided in the embodiments of this application.

[0061] Figure 5 This is a schematic flowchart illustrating the voice communication method provided in the embodiments of this application.

[0062] Figure 6 This is a schematic flowchart illustrating the voice communication method provided in the embodiments of this application.

[0063] Figure 7 This is a schematic flowchart illustrating the voice communication method provided in the embodiments of this application.

[0064] Figure 8 This is a schematic flowchart illustrating the voice communication method provided in the embodiments of this application.

[0065] Figure 9 This is a schematic block diagram of a voice communication device provided in an embodiment of this application.

[0066] Figure 10 This is a schematic block diagram of a voice communication device provided in an embodiment of this application.

[0067] Figure 11 This is a schematic block diagram of a voice communication device provided in an embodiment of this application. Detailed Implementation

[0068] The wireless communication systems applicable to the embodiments of this application include, but are not limited to: Global System for Mobile Communication (GSM) system, Long Term Evolution (LTE) Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD) system, LTE system, LTE-Advanced (LTE-A) system, next-generation communication system (e.g., 5G, 6G communication system), converged system of multiple access systems, or evolved system.

[0069] The technical solutions provided in this application can also be applied to machine-type communication (MTC), Long Term Evolution-machine (LTE-M) technology, device-to-device (D2D) networks, machine-to-machine (M2M) networks, Internet of Things (IoT) networks, or other networks. Among these, IoT networks may include, for example, vehicle-to-everything (V2X) networks. The communication methods in V2X systems are collectively referred to as vehicle-to-X (V2X), where X can represent anything. For example, V2X may include vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, or vehicle-to-network (V2N) communication, etc.

[0070] The terminal devices involved in this application embodiment serve as the entry point for mobile users to interact with the network. They provide basic computing and storage capabilities, display service windows to users, and accept user input. In 5G, terminal devices can employ New Radio (NR) technology to establish signal and data connections with wireless access network (UART) devices, thereby transmitting control signals and service data to the mobile network. The terminal devices involved in this application embodiment can include various access terminals, mobile devices, user terminals, or user equipment with wireless communication capabilities. For example, a terminal device can be a user equipment (UE), such as a mobile phone, tablet, computer with wireless transceiver capabilities, virtual reality (VR) terminal device, augmented reality (AR) terminal device, etc. Terminal devices can also be wireless terminals in industrial control, machine-type communication (MTC) terminals, customer premise equipment (CPE), wireless terminals in self-driving, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices, terminal devices in 5G networks, or terminal devices in future evolved public land mobile networks (PLMNs) or non-public networks (NPNs), etc.

[0071] The wireless access network equipment involved in this application embodiment is similar to a base station in a traditional network. Deployed close to the terminal device, it provides network access functionality to authorized users in a specific area and can determine transmission tunnels of different quality based on user level and service requirements to transmit user data. The wireless access network equipment can manage its own resources, utilize them rationally, provide access services to the terminal device on demand, and is responsible for forwarding control signals and user data between the terminal device and the core network. The wireless access network equipment involved in this application embodiment can be an access device through which a terminal device wirelessly accesses the mobile communication system. This wireless access network equipment can be: a base station, an evolved Node B (eNB), a home base station, an access point (AP) in a wireless fidelity (WiFi) system, a wireless relay node, a wireless backhaul node, a transmission point (TP) or a transmission and reception point (TRP), a macro base station or micro base station, a high-frequency base station, etc. The wireless access network device can also be a next-generation node B (gNB) in an NR system, or it can be a component or part of a base station, such as a central unit (CU), a distributed unit (DU), or a baseband unit (BBU). It should be understood that the specific technology and device form used in the embodiments of this application are not limited. In this application, the wireless access network device is referred to as a network device. Unless otherwise specified, network device refers to wireless access network device. In this application, network device can refer to the network device itself or a chip used in the network device to perform wireless communication processing functions.

[0072] The following is combined with Figure 1 and Figure 2 This application provides a detailed description of the network system architecture involved in its embodiments.

[0073] Figure 1This is a system architecture diagram applicable to the embodiments of this application. As shown in the figure, the system architecture consists of terminal devices, radio access network (RAN), core network, and data network. The terminal devices, RAN, and core network (CN) are the main components of the architecture. The core network is responsible for maintaining the subscription data of the mobile network, managing the network elements of the mobile network, and providing functions such as session management, mobility management, policy management, and security authentication for the terminal devices. When the terminal device attaches, it provides network access authentication; when the terminal device has a service request, it allocates network resources for the terminal device; when the terminal device moves, it updates network resources for the terminal device; when the terminal device is idle, it provides a fast recovery mechanism; when the terminal device detaches, it releases network resources for the terminal device; when the terminal device has service data, it provides data routing functions, such as forwarding uplink data to the data network; or receiving downlink data from the data network and forwarding it to the RAN, thereby sending it to the UE. Logically, the system architecture can be divided into two parts: the user plane and the control plane. The control plane is responsible for the management of the mobile network, and the user plane is responsible for the transmission of service data. Figure 1 In this context, the NG2 reference point is located between the radio access network control plane and the core network control plane, the NG3 reference point is located between the radio access network user plane and the core network user plane, and the NG6 reference point is located between the core network user plane and the data network.

[0074] Figure 2 This is a system architecture diagram applicable to the embodiments of this application. As shown in the figure, the network architecture may specifically include the following network elements:

[0075] 1. Radio Access Network (RAN): An access network that implements access network functions based on wireless communication technology can be called a radio access network. The radio access network manages radio resources, provides access services to terminals, and thus completes the forwarding of control signals and user data between terminals and the core network.

[0076] The wireless access network can be, for example, a base station (BTS) in a Global System for Mobile Communications (GSM) or Code Division Multiple Access (CDMA) system, a base station (nodeB, NB) in a Wideband Code Division Multiple Access (WCDMA) system, an evolved NodeB (eNB or eNodeB) in an LTE system, or a wireless controller in a cloud radio access network (CRAN) scenario. Alternatively, the network device can be a relay station, access point, vehicle-mounted device, wearable device, or network device in a 5G network or a network device in a future evolved PLMN network, etc. The embodiments in this application are not limited to these.

[0077] 2. Authentication server function (AUSF) network element: mainly used for user authentication, etc.

[0078] 3. Access and Mobility Management Function (AMF): Primarily used for mobility management and access management, it can implement functions of the Mobility Management Entity (MME) other than session management, such as lawful access monitoring or access authorization (or authentication). In the embodiments of this application, it can be used to implement the functions of the access and mobility management network element.

[0079] 4. Session Management Function (SMF): Primarily used for session management, IP address allocation and management of terminal devices, selection and management of user plane functions, policy control, or endpoints of charging function interfaces, and downlink data notification. In this embodiment, it can be used to implement the functions of the session management function.

[0080] 5. Policy control function (PCF): A unified policy framework used to guide network behavior, providing policy rule information to control plane functional elements (such as AMF, SMF, etc.).

[0081] 6. Application Function (AF): Used for data routing affected by applications, accessing open network function elements, or interacting with the policy framework for policy control, etc.

[0082] 7. Unified data management (UDM): Used for unified data management, 5G user data management, processing user identification, access authentication, registration, or mobility management, etc.

[0083] 8. User plane function (UPF): This element can be used for packet routing and forwarding, or for quality of service (QoS) processing of user plane data. User data can access the data network (DN) through this element. In the embodiments of this application, it can be used to implement the functions of the user plane function.

[0084] 9. Network Slice Selection Function (NSSF): Used to manage information related to network slices.

[0085] 10. Digital Network (DN): This is a data network that provides services to terminal devices. Typically, the client is located on the terminal device, and the server is located on the data network. A data network can be a private network, such as a local area network (LAN), an external network not controlled by the operator, such as the Internet, or a dedicated network jointly deployed by operators, such as a network providing IMS services. In short, a data network is used to provide data transmission. Examples include operator networks, the Internet, and third-party business networks.

[0086] In addition, the aforementioned network architecture may also include network function (NF) repository function (NRF): used to store network function entities and their service descriptions, and to support service discovery, network element entity discovery, etc.; network exposure function (NEF): used to securely expose services and capabilities provided by 3GPP network functions to the outside world; and unified data repository (UDR): used for UDM to store or retrieve user subscription data, and PCF to store or retrieve policy data.

[0087] It should be understood that the network architecture described above in the embodiments of this application is merely an illustrative example of a network architecture described from the perspective of a traditional point-to-point architecture and a service-oriented architecture. The network architecture applicable to the embodiments of this application is not limited to this; any network architecture capable of implementing the functions of the aforementioned network elements is applicable to the embodiments of this application. This application does not limit the names of the network elements in the described network architecture, and any network device capable of implementing the functions of the aforementioned network elements is applicable to the embodiments of this application. In future communication systems such as 6G communication systems, the aforementioned network elements or devices may still use their aforementioned names, or have other names; the functions of the aforementioned network elements or devices may be performed by a single network element or by several network elements jointly, and this application does not limit this.

[0088] In actual deployment, network elements in the core network can be co-located. For example, access and mobility management function network elements can be co-located with session management function network elements; session management function network elements can be co-located with user plane function network elements; network slice selection function network elements, policy control network elements, and unified data management network elements can be co-located. When two network elements are co-located, the interaction between these two network elements provided in the embodiments of this application becomes an internal operation of the co-located network element or can be omitted.

[0089] For ease of understanding, a brief explanation of some of the terms used in this application is provided below.

[0090] 1. A public land mobile network (PLMN) is a network established and operated by a government or its approved operators for the purpose of providing land mobile communication services to the public. A PLMN is a wireless communication system geared towards mobile users on land, such as those in vehicles or on foot. Such systems can be standalone, but are often connected to fixed-line telephone systems such as the public switched telephone network.

[0091] 2. A non-public network (NPN) is a network that is distinct from the public network of telecommunications operators and provides services to specific users / industry organizations. According to the 3GPP protocol TS23.501, non-public networks have the following two types:

[0092] (1) Stand-alone NPN (SNPN) network, which is not dependent on PLMN and is operated by SNPN operator (non-operator network, such as government private network, enterprise private network).

[0093] (2) Public network integrated NPN (PNI-NPN) is a network that relies on public networks (such as 5G networks) and is operated by traditional operators.

[0094] 3. Home-routed (HR) roaming access: refers to roaming users accessing services provided by their home network through the gateway of their home network.

[0095] 4. Local breakout (LBO) roaming access: This refers to the gateway through which roaming users access services, which is the gateway of the visited network. Therefore, the policy control and billing policies of the home network need to be obtained by the visited network policy control element from the home network policy control element through the N24 interface.

[0096] Currently, mobile networks accessible to terminal devices include 2G, 3G, 4G, and 5G networks, which provide data transmission channels for services such as voice calls, video calls, and web browsing. However, the explosive growth of emerging services such as connected vehicles, virtual reality, mobile office, and the Internet of Things demands that mobile networks provide fiber-optic-like access speeds, a zero-latency user experience, the ability to connect hundreds of billions of devices, consistent service across multiple scenarios with ultra-high traffic density, ultra-high connection density, and ultra-high mobility, intelligent optimization of service and user experience, and energy efficiency improvements and bit cost reductions of over 100 times. These are the weaknesses of traditional networks, which cannot adequately support the rapid development of future services.

[0097] IP Multimedia Subsystem (IMS) is a new form of multimedia service that meets the increasingly novel and diverse multimedia service needs of today's end customers. IMS enables various types of terminals to establish IP connections, through which terminals can exchange various types of information, including voice, images, video, and files. Currently, PLMN networks can provide IMS voice services to terminal devices.

[0098] This application uses an example where the first network is SNPN and the second network is PLMN. Figure 3 This is a schematic diagram illustrating the applicable scenario of the embodiments of this application. Figure 3 This includes SNPN networks, PLMN networks, and PLMN's IMS network.

[0099] It should be noted that in this application, the PLMN and SNPN can share the UDM, that is, the UE can use the subscription in the PLMN to register with the SNPN; the PLMN and SNPN can also share the terminal identifier, for example, the subscription permanent identifier (SUPI); and the SNPN can use the PLMN's IMS network.

[0100] To facilitate understanding, the following is a brief introduction to the concepts and terms involved in the IMS network.

[0101] (1) The Home Subscriber Server (HSS) is a core user database. It provides support for the entity that actually manages calls in the IMS network. The HSS stores user and service-related data in the IMS network, including user identity, authentication data, service data, access parameters, service triggering information, and roaming information.

[0102] (2) Call session control function (CSCF): As the core part of IMS, the CSCF is responsible for processing user multimedia sessions. According to its function, it can be divided into: proxy call control function (P-CSCF), interrogation call control function (I-CSCF), and serving call control function (S-CSCF).

[0103] (3) P-CSCF: It is the interface network element between the IMS core network and the user terminal. It is responsible for user authentication, security mechanism negotiation, encryption protection, signaling compression and other functions related to the access network. It can also cooperate with the access terminal with PDF function module to complete the resource reservation function; and cooperate with I-CSCF / S-CSCF side to complete the call connection processing.

[0104] (4) I-CSCF: It is the entry point of the IMS home network. It selects the appropriate S-CSCF for incoming calls to the P-CSCF in the home network and provides access to the external IMS network of the visited network.

[0105] (5) S-CSCF: It plays a core role in IMS network session control and is responsible for terminal registration and authentication, session control, user service information management and triggering specified services to the application server (AS).

[0106] (6) AS: Provides various service processing, such as public telephone exchange simulation service, centralized user digital exchange service, etc.

[0107] (7) Media Resource Function Controller (MRFC): Parses resource control commands from S-CSCF and AS, and controls MRFP to provide media resources, such as three-way conference mixing and announcement audio.

[0108] (8) Media resource function processor (MRFP): Under the control of MRFC, it provides media resources to the terminal.

[0109] As mentioned above, a standalone non-public network (SNPN) is deployed independently and does not rely on a public land mobile network (PLMN). Currently, the PLMN's IMS can provide IMS services to terminals accessing the SNPN. However, when the SNPN does not provide IMS voice capabilities, how the SNPN can utilize the PLMN's IMS to provide IMS services to terminal devices becomes a technical problem that needs to be solved.

[0110] This application provides a voice communication method and apparatus that enables SNPN to use PLMN's IMS to provide IMS services to terminals, ensuring user experience.

[0111] It should be noted that, for ease of understanding and explanation, the terminal device in this application is exemplified by a UE.

[0112] As mentioned above, in this embodiment, the PLMN and SNPN can share the UDM, meaning the UE can register with the SNPN using a subscription from the PLMN; the PLMN and SNPN can also share the terminal identifier, such as SUPI; and the SNPN is allowed to use the PLMN's IMS network for IMS services. This can also be understood as the SNPN and PLMN sharing a common P-CSCF network element.

[0113] Figure 4 This is a schematic flowchart of the voice communication method 400 of this application. Figure 4 The method 400 shown can be derived from Figure 2 or Figure 3 The system shown executes network elements such as AMF, SMF, UPF, UDM, and P-CSCF. Figure 4 The method shown includes steps S401 to S405. In this embodiment, the terminal device is described using a UE as an example, and each step is described in detail below.

[0114] Step S401: The first network element obtains the first Internet Protocol IP address of the terminal device registered in the first network.

[0115] In one possible implementation, the first network element can be a P-CSCF network element, and the first network can be an SNPN. For example, the P-CSCF network element can obtain the multimedia registration information of the user equipment (UE) registered in the SNPN, and the registration information may include the UE's first IP address.

[0116] In step S402, the first network element sends first information to the second network element. The first information includes a first IP address, which is the IP address related to the first connection of the terminal device. The first connection is used to access the Internet Protocol Multimedia Subsystem (IMS).

[0117] In one possible implementation, the second network element can be a PCF network element. For example, the P-CSCF network element can send application session information to the PCF. The application session information includes a first IP address, which is the IP address associated with the first connection of the terminal device. The first connection is used to access the Internet Protocol Multimedia Subsystem (IMS). In this application, the first connection can be used for the terminal device to access the IMS. Optionally, the application session information may also include at least one of the following: a source port, a destination port, and a destination IP address. Here, the destination port or destination IP address refers to the port and IP address of the communication peer of the terminal device. In this application, the first connection can be used to carry a multimedia IP flow (IM flow).

[0118] In this application, during the IMS session establishment process, the P-CSCF can establish a first connection upon receiving a signaling offering a session description protocol (SDP) offer. For example, the P-CSCF can establish a first connection upon receiving a session initiation protocol (SIP) invite signaling. The SIP invite signaling includes the SDP offer. For example, the process of the P-CSCF establishing a first connection upon receiving the SDP offer signaling can be found in Appendix B of TS 29.513.

[0119] It should be noted that when the SNPN and PLMN do not have a common PCF, the second network element here can be the PCF in the SNPN; when the SNPN and PLMN have a common PCF, the second network element here can refer to the common PCF; when both the SNPN and PLMN have PCFs, the second network element here can refer to the PCF in the SNPN. For example, the P-CSCF network element sends the first information to the PCF in the SNPN through the PCF in the PLMN.

[0120] In step S403, the first network element receives first indication information from the second network element. The first indication information is used to instruct the terminal device to switch or redirect from the first network to the second network. The second network provides the IMS to the terminal device.

[0121] In one possible implementation, the P-CSCF network element can receive first indication information from the PCF network element. This first indication information can be used to instruct the UE to switch or redirect from the SNPN to the PLMN. Alternatively, it can be understood that the SNPN does not provide IMS voice capabilities, but can provide IMS services to the UE via the PLMN network.

[0122] Step S404: The first network element obtains the second IP address of the terminal device registered in the second network.

[0123] In one possible implementation, after the UE switches or redirects to the PLMN network, it can register in the PLMN and then register or update its information again in the IMS network, thereby reporting a new IP address (e.g., a second IP address).

[0124] The P-CSCF network element can obtain the UE's second IP address through a registration message (e.g., a Register message); in one possible implementation, the P-CSCF network element can obtain the UE's second IP address through a UE address change message (e.g., an invite message).

[0125] Step 405: The first network element establishes a second connection based on the first instruction information and the second IP address of the terminal device.

[0126] In one possible implementation, the P-CSCF network element can re-establish a connection (e.g., a second connection) in the PLMN based on the first indication information and the UE's new IP address. In this application, the second connection can be used for terminal equipment to access IMS. For example, after the P-CSCF network element obtains the UE's new IP address, it can re-initiate the IMS voice connection establishment request based on the first indication information to establish the second connection.

[0127] It should be understood that in this application, the target port or target IP address of the first connection and the second connection is the same. Here, the target port or target IP address refers to the port and IP address of the communication peer of the terminal device.

[0128] According to the method provided in the embodiments of this application, when the SNPN does not provide IMS voice capability, the UE can be switched or redirected to the PLMN network, and the PLMN network can be used to provide IMS service to the terminal device. The terminal device makes an IMS call between the first network and the communication peer to trigger the establishment of a first connection. The first network element establishes a second connection for the terminal device according to the first indication information. It is not necessary to wait for the terminal device to switch or redirect to the second network and make another IMS call with the communication peer to trigger the establishment of a second connection, which saves signaling and ensures the user's service experience.

[0129] Figure 5 This is a schematic flowchart of a voice communication method 500 according to a specific embodiment of this application. Figure 5 The method 500 shown can be derived from Figure 2 or Figure 3 The system shown executes network elements such as AMF, SMF, UPF, UDM, and P-CSCF. Figure 5 The method shown includes steps S501 to S512. In this embodiment, the terminal device is described using a UE as an example, and each step is described in detail below.

[0130] In this embodiment, the SNPN and PLMN share a common P-CSCF network element. The PLMN and SNPN may not support common SMF or UPF or Home Routeed (HR) Protocol Data Unit (PDU) sessions. That is, in this embodiment, the SNPN cannot use the SMF or UPF in the PLMN to establish a session; it can use the SMF / UPF in the SNPN network. However, the AMF in the SNPN can determine whether the SNPN supports IMS services based on configuration information or RAN indication information. In this application, SNPN supporting IMS services, or services in general, can be understood as the SNPN redirecting or switching terminals accessing the SNPN to its PLMN to use IMS voice services. It can also be understood as the first network supporting IMS services for UEs accessing the first network, or the first network using the IMS of the second network to provide IMS services for UEs accessing the first network.

[0131] Step S501: The UE registers with the SNPN network using the PLMN's subscription.

[0132] In one possible implementation, the UE can register with the SNPN network using a PLMN subscription.

[0133] As an example: The UE can initiate a registration request to the SNPN AMF. The AMF in the SNPN obtains the UE's PLMN subscription data from the PLMN's UDM and authenticates the UE based on the subscription data.

[0134] In step S502, the AMF determines whether the SNPN supports IMS services.

[0135] For example, the AMF determines a third indication information based on at least one of the configuration information and the indication information sent by the RAN (e.g., the base station) to the AMF. The third indication information is used to indicate whether the SNPN supports IMS services.

[0136] For example, configuration information may include: local policy information, UE radio capabilities information, and roaming agreements information.

[0137] For example, the RAN's indication information may include: information about the RAN's voice support match indicator, used to indicate whether the RAN supports IMS services.

[0138] The configuration information may further include at least one of the following: whether the SNPN supports connection to the PLMN's IMS; whether it supports HR roaming for IMS voice communication with the PLMN; whether the SNPN has a common network element (such as SMF / UPF) with the PLMN; and whether the SNPN has a common P-CSCF with the PLMN. In this application, the common SMF or UPF between the SNPN and PLMN can also be understood as the SMF or UPF being deployed simultaneously in both the PLMN and SNPN, or serving both the PLMN and SNPN simultaneously. Whether the SNPN has a common P-CSCF with the PLMN can be understood as the SNPN and PLMN being able to connect to the same P-CSCF network element in the IMS.

[0139] For example, local policy information and / or roaming information may include at least one of the following: whether the SNPN supports IMS connection to the PLMN, whether the SNPN supports HR roaming with the PLMN via IMS voice, or whether the SNPN has a common SMF, UPF, or P-CSCF with the PLMN.

[0140] As an example, the AMF can determine whether the SNPN supports connecting to the PLMN's IMS based on the roaming agreement, i.e., whether the SNPN can access the PLMN's IMS system. Furthermore, if the AMF determines that there is a connection between the SNPN and the PLMN's IMS and that the Service Level Agreement (SLA) between the SNPN and the PLMN supports IMS services, then the AMF determines that the SNPN supports connecting to the PLMN's IMS.

[0141] It should be understood that when a UE uses IMS services, there are certain requirements for the RAN's transmission commands or configurations; for example, the base station must meet specific design requirements. Therefore, the AMF can also determine whether the access network equipment in the SNPN supports IMS service transmission, i.e., whether it has the capability to transmit IMS services. In other words, the indication information is used to indicate whether the RAN has the capability to transmit IMS services. For example, the RAN can determine the Voice Support Match Indicator. That is, the RAN determines whether it supports transmitting IMS services.

[0142] It should be understood that the RAN's instruction information can be either stored locally by the AMF or sent by the RAN to the AMF.

[0143] In this application, the RAN can also determine whether the RAN of the PLMN adjacent to the SNPN supports IMS services.

[0144] As an example, if the RAN determines that the RAN of the PLMN adjacent to the SNPN supports IMS services, and the SNPN RAN supports handing over or redirecting the UE to the RAN of the adjacent PLMN during the establishment of the IMS Voice QoS Flow, then the RAN sends an indication message to the AMF, indicating that the RAN supports the transmission of IMS services; or, if the RAN determines that it supports IMS voice over PS session over NR, then the RAN sends an indication message to the AMF, indicating that the RAN supports the transmission of IMS services; or, if the RAN does not support IMS voice over PS session over NR and does not support handing over or redirecting the UE to the PLMN during the establishment of the IMS Voice QoS Flow, then the RAN sends an indication message to the AMF, indicating that the RAN does not support IMS services.

[0145] It should be understood that in this application, the RAN sends an indication message to the AMF, indicating that the RAN supports the transmission of IMS services. This may be because the RAN determines that the RAN currently serving the UE does not support the transmission of IMS services, but the SNPNRAN can switch or redirect the UE to another RAN in the PLMN to provide IMS services for the UE. In this case, the RAN can send the indication message to the AMF. Alternatively, the RAN may determine that the current RAN supports IMS voice over PS session over NR, in which case the RAN can also send this indication message to the AMF.

[0146] Specifically, the criteria for determining AMF in this application may include, but are not limited to, the following:

[0147] In one possible implementation, if the AMF determines, based on configuration information, that the SNPN does not support IMS connection to the PLMN and does not provide IMS itself, then the AMF determines that the SNPN does not support IMS services. For example, the AMF determines that the IMS Voice over PSSession Supported indication is not supported.

[0148] In one possible implementation, when the AMF determines, based on indication information from the access network equipment, that the RAN does not support IMS service transmission, then the AMF determines that the SNPN does not support IMS service. For example, the AMF determines that the IMS Voice over PS SessionSupported indication is not supported.

[0149] In one possible implementation, if the AMF determines that the SNPN supports IMS connection to the PLMN based on configuration information, but the AMF determines that the RAN does not support IMS service transmission based on indication information from the access network equipment, then the AMF determines that the SNPN does not support IMS service. For example, the AMF determines that the IMS Voice over PS Session Supported indication is not supported.

[0150] In one possible implementation, when the AMF determines, based on configuration information, that the SNPN supports IMS connected to the PLMN, and the AMF determines, based on indication information from the access network equipment, that the RAN supports IMS service transmission, then the AMF determines that the SNPN supports IMS services. For example, the AMF determines that the IMS Voice over PS Session Supported indication is supported.

[0151] In one possible implementation, when the AMF determines, based on configuration information, that the SNPN supports IMS connection to the PLMN, and the AMF determines that the SNPN supports IMS voice over PSSession (HR) sessions with the PLMN, and the AMF determines, based on indication information from the access network equipment, that the RAN supports IMS service transmission, then the AMF determines that the SNPN supports IMS services. For example, the AMF determines that the IMS Voice over PSSession Supported indication is supported.

[0152] In one possible implementation, when the AMF determines, based on configuration information, that the SNPN supports IMS connection to the PLMN, and the AMF determines that there are common session management function network elements and / or common user plane function network elements between the SNPN and the PLMN, and the AMF determines, based on the indication information from the access network equipment, that the RAN supports the transmission of IMS services, then the AMF determines that the SNPN supports IMS services. For example, the AMF determines that IMS Voice over PS Session Supported indication is supported.

[0153] In one possible implementation, when the SNPN and PLMN share a common P-CSCF network element, the AMF determines, based on configuration information, that the SNPN supports IMS connection to the PLMN, and based on indication information from the access network equipment, the AMF determines that the RAN supports IMS service transmission. Therefore, the AMF determines that the SNPN supports IMS service. For example, the AMF determines that IMS Voice over PS SessionSupported indication is supported.

[0154] As described above, the scenario assumed in this embodiment is that the PLMN and SNPN may not support common SMF / UPF or home routed (HR) protocol data unit (PDU) sessions, but they have common P-CSCF network elements, and the AMF in the SNPN can determine that the SNPN supports IMS services based on the configuration information and the indication information of the RAN.

[0155] This embodiment assumes that the AMF determines that the SNPN supports IMS services based on the configuration information and indication information.

[0156] Step S503: The SNPN-AMF sends a third indication message to the UE, which is used to indicate that the SNPN supports IMS services.

[0157] As an example, the UE receives a registration response message from the SNPN-AMF; the message carries an IMS Voice over PS Session Supported indication, indicating that the SNPN supports IMS services.

[0158] It should be noted that if the AMF determines in step S502 that the SNPN does not support IMS services, then in step S504, the SNPN-AMF sends an indication to the UE that the SNPN does not support IMS services. In this case, steps S504-S513 of this embodiment are not executed.

[0159] Step S504: SNPN-SMF obtains the address information of P-CSCF.

[0160] As an example, a UE can establish a PDU session, and then the SNPN SMF can obtain the P-CSCF address information according to the network configuration. For example, the SNPN-SMF obtains the P-CSCF address during the PDU session establishment process, which can be referred to section 4.3.2 of 3GPP technical specification (TS) 23.502, and will not be elaborated here.

[0161] In step S505, the SNPN-SMF sends the address information of the P-CSCF to the UE and / or UDM.

[0162] In one possible implementation, in step S505a, the SNPN-SMF sends a PDU session message to the UE, carrying the address information of the P-CSCF. In another possible implementation, in step S505b, the SMF sends a Nudm_UECM_Registration message to the UDM, carrying the address information of the P-CSCF. In yet another possible implementation, both S505a and S505b are executed.

[0163] Step S506: The UE registers in the PLMN's IMS system.

[0164] For example, the UE can register in the IMS system based on the address information of the P-CSCF obtained in step S505. For instance, the UE's registration in the PLMN's IMS system can be referenced to 3GPP technical specification TS 23.228.

[0165] It should be noted that after the UE registers in the IMS system, the P-CSCF can obtain the UE's multimedia registration information, which includes the UE's first Internet Protocol (IP) IP address.

[0166] Step S507, UE's IMS Voice connection establishment process.

[0167] In one possible implementation, the UE triggers the establishment of an IMS voice session, for example, a mobile-organized IMS voice call.

[0168] In one possible implementation, the network triggers the establishment of an IMS voice session, for example, the mobile terminated an IMS voice call.

[0169] In step S508, SNPN-SMF sends request #1 to the RAN to request PDU session modification and create QoS Flow for IMS Voice.

[0170] Specifically, in one possible implementation, the P-CSCF sends first information (e.g., application session information) to the PCF. This first information includes a first IP address, which is the IP address associated with the terminal device's first connection used to access the Internet Protocol Multimedia Subsystem (IMS). The PCF can then forward the first information to the SMF. The SNPN-SMF then sends request #1 to the RAN to request PDU session modification and create a QoS flow for the IMS Voice.

[0171] In this application, the first connection is used for the UE to access the Internet Protocol Multimedia Subsystem (IMS). The first information may also include: source port and destination port. Alternatively, the first information may include: destination IP address. Here, destination port or destination IP address refers to the port and IP address of the communication peer of the terminal device.

[0172] In this application, during the IMS session establishment process, the P-CSCF can establish a first connection upon receiving a signaling offering a session description protocol (SDP) offer. For example, the P-CSCF can establish a first connection upon receiving a session initiation protocol (SIP) invite signaling. The SIP invite signaling includes the SDP offer. For example, the P-CSCF establishing a first connection upon receiving an SDP offer can be referenced to Appendix B of 3GPP TS 29.513.

[0173] Optionally, in this step, when the SNPN-AMF forwards request #1 to the RAN via the N2 message, it can indicate in the N2 message whether the SNPN-RAN can fall back the UE to the RAN in the PLMN, that is, whether a PLMNF fallback can be performed. For example, when there is an N14 interface between the SNPN-AMF and the PLMN, or when the SNPN-AMF shares an AMF with the PLMN, it can indicate in the N2 message whether the RAN in the SNPN system can fall back the UE to the RAN in the PLMN system.

[0174] In step S509, the RAN receives SNPN-SMF request #1 and determines whether to proceed with the PDU session modification procedure.

[0175] Specifically, the RAN can determine whether a PDU session modification procedure can be performed based on the UE's capabilities, local configuration, and AMF instructions.

[0176] In one possible implementation, the RAN in the SNPN does not have IMS Voice capabilities, but it can determine whether the UE can be switched / redirected to the RAN in the PLMN based on the UE's capability information and / or the characteristics of the RAN, and therefore rejects the PDU session modification request from the SNPN-SMF. If the SNPN-AMF indicates that the UE can fall back to the PLMN, the RAN of the SNPN determines to switch the UE to the PLMN; otherwise, the RAN of the SNPN determines to redirect to the PLMN.

[0177] In step S510, the RAN sends a response #1 to the SNPN-SMF, instructing the RAN to reject the SNPN-SMF's PDU session modification request and indicating that IMS Voice Fallback is in progress.

[0178] It should be understood that in this step, the SNPN-SMF can also send message #1 to the PCF to indicate that IMS Voice Fallback is in progress; the PCF can forward message #1 to the P-CSCF to notify the P-CSCF that IMS Voice Fallback is in progress.

[0179] This can also be understood as the PCF sending a first indication message to the P-CSCF, which can be used to instruct the UE to hand over or redirect from the SNPN to the PLMN. Upon receiving the first indication message, the P-CSCF can save state information, such as a second indication message. This second indication message is used to instruct the P-CSCF to re-initiate the QoS Flow establishment request for IMS voice (e.g., a second connection) after the UE hands over or redirects to the second network. Alternatively, it can be understood as the P-CSCF re-initiating the IMS voice connection establishment request when the UE moves to the target PLMN.

[0180] In step S511, the RAN in the SNPN switches or redirects the UE to the PLMN.

[0181] In one possible implementation, the RAN can hand over or redirect the UE to the PLMN. For example, the RAN in the SNPN handing over or redirecting the UE to the PLMN can refer to section 4.2.6 or section 4.11.1.3.2 of 3GPP TS 23.502.

[0182] When a UE hands over or redirects to a PLMN, the PLMN's SMF can determine the P-CSCF address information through the UE or UDM. For example, the UE may send the P-CSCF address information obtained in step S505 to the PLMN's SMF in the PDU session establishment or modification request message; or the UDM may send the P-CSCF address information obtained in step S505 to the PLMN's SMF in the Nudm_UECM_Registration response message.

[0183] In step S512, the UE obtains a new IP address and re-registers or updates in the IMS.

[0184] It should be noted that when a UE hands over or redirects to a PLMN, the UE's session anchor point changes, meaning the UE's Internet Protocol (IP) address changes. At this time, the UE can re-register with the P-CSCF using the new IP address or notify the IMS of the UE's new IP address. In other words, the P-CSCF can obtain a second IP address for the UE.

[0185] In one possible implementation, the P-CSCF can obtain the UE's second IP address through a registration message (e.g., a Register message), or the P-CSCF can obtain the UE's second IP address through a UE address change message (e.g., an Invite message).

[0186] In step S513, the P-CSCF re-initiates the IMS voice connection establishment request based on the first indication information received in step S510 and the second IP address of the UE.

[0187] For example, the P-CSCF can, based on the PCF indication information received in step S510, wait for the UE to move to the target PLMN before re-initiating the IMS voice connection establishment request (e.g., establishing a second connection).

[0188] It should be understood that in this application, the target port or target IP address of the first connection and the second connection is the same. Here, the target port or target IP address refers to the port and IP address of the communication peer of the terminal device.

[0189] According to the method provided in this embodiment, the PLMN and SNPN share the UDM and UE identifiers, and the UE in the SNPN can connect to the IMS system in the PLMN. During the IMS service establishment process, the SNPN can redirect or switch the UE to the PLMN. The P-CSCF in the IMS can save the UE's status information and assist the UE in restoring the IMS service connection in the target PLMN. Thus, the SNPN can use the IMS in the PLMN to provide IMS services to the UE, ensuring user experience.

[0190] Figure 6 This is a schematic flowchart of method 600 provided in an embodiment of this application. Figure 6 The method 600 shown can be derived from Figure 2 or Figure 3 The system shown executes network elements such as AMF, SMF, UPF, UDM, and P-CSCF. Figure 6 The method shown may include steps S601 to S612. In this embodiment, the terminal device is described using a UE as an example, and each step is described in detail below.

[0191] In this embodiment, HR sessions can be supported between the PLMN and the SNPN. Furthermore, the AMF in the SNPN can determine whether the SNPN supports IMS services based on configuration information or RAN instructions.

[0192] It should be noted that steps S601 to S603 can be referred to steps S501 to S503 in method 500, and will not be repeated here.

[0193] In this embodiment, HR sessions can be supported between PLMN and SNPN. That is, during the establishment of IMS Voice PDU sessions, SNPN AMF can select SMF or UPF in PLMN for IMS Voice PDU sessions.

[0194] Step S604: The SMF in the PLMN obtains the address information of the P-CSCF.

[0195] As an example, the UE can establish a PDU session, and the PLMN SMF can obtain the address information of the P-CSCF according to its local configuration. For example, the PLMN SMF obtains the address information of the P-CSCF by referring to section 4.3.2 of 3GPP technical specification (TS) 23.502, which will not be repeated here.

[0196] Step S605: The SMF in the PLMN sends the address information of the P-CSCF to the UE.

[0197] In one possible implementation, the SMF / UPF in the PLMN sends a PDU session message to the UE, which carries the address information of the P-CSCF to facilitate the UE's registration in the IMS system.

[0198] Step S606: The UE registers in the PLMN's IMS system.

[0199] It should be understood that the UE can register in the PLMN's IMS system using existing technical methods. For example, the UE registration in the PLMN's IMS system can refer to the 3GPP technical specification (TS) TS 23.228, which will not be elaborated here.

[0200] For example, the UE can perform initial registration in the IMS system based on the address information of the P-CSCF obtained in step S605.

[0201] Step S607, UE's IMS Voice connection establishment process.

[0202] In one possible implementation, the UE triggers the establishment of a calling / called IMS voice session, for example, a MobileOrginated IMS voice call.

[0203] In one possible implementation, the network triggers the establishment of an IMS voice session, for example, a Mobile Terminated IMS voice call.

[0204] In step S608, the SMF in the PLMN sends request #1 to the SMF in the SNPN to request PDU session modification and create an IMS Voice QoS Flow. The SMF in the SNPN then forwards request #1 to the RAN.

[0205] Optionally, in this step, when the SNPN-AMF forwards request #1 to the RAN via N2 message, it can indicate in the N2 message whether the RAN in the SNPN can fall back to the RAN in the PLMN. Alternatively, in this step, when the SNPN-AMF forwards request #1 to the RAN via N2 message, it can indicate in the N2 message whether the SNPN-RAN can fall back to the RAN in the PLMN, i.e., whether PLMN fallback is possible. For example, when there is an N14 interface between the SNPN and the PLMN, or when the SNPN-AMF shares an AMF with the PLMN, the SNPN-AMF can indicate in the N2 message whether the RAN in the SNPN system can fall back to the RAN in the PLMN system.

[0206] In step S609, the RAN receives request #1 from the SNPN's SMF and determines whether the PDU session modification procedure can be performed. See step S509 in method 500 for details.

[0207] In step S610, the RAN sends response #1 to the SNPN's SMF, instructing the RAN to reject the SNPN SMF's PDU session modification request and indicating that IMS Voice Fallback is in progress. The SNPN's SMF forwards response #1 to the PLMN's SMF. It should be understood that in this step, the PLMN SMF can save state information. After the UE redirects or switches to the PLMN, the PLMN's SMF initiates a PDU session modification request in the PLMN to create an IMS Voice QoS Flow.

[0208] In step S611, the RAN switches or redirects the UE to the PLMN.

[0209] For example, when the RAN switches or redirects the UE to the PLMN, refer to section 4.2.6 or section 4.11.1.3.2 of 3GPP TS 23.502.

[0210] In step S612, the SMF in the PLMN re-establishes the IMS Voice QoS Flow in the PLMN.

[0211] In one possible implementation, the SMF in the PLMN can wait until the UE moves to the target PLMN and then request the establishment of the IMS Voice QoS Flow during the process of resuming the IMS Voice PDU session in the PLMN. For example, after the AMF in the PLMN detects that the UE has moved to the target PLMN, the SMF can receive a message from the AMF to resume the PDU session, and the SMF in the PLMN can then re-establish the IMS Voice QoS Flow in the PLMN.

[0212] According to the method provided in this embodiment, the PLMN and SNPN share the UDM and UE identifiers, and the UE in the SNPN can connect to the IMS system in the PLMN. HR sessions are established for UEs accessing the SNPN, and the UE is redirected or switched to the PLMN when establishing the IMS Voice QoS Flow. This enables the SNPN to provide IMS services to the UE through the IMS in the PLMN, ensuring user experience.

[0213] Figure 7 This is a schematic flowchart of method 700 provided in an embodiment of this application. Figure 7 The method 700 shown can be derived from Figure 2 or Figure 3The system shown executes network elements such as AMF, SMF, UPF, UDM, and P-CSCF. Figure 7 The voice communication method shown includes steps S701 to S712. In this embodiment, the terminal device is described using a UE as an example, and each step is described in detail below.

[0214] In this embodiment, the PLMN and SNPN can support a common SMF / UPF to serve IMS PDU sessions. Furthermore, the AMF in the SNPN can determine whether the SNPN supports IMS services based on configuration information or RAN instructions.

[0215] It should be noted that steps S701 to S703 can be referred to steps S501 to S503 in method 500, and will not be repeated here.

[0216] Step S704: The public SMF / UPF obtains the address information of the P-CSCF.

[0217] As an example, during the UE's PDU session establishment process, the SNPN AMF selects a public SMF / UPF to serve the PDU session. The public SMF / UPF can obtain the P-CSCF address information according to its local configuration. For example, the method for the public SMF / UPF to obtain the P-CSCF address information can be found in section 4.3.2 of 3GPP technical specification (TS) 23.502, which will not be elaborated here.

[0218] Step S705: The public SMF / UPF sends the P-CSCF address information to the UE.

[0219] In one possible implementation, the public SMF / UPF sends a PDU session message to the UE, which carries the address information of the P-CSCF to facilitate the UE's registration in the IMS system.

[0220] Step S706: The UE registers in the PLMN's IMS system.

[0221] For example, the UE can perform initial registration in the IMS system based on the address information of the P-CSCF obtained in step S705. For instance, the UE registration in the PLMN's IMS system can be referenced to 3GPP technical specification TS 23.228, which will not be elaborated upon here.

[0222] Step S707, UE's IMSVoice connection establishment process.

[0223] Specifically, refer to step S607 in method 600.

[0224] In step S708, the public SMF / UPF sends request #1 to the RAN to request PDU session modification and create an IMS VoiceQoS Flow.

[0225] Optionally, in this step, when the SNPN-AMF forwards request #1 to the RAN via N2 message, it can indicate in the N2 message whether the RAN in the SNPN can fall back to the RAN in the PLMN. Alternatively, in this step, when the SNPN-AMF forwards request #1 to the RAN via N2 message, it can indicate in the N2 message whether the SNPN-RAN can fall back to the RAN in the PLMN, i.e., whether PLMN fallback is possible. For example, when there is an N14 interface between the SNPN and the PLMN, or when the SNPN-AMF shares an AMF with the PLMN, the SNPN-AMF can indicate in the N2 message whether the RAN in the SNPN system can fall back to the RAN in the PLMN system.

[0226] In step S709, the RAN receives request #1 from the public SMF / UPF and determines whether the PDU session modification procedure can be performed. Refer to step S509 in method 500 for details.

[0227] In step S710, the RAN sends response #1 to the public SMF / UPF, instructing the RAN to reject the PDU session modification request from the public SMF / UPF and indicating that IMS Voice Fallback is in progress. It should be understood that in this step, the public SMF / UPF can save state information, and after the UE redirects or switches to the PLMN, the public SMF / UPF will initiate PDU session modification in the PLMN to create an IMS Voice QoS Flow.

[0228] In step S711, the RAN switches or redirects the UE to the PLMN.

[0229] For example, when the RAN switches or redirects the UE to the PLMN, refer to section 4.2.6 or section 4.11.1.3.2 of 3GPP TS 23.502.

[0230] Step S712: The public SMF / UPF re-establishes the IMS Voice QoS Flow in the PLMN.

[0231] In one possible implementation, the public SMF / UPF can wait until the UE moves to the target PLMN and then, during the process of resuming the IMS Voice PDU session in the PLMN, request the establishment of the IMS Voice QoS Flow. For example, after the AMF in the PLMN detects that the UE has moved to the target PLMN, the public SMF / UPF can receive a message from the AMF requesting the resumption of the PDU session, and the public SMF / UPF will then re-establish the IMS Voice QoS Flow in the PLMN.

[0232] According to the method provided in this embodiment, the PLMN and SNPN share the UDM and UE identifiers, have common SMF and UPF, and the UE in the SNPN can connect to the IMS system in the PLMN. The common SMF / UPF is selected for the IMS PDU session of the UE accessing the SNPN. When requesting to establish an IMS Voice QoS Flow, the UE is redirected or switched to the PLMN, so that the SNPN can use the IMS in the PLMN to provide IMS services to the UE, thus ensuring user experience.

[0233] Figure 8 This is a schematic flowchart of method 800 provided in an embodiment of this application. Figure 8 The method 800 shown can be derived from Figure 2 or Figure 3 The system shown executes network elements such as AMF, SMF, UPF, UDM, and P-CSCF. Figure 8 The method shown may include steps S801 to S804. In this embodiment, the terminal device is described using a UE as an example, and each step is described in detail below.

[0234] In this embodiment, the AMF in the SNPN determines that the SNPN does not support IMS services based on configuration information or indication information from the RAN.

[0235] Step S801: The UE registers with the SNPN network using the PLMN's subscription.

[0236] For details, please refer to step S501 in method 500, which will not be repeated here.

[0237] In step S802, the AMF determines whether the SNPN supports IMS services.

[0238] In one possible implementation, if the AMF determines, based on configuration information, that the SNPN does not support IMS for connection to the PLMN and does not support IMS itself (meaning the UE in the SNPN cannot access the IMS network), then the AMF determines that the SNPN does not support IMS services. For example, the AMF determines that the IMS Voice over PS Session Supported indication is not supported.

[0239] In one possible implementation, when the AMF determines, based on indication information from the access network equipment, that the RAN does not support IMS services, then the AMF determines that the SNPN does not support IMS services. For example, the AMF determines that the IMS Voice over PS SessionSupported indication is not supported.

[0240] In one possible implementation, when the AMF determines that the SNPN supports IMS connection to the PLMN based on configuration information, and the AMF determines that the RAN does not support IMS service transmission based on the indication information of the access network equipment, then the AMF determines that the SNPN does not support IMS service. For example, the AMF determines that the IMS Voice over PS Session Supported indication is not supported.

[0241] The configuration information and RAN indication information in this embodiment can be referred to in the description of S502. This embodiment assumes that the AMF determines, based on the configuration information and RAN indication information, that the SNPN does not support IMS services.

[0242] In step S803, the SNPN-AMF sends a third indication message to the UE, which is used to indicate that the SNPN does not support IMS services.

[0243] As an example, the UE receives a registration response message from the SNPN-AMF; the message carries an IMS Voice over PS Session Supported indication, indicating that the SNPN does not support IMS services.

[0244] Step S804: The UE selects a network that supports IMS services based on the configuration information.

[0245] When the AMF determines that the SNPN does not support IMS services, the UE can select a network that supports IMS services based on the configuration information. In this application, the configuration information includes multiple candidate networks. When the first candidate network has a connection with the SNPN's IMS and provides IMS services to the UE, the first candidate network has a higher priority than other candidate networks. This can also be understood as the UE needing to select another SNPN or PLMN that supports IMS services to access when the AMF determines that the SNPN does not support IMS services. Optionally, the UE can prioritize accessing the PLMN and using the IMS service.

[0246] In one possible implementation, the UE can update configuration information, which includes the SNPN's network identifier and / or third indication information.

[0247] In one possible implementation, the configuration information in this application may further include the network identifier of the candidate network and / or fourth indication information, which is used to indicate whether the candidate network supports IMS services.

[0248] According to the method provided in this implementation, the UE is allowed to reselect the network when registering with the SNPN, thereby enabling the SNPN to provide IMS services to the UE using the IMS in the PLMN, thus ensuring user experience.

[0249] The above, combined with Figures 4 to 8 The methods provided in the embodiments of this application are described in detail below. Figures 9 to 11 This application introduces a voice communication device provided in its embodiments. It should be understood that the descriptions of the device embodiments correspond to the descriptions of the method embodiments; therefore, details not described in detail can be found in the above method embodiments, and for brevity, will not be repeated here.

[0250] The above mainly describes the solutions provided by the embodiments of this application from the perspective of interaction between various network elements. It is understood that each network element, in order to achieve the above functions, includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware 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 each specific application, but such implementation should not be considered beyond the scope of this application.

[0251] This application embodiment can divide the transmitting or receiving device into functional modules according to the above method examples. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods. The following description uses the division of functional modules according to each function as an example.

[0252] Figure 9 This is a schematic block diagram of a voice communication device 100 provided in an embodiment of this application. As shown in the figure, the voice communication device 100 may include a transceiver unit 110 and a processing unit 120.

[0253] In one possible design, the voice communication device 100 can be a P-CSCF network element in the above method embodiments, or it can be a chip used to implement the functions of the P-CSCF network element in the above method embodiments. It should be understood that the voice communication device 100 can correspond to the first network element or P-CSCF network element in methods 400 and 500 according to the embodiments of this application, and the voice communication device 100 can execute the steps corresponding to the first network element or P-CSCF network element in methods 400 and 500 of the embodiments of this application. It should be understood that the specific process of each unit executing the above-mentioned corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0254] In one possible design, the voice communication device 100 can be an AMF network element in the above method embodiments, or it can be a chip used to implement the functions of the AMF network element in the above method embodiments. It should be understood that the voice communication device 100 can correspond to the AMF network element in methods 400, 500, 600, 700, and 800 according to the embodiments of this application, and the voice communication device 100 can execute the steps corresponding to the AMF network element in methods 400, 500, 600, 700, and 800 of the embodiments of this application. It should be understood that the specific process of each unit executing the above-described corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0255] In one possible design, the voice communication device 100 can be a terminal device (e.g., a user equipment UE) as described in the above method embodiments, or it can be a chip used to implement the functions of the terminal device in the above method embodiments. It should be understood that the voice communication device 100 can correspond to the terminal device in methods 400, 500, 600, 700, and 800 according to the embodiments of this application, and the voice communication device 100 can execute the steps corresponding to the terminal device in methods 400, 500, 600, 700, and 800 of the embodiments of this application. It should be understood that the specific process of each unit executing the above-described corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0256] In one possible design, the voice communication device 100 can be a UDM network element in the above method embodiments, or it can be a chip used to implement the functions of the UDM network element in the above method embodiments. It should be understood that the voice communication device 100 can correspond to the UDM network element in method 500 according to the embodiments of this application, and the voice communication device 100 can execute the steps corresponding to the UDM network element in method 500 of the embodiments of this application. It should be understood that the specific process of each unit executing the above-described corresponding steps has been described in detail in the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0257] It should also be understood that when the voice communication device 100 is a chip, the chip includes a transceiver unit and a processing unit. The transceiver unit can be an input / output circuit or a communication interface; the processing unit can be a processor, microprocessor, or integrated circuit integrated on the chip. The transceiver unit 110 is used to implement the signal transmission and reception operations of the voice communication device 100, and the processing unit 120 is used to implement the signal processing operations of the voice communication device 100. Optionally, the voice communication device 100 further includes a storage unit 130, which is used to store instructions.

[0258] This application also provides an access network device, such as... Figure 10 As shown. Device 1000 includes one or more radio frequency units, such as a remote radio unit (RRU) 1010 and one or more baseband units (BBUs) (also referred to as digital units, DUs) 1020. The RRU 1010 can be referred to as a transceiver module, which may include a transmitting module and a receiving module, or it may be a single module capable of both transmitting and receiving functions. This transceiver module can be used with... Figure 9The transceiver unit 110 corresponds to this. Optionally, this transceiver module can also be called a transceiver, transceiver circuit, or transceiver, etc., and it may include at least one antenna 1011 and a radio frequency unit 1012. The RRU 1010 part is mainly used for transmitting and receiving radio frequency signals and converting radio frequency signals to baseband signals, such as for sending indication information to terminal equipment. The BBU 1020 part is mainly used for baseband processing and controlling the base station, etc. The RRU 1010 and BBU 1020 can be physically set together or physically separated, i.e., a distributed base station.

[0259] The BBU 1020 is the control center of the base station, also known as a processing module, and can communicate with... Figure 9 The processing unit 120 in the diagram is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulation, spreading, etc. For example, the BBU (processing module) can be used to control the base station to execute the operation procedures of the network device in the above method embodiment, such as generating the above-mentioned indication information.

[0260] In one example, the BBU 1020 can be composed of one or more single boards. Multiple single boards can collectively support a single access standard wireless access network (such as an LTE network), or they can each support different access standard wireless access networks (such as LTE, 5G, or other networks). The BBU 1020 also includes a memory 1021 and a processor 1022. The memory 1021 is used to store necessary instructions and data. The processor 1022 is used to control the base station to perform necessary actions, such as controlling the base station to execute the operation procedures related to the network device in the above method embodiments. The memory 1021 and processor 1022 can serve one or more single boards. That is, each single board can have its own memory and processor, or multiple single boards can share the same memory and processor. Furthermore, each single board can also have necessary circuitry.

[0261] Figure 11 This is a schematic block diagram of a voice communication device 200 provided in an embodiment of this application. As shown, the communication device 200 includes at least one processor 220. The processor 220 is coupled to a memory and is used to execute instructions stored in the memory to transmit and / or receive signals. Optionally, the communication device 200 also includes a memory 230 for storing instructions. Optionally, the communication device 200 also includes a transceiver 210, and the processor 220 controls the transceiver 210 to transmit and / or receive signals.

[0262] It should be understood that the processor 220 and memory 230 described above can be combined into a single processing device, with the processor 220 executing the program code stored in the memory 230 to achieve the aforementioned functions. In specific implementations, the memory 230 can be integrated into the processor 220 or independent of the processor 220.

[0263] It should also be understood that transceiver 210 may include a receiver (or receiver unit) and a transmitter (or transmitter unit). The transceiver may further include an antenna, and the number of antennas may be one or more. Transceiver 210 may have a communication interface or interface circuitry.

[0264] Specifically, the transceiver 210 in the voice communication device 200 can correspond to the transceiver unit 110 in the voice communication device 100, and the processor 220 in the voice communication device 200 can correspond to the processing unit 120 in the voice communication device 200.

[0265] It should be understood that the specific process by which each transceiver processor performs the corresponding steps described above has been explained in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0266] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0267] It should be noted that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuitry in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above methods.

[0268] It is understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous-link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0269] According to the method provided in the embodiments of this application, this application also provides a computer program product, which includes: computer program code, which, when run on a computer, causes the computer to execute... Figure 3 or Figure 4 or Figure 5 or Figure 6 or Figure 7 or Figure 8 The method of any one of the embodiments shown.

[0270] According to the method provided in the embodiments of this application, this application also provides a computer-readable medium storing program code, which, when run on a computer, causes the computer to perform... Figure 3 or Figure 4 or Figure 5 or Figure 6 or Figure 7 or Figure 8 The method of any one of the embodiments shown.

[0271] According to the method provided in the embodiments of this application, this application also provides a system that includes one or more of the aforementioned devices or apparatuses.

[0272] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this 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. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0273] In the above-described device embodiments, the network-side devices correspond to the terminal devices and the network-side devices or terminal devices in the method embodiments. Corresponding modules or units execute corresponding steps. For example, the communication unit (transceiver) executes the receiving or sending steps in the method embodiments, while other steps besides sending and receiving can be executed by the processing unit (processor). The specific functions of each unit can be found in the corresponding method embodiments. There can be one or more processors.

[0274] As used in this specification, the terms "component," "module," "system," etc., are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process and / or an execution thread, and components may be located on a single computer and / or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0275] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented 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 each specific application, but such implementation should not be considered beyond the scope of this application.

[0276] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0277] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0278] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0279] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0280] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0281] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A voice communication method, characterized in that, include: The first network element obtains the first Internet Protocol (IP) address of the terminal device registered in the first network; The first network element sends first information to the second network element. The first information includes a first IP address, which is the IP address related to the first connection of the terminal device. The first connection is used to access the Internet Protocol Multimedia Subsystem (IMS). The first network element receives first indication information from the second network element. The first indication information is used to instruct the terminal device to switch or redirect from the first network to the second network. The second network provides IMS services to the terminal device through the IMS. The first network element obtains the second IP address of the terminal device registered in the second network; The first network element establishes a second connection based on the first instruction information and the second IP address of the terminal device. The second connection is used for the terminal device to access the IMS.

2. The method according to claim 1, characterized in that, The first network element establishes a second connection based on the first indication information and the second IP address of the terminal device, including: The first network element saves the status information of the terminal device according to the first indication information. The status information includes second indication information, which is used to indicate that the first network element establishes the second connection after the terminal device switches or redirects to the second network. When the first network element obtains the second IP address of the terminal device registered in the second network, the first network element establishes the second connection according to the second instruction information.

3. The method according to claim 1 or 2, characterized in that, The first network element obtains the second IP address of the terminal device registered in the second network, including: The first network element obtains the second IP address of the terminal device through a registration message, or; The first network element obtains the second IP address of the terminal device through the terminal device address change message.

4. The method according to claim 1 or 2, characterized in that, The first network is an independently deployed, non-public network.

5. The method according to claim 1 or 2, characterized in that, The second network is a public land mobile network.

6. The method according to claim 1 or 2, characterized in that, The first network element is the proxy call control function network element in the IMS network.

7. The method according to claim 1 or 2, characterized in that, The second network element is a policy control network element.

8. A voice communication method, characterized in that, include: The third network element determines third indication information based on the first condition. The third indication information is used to indicate whether the first network supports Internet Protocol Multimedia Subsystem (IMS) service. The first condition includes at least one of the following: Whether the first network supports Home Routing (HR) sessions with the second network, or; whether the first network and the second network share common session management function network elements and / or common user plane function network elements, or; whether the first network and the second network share common proxy call control function network elements, or; whether there is a connection between the IMS of the first network and the second network, wherein the second network provides the IMS service to the terminal devices registered in the first network through the IMS; The third network element sends the third instruction information to the terminal device.

9. The method according to claim 8, characterized in that, There is a connection between the IMS of the first network and the second network, and the first condition further includes: Does the Service Level Agreement (SLA) between the first network and the second network support the IMS service? 10. The method according to claim 8 or 9, characterized in that, The first network is an independently deployed, non-public network.

11. The method according to claim 8 or 9, characterized in that, The second network is a public land mobile network.

12. The method according to claim 8 or 9, characterized in that, The third network element is an access and mobility management function network element.

13. A voice communication method, characterized in that, include: The terminal device receives third indication information from a third network element in the first network, the third indication information being used to indicate that the first network does not support Internet Protocol Multimedia Subsystem (IMS) service; The terminal device determines a second network based on configuration information. The second network supports providing IMS services to the terminal device through the IMS. The configuration information includes the priority of candidate networks. When there is a connection between the first candidate network and the IMS of the first network, and the first candidate network provides the IMS services to the terminal device, the priority of the first candidate network in the configuration information is higher than the priority of other candidate networks.

14. The method according to claim 13, characterized in that, The method further includes: The terminal device updates its configuration information, which includes the network identifier of the first network and / or the third indication information.

15. The method according to claim 13 or 14, characterized in that, The configuration information also includes the network identifier of the candidate network and / or fourth indication information, the fourth indication information being used to indicate whether the candidate network supports IMS services.

16. The method according to claim 13 or 14, characterized in that, The first network is an independently deployed, non-public network.

17. The method according to claim 13 or 14, characterized in that, The second network is a public land mobile network.

18. The method according to claim 13 or 14, characterized in that, The third network element is an access and mobility management function network element.

19. A voice communication method, characterized in that, include: The unified data management network element receives second information from the session management function network element in the first network. The second information includes the address information of the proxy call control function network element in the Internet Protocol Multimedia Subsystem (IMS). The unified data management network element receives a first request from the session management function network element in the second network, and the second network provides IMS services to the terminal devices registered in the second network through the IMS. The unified data management network element sends a first response to the session management function network element in the second network, the first response including the address information of the proxy call control function network element.

20. The method according to claim 19, characterized in that, The first network is an independently deployed, non-public network.

21. The method according to claim 19 or 20, characterized in that, The second network is a public land mobile network.

22. A voice communication device, characterized in that, Includes a transceiver unit and a processing unit: The processing unit is used to obtain the first Internet Protocol (IP) address of the terminal device. The transceiver unit is used to send first information, the first information including a first IP address, the first IP address being the IP address associated with a first connection of the terminal device, the first connection being used to access the Internet Protocol Multimedia Subsystem (IMS); The transceiver unit is used to receive first indication information, which instructs the terminal device to switch or redirect from the first network to the second network, and the second network provides IMS services to the terminal device through the IMS. The processing unit is used to obtain the second IP address of the terminal device; The processing unit is used to establish a second connection based on the first indication information and the second IP address of the terminal device, the second connection being used for the terminal device to access the IMS.

23. The apparatus according to claim 22, characterized in that, The processing unit is further configured to save the status information of the terminal device according to the first indication information, the status information including second indication information, the second indication information being used to indicate that after the terminal device switches or redirects to the second network, the voice communication device establishes the second connection; When the processing unit obtains the second IP address, the processing unit establishes the second connection according to the second instruction information.

24. The apparatus according to claim 22 or 23, characterized in that, The processing unit obtains the second IP address of the terminal device through the registration message, or; The processing unit obtains the second IP address of the terminal device through the terminal device address change message.

25. The apparatus according to claim 22 or 23, characterized in that, The first network is an independently deployed, non-public network.

26. The apparatus according to claim 22 or 23, characterized in that, The second network is a public land mobile network.

27. A voice communication device, characterized in that, Includes a transceiver unit and a processing unit: The processing unit is configured to determine third indication information based on a first condition, the third indication information being used to indicate whether the first network supports Internet Protocol Multimedia Subsystem (IMS) service, and the first condition includes at least one of the following: Whether the first network supports Home Routing (HR) sessions with the second network, or; whether the first network and the second network share common session management function network elements and / or common user plane function network elements, or; whether the first network and the second network share common proxy call control function network elements, or; whether there is a connection between the IMS of the first network and the second network, wherein the second network provides IMS services to terminal devices registered in the first network through the IMS; The transceiver unit is used to send the third instruction information.

28. The apparatus according to claim 27, characterized in that, There is a connection between the IMS of the first network and the second network. The first condition also includes whether the Service Level Agreement (SLA) between the first network and the second network supports the IMS service.

29. The apparatus according to claim 27 or 28, characterized in that, The first network is an independently deployed, non-public network.

30. The apparatus according to claim 27 or 28, characterized in that, The second network is a public land mobile network.

31. A voice communication device, characterized in that, Includes processing unit and transceiver unit: The transceiver unit is used to receive third indication information, which indicates that the first network does not support Internet Protocol Multimedia Subsystem (IMS) service. The processing unit is used to determine a second network based on configuration information. The second network supports providing IMS services to terminal devices through the IMS. The configuration information includes the priority of candidate networks. When there is a connection between the first candidate network and the IMS of the first network, and the first candidate network provides the IMS services to the terminal device, the priority of the first candidate network in the configuration information is higher than the priority of other candidate networks.

32. The apparatus according to claim 31, characterized in that, The processing unit is also used to update configuration information, which includes the network identifier of the first network and / or the third indication information.

33. The apparatus according to claim 31 or 32, characterized in that, The configuration information also includes the network identifier of the candidate network and / or fourth indication information, the fourth indication information being used to indicate whether the candidate network supports IMS services.

34. The apparatus according to claim 31 or 32, characterized in that, The first network is an independently deployed, non-public network.

35. The apparatus according to claim 31 or 32, characterized in that, The second network is a public land mobile network.

36. A voice communication device, characterized in that, Includes transceiver units: The transceiver unit is used to receive second information from the session management function network element in the first network, the second information including the address information of the proxy call control function network element in the Internet Protocol Multimedia Subsystem (IMS); The transceiver unit is used to receive a first request from a session management function network element in the second network, and the second network provides IMS services to terminal devices registered in the first network through the IMS. The transceiver unit is used to send a first response to the session management function network element in the second network, the first response including the address information of the proxy call control function network element.

37. The apparatus according to claim 36, characterized in that, The first network is an independently deployed, non-public network.

38. The apparatus according to claim 36 or 37, characterized in that, The second network is a public land mobile network.

39. A computer-readable storage medium, characterized in that, The computer program stores a method which, when run on a computer, causes the computer to perform the method as described in any one of claims 1 to 7, or causes the computer to perform the method as described in any one of claims 8 to 12, or causes the computer to perform the method as described in any one of claims 13 to 18, or causes the computer to perform the method as described in any one of claims 19 to 21.

40. A communication system, characterized in that, include: A first network element for performing the method as described in any one of claims 1 to 7 and a second network element for communicating with the first network element.

41. A communication system, characterized in that, include: A third network element for performing the method as described in any one of claims 8 to 18 and a terminal device for communicating with the third network element.

42. A communication system, characterized in that, include: A unified data management network element for performing the method as described in any one of claims 19 to 21, and a session management function network element in a first network and a session management function network element in a second network for communicating with the unified data management network element.

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