Call method, information transmission method, apparatus, and device

Abstract

The present application relates to the technical field of communications, and discloses a call method, an information transmission method, an apparatus, and a device. The call method of the embodiments of the present application comprises: a terminal executes a call operation when in a state of registering with a first mobile communication network, the call operation comprising at least one of the following: initiating a first call request by means of a second mobile communication network or a third mobile communication network; and sending a call response by means of a second mobile communication network or a third mobile communication network, wherein the call response is a call response to a second call request, and the second call request is a call request received by the terminal by means of the first mobile communication network.

Description

Communication methods, information transmission methods, devices and equipment

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410937046.X, filed on July 12, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of communication technology, specifically relating to a call method, an information transmission method, a device, and equipment. Background Technology

[0004] In the initial deployment phase of some mobile communication networks, voice calls may not be supported. For example, 6G mobile communication networks may not support voice calls in the initial deployment phase. As a result, terminals cannot make calls after registering with these mobile communication networks, leading to poor terminal call performance. Summary of the Invention

[0005] This application provides a call method, information transmission method, apparatus, and device that can solve the problem of poor terminal call performance.

[0006] Firstly, a method for making a call is provided, including:

[0007] When the terminal is registered with the first mobile communication network, it performs a call operation, which includes at least one of the following:

[0008] Initiate the first call request through the second or third mobile communication network;

[0009] A call response is sent through a second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network.

[0010] Secondly, an information transmission method is provided, including:

[0011] A first network-side device sends first information to a terminal, wherein the first network-side device is a network-side device of a first mobile communication network, and the first information is used to indicate at least one of the following:

[0012] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0013] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0014] It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0015] It supports or does not support falling back to the third mobile communication network.

[0016] Thirdly, an information transmission method is provided, including:

[0017] The second network-side device receives the request to establish a multimedia session;

[0018] The establishment request includes at least one of the following:

[0019] Identification information for multimedia sessions;

[0020] Information used to indicate the retention of multimedia sessions;

[0021] Information used to indicate the establishment of a joint session;

[0022] The identification information of the multimedia session refers to the multimedia session established by the terminal in the first mobile communication network.

[0023] Fourthly, an information transmission method is provided, including:

[0024] The third network-side device receives the registration request sent by the terminal;

[0025] The third network-side device sends an update request to the fourth network-side device according to the registration request;

[0026] The third network-side device receives information from the fourth network-side device regarding the second network-side device corresponding to the establishment of a multimedia session by the terminal in the first mobile communication network.

[0027] Fifthly, an information transmission method is provided, including:

[0028] The fourth network-side device receives the update request;

[0029] The fourth network-side device sends information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network.

[0030] Sixthly, an information transmission method is provided, including:

[0031] The terminal acquires first information from a first mobile communication network, wherein the first information is used to indicate at least one of the following:

[0032] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0033] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0034] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0035] It supports or does not support falling back to the third mobile communication network.

[0036] Seventhly, an information transmission method is provided, including:

[0037] The terminal sends a multimedia session establishment request to a network-side device in a second or third mobile communication network, the establishment request including at least one of the following:

[0038] Identification information for multimedia sessions;

[0039] Information used to indicate the retention of multimedia sessions;

[0040] Information used to indicate the establishment of a joint session;

[0041] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0042] Eighthly, a communication device is provided, comprising:

[0043] The processing module is configured to perform a call operation when the first mobile communication network is in a registered state, the call operation including at least one of the following:

[0044] Initiate the first call request through the second or third mobile communication network;

[0045] A call response is sent through a second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network.

[0046] Ninthly, an information transmission device is provided, comprising:

[0047] The sending module is used to send first information to the terminal. The network-side device corresponding to the device is a network-side device of a first mobile communication network. The first information is used to indicate at least one of the following:

[0048] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0049] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0050] It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0051] It supports or does not support falling back to the third mobile communication network.

[0052] Tenthly, an information transmission device is provided, comprising:

[0053] The receiving module is used to receive requests to establish multimedia sessions;

[0054] The establishment request includes at least one of the following:

[0055] Identification information for multimedia sessions;

[0056] Information used to indicate the retention of multimedia sessions;

[0057] Information used to indicate the establishment of a joint session;

[0058] The identification information of the multimedia session refers to the multimedia session established by the terminal in the first mobile communication network.

[0059] Eleventhly, an information transmission device is provided, comprising:

[0060] The receiving module is used to receive registration requests sent by the terminal;

[0061] The sending module is used to send an update request to the fourth network-side device according to the registration request;

[0062] The receiving module is also used to receive information from the fourth network-side device regarding the second network-side device corresponding to the establishment of a multimedia session by the terminal in the first mobile communication network.

[0063] In a twelfth aspect, an information transmission device is provided, comprising:

[0064] The receiving module is used to receive update requests;

[0065] The sending module is used to send information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network.

[0066] In a thirteenth aspect, an information transmission device is provided, comprising:

[0067] A receiving module is configured to acquire first information from a first mobile communication network, wherein the first information is used to indicate at least one of the following:

[0068] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0069] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0070] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0071] It supports or does not support falling back to the third mobile communication network.

[0072] In a fourteenth aspect, an information transmission device is provided, comprising:

[0073] The sending module is configured to send a multimedia session establishment request to a network-side device in a second or third mobile communication network, wherein the establishment request includes at least one of the following:

[0074] Identification information for multimedia sessions;

[0075] Information used to indicate the retention of multimedia sessions;

[0076] Information used to indicate the establishment of a joint session;

[0077] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0078] In a fifteenth aspect, a communication device is provided, the device being configured to perform the steps of the method described in the first aspect.

[0079] In a sixteenth aspect, an information transmission apparatus is provided, the apparatus being configured to perform the steps of the method described in the second aspect, or implement the steps of the method described in the third aspect, or implement the steps of the method described in the fourth aspect, or implement the steps of the method described in the fifth aspect, or implement the steps of the method described in the sixth aspect, or implement the steps of the method described in the seventh aspect.

[0080] In a seventeenth aspect, a terminal is provided, the terminal including a processor and a memory, the memory storing a program or instructions executable on the processor, wherein when the program or instructions are executed by the processor, they implement the steps of the method as described in the first aspect, the steps of the method as described in the sixth aspect, and the steps of the method as described in the seventh aspect.

[0081] Eighteenthly, a terminal is provided, including a processor and a communication interface, wherein the processor is configured to perform a call operation when a first mobile communication network is in a registered state, the call operation including at least one of the following: initiating a first call request through a second mobile communication network or a third mobile communication network; sending a call response through the second mobile communication network or the third mobile communication network, wherein the call response is a call response to a second call request, the second call request being a call request received by the terminal through the first mobile communication network.

[0082] In a nineteenth aspect, a network-side device is provided, comprising a processor and a memory, the memory storing a program or instructions executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the method as described in the second aspect, or the program or instructions, when executed by the processor, implement the steps of the method as described in the third aspect, or the program or instructions, when executed by the processor, implement the steps of the method as described in the fourth aspect, or the program or instructions, when executed by the processor, implement the steps of the method as described in the fifth aspect.

[0083] In a twentieth aspect, a network-side device is provided, including a processor and a communication interface, wherein the communication interface is used to send first information to a terminal, the network-side device is a network-side device of a first mobile communication network, and the first information is used to indicate at least one of the following: supporting multimedia service transmission through the first mobile communication network or not supporting multimedia service transmission through the first mobile communication network; supporting multimedia service transmission through a second mobile communication network or not supporting multimedia service transmission through the second mobile communication network; supporting multimedia service transmission through a third mobile communication network or not supporting multimedia service transmission through the third mobile communication network; supporting fallback to the third mobile communication network or not supporting fallback to the third mobile communication network.

[0084] In a twenty-first aspect, a network-side device is provided, including a processor and a communication interface, wherein the communication interface is used to receive a multimedia session establishment request; wherein the establishment request includes at least one of the following: identification information of the multimedia session; information for indicating the retention of the multimedia session; information for indicating the establishment of a joint session; wherein the identification information of the multimedia session is a multimedia session established by the terminal in the first mobile communication network.

[0085] In a twenty-second aspect, a network-side device is provided, including a processor and a communication interface, wherein the communication interface is used to receive a registration request sent by a terminal; send an update request to a fourth network-side device according to the registration request; and receive information from the fourth network-side device regarding a second network-side device corresponding to the establishment of a multimedia session by the terminal in a first mobile communication network.

[0086] In a twentieth aspect, a network-side device is provided, including a processor and a communication interface, wherein the communication interface is used as a receiving module to receive update requests and to send information about a second network-side device corresponding to a multimedia session established by a terminal in a first mobile communication network.

[0087] In a twenty-fourth aspect, a terminal is provided, including a processor and a communication interface, wherein the communication interface is used to acquire first information of a first mobile communication network, wherein the first information is used to indicate at least one of the following: supporting multimedia service transmission through the first mobile communication network or not supporting multimedia service transmission through the first mobile communication network; supporting multimedia service transmission through a second mobile communication network or not supporting multimedia service transmission through the second mobile communication network; supporting multimedia service transmission through a third mobile communication network or not supporting multimedia service transmission through the third mobile communication network; supporting fallback to the third mobile communication network or not supporting fallback to the third mobile communication network.

[0088] In a twenty-fifth aspect, a terminal is provided, including a processor and a communication interface, wherein the communication interface is used to send a multimedia session establishment request to a network-side device of a second mobile communication network or a third mobile communication network, the establishment request including at least one of the following: identification information of the multimedia session; information for indicating the retention of the multimedia session; and information for indicating the establishment of a joint session; wherein the identification information of the multimedia session is an identifier of a multimedia session established by the terminal in the first mobile communication network.

[0089] In a twenty-sixth aspect, a readable storage medium is provided, on which a program or instructions are stored, which, when executed by a processor, implement the steps of the method described in the first aspect, or the steps of the method described in the second aspect, or the steps of the method described in the third aspect, or the steps of the method described in the fourth aspect, or the steps of the method described in the fifth aspect, or the steps of the method described in the sixth aspect, or the steps of the method described in the seventh aspect.

[0090] A twenty-seventh aspect provides a wireless communication system, including a terminal, and further including at least one of a first network-side device, a second network-side device, a third network-side device, and a fourth network-side device. The terminal is available to perform steps of the method described in the first aspect, or steps of the method described in the sixth aspect, or steps of the method described in the seventh aspect. The first network-side device is available to perform steps of the method described in the second aspect, the second network-side device is available to perform steps of the method described in the third aspect, the third network-side device is available to perform steps of the method described in the fourth aspect, and the fourth network-side device is available to perform steps of the method described in the fifth aspect.

[0091] In a twentieth aspect, a chip is provided, the chip including a processor and a communication interface coupled to the processor, the processor being configured to run a program or instructions to implement the method as described in the first aspect, or the method as described in the second aspect, or the method as described in the third aspect, or the method as described in the fourth aspect, or the method as described in the fifth aspect, or the method as described in the sixth aspect, or the method as described in the seventh aspect.

[0092] In a twenty-ninth aspect, a computer program / program product is provided, the computer program / program product being stored in a storage medium, the computer program / program product being executed by at least one processor to implement the steps of the method as described in the first aspect, the computer program / program product being executed by at least one processor to implement the steps of the method as described in the second aspect, the computer program / program product being executed by at least one processor to implement the steps of the method as described in the third aspect, the computer program / program product being executed by at least one processor to implement the steps of the method as described in the fourth aspect, the computer program / program product being executed by at least one processor to implement the steps of the method as described in the fifth aspect, the computer program / program product being executed by at least one processor to implement the steps of the method as described in the sixth aspect, and the computer program / program product being executed by at least one processor to implement the steps of the method as described in the seventh aspect.

[0093] In this embodiment, when the terminal is registered with the first mobile communication network, it performs a call operation. The call operation includes at least one of the following: initiating a first call request through a second or third mobile communication network; and sending a call response through the second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network. This allows the terminal to conduct calls through the second or third mobile communication network while the terminal is registered with the first mobile communication network, thereby improving the terminal's call performance. Attached Figure Description

[0094] Figure 1 is a block diagram of a wireless communication system applicable to an embodiment of this application;

[0095] Figure 2 is a flowchart of a call method provided in an embodiment of this application;

[0096] Figure 3 is a flowchart of another call method provided in an embodiment of this application;

[0097] Figure 4 is a flowchart of an information transmission method provided in an embodiment of this application;

[0098] Figure 5 is a flowchart of another information transmission method provided in an embodiment of this application;

[0099] Figure 6 is a flowchart of another information transmission method provided in an embodiment of this application;

[0100] Figure 7 is a flowchart of another information transmission method provided in an embodiment of this application;

[0101] Figure 8 is a flowchart of another information transmission method provided in an embodiment of this application;

[0102] Figure 9 is a schematic diagram of a call method provided in an embodiment of this application;

[0103] Figure 10 is a schematic diagram of another call method provided in an embodiment of this application;

[0104] Figure 11 is a schematic diagram of another call method provided in an embodiment of this application;

[0105] Figure 12 is a structural diagram of a communication device provided in an embodiment of this application;

[0106] Figure 13 is a structural diagram of an information transmission device provided in an embodiment of this application;

[0107] Figure 14 is a structural diagram of another information transmission device provided in an embodiment of this application;

[0108] Figure 15 is a structural diagram of another information transmission device provided in an embodiment of this application;

[0109] Figure 16 is a structural diagram of another information transmission device provided in an embodiment of this application;

[0110] Figure 17 is a structural diagram of another information transmission device provided in an embodiment of this application;

[0111] Figure 18 is a structural diagram of another information transmission device provided in an embodiment of this application;

[0112] Figure 19 is a structural diagram of a communication device provided in an embodiment of this application;

[0113] Figure 20 is a structural diagram of a terminal provided in an embodiment of this application;

[0114] Figure 21 is a structural diagram of a network-side device provided in an embodiment of this application. Detailed Implementation

[0115] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0116] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same class, not limited in number; for example, the first object can be one or more. Furthermore, "or" in this application indicates at least one of the connected objects. For example, the scope of protection for "A or B" covers at least three scenarios: Scenario 1: including A but not B; Scenario 2: including B but not A; Scenario 3: including both A and B. In addition, the terms "A and / or B," "at least one of A and B," and "at least one of A or B" also cover at least the above three scenarios. The character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0117] The term "instruction" in this application can be either a direct instruction (or explicit instruction) or an indirect instruction (or implicit instruction). A direct instruction can be understood as one in which the sender explicitly informs the receiver of specific information, the operation to be performed, or the requested result, etc., in the instruction sent. An indirect instruction can be understood as one in which the receiver determines the corresponding information based on the instruction sent by the sender, or makes a judgment and determines the operation to be performed or the requested result, etc., based on the judgment result.

[0118] It is worth noting that the technologies described in this application are not limited to Long Term Evolution (LTE) / LTE-Advanced (LTE-A) systems, but can also be used in other wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency-Division Multiple Access (SC-FDMA), or other systems. The terms "system" and "network" in this application are often used interchangeably, and the described technologies can be used with the systems and radio technologies mentioned above, as well as with other systems and radio technologies. The following description describes New Radio (NR) systems for illustrative purposes, and the term NR is used in most of the following description; however, these technologies can also be applied to systems other than NR systems, such as 6th generation (6G) radio systems. th Generation 6G communication system.

[0119] Figure 1 shows a block diagram of a wireless communication system applicable to an embodiment of this application. The wireless communication system includes a terminal 11 and a network-side device 12. The terminal 11 can be a mobile phone, tablet computer, laptop computer, notebook computer, personal digital assistant (PDA), handheld computer, netbook, ultra-mobile personal computer (UMPC), mobile internet device (MID), augmented reality (AR), virtual reality (VR) device, robot, wearable device, flight vehicle, vehicle user equipment (VUE), shipboard equipment, pedestrian user equipment (PUE), smart home (home devices with wireless communication capabilities, such as refrigerators, televisions, washing machines, or furniture), game console, personal computer (PC), ATM, or self-service machine, etc. Wearable devices include: smartwatches, smart bracelets, smart headphones, smart glasses, smart jewelry (smart bracelets, smart chains, smart rings, smart necklaces, smart anklets, smart anklets, etc.), smart wristbands, smart clothing, etc. Among these, in-vehicle devices can also be referred to as in-vehicle terminals, in-vehicle controllers, in-vehicle modules, in-vehicle components, in-vehicle chips, or in-vehicle units, etc. Terminal 11 can be any of the aforementioned terminal devices, or it can be a chip within a terminal, such as a modem chip or a system-on-chip (SoC). It should be noted that the specific type of terminal 11 is not limited in this application embodiment. Network-side device 12 can include access network devices or core network devices, wherein access network devices can also be referred to as Radio Access Network (RAN) devices, radio access network functions, or radio access network units. Access network devices can include base stations, Wireless Local Area Network (WLAN) access points (AS), or Wireless Fidelity (WiFi) nodes, etc.The term "base station" can be referred to as Node B (NB), Evolved Node B (eNB), Next Generation Node B (gNB), New Radio Node B (NR Node B), Access Point, Relay Base Station (RBS), Serving Base Station (SBS), Base Transceiver Station (BTS), Radio Base Station, Radio Transceiver, Basic Service Set (BSS), Extended Service Set (ESS), Home Node B (HNB), Home Evolved Node B, Transmit / Receive Point (TRP), or any other suitable term in the relevant field, as long as the same technical effect is achieved. The term "base station" is not limited to any specific technical terminology. It should be noted that this application embodiment only uses a base station in an NR system as an example for description and does not limit the specific type of base station.

[0120] Core network equipment, also known as core network nodes, core network functions, or core network elements, includes, but is not limited to, at least one of the following: Mobility Management Entity (MME), Access and Mobility Management Function (AMF), Session Management Function (SMF), User Plane Function (UPF), Policy Control Function (PCF), Policy and Charging Rules Function (PCRF), Edge Application Server Discovery Function (EASDF), Unified Data Management (UDM), Unified Data Repository (UDR), Home Subscriber Server (HSS), Centralized network configuration (CNC), Network Repository Function (NRF), Network Exposure Function (NEF), Local NEF (or L-NEF), and Binding Support. The core network functions include: BSF (Block Network Function), Application Function (AF), Location Management Function (LMF), Gateway Mobile Location Centre (GMLC), and Network Data Analytics Function (NWDAF). It should be noted that this application embodiment only uses core network equipment in the NR system as an example and does not limit the specific type of core network equipment. If the name of the core network equipment mentioned in this application embodiment changes in subsequent protocol versions (e.g., 6G), it will still be within the scope of protection of this application.

[0121] Optionally, the core network equipment can be implemented by one or more functional modules in a single device, or by multiple devices working together; this application does not specifically limit this. It is understood that the aforementioned functional modules can be network elements in hardware devices, software functional modules running on dedicated hardware, or virtualized functional modules instantiated on a platform (e.g., a cloud platform).

[0122] The following description, in conjunction with the accompanying drawings, details the call method, information transmission method, apparatus, and device provided in this application through some embodiments and application scenarios.

[0123] Please refer to Figure 2, which is a flowchart of a call method provided in an embodiment of this application. As shown in Figure 2, it includes the following steps:

[0124] Step 201: When the terminal is registered with the first mobile communication network, it performs a call operation, which includes at least one of the following:

[0125] Initiate the first call request through the second or third mobile communication network;

[0126] A call response is sent through a second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network.

[0127] In some implementations, the first mobile communication network includes a sixth-generation (6G) mobile communication network (hereinafter referred to as 6G network), the second mobile communication network includes a fifth-generation (5G) mobile communication network (hereinafter referred to as 5G network), and the third mobile communication network includes a fourth-generation (4G) mobile communication network (hereinafter referred to as 4G network).

[0128] In this embodiment of the application, the first mobile communication network, the second mobile communication network and the third mobile communication device are not limited to the above-mentioned first mobile communication network, second mobile communication network and third mobile communication device. For example, the first mobile communication network may be a 7th generation (7G) mobile communication network, the second mobile communication network may be a 6G mobile communication network and the third mobile communication network may be a 5G mobile communication network.

[0129] The aforementioned terminal being in a registered state on the first mobile communication network can be understood as the terminal having already completed or registered with the first mobile communication network when step 201 is executed. For example, the terminal initiated a registration process with the first mobile communication network before step 201.

[0130] The first and second call requests mentioned above are call request requests, specifically voice call request requests.

[0131] In some implementations, for multimedia services, the first call request and the second call request mentioned above may be IP Multimedia Subsystem (IMS) Invite requests.

[0132] The aforementioned terminal can support simultaneous or time-sharing connections to at least two networks. For example, the aforementioned terminal supports simultaneous or time-sharing connections to 6G+5G or 6G+4G. The feature of supporting simultaneous or time-sharing connections to at least two networks can also be called dual stack (DS), or the aforementioned DS can also be called dual steer.

[0133] In the case where a call response is sent through a second or third mobile communication network, the second call request is a call request received through the first mobile communication network before step 201 is executed.

[0134] In this embodiment, the above-described method enables the terminal to make calls via a second or third mobile communication network while it is registered with the first mobile communication network, thereby improving call performance. For example, in the early stages of 6G deployment, while the terminal is registered with 6G, it can make calls via 5G or 4G.

[0135] As an optional implementation, when the terminal is registered with the first mobile communication network, it performs a call operation, including:

[0136] The terminal performs a call operation when it is registered in the first mobile communication network and a multimedia session has been established in the first mobile communication network.

[0137] The aforementioned multimedia sessions are used to transmit multimedia services, such as IMS services.

[0138] In this embodiment, a multimedia session can also be called a Protocol Data Unit (PDU) session, such as a PDU session used to transmit IMS services, which will be referred to as an IMS PDU session; or a multimedia session can also be called a Packet Data Network (PDN) connection or a multimedia connection, etc. In this embodiment, the name of the multimedia session is not limited.

[0139] In this embodiment, it is possible to make calls through a second or third mobile communication network when the first mobile communication network is registered and a multimedia session has been established on the first mobile communication network. This can improve call performance while ensuring the performance of the terminal on the first mobile communication network.

[0140] It should be noted that, in some embodiments of this application, when performing step 201, the terminal may also have an unestablished multimedia session on the first mobile communication device.

[0141] As an optional implementation, the method further includes:

[0142] The terminal acquires first information from the first mobile communication network, wherein the first information is used to indicate at least one of the following:

[0143] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0144] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0145] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0146] It supports or does not support falling back to the third mobile communication network.

[0147] The aforementioned multimedia services can be voice multimedia services, such as IMS services, or they can be non-voice multimedia services.

[0148] Supporting fallback to the third mobile communication network can also be understood or replaced as supporting fallback to the third mobile communication network for multimedia service transmission.

[0149] Taking the first mobile communication network as 6G as an example, the first information is used to indicate at least one of the following:

[0150] Whether or not 6G-enabled voice over 6G (Vo6G) is supported or not, it can also be referred to as voice service via 6G network.

[0151] Whether or not it supports Voice over New Radio (VoNR), also known as voice service via 5G network;

[0152] Support or not support Evolved Packet System (EPS) fallback;

[0153] Whether or not it supports Voice over Long-Term Evolution (VoLTE), also known as voice service over 4G network.

[0154] In the above embodiments, the first information can be used to determine whether the first mobile communication device supports or does not support multimedia service transmission methods, so that the terminal can select the corresponding mobile communication network for making a call based on the information, thereby improving the reliability of the call.

[0155] Optionally, the terminal acquires the first information of the first mobile communication network, including:

[0156] The terminal receives a registration acceptance message sent by the network-side device of the first mobile communication network;

[0157] Wherein, the registration acceptance message includes the first information, or,

[0158] The registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports DS.

[0159] The aforementioned registration acceptance message is a registration acceptance message for a registration request sent by the terminal in the first mobile communication network.

[0160] In this embodiment, since the first information is obtained through the registration acceptance message, additional messages can be avoided, thus saving transmission overhead. Furthermore, since the registration acceptance message can also instruct the first mobile communication network to support DS, the terminal can make calls to the first mobile communication device via either the second or third mobile communication network.

[0161] In some implementations, the terminal may also default to the first mobile communication network supporting DS.

[0162] It should be noted that, in this embodiment of the application, the terminal obtains the first information from the registration acceptance message as an example. The terminal may also obtain the first information from other messages, such as the mobility location update acceptance message, the service request acceptance message, etc.

[0163] Optionally, the call operation includes at least one of the following:

[0164] Under the first condition, a first call request is initiated through the second mobile communication network;

[0165] Under the second condition, a first call request is initiated through the third mobile communication network;

[0166] Under the first condition, a call response is sent through the second mobile communication network;

[0167] Under the second condition, a call response is sent through the third mobile communication network;

[0168] The first condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0169] The second condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0170] In this embodiment, different mobile communication networks can be selected for calls based on different conditions. For example, under the first condition, a first call request or call response can be initiated through a second mobile communication network, and under the second condition, a first call request or call response can be initiated through a third mobile communication network, thereby improving the reliability of the call.

[0171] As an optional implementation, the method further includes at least one of the following:

[0172] The terminal initiates the registration process through the second mobile communication network or the third mobile communication network;

[0173] The terminal establishes a multimedia session on the second mobile communication network or the third mobile communication network.

[0174] The registration process and the establishment of the multimedia session can be performed before step 201, before the terminal registers with the first mobile communication network, or simultaneously with step 201.

[0175] In this embodiment, since the registration process is initiated through the second mobile communication network or the third mobile communication network, it is beneficial for the terminal to make calls through the second mobile communication network or the third mobile communication network, thereby improving the reliability of the call.

[0176] In this embodiment, since a multimedia session is established on the second mobile communication network or the third mobile communication network, it is beneficial for the terminal to make calls through the second mobile communication network or the third mobile communication network, thereby improving the reliability of the call.

[0177] Optionally, the terminal initiates a registration process through the second mobile communication network or the third mobile communication network, including at least one of the following:

[0178] Under the third condition, the terminal initiates the registration process through the second mobile communication network;

[0179] Under the fourth condition, the terminal initiates the registration process through the third mobile communication network;

[0180] The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0181] The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0182] Among them, the third condition mentioned above can be the same as the first condition mentioned above, and the fourth condition mentioned above can be the same as the second condition mentioned above.

[0183] In this implementation, different mobile communication networks can be selected to initiate the registration process based on different conditions. For example, under the third condition, the registration process can be initiated through the second mobile communication network, and under the fourth condition, the registration process can be initiated through the third mobile communication network, thereby improving the reliability of calls. Taking the first mobile communication network as a 6G network as an example, the registration process includes:

[0184] When the 6G network does not support Vo6G but the 5G network supports VoNR, the terminal initiates the registration process on the 5G network.

[0185] When the 6G network does not support Vo6G, the 5G network does not support VoNR, and the 5G network supports EPS fallback; or, the 6G network does not support Vo6G, the 5G network does not support VoNR, and the 5G network does not support EPS fallback, but the 4G network supports VoLTE; or, the 6G network does not support Vo6G, the 5G network does not support VoNR, but the 4G network supports VoLTE, the terminal initiates the registration process on the 4G network.

[0186] Optionally, the terminal establishes a multimedia session on the second mobile communication network or the third mobile communication network, including at least one of the following:

[0187] Under the third condition, a multimedia session is established on the second mobile communication network;

[0188] Under the fourth condition, a multimedia session is established on the third mobile communication network;

[0189] The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0190] The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0191] In this implementation, different mobile communication networks can be selected to establish multimedia sessions based on different conditions. For example, a multimedia session can be established on a second mobile communication network under a third condition, and on a third mobile communication network under a fourth condition, thereby improving call reliability. Taking the first mobile communication network as a 6G network as an example, the terminal can establish a multimedia session (such as an IMS PDU session or PDN connection) on 5G / 4G as follows:

[0192] When the 6G network does not support Vo6G but the 5G network supports VoNR, the terminal establishes an IMS PDU session on the 5G network.

[0193] When the 6G network does not support Vo6G, the 5G network does not support VoNR, and the 5G network supports EPS fallback; or, the 6G network does not support Vo6G, the 5G network does not support VoNR, and the 5G network does not support EPS fallback, but the 4G network supports VoLTE; or, the 6G network does not support Vo6G, the 5G network does not support VoNR, but the 4G network supports VoLTE, the terminal establishes an IMS PDN connection on the 4G network.

[0194] Optionally, the call operation includes one of the following:

[0195] The terminal initiates a call request through a multimedia session established in the second mobile communication network;

[0196] The terminal initiates a call request through a multimedia session established on the third mobile communication network;

[0197] The terminal sends a call response through a multimedia session established in the second mobile communication network;

[0198] The terminal sends a call response through a multimedia session established on the third mobile communication network.

[0199] In this implementation, call requests or responses can be initiated through established multimedia sessions to improve call reliability. For example, call requests or responses can be initiated using or through a 5G IMS PDU session or a 4G IMS PDN connection.

[0200] Optionally, the terminal establishes a multimedia session on the second mobile communication network or the third mobile communication network, including:

[0201] The terminal sends a multimedia session establishment request to the network-side device of the second mobile communication network or the third mobile communication network, the establishment request including at least one of the following:

[0202] Identification information for multimedia sessions;

[0203] Information used to indicate the retention of multimedia sessions;

[0204] Information used to indicate the establishment of a joint session;

[0205] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0206] The above-mentioned request can be a session creation request or a PDN connectivity request.

[0207] The identification information of the aforementioned multimedia session can be the identification information of the session established by the terminal in the first mobile communication network, such as: PDU session ID.

[0208] Because it includes the identification information of the aforementioned multimedia session, a session with the same IP address as the multimedia session can be established in the second or third mobile communication network to ensure IP continuity and thus service continuity. For example, when establishing an IMS PDU session or IMS PDN connection in 5G or 4G, the IP address is the same as that of the 6G IMS PDU session.

[0209] The information mentioned above for indicating the retention of multimedia sessions can indicate the retention of multimedia sessions of the terminal, but may not specifically indicate which multimedia sessions need to be retained. For example, the receiver may understand it as indicating the retention of all or part of the multimedia sessions of the terminal; or the information mentioned above for indicating the retention of multimedia sessions can indicate the retention of the multimedia sessions corresponding to the above-mentioned identification information.

[0210] It should be noted that "retain" can be understood or replaced with: maintain, continue, keep, preserve, reuse, or save.

[0211] The information provided above, indicating the retention of multimedia sessions, allows the retention of other multimedia sessions when a new multimedia session is established. This prevents the multimedia session from being deleted, which would require the terminal to re-establish the corresponding multimedia session after the call ends, thus saving transmission overhead.

[0212] The aforementioned joint session can be a joint session of multimedia sessions established by the terminal in different mobile communication networks. That is, the joint session includes multimedia sessions established by the terminal in multiple mobile communication networks, such as the multimedia session established by the terminal in the first mobile communication network, and the multimedia session established in the second or third mobile communication network.

[0213] The aforementioned joint session allows multiple sessions to share the same IP address, ensuring IP continuity and thus service continuity. It also preserves sessions established by the terminal in the first mobile communication network.

[0214] It should be noted that the term "joint session" can be understood or replaced as: multi-access (MA) session, dual-protocol stack session, or dual-redirection session.

[0215] A joint session can also be understood as a session that has access legs in different mobile communication networks. For example, a joint session may have 6G and 5G access legs; or, a joint session may have 6G and 4G access legs.

[0216] In some implementations, the aforementioned establishment request may also indicate that the multimedia session corresponding to the aforementioned identification information is a session established by the terminal in the first mobile communication network. This indication may be provided in the aforementioned identification information or through additional information, so that the network-side device of the second or third mobile communication network knows that the currently established multimedia session is a call conducted in conjunction with the first mobile communication network.

[0217] Optionally, the method further includes at least one of the following:

[0218] When a call ends, the terminal initiates a multimedia session release request on the second mobile communication network or the third mobile communication network.

[0219] When a call ends, the terminal initiates a deregistration process on the second mobile communication network or the third mobile communication network.

[0220] When a call ends, the terminal initiates a modification process through the first mobile communication network. The modification process is used to modify the multimedia session established by the terminal on the first mobile communication network to an available state.

[0221] Specifically, modifying the multimedia session established by the terminal in the first mobile communication network to an available state can be based on the above-described implementation method of retaining the multimedia session (i.e., modifying the multimedia session to an unavailable state), by modifying the multimedia session to an available state.

[0222] The aforementioned release request for a multimedia session initiated in the second or third mobile communication network can be sent to the network-side device of the second or third mobile communication network to release the session resources established by the terminal in the second or third mobile communication network, thereby conserving resources. For example, after a call ends, the terminal initiates a release request for an IMS PDU session or PDN connection in 5G or 4G.

[0223] The aforementioned deregistration process initiated in the second or third mobile communication network can be achieved by the terminal sending a deregistration request message to the network-side device of the second or third mobile communication network to request deregistration in order to free up more resources. For example, the terminal can initiate a deregistration (deregister, or detach) process in 5G or 4G.

[0224] The aforementioned modification process initiated through the first mobile communication network can involve sending a modification request message to the network-side device of the first mobile communication network to modify the multimedia session established by the terminal on the first mobile communication network into an available state. This allows the terminal to transmit services through the session on the first mobile communication network, thereby improving the terminal's transmission performance. For example, in a 6G network, the terminal can modify the 6G IMS PDU session through a PDU session modification process, making the 6G IMS PDU session available, such as in an active state (activated, active, or normal state).

[0225] In this embodiment, when the terminal is registered with the first mobile communication network, it performs a call operation. The call operation includes at least one of the following: initiating a first call request through a second or third mobile communication network; and sending a call response through the second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network. This allows the terminal to conduct calls through the second or third mobile communication network while the terminal is registered with the first mobile communication network, thereby improving the terminal's call performance.

[0226] Please refer to Figure 3, which is a flowchart illustrating an information transmission method provided in an embodiment of this application. As shown in Figure 3, the method includes the following steps:

[0227] Step 301: The first network-side device sends first information to the terminal. The first network-side device is a network-side device of the first mobile communication network. The first information is used to indicate at least one of the following:

[0228] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0229] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0230] It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0231] It supports or does not support falling back to the third mobile communication network.

[0232] The first information mentioned above is described in the corresponding description of the embodiment shown in Figure 2, and will not be repeated here.

[0233] The aforementioned first network-side equipment may be the core network equipment of the first mobile communication network, such as an AMF, specifically a 6G AMF, or the access network equipment of the first mobile communication network, such as a base station, specifically a 6G base station.

[0234] In this embodiment, the first information can indicate the mode of multimedia service transmission supported by the first mobile communication network, so that when the terminal is in the registered state of the first mobile communication network, it can select the second or third mobile communication network to make a call based on the first information, thereby improving the call performance of the terminal.

[0235] Optionally, the first network-side device sends first information to the terminal, including:

[0236] The first network-side device sends a registration acceptance message to the terminal, wherein the registration acceptance message includes the first information, or the registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

[0237] It should be noted that this embodiment is an implementation of the network-side device of the first mobile communication network corresponding to the embodiment shown in FIG2. For the specific implementation, please refer to the relevant description of the embodiment shown in FIG2. In order to avoid repeated description, this embodiment will not be repeated.

[0238] Please refer to Figure 4, which is a flowchart illustrating another information transmission method provided in an embodiment of this application. As shown in Figure 4, the method includes the following steps:

[0239] Step 401: The second network-side device receives a request to establish a multimedia session;

[0240] The establishment request includes at least one of the following:

[0241] Identification information for multimedia sessions;

[0242] Information used to indicate the retention of multimedia sessions;

[0243] Information used to indicate the establishment of a joint session;

[0244] The identification information of the multimedia session refers to the multimedia session established by the terminal in the first mobile communication network.

[0245] The aforementioned second network-side equipment can be a device or network element that is jointly deployed by multiple mobile communication networks, such as a network element jointly deployed by 6G, 5G and 4G (6G SMF+5G SMF+PGW-C), a network element jointly deployed by 6G and 5G (6G SMF+5G SMF), or a network element jointly deployed by 6G and 4G (6G SMF+PGW-C), etc.

[0246] Alternatively, the aforementioned second network-side device can be an SMF.

[0247] The aforementioned second network-side device may receive a multimedia session establishment request from a terminal or from a network-side device of a second or third mobile communication network.

[0248] The above-mentioned request can be referred to the corresponding description of the embodiment shown in Figure 2, which will not be repeated here.

[0249] In this embodiment, since the above-mentioned establishment request has been received, the second network-side device can respond to the above-mentioned request so that the terminal can make calls better and improve the terminal's call performance.

[0250] Optionally, the method further includes at least one of the following:

[0251] The second network-side device assigns the address information of the multimedia session corresponding to the identification information to the terminal;

[0252] The second network-side device retains the multimedia session corresponding to the identification information;

[0253] The second network-side device sets the multimedia session corresponding to the identification information to an unavailable state;

[0254] The second network-side device establishes a joint session.

[0255] Wherein, at least one of the above refers to the response behavior of the second network-side device to the establishment request, that is, the execution of at least one of the above based on the establishment request.

[0256] The second network-side device may assign the address information of the multimedia session corresponding to the identification information to the terminal by determining the multimedia session based on the identification information of the multimedia session and assigning the IP address information of the multimedia session to the terminal.

[0257] The address information corresponding to the identification information allocated by the second network-side device can be the address of a multimedia session established by the terminal in the second or third mobile communication network. That is, multiple media sessions described in the embodiment shown in Figure 2 use the same IP address. Specifically, after allocating the address information, the second network-side device sends the address information to the network-side device of the second or third mobile communication network, so that the multimedia sessions established by the network-side device of the second or third mobile communication network use the address information.

[0258] The multimedia sessions corresponding to the aforementioned retained identification information are described in the corresponding description of the embodiment shown in Figure 2, and will not be repeated here.

[0259] The second network-side device sets the multimedia session corresponding to the identification information to an unavailable state. The unavailable state can be understood or replaced as a deactive or inactive state.

[0260] The establishment of the joint session is described in the corresponding description of the embodiment shown in Figure 2, and will not be repeated here.

[0261] It should be noted that this embodiment is an implementation of the second network-side device corresponding to the embodiment shown in FIG2. For the specific implementation, please refer to the relevant description of the embodiment shown in FIG2. In order to avoid repeated description, this embodiment will not be repeated.

[0262] Please refer to Figure 5, which is a flowchart illustrating another information transmission method provided in this application embodiment. As shown in Figure 4, it includes the following steps:

[0263] Step 501: The third network-side device receives the registration request sent by the terminal;

[0264] Step 502: The third network-side device sends an update request to the fourth network-side device according to the registration request;

[0265] Step 503: The third network-side device receives information from the fourth network-side device regarding the second network-side device corresponding to the establishment of a multimedia session by the terminal in the first mobile communication network.

[0266] The aforementioned third network-side equipment can be a network-side device of the second or third mobile communication network, such as the core network equipment of the second or third mobile communication network, such as MME or AMF.

[0267] The aforementioned fourth network-side device may be another network-side device of the second or third mobile communication network, such as a UDM, or the aforementioned fourth network-side device may be a network-side device shared by multiple mobile communication networks.

[0268] The second network-side device mentioned above is the second network-side device in the embodiment shown in FIG4.

[0269] The above registration request is a registration request initiated by the terminal in a second or third mobile communication network.

[0270] The aforementioned update request is used to request information about the second network-side device, such as information about the second network-side device used in a multimedia session established by the terminal in the first mobile communication network, or information about the 6G SMF+5G SMF+PGW-C used in an IMS PDU session established by the terminal in 6G.

[0271] In some implementations, the update request may be a location update request.

[0272] In this embodiment, by obtaining information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network, relevant call operations can be provided to the terminal based on the information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network, thereby improving the call performance of the terminal.

[0273] Optionally, the method further includes:

[0274] The third network-side device receives a multimedia session establishment request sent by the terminal, the establishment request including at least one of the following:

[0275] Identification information for multimedia sessions;

[0276] Information used to indicate the retention of multimedia sessions;

[0277] Information used to indicate the establishment of a joint session;

[0278] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0279] The above-mentioned request can be referred to the corresponding description of the embodiment shown in Figure 2, which will not be repeated here.

[0280] Optionally, the method further includes:

[0281] The third network-side device sends an establishment request to the second network-side device, the establishment request including at least one of the following:

[0282] Identification information for multimedia sessions;

[0283] Information used to indicate the retention of multimedia sessions;

[0284] Information used to indicate the establishment of a joint session;

[0285] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0286] The above-mentioned request can be referred to the corresponding description of the embodiments shown in Figure 2 or Figure 4, which will not be repeated here.

[0287] It should be noted that this embodiment is an implementation of the third network-side device corresponding to the embodiment shown in Figure 2. For the specific implementation, please refer to the relevant description of the embodiment shown in Figure 2. In order to avoid repeated description, this embodiment will not be repeated.

[0288] Please refer to Figure 6, which is a flowchart illustrating another information transmission method provided in an embodiment of this application. As shown in Figure 6, the method includes the following steps:

[0289] Step 601: The fourth network-side device receives the update request;

[0290] Step 602: The fourth network-side device sends information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network.

[0291] The aforementioned fourth network-side device may be the core network device of the second or third mobile communication network, or the core network device corresponding to multiple mobile communication networks, such as UDM.

[0292] The aforementioned fourth network-side device stores or pre-acquires information about the second network-side device corresponding to the establishment of a multimedia session by a terminal in the first mobile communication network.

[0293] In this embodiment, since the sending terminal establishes a multimedia session with the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network, it can support providing calls to the terminal based on the information of the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network, thereby improving the terminal's call performance.

[0294] It should be noted that this embodiment is an implementation of the fourth network-side device corresponding to the embodiment shown in Figure 2 or Figure 5. For the specific implementation, please refer to the relevant description of the embodiment shown in Figure 2 or Figure 5. In order to avoid repeated description, this embodiment will not be repeated.

[0295] Please refer to Figure 7, which is a flowchart illustrating another information transmission method provided in an embodiment of this application. As shown in Figure 7, it includes the following steps:

[0296] Step 701: The terminal obtains first information from the first mobile communication network, wherein the first information is used to indicate at least one of the following:

[0297] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0298] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0299] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0300] It supports or does not support falling back to the third mobile communication network.

[0301] The first information mentioned above is described in the corresponding description of the embodiment shown in Figure 2, and will not be repeated here.

[0302] In this embodiment, by acquiring the first information, the terminal can select the corresponding mobile communication network for making a call based on the first information, thereby improving the terminal's call performance.

[0303] It should be noted that the terminal described in this embodiment can perform the behavior of all terminals in the embodiment shown in Figure 2, which will not be elaborated here.

[0304] Please refer to Figure 8, which is a flowchart illustrating another information transmission method provided in an embodiment of this application. As shown in Figure 8, it includes the following steps:

[0305] Step 801: The terminal sends a multimedia session establishment request to the network-side device of the second or third mobile communication network, the establishment request including at least one of the following:

[0306] Identification information for multimedia sessions;

[0307] Information used to indicate the retention of multimedia sessions;

[0308] Information used to indicate the establishment of a joint session;

[0309] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0310] The above-mentioned request can be referred to the corresponding description of the embodiment shown in Figure 2, which will not be repeated here.

[0311] In this embodiment, the above-mentioned establishment request enables the network-side device of the second or third mobile communication network to establish a corresponding session, thereby improving the communication performance of the terminal.

[0312] It should be noted that the terminal described in this embodiment can perform the behavior of all terminals in the embodiment shown in Figure 2, which will not be elaborated here.

[0313] The following examples, using a first mobile communication network of 6G, a second mobile communication network of 5G, and a third mobile communication network of 4G, illustrate the method provided in this application through multiple embodiments:

[0314] Example 1:

[0315] This embodiment mainly describes the UE registration process in a 6G network.

[0316] The main idea of ​​this embodiment is: when the UE registers on the 6G network, the 6G network notifies the UE of the voice methods it supports. When the UE receives a voice call request on the 6G network, or when the UE needs to initiate a voice call request, the UE sends an IMS message through the 5G or 4G network.

[0317] The specific signaling flow is shown in Figure 9. In Figure 9, 6G SMF+5G SMF+PGW-C is a network element co-located with 6G, 5G and 4G. In the case of 6G+5G, it can be replaced with 6G SMF+5G SMF; in the case of 6G+4G, it can be replaced with 6G SMF+PGW-C. 6G UPF+5G UPF+PGW-U is a network element co-located with 6G, 5G and 4G. In the case of 6G+5G, it can be replaced with 6G UPF+5G UPF; in the case of 6G+4G, it can be replaced with 6GUPF+PGW-U.

[0318] As shown in Figure 9, the following steps are included:

[0319] Step 1. UE-1 sends a registration request on the 6G network, which includes indication information that the UE supports DS (dual stack or dual steer).

[0320] Step 2. The AMF sends a registration acceptance message to the UE, which includes indications of network support for DS and network-supported voice methods, including at least one of the following:

[0321] Whether or not Vo6G is supported can also be referred to as conducting voice services through a 6G network.

[0322] Whether or not VoNR is supported, it can also be referred to as conducting voice services through a 5G network.

[0323] Whether EPS fallback is supported or not can also be referred to as providing voice services by falling back to the 4G network.

[0324] Whether or not VoLTE is supported can also be referred to as providing voice services through a 4G network;

[0325] Step 3. The UE establishes a PDU session for transmitting IMS services through the 6G network;

[0326] In this application embodiment, the PDU session used for transmitting IMS services is hereinafter referred to as the IMS PDU session. The PDU session is a 5G concept, while the PDN connection is a 4G concept. In 6G, it can be called a 6G PDU session, or a new name defined for 6G in subsequent protocols.

[0327] In this context, the 5G PDU session used for transmitting IMS services will be referred to as the IMS PDU session or 5G IMS PDU session, and the 4G PDN connection used for transmitting IMS services will be referred to as the IMS PDN connection.

[0328] Step 4. The UE registers with IMS via a 6G IMS PDU session.

[0329] For cases where the UE initiates a calling (MO call):

[0330] Step 5. When a user of UE-1 needs to initiate a call, for example, by opening the dialer interface.

[0331] Step 6 (optional). The UE initiates the registration process via the 5G / 4G network.

[0332] In this step, the UE initiates a registration process within the 5G or 4G network based on the voice methods supported by the network received in step 2. For example:

[0333] When the network does not support Vo6G but supports VoNR, the UE initiates the registration process in 5G.

[0334] When the network does not support Vo6G or VoNR, but supports EPS fallback; or when the network does not support Vo6G, VoNR, or EPS fallback, but supports VoLTE; or when the network does not support Vo6G or VoNR, but supports VoLTE, the UE initiates the registration process in 4G.

[0335] It should be noted that the UE can register for 5G or 4G networks immediately after completing 6G network registration; or, the UE can register for 5G or 4G networks only when it needs to make a call.

[0336] Step 7. UE-1 establishes an IMS PDU session or PDN connection in 5G / 4G according to the network's instructions on supported voice modes, for example:

[0337] When the network does not support Vo6G but supports VoNR, the UE establishes an IMS PDU session in 5G.

[0338] When the network does not support Vo6G or VoNR, but supports EPS fallback; or when the network does not support Vo6G, VoNR, or EPS fallback, but supports VoLTE; or when the network does not support Vo6G or VoNR, but supports VoLTE, the UE establishes an IMS PDN connection in 4G.

[0339] The specific establishment method is described in Example 2 or Example 3.

[0340] It should be noted that the UE can immediately register for 5G or 4G network, establish a 5G IMS PDU session or PDN connection after completing 6G network registration; or, the UE can register for 5G or 4G network, establish a 5G IMS PDU session or PDN connection when it needs to make a call.

[0341] Step 8. UE-1 initiates an IMS Invite request using a 5G IMS PDU session or a 4G IMS PDN connection.

[0342] For the case where the UE receives a call request (MT call):

[0343] Step 9. UE-1 receives an IMS Invite request via a 6G IMS PDU session.

[0344] Step 10 (optional). The UE performs the 5G / 4G registration process (same as step 6).

[0345] Step 11. UE-1 establishes an IMS PDU session or PDN connection in 5G / 4G according to the network's instructions on supported voice modes (same as step 7).

[0346] Step 12. The UE sends a response message via a 5G IMS PDU session or a 4G IMS PDN connection.

[0347] It should be noted that steps 5-8 and 9-12 are two parallel steps, not steps that must be executed in sequence.

[0348] The solution in this embodiment allows the UE to know the information about the 6G network's support for voice, and based on this information, determine whether to initiate or respond to IMS signaling using the 5G or 4G network.

[0349] Example 2:

[0350] In this embodiment, the UE establishing a PDU session or PDN connection in the 5G / 4G network represents a 6G PDU session. Specifically, it is a supplementary scheme to Embodiment 1, describing how to establish an IMS PDU session or PDN connection in 5G or 4G. The specific signaling is shown in Figure 10, which uses 4G as an example and can be extended to 5G, including the following steps:

[0351] Step 1. UE-1 establishes an IMS PDU session on 6G.

[0352] Step 2. UE-1 initiates a registration request on 4G.

[0353] Step 3. The MME sends an Update Location request to the UDM.

[0354] Step 4. UDM sends an Update Location ACK to MME, which contains information about the 6G SMF+5G SMF+PGW-C used by UE-1 in the IMS PDU session established on 6G.

[0355] Step 5. The MME replies to the UE-1 with a registration confirmation message.

[0356] Step 6. UE-1 needs to initiate a call or UE-1 needs to receive a call request (corresponding to step 5 or step 9 in Figure 2).

[0357] It should be noted that steps 2-5 can also be performed after step 6, that is, when the user needs to make or receive a call, registration can be performed on 5G or 4G.

[0358] Step 7. UE-1 initiates a PDN connectivity request, which includes: IMS Access Point Name (APN), request type = handover, Protocol Configuration Option (PCO), wherein the PCO contains first indication information, second indication information, and PDU session ID;

[0359] The first indication information is used to indicate the PDU session corresponding to the retained PDU session ID, for example, it can be a keep indication;

[0360] The second indication information is used to indicate that the PDU session ID is the ID of a 6G PDU session, for example, 6G indication.

[0361] The second indication information can be a separate indication or part of the PDU session ID.

[0362] Step 8. Based on the APN and the information received in Step 4, the MME selects 6G SMF+5G SMF+PGW-C.

[0363] Step 9. The MME sends a create session request to the selected 6G SMF+5G SMF+PGW-C, which contains the content carried in step 7.

[0364] Step 10. 6G SMF+5G SMF+PGW-C selects a 6G PDU session based on the second indication information in the PCO and the PDU session ID, and assigns an IP address for the 6G PDU session to the UE.

[0365] Step 11.6G SMF+5G SMF+PGW-C sends a response message to the MME, carrying the IP address.

[0366] Step 12. The MME sends a response message to UE-1, carrying the IP address.

[0367] Step 13.6G SMF+5G SMF+PGW-C retains the 6G PDU session according to the first instruction information (without initiating the deletion process).

[0368] Optionally, the 6G IMS PDU session may be in an unavailable state, such as a deactivate state or an inactive state.

[0369] After the call ends, the UE may, optionally, initiate a release request for the IMS PDU session or PDN connection on 5G or 4G, or the UE may initiate a deregister (or detach) procedure on 5G or 4G.

[0370] The UE modifies the process through the PDU session in 6G, and the 6G IMS PDU session is in an available state, for example, in an activated state or an active state.

[0371] The solution in this embodiment can ensure that when establishing an IMS PDU session or IMS PDN connection in 5G or 4G, the IP address is the same as that of the 6G IMS PDU session, and the 6G IMS PDU session is not released.

[0372] Example 3:

[0373] This embodiment is a supplementary solution to Embodiment 1, and is parallel to Embodiment 2, providing another solution. It mainly describes how the UE establishes a PDU session or PDN connection in the 5G / 4G network and forms a joint session with the 6G PDU session. The specific signaling is shown in Figure 11, which includes the following steps:

[0374] Steps 1-6 are the same as steps 1-6 in Example 2a.

[0375] Step 7. UE-1 initiates a PDN connectivity request, which includes IMS APN, request type = handover, PCO, and the PCO contains third indication information, second indication information, and PDU session ID.

[0376] The third indication information is used to establish a joint session between the newly established PDN connection and the PDU session corresponding to the PDU session ID. For example, it can be a multi-access PDU indication, a dual-stack PDU indication, or a dual-steer PDU indication.

[0377] The second instruction information is the same as the second instruction information in Embodiment 2.

[0378] Step 8. Based on the APN and the information received in Step 4, the MME selects 6G SMF+5G SMF+PGW-C.

[0379] Step 9. The MME sends a session creation request to the selected 6G SMF+5G SMF+PGW-C, which contains the content carried in step 7.

[0380] Step 10. The 6G SMF+5G SMF+PGW-C selects a 6G PDU session based on the second indication information in the PCO and the PDU session ID, and assigns an IP address for the 6G PDU session to the UE.

[0381] Step 11.6G SMF+5G SMF+PGW-C sends a response message to the MME, carrying the IP address.

[0382] Step 12. The MME sends a response message to UE-1, carrying the IP address.

[0383] 13.6G SMF+5G SMF+PGW-C establishes a joint session for the 6G PDU session and the 4G PDN based on the second instruction information.

[0384] After the call ends, the UE may, optionally, initiate a release request for the IMS PDU session or PDN connection on 5G or 4G, or the UE may initiate a deregister (or detach) procedure on 5G or 4G.

[0385] The solution in this embodiment can ensure that the IP address of the established federated session is the same as that of the 6G IMS PDU session, and prevent the 6G IMS PDU session from being released.

[0386] The call method provided in this application can be executed by a call device. This application uses a call device executing the call method as an example to illustrate the call device provided in this application.

[0387] The information transmission method provided in this application can be executed by an information transmission device. This application uses an information transmission device executing the information transmission method as an example to illustrate the information transmission device provided in this application.

[0388] This application provides a calling device. As an example, the calling device can be a communication device or a component within a communication device, such as a chip. The communication device can be a terminal, a network-side device, or a server, etc. Exemplarily, the terminal can be, but is not limited to, the type of terminal 11 listed above, and the network-side device can be, but is not limited to, the type of network-side device 12 listed above. This application does not impose specific limitations on these aspects.

[0389] This application provides an information transmission device. As an example, the information transmission device may be a communication device or a component within a communication device, such as a chip. The communication device may be a terminal, a network-side device, or a server, etc. Exemplarily, the terminal may include, but is not limited to, the type of terminal 11 listed above, and the network-side device may include, but is not limited to, the type of network-side device 12 listed above. This application does not impose specific limitations.

[0390] A communication device or information transmission device includes a receiving module, a transmitting module, and a processing module. These modules can be implemented in software or hardware. When implemented in hardware, the processing module can be implemented by a processor. For example, the processor can include general-purpose processors, special-purpose processors, such as a Central Processing Unit (CPU), microprocessor, Digital Signal Processor (DSP), Artificial Intelligence (AI) processor, Graphics Processing Unit (GPU), Application Specific Integrated Circuit (ASIC), Network Processor (NP), Field Programmable Gate Array (FPGA), or other programmable logic devices, gate circuits, transistors, discrete hardware components, etc. The receiving and transmitting modules can be implemented by a communication interface, which can include one or more of the following: transceiver, pins, circuits, bus, radio frequency unit, etc.

[0391] Specifically, referring to Figure 12, when the communication device is a terminal or a component within a terminal, the communication device 1200 includes:

[0392] Processing module 1201 is configured to perform a call operation when the first mobile communication network is in a registered state, the call operation including at least one of the following:

[0393] Initiate the first call request through the second or third mobile communication network;

[0394] A call response is sent through a second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network.

[0395] Optionally, the processing module 1201 is used to perform a call operation when the first mobile communication network is in a registered state and a multimedia session is established on the first mobile communication network.

[0396] Optionally, the device further includes:

[0397] The receiving module is configured to acquire first information from the first mobile communication network, wherein the first information is used to indicate at least one of the following:

[0398] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0399] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0400] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0401] It supports or does not support falling back to the third mobile communication network.

[0402] Optionally, obtaining the first information of the first mobile communication network includes:

[0403] Receive the registration acceptance message sent by the network-side device of the first mobile communication network;

[0404] Wherein, the registration acceptance message includes the first information, or,

[0405] The registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

[0406] Optionally, the call operation includes at least one of the following:

[0407] Under the first condition, a first call request is initiated through the second mobile communication network;

[0408] Under the second condition, a first call request is initiated through the third mobile communication network;

[0409] Under the first condition, a call response is sent through the second mobile communication network;

[0410] Under the second condition, a call response is sent through the third mobile communication network;

[0411] The first condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0412] The second condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0413] Optionally, the device further includes:

[0414] The sending module is used to initiate a registration process through the second mobile communication network or the third mobile communication network;

[0415] And / or,

[0416] The processing module is also used to establish a multimedia session on the second mobile communication network or the third mobile communication network.

[0417] Optionally, the registration process initiated through the second mobile communication network or the third mobile communication network includes at least one of the following:

[0418] Under the third condition, the registration process is initiated through the second mobile communication network;

[0419] Under the fourth condition, the registration process is initiated through the third mobile communication network;

[0420] The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0421] The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0422] Optionally, establishing a multimedia session in the second mobile communication network or the third mobile communication network includes at least one of the following:

[0423] Under the third condition, a multimedia session is established on the second mobile communication network;

[0424] Under the fourth condition, a multimedia session is established on the third mobile communication network;

[0425] The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0426] The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0427] Optionally, the call operation includes one of the following:

[0428] A call request is initiated through a multimedia session established on the second mobile communication network;

[0429] Initiate a call request through a multimedia session established on the third mobile communication network;

[0430] A call response is sent through a multimedia session established on the second mobile communication network;

[0431] Call responses are sent through a multimedia session established on the third mobile communication network.

[0432] Optionally, establishing a multimedia session in the second mobile communication network or the third mobile communication network includes:

[0433] Sending a multimedia session establishment request to a network-side device of the second mobile communication network or the third mobile communication network, the establishment request including at least one of the following:

[0434] Identification information for multimedia sessions;

[0435] Information used to indicate the retention of multimedia sessions;

[0436] Information used to indicate the establishment of a joint session;

[0437] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0438] Optionally, the transmitting module included in the device is further configured to perform at least one of the following:

[0439] If the call ends, a request to release the multimedia session is initiated on the second mobile communication network or the third mobile communication network;

[0440] If the call ends, a deregistration process is initiated on the second mobile communication network or the third mobile communication network;

[0441] When the call ends, a modification process is initiated through the first mobile communication network. The modification process is used to modify the multimedia session established by the terminal on the first mobile communication network to an available state.

[0442] Optionally, the first mobile communication network includes a 6G mobile communication network, the second mobile communication network includes a 5G mobile communication network, and the third mobile communication network includes a 4G mobile communication network.

[0443] The aforementioned communication device can improve the call performance of the terminal.

[0444] The communication device provided in this application embodiment can implement the various processes implemented in the method embodiment of FIG2 and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0445] Referring to Figure 13, when the information transmission device is a network-side device or a component within a network-side device, the information transmission device 1300 includes:

[0446] The sending module 1301 is used to send first information to the terminal. The network-side device corresponding to the device is a network-side device of a first mobile communication network. The first information is used to indicate at least one of the following:

[0447] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0448] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0449] It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0450] It supports or does not support falling back to the third mobile communication network.

[0451] Optionally, sending the first information to the terminal includes:

[0452] Send a registration acceptance message to the terminal, wherein the registration acceptance message includes the first information, or the registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

[0453] The aforementioned information transmission device can improve the terminal's call performance.

[0454] The communication device provided in this application embodiment can implement the various processes implemented in the method embodiment of FIG3 and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0455] Referring to Figure 14, when the information transmission device is a network-side device or a component within a network-side device, the information transmission device 1400 includes:

[0456] The receiving module 1401 is used to receive a multimedia session establishment request;

[0457] The establishment request includes at least one of the following:

[0458] Identification information for multimedia sessions;

[0459] Information used to indicate the retention of multimedia sessions;

[0460] Information used to indicate the establishment of a joint session;

[0461] The identification information of the multimedia session refers to the multimedia session established by the terminal in the first mobile communication network.

[0462] Optionally, the device further includes a processing module, the processing module being used for at least one of the following:

[0463] Assign address information for the multimedia session corresponding to the identification information to the terminal;

[0464] The multimedia session corresponding to the identification information is retained;

[0465] Set the multimedia session corresponding to the identification information to an unavailable state;

[0466] Establish a joint session.

[0467] The aforementioned information transmission device can improve the terminal's call performance.

[0468] The communication device provided in this application embodiment can implement the various processes implemented in the method embodiment of FIG4 and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0469] Referring to Figure 15, when the information transmission device is a network-side device or a component within a network-side device, the information transmission device 1500 includes:

[0470] The receiving module 1501 is used to receive the registration request sent by the terminal;

[0471] Sending module 1502 is used to send an update request to the fourth network-side device according to the registration request;

[0472] The receiving module 1501 is also used to receive information from the fourth network-side device regarding the second network-side device corresponding to the establishment of a multimedia session by the terminal in the first mobile communication network.

[0473] Optionally, the receiving module is further configured to receive a multimedia session establishment request sent by the terminal, the establishment request including at least one of the following:

[0474] Identification information for multimedia sessions;

[0475] Information used to indicate the retention of multimedia sessions;

[0476] Information used to indicate the establishment of a joint session;

[0477] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0478] Optionally, the sending module is further configured to send a creation request to the second network-side device, the creation request including at least one of the following:

[0479] Identification information for multimedia sessions;

[0480] Information used to indicate the retention of multimedia sessions;

[0481] Information used to indicate the establishment of a joint session;

[0482] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0483] The aforementioned information transmission device can improve the terminal's call performance.

[0484] The communication device provided in this application embodiment can implement the various processes implemented in the method embodiment of FIG5 and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0485] Referring to Figure 16, when the information transmission device is a network-side device or a component within a network-side device, the information transmission device 1600 includes:

[0486] Receiver module 1601 is used to receive update requests;

[0487] The sending module 1602 is used to send information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network.

[0488] The aforementioned information transmission device can improve the terminal's call performance.

[0489] The communication device provided in this application embodiment can implement the various processes implemented in the method embodiment of FIG6 and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0490] Referring to Figure 17, when the information transmission device is a terminal or a component within a terminal, the information transmission device 1700 includes:

[0491] Receiving module 1701 is configured to acquire first information of a first mobile communication network, wherein the first information is used to indicate at least one of the following:

[0492] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0493] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0494] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0495] It supports or does not support falling back to the third mobile communication network.

[0496] The aforementioned information transmission device can improve the terminal's call performance.

[0497] The communication device provided in this application embodiment can implement the various processes implemented in the method embodiment of FIG7 and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0498] Referring to Figure 18, when the information transmission device is a terminal or a component within a terminal, the information transmission device 1800 includes:

[0499] The sending module 1801 is configured to send a multimedia session establishment request to a network-side device of a second or third mobile communication network, the establishment request including at least one of the following:

[0500] Identification information for multimedia sessions;

[0501] Information used to indicate the retention of multimedia sessions;

[0502] Information used to indicate the establishment of a joint session;

[0503] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0504] The aforementioned information transmission device can improve the terminal's call performance.

[0505] The communication device provided in this application embodiment can implement the various processes implemented in the method embodiment of FIG8 and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0506] As shown in Figure 19, this application embodiment also provides a communication device 1900, including a processor 1901 and a memory 1902. The memory 1902 stores programs or instructions that can run on the processor 1901. For example, when the communication device 1900 is a terminal, the program or instructions executed by the processor 1901 implement the various steps of the above-described call method or information transmission method embodiments and achieve the same technical effect. When the communication device 1900 is a network-side device, the program or instructions executed by the processor 1901 implement the various steps of the above-described network-side device information transmission method embodiments and achieve the same technical effect. To avoid repetition, further details are omitted here.

[0507] This application also provides a terminal, including a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the steps in the method embodiments shown in FIG2, FIG7, or FIG8. This terminal embodiment corresponds to the above-described terminal-side method embodiments, and all implementation processes and methods of the above-described method embodiments can be applied to this terminal embodiment and can achieve the same technical effect. The terminal can be the device shown in FIG12, FIG17, or FIG18. Specifically, FIG20 is a schematic diagram of the hardware structure of a terminal implementing an embodiment of this application.

[0508] The terminal 2000 includes, but is not limited to, at least some of the following components: radio frequency unit 2001, network module 2002, audio output unit 2003, input unit 2004, sensor 2005, display unit 2006, user input unit 2007, interface unit 2008, memory 2009, and processor 2010.

[0509] Those skilled in the art will understand that the terminal 2000 may also include a power supply (such as a battery) for powering various components. The power supply can be logically connected to the processor 2010 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The terminal structure shown in Figure 20 does not constitute a limitation on the terminal. The terminal may include more or fewer components than shown, or combine certain components, or have different component arrangements, which will not be elaborated here.

[0510] It should be understood that, in this embodiment, the input unit 2004 may include a graphics processor 20041 and a microphone 20042. The graphics processor 20041 processes image data of still images or videos obtained by an image capture device (such as a camera) in video capture mode or image capture mode. The display unit 2006 may include a display panel 20061, which may be configured in the form of a liquid crystal display, an organic light-emitting diode, or the like. The user input unit 2007 includes at least one of a touch panel 20071 and other input devices 20072. The touch panel 20071 is also called a touch screen. The touch panel 20071 may include a touch detection device and a touch controller. Other input devices 20072 may include, but are not limited to, physical keyboards, function keys (such as volume control buttons, power buttons, etc.), trackballs, mice, and joysticks, which will not be described in detail here.

[0511] In this embodiment, after receiving downlink data from the network-side device, the radio frequency unit 2001 can transmit it to the processor 2010 for processing; in addition, the radio frequency unit 2001 can send uplink data to the network-side device. Typically, the radio frequency unit 2001 includes, but is not limited to, antennas, amplifiers, transceivers, couplers, low-noise amplifiers, duplexers, etc.

[0512] The memory 2009 can be used to store software programs or instructions, as well as various data. The memory 2009 may primarily include a first storage area for storing programs or instructions and a second storage area for storing data. The first storage area may store the operating system, application programs or instructions required for at least one function (such as sound playback, image playback, etc.). Furthermore, the memory 2009 may include volatile memory or non-volatile memory. The non-volatile memory may 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. Volatile memory can be random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DRRAM). The memory 2009 in the embodiments of this application includes, but is not limited to, these and any other suitable types of memory.

[0513] Processor 2010 may include one or more processing units; optionally, processor 2010 integrates an application processor and a modem processor, wherein the application processor mainly handles operations involving the operating system, user interface, and applications, and the modem processor mainly handles wireless communication signals, such as a baseband processor. It is understood that the aforementioned modem processor may also not be integrated into processor 2010.

[0514] In one embodiment:

[0515] Radio frequency unit 2001 is configured to perform a call operation when the first mobile communication network is in a registered state, the call operation including at least one of the following:

[0516] Initiate the first call request through the second or third mobile communication network;

[0517] A call response is sent through a second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network.

[0518] Optionally, when the first mobile communication network is in a registered state, performing the call operation includes:

[0519] When the first mobile communication network is in a registered state and a multimedia session has been established on the first mobile communication network, a call operation is performed.

[0520] Optionally, the radio frequency unit 2001 is also used for:

[0521] Obtain first information from the first mobile communication network, wherein the first information is used to indicate at least one of the following:

[0522] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0523] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0524] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0525] It supports or does not support falling back to the third mobile communication network.

[0526] Optionally, obtaining the first information of the first mobile communication network includes:

[0527] Receive the registration acceptance message sent by the network-side device of the first mobile communication network;

[0528] Wherein, the registration acceptance message includes the first information, or,

[0529] The registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

[0530] Optionally, the call operation includes at least one of the following:

[0531] Under the first condition, a first call request is initiated through the second mobile communication network;

[0532] Under the second condition, a first call request is initiated through the third mobile communication network;

[0533] Under the first condition, a call response is sent through the second mobile communication network;

[0534] Under the second condition, a call response is sent through the third mobile communication network;

[0535] The first condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0536] The second condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0537] Optionally, the radio frequency unit 2001 is also used for at least one of the following:

[0538] The registration process is initiated through the second mobile communication network or the third mobile communication network;

[0539] Establish a multimedia session on the second mobile communication network or the third mobile communication network.

[0540] Optionally, the registration process initiated through the second mobile communication network or the third mobile communication network includes at least one of the following:

[0541] Under the third condition, the registration process is initiated through the second mobile communication network;

[0542] Under the fourth condition, the registration process is initiated through the third mobile communication network;

[0543] The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0544] The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0545] Optionally, establishing a multimedia session in the second mobile communication network or the third mobile communication network includes at least one of the following:

[0546] Under the third condition, a multimedia session is established on the second mobile communication network;

[0547] Under the fourth condition, a multimedia session is established on the third mobile communication network;

[0548] The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network.

[0549] The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

[0550] Optionally, the call operation includes one of the following:

[0551] The terminal initiates a call request through a multimedia session established in the second mobile communication network;

[0552] The terminal initiates a call request through a multimedia session established on the third mobile communication network;

[0553] The terminal sends a call response through a multimedia session established in the second mobile communication network;

[0554] The terminal sends a call response through a multimedia session established on the third mobile communication network.

[0555] Optionally, establishing a multimedia session in the second mobile communication network or the third mobile communication network includes:

[0556] Sending a multimedia session establishment request to a network-side device of the second mobile communication network or the third mobile communication network, the establishment request including at least one of the following:

[0557] Identification information for multimedia sessions;

[0558] Information used to indicate the retention of multimedia sessions;

[0559] Information used to indicate the establishment of a joint session;

[0560] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0561] Optionally, the radio frequency unit 2001 is also used for at least one of the following:

[0562] If the call ends, a request to release the multimedia session is initiated on the second mobile communication network or the third mobile communication network;

[0563] If the call ends, a deregistration process is initiated on the second mobile communication network or the third mobile communication network;

[0564] When the call ends, a modification process is initiated through the first mobile communication network. The modification process is used to modify the multimedia session established by the terminal on the first mobile communication network to an available state.

[0565] Optionally, the first mobile communication network includes a 6G mobile communication network, the second mobile communication network includes a 5G mobile communication network, and the third mobile communication network includes a 4G mobile communication network.

[0566] In another embodiment:

[0567] Radio frequency unit 2001 is configured to acquire first information of a first mobile communication network, wherein the first information is configured to indicate at least one of the following:

[0568] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0569] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0570] It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0571] It supports or does not support falling back to the third mobile communication network.

[0572] In another embodiment:

[0573] Radio frequency unit 2001 is used to send a multimedia session establishment request to a network-side device of a second mobile communication network or a third mobile communication network, the establishment request including at least one of the following:

[0574] Identification information for multimedia sessions;

[0575] Information used to indicate the retention of multimedia sessions;

[0576] Information used to indicate the establishment of a joint session;

[0577] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0578] The aforementioned terminals can improve the terminal's call performance.

[0579] It is understood that the implementation process of each implementation method mentioned in this embodiment can refer to the relevant descriptions of the method embodiments shown in Figures 2, 7 or 8, and achieve the same or corresponding technical effects. To avoid repetition, it will not be described again here.

[0580] This application also provides a network-side device, including a processor and a communication interface. The communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the steps of the method embodiments shown in Figures 3, 4, 5, or 6. This network-side device embodiment corresponds to the above-described network-side device method embodiments. All implementation processes and methods of the above-described method embodiments can be applied to this network-side device embodiment and achieve the same technical effects.

[0581] Specifically, this application also provides a network-side device. As shown in FIG21, the network-side device 2100 includes a processor 2101, a network interface 2102, and a memory 2103. The network-side device may be the device shown in FIG13, FIG14, FIG15, or FIG16. The network interface 2102 is, for example, a Common Public Radio Interface (CPRI).

[0582] Specifically, the network-side device 2100 in this application embodiment further includes: instructions or programs stored in memory 2103 and executable on processor 2101. The processor 2101 calls the instructions or programs in memory 2103 to execute the methods executed by the modules shown in FIG13, FIG14, FIG15 or FIG16 and achieve the same technical effect. To avoid repetition, it will not be described in detail here.

[0583] In one embodiment:

[0584] Network interface 2102 is used to send first information to the terminal, wherein the first network-side device is a network-side device of a first mobile communication network, and the first information is used to indicate at least one of the following:

[0585] It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network.

[0586] It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network.

[0587] It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network.

[0588] It supports or does not support falling back to the third mobile communication network.

[0589] Optionally, sending the first information to the terminal includes:

[0590] Send a registration acceptance message to the terminal, wherein the registration acceptance message includes the first information, or the registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

[0591] In one embodiment:

[0592] Network interface 2102 is used to receive requests to establish a multimedia session;

[0593] The establishment request includes at least one of the following:

[0594] Identification information for multimedia sessions;

[0595] Information used to indicate the retention of multimedia sessions;

[0596] Information used to indicate the establishment of a joint session;

[0597] The identification information of the multimedia session refers to the multimedia session established by the terminal in the first mobile communication network.

[0598] Optionally, processor 2101 is used for at least one of the following:

[0599] Assign address information for the multimedia session corresponding to the identification information to the terminal;

[0600] The multimedia session corresponding to the identification information is retained;

[0601] Set the multimedia session corresponding to the identification information to an unavailable state;

[0602] Establish a joint session.

[0603] In one embodiment:

[0604] Network interface 2102 is used to receive registration requests sent by the terminal;

[0605] An update request is sent to the fourth network-side device according to the registration request;

[0606] The terminal receives information from the fourth network-side device regarding the second network-side device corresponding to the establishment of a multimedia session in the first mobile communication network.

[0607] Optionally, network interface 2102 is also used for:

[0608] The terminal sends a multimedia session establishment request, the establishment request including at least one of the following:

[0609] Identification information for multimedia sessions;

[0610] Information used to indicate the retention of multimedia sessions;

[0611] Information used to indicate the establishment of a joint session;

[0612] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0613] Optionally, network interface 2102 is also used for:

[0614] Send an establishment request to the second network-side device, the establishment request including at least one of the following:

[0615] Identification information for multimedia sessions;

[0616] Information used to indicate the retention of multimedia sessions;

[0617] Information used to indicate the establishment of a joint session;

[0618] The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

[0619] In one embodiment:

[0620] Network interface 2102 is used to receive update requests and send information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network.

[0621] The aforementioned network-side equipment can improve the terminal's call performance.

[0622] It is understood that the implementation process of each implementation method mentioned in this embodiment can refer to the relevant descriptions of the method embodiments shown in Figures 3, 4, 5 or 6, and achieve the same or corresponding technical effects. To avoid repetition, it will not be described again here.

[0623] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described communication method or information transmission method embodiments and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0624] The processor mentioned above is the processor in the terminal described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk. In some examples, the readable storage medium may be a non-transient readable storage medium.

[0625] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described communication method or information transmission method embodiments and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0626] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0627] This application also provides a computer program / program product, which is stored in a storage medium and executed by at least one processor to implement the various processes of the above-described communication method or information transmission method embodiments, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0628] This application also provides a wireless communication system, including a terminal, and at least one of a first network-side device, a second network-side device, a third network-side device, and a fourth network-side device. The terminal can be used to perform the steps of the above-described call method, or to perform the steps of the terminal-side information transmission method. The first network-side device can be used to perform the steps of the information transmission method of the first network-side device, the second network-side device can be used to perform the steps of the information transmission method of the second network-side device, the third network-side device can be used to perform the steps of the information transmission method of the third network-side device, and the fourth network-side device can be used to perform the steps of the information transmission method of the fourth network-side device.

[0629] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0630] From the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of computer software products plus necessary general-purpose hardware platforms, and of course, they can also be implemented by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disk, optical disk, etc.) and includes several instructions to cause the terminal or network-side device to execute the methods described in the various embodiments of this application.

[0631] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other implementations under the guidance of this application without departing from the spirit and scope of the claims. All of these implementations are within the protection scope of this application.

Claims

1. A method for making a call, comprising: When the terminal is registered with the first mobile communication network, it performs a call operation, which includes at least one of the following: Initiate the first call request through the second or third mobile communication network; A call response is sent through a second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network.

2. The method according to claim 1, wherein, When the terminal is registered with the first mobile communication network, it performs a call operation, including: The terminal performs the call operation when it is registered in the first mobile communication network and a multimedia session has been established in the first mobile communication network.

3. The method according to claim 1 or 2, wherein, The method further includes: The terminal acquires first information from the first mobile communication network, wherein the first information is used to indicate at least one of the following: It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network. It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network. It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network. It supports or does not support falling back to the third mobile communication network.

4. The method according to claim 3, wherein, The terminal acquires first information from the first mobile communication network, including: The terminal receives a registration acceptance message sent by the network-side device of the first mobile communication network; Wherein, the registration acceptance message includes the first information, or, The registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

5. The method according to claim 3 or 4, wherein, The call operation includes at least one of the following: Under the first condition, a first call request is initiated through the second mobile communication network; Under the second condition, a first call request is initiated through the third mobile communication network; Under the first condition, a call response is sent through the second mobile communication network; Under the second condition, a call response is sent through the third mobile communication network; The first condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network. The second condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

6. The method according to any one of claims 1 to 5, wherein, The method further includes at least one of the following: The terminal initiates the registration process through the second mobile communication network or the third mobile communication network; The terminal establishes a multimedia session on the second mobile communication network or the third mobile communication network.

7. The method according to claim 6, wherein, The terminal initiates a registration process through the second mobile communication network or the third mobile communication network, including at least one of the following: Under the third condition, the terminal initiates the registration process through the second mobile communication network; Under the fourth condition, the terminal initiates the registration process through the third mobile communication network; The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network. The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

8. The method according to claim 6, wherein, The terminal establishes a multimedia session on the second mobile communication network or the third mobile communication network, including at least one of the following: Under the third condition, a multimedia session is established on the second mobile communication network; Under the fourth condition, a multimedia session is established on the third mobile communication network; The third condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, or it supports multimedia service transmission through the second mobile communication network. The fourth condition includes at least one of the following: it does not support multimedia service transmission through the first mobile communication network, it does not support multimedia service transmission through the second mobile communication network, it supports multimedia service transmission through the third mobile communication network, and it supports falling back to the third mobile communication network.

9. The method according to any one of claims 6 to 8, wherein, The call operation includes the following: The terminal initiates a call request through a multimedia session established in the second mobile communication network; The terminal initiates a call request through a multimedia session established on the third mobile communication network; The terminal sends a call response through a multimedia session established in the second mobile communication network; The terminal sends a call response through a multimedia session established on the third mobile communication network.

10. The method according to any one of claims 6 to 9, wherein, The terminal establishes a multimedia session on the second mobile communication network or the third mobile communication network, including: The terminal sends a multimedia session establishment request to the network-side device of the second mobile communication network or the third mobile communication network, the establishment request including at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

11. The method according to any one of claims 6 to 10, wherein, The method further includes at least one of the following: When a call ends, the terminal initiates a multimedia session release request on the second mobile communication network or the third mobile communication network. When a call ends, the terminal initiates a deregistration process on the second mobile communication network or the third mobile communication network. When a call ends, the terminal initiates a modification process through the first mobile communication network. The modification process is used to modify the multimedia session established by the terminal on the first mobile communication network to an available state.

12. The method according to any one of claims 1 to 11, wherein, The first mobile communication network includes a 6G mobile communication network, the second mobile communication network includes a 5G mobile communication network, and the third mobile communication network includes a 4G mobile communication network.

13. An information transmission method, comprising: A first network-side device sends first information to a terminal, wherein the first network-side device is a network-side device of a first mobile communication network, and the first information is used to indicate at least one of the following: It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network. It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network. It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network. It supports or does not support falling back to the third mobile communication network.

14. The method according to claim 13, wherein, The first network-side device sends first information to the terminal, including: The first network-side device sends a registration acceptance message to the terminal, wherein the registration acceptance message includes the first information, or the registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

15. An information transmission method, comprising: The second network-side device receives the request to establish a multimedia session; The establishment request includes at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session refers to the multimedia session established by the terminal in the first mobile communication network.

16. The method according to claim 15, wherein, The method further includes at least one of the following: The second network-side device assigns the address information of the multimedia session corresponding to the identification information to the terminal; The second network-side device retains the multimedia session corresponding to the identification information; The second network-side device sets the multimedia session corresponding to the identification information to an unavailable state; The second network-side device establishes a joint session.

17. An information transmission method, comprising: The third network-side device receives the registration request sent by the terminal; The third network-side device sends an update request to the fourth network-side device according to the registration request; The third network-side device receives information from the fourth network-side device regarding the second network-side device corresponding to the establishment of a multimedia session by the terminal in the first mobile communication network.

18. The method according to claim 17, wherein, The method further includes: The third network-side device receives a multimedia session establishment request sent by the terminal, the establishment request including at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

19. The method according to claim 17 or 18, wherein, The method further includes: The third network-side device sends an establishment request to the second network-side device, the establishment request including at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

20. An information transmission method, comprising: The fourth network-side device receives the update request; The fourth network-side device sends information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network.

21. An information transmission method, comprising: The terminal acquires first information from a first mobile communication network, wherein the first information is used to indicate at least one of the following: It supports multimedia service transmission via the first mobile communication network or does not support multimedia service transmission via the first mobile communication network. It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network. It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network. It supports or does not support falling back to the third mobile communication network.

22. An information transmission method, comprising: The terminal sends a multimedia session establishment request to a network-side device in a second or third mobile communication network, the establishment request including at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

23. A communication device, comprising: The processing module is configured to perform a call operation when the first mobile communication network is in a registered state, the call operation including at least one of the following: Initiate the first call request through the second or third mobile communication network; A call response is sent through a second or third mobile communication network, wherein the call response is a response to a second call request, which is a call request received by the terminal through the first mobile communication network.

24. The apparatus according to claim 23, wherein, The device further includes: The receiving module is configured to acquire first information from the first mobile communication network, wherein the first information is used to indicate at least one of the following: It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network. It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network. It supports multimedia service transmission via the third mobile communication network or does not support multimedia service transmission via the third mobile communication network. It supports or does not support falling back to the third mobile communication network.

25. The apparatus according to claim 23 or 24, wherein, The device further includes: The sending module is used to initiate a registration process through the second mobile communication network or the third mobile communication network; And / or, The processing module is also used to establish a multimedia session on the second mobile communication network or the third mobile communication network.

26. The apparatus according to any one of claims 23 to 25, wherein, The transmitting module included in the device is further used for at least one of the following: If the call ends, a request to release the multimedia session is initiated on the second mobile communication network or the third mobile communication network; If the call ends, a deregistration process is initiated on the second mobile communication network or the third mobile communication network; When the call ends, a modification process is initiated through the first mobile communication network. The modification process is used to modify the multimedia session established by the terminal on the first mobile communication network to an available state.

27. An information transmission device, comprising: The sending module is used to send first information to the terminal. The network-side device corresponding to the device is a network-side device of a first mobile communication network. The first information is used to indicate at least one of the following: It supports multimedia service transmission through the first mobile communication network or does not support multimedia service transmission through the first mobile communication network. It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network. It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network. It supports or does not support falling back to the third mobile communication network.

28. The apparatus according to claim 27, wherein, Sending the first information to the terminal includes: Send a registration acceptance message to the terminal, wherein the registration acceptance message includes the first information, or the registration acceptance message includes the first information and indication information for indicating that the first mobile communication network supports dual protocol stack (DS).

29. An information transmission device, comprising: The receiving module is used to receive requests to establish multimedia sessions; The establishment request includes at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session refers to the multimedia session established by the terminal in the first mobile communication network.

30. The apparatus according to claim 29, wherein, The device further includes a processing module, the processing module being used for at least one of the following: Assign address information for the multimedia session corresponding to the identification information to the terminal; The multimedia session corresponding to the identification information is retained; Set the multimedia session corresponding to the identification information to an unavailable state; Establish a joint session.

31. An information transmission device, comprising: The receiving module is used to receive registration requests sent by the terminal; The sending module is used to send an update request to the fourth network-side device according to the registration request; The receiving module is also used to receive information from the fourth network-side device regarding the second network-side device corresponding to the establishment of a multimedia session by the terminal in the first mobile communication network.

32. The apparatus according to claim 31, wherein, The receiving module is further configured to receive a multimedia session establishment request sent by the terminal, the establishment request including at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

33. The apparatus according to claim 31 or 32, wherein, The sending module is further configured to send a creation request to the second network-side device, the creation request including at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

34. An information transmission device, comprising: The receiving module is used to receive update requests; The sending module is used to send information about the second network-side device corresponding to the multimedia session established by the terminal in the first mobile communication network.

35. An information transmission device, comprising: A receiving module is configured to acquire first information from a first mobile communication network, wherein the first information is used to indicate at least one of the following: It supports multimedia service transmission via the first mobile communication network or does not support multimedia service transmission via the first mobile communication network. It supports multimedia service transmission via the second mobile communication network or does not support multimedia service transmission via the second mobile communication network. It supports multimedia service transmission via a third mobile communication network or does not support multimedia service transmission via the third mobile communication network. It supports or does not support falling back to the third mobile communication network.

36. An information transmission device, comprising: The sending module is configured to send a multimedia session establishment request to a network-side device in a second or third mobile communication network, wherein the establishment request includes at least one of the following: Identification information for multimedia sessions; Information used to indicate the retention of multimedia sessions; Information used to indicate the establishment of a joint session; The identification information of the multimedia session is the identifier of the multimedia session established by the terminal in the first mobile communication network.

37. A communication device comprising a processor and a memory, the memory storing a program or instructions executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of a call method as claimed in any one of claims 1 to 12, or the program or instructions, when executed by the processor, implement the steps of an information transmission method as claimed in any one of claims 13 to 14, or the program or instructions, when executed by the processor, implement the steps of an information transmission method as claimed in any one of claims 15 to 16, or the program or instructions, when executed by the processor, implement the steps of an information transmission method as claimed in any one of claims 17 to 19, or the program or instructions, when executed by the processor, implement the steps of an information transmission method as claimed in claim 20, or the program or instructions, when executed by the processor, implement the steps of an information transmission method as claimed in claim 21, or the program or instructions, when executed by the processor, implement the steps of an information transmission method as claimed in claim 22.

38. A readable storage medium, wherein, The readable storage medium stores a program or instructions that, when executed by a processor, implement the steps of the call method as claimed in any one of claims 1 to 12, or the steps of the information transmission method as claimed in any one of claims 13 to 14, or the steps of the information transmission method as claimed in any one of claims 15 to 16, or the steps of the information transmission method as claimed in any one of claims 17 to 19, or the steps of the information transmission method as claimed in claim 20, or the steps of the information transmission method as claimed in claim 21, or the steps of the information transmission method as claimed in claim 22.

39. A computer program product, wherein, The computer program product is stored in a storage medium, and the computer program product is executed by at least one processor to implement the steps of the call method as claimed in any one of claims 1 to 12, or the steps of the information transmission method as claimed in any one of claims 13 to 14, or the steps of the information transmission method as claimed in any one of claims 15 to 16, or the steps of the information transmission method as claimed in any one of claims 17 to 19, or the steps of the information transmission method as claimed in claim 20, or the steps of the information transmission method as claimed in claim 21, or the steps of the information transmission method as claimed in claim 22.

40. A chip, wherein the chip includes a processor and a communication interface, the communication interface being coupled to the processor, the processor being configured to run a program or instructions to implement a call method as claimed in any one of claims 1 to 12, or an information transmission method as claimed in any one of claims 13 to 14, or an information transmission method as claimed in any one of claims 15 to 16, or an information transmission method as claimed in any one of claims 17 to 19, or an information transmission method as claimed in claim 20, or an information transmission method as claimed in claim 21, or an information transmission method as claimed in claim 22.

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