Method and device for call connection

Abstract

The invention provides a method and a device for call connection, which are applied to a process of establishing a call between a calling side and a called side in a scene that a called terminal subscribes to a polyphonic ringtone service. The method comprises the following steps: in a signaling interaction process of a calling terminal and a called terminal, after a user of the called terminal clicks an answering action, if the called terminal does not receive a first ACK signaling replied by a network side (such as S-CSCF) all the time, but receives a second INVITE signaling; under the condition, the called terminal defaults that the network side has sent the first ACK signaling, and replies a second 200OK (INVITE) signaling to the network side after receiving the second INVITE signaling. Compared with a mode of replying the 491 signaling under the condition, the method provided by the embodiment of the invention has the advantages that the silent conversation probability is reduced, the conversation success probability can be improved, and the conversation experience of the user can be improved.

Description

Technical Field

[0001] The present application relates to the field of calls, and in particular, to a method and device for call connection. Background Art

[0002] Currently, most terminals support the color ring back tone function. Operators usually enable the color ring back tone function for terminal users by default. Taking the called terminal as an example, after the called terminal activates the color ring back tone service, when the calling terminal dials the called terminal, during the ringing period of the called terminal, the color ring back tone platform in the telecommunications network plays an audio ring tone to the calling terminal as a waiting tone (ringback tone).

[0003] In the process of establishing a call connection, the calling terminal and the called terminal can communicate using messages or signaling in the Session Initiation Protocol (SIP). SIP is an application layer control protocol proposed by the Internet Engineering Task Force (IETF) for multimedia communications over IP networks.

[0004] The signaling interaction process involved in the call establishment process is different between terminals with and without the color ring back tone function. After the color ring back tone function is activated, the establishment of a call connection between the called terminal and the calling terminal will increase many signaling processes, and some signaling may be lost during the signaling forwarding process, which will cause the call between the calling terminal and the called terminal to be unable to be established. Therefore, compared with terminals without the color ring back tone function, terminals with the color ring back tone function activated are more likely to have problems such as silence or single-call after the call, affecting the user's call experience. Summary of the invention

[0005] In view of this, the present application provides a method, device, computer-readable storage medium and computer program product for call connection, which can reduce the probability of silent calls and improve the user's call experience.

[0006] In a first aspect, a method for call connection is provided, the method being applied to a first terminal, the method comprising:

[0007] When the second terminal initiates a first call to the first terminal, receiving a first INVITE signaling from the second terminal;

[0008] After detecting the user's answering action, sending a first 200OK signaling in response to the first INVITE signaling;

[0009] Based on the first call, receiving a second INVITE signaling, the second INVITE signaling includes a first identifier, the first INVITE signaling does not include the first identifier, and the first terminal does not receive a first ACK signaling after sending the first 200OK signaling and before receiving the second INVITE signaling;

[0010] In response to the second INVITE signaling, a second 200OK signaling is sent.

[0011] The above technical solution is executed by the first terminal or the chip in the first terminal. Based on the above solution, after receiving the user answering action of the first terminal, for the situation where the first terminal did not receive the first ACK signaling replied by the network side but received the second INVITE signaling, compared with the way in which the first terminal replies to the network side with 491 signaling (this way makes the subsequent signaling interaction steps unable to be executed, resulting in silent calls between the first terminal and the second terminal), the embodiment of the present application will default to having received the first ACK signaling in this case, and reply to the network side with the second 200OK (INVITE) signaling after receiving the second INVITE signaling, so that the subsequent signaling interaction steps can be executed normally, so that voice data can be transmitted between the first terminal and the second terminal, which helps to increase the probability of successful calls and enhance the user's call experience.

[0012] Exemplarily, the first terminal is a called terminal, and the second terminal is a calling terminal.

[0013] In some possible implementations, after receiving the second INVITE signaling, the method further includes:

[0014] Determining whether the first ACK signaling is received;

[0015] When the first ACK signaling is not received, the second 200OK signaling is sent.

[0016] That is, after receiving the second INVITE signaling, the first terminal can determine whether the first ACK signaling has been received. Even if the first ACK signaling has not been received, the second 200OK signaling will be sent to the network side.

[0017] Optionally, a preset time length may be set on the first terminal side to constrain the time the first terminal waits for the second INVITE signaling, so as to avoid the first terminal waiting for the second INVITE signaling all the time.

[0018] Optionally, the above-mentioned preset duration can be achieved by introducing a first timer.

[0019] In some possible implementations, the method further includes:

[0020] Determining whether the first timer has timed out;

[0021] The sending of the second 200OK signaling includes:

[0022] If the first ACK signaling is not received and the first timer has not timed out, the second 200OK signaling is sent. The first timer has not timed out, which means that the timing duration of the first timer is less than or equal to the preset duration. The timing duration of the first timer refers to the time between the moment when the user's answering action is detected and the current moment, or the time between the moment when the first 200OK signaling is sent and the current moment.

[0023] Optionally, after the first terminal receives the user's answering action or sends the first 200 OK (INVITE) signaling, the first timer starts timing (or starts the first timer).

[0024] In some possible implementations, the method further includes: sending a 491 signaling when the first ACK signaling is not received and the first timer times out. That is, if the second INVITE signaling is sent when the first timer times out, the first terminal replies with a 491 signaling.

[0025] In some possible implementations, the method further includes:

[0026] receiving a second ACK signaling from the second terminal;

[0027] After receiving the second ACK signaling, receive voice data from the second terminal, or send voice data to the second terminal.

[0028] After the first terminal responds to the network with the second 200 OK (INVITE) signaling, the subsequent steps can be performed normally. For example, the first terminal can receive the second ACK signaling from the second terminal, and then transmit voice data with the second terminal.

[0029] It should be understood that the signaling shown above is part of the signaling between the first terminal and the second terminal, and the embodiments of the present application are not limited to this.

[0030] In some possible implementations, the method further includes:

[0031] After receiving the first INVITE signaling, a 180 Ringing signaling is sent to the second terminal.

[0032] In some possible implementations, before sending the 180Ringing signaling, the method further includes:

[0033] receiving an UPDATE signaling from the second terminal;

[0034] In response to the UPDATE signaling, a third 200OK signaling is sent. The third 200OK signaling is a 200OK (UPDATE) signaling.

[0035] Exemplarily, 200 OK (UPDATE) signaling may indicate that UPDATE signaling has been received.

[0036] Therefore, the first terminal can learn, through the UPDATE signaling, that the second terminal has established a voice bearer, and reply with a 200 OK (UPDATE) signaling to the second terminal.

[0037] In some possible implementations, the first 200OK signaling is sent after the playing of the color ring tone starts; and the second INVITE signaling is received after the playing of the color ring tone stops.

[0038] In a second aspect, a method for call connection is provided, the method being applied to a first network side device. The first network side device may be a first core network device (eg, a first S-CSCF) or a first access network device. The method comprises:

[0039] Sending a first INVITE signaling from the second terminal to the first terminal;

[0040] receiving a first 200OK signaling from the first terminal, where the first 200OK signaling is sent by the first terminal in response to the first INVITE signaling after detecting a user's answering action;

[0041] In a case where the first ACK signaling is not sent to the first terminal, a second INVITE signaling is sent to the first terminal, where the second INVITE signaling includes the first identifier, and the first INVITE signaling does not include the first identifier;

[0042] A second 200OK signaling is received from the first terminal, where the second 200OK signaling is sent by the first terminal in response to the second INVITE signaling.

[0043] The above technical solution is executed by the first network side device or the chip in the first network side device. Based on the above solution, the first network side device sends a second INVITE signaling to the first terminal without sending the first ACK signaling to the first terminal or fails to send the first ACK signaling, and receives the second 200OK signaling from the first terminal, so that the subsequent signaling interaction steps can be executed normally, so that the voice data between the first terminal and the second terminal can be forwarded, which helps to increase the probability of call success and improve the user's call experience.

[0044] In a third aspect, a method for call connection is provided, the method being applied to a color ring back tone server. The method comprises:

[0045] Receiving a first INVITE signaling from a second terminal;

[0046] Reserving color ringback tone resources, and sending the first INVITE signaling to the first terminal;

[0047] After receiving the 180Ringing signaling from the first terminal, sending the 180Ringing signaling carrying the color ring back tone indication to the second terminal;

[0048] After receiving the PRACK signaling from the second terminal, start playing the ring back tone;

[0049] receiving a first 200OK signaling from the first terminal, the first 200OK signaling responding to the first INVITE signaling;

[0050] Stop playing the ringback tone and send the first ACK signaling (which may not be sent successfully);

[0051] Send the second INVITE signaling;

[0052] A second 200OK signaling is received from the first terminal, where the second 200OK signaling responds to the second INVITE signaling.

[0053] The above technical solution is executed by the color ring back tone server or the chip in the color ring back tone server. Based on the above solution, when the color ring back tone server fails to send the first ACK signaling or fails to send the first ACK signaling, it sends the second INVITE signaling and receives the second 200OK signaling from the first terminal, so that the subsequent signaling interaction steps can be executed normally, so that the voice data between the first terminal and the second terminal can be forwarded, which helps to increase the probability of call success and improve the user's call experience.

[0054] In a fourth aspect, a method for call connection is provided, the method being applied to a second terminal. The method comprises:

[0055] When initiating a first call to the first terminal, sending a first INVITE signaling to the first terminal;

[0056] receiving a first 200OK signaling from the first terminal, where the first 200OK signaling responds to the first INVITE signaling;

[0057] A second ACK signaling is sent to the first terminal.

[0058] The above technical solution is executed by the second terminal or the chip in the second terminal. Based on the above solution, when initiating a call, the second terminal sends a first INVITE signaling to the first terminal, and after receiving a first 200OK signaling from the first terminal, replies to the first terminal with a second ACK signaling, so that subsequent signaling interaction steps can be performed normally, thereby being able to transmit voice data between the first terminal and the second terminal, which helps to increase the probability of a successful call and enhance the user's call experience.

[0059] It can be understood that the signaling involved above is part of the signaling between the first terminal and the second terminal, and the embodiments of the present application are not limited to this.

[0060] Optionally, after sending the second ACK signaling to the first terminal, the method further includes:

[0061] Send voice data to the first terminal, or receive voice data from the first terminal.

[0062] Optionally, the method further comprises:

[0063] Sending UPDATE signaling to the first terminal;

[0064] receiving a 200OK (UPDATE) signaling from the first terminal;

[0065] A 180Ringing signaling is received from the first terminal, where the 180Ringing signaling includes a color ring back tone indication.

[0066] Optionally, when the color ring back tone server starts playing the color ring back tone, the second terminal starts playing the color ring back tone, and the user of the second terminal can hear the played color ring back tone;

[0067] When the color ring back tone server stops playing the color ring back tone, the second terminal stops playing the color ring back tone, and the user of the second terminal cannot hear the played color ring back tone at this time.

[0068] In a fifth aspect, an electronic device is provided, comprising a unit for executing the method in any one of the implementations in the first aspect. The electronic device may be a first terminal or a chip in the first terminal. The electronic device comprises an input unit, a display unit, and a processing unit.

[0069] When the electronic device is a first terminal, the processing unit may be a processor, the input unit may be a communication interface, and the display unit may be a graphics processing module and a screen; the terminal may also include a memory for storing computer program code, and when the processor executes the computer program code stored in the memory, the terminal executes the method in any one of the implementation modes of the first aspect.

[0070] When the electronic device is a chip in the first terminal, the processing unit may be a logic processing unit inside the chip, the input unit may be an input interface, a pin or a circuit, etc., and the display unit may be a graphics processing unit inside the chip; the chip may also include a memory, which may be a memory inside the chip (for example, a register, a cache, etc.) or a memory located outside the chip (for example, a read-only memory, a random access memory, etc.); the memory is used to store computer program code, and when the processor executes the computer program code stored in the memory, the chip executes any one of the methods of the first aspect.

[0071] In a sixth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program code, and when the computer program code is executed by a device for call connection, the transposition executes the method in any one of the implementation modes in the first aspect.

[0072] In a seventh aspect, a computer program product is provided, the computer program product comprising: a computer program code, when the computer program code is executed in a device for call connection, the device executes any one of the methods in the first aspect.

[0073] In an eighth aspect, an embodiment of the present application provides a chip system, which includes one or more processors for calling and executing instructions stored in a memory from a memory, so that the method in any possible implementation of each of the above aspects or each aspect is executed. The chip system can be composed of a chip, or it can include a chip and other discrete devices.

[0074] Among them, the chip system may include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0075] In a ninth aspect, a communication system is provided, comprising one or more of the aforementioned first terminal, the second terminal, the color ring back tone server (such as CAT-AS), the first core network device (such as the first S-CSCF), and the second core network device (such as the second S-CSCF). Optionally, the communication system may also include other devices that communicate with the aforementioned devices (such as the calling access network device and the called access network device). BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 is a scene example diagram of a communication system to which an embodiment of the present application is applied;

[0077] Figure 2 This is an example diagram of signaling interaction of a voice call when the first terminal activates the color ring back tone service;

[0078] Figure 3 is a signaling interaction flow chart when the first terminal does not receive the first ACK signaling;

[0079] Figure 4 is an example diagram of signaling interaction when the first terminal does not receive the first ACK signaling in an embodiment of the present application;

[0080] Figure 5 is an example diagram of the method flow executed by the first terminal in an embodiment of the present application;

[0081] Figure 6 is an example block diagram of a device for call connection according to an embodiment of the present application;

[0082] Figure 7 is a structural diagram of a device for call connection according to an embodiment of the present application;

[0083] Figure 8 is a structural example diagram of an electronic device according to an embodiment of the present application;

[0084] Fig. 9 It is a schematic block diagram of the software structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0085] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0086] In the embodiments of the present application, unless otherwise specified, “plurality” may mean two or more than two.

[0087] The technical solution of the embodiment of the present application can be applied to various communication systems, such as: long term evolution (LTE) system, universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or new radio (NR) and future mobile communication system, vehicle-to-X V2X, where V2X may include vehicle to network (V2N), vehicle to vehicle (V2V), vehicle to infrastructure (V2I), vehicle to pedestrian (V2P), etc., long term evolution technology of vehicle communication (LTE-V), Internet of Vehicles, machine type communication (MTC), Internet of Things (IoT), long term evolution technology of machine communication (LTE-M), machine to machine (machine machine, M2M) etc.

[0088] Figure 1 1 is a diagram showing an example of a communication system using an embodiment of the present application. Figure 1 As shown, the communication system includes a second terminal, a first terminal, a first network side device, a second network side device, and a ring back tone server. A call connection can be established between the second terminal and the first terminal via a wireless access network.

[0089] The CRBT server is used to provide resources or information related to the CRBT service. The terminal can customize the CRBT service through the CRBT server so that the customized CRBT can be played when the terminal is called, so that the user on the calling side can listen to the CRBT while waiting for the call to be connected. For example, the CRBT server may include a customized alerting tones (CAT) application server (AS).

[0090] Optionally, the first terminal can customize the ring back tone service. For example, if the user of the first terminal customizes the ring back tone service, when the second terminal calls the first terminal, while waiting for the call to be connected, the ring back tone server can search the database for the ring back tone customized for the number corresponding to the first terminal for playing.

[0091] Exemplarily, the first terminal is a called terminal, and the second terminal is a calling terminal.

[0092] It should be understood that Figure 1 This is just a schematic diagram of the architecture of the communication system. The communication system may also include other network devices, such as wireless relay devices and wireless backhaul devices. Figure 1 The embodiments of the present application do not limit the number of core network devices, wireless access network devices and terminals included in the mobile communication system.

[0093] Optionally, Figure 1 The network side device shown in (whether the first network side device or the second network side device) may include a core network device and a wireless access network device.

[0094] Whether it is the calling side or the called side, the terminal is connected to the access network device in a wireless way, and the wireless access network device is connected to the core network device in a wireless or wired way. The core network device and the wireless access network device can be independent and different physical devices, or the functions of the core network device and the logical functions of the wireless access network device can be integrated on the same physical device, or the functions of some core network devices and some wireless access network devices can be integrated on one physical device. The terminal device can be fixed or movable.

[0095] Understandably, Figure 1 The first network side device and the second network side device shown in the figure are only exemplary descriptions, and the embodiments of the present application are not limited thereto. For example, the first network side device includes a first core network device and a first access network device) and the second network device includes a second core network device and a second access network device.

[0096] The terminal in the embodiment of the present application may also be referred to as: terminal equipment, user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent or user device, etc.

[0097] A terminal may be a device that provides voice / data connectivity to a user, such as a handheld device or a vehicle-mounted device with a wireless connection function. At present, some examples of terminals are: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MID), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals equipped with cloud games, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication functions, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in 5G networks or future evolved public land mobile communication networks (public land mobile communication networks) Mobile network, PLMN) and the like, but the embodiments of the present application are not limited to this.

[0098] As an example but not limitation, in the embodiments of the present application, the terminal may also be a wearable device. Wearable devices may also be referred to as wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also powerful functions achieved through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include full-featured, large-sized, and fully or partially independent of smartphones, such as smart watches or smart glasses, as well as devices that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various types of smart bracelets and smart jewelry for vital sign monitoring.

[0099] In addition, in the embodiments of the present application, the terminal may also be a terminal device in the Internet of Things (IoT) system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal.

[0100] The network referred to in the embodiments of the present application is a general term for the core network and access network equipment responsible for processing voice services, including Internet Protocol (IP) multimedia subsystem (IMS) network and other networks. The IMS network includes the IMS domain core network and the Evolved Packet Core (EPC). The IMS domain core network includes: serving-call session control function (S-CSCF), interrogating-call session control function (I-CSCF), proxy-call session control function (P-CSCF) session border controller (SBC), and several dedicated servers, such as multimedia telephony application server (MMTel AS). Among them, I-CSCF can be combined with S-CSCF, which can be referred to as "I / S-CSCF". SBC and P-CSCF can be combined, which can be referred to as "SBC / P-CSCF". The EPC may include a packet data network gateway (PGW), a serving gateway (SGW) and a mobile management entity (MME). The PGW and SGW may be combined and referred to as "SGW / PGW".

[0101] The above network elements are all corresponding network elements in the IMS network in the prior art. They will not be described in detail here, but only briefly explained. For example: S-CSCF can be used for user registration, authentication control, session routing and service triggering control, and maintain session status information. I-CSCF can be used for the assignment and query of S-CSCF registered by the user. P-CSCF can be used for signaling and message proxy. SBC can provide secure access and media processing. MMTel AS provides basic multimedia telephone services and supplementary services. MME is the core equipment of the EPC network. SGW can be used for the connection between the IMS core network and the wireless network, and PGW can be used for the connection between the IMS core network and the IP network.

[0102] The radio access network (RAN) device is an access device that the terminal accesses to the mobile communication system by wireless means, which may be a base station NodeB, an evolved base station (eNB), a next generation NodeB (gNB) in a 5G mobile communication system, a transmission point, a base station in a future mobile communication system or an access node in a Wi-Fi system, one or more antenna panels of a base station in a 5G system, or a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU). The embodiments of the present application do not limit the specific technology and specific device form adopted by the radio access network device. In some deployments, the gNB may include a centralized unit (CU) and a DU, and the CU and the DU respectively implement part of the functions of the gNB. For example, the CU is responsible for processing non-real-time protocols and services, and implementing the functions of the radio resource control (RRC) and the packet data convergence protocol (PDCP) layer. DU is responsible for processing physical layer protocols and real-time services, and implementing the functions of the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer. The gNB may also include an active antenna unit (AAU). The AAU implements some physical layer processing functions, radio frequency processing, and related functions of the active antenna. Since the information of the RRC layer will eventually become the information of the PHY layer, or be converted from the information of the PHY layer, therefore, under this architecture, high-level signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or, sent by the DU+AAU. It can be understood that the network device can be a device including one or more of the CU node, DU node, and AAU node. In addition, the CU can be used as a network device in the access network or as a network device in the core network (CN), and this application does not limit this.

[0103] The wireless access network equipment and terminals can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on the water surface; they can also be deployed on aircraft, balloons and satellites in the air. The embodiments of the present application do not limit the application scenarios of the wireless access network equipment and terminals.

[0104] The wireless access network device and the terminal, and the terminals can communicate through the licensed spectrum, and can also communicate through the unlicensed spectrum, or can also communicate through the licensed spectrum and the unlicensed spectrum at the same time. The wireless access network device and the terminal, and the terminals can communicate through the spectrum below 6 gigahertz (GHz), and can also communicate through the spectrum above 6G, and can also communicate using the spectrum below 6G and the spectrum above 6G at the same time. The embodiments of the present application do not limit the spectrum resources used between the wireless access network device and the terminal.

[0105] In an embodiment of the present application, a terminal or network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a central processing unit (CPU), a memory management unit (MMU), and a memory (also called main memory). The operating system can be any one or more computer operating systems that implement business processing through a process, such as a Linux operating system, a Unix operating system, an Android operating system, an iOS operating system, or a windows operating system. The application layer includes applications such as a browser, an address book, a word processing software, and an instant messaging software. In addition, the embodiment of the present application does not specifically limit the specific structure of the execution subject of the method provided in the embodiment of the present application, as long as it can communicate according to the method provided in the embodiment of the present application by running a program that records the code of the method provided in the embodiment of the present application, for example, the execution subject of the method provided in the embodiment of the present application can be a terminal device or a network device, or a functional module in a terminal device or a network device that can call a program and execute the program.

[0106] In addition, various aspects or features of the present application can be implemented as methods, devices or products using standard programming and / or engineering techniques. The term "product" used in this application covers computer programs that can be accessed from any computer-readable device, carrier or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks or tapes, etc.), optical disks (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards and flash memory devices (e.g., erasable programmable read-only memory (EPROM), cards, sticks or key drives, etc.). In addition, the various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and / or carrying instructions and / or data.

[0107] It should be noted that the explanation of signaling and terminology in this application can also refer to the explanation in the third generation partnership project (3GPP) standard protocol, such as 24.229, RFC3261 and RFC3262. The uppercase and lowercase letters and spaces of signaling in this application are only examples.

[0108] For example, the interaction process of the embodiment of the present application can be applied to the Session Initiation Protocol (SIP), which is a signaling protocol used to control the initiation, modification, and termination of interactive multimedia sessions.

[0109] The following is a brief introduction to some messages in the SIP protocol.

[0110] The session invitation message (INVITE) is used to initiate a session request. For example, the session invitation message may be initiated by the calling terminal.

[0111] Update message (UPDATE) is used to initiate an update request or update session parameters. Update message is usually used for media update. For example, the update message can be initiated by the calling terminal.

[0112] The provisional response message is a provisional response acknowledgement (PRACK), which is used to return an acknowledgement to a provisional reliability response, confirming that a 1XX provisional response has been received. For example, a PRACK message is usually used to confirm a 183 message when a session is established, and to provide a second session description protocol (SDP) to negotiate media resources.

[0113] ACK message indicates that the final response to the INVITE request has been received. After the caller receives the 200OK final response from the called party in the session, it sends an ACK message to the called party to confirm that the caller has received the final response, thus completing the three-way handshake consisting of INVITE, 200OK and ACK. The ACK message is only used in conjunction with the INVITE message.

[0114] BYE request is used to end the current session. When a BYE request is received, the current dialog session will be terminated. BYE request can only be sent in an established dialog (established by INVITE request). The caller of the session can send BYE request to terminate the session in the Early Dialog and the Confirmed Dialog, and the called party can only send BYE request to terminate the session in the Confirmed Dialog.

[0115] The SIP protocol response message is used to respond to the request message, indicating the success or failure status of the call. Different types of response messages are distinguished by status codes. Status codes usually contain three integers. The first bit of the status code is used to define the response type, and the other two bits are used to further describe the response in more detail.

[0116] SIP protocol response messages are classified as follows:

[0117] 1xx: Information response (call progress response), indicating that the request message has been received and is being processed.

[0118] For example, the 100Trying message is a temporary response message, indicating that the INVITE message has been received and is being processed. For another example, the 180Ringing message is a ringing message, indicating that the INVITE message has reached the called party and the called party has started ringing.

[0119] 2xx: Successful response, indicating that the request has been successfully accepted or processed. For example, the 200OK (INVITE) message is used to indicate that the INVITE request has been successfully accepted or processed.

[0120] 3xx: A redirection response, indicating that further action is required to complete the request.

[0121] 4xx: Client error, indicating that the request message contains a syntax error or the SIP server cannot complete the processing of the request message. For example, 491 (Request Pending) message.

[0122] It should be understood that the above-mentioned messages in the SIP protocol are merely exemplary descriptions, and the embodiments of the present application are not limited thereto.

[0123] refer to Figure 2 As shown, Figure 2 This is an example diagram of signaling interaction for a voice call when the first terminal activates the color ring back tone service. It should be understood that Figure 2 The various messages involved in the steps shown in the figure may be existing messages in the SIP protocol or newly defined messages, and no specific limitation is made to this. It should also be understood that Figure 2 The process shown can be applied to Figure 1 The scenario shown. For example, Figure 2 The S-CSCF shown in FIG. Figure 1 An example of a core network device in; Figure 2 The CAT-AS shown in the figure can be Figure 1 An example of a ring back tone server in ; Figure 2 The second terminal in can be Figure 1 The second terminal in; Figure 2 The first terminal in can be Figure 1 The first terminal in.

[0124] Optionally, in some embodiments, during a call between the second terminal and the first terminal, the user of the second terminal can hear the ringtone of the first terminal; after the user of the first terminal clicks to answer, the ringtone stops playing; a session is established normally between the first terminal and the second terminal, and the user of the second terminal can hear the sound of the first terminal.

[0125] Step 201: The second terminal sends a first INVITE signaling to the first terminal.

[0126] It should be noted that, combined with Figure 1 In the scenario shown, when a user of the second terminal dials the SIM card number of a user of the first terminal, the second terminal initiates a first call to the first terminal.

[0127] Exemplarily, the SIM card installed in the first terminal includes a first SIM card, and the SIM card installed in the second terminal includes a second SIM card. When a user of the second terminal dials the number of the first SIM card of the first terminal based on the second SIM card, the second terminal initiates a first call to the first terminal.

[0128] Exemplarily, when the user of the second terminal dials the number of the user of the first terminal, the second terminal sends a first INVITE signaling to the first terminal.

[0129] Alternatively, if Figure 2 As shown in, step 201 includes: the second terminal sends a first INVITE signaling to the second S-CSCF; after receiving the first INVITE signaling, the second S-CSCF sends the first INVITE signaling received from the second terminal to the CAT-AS; after receiving the first INVITE signaling, the CAT-AS can reserve color ringback tone resources (CAT resource) and send the received first INVITE signaling to the first S-CSCF; the first S-CSCF sends the first INVITE signaling to the first terminal.

[0130] Reserving ringback tone resources can be understood as preparation for the subsequent playing of the ringback tone, for example, reserving memory space for creating an instance.

[0131] It is understandable that the signaling interaction between the terminal and the S-CSCF needs to go through the access device. For simplicity, Figure 2 The access network device is not shown, but this does not constitute a limitation to the embodiments of the present application.

[0132] For example, in Figure 2 In step 201, when the second terminal sends the first INVITE signaling to the second S-CSCF, it needs to be forwarded through the second access network device, specifically: the second terminal sends the first INVITE signaling to the second access network device; the second access network device sends the first INVITE signaling sent by the second terminal to the second S-CSCF after receiving the second INVITE signaling.

[0133] For example, in Figure 2 In step 201, when the first S-CSCF sends the first INVITE signaling to the first terminal, it needs to be forwarded through the first access network device, specifically: the first S-CSCF sends the first INVITE signaling to the first access network device; after receiving the first INVITE signaling sent by the first S-CSCF, the first access network device sends the first INVITE signaling to the first terminal.

[0134] It should be understood that here only the example of the second terminal sending the first INVITE signaling to the first terminal in step 201 is used for explanation. Other signaling exchanged between the second terminal and the first terminal in this application (for example, the 183Session Progress signaling in step 202 below, the PRACK signaling in step 203, the 200OK (PRACK) signaling in step 204, the UPDATE signaling in step 205, the 200OK (UPDATE) signaling in step 206, etc.) can also be transmitted in the same manner as step 201, and will not be elaborated later.

[0135] It should also be understood that if the first terminal does not open the ring back tone service, then Figure 2 The CAT-AS process will not be involved. For example, the forwarding of the first INVITE signaling will not go through CAT-AS.

[0136] The first INVITE signaling may indicate that the second terminal initiates a call (eg, the first call) to the first terminal.

[0137] It can be understood that the embodiment of the present application does not specifically limit the timing when the second terminal sends the first INVITE signaling. For example, when the calling user initiates a voice call, the second terminal sends the first INVITE signaling to the first terminal.

[0138] Optionally, the first INVITE signaling includes one or more of the following: sequence number (Cseq), Message ID, Response Code, and Call ID.

[0139] For example, the Cseq in the first INVITE signaling is: Cseq: 1 INVITE signaling, which means that the sequence number of the first INVITE signaling is 1.

[0140] Step 201 describes the network element nodes that the second terminal passes through when sending the first INVITE signaling to the first terminal. Generally speaking, when a network element node receives an INVITE signaling, it will reply with a 100Trying signaling to its previous network element node (or the network element node that sent the INVITE signaling to it) to notify its previous network element node that the INVITE signaling has been received. For example, after receiving the first INVITE signaling sent by the second terminal, the S-CSCF will immediately reply with a 100Trying signaling to the second terminal; after receiving the first INVITE signaling sent by the S-CSCF, the CAT-AS will immediately reply with a 100Trying signaling to the S-CSCF.

[0141] Step 202: The first terminal sends a 183 Session Progress signaling to the second terminal.

[0142] 183 Session Progress signaling may refer to session progress information, which includes the first handshake information in the three-way handshake (including the first handshake, the second handshake and the third handshake) between the first terminal and the second terminal. 183 Session Progress signaling may indicate that the first terminal and the second terminal are negotiating voice coding.

[0143] Exemplarily, 183 Session Progress signaling can be used to establish early media services, such as user-customized color ringback tone or ring tone.

[0144] Optionally, after the first terminal sends the 100Trying signaling to the second terminal, the first terminal sends the 183Session Progress signaling to the S-CSCF; after receiving the 183Session Progress signaling, the S-CSCF sends the 183Session Progress signaling received from the first terminal to the CAT-AS; after receiving the 183Session Progress signaling, the CAT-AS may send the received 183Session Progress signaling to the S-CSCF; the S-CSCF sends the 183SessionProgress signaling to the second terminal.

[0145] Optionally, the 183 Session Progress signaling includes one or more of the following: sequence number (Cseq), Message ID, Response Code, and Call ID.

[0146] For example, the Cseq in the 183 Session Progress signaling is: Cseq: 1 INVITE signaling, which means that the 183 Session Progress signaling corresponds to the INVITE signaling with a sequence number of 1, that is, the first INVITE signaling in step 201.

[0147] It should be noted that in step 201, the Call ID in the first INVITE signaling is different from the Call ID in the 183Session Progress signaling in step 202. The reason is that the session has not been established when the second terminal initiates the first INVITE signaling in step 201. Specifically, in step 201, from the perspective of the first terminal, the Call ID of the first INVITE signaling received by the first terminal is a value, and in step 202, when the first terminal sends the 183Session Progress signaling to the second terminal, it indicates that it is being processed. At this time, the Call ID included in the 183Session Progress signaling is another value (not used for the Call ID in the first INVITE signaling). In the signaling interaction process after step 202, the Call ID included in the signaling is consistent with the value of the Call ID included in the 183Session Progress signaling. In other words, the Call ID in the first INVITE signaling is not a valid Call ID, and the Call ID included in the 183Session Progress signaling is a valid Call ID.

[0148] Step 203: The second terminal sends a PRACK signaling to the first terminal.

[0149] The PRACK signaling may include the second handshake information in the three-way handshake. The PRACK signaling may indicate that the second terminal has received the 183 Session Progress signaling sent by the first terminal.

[0150] The process of the second terminal sending the PRACK signaling to the first terminal may refer to the process of the second terminal sending the first INVITE signaling to the first terminal in step 201. For the sake of brevity, the detailed sending process of the PRACK signaling is not repeated here.

[0151] Optionally, the PRACK signaling includes one or more of the following: Cseq, Message ID, ResponseCode, Call ID.

[0152] The signaling type or signaling range for the Cseq numbering of the embodiment of the present application is not specifically limited. In the same session, the Cseq numbering can be performed in sequence. For example, the Cseq of the first INVITE signaling in step 201 is 1, the Cseq of the PRACK signaling in step 203 is 2, the Cseq of the UPDATE signaling in step 205 is 3, and so on.

[0153] Exemplarily, the Cseq in the PRACK signaling is: Cseq 2PRACK; it is explained here that 1 is added to the Cseq 1 of the first INVITE signaling in step 201, and the Cseq of the PRACK is 2.

[0154] For example, the PRACK signaling has Message ID = IMS_SIP_PRACK; Response Code = INFORMAL_RESPONSE (0).

[0155] The Call ID in the PRACK signaling is consistent with the value of the Call ID contained in the 183 Session Progress signaling.

[0156] Step 204: The first terminal sends a 200OK (PRACK) signaling to the second terminal.

[0157] In response to the PRACK signaling sent by the second terminal, the first terminal sends a 200 OK (PRACK) signaling to the second terminal. It should be noted that 200 OK (PRACK) is the signaling that the first terminal replies to the second terminal in response to the PRACK signaling.

[0158] In the embodiments of the present application, for the convenience of expression and to distinguish different 200OK signalings, the signalings to which they are replied are marked in brackets after different 200OK signalings for distinction. Here, the 200OK signaling used to reply to the PRACK signaling is written as 200OK (PRACK) signaling, but the writing here is only for example. Other 200OK signalings with double brackets in the present application can also refer to this explanation.

[0159] 200OK (PRACK) signaling may indicate that PRACK signaling has been received.

[0160] The process of the first terminal sending the 200OK (PRACK) signaling to the second terminal can refer to the process of the first terminal sending the 183 Session Progress signaling to the second terminal in step 202. For the sake of brevity, the detailed sending process of 200OK (PRACK) is not repeated here.

[0161] Step 203 describes the numbering principle of the Cseq number. Accordingly, when the first terminal responds to a certain signaling, it can also carry the Cseq number of the signaling to be responded to in the signaling. For example, the Cseq that can be included in step 200OK (PRACK) is: Cseq 2PRACK, to indicate that the 200OK (PRACK) response is a PRACK numbered 2.

[0162] Step 205: The second terminal sends an UPDATE signaling to the first terminal.

[0163] The UPDATE signaling in step 205 may indicate that the second terminal has established a voice bearer, that is, the voice bearer is established. Those skilled in the art may understand that the access network device participates in the process of establishing the voice bearer.

[0164] Optionally, after the second terminal receives the 200OK (PRACK) signaling in step 204, the second terminal checks whether it has established the first voice bearer, that is, the first voice bearer has been established or the first voice bearer has been established. After the second terminal has received the voice dedicated bearer establishment instruction issued by the second radio access network device and has completed the establishment of the first voice bearer according to the voice dedicated bearer establishment instruction, an UPDATE signaling is sent to the first terminal, and the UPDATE signaling includes information indicating that the second terminal has established the first voice bearer.

[0165] After step 205, if the first terminal has not yet completed the establishment of the second voice bearer, the first terminal responds to the UPDATE signaling and returns a signaling indicating that the second voice bearer has not been established to the second terminal. In some embodiments, the information indicating that the second voice bearer has not been established will be carried in the 200OK (UPDATE) signaling (in the subsequent step 206) and sent to the second terminal. After step 205, if the first terminal has completed the establishment of the second voice bearer, the 200OK (UPDATE) signaling in the subsequent step 206 may carry information indicating that the second voice bearer has been established. The process of the second terminal sending the UPDATE signaling to the first terminal can refer to the process of the second terminal sending the first INVITE signaling to the first terminal in step 201. For the sake of brevity, the detailed sending process of the UPDATE signaling will not be repeated here.

[0166] Step 206: The first terminal sends a 200 OK (UPDATE) signaling to the second terminal.

[0167] The 200 OK (UPDATE) signaling may indicate that the UPDATE signaling has been received. For example, in step 206, the 200 OK (UPDATE) signaling may indicate that the first terminal has received the UPDATE signaling sent from the second terminal.

[0168] It should be noted that the signaling sent at this time is actually a 200OK signaling for replying to the UPDATE signaling. In the embodiment of the present application, in order to facilitate expression and distinguish different 200OK signaling, the signaling to which it replies is marked in brackets after the 200OK signaling for replying to different signalings for distinction. Here, the 200OK signaling for replying to the UPDATE signaling is written as 200OK (UPDATE) signaling, but the writing here is only for example. Other 200OK (UPDATE) signaling in the present application can also refer to this explanation.

[0169] Optionally, after the first terminal receives the UPDATE signaling sent by the second terminal, the first terminal sends a 200OK (UPDATE) signaling to the first S-CSCF; after receiving the 200OK (UPDATE) signaling, the first S-CSCF sends the 200OK (UPDATE) signaling received from the first terminal to the CAT-AS; after receiving the 200OK (UPDATE) signaling, the CAT-AS may send the received 200OK (UPDATE) signaling to the second S-CSCF; the second S-CSCF sends the 200OK (UPDATE) signaling to the second terminal.

[0170] The UPDATE signaling involved in step 205 and step 206 is the process of establishing a voice bearer between the second terminal and the first terminal. The UPDATE signaling may also have other functions.

[0171] Optionally, before step 207, the CAT-AS and the second terminal may negotiate to prepare for the subsequent playing of the ring back tone (not shown in the figure). For example, the CAT-AS may also send an UPDATE signaling to the second terminal, and then the second terminal replies with a 200OK (UPDATE) signaling to the CAT-AS. After these signaling interactions, it is indicated that the second terminal has negotiated with the CAT-AS to prepare for the playing of the ring back tone (for example, a channel has been established), so that the second terminal can start playing the ring back tone after receiving the 180Ringing signaling sent by the first terminal.

[0172] Step 207: The first terminal sends a 180Ringing signaling to the second terminal.

[0173] The 180Ringing signaling may be ringing information. After the first terminal has established a voice bearer, the 180Ringing signaling is sent to the second terminal.

[0174] The first terminal may enter the ringing state before sending the 180Ringing signaling. If the voice bearer between the first terminal and the network side has been established, the first terminal will enter the ringing state.

[0175] Optionally, after the first terminal sends the 180Ringing signaling, the call state of the first terminal is updated to the ringing state, and the first terminal starts ringing. The ringing state refers to the state in which when there is an incoming call, the user has not answered the call, and the called party's terminal device rings to remind the user of the incoming call; the ringtone when the ringing starts includes: vibration, color ringback tone, beep, personalized music, song, recording, video, etc., which are not limited here.

[0176] Optionally, step 207 includes: the first terminal sends a 180Ringing signaling to the first S-CSCF. After the first S-CSCF receives the 180Ringing signaling, the first S-CSCF sends a 180Ringing signaling to the CAT-AS. The CAT-AS replies to the 180Ringing signaling to the second S-CSCF, and carries SDP_A_CAT in the 180Ringing signaling. SDP_A_CAT is an SDP parameter related to the color ring tone, which is used to prepare for the subsequent playing of the color ring tone customized by the first terminal to the second terminal; in other words, SDP_A_CAT is used to notify the second terminal to prepare for playing the color ring tone, which will be played later. After receiving the 180Ringing signaling carrying SDP_A_CAT sent by the CAT-AS, the second S-CSCF sends a 180Ringing signaling carrying SDP_A_CAT to the second terminal. After the second terminal receives the 180Ringing signaling carrying the SDP_A_CAT, the call state of the second terminal is updated to the ringback tone state, and the second terminal starts to play the ringback tone. The ringback tone state refers to the state in which the calling party terminal sends a ringback tone to remind the user that the called party user has not answered the call when the call is successful but the called party user has not answered the call. Generally speaking, the ringback tone includes: vibration, color ringback tone, beep, personalized music, song, recording, video, etc. In the embodiment of the present application, the ringback tone played by the second terminal includes the color ringback tone customized by the first terminal.

[0177] Here, for the signaling of letters or words involved in the embodiments of the present application, the present application does not specifically limit the uppercase and lowercase letters of the English letters corresponding to the signaling, which can be all uppercase, all lowercase, or a combination of uppercase and lowercase letters (such as the first letter is uppercase and other letters are lowercase). For example, 180Ringing signaling can also be written as 180ringing signaling, 180RINGING signaling, etc.

[0178] Step 208: The second terminal sends a PRACK signaling to the CAT-AS.

[0179] The PRACK signaling indicates that the 180Ringing signaling has been received. For example, in step 208, the PRACK signaling indicates that the second terminal has received the 180Ringing signaling from the first terminal.

[0180] Exemplarily, PRACK signaling is used to indicate consent to play the ringback tone.

[0181] Optionally, step 208 includes: the second terminal sends a PRACK signaling to the second access network device ( Figure 2 The second access network device sends a PRACK signaling to the second S-CSCF; the second S-CSCF sends a PRACK signaling to the CAT-AS.

[0182] Optionally, in response to receiving the PRACK signaling, the CAT-AS starts playing the ringback tone (StartCAT media) after receiving the PRACK signaling. After the CAT-AS starts playing the ringback tone, the played ringback tone data will be transmitted to the second terminal through the network side, that is, the user of the second terminal can hear the ringback tone played by the CAT-AS.

[0183] It should be understood that the triggering condition for the CAT-AS to start playing the ring back tone is step 208, but this is only an example description, and the embodiments of the present application are not limited thereto. In fact, the CAT-AS can also perform early negotiation work or negotiate preparations for playing the ring back tone with the second terminal through other signaling (such as UPDATE signaling).

[0184] Step 209: The CAT-AS sends a 200 OK (PRACK) signaling to the second terminal.

[0185] The 200OK (PRACK) signaling is used to indicate that the PRACK signaling has been received. Optionally, step 209 includes: the CAT-AS sends a 200OK (PRACK) signaling to the second S-CSCF; after receiving the 200OK (PRACK) signaling sent by the CAT-AS, the second S-CSCF sends a 200OK (PRACK) signaling to the second terminal.

[0186] The first terminal receives the user's answering action. The answering action can be encapsulated as an answering event and transmitted to the system of the first terminal. The answering event refers to an event triggered when the user answers a call from the second terminal through some operations. The embodiment of the present application does not limit the specific way for the user to answer the call, including but not limited to: clicking the answer button on the screen, sliding the screen, pressing other peripherals (such as headphones) buttons, long pressing the fingerprint sensor, controlling the answering through the voice control function, etc.

[0187] In some embodiments, after the first terminal starts ringing, the user of the first terminal clicks Answer on the first terminal to answer the call.

[0188] Step 210: The first terminal sends a first 200 OK (INVITE) signaling to the CAT-AS.

[0189] Optionally, after the user answers the first call, in response to the INVITE signaling, the first terminal sends a first 200 OK (INVITE) signaling to the first S-CSCF.

[0190] It can be understood that, for a unified explanation here, 200 OK (INVITE) can also be written as 200 OK for INVITE, and the embodiments of the present application do not specifically limit this.

[0191] The first 200 OK (INVITE) signaling is used to indicate that the first terminal responds to the first INVITE signaling, or in other words, the first terminal replies 200 OK to the first INVITE signaling.

[0192] Optionally, after the user of the first terminal clicks to answer the call on the first terminal, the first terminal sends a first 200 OK (INVITE) signaling to the first S-CSCF.

[0193] It should be noted that, during the signaling interaction between the second terminal and the first terminal, there may be multiple INVITE signaling and 200OK (INVITE) signaling. For different INVITE signaling, the 200OK (INVITE) replied by the device can be distinguished by different sequence numbers or sequence identifiers.

[0194] Optionally, in some embodiments, the 200OK (INVITE) in step 210 includes Cseq: 1INVITE, which means that the 200OK (INVITE) replies to the INVITE with a sequence number of 1. Correspondingly, as described above, the first INVITE signaling in step 201 includes a sequence number (sequence, Cseq): 1, which means that the sequence number corresponding to the first INVITE signaling is 1.

[0195] Optionally, the first 200OK (INVITE) signaling may further include one or more of the following: Message ID, Response Code, Call ID.

[0196] The Message ID is used to indicate the name or type of the message. For example, the Message ID of the first 200OK (INVITE) signaling is IMS_SIP_INVITE, which means that the first 200OK (INVITE) signaling is a 200OK in response to the INVITE. In addition, according to the Cseq: 1INVITE included in the 200OK for INVITE signaling, it can be known that it is an INVITE signaling with a sequence number of 1.

[0197] Response Code is used to indicate the type of message response code, for example, the Response Code of the first 200 OK (INVITE) signaling is OK (200).

[0198] The Call ID is used to identify the session established for this call. Generally speaking, the Call IDs of the same session are the same.

[0199] After receiving the first 200 OK (INVITE) signaling sent by the first terminal, the first S-CSCF may send a 200 OK for INVITE signaling to the CAT-AS.

[0200] After receiving the first 200 OK (INVITE) signaling sent by the first S-CSCF, the CAT-AS may stop playing the color ring tone and reply with a first ACK signaling to the first S-CSCF.

[0201] Step 211: The CAT-AS sends a first ACK signaling to the first terminal.

[0202] The first ACK signaling is the first confirmation information, and the first ACK signaling may indicate that the first 200 OK (INVITE) signaling has been received. Optionally, in step 211, the first ACK signaling may indicate that the CAT-AS has received the first 200 OK (INVITE) signaling sent by the first S-CSCF.

[0203] Exemplarily, the first ACK signaling includes Cseq: 1ACK, which means that the first ACK signaling replies to the INVITE with sequence number 1. As mentioned above, the INVITE signaling in step 201 includes Cseq: 1, which means that the first ACK signaling replies to the first INVITE signaling in step 201 .

[0204] Optionally, the first ACK signaling also includes one or more of the following: Message ID, ResponseCode, Call ID.

[0205] Message ID is used to indicate the name or type of a message. For example, Message ID = IMS_SIP_ACK, indicating that the type of the first ACK signaling is ACK signaling.

[0206] Response Code is used to indicate the type of message response code. For example, Response Code=INFORMAL_RESPONSE(0) of the first ACK signaling indicates that the first ACK signaling is a response signaling.

[0207] The Call ID is used to identify the session established for the first call.

[0208] Optionally, step 211 includes: the CAT-AS sends a first ACK signaling to the first S-CSCF; the first S-CSCF sends a first ACK signaling to the first access network device ( Figure 2 (not shown); the first access network device sends a first ACK signaling to the first terminal.

[0209] Step 212: The CAT-AS sends a second INVITE signaling to the first terminal.

[0210] The process of CAT-AS sending the second INVITE signaling to the first terminal can refer to the process of CAT-AS sending the first ACK signaling to the first terminal in step 211, which is not repeated here for the sake of brevity. For example, after CAT-AS replies to the first S-CSCF with the first ACK signaling, it initiates the reINVITE process, that is, sends the second INVITE signaling to the first S-CSCF.

[0211] The second INVITE signaling may be a re-request message, and the second INVITE signaling may also be written as reINVITE signaling, and may be written as INVITE signaling, reinvite signaling, re-invite signaling, or other forms, and may also refer to descriptions of relevant protocols, etc., without specific limitation.

[0212] The Cseq included in the second INVITE signaling is different from the Cseq included in the first INVITE signaling in step 201. In addition, the second INVITE signaling here may include a Tag identifier, which is used to indicate that the second INVITE signaling here is not the first INVITE signaling sent in this call, and the Tag identifier may be located in the field corresponding to the information of the called terminal. That is, compared with the first INVITE signaling in step 201, the second INVITE signaling in step 212 has a Tag identifier added to distinguish it from the first INVITE signaling in step 201. The second INVITE signaling and the first INVITE signaling are two INVITE signalings in the same call.

[0213] Step 213: The first terminal sends a second 200 OK (INVITE) signaling to the CAT-AS.

[0214] The second 200OK (INVITE) signaling is used to indicate that the first terminal responds to the second INVITE signaling, or in other words, the second 200OK (INVITE) signaling is the first terminal's reply 200OK to the second INVITE signaling. It can be understood that the second 200OK (INVITE) signaling can also be written as 200OK (reINVITE) signaling, 200OK signaling, 200OK (REINVITE) signaling, 200OK for reINVITE and other forms, or can also refer to the writing of related protocols.

[0215] As described in the above step 210, for different INVITE signalings, the INVITE signaling to which the 200OK (INVITE) signaling replied by the device corresponds can be distinguished by different sequence numbers or sequence identifiers.

[0216] Optionally, in some embodiments, the second 200OK (INVITE) signaling in step 213 includes Cseq: 4INVITE, indicating that the second 200OK (INVITE) signaling replies to the INVITE with sequence number 4. Correspondingly, the second INVITE signaling in step 212 includes Cseq: 4, indicating that the sequence number corresponding to the second INVITE signaling is 4.

[0217] Optionally, the second 200OK (INVITE) signaling may further include one or more of the following: Message ID, Response Code, Call ID.

[0218] The Message ID is used to indicate the name or type of the message. For example, the Message ID of the second 200OK (INVITE) signaling is IMS_SIP_INVITE, which means that the second 200OK (INVITE) signaling is a 200OK in response to the second INVITE signaling. In addition, according to the Cseq: 4INVITE included in the second 200OK (INVITE) signaling, it can be known that it is directed to the INVITE signaling with sequence number 4.

[0219] Response Code is used to indicate the type of message response code, for example, Response Code = OK (200) of the second 200 OK (INVITE) signaling. Call ID is used to identify the session established for this call.

[0220] Step 214: The CAT-AS sends an UPDATE signaling to the second terminal.

[0221] The UPDATE signaling is used by CAT-AS to end or close the CRBT in the first call as a reminder to close the CRBT. For example, the UPDATE signaling is used to set the port number corresponding to the audio media to zero to close the port. The end of the playback can be known through the UPDATE signaling sent by CAT-AS. It should be noted that before step 214, CAT-AS has stopped playing the CRBT. After stopping playing the CRBT, the second terminal will also stop playing. However, it is still necessary to end the CRBT process through UPDATE signaling so as to set the corresponding port number to zero.

[0222] Optionally, step 214 includes: the CAT-AS sends an UPDATE signaling to the second S-CSCF; the second S-CSCF sends an UPDATE signaling to the second access network device; and the second access network device sends an UPDATE signaling to the second terminal.

[0223] Step 215: The second terminal sends a 200 OK (UPDATE) signaling to the CAT-AS.

[0224] The 200OK (UPDATE) signaling may indicate that the UPDATE signaling has been received, or that the second terminal replies 200OK to the UPDATE signaling.

[0225] Optionally, step 215 includes: the second terminal sends a 200OK (UPDATE) signaling to the second access network device; the second access network device sends a 200OK (UPDATE) signaling to the second S-CSCF; the second S-CSCF sends a 200OK (UPDATE) signaling to the CAT-AS.

[0226] Step 216: The CAT-AS sends a first 200 OK (INVITE) signaling to the second terminal.

[0227] Here, the purpose of the CAT-AS sending the first 200 OK (INVITE) signaling to the second terminal is to transfer the answering action of the first terminal to the second terminal.

[0228] It should be noted that only after the first terminal replies to the second 200OK (INVITE) signaling (i.e., step 213), CAT-AS will transmit the first 200OK (INVITE) signaling fed back by the first terminal after the answering action to the calling side (for example, through step 216, the first 200OK (INVITE) signaling is sent to the second terminal). Then, after the second terminal receives the first 200OK (INVITE) signaling, it replies with the second ACK signaling to the first terminal; when the first terminal receives the second ACK signaling, the first terminal and the second terminal can transmit voice data, or in other words, the user of the first terminal and the user of the second terminal can talk.

[0229] Step 217: The second terminal sends a second ACK signaling to the first terminal.

[0230] The second ACK signaling may indicate that the second terminal has received the first 200 OK (INVITE) signaling sent by the first terminal.

[0231] The process of the second terminal sending the second ACK signaling to the first terminal may refer to the process of the second terminal sending the first INVITE signaling to the first terminal in step 201. For the sake of brevity, the detailed sending process of the second ACK signaling is not repeated here.

[0232] The second ACK signaling may be second confirmation information. The second ACK signaling is used to indicate that the first 200 OK (INVITE) signaling has been received. Optionally, in step 217, the second ACK signaling is used to indicate that the second terminal has received the first 200 OK (INVITE) signaling sent by the first terminal to the second terminal.

[0233] It can be understood that after step 217, a voice packet can be sent between the second terminal and the first terminal, so that the user of the second terminal and the user of the first terminal can have a normal voice call. The voice packet can be voice data. For example, the second terminal sends voice data to the first terminal. For another example, the first terminal sends voice data to the second terminal.

[0234] It can also be understood that there is no sequence or trigger relationship between the first terminal sending voice data to the second terminal and the second terminal sending voice data to the first terminal, and the order of the two can be interchanged. During a call, the first terminal and the second terminal can exchange voice packets multiple times, and the embodiment of the present application does not limit this.

[0235] It can also be understood that when the call ends, the first terminal or the second terminal may also initiate a session end message, such as a BYE message; accordingly, the opposite terminal may send a session end response message, such as an ACK (BYE) message.

[0236] It is understandable. Figure 2 The step numbers shown in the figure are merely exemplary descriptions and do not limit the scope of protection of the embodiments of the present application.

[0237] Figure 2 The figure shows the process after the first terminal activates the ring back tone service. If the first terminal does not activate the ring back tone service, then after the first terminal clicks to answer and receives the first ACK signaling, it can enter into a call with the second terminal. In addition, if the first terminal does not activate the ring back tone service, then Figure 2 After the CRBT service is activated, both the first terminal side and the network side add the relevant process of the second INVITE signaling (for example Figure 2 The dotted box indicates the main signaling process on the network side after subscribing to the ring back tone service).

[0238] Therefore, users who have activated color ringback tone are prone to the problem of silent calls, which is mainly manifested as a single-channel or silent call. The reason is that when the user of the first terminal clicks on the answer action, the first terminal does not receive the first ACK signaling returned by the network (for example, the first S-CSCF), but receives the second INVITE signaling. According to the SIP protocol, if the first terminal receives the second INVITE signaling before receiving the first ACK signaling, it will reply 491 to the network. After receiving 491, the network will retransmit the second INVITE signaling. However, since the first terminal did not receive the first ACK signaling, it will continue to reply 491 to the network side, so that the answering action of the first terminal cannot be transmitted to the second terminal. The user of the first terminal will start talking after clicking on the answer, and since the second terminal does not receive the answering instruction, the sound of the second terminal cannot be transmitted to the first terminal, resulting in a single-channel or silent situation, which seriously affects the user's call experience. The following will be combined with Figure 3 The signaling interaction process in describes the problem scenario.

[0239] refer to Figure 3 , Figure 3 The figure shows the signaling interaction process when the first terminal does not receive the first ACK signaling. It should be understood that Figure 2 The various messages involved in the steps shown in the figure may be existing messages in the SIP protocol or newly defined messages, and no specific limitation is made to this. It should also be understood that Figure 3 Some of the signaling or messages involved in Figure 2 Similar to the above, please refer to Figure 2 The meaning or explanation of the same signaling or terminology will not be repeated here.

[0240] Figure 2 and Figure 3 The difference is that Figure 3The first ACK signaling in step 311 is lost, or the first terminal does not receive the first ACK signaling from the network. Figure 3 As shown, including:

[0241] Step 301 to step 314; for example, Figure 3 Steps 301 to 314 in Figure 2 Steps 201 to 214 are the same as in the above. For related descriptions, please refer to the previous text. Figure 2 The contents of steps 301 to 314 are not repeated here.

[0242] In step 311, the first ACK signaling sent by the CAT-AS to the first S-CSCF is not sent normally, thereby causing the first S-CSCF to fail to send the first ACK signaling to the first terminal in step 311 (or fail to send it successfully);

[0243] Alternatively, in step 311, the first ACK signaling sent by the CAT-AS to the first S-CSCF has been sent normally, while the first ACK signaling sent by the first S-CSCF to the first terminal in step 311 is lost (or the first terminal does not receive the first ACK signaling sent by the first S-CSCF);

[0244] Alternatively, in step 311, the first ACK signaling sent by the CAT-AS to the first S-CSCF and the first ACK signaling sent by the first S-CSCF to the first access network device are both sent normally, while the first ACK signaling sent by the first access network device to the first terminal is lost (or the first terminal does not receive the first ACK signaling sent by the first access network device).

[0245] Regardless of which of the above methods is used, the final result is: in step 311, the first terminal does not receive the first ACK signaling sent by the network side.

[0246] Step 312: The CAT-AS sends a second INVITE signaling to the first terminal.

[0247] Step 312 is issued when the first terminal does not receive the first ACK signaling. Figure 2 The description of step 212 in , for the sake of brevity, is not repeated here.

[0248] For the first terminal, after the user of the first terminal answers the call, if the first terminal does not receive the first ACK signaling but receives the second INVITE signaling, the first terminal replies with a 491 signaling, ie, executes step 313 .

[0249] Step 313: When the first terminal does not receive the first ACK signaling, the first terminal sends a 491 signaling to the CAT-AS.

[0250] 491 signaling can indicate a request pending, which means that a dependent request is being processed in the same session (for example, Figure 3 Alternatively, it can be understood that, since the first terminal does not receive the first ACK signaling (used to respond to the first 200 OK (INVITE) signaling sent at step 310), the first terminal responds to the received second INVITE signaling by replying 491.

[0251] It can be understood that if the first terminal does not receive the first ACK signaling, then even if the first terminal receives multiple second INVITE signalings, it will reply with a 491 signaling each time.

[0252] Exemplarily, step 313 includes: the first terminal sends a 491 signaling to the first S-CSCF; after receiving the 491 signaling sent by the first terminal, the first S-CSCF sends a 491 signaling to the CAT-AS. Subsequently, the first S-CSCF retransmits the second INVITE signaling. Since the first terminal has not received the first ACK signaling, it continues to reply with a 491 signaling, thereby repeatedly executing steps 312 to 313, resulting in the inability to execute steps 314 to 317.

[0253] in, Figure 3 Steps 314 to 317 in Figure 2 The steps 214 to 217 are the same as those in FIG. 1 , and the detailed description can be referred to in Figure 2 The description of step 214 to step 217 in the embodiment is not repeated here for the sake of brevity.

[0254] Since steps 314 to 317 cannot be executed, the answering action of the called party cannot be transmitted to the calling party, so the voice of the calling party is not allowed to be transmitted to the called party, resulting in a single call or silent uplink and downlink; or, the user of the first terminal cannot hear the voice of the user of the second terminal and will hang up the phone, affecting the call experience. Figure 3 In the example, after the user of the first terminal clicks the answer action, he cannot hear the voice of the user of the second terminal.

[0255] In view of this, an embodiment of the present application proposes a method for establishing a call connection between a second terminal and a first terminal. When the user of the first terminal clicks the answer operation, the first terminal determines whether the second INVITE signaling is received. If the second INVITE signaling is received, the first terminal assumes that the network side has replied to the first ACK signaling, and responds normally to the 200OK signaling for the second INVITE signaling, or the second 200OK (INVITE) signaling, so as to execute subsequent processes (such as Figure 3 Steps 314 to 317 in the above can continue to be executed), so that the first terminal and the second terminal can successfully establish a call connection. Figure 4 The process in is described.

[0256] refer to Figure 4 , Figure 4 The signaling interaction process when the first terminal does not receive the first ACK signaling in the embodiment of the present application is shown. It should be understood that Figure 4 The various messages involved in the steps shown in the figure may be existing messages in the SIP protocol or newly defined messages, and no specific limitation is made to this. It should also be understood that Figure 4 Some of the signaling or messages involved in Figure 2 Similar to the above, please refer to Figure 2 The meaning or explanation of the same signaling will not be repeated. It should also be understood that Figure 4 The process shown can be applied to Figure 1 The scenario shown. For example, Figure 4 The first S-CSCF shown in FIG. 1 may be Figure 1 An example of a core network device in the first network side device; Figure 4 The second S-CSCF shown in FIG. 1 may be Figure 1 An example of a core network device in the second network side device; Figure 4 The CAT-AS shown in the figure can be Figure 1 An example of a ring back tone server in ; Figure 4 The second terminal in can be Figure 1 The second terminal in; Figure 4 The first terminal in can be Figure 1 The first terminal in.

[0257] In some embodiments, when the user of the first terminal clicks to answer the call, if the first terminal does not receive the first ACK signaling, Figure 4 and Figure 3 The difference is that if the first terminal receives the second INVITE signaling in step 412, it will still reply with the second 200OK (INVITE) signaling. Figure 4 As shown, including:

[0258] Step 401 to step 410; for example, Figure 4 Steps 401 to 410 in Figure 2 Steps 201 to 210 are the same as in the above. For related descriptions, please refer to the previous text. Figure 2 The contents of step 401 to step 410 are not repeated here.

[0259] The description of step 411 can refer to Figure 3 For the sake of brevity, the description of step 311 is omitted here.

[0260] Step 412: The CAT-AS sends a second INVITE signaling to the first terminal.

[0261] In an embodiment of the present application, if the first terminal does not receive the first ACK signaling but receives the second INVITE signaling, in this case, the first terminal will assume that the first ACK signaling has been received, so it directly processes after receiving the second INVITE signaling, for example, replies with the second 200OK (INVITE) signaling to the first S-CSCF, that is, executes step 413.

[0262] Step 413: The first terminal sends a second 200 OK (INVITE) signaling to the CAT-AS.

[0263] It is understandable that the timing of the first S-CSCF sending the second INVITE signaling to the first terminal is uncertain. It may be sent to the first terminal immediately after receiving the second INVITE signaling sent by the CAT-AS, or it may be delayed for some reason. In order to avoid the first terminal always waiting for the first S-CSCF to send the second INVITE signaling, optionally, a preset time length can be set on the first terminal side to constrain the time the first terminal waits for the second INVITE signaling, or the effective time of the embodiment of the present application.

[0264] The embodiment of the present application does not limit the specific duration of the preset duration. The preset duration can be a reasonable duration flexibly set based on a priori value or actual demand. Optionally, in some embodiments, the first terminal receives the second INVITE signaling within the preset duration, and determines whether the first ACK signaling is received after receiving the second INVITE signaling. If the first ACK signaling is not received, the first terminal sends a second 200OK signaling.

[0265] It should be noted that after receiving the second INVITE signaling, Figure 4 The step of the first terminal determining whether the first ACK signaling is received is implemented within a preset time period, but the embodiment of the present application is not limited thereto. For example, the step of the first terminal determining whether the first ACK signaling is received may also occur outside the preset time period.

[0266] It can be understood that the preset duration can be achieved through timers, timers, etc. in actual processes.

[0267] Optionally, in some embodiments, after the first terminal receives the user's answering action or sends the first 200OK (INVITE) signaling, the first timer starts timing (or starts the first timer); when the first terminal receives the second INVITE signaling, it determines whether the first timer has timed out, and determines whether the first ACK signaling has been received. If the first timer has not timed out (indicating that the second INVITE signaling is received during the operation of the first timer) and the first ACK signaling is not received, the first terminal sends the first S-CSCF to reply to the second 200OK (INVITE) signaling, that is, execute step 413. The first timer has not timed out means that the timing duration of the first timer is less than or equal to the preset duration.

[0268] Of course, after the first timer times out, if the first terminal does not receive the first ACK signaling, nor the second INVITE signaling sent by the S-CSCF, then the first terminal performs the corresponding execution according to the process in the standard protocol. In addition, after the first timer times out, if the first terminal still does not receive the first ACK signaling, but receives the second INVITE signaling sent by the first S-CSCF, since the second INVITE signaling is received after the running time of the first timer has exceeded, the first terminal replies with a 491 signaling.

[0269] In summary, the first timer is set to constrain the duration of the first terminal waiting for the second INVITE signaling. In addition, the embodiment of the present application does not specifically limit the timing duration of the first timer. The timing duration of the first timer can be the above-mentioned preset duration. Exemplarily, the duration of the first timer can be set to 3 seconds.

[0270] In addition, the embodiment of the present application does not limit the specific timing of the first terminal starting the first timer. For example, the first terminal may start the first timer after sending the first 200OK (INVITE) signaling to the first S-CSCF. For another example, the first terminal may start the first timer after the user clicks to answer the call.

[0271] In the embodiment of the present application, in the case where the first ACK signaling sent by the first S-CSCF is not received but the second INVITE signaling sent by the first S-CSCF is received, compared with Figure 3The first terminal sends a 491 signaling to the first S-CSCF. After receiving the second INVITE signaling sent by the first S-CSCF, the first terminal replies with a second 200OK (INVITE) signaling to the first S-CSCF, so that subsequent steps can continue to be executed, for example, executing steps 414 to 417.

[0272] The subsequent steps 414 to 417 are Figure 2 The normal process is the same as in the above. For detailed description, please refer to Figure 2 The description of step 214 to step 217 in the embodiment is not repeated here for the sake of brevity.

[0273] Optionally, in some embodiments, after step 413, or after the first terminal responds to the first S-CSCF with the second 200 OK (INVITE) signaling, if the first terminal receives other signaling, then the first terminal may respond normally to the other received signaling and no longer respond to the 491 signaling. For example, after step 413, Figure 4 The signaling interaction process also includes:

[0274] Step a, the first terminal receives the Y signaling; step b, the first terminal responds to the Y signaling normally.

[0275] The embodiment of the present application does not specifically limit the specific content of the Y signaling, nor does it specifically limit the initiator of the Y signaling. For example, the Y signaling can be another INVITE signaling sent by the S-CSCF to the first terminal.

[0276] It should be noted that the reason why the first terminal can respond to the Y signaling normally after step 413 is that the first terminal has replied to the second 200OK (INVITE) signaling to the first S-CSCF in step 413. The first terminal will infer that the first S-CSCF has sent the first ACK signaling, and it assumes that it has received the first ACK signaling sent by the first S-CSCF. There is no request pending (Request Pending), so it will not reply to the 491 signaling, but will respond to the Y signaling normally.

[0277] It should be understood that the above Figures 2 to 4 The process in the example is described by taking some processes in the Session Initiation Protocol SIP as an example. In fact, the process of establishing a call connection between the second terminal and the first terminal may include more processes.

[0278] It should also be understood that the above Figures 2 to 4 The message or signaling involved in the above may be a message or signaling in SIP, and the relevant specific explanation may refer to the description in SIP. The above message description is only a brief introduction.

[0279] In order to facilitate understanding of the implementation logic of the embodiment of the present application from the first terminal side, the following Figure 5 Describe. Figure 5 , Figure 5 The method flow executed by the first terminal is shown. It should be understood that Figure 5 The first terminal shown in may be Figure 4 It should also be understood that Figure 5 For relevant terms or explanations involved, please refer to the previous article Figure 4 For the sake of brevity, the description is not repeated here. Figure 5 As shown, including:

[0280] Step 501: When a second terminal initiates a first call to the first terminal, the first terminal receives a first INVITE signaling from the second terminal.

[0281] The explanation of step 501 can be found in the previous text. Figure 2 In some embodiments, step 501 may be Figure 4 Step 401 in .

[0282] Step 502: After detecting the user's answering action, in response to the first INVITE signaling, the first terminal sends a first 200 OK (INVITE) signaling.

[0283] Optionally, the first terminal sends a first 200 OK (INVITE) signaling to the S-CSCF. In some embodiments, step 502 may be Figure 4 Step 410 or Figure 2 The explanation of the first 200 OK (INVITE) signaling can refer to the explanation of the above step 210, and for the sake of brevity, it will not be repeated here.

[0284] Step 503: The first terminal receives the second INVITE signaling.

[0285] Exemplarily, based on the first call, the first terminal receives a second INVITE signaling, the second INVITE signaling includes a first identifier, and the INVITE signaling does not include the first identifier. The first identifier may be the Tag identifier mentioned above, and its meaning is not repeated here for brevity.

[0286] If the first terminal receives the second INVITE signaling, step 504 is executed.

[0287] As described above, optionally, in some embodiments, the first terminal may detect whether the first ACK signaling is received by starting the first timer. For related descriptions, reference may be made to the above text and will not be repeated here.

[0288] Step 504-1: After receiving the second INVITE signaling, the first terminal determines whether the first ACK signaling is received.

[0289] Optionally, in some embodiments, Figure 5 The process may also include: step 504-2, when the first ACK signaling is not received, it may further determine whether (the time from sending the first 200OK signaling to the current moment, or the time from detecting the user's answering action to the current moment) exceeds the preset time.

[0290] The embodiment of the present application does not specifically limit the specific implementation method in step 504-2. For example, a first timer may be introduced to determine whether the preset time is exceeded by judging the relationship between the timing duration of the first timer and the preset time.

[0291] Step 505: The first terminal sends a second 200 OK (INVITE) signaling. In some embodiments, step 505 may be Figure 4 Step 413 in .

[0292] Step 506: The first terminal sends a 491 signaling. In some embodiments, step 505 may be Figure 3 Step 313 in .

[0293] Figure 5 For the description of some terms or signaling involved, please refer to the previous article. Figure 2 or Figure 4 Description in .

[0294] It should be noted that Figures 2 to 4 The interaction diagram shown in the figure is only for ease of understanding, and is not intended to limit the embodiments of the present application to the examples shown in the figure. Figures 2 to 4 The examples in can be equivalently transformed to obtain more implementation methods.

[0295] Combination of the above Figures 1 to 5 , describes in detail the method for call connection provided by the embodiment of the present application. Figures 6 to 8 It should be understood that the device for call connection in the embodiment of the present application can execute the various methods for call connection in the aforementioned embodiment of the present application, that is, the specific working process of the following various products can refer to the corresponding process in the aforementioned method embodiment.

[0296] Figure 6 FIG. 6 is a schematic block diagram of a device 600 for call connection according to an embodiment of the present application. It should be understood that the device 600 may execute Figures 2 to 5 The method for call connection shown is a method executed by the first terminal.

[0297] like Figure 6 As shown, the device 600 includes: a transceiver unit 610 and a processing unit 620.

[0298] Exemplarily, the apparatus 600 is used to perform Figure 4 and Figure 5 The method is performed by a first terminal in the embodiment of the present invention. The device subscribes to a color ring back tone service.

[0299] In some embodiments, the transceiver unit 610 is used to receive a first INVITE signaling from the second terminal when the second terminal initiates a first call to the first terminal;

[0300] The transceiver unit 610 is further configured to send a first 200OK signaling in response to the first INVITE signaling after detecting the user's answering action;

[0301] The transceiver unit 610 is further configured to receive a second INVITE signaling based on the first call, the second INVITE signaling includes a first identifier, the first INVITE signaling does not include the first identifier, and the first terminal does not receive a first ACK signaling after sending the first 200OK signaling and before receiving the second INVITE signaling;

[0302] The transceiver unit 610 is further configured to send a second 200OK signaling in response to the second INVITE signaling.

[0303] Optionally, as an embodiment, the processing unit 620 is configured to determine whether the first ACK signaling is received after receiving the second INVITE signaling;

[0304] When the first ACK signaling is not received, the transceiver unit 610 is called to send the second 200OK signaling.

[0305] Optionally, as an embodiment, the processing unit 620 is further configured to determine whether the first timer has timed out;

[0306] When the first ACK signaling is not received and the first timer has not timed out, the transceiver unit 610 is called to send the second 200OK signaling. The first timer has not timed out, which means that the timing duration of the first timer is less than or equal to the preset duration. The timing duration of the first timer refers to the time between the moment when the user's answering action is detected and the current moment, or the time between the moment when the first 200OK signaling is sent and the current moment.

[0307] Optionally, as an embodiment, the processing unit 620 is further used to call the transceiver unit 610 to send a 491 signaling when the first ACK signaling is not received and the first timer times out.

[0308] Optionally, as an embodiment, the transceiver unit 610 is further used to: receive a second ACK signaling from the second terminal; after receiving the second ACK signaling, receive voice data from the second terminal, or send voice data to the second terminal.

[0309] Optionally, as an embodiment, the transceiver unit 610 is further configured to send a 180Ringing signaling to the second terminal after receiving the first INVITE signaling.

[0310] Optionally, as an embodiment, the transceiver unit 610 is further configured to receive an UPDATE signaling from the second terminal; and send a third 200OK signaling in response to the UPDATE signaling.

[0311] Optionally, as an embodiment, the first 200OK signaling is sent after starting to play the color ring tone; the second INVITE signaling is received after stopping to play the color ring tone.

[0312] In a possible example, the transceiver unit 610 may be implemented by a transceiver. The processing unit 620 may be implemented by a processor or a processing unit. It should be understood that the above-mentioned device 600 is embodied in the form of a functional unit. The term "unit" here may be implemented in the form of software and / or hardware, and the embodiments of the present application do not specifically limit this.

[0313] For example, a "unit" may be a software program, a hardware circuit, or a combination of the two that implements the above functions. The hardware circuit may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor, or a group processor, etc.) and a memory that executes one or more software or firmware programs, an integrated logic circuit, and / or other suitable devices that can provide the above functions.

[0314] Figure 7 is a schematic block diagram of a communication device according to an embodiment of the present application. The communication device embodiment corresponds to the method embodiment, and similar descriptions can refer to the method embodiment. Figure 7 The communication device 700 shown can be used to support execution corresponding to Figures 2 to 5The communication device 700 includes: a processor 710, a memory 720, and a transceiver 730. The processor 710, the memory 720, and the transceiver 730 are connected by communication. The memory 720 stores instructions. The processor 710 is used to execute the instructions stored in the memory 720. The transceiver 730 is used to perform specific signal transmission and reception under the drive of the processor 710.

[0315] In one implementation, the communication device 700 may correspond to the first terminal in the above method embodiment, and may be used to execute the various steps and / or processes executed by the first terminal in the above method embodiment. The processor 710 may be used to execute instructions stored in the memory 720, and when the processor 710 executes the instructions stored in the memory, the processor 710 is used to execute the various steps and / or processes of the above method embodiment corresponding to the first terminal.

[0316] The processor 710 is configured to call the transceiver 730 to receive the first INVITE signaling from the second terminal when the second terminal initiates the first call to the first terminal; after detecting the user's answering action, in response to the first INVITE signaling, call the transceiver 730 to send a first 200OK signaling; based on the first call, call the transceiver 730 to receive the second INVITE signaling, the second INVITE signaling includes a first identifier, the first INVITE signaling does not include the first identifier, and the first terminal does not receive the first ACK signaling after sending the first 200OK signaling and before receiving the second INVITE signaling; in response to the second INVITE signaling, call the transceiver 730 to send a second 200OK signaling.

[0317] The various components in the communication device 700 are connected by communication, that is, the processor 710, the memory 720 and the transceiver 730 communicate with each other through the internal connection path to transmit control and / or data signals. The above method embodiments of the present application can be applied to the processor, or the steps of the above method embodiments are implemented by the processor. The processor may be an integrated circuit chip with signal processing capabilities. In the implementation process, the steps of the above method embodiments can be completed by hardware integrated logic circuits in the processor or software instructions. The above processor can be a central processing unit (CPU), a network processor (NP) or a combination of CPU and NP, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The various methods, steps and logic block diagrams disclosed in this application can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0318] The transceiver 730 may include a transmitter and a receiver. The transceiver 730 may further include an antenna, and the number of antennas may be one or more. The processor 710, the memory 720, and the transceiver 730 may be devices integrated on different chips. For example, the processor 710 and the memory 720 may be integrated in a baseband chip, and the transceiver 730 may be integrated in a radio frequency chip. The processor 710, the memory 720, and the transceiver 730 may also be devices integrated on the same chip. This application does not limit this.

[0319] The transceiver 730 may also be a communication interface, such as an input / output interface. The transceiver 730, the processor 710, and the memory 720 may all be integrated into the same chip, such as a baseband chip.

[0320] For example, in the embodiment of the present application, the processor 710 may be composed of a processing unit (such as Figure 6 The processing unit 620 in the embodiment is implemented, the memory 720 can be implemented by a storage module, and the transceiver 730 can be implemented by a transceiver unit (such as Figure 6 The transceiver unit 610 in is implemented.

[0321] The method for call connection provided in the embodiment of the present application can be applicable to mobile phones, tablet computers, desktops, laptops, notebook computers, ultra-mobile personal computers (UMPC), handheld computers, netbooks, personal digital assistants (PDA), wearable electronic devices, smart watches and other electronic devices that can support calls. The UE mentioned above can also belong to such electronic devices. Figure 8 The hardware structure of the first terminal is described by way of example.

[0322] Figure 8 A structural schematic diagram of an electronic device 1000 suitable for the present application is shown.

[0323] The electronic device 1000 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone interface 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0324] It should be noted that Figure 8 The structure shown does not constitute a specific limitation on the electronic device 1000. In other embodiments of the present application, the electronic device 1000 may include Figure 8 The electronic device 1000 may include more or fewer components than those shown. Figure 8A combination of some of the components shown, or the electronic device 1000 may include Figure 8 Subassemblies of some of the components shown. Figure 8 The components shown may be implemented in hardware, software, or a combination of software and hardware.

[0325] The processor 110 may include one or more processing units. For example, the processor 110 may include at least one of the following processing units: an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and a neural-network processing unit (NPU). Different processing units may be independent devices or integrated devices.

[0326] The controller can generate operation control signals according to the instruction operation code and timing signal to complete the control of instruction fetching and execution.

[0327] The processor 110 may also be provided with a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory may store instructions or data that the processor 110 has just used or cyclically used. If the processor 110 needs to use the instruction or data again, it may be directly called from the memory. This avoids repeated access, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0328] In some embodiments, the processor 110 may include one or more interfaces. For example, the processor 110 may include at least one of the following interfaces: an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a SIM interface, and a USB interface.

[0329] In some embodiments, when the second terminal initiates a first call to the electronic device 1000, the processor 110 is used to call the communication module to receive a first INVITE signaling from the second terminal; after detecting the user's answering action, in response to the first INVITE signaling, send a first 200OK signaling; based on the first call, receive a second INVITE signaling, the second INVITE signaling includes a first identifier, the first INVITE signaling does not include the first identifier, and the first terminal does not receive a first ACK signaling after sending the first 200OK signaling and before receiving the second INVITE signaling; in response to the second INVITE signaling, send a second 200OK signaling.

[0330] Figure 8 The connection relationship between the modules shown is only a schematic illustration and does not constitute a limitation on the connection relationship between the modules of the electronic device 1000. Optionally, the modules of the electronic device 1000 may also adopt a combination of multiple connection modes in the above embodiments.

[0331] The wireless communication function of the electronic device 1000 can be implemented through components such as the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem processor, and the baseband processor.

[0332] The electronic device 1000 can realize the display function through the GPU, the display screen 194 and the application processor. The GPU is a microprocessor for image processing, which connects the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 110 may include one or more GPUs, which execute program instructions to generate or change display information.

[0333] The display screen 194 can be used to display images or videos. The display screen 194 includes a display panel. The display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a mini light-emitting diode (Mini LED), a micro light-emitting diode (Micro LED), a micro OLED (Micro OLED) or a quantum dot light emitting diode (QLED). In some embodiments, the electronic device 1000 may include 1 or N display screens 194, where N is a positive integer greater than 1.

[0334] The electronic device 1000 can realize the shooting function through the ISP, the camera 193, the video codec, the GPU, the display screen 194 and the application processor.

[0335] The digital signal processor is used to process digital signals, and can process not only digital image signals but also other digital signals. For example, when the electronic device 1000 is selecting a frequency point, the digital signal processor is used to perform Fourier transform on the frequency point energy.

[0336] ISP is used to process the data fed back by camera 193. For example, when taking a photo, the shutter is opened, and the light is transmitted to the camera photosensitive element through the lens. The light signal is converted into an electrical signal, and the camera photosensitive element transmits the electrical signal to ISP for processing and converts it into an image visible to the naked eye. ISP can also perform algorithm optimization on the noise, brightness, and skin color of the image. ISP can also optimize the exposure, color temperature and other parameters of the shooting scene. In some embodiments, ISP can be set in camera 193.

[0337] The wireless communication function of the electronic device can be implemented through antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, modem processor and baseband processor.

[0338] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the electronic device can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve the utilization of the antennas. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antenna can be used in combination with a tuning switch.

[0339] The mobile communication module 150 can provide solutions for wireless communications including 2G / 3G / 4G / 5G, etc., applied to electronic devices. The mobile communication module 150 may include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves from the antenna 1, and filter, amplify, and process the received electromagnetic waves, and transmit them to the modulation and demodulation processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modulation and demodulation processor, and convert it into electromagnetic waves for radiation through the antenna 1. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the processor 110. In some embodiments, at least some of the functional modules of the mobile communication module 150 can be set in the same device as at least some of the modules of the processor 110.

[0340] In some embodiments, the electronic device initiates or receives a call request through the mobile communication module 150 and the antenna 1 .

[0341] The wireless communication module 160 can provide wireless communication solutions including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), etc., which are applied to electronic devices. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via the antenna 3, modulates the frequency of the electromagnetic wave signal and performs filtering, and sends the processed signal to the processor 110. The wireless communication module 160 can also receive the signal to be sent from the processor 110, modulate the frequency of it, amplify it, and convert it into electromagnetic waves for radiation through the antenna 2.

[0342] Optionally, in one implementation, the audio module 170 may include a speaker 170A, a receiver 170B, a microphone 170C, and an earphone jack 170D; the sensor module 180 may include a touch sensor 180K, and may also include at least one of a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, an ambient light sensor 180L, and a bone conduction sensor 180M.

[0343] The electronic device 1000 can implement audio functions such as music playing and recording through the audio module 170, the speaker 170A, the receiver 170B, the microphone 170C, the headphone jack 170D, and the application processor.

[0344] The audio module 170 is used to convert digital audio information into analog audio signal output, and is also used to convert analog audio input into digital audio signals. The audio module 170 can also be used to encode and decode audio signals. In some embodiments, the audio module 170 can be arranged in the processor 110, or some functional modules of the audio module 170 can be arranged in the processor 110.

[0345] The speaker 170A, also called a "speaker", is used to convert an audio electrical signal into a sound signal. The electronic device 1000 can listen to music or listen to a hands-free call through the speaker 170A.

[0346] The receiver 170B, also called a "earpiece", is used to convert an audio electrical signal into a sound signal. When the electronic device 1000 receives a call or a voice message, the voice can be received by placing the receiver 170B close to the human ear.

[0347] Microphone 170C, also called "microphone" or "microphone", is used to convert sound signals into electrical signals. When making a call or sending a voice message, the user can speak by putting their mouth close to microphone 170C to input the sound signal into microphone 170C. The electronic device 1000 can be provided with at least one microphone 170C. In other embodiments, the electronic device 1000 can be provided with two microphones 170C, which can not only collect sound signals but also realize noise reduction function. In other embodiments, the electronic device 1000 can also be provided with three, four or more microphones 170C to collect sound signals, reduce noise, identify the source of sound, realize directional recording function, etc.

[0348] The earphone interface 170D is used to connect a wired earphone and can be a USB interface, or a 3.5 mm open mobile terminal platform (OMTP) standard interface, or a cellular telecommunications industry association of the USA (CTIA) standard interface.

[0349] It should be noted that the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the electronic device 1000. In other embodiments of the present application, the electronic device 1000 may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0350] It can be understood that the method for call connection in the embodiment of the present application can be applied to Figure 8 In the electronic device shown in , the specific implementation steps can refer to the introduction of the method embodiment above, which will not be repeated here.

[0351] In addition, an operating system runs on the above components, such as an iOS operating system, an Android operating system, a Windows operating system, etc. Application programs can be installed and run on the operating system.

[0352] Exemplarily, the software architecture of the terminal device is described. The terminal device may be Figure 8 The software system of the electronic device 1000 shown in the figure can adopt a layered architecture, an event-driven architecture, a micro-core architecture, a micro-service architecture, or a cloud architecture. The embodiment of the present application takes a software system of a layered architecture as an example to exemplify the software structure of the electronic device 1000. Fig. 9 This is a software architecture block diagram of a terminal device provided in an embodiment of the present application. Fig. 9 by Figure 8 The software architecture of the electronic device 1000 shown in FIG. 1 is used as an example for explanation. Fig. 9 It is a software structure block diagram of the electronic device according to an embodiment of the present application.

[0353] The layered architecture divides the software into several layers, each with clear roles and division of labor. The layers communicate with each other through software interfaces. In some embodiments, the Android system is divided into four layers, from top to bottom: the application layer, the application framework layer, the Android runtime and system library, and the kernel layer.

[0354] The application layer can include a series of application packages. Fig. 9 As shown, the application package may include applications such as camera, gallery, calendar, call, map, navigation, WLAN, Bluetooth, music, video, short message, etc.

[0355] The application framework layer provides application programming interface (API) and programming framework for the applications in the application layer. The application framework layer includes some predefined functions. Fig. 9 As shown, the application framework layer may include a window manager, a content provider, a phone manager, a resource manager, a notification manager, a view system, and the like.

[0356] The window manager is used to manage window programs. The window manager can obtain the display screen size, determine whether there is a status bar, lock the screen, capture the screen, etc.

[0357] Content providers are used to store and retrieve data and make it accessible to applications. The data may include videos, images, audio, calls made and received, browsing history and bookmarks, phone books, etc.

[0358] The phone manager is used to provide communication functions for electronic devices, such as the management of call status (including answering, hanging up, etc.).

[0359] The resource manager provides various resources for applications, such as localized strings, icons, images, layout files, video files, and so on.

[0360] The notification manager enables applications to display notification information in the status bar. It can be used to convey notification-type messages and can disappear automatically after a short stay without user interaction. For example, the notification manager is used to notify download completion, message reminders, etc. The notification manager can also be a notification that appears in the system top status bar in the form of a chart or scroll bar text, such as notifications of applications running in the background, or a notification that appears on the screen in the form of a dialog window. For example, a text message is displayed in the status bar, a prompt sound is emitted, an electronic device vibrates, an indicator light flashes, etc.

[0361] The view system includes visual controls, such as controls for displaying text, controls for displaying images, etc. The view system can be used to build applications. A display interface can be composed of one or more views. For example, a display interface including a text notification icon can include a view for displaying text and a view for displaying images.

[0362] The core library consists of two parts: one part is the function that needs to be called by the Java language, and the other part is the Android core library.

[0363] The application layer and the application framework layer run in a virtual machine. The virtual machine executes the Java files of the application layer and the application framework layer as binary files. The virtual machine is used to perform functions such as object life cycle management, stack management, thread management, security and exception management, and garbage collection.

[0364] The system library may include multiple functional modules, such as surface manager, media library, 3D graphics processing library (such as OpenGL ES), 2D graphics engine (such as SGL), etc.

[0365] The surface manager is used to manage the display subsystem and provide the fusion of 2D and 3D layers for multiple applications.

[0366] The media library supports playback and recording of a variety of commonly used audio and video formats, as well as static image files, etc. The media library can support a variety of audio and video encoding formats, such as: MPEG2, H.262, MP3, AAC, AMR, JPG, PNG, etc.

[0367] The 3D graphics processing library is used to implement 3D graphics drawing, image rendering, synthesis and layer processing.

[0368] A 2D graphics engine is a drawing engine for 2D drawings.

[0369] The kernel layer is the layer between hardware and software. The kernel layer contains at least display driver, camera driver, audio driver, sensor driver, etc.

[0370] It should be noted that although the embodiments of the present application are described using the Android system as an example, its basic principles are also applicable to electronic devices based on operating systems such as iOS and Windows.

[0371] According to the method provided in the embodiment of the present application, the present application also provides a communication system, which includes the aforementioned first terminal, second terminal, called core network device, calling core network device, and ring back tone server. Optionally, it may also include calling access network device and called access network device.

[0372] The embodiment of the present application provides a chip system, which includes one or more processors for calling and running instructions stored in the memory from the memory, so that the method of the embodiment of the present application is executed. The chip system can be composed of chips, or it can include chips and other discrete devices.

[0373] Among them, the chip system may include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.

[0374] The present application also provides a computer program product, which, when executed by a processor, implements the method described in any method embodiment of the present application.

[0375] The computer program product can be stored in a memory, and is finally converted into an executable target file that can be executed by a processor after preprocessing, compiling, assembling and linking.

[0376] The present application also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a computer, the method described in any method embodiment of the present application is implemented. The computer program can be a high-level language program or an executable target program.

[0377] The computer-readable storage medium may be a volatile memory or a nonvolatile memory, or may include both a volatile memory and a nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DR RAM).

[0378] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described devices and equipment and the technical effects produced can refer to the corresponding processes and technical effects in the aforementioned method embodiments, and will not be repeated here.

[0379] In several embodiments provided in the present application, the disclosed systems, devices and methods can be implemented in other ways. For example, some features of the method embodiments described above can be ignored or not performed. The device embodiments described above are merely schematic, and the division of units is only a logical function division. There may be other division methods in actual implementation, and multiple units or components may be combined or integrated into another system. In addition, the coupling between the units or the coupling between the components may be direct coupling or indirect coupling, and the above coupling includes electrical, mechanical or other forms of connection.

[0380] It should be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0381] In addition, the terms "system" and "network" are often used interchangeably in this article. The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0382] The terms (or numbers) "first", "second", ..., etc. that appear in the embodiments of the present application are only used for descriptive purposes, that is, only to distinguish different objects, such as different "signalings", etc., and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", ..., etc. may explicitly or implicitly include one or more features. In the description of the embodiments of the present application, "at least one (item)" refers to one or more. "Multiple" means two or more. "At least one of the following (item)" or similar expressions thereof refers to any combination of these items, including any combination of a single (item) or a plurality of (items).

[0383] In short, the above is only a preferred embodiment of the technical solution of this application, and is not intended to limit the protection scope of this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application should be included in the protection scope of this application.

Claims

1. A method for call connection, characterized in that: The method is applied to a first terminal, the first terminal subscribes to a color ring back tone service, and the method includes: When the second terminal initiates a first call to the first terminal, receiving a first INVITE signaling from the second terminal; After detecting the user's answering action, sending a first 200OK signaling in response to the first INVITE signaling; Based on the first call, receiving a second INVITE signaling, the second INVITE signaling includes a first identifier, the first INVITE signaling does not include the first identifier, and the first terminal does not receive a first ACK signaling after sending the first 200OK signaling and before receiving the second INVITE signaling; In response to the second INVITE signaling, a second 200OK signaling is sent.

2. The method according to claim 1, characterized in that After receiving the second INVITE signaling, the method further includes: Determining whether the first ACK signaling is received; The sending of the second 200OK signaling includes: When the first ACK signaling is not received, the second 200OK signaling is sent.

3. The method according to claim 2, characterized in that The method further comprises: Determining whether the first timer has timed out; The sending of the second 200OK signaling includes: If the first ACK signaling is not received and the first timer has not timed out, the second 200OK signaling is sent. The first timer has not timed out, which means that the timing duration of the first timer is less than or equal to the preset duration. The timing duration of the first timer refers to the time between the moment when the user's answering action is detected and the current moment, or the time between the moment when the first 200OK signaling is sent and the current moment.

4. The method according to claim 3, characterized in that The method further comprises: If the first ACK signaling is not received and the first timer times out, a 491 signaling is sent.

5. The method according to any one of claims 1 to 4, characterized in that The method further comprises: receiving a second ACK signaling from the second terminal; After receiving the second ACK signaling, receive voice data from the second terminal, or send voice data to the second terminal.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: After receiving the first INVITE signaling, a 180 Ringing signaling is sent to the second terminal.

7. The method according to claim 6, characterized in that Before sending the 180Ringing signaling, the method further includes: receiving an UPDATE signaling from the second terminal; In response to the UPDATE signaling, a third 200OK signaling is sent.

8. The method according to any one of claims 1 to 7, characterized in that The first 200OK signaling is sent after the playing of the color ring tone starts; the second INVITE signaling is received after the playing of the color ring tone stops.

9. An electronic device, characterized in that: The electronic device comprises a processor and a memory, wherein the processor and the memory are coupled, and the memory is used to store a computer program. When the computer program is executed by the processor, the electronic device executes the method according to any one of claims 1 to 8.

10. A chip, characterized in that: The method comprises a processor, and when the processor executes instructions, the processor performs the method according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer-executable program, and when the computer-executable program is called by a computer, the computer executes the method according to any one of claims 1 to 8.

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