CN114268609A

CN114268609A - Voice service switching method, terminal equipment and chip

Info

Publication number: CN114268609A
Application number: CN202010975524.8A
Authority: CN
Inventors: 沈玉娟
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2022-04-01
Anticipated expiration: 2040-09-16
Also published as: WO2022057473A1; CN114268609B

Abstract

The embodiment of the application provides a voice service switching method, terminal equipment and a chip. The method comprises the following steps: the terminal equipment uses a first network to carry out IMS registration and starts an IMS timer; if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request and starting a first timer to time; and if the PDU session is established but the IMS registration is not completed within the timing duration of the IMS timer, determining a second retry time of the IMS registration request and starting a second timer to time. And forbidding the first network within the retry time and switching to use the second network to establish the IMS voice service or the Circuit Switched Fallback (CSFB) voice service, stopping using the second network when the timing duration of the timer reaches the retry time, and switching to use the first network to establish the IMS voice service. The embodiment of the application can enable the terminal to use the 5G network to the maximum extent and prevent the terminal from ping-pong between the 5G network and the 4G network.

Description

Voice service switching method, terminal equipment and chip

Technical Field

The present application relates to the field of mobile communication technologies, and in particular, to a voice service switching method, a terminal device, and a chip.

Background

5G (nr) is a fifth generation mobile communication network, which is a new mobile communication technology and can provide access with large bandwidth, full connection and low delay compared with 2/3/4G technology. An Internet Protocol (IP) multimedia subsystem (IMS) is a network system for providing multimedia services based on an IP network, and can provide voice solutions for 4G networks and 5G networks through the IMS.

Generally, in a case where a 4G network supports Circuit Switch Fallback (CSFB), before IMS registration is successful, voice communication may fall back to 2/3G network through the 4G network, so that voice communication may be guaranteed through a CS domain, and a terminal device may reside in Long Term Evolution (LTE) for a Long time.

However, voice communication in the 5G network can only be performed through the IMS domain, and voice communication cannot be guaranteed until IMS registration is successful, and at this time, the terminal device cannot reside in the 5G network for a long time. Specifically, if the IMS cannot provide services normally, the terminal device disables the 5G network for a fixed time, switches to another network, such as a 4G network, disables the network after timeout, and re-searches for the 5G access network. The terminal device does not consider abnormal conditions of different stages, such as abnormal IMS PDU session establishment or retry time of different stages corresponding to abnormal IMS network registration, namely, the terminal device disables the 5G network for the same fixed time no matter which stage is abnormal during IMS registration, which is not beneficial to ensuring that the terminal device uses the 5G network to the maximum extent and preventing the terminal device from generating ping-pong phenomenon between the 5G network and the 4G network, thereby affecting the service experience effect.

Disclosure of Invention

The embodiment of the application provides a voice service switching method, terminal equipment and a chip, which can enable the terminal equipment to use a 5G network to the maximum extent and prevent the terminal equipment from ping-pong between the 5G network and a 4G network.

In a first aspect, an embodiment of the present application provides a voice service switching method, where the voice service switching method includes: the method comprises the steps that terminal equipment uses a first network to conduct IMS registration and starts an IMS timer, wherein the IMS registration comprises PDU session establishment and IMS network registration, and the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and complete the IMS network registration; if the terminal equipment does not establish the PDU session within the timing duration of the IMS timer, the terminal equipment determines the first retry time of the PDU session establishment request and starts a first timer to time; the terminal equipment forbids the first network within the first retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; when the timing duration of the first timer reaches a first retry time, the terminal equipment stops using the second network and switches to use the first network to establish an IMS voice service; if the terminal equipment establishes the PDU session within the timing duration of the IMS timer but does not finish IMS network registration, the terminal equipment determines the second retry time of the IMS network registration request and starts a second timer for timing; the terminal equipment forbids the first network within the second retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the second timer reaches the second retry time, the terminal equipment stops using the second network and switches to use the first network to establish the IMS voice service.

The voice service switching method according to the embodiment of the present application can determine retry time, i.e., the first retry time or the second retry time, of different stages according to abnormal conditions of PDU session establishment or IMS network registration in different stages, disable the 5G network within the retry time, establish an IMS voice service through the 4G network or fall back to the 2/3G network for a CS voice service, and retry to establish the IMS voice service using the 5G network after the retry time is reached, so that the terminal device can maximally use the 5G network and prevent the terminal device from ping-pong between the 5G network and the 4G network, and can more accurately control the use of the 5G network, thereby ensuring the continuity of the voice service and achieving better service experience.

In a second aspect, an embodiment of the present application provides a voice service switching method, where the voice service switching method includes: the terminal equipment sends a PDU session establishment request to a core network of a first network; if the terminal equipment does not establish the PDU session within the timing duration of the IMS timer, the terminal equipment determines the first retry time of the PDU session establishment request and starts the first timer to time, wherein the timing duration of the IMS timer is the longest time required for stipulating that the terminal equipment establishes the PDU session and completes IMS network registration; the terminal equipment forbids the first network within the first retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the first timer reaches the first retry time, the terminal equipment stops using the second network and switches to use the first network to establish the IMS voice service.

The voice service switching method according to the embodiment of the present application can determine the first retry time according to the abnormal condition of PDU session establishment, disable the 5G network within the first retry time, establish the IMS voice service through the 4G network or fall back to the 2/3G network for the CS voice service, and retry to establish the IMS voice service using the 5G network when the first retry time is reached, so that the terminal device can use the 5G network to the maximum extent and prevent the terminal device from ping-pong between the 5G network and the 4G network, and can more accurately control the use of the 5G network, thereby ensuring the continuity of the voice service and achieving better service experience.

In a possible implementation manner, when the terminal device receives an error code cause value of PDU session establishment exception sent by a core network of the first network but not an error code cause value permanently forbidden by an operator, the terminal device determines a first retry time of the PDU session establishment request, including: if the error code cause value abnormal in PDU session establishment carries delay time, the terminal equipment determines the delay time as the first retry time; or, if the error code cause value abnormal in PDU session establishment is not carried or is carried as 0, the terminal device determines that the fixed time is the first retry time.

In a possible implementation manner, when the terminal device continuously receives the same error code cause value which is abnormal for the PDU session establishment, the terminal device determines, as the first retry time, a time obtained by accumulating a certain penalty time according to a delay time or a fixed time obtained according to the error code cause value which is abnormal for the PDU session establishment, wherein the penalty time accumulated each time is the same or different until the maximum penalty time is accumulated, and then determines the delay time or the fixed time again as the first retry time.

In a possible implementation manner, when the terminal device receives an error code cause value sent by a core network of the first network and the error code cause value sent by the core network of the first network is abnormal for PDU session establishment and is a permanently forbidden error code cause value for an operator, the terminal device disables the first network until the terminal device is turned on or off or a card is plugged in or out or a flight is switched on or off or an IMS related switch is switched on or off.

In one possible implementation, when a third timer expires, where a timing duration of the third timer is a maximum time required for the terminal device to complete the PDU session establishment, the terminal device determines a first retry time of the PDU session establishment request, including: determining a time to retry the PDU session establishment request when the third timer expires, as the first retry time, is specified in a related standard protocol.

In a possible implementation manner, when the terminal device continuously generates the third timer timeout, the terminal device determines, as the first retry time, a time obtained by accumulating the time for retrying the PDU session establishment request according to the third timer timeout by a penalty time, where the accumulated penalty times are the same or different for each time until the maximum penalty time is reached, and then determines, as the first retry time, a time obtained by retrying the PDU session establishment request according to a relevant standard protocol when the third timer timeout again.

In one possible embodiment, the first network is a 5G network and the second network is a 4G network.

In a third aspect, an embodiment of the present application provides a voice service switching method, where the voice service switching method includes: after a terminal device establishes a PDU session with a core network of a first network, the terminal device sends an IMS network registration request to an IMS network; if the terminal equipment does not finish IMS network registration within the timing duration of the IMS timer, the terminal equipment determines a second retry time of the IMS network registration request and starts a second timer to time, wherein the timing duration of the IMS timer is the longest time required for setting up the PDU session and finishing the IMS network registration; the terminal equipment forbids the first network within the second retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the second timer reaches the second retry time, the terminal equipment stops using the second network and switches to use the first network to establish the IMS voice service.

The voice service switching method according to the embodiment of the present application can determine the second retry time according to the abnormal condition of IMS network registration, disable the 5G network within the second retry time, simultaneously establish the IMS voice service through the 4G network or fall back to the 2/3G network for the CS voice service, and retry to establish the IMS voice service using the 5G network when the second retry time is reached, so that the terminal device can use the 5G network to the maximum extent and prevent the terminal device from ping-pong between the 5G network and the 4G network, the use of the 5G network can be controlled more accurately, the continuity of the voice service is ensured, and the service experience is better.

In a possible implementation manner, when the terminal device receives an error code cause value of an IMS network registration anomaly sent by a core network of the first network, the determining, by the terminal device, a second retry time of the IMS network registration request by the terminal device includes: if the error code cause value abnormal in IMS network registration carries retry duration, the terminal device determines the retry duration as the second retry time; or, if the error code cause value of the IMS network registration abnormality is not carried, the terminal device determines a retry duration of the IMS network registration request corresponding to the error code cause value of the IMS network registration abnormality specified in the relevant standard protocol as the second retry time.

In a possible implementation manner, when the terminal device continuously receives the same error code cause value of the IMS network registration abnormality, the terminal device determines, as the second retry time, a time obtained by accumulating a retry time obtained according to the error code cause value of the IMS network registration abnormality for a penalty time, where the penalty time accumulated each time is the same or different until a maximum penalty time is accumulated, and then determines the retry time again as the second retry time.

In a possible implementation manner, when the terminal device receives an error code cause value of IMS network registration abnormality sent by a core network of the first network and the error code cause value of IMS network registration abnormality is an error code cause value that an operator is permanently prohibited from entering, the terminal device disables the first network until the terminal device is turned on or off, or a card is plugged in or out, or a flight is switched on or off, or an IMS related switch is switched on or off.

In one possible implementation, when a fourth timer expires, where a timing duration of the fourth timer is a maximum time required for the terminal device to complete the IMS network registration, the determining, by the terminal device, a second retry time of the IMS network registration request by the terminal device includes: determining a time for retrying the IMS network registration request when the fourth timer expires, as the second retrying time, specified in a relevant standard protocol.

In a possible implementation manner, when the terminal device continuously generates the fourth timer timeout, the terminal device determines, as the second retry time, a time obtained by accumulating the time for retrying the IMS network registration request according to the fourth timer timeout for a penalty time, where the accumulated penalty times are the same or different for each time until the time is accumulated to a maximum penalty time, and then determines, as the second retry time, a time obtained by retrying the IMS network registration request according to a relevant standard protocol when the fourth timer timeout occurs again.

In a fourth aspect, an embodiment of the present application provides a terminal device, including a memory and a processor, where the memory is used for storing a computer program; the processor is configured to execute the computer program stored in the memory to perform: using a first network to perform IMS registration and starting an IMS timer, wherein the IMS registration comprises PDU session establishment and IMS network registration, and the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and complete the IMS network registration; if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request and starting a first timer to time; forbidding the first network within the first retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; when the timing duration of the first timer reaches the first retry time, stopping using the second network, and switching to using the first network to establish an IMS voice service; if the PDU session is established but the IMS network registration is not completed within the timing duration of the IMS timer, determining a second retry time of an IMS network registration request and starting a second timer to time; forbidding the first network within the second retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the second timer reaches the second retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

In a fifth aspect, an embodiment of the present application provides a terminal device, including a memory and a processor, where the memory is used for storing a computer program; the processor is configured to execute the computer program stored in the memory to perform: sending a PDU session establishment request to a core network of a first network; if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request and starting the first timer to time, wherein the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and finish IMS network registration; forbidding the first network within the first retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the first timer reaches the first retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

In a sixth aspect, an embodiment of the present application provides a terminal device, including a memory and a processor, where the memory is used for storing a computer program; the processor is configured to execute the computer program stored in the memory to perform: after a PDU session is established with a core network of a first network, an IMS network registration request is sent to an IMS network; if the IMS network registration is not completed within the timing duration of the IMS timer, determining a second retry time of the IMS network registration request and starting a second timer to time, wherein the timing duration of the IMS timer is the longest time required for setting up the PDU session and completing the IMS network registration; forbidding the first network within the second retry time, and establishing an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the second timer reaches the second retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

In a seventh aspect, an embodiment of the present application provides a chip, configured to implement the function of the terminal device.

In an eighth aspect, an embodiment of the present application provides a computer-readable storage medium for storing a computer program, which, when executed by a processor of a terminal device, causes the terminal device to implement the above-mentioned voice service switching method.

In a ninth aspect, an embodiment of the present application provides a computer program product, where the computer program product includes a computer program/instruction, and when the computer program/instruction runs on a terminal device, the terminal device is caused to implement the above-mentioned voice service switching method.

In the process of establishing the IMS service in the 5G network, the terminal device may determine retry times of different phases corresponding to different phases, for example, PDU session establishment or IMS registration is abnormal, and disable the 5G network within the retry time, and switch to use the 4G network to establish the voice service at the same time, stop using the 4G network when the retry time reaches, and switch to use the 5G network to establish the IMS voice service, thereby ensuring that the terminal device can use the 5G network to the maximum extent, preventing the terminal device from being between the 5G network and the 4G network, and controlling the use of the 5G network more accurately, avoiding the situation that the voice service cannot be performed normally, ensuring continuity of the voice service, and achieving better service experience.

Drawings

Fig. 1 is a schematic diagram of a network architecture to which the present invention is applied;

fig. 2 is a flow chart of IMS registration under the network architecture of fig. 1;

fig. 3 is a detailed flowchart of IMS registration in a 5G network;

fig. 4 is a flowchart of a voice service switching method applied to the network architecture of fig. 1;

fig. 5 is a flowchart of a voice service switching method in a first scenario according to a first embodiment of the present application; .

Fig. 6 is a flowchart of a voice service switching method in a second scenario according to a first embodiment of the present application;

fig. 7 is a flowchart of a voice service switching method in a third scenario according to the first embodiment of the present application;

fig. 8 is a flowchart of a voice service switching method in a first scenario according to a second embodiment of the present application;

fig. 9 is a flowchart of a voice service switching method in a second scenario according to a second embodiment of the present application;

fig. 10 is a flowchart of a voice service switching method in a third scenario according to a second embodiment of the present application;

fig. 11 is a schematic structural diagram of a terminal device according to an embodiment of the present application.

Detailed Description

The technical solution in the embodiments of the present invention will be described below with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present disclosure, and not all embodiments.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the specification. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise.

Wherein in the description of the present specification, "/" indicates a meaning, for example, a/B may indicate a or B; "and/or" herein is merely an association describing an associated object, and means that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality" means two or more than two.

In the description of the present specification, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.

Fig. 1 is a schematic diagram of a network architecture to which the embodiment of the present invention is applied. As shown in fig. 1, the network architecture includes a terminal device 101, an access network device 102 providing an 2/3G network for the terminal device 101, an access network device 103 providing an LTE network for the terminal device 101, an access network device 104 providing an NR network for the terminal device 101, a core network device 105, and an IP Multimedia Subsystem (IMS) 106.

Terminal equipment 101, also referred to as User Equipment (UE), may be deployed on land, including indoors or outdoors, hand-held, or vehicle-mounted; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, balloons, satellites, etc.). The terminal device may be a mobile phone (mobile phone), a tablet computer (pad), a computer with a wireless transceiving function, a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless device in industrial control (industrial control), a wireless device in self driving (self driving), a wireless device in remote medical (remote medical), a wireless device in smart grid (smart grid), a wireless device in transportation safety (transportation safety), a wireless device in smart city (smart city), a wireless device in smart home (smart home), and the like. The terminal device 101 is configured to generate a registration request, send the generated registration request to a P-CSCF entity in the IMS 106 through the access network and the core network, and receive a registration response message returned from the IMS 106 through the core network and the access network.

The core network device 105 may include a 5G core (5G core, 5GC) device, an Evolved Packet Core (EPC) device, and an 2/3G core network device. The device in the 5GC includes an access and mobility management function device (AMF) that performs access and mobility management on the terminal device, a session management function device (SMF) that manages a session of the terminal device, and a user plane function device (UPF) that controls a user plane of the terminal device. Of course, the core network device may also include other devices, for example, a device performing a policy control function. Devices in the EPC may include a Mobility Management Entity (MME), a Packet Gateway (PGW) that manages movement of the terminal device.

The IP Multimedia Subsystem (IMS)106 may include a proxy call state control function, P-CSCF, entity, an interrogating-call state control function (I-CSCF), a serving-call state control function (S-CSCF), entity, and a Home Subscriber Server (HSS). The P-CSCF entity is the first point of attachment of the access network to the IMS, and all session messages originating from and terminating at the IMS-capable terminal device are forwarded through the P-CSCF entity. The P-CSCF entity is operable to forward the registration request from the terminal device to the S-CSCF entity and to forward the registration reply information to the terminal device. The I-CSCF entity may connect the S-CSCF entity and the P-CSCF entity for providing the terminal device with access to the home network. In the IMS registration process, the P-CSCF entity may forward the registration request message from the terminal device to the I-CSCF entity, and the I-CSCF entity may query the HSS in the IMS to select an S-CSCF entity for the terminal device. In the calling process, a calling message destined for an IMS network is firstly routed to an I-CSCF, an I-CSCF entity can inquire the address information of an S-CSCF entity registered by a user for terminal equipment through an HSS in the IMS, and then the message is routed to the S-CSCF. The S-CSCF entity is the control core of the IMS and provides functions of session control, registration and the like for the terminal equipment. The S-CSCF entity is used for receiving the registration request of the terminal equipment forwarded by the P-CSCF entity and is matched with the HSS to authenticate the terminal equipment; and acquiring the subscription information of the terminal equipment from the HSS after the authentication is determined to pass. And the S-CSCF entity is also used for connecting with each application server based on the ISC interface, and triggering the application servers to execute operation, and routing the request message of the terminal equipment to the corresponding application servers. The HSS is the main data store in the IMS that stores all user and service related data. The data stored in the HSS mainly includes user identity, subscription information, access information, and the like.

Fig. 2 is a flow chart of IMS registration under the network architecture of fig. 1. As shown in fig. 2, IMS registration includes PDU session establishment and IMS network registration. The IMS registration uses an IMS timer to time, the PDU session establishment uses a third timer to time, and the IMS network registration uses a fourth timer to time. Specifically, the IMS registration includes the following steps:

step 201, an IMS timer is started.

When the terminal equipment searches that the access network completes NAS registration and is attached to the network, the terminal equipment starts IMS registration, and at the moment, an IMS timer is started. The timing duration of the IMS timer may be a custom duration, for example, 35s, which is smaller than the default timer duration 128s specified in the protocol.

In step 202, a third timer is started.

When the IMS timer is started and the terminal device completes the corresponding operation of IMS registration, then a PDU session establishment request needs to be sent to the core network, and at this time, the third timer is started.

Step 203, the terminal device sends a PDU session establishment request (PDU session establishment request) to the core network through the access network device.

Step 204, the core network sends a PDU session setup response (PDU session assignment accept) to the terminal device through the access network device.

In step 205, the third timer stops counting.

And the third timer stops timing because the terminal equipment receives the PDU session establishment response sent by the core network.

In step 206, a fourth timer is started.

When the third timer stops counting, the terminal device needs to send an IMS network registration request to the IMS network, and the fourth timer is started at this time.

Step 207, the terminal device sends an IMS network registration request to the IMS network through the access network device.

Step 208, the IMS network sends an IMS network registration completion message to the terminal device through the access network device.

In step 209, the fourth timer stops counting.

Since the terminal device receives the IMS network registration completion message sent by the IMS network, the fourth timer stops timing.

In step 210, the IMS timer stops counting.

And after the fourth timer stops timing, the IMS timer stops timing after the terminal equipment performs corresponding operation according to the received IMS network registration completion message.

That is, step 203 and step 204 are PDU session establishment procedures, and the PDU session can be established by completing step 203 and step 204 within the timing duration of the third timer. Step 207 and step 208 are IMS network registration procedures, and the IMS network can be successfully registered after step 207 and step 208 are completed within the timing duration of the fourth timer. Accordingly, the IMS registration requires that step 201 and step 210 be completed within the timing duration of the IMS timer. Also, the IMS registration procedure may be performed in a 4G network or a 5G network.

Fig. 3 is a specific flowchart of IMS registration in a 5G network. As shown in fig. 3, the method comprises the following steps:

step 301, the registration control module in the terminal device sends a non-access stratum (NAS) registration request to a 5G non-access stratum (NR non-access stratum, NRNAS) module in the terminal device. Among them, the NRNAS module mainly contains mobility management and session management functions.

In step 302, the NRNAS module sends a NAS registration request to an access and mobility management function (AMF) entity.

Step 303, the processes of authentication, authorization and the like are performed between the AMF entity and the terminal device.

Step 304, the AMF entity sends a response message carrying NAS registration success to the NRNAS module.

Step 305, the NRNAS module sends a response message carrying successful NAS registration to the registration control module.

In step 306, the NRNAS module sends a NAS registration complete message to the AMF entity.

That is, after the terminal device searches for the 5G network, for example, an operation of turning on a 5G network switch or turning off a flight mode by a user is received, or the terminal device moves from a non-5G network coverage area to a 5G network coverage area, and performs NAS registration in the 5G network. Next, when the terminal device completes NAS registration and attaches to the 5G network, the terminal device starts an IMS registration procedure. Specifically, the IMS registration process mainly includes the following steps:

step 307, the registration control module starts an IMS timer. The timing duration of the IMS timer may be a custom duration, for example, 35s, which is smaller than the default timer duration 128s specified in the protocol.

Step 308, the registration control module sends an IMS registration request to the IMS module.

Wherein the IMS timer may be started while the registration control module sends the IMS registration request to the IMS module. I.e. step 307 and step 308 may be performed simultaneously.

In step 309, the IMS module in the terminal device sends an IMS Protocol Data Unit (PDU) connection establishment request to the NRNAS module.

In step 310, the NRNAS module sends a PDU session establishment request (PDU session establishment request) to the AMF entity.

In step 311, the AMF entity sends a PDU session setup response (PDU session assignment accept) to the NRNAS module.

In step 312, the NRNAS module sends an IMS PDU session setup response to the IMS module.

Step 313, the IMS module sends an IMS network registration request to the P-CSCF.

In step 314, the P-CSCF sends an IMS network registration complete message to the IMS module.

In step 315, the IMS module stops the IMS timer. Then, the terminal device can generate a voice service request message according to the user requirement and send the voice service request message to the P-CSCF of the IMS network to establish the voice service.

Under the condition that the 4G network supports Circuit Switched Fallback (CSFB), and before IMS registration is successful, voice communication can fall back to the 2/3G network through the 4G network, so that voice communication can be guaranteed through the CS domain, and the terminal device can reside in Long Term Evolution (LTE). Voice communication in the 5G network can only be performed through the IMS domain, and it is impossible to ensure voice communication before IMS registration is completed, and at this time, the terminal device cannot reside in the 5G network for a long time, and needs to search for other networks, such as a 4G network, to stay, and establish a voice service using the 4G network when necessary.

Fig. 4 is a flowchart of a voice service switching method applied to the network architecture in fig. 1. As shown in fig. 4, the voice service switching method may include the following steps:

step 401, the terminal device determines that the IMS service cannot be provided in the time duration of the IMS timer in the 5G network. Namely, an abnormality occurs at the time of IMS registration. For example, a PDU session setup exception or an IMS network registration exception.

And step 402, the terminal equipment starts a fifth timer, disables the 5G network for a fixed time, and simultaneously searches for the 4G network. Specifically, the terminal device searches for a 4G access network and performs an NAS registration process. When the terminal device completes NAS registration and is attached to the 4G network, IMS registration may be performed according to steps 201 to 210 shown in fig. 2 to establish a voice service, and if the terminal device cannot establish an IMS voice service in the 4G network, the terminal device may fall back to the 2/3G network to perform a CS voice service in a circuit switched domain when the voice service is required.

And step 403, if the fifth timer is overtime and the fixed time is reached, the terminal equipment stops using the 4G network and searches the 5G network again. That is, the 5G access network is searched again, and IMS registration is performed under the 5G network according to the steps shown in fig. 3, so as to establish a voice service.

In the above scheme, no matter which stage is abnormal when IMS registration is performed, the terminal device disables the 5G network for the same fixed time, for example, 5 minutes, and different stages, such as retry times of different stages corresponding to abnormal situations of PDU session establishment or IMS network registration, are not considered. If the retry time of the abnormal stage is less than the fixed time of forbidding the 5G network, the 5G network is searched again after the fixed time is reached, which is not beneficial to ensuring the maximum use of the 5G network; if the retry time of the abnormal stage is longer than the fixed time of disabling the 5G network, for example, the current cell cannot provide a normal IMS service, the terminal device may search the 5G access network again to perform IMS registration after the fixed time is reached, because the retry time corresponding to the abnormal stage, such as PDU session establishment or IMS network registration, has not yet arrived, the PDU session cannot be established and/or IMS network registration is completed at this time, the terminal device may disable the fixed time of the 5G network again and switch to the 4G network, so that the terminal device may ping-pong between the 5G network and the 4G network, that is, change back and forth, and cannot ensure the continuity of the service. Both the above two situations can affect the normal use of the 5G network, and the better service experience effect cannot be ensured.

In view of this, the embodiment of the present application provides a voice service switching method, which is applied to a system including a terminal device, a first network and a second network, wherein the first network may only support an IMS voice service, for example, a 5G network, and the second network may support an IMS voice service and a circuit domain fallback CSFB voice service, for example, a 4G network, the voice service switching method can determine retry times of different stages according to abnormal conditions of the different stages, such as PDU session establishment or IMS network registration, and disable the 5G network within the retry time, while establishing the IMS voice service through the 4G network or dropping to the 2/3G network for a CS voice service, and re-attempt to establish the IMS voice service using the 5G network after the retry times are reached, so that the terminal device can maximally use the 5G network and prevent the terminal device from ping-pong between the 5G network and the 4G network, the voice service can be normally carried out, and the service experience effect is good.

The following respectively introduces specific processes of the voice service switching method according to the embodiment of the present application when the PDU session establishment process and the IMS network registration process are abnormal. The PDU session establishment exception and the IMS network registration exception respectively comprise three scenes. Specifically, the first scenario is that the terminal device receives an error code cause value (a non-operator customized permanently prohibited error code cause value) sent by the network side within the timing duration of a corresponding timer; the second scenario is that the timer of the corresponding process is overtime (no error code cause value is received); and the third scenario is that the terminal equipment receives an operator-customized permanently forbidden error code cause value sent by the network side within the timing duration of the corresponding timer.

Fig. 5 is a flowchart of a voice service switching method in a first scenario according to a first embodiment of the present application. In the voice service switching method according to the first embodiment of the present application, for the case of PDU session establishment abnormality in the 5G network, as described above, the PDU session establishment process uses the third timer for timing, that is, the timing duration of the third timer is the maximum time required for the terminal device to complete the PDU session establishment. The first scenario is that the terminal equipment receives error code cause value of PDU session establishment exception but the permanently forbidden error code cause value is customized by non-operator. As shown in fig. 5, the voice service switching method includes the following steps:

step 501, the terminal device starts a third timer.

Step 502, the terminal device sends a PDU session establishment request to the 5G core network.

Step 503, the 5G core network sends the error code cause value of PDU session establishment exception to the terminal device. The error code cause value of the PDU session establishment exception may be specifically referred to in table 1 below.

In step 504, the third timer stops counting.

The third timer stops counting time because the terminal equipment receives the error code cause value of the PDU session establishment exception.

And 505, if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request according to an error code cause value of the PDU session establishment anomaly.

That is, when the error code cause value of PDU session establishment exception is received within the timing duration of the IMS timer, the terminal device will resend the PDU session establishment request according to the standard protocol. Then, when the PDU session is not established after the time length of the IMS timer reaches, the terminal device determines a first retry time of the PDU session establishment request according to the error code cause value of the received PDU session establishment exception. Specifically, if an error code cause value of the PDU session establishment anomaly carries a delay time back-off specified in a standard protocol, the terminal device determines that the first retry time is the delay time; and if the error code cause value abnormal in PDU session establishment does not carry or carries 0, the terminal equipment determines that a fixed time is a first retry time.

In addition, when the terminal device continuously receives the same error code cause value which is abnormal for the PDU session establishment, the terminal device may determine a first retry time by accumulating a delay time or a time obtained by accumulating a certain penalty time according to the error code cause value which is abnormal for the PDU session establishment, wherein the penalty time accumulated each time is the same or different until the maximum penalty time is accumulated, and then determine the delay time or the set time as the first retry time again.

Step 506, the terminal device starts a first timer, and the timing duration of the first timer is a first retry time.

Step 507, the terminal device disables the 5G network within the first retry time, and switches to establish the IMS voice service or the circuit switched fallback CSFB voice service using the 4G network. Specifically, the terminal device searches for the 4G access network, performs the NAS registration process, and when the terminal device completes the NAS registration and attaches to the 4G network, the terminal device may perform IMS registration according to steps 201 to 210 shown in fig. 2 to establish the voice service, and if the terminal device cannot establish the IMS voice service in the 4G network, the terminal device may fall back to the 2/3G network to perform the CS voice service in the circuit switched domain when the voice service needs to be performed.

In step 508, a first timer is timed out.

Step 509, the terminal device stops using the 4G network and switches to use the 5G network to establish the IMS voice service

Specifically, the terminal device searches for the 5G access network again, and performs NAS registration, PDU session establishment, and IMS network registration in the 5G network according to the steps shown in fig. 3, so as to establish the IMS voice service.

Fig. 6 is a flowchart of a voice service switching method provided in the first embodiment of the present application in a second scenario. The second scenario is that the third timer times out. At this time, as shown in fig. 6, the voice service switching method includes the following steps:

step 601, starting a third timer.

Step 602, the terminal device sends a PDU session establishment request to the 5G core network.

Step 603, the third timer times out. That is, the terminal device does not establish the PDU session, and does not receive the error code cause value sent by the 5G core network within the timing duration of the third timer.

Step 604, if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request according to the timeout of the third timer.

That is, when the third timer times out within the time duration of the IMS timer, the terminal device retransmits the PDU session establishment request according to the standard protocol. Then, when the PDU session is not established after the time length of the IMS timer reaches, the terminal device will timeout a third timer specified in the standard protocol 3GPP 24.501, and determine the time for retrying the PDU session establishment request as the first retrying time. In addition, when the terminal device continuously generates the time-out of the third timer, the terminal device determines the time obtained by accumulating the time of retrying the PDU session establishment request obtained by the time-out of the third timer for a penalty time as the first retry time, the accumulated penalty time is the same or different each time until the time is accumulated to the maximum penalty time, and then determines the time obtained by retrying the PDU session establishment request obtained by the standard protocol 3GPP 24.501 when the third timer is time-out as the first retry time again.

Step 605, the terminal device starts a first timer, and the timing duration of the first timer is a first retry time.

Step 606, forbidding the 5G network within the first retry time, and switching to establish the IMS voice service or the circuit switched fallback CSFB voice service using the 4G network. Specifically, the terminal device searches for the 4G access network, performs the NAS registration process, and when the terminal device completes the NAS registration and attaches to the 4G network, the terminal device may perform IMS registration according to steps 201 to 210 shown in fig. 2 to establish the voice service, and if the terminal device cannot establish the IMS voice service in the 4G network, the terminal device may fall back to the 2/3G network to perform the CS voice service in the circuit switched domain when the voice service needs to be performed.

In step 607, the first timer is up.

Step 608, the terminal device stops using the 4G network and switches to use the 5G network to establish the IMS voice service.

Specifically, the terminal device searches for the 5G access network again, and performs NAS registration, PDU session establishment, and IMS network registration procedures in the 5G network according to the steps shown in fig. 3, so as to establish the IMS voice service.

Fig. 7 is a flowchart of a voice service switching method in a third scenario according to the first embodiment of the present application. The third scenario is that when the terminal device establishes the PDU session, the operator customizes the permanently forbidden error code cause value. At this time, as shown in fig. 7, the voice service switching method includes the following steps:

step 701, a third timer is started.

In step 702, the terminal device sends a PDU session setup request to the 5G core network.

In step 703, the 5G core network sends the operator customized permanent forbidden error code cause value to the terminal device.

I.e. the terminal device cannot establish a PDU session without operator permission. And after operations such as payment or service activation are carried out, the operator is allowed to turn on or off the machine, or switch on or off the flight, or plug and unplug the card or switch on or off the related switch of the IMS.

In step 704, the third timer stops counting. The terminal equipment receives the error code reason value, so the third timer stops timing.

Step 705, if the PDU session is not established within the time length of the IMS timer, determining a first retry time of the PDU session establishment request according to the cause value of the permanently prohibited error code customized by the operator, where the first retry time is a time for recovering the use of the operator, that is, turning on or off the machine, or turning on or off the flight, or inserting or pulling out the card, or turning on or off the related switch of the IMS.

That is, when the operator-customized permanently disabled error code cause value is received within the timing duration of the IMS timer, the terminal device retransmits the PDU session establishment request according to the standard protocol. Then, when the PDU session is not established after the time length of the IMS timer reaches, the terminal device determines, according to the received operator-customized permanently prohibited error code cause value, the first retry time of the PDU session establishment request as the time for turning on or off the device, or turning on or off the flight, or inserting or pulling out the card, or turning on or off the IMS-related switch.

Step 706, the terminal device disables the 5G network until the 5G network is powered on or off, or the card is switched on or off or the IMS related switch is switched on or off, and establishes an IMS voice service or a circuit switched fallback CSFB voice service using the 4G network during the period of disabling the 5G network.

That is to say, the terminal device can resume searching for the 5G network after performing on-off, switching on a flight mode, or switching on and off a card or switching on and off an IMS related switch. Specifically, the terminal device searches for the 5G access network again, and performs NAS registration, PDU session establishment, and IMS network registration in the 5G network according to the steps shown in fig. 3, so as to establish the IMS voice service.

In order to more clearly understand the voice service switching method according to the first embodiment of the present application, different coping strategies for PDU session abnormality in a 5G network in the scheme before the improvement and the scheme after the improvement according to the first embodiment of the present application are compared, and specifically refer to table 1.

TABLE 1

That is to say, in the voice service switching method according to the first embodiment of the present application, when a PDU session is established abnormally, a terminal device may first determine a first retry time of a PDU session establishment request according to an abnormal condition in different scenarios, and then disable a 5G network (i.e., forbid searching for a 5G access network) and switch to establish an IMS voice service circuit domain fallback CSFB voice service using a 4G network within the first retry time, and stop using the 4G network and switch to establish the IMS voice service using the 5G network after the first retry time is reached, so that the terminal device can use the 5G network to the maximum extent, and can prevent the terminal device from ping-pong between the 5G network and the 4G network, so that the terminal more accurately controls the use of the 5G network, a situation that the service cannot be normally used is avoided, and service experience is better.

The foregoing describes a voice service switching method according to a first embodiment of the present application. A voice service switching method according to a second embodiment of the present application is described below, which is directed to a case where IMS network registration is abnormal. As described above, the IMS network registration is timed by using the fourth timer, that is, the timed duration of the fourth timer is the maximum time required for the terminal device to complete the IMS network registration.

Fig. 8 is a flowchart of a voice service switching method provided in a second embodiment of the present application in a first scenario. The first scenario is that the terminal device receives an error code cause value of IMS network registration anomaly and the error code cause value is not an operator customized permanently forbidden error code cause value. At this time, as shown in fig. 8, the voice service switching method includes the following steps:

in step 801, a fourth timer is started.

Step 802, the terminal device sends an IMS network registration request to the IMS network.

Step 803, IMS sends error code cause value of IMS network registration anomaly to the terminal device.

Wherein the error code cause value may be any one of 300-.

In step 804, the fourth timer stops counting.

The fourth timer stops timing because the terminal device receives the error code cause value of the IMS network registration anomaly.

Step 805, if the IMS network registration is not completed within the time length of the IMS timer, determining a second retry time of the IMS network registration request according to the error code cause value of the IMS network registration anomaly.

Namely, when the error code cause value of IMS network registration abnormity is received in the timing duration of the IMS timer, the terminal equipment resends the IMS network registration request according to the standard protocol. And then, when the IMS network registration is not finished after the timing duration of the IMS timer is up, the terminal equipment determines the second retry time of the IMS network registration request according to the received error code cause value of the IMS network registration abnormity. The second retry time is a time for retrying the IMS network registration request corresponding to the error code cause value of the IMS network registration anomaly specified in the standard protocol 3GPP24.229 or RFC 3261. When the error code cause value of IMS network registration abnormity carries retry time retry-after, determining retry-after as second retry time; when the error code cause value of the IMS network registration abnormality does not carry a retry after, the terminal device determines a retry time length, corresponding to the IMS network registration request, of the error code cause value of the IMS network registration abnormality specified in the corresponding standard protocol RFC 5626, as the second retry time.

When the terminal equipment continuously receives the same error code cause value which is abnormal in IMS network registration, the terminal equipment determines the time obtained by accumulating the retry time obtained according to the error code cause value which is abnormal in IMS network registration for a period of punishment time as second retry time, wherein the punishment time accumulated each time is the same or different until the time is accumulated to the maximum punishment time, and then determines the retry time as the second retry time again.

And 806, starting a second timer, wherein the timing duration of the second timer is a second retry time.

In step 807, the terminal device disables the 5G network within the second retry time, and switches to establish the IMS voice service or the circuit switched fallback CSFB voice service using the 4G network. Specifically, the terminal device searches for the 4G access network, performs the NAS registration process, and when the terminal device completes the NAS registration and attaches to the 4G network, the terminal device may perform IMS registration according to steps 201 to 210 shown in fig. 2 to establish the voice service, and if the terminal device cannot establish the IMS voice service in the 4G network, the terminal device may fall back to the 2/3G network to perform the CS voice service in the circuit switched domain when the voice service needs to be performed.

And 808, the second timer is timed to arrive.

Step 809, the terminal device stops using the 4G network and switches to use the 5G network to establish the IMS voice service.

Fig. 9 is a flowchart of a voice service switching method provided in a second embodiment of the present application in a second scenario. The second scenario is the fourth timer timeout. As shown in fig. 9, at this time, the voice service switching method includes the following steps:

in step 901, a fourth timer is started.

Step 902, the terminal device sends an IMS network registration request to the IMS network;

in step 903, the fourth timer times out.

Namely, the terminal device does not complete the IMS network registration and does not receive the error code cause value sent by the IMS network.

Step 904, if the IMS network registration is not completed within the time duration of the IMS timer, determining a second retry time of the IMS network registration request according to the timeout of the fourth timer.

That is, when the fourth timer times out within the time length of the IMS timer, the terminal device resends the IMS network registration request according to the standard protocol. Then, when the IMS network registration is not completed after the counted time of the IMS timer reaches, the terminal device will timeout a fourth timer defined in standard protocol RFC 5626, and determine the time for retrying the IMS network registration request as a second retry time. In addition, when the terminal device continuously generates the fourth timer timeout, the terminal device determines the time obtained by accumulating the time for retrying the IMS network registration request obtained according to the fourth timer timeout for a period of penalty time as the second retest time, the accumulated penalty time in each time is the same or different until the time is accumulated to the maximum penalty time, and then determines the time obtained by retrying the IMS network registration request according to the relevant standard protocol when the fourth timer timeout is over as the second retest time

Step 905, the terminal device starts a second timer, and the timing duration of the second timer is retry time.

Step 906, the terminal device disables the 5G network within the second retry time, and switches to establish the IMS voice service or the circuit switched fallback CSFB voice service using the 4G network. Specifically, the terminal device searches for the 4G access network, performs the NAS registration process, and when the terminal device completes the NAS registration and attaches to the 4G network, the terminal device may perform IMS registration according to steps 201 to 210 shown in fig. 2 to establish the voice service, and if the terminal device cannot establish the IMS voice service in the 4G network, the terminal device may fall back to the 2/3G network to perform the CS voice service in the circuit switched domain when the voice service needs to be performed.

In step 907, a second timer is timed out.

And 908, the terminal equipment stops using the 4G network and switches to use the 5G network to establish the IMS voice service.

Specifically, the terminal device searches for the 5G access network again, and performs NAS registration, PDU session establishment, and IMS registration processes in the 5G network according to the steps shown in fig. 3 to establish the IMS voice service.

Fig. 10 is a flowchart of a voice service switching method in a third scenario according to a second embodiment of the present application. The third scenario is that the operator customized permanent forbidden error code cause value is received in the process of carrying out IMS registration by the terminal equipment. At this time, as shown in fig. 9, the voice service switching method includes the following steps:

step 1001, a fourth timer is started.

In step 1002, the terminal device sends an IMS network registration request to the IMS network.

Step 1003, the IMS network sends the operator-customized permanently forbidden error code cause value to the terminal device.

That is, the terminal device cannot perform IMS network registration without obtaining operator permission. And after operations such as payment or service activation are carried out, the operator is allowed to turn on or off the machine, or switch on or off the flight, or plug and unplug the card or switch on or off the related switch of the IMS.

In step 1004, the fourth timer stops counting. Since the terminal device receives the operator-customized permanently disabled error code cause value sent by the IMS network, the fourth timer stops counting.

Step 1005, if the IMS network registration is not completed within the time length of the IMS timer, determining a second retry time according to the permanently prohibited error code cause value customized by the operator, where the retry time is a time for recovering the use of the operator, i.e., turning on or off the machine, or turning on or off the flight, or inserting or pulling out the card, or turning on or off the relevant switch of the IMS.

That is, when the operator-customized permanently-prohibited error code cause value with IMS network registration abnormality is received within the counting duration of the IMS timer, the terminal device retransmits the IMS network registration request according to the standard protocol. Then, when the IMS network registration is not completed after the time length of the IMS timer reaches, the terminal device determines a second retry time of the IMS network registration request according to the received operator-customized permanently prohibited error code cause value.

Step 1006, the terminal device disables the 5G network until the 5G network is powered on or off, or the card is switched on or off, or the IMS-related switch is switched on or off, and establishes an IMS voice service or a circuit switched fallback CSFB voice service using the 4G network during the period of disabling the 5G network.

Namely, the terminal equipment can restore and search the 5G network after being switched on and off, or switching on and off a flight mode, or plugging and unplugging a card or switching on and switching off related switches of the IMS. That is, the terminal device searches the 5G access network again, and performs NAS registration, PDU session establishment, and IMS network registration in the 5G network according to the steps shown in fig. 3 to establish the IMS voice service.

In order to more clearly understand the voice service switching method according to the second embodiment of the present application, a comparison is made between the scheme before the improvement and the scheme after the improvement according to the second embodiment of the present application, and specifically refer to table 2.

TABLE 2

That is to say, in the voice service switching method according to the second embodiment of the present application, when IMS network registration is abnormal, the terminal device may first determine a second retry time of the IMS network registration request according to an abnormal condition in different scenarios, then disable the 5G network (i.e. forbid searching the 5G access network) and switch to use the 4G network to establish the IMS voice service circuit domain fallback CSFB voice service within the second retry time, and when the second retry time is reached, stop using the 4G network and switch to use the 5G network to establish the IMS voice service, so that the terminal device can use the 5G network to the maximum extent, and can prevent the terminal device from ping-pong between the 5G network and the 4G network, so that the terminal more accurately controls the use of the 5G network, thereby avoiding a situation that the service cannot be normally used, and providing better service experience.

Based on the same concept as the method embodiment, the embodiment of the application further provides the terminal device. The terminal device is used for implementing each method step executed by the terminal device in the foregoing method embodiment. In other words, the specific working process of the terminal device may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.

Fig. 11 is a schematic structural diagram of a terminal device according to an embodiment of the present application. As shown in fig. 11, the terminal device 1100 may include a transceiver 1101, a memory 1102, and a processor 1103. The transceiver 1101 is configured to receive and transmit data, the memory 1102 is configured to store a computer program, and the processor 1103 can execute the computer program to implement the voice service switching method according to the embodiment of the present application.

Specifically, when the processor of the terminal device according to the first embodiment of the present application runs the computer program stored in the memory, the processor is at least configured to perform: using a first network to carry out IMS registration and starting an IMS timer, wherein the IMS registration comprises PDU session establishment and IMS network registration, and the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and finish the IMS network registration; if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request and starting a first timer to time; forbidding the first network within the first retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; when the timing duration of the first timer reaches the first retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service; if the PDU session is established but the IMS network registration is not completed within the timing duration of the IMS timer, determining a second retry time of the IMS network registration request and starting a second timer to time; forbidding the first network within the second retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using the second network; and when the timing duration of the second timer reaches the second retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

When the processor of the terminal device according to the second embodiment of the present application runs the computer program stored in the memory, the processor is at least configured to execute: sending a PDU session establishment request to a core network of a first network; if the PDU session is not established in the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request and starting the first timer to time, wherein the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and complete IMS network registration; forbidding the first network within the first retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the first timer reaches the first retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

When the processor of the terminal device according to the third embodiment of the present application runs the computer program stored in the memory, the processor is at least configured to execute: after a PDU session is established with a core network of a first network, an IMS network registration request is sent to an IMS network; if the IMS network registration is not completed within the timing duration of the IMS timer, determining a second retry time of an IMS network registration request and starting a second timer to time, wherein the timing duration of the IMS timer is the longest time required for setting up a PDU session and completing the IMS network registration; forbidding the first network within the second retry time, and establishing an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using the second network; and when the timing duration of the second timer reaches the second retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

The embodiment of the application also provides a chip/system on chip, and the chip/system on chip is used for realizing the method steps executed by the terminal equipment in the method embodiment of the application. Wherein the chip/system on a chip is deployed in a terminal device.

To sum up, in the process of establishing the IMS voice service in the 5G network, the terminal device may determine retry times of different phases corresponding to different phases, for example, when a PDU session is established or IMS network is abnormally registered, and forbid the 5G network within the retry time, and simultaneously switch to use the 4G network to establish the voice service, stop using the 4G network when the retry time reaches, and switch to use the 5G network to establish the IMS voice service, thereby ensuring that the terminal device can maximally use the 5G network, preventing the terminal device from ping-pong between the 5G network and the 4G network, and being capable of more accurately controlling the use of the 5G network, avoiding the situation that the service cannot be normally performed, ensuring the continuity of the voice service, and providing better service experience.

It is understood that the processor in the embodiments of the present application may be a Central Processing Unit (CPU), other general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The general purpose processor may be a microprocessor, but may be any conventional processor.

The method steps in the embodiments of the present application may be implemented by hardware, or may be implemented by software instructions executed by a processor. The software instructions may consist of corresponding software modules that may be stored in Random Access Memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), registers, a hard disk, a removable hard disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an ASIC.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the application to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in or transmitted over a computer-readable storage medium. The computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

It is to be understood that the various numerical references referred to in the embodiments of the present application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of the present application.

Claims

1. A voice service switching method is characterized in that the voice service switching method comprises the following steps:

the method comprises the steps that terminal equipment uses a first network to conduct IMS registration and starts an IMS timer, wherein the IMS registration comprises PDU session establishment and IMS network registration, and the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and complete the IMS network registration;

if the terminal equipment does not establish the PDU session within the timing duration of the IMS timer, the terminal equipment determines the first retry time of the PDU session establishment request and starts a first timer to time; the terminal equipment forbids the first network within the first retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; when the timing duration of the first timer reaches a first retry time, the terminal equipment stops using the second network and switches to use the first network to establish an IMS voice service;

if the terminal equipment establishes the PDU session within the timing duration of the IMS timer but does not finish IMS network registration, the terminal equipment determines the second retry time of the IMS registration request and starts a second timer to time; the terminal equipment forbids the first network within the second retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the second timer reaches the second retry time, the terminal equipment stops using the second network and switches to use the first network to establish the IMS voice service.

2. A voice service switching method is characterized in that the voice service switching method comprises the following steps:

the terminal equipment sends a PDU session establishment request to a core network of a first network;

if the terminal equipment does not establish the PDU session within the timing duration of the IMS timer, the terminal equipment determines the first retry time of the PDU session establishment request and starts the first timer to time, wherein the timing duration of the IMS timer is the longest time required for stipulating that the terminal equipment establishes the PDU session and completes IMS network registration;

the terminal equipment forbids the first network within the first retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network;

and when the timing duration of the first timer reaches the first retry time, the terminal equipment stops using the second network and switches to use the first network to establish the IMS voice service.

3. The voice service switching method according to claim 2, wherein when the terminal device receives an error code cause value of PDU session setup exception sent by a core network of the first network but not an error code cause value of operator permanent forbidden, the terminal device determines the first retry time of the PDU session setup request, and the method comprises:

if the error code cause value abnormal in PDU session establishment carries delay time, the terminal equipment determines the delay time as the first retry time; or the like, or, alternatively,

and if the error code cause value abnormal in PDU session establishment is not carried or is carried as 0, the terminal equipment determines that the fixed time is the first retry time.

4. The voice service switching method according to claim 3, wherein when the terminal device continuously receives the same error code cause value which is abnormal for the PDU session establishment, the terminal device determines, as the first retry time, a delay time obtained according to the error code cause value which is abnormal for the PDU session establishment or a time obtained by accumulating a certain penalty time for a fixed time, wherein the penalty time accumulated each time is the same or different until a maximum penalty time is accumulated, and then determines the delay time or the fixed time again as the first retry time.

5. The method according to claim 2, wherein when the terminal device receives an error code cause value sent by a core network of the first network and indicating that the PDU session establishment is abnormal, and the error code cause value indicates that an operator is permanently prohibited, the terminal device disables the first network until the terminal device is powered on or powered off, or a card is plugged in or out, or a switch flies, or an IMS related switch is switched on or off.

6. The voice service switching method according to claim 2, wherein when a third timer expires, wherein a timing duration of the third timer is a maximum time required for the terminal device to complete the PDU session establishment, the terminal device determines a first retry time of the PDU session establishment request, comprising:

determining a time to retry the PDU session establishment request when the third timer expires, as the first retry time, is specified in a related standard protocol.

7. The voice service switching method according to claim 6, wherein when the terminal device continuously generates the third timer timeout, the terminal device determines, as the first retry time, a time obtained by accumulating a time for retrying the PDU session establishment request according to the third timer timeout by a penalty time, the accumulated penalty time is the same or different for each time until a maximum penalty time is reached, and then determines, as the first retry time, a time obtained by retrying the PDU session establishment request according to a relevant standard protocol when the third timer timeout.

8. The voice service switching method according to any one of claims 1 to 7, wherein the first network is a 5G network and the second network is a 4G network.

9. A voice service switching method is characterized in that the voice service switching method comprises the following steps:

after a terminal device establishes a PDU session with a core network of a first network, the terminal device sends an IMS network registration request to an IMS network;

if the terminal equipment does not finish IMS network registration within the timing duration of the IMS timer, the terminal equipment determines a second retry time of the IMS registration request and starts a second timer to time, wherein the timing duration of the IMS timer is the longest time required for setting up the PDU session and finishing the IMS network registration;

the terminal equipment forbids the first network within the second retry time and switches to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network;

and when the timing duration of the second timer reaches the second retry time, the terminal equipment stops using the second network and switches to use the first network to establish the IMS voice service.

10. The method according to claim 9, wherein when the terminal device receives an error code cause value of IMS network registration anomaly sent by a core network of the first network, the terminal device determines the second retry time of the IMS network registration request, which includes:

if the error code cause value abnormal in IMS network registration carries retry duration, the terminal device determines the retry duration as the second retry time; or the like, or, alternatively,

and if the error code cause value of the IMS network registration abnormity is not carried, the terminal equipment determines the retry time length of the IMS network registration request corresponding to the error code cause value of the IMS network registration abnormity specified in the related standard protocol as the second retry time.

11. The voice service switching method according to claim 10, wherein when the terminal device continuously receives the same error code cause value of the IMS network registration anomaly, the terminal device determines, as the second retry time, a time obtained by accumulating a retry duration obtained according to the error code cause value of the IMS network registration anomaly for a penalty time, wherein the penalty times accumulated each time are the same or different until a maximum penalty time is accumulated, and then determines the retry duration again as the second retry time.

12. The method according to claim 9, wherein when the terminal device receives the error code cause value of the IMS network registration anomaly sent by the core network of the first network and the error code cause value of the IMS network registration anomaly is an error code cause value that is permanently prohibited by an operator, the terminal device disables the first network until powering on or powering off or plugging in a card or switching off and flight or switching on or off an IMS related switch.

13. The voice service switching method according to claim 9, wherein when a fourth timer expires, where a timing duration of the fourth timer is a maximum time required for the terminal device to complete the IMS network registration, the terminal device determines a second retry time of the IMS network registration request, and includes:

determining a time for retrying the IMS network registration request when the fourth timer expires, as the second retrying time, specified in a relevant standard protocol.

14. The voice service switching method according to claim 13, wherein when the terminal device continuously generates the fourth timer timeout, the terminal device determines, as the second retry time, a time obtained by accumulating the time for retrying the IMS network registration request according to the fourth timer timeout for a certain penalty time, the accumulated penalty time is the same or different for each time until the maximum penalty time is reached, and then determines, as the second retry time, a time for retrying the IMS network registration request again according to a relevant standard protocol when the fourth timer timeout is reached.

15. The voice service switching method according to any one of claims 9 to 14, wherein the first network is a 5G network and the second network is a 4G network.

16. A terminal device, comprising a memory and a processor,

the memory is used for storing a computer program;

the processor is configured to execute the computer program stored in the memory to perform:

using a first network to perform IMS registration and starting an IMS timer, wherein the IMS registration comprises PDU session establishment and IMS network registration, and the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and complete the IMS network registration;

if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request and starting a first timer to time; forbidding the first network within the first retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; when the timing duration of the first timer reaches the first retry time, stopping using the second network, and switching to using the first network to establish an IMS voice service;

if the PDU session is established but the IMS network registration is not completed within the timing duration of the IMS timer, determining a second retry time of an IMS network registration request and starting a second timer to time; forbidding the first network within the second retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network; and when the timing duration of the second timer reaches the second retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

17. A terminal device, comprising a memory and a processor,

the memory is used for storing a computer program;

sending a PDU session establishment request to a core network of a first network;

if the PDU session is not established within the timing duration of the IMS timer, determining a first retry time of the PDU session establishment request and starting the first timer to time, wherein the timing duration of the IMS timer is the longest time required for the terminal equipment to establish the PDU session and finish IMS network registration;

forbidding the first network within the first retry time, and switching to establish an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network;

and when the timing duration of the first timer reaches the first retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

18. A terminal device, comprising a memory and a processor,

the memory is used for storing a computer program;

after a PDU session is established with a core network of a first network, an IMS network registration request is sent to an IMS network;

if the IMS network registration is not completed within the timing duration of the IMS timer, determining a second retry time of the IMS network registration request and starting a second timer to time, wherein the timing duration of the IMS timer is the longest time required for setting up the PDU session and completing the IMS network registration;

forbidding the first network within the second retry time, and establishing an IMS voice service or a Circuit Switched Fallback (CSFB) voice service by using a second network;

and when the timing duration of the second timer reaches the second retry time, stopping using the second network, and switching to using the first network to establish the IMS voice service.

19. A chip for implementing the functionality of a terminal device according to any of claims 16-18.

20. A computer-readable storage medium for storing a computer program which, when executed by a processor of a terminal device, causes the terminal device to carry out the method of any one of claims 1 to 15.