WO2017128488A1

WO2017128488A1 - Voice call method, voice call device and terminal

Info

Publication number: WO2017128488A1
Application number: PCT/CN2016/074900
Authority: WO
Inventors: 刘建峰
Original assignee: 宇龙计算机通信科技(深圳)有限公司
Priority date: 2016-01-29
Filing date: 2016-02-29
Publication date: 2017-08-03
Also published as: CN105722158B; CN105722158A

Abstract

Provided are a voice call method, a voice call device and a terminal. The voice call method comprises: after initiating an IP multimedia subsystem (IMS) voice call request, determining whether a single radio voice call continuity (SRVCC) call transfer command has been received; if it is determined that the SRVCC call transfer command has been received, switching to a 3G network or a 2G network; determining, according to the SRVCC call transfer command, whether configuration information of a current cell supports a circuit switching domain (CS) service; if a determination result indicates support of the CS service, directly making a CS voice call, otherwise initiating an LAU procedure, a location registration procedure, in the current cell. The technical solution of the invention solves a problem in which after switching to a 3G or 2G network from a 4G network due to an SRVCC call transfer, a CS voice call fails because only a PS service is supported, thereby increasing a call success rate, and improving user experience in a voice call process.

Description

Voice call method, voice call device and terminal

This application claims priority to Chinese Patent Application No. 201610064463.3, entitled "Voice Calling Method, Voice Calling Device and Terminal", which is filed on January 29, 2016, the entire contents of which are incorporated herein by reference. In the application.

Technical field

The present invention relates to the field of terminal technologies, and in particular, to a voice call method, a voice call device, and a terminal.

Background technique

At present, VoLTE technology, Voice over LTE, is an IMS (Multimedia Subsystem)-based voice service. All services are carried on a 4G network, and data and voice services can be unified under the same network. Currently, with the technology of mobile communication With the development, the application of VoLTE technology is more and more extensive. By using VoLTE technology, the call connection waiting time can be shorter and the call quality is higher.

When the existing VoLTE terminal initiates the IMS voice service, the network side evaluates whether the network needs to switch the call to the circuit switched domain CS according to the network coverage quality of the current terminal, and if it needs to switch to the circuit switched domain CS, the SRVCC (voice) is triggered. The business continuity scheme) processes the session transfer so that the voice call is transferred from the 4G network to the 3G network or the 2G network.

However, in the above solution, the current network only supports the PS service, and the call often fails.

Therefore, a new technical solution is needed to improve the success rate of IMS voice calls.

Summary of the invention

The present invention is based on the above problems, and proposes a new technical solution, which can improve the success rate of IMS voice calls.

In view of this, an aspect of the present invention provides a voice call method, including: after initiating a multimedia subsystem IMS voice call request, determining whether to receive a voice service continuity plan SRVCC call transfer instruction; When the voice service continuity plan SRVCC call forwarding instruction is returned to the 3G network or the 2G network; in the 3G network or the 2G network, the current cell is determined according to the voice service continuity plan SRVCC call transfer instruction Whether the configuration information supports the circuit switched domain CS service; when the judgment result is yes, the CS voice call is directly executed, and when the determination result is no, the location registration process LAU is initiated in the current cell for performing the CS voice call. .

In the technical solution, after the IMS voice call request is initiated, the network side evaluates whether the network needs to perform SRVCC call handover according to the network coverage quality of the current terminal, and if necessary, sends an SRVCC call transfer instruction to the current terminal to indicate the current terminal. Detecting the configuration information of the current cell and determining whether the configuration information supports the circuit switched domain CS service. If supported, it indicates that the CS voice call can be effectively performed. If the circuit switched domain CS service is not supported, only the PS service is supported, The location registration process LAU is re-initiated, wherein the location registration process LAU is a location registration process for the location area update initiated by the terminal after selecting the cell, so that the circuit switched domain CS service can be implemented after the registration is successful, which is convenient for further implementation. CS voice call. Through the technical solution, the problem that the CS voice call fails in the case where only the PS service is supported after the SRGCC call transfer is dropped to the 3G or 2G network in the 4G network is avoided, the call success rate of the terminal is increased, and the voice call process is improved. user experience.

Wherein, determining whether the configuration information of the current cell supports the circuit switched domain CS service, specifically calculating the wireless connection rate of the CS of the cell, and the wireless connection rate of the CS is equal to the RAB establishment success rate of the circuit switched domain and the RRC of the circuit switched domain (Radio Resource Control) The product of the connection establishment success rate. Specifically, if the terminal wants to perform the CS domain service in the circuit switched domain, it needs to complete the RRC connection and establish the RAB (Radio Access Bearer). After the RAB is established, the basic call can be realized. The establishment, therefore, when the wireless connection rate of the CS reaches a predetermined threshold, it can be considered that the circuit switched domain CS service can be supported by the cell.

In the foregoing technical solution, preferably, before the determining whether the voice service continuity plan SRVCC call forwarding instruction is received, the method further includes: backing up the call information by calling the management layer CM according to the received IMS voice call instruction, and The 4G network initiates the multimedia subsystem IMS voice call request.

In this technical solution, the user initiates an IMS voice call instruction through the dial pad of the terminal, and Frame Work (the message management layer of the application state) can pass the RIL (the hardware abstraction between the upper layer application and the bottom layer according to the received IMS voice call instruction). The layer sends an IMS voice call request to the call management layer CM, so that the call management layer CM backs up the call information and initiates the IMS call flow.

In any one of the foregoing technical solutions, after the initiating the multimedia subsystem IMS voice call request to the 4G network, the method further includes: detecting whether the SRVCC response information from the 4G network is received, where, when determining And receiving the voice service continuity plan SRVCC call transfer instruction from the SRVCC response information when receiving the SRVCC response information.

In this technical solution, after the Frame Work sends an IMS voice call request to the call management layer CM, it needs to verify in real time whether the SRVCC response information received by the network is received, and only after receiving the SRVCC response information sent back by the network, it indicates that the network needs to fall back. To the 3G or 2G network, it is possible to further detect whether the configuration information of the accessed current cell supports the circuit switched domain CS service. Through this technical solution, the effectiveness and accuracy of the network connection are improved.

In any of the foregoing technical solutions, preferably, the current cell is a UTRAN cell or a GERAN cell.

In the technical solution, the UTRAN cell is a 3G cell, and the GERAN cell is a 2G cell. According to the technical solution, whether the configuration information of the current cell to be accessed supports the circuit switched domain CS service can be used in different types of cells. Improve the success rate of voice call services of different types of cells.

In any one of the foregoing technical solutions, preferably, after determining whether the configuration information of the current cell supports the circuit switched domain CS service, when the determining result is no, the method includes: detecting whether the current call state is a dialing state; When the detection result is yes, the current cell initiates a location registration process LAU for performing a CS voice call after the LAU registration is re-executed; when the detection result is no, the call management layer CM reports the call exception information.

In this technical solution, if it is determined according to the configuration information of the current cell that the current cell does not support the circuit switched domain CS service, and only supports the PS service, the current call state may be further detected. If the current call state is the dialed state, the voice call is in progress. In the process, in order to ensure the smooth progress of the voice call, the LAU registration needs to be re-established immediately, so that the circuit switched domain CS service can be supported after the LAU registration is re-established, and the CS voice call is performed. If the current call state is not in the dialing state, the call abnormality information can be reported directly by the call management layer CM, so that the problem that the CS voice call cannot be successfully implemented is discovered in time.

Another aspect of the present invention provides a voice call apparatus, including: a determining unit, After receiving the multimedia subsystem IMS voice call request, determining whether to receive the voice service continuity plan SRVCC call transfer instruction; the network change unit, when determining to receive the voice service continuity plan SRVCC call transfer instruction, falls back to the 3G network or a 2G network; the determining unit, in the 3G network or the 2G network, determining, according to the voice service continuity plan SRVCC call transfer instruction, whether the configuration information of the current cell supports the circuit switched domain CS service; When the result is YES, the CS voice call is directly executed. When the judgment result is no, the location registration process LAU is initiated in the current cell for performing a CS voice call.

In any one of the foregoing technical solutions, preferably, the method further includes: a call request initiating unit, by calling the management layer according to the received IMS voice call instruction before determining whether to receive the voice service continuity plan SRVCC call transfer instruction The CM backs up the call information and initiates the multimedia subsystem IMS voice call request to the 4G network.

In any one of the foregoing technical solutions, preferably, the method further includes: a response information acknowledgment unit, after detecting the multimedia subsystem IMS voice call request to the 4G network, detecting whether the SRVCC response from the 4G network is received Information, wherein when it is determined that the SRVCC response information is received, the voice service continuity plan SRVCC call transfer instruction is obtained from the SRVCC response information.

In any of the above technical solutions, preferably, the current cell includes a UTRAN cell or a GERAN cell.

In any one of the foregoing technical solutions, preferably, the executing unit includes: a call state detecting unit, when the determining unit determines that the configuration information of the current cell does not support the circuit switched domain CS service, detecting whether the current call state is a dialing state; the LAU re-registration unit, when the call state detecting unit detects that the current call state is a dialing state, initiating a location registration process LAU in the current cell for performing a CS voice call after re-registering the LAU The abnormal information reporting unit reports the call abnormality information by the call management layer CM when the call state detecting unit detects that the current call state is not the dialing state.

In this technical solution, if it is determined according to the configuration information of the current cell that the current cell does not support the circuit switched domain CS service and only supports the PS service, the current call state may be further detected. If the current call state is the dialing state, it indicates that during the voice call, in order to ensure the smooth progress of the voice call, the LAU registration needs to be re-established immediately, so that the circuit switched domain CS service can be supported after the LAU registration is resumed, and the CS voice call is performed. If the current call state is not in the dialing state, the call abnormality information can be reported directly by the call management layer CM, so that the problem that the CS voice call cannot be successfully implemented is discovered in time.

A further aspect of the present invention provides a terminal, the terminal comprising a processor and a memory, wherein the memory stores a set of program codes, and the processor is configured to invoke program code stored in the memory, Do the following:

After initiating the multimedia subsystem IMS voice call request, determining whether to receive the voice service continuity plan SRVCC call transfer instruction;

When it is determined that the voice service continuity plan SRVCC call transfer instruction is received, it falls back to the 3G network or the 2G network;

Determining, in the 3G network or the 2G network, whether the configuration information of the current cell supports the circuit switched domain CS service according to the voice service continuity plan SRVCC call transfer instruction;

When the judgment result is yes, the CS voice call is directly executed, and when the determination result is no, the location registration process LAU is initiated in the current cell for performing the CS voice call.

In the technical solution, before the determining whether to receive the voice service continuity plan SRVCC call transfer instruction, the processor further performs:

According to the received IMS voice call instruction, the call information is backed up by the call management layer CM, and the multimedia subsystem IMS voice call request is initiated to the 4G network.

In the technical solution, after the processor initiates the multimedia subsystem IMS voice call request to the 4G network, the processor further performs:

Detecting whether SRVCC response information from the 4G network is received, wherein the processor acquires the voice service continuity plan SRVCC call transfer instruction from the SRVCC response information when determining that the SRVCC response information is received .

In this technical solution, the current cell is a UTRAN cell or a GERAN cell.

In the technical solution, after the determining whether the configuration information of the current cell supports the circuit switched domain CS service, when the determining result is no, the processor executes:

Detect whether the current call state is a dialing state;

When the detection result is yes, the location registration process LAU is initiated in the current cell for performing a CS voice call after re-registering the LAU;

When the detection result is no, the call abnormality information is reported by the call management layer CM.

Through the above technical solution, the problem that the CS voice call fails in the case where only the PS service is supported after the SRGCC call transfer is dropped to the 3G or 2G network in the 4G network is avoided, the call success rate of the terminal is increased, and the voice call process is improved. user experience.

DRAWINGS

1 shows a flow chart of a method of voice call in accordance with one embodiment of the present invention;

Figure 2 shows a block diagram of a voice call device in accordance with one embodiment of the present invention;

Figure 3 shows a block diagram of a terminal in accordance with one embodiment of the present invention;

4 shows a flow chart of a voice call method in accordance with another embodiment of the present invention;

FIG. 5 shows a block diagram of a terminal in accordance with another embodiment of the present invention.

detailed description

The present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a full understanding of the invention, but the invention may be practiced otherwise than as described herein. Limitations of the embodiments.

FIG. 1 shows a flow chart of a method of voice call in accordance with one embodiment of the present invention.

As shown in FIG. 1, a voice call method according to an embodiment of the present invention includes:

Step 102: After initiating a multimedia subsystem IMS voice call request, determining whether to receive a voice service continuity plan SRVCC call transfer instruction;

Step 104: When it is determined that the voice service continuity plan SRVCC call transfer instruction is received, it falls back to the 3G network or the 2G network;

Step 106, in the 3G network or the 2G network, according to the voice service continuous The SRVCC call transfer instruction determines whether the configuration information of the current cell supports the circuit switched domain CS service;

Step 108: When the determination result is yes, the CS voice call is directly performed. When the determination result is no, the location registration process LAU is initiated in the current cell for performing a CS voice call.

In the foregoing technical solution, preferably, before step 102, the method further includes: backing up the call information by calling the management layer CM according to the received IMS voice call instruction, and initiating the multimedia subsystem IMS voice call request to the 4G network.

In this technical solution, the user initiates an IMS voice call instruction through the dial pad of the terminal, and Frame Work (the message management layer of the application state) can pass the RIL (the hardware abstraction between the upper layer application and the bottom layer according to the received IMS voice call instruction). Layer) issuing an IMS voice call request to The management layer CM is called to call the management layer CM to back up the call information and initiate an IMS call procedure.

In any one of the foregoing technical solutions, after the determining whether the configuration information of the current cell supports the circuit switched domain CS service, in step 108, when the determining result is no, the method includes: detecting whether the current call state is Dialing state; when the detection result is yes, the location registration process LAU is initiated in the current cell for performing a CS voice call after re-registering the LAU; when the detection result is no, the call is reported by the call management layer CM Abnormal information.

2 shows a block diagram of a voice call device in accordance with one embodiment of the present invention.

As shown in FIG. 2, a voice call apparatus 200 according to an embodiment of the present invention includes a determining unit 202, a network changing unit 204, a determining unit 206, and an executing unit 208.

The determining unit 202 is configured to determine, after initiating the multimedia subsystem IMS voice call request, whether to receive the voice service continuity plan SRVCC call transfer instruction; the network change unit 204 is configured to: when determining to receive the voice service continuity plan SRVCC When the call forwarding instruction is returned to the 3G network or the 2G network, the determining unit 206 is configured to determine, according to the voice service continuity plan SRVCC call forwarding instruction, whether the configuration information of the current cell is in the 3G network or the 2G network. Supporting the circuit switched domain CS service; the executing unit 208 is configured to directly perform a CS voice call when the determination result is yes, and when the determination result is no, initiate a location registration process LAU in the current cell for performing CS voice call.

In any one of the foregoing technical solutions, preferably, the call request initiating unit 210, before the determining whether the voice service continuity plan SRVCC call forwarding instruction is received, according to the received IMS voice call instruction, by call management The layer CM backs up the call information and initiates the multimedia subsystem IMS voice call request to the 4G network.

In any one of the foregoing technical solutions, preferably, the method further includes: a response information acknowledgment unit 212, after detecting the multimedia subsystem IMS voice call request to the 4G network, detecting whether the SRVCC from the 4G network is received The response information, wherein when it is determined that the SRVCC response information is received, the voice service continuity plan SRVCC call transfer instruction is obtained from the SRVCC response information.

In any one of the foregoing technical solutions, preferably, the executing unit 208 includes: a call state detecting unit 2082, when the determining unit determines that the configuration information of the current cell does not support the circuit switched domain CS service, detecting whether the current call state is a dialing state; the LAU re-registration unit 2084, when the call state detecting unit detects that the current call state is a dialing state, initiating a location registration procedure LAU in the current cell for performing CS voice after re-registering the LAU The abnormality information reporting unit 2086 reports the call abnormality information by the call management layer CM when the call state detecting unit detects that the current call state is not the dialing state.

Figure 3 shows a block diagram of a terminal in accordance with one embodiment of the present invention.

As shown in FIG. 3, a terminal 300 according to an embodiment of the present invention includes the voice call device 200 shown in FIG. 2. Therefore, the terminal 300 has the same technical effect as the voice call device 200 shown in FIG. This will not be repeated here.

4 shows a flow chart of a method of voice call in accordance with another embodiment of the present invention.

As shown in FIG. 4, a voice call method according to another embodiment of the present invention includes:

In step 402, the terminal registers with the LTE network and registers the IMS service.

Step 404: Receive an IMS voice call instruction at the terminal.

In step 406, the call management layer CM backs up the call information, and initiates an IMS voice service request, waiting for a network response.

In step 408, it is determined whether the SRVCC call transfer request is received. If the determination result is no, the process proceeds to step 410. If the determination result is yes, the process proceeds to step 412.

In step 410, the call flow is continued through the IMS service.

In step 412, the terminal falls back to the 3G network or the 2G network.

In step 414, it is determined whether the configuration of the current UTRAN cell or the GERAN cell supports only the PS service. When the determination result is yes, the process proceeds to step 416. If the determination result is negative, the process proceeds to step 418.

Step 416: It is detected whether the current call state is a dialing state. When the determination result is yes, the process proceeds to step 440. If the determination result is negative, the process proceeds to step 422.

Step 418, continuing the previous CS voice call flow in the cell.

Step 420, initiating a location registration process LAU in the current cell.

In step 422, the call management layer CM reports that the call is abnormal, and terminates the current call.

In step 424, the LAU registration is successful, and the call management layer CM initiates a new circuit switched domain CS call procedure in the cell.

In the above technical solution, the user can initiate a VoLTE voice call through the dial pad of the terminal to form an IMS voice call instruction. Frame Work sends an IMS call command to the module call management layer CM through the hardware abstraction layer, calls the management layer CM to back up the call information, and initiates an IMS call flow, so that the terminal sends an IMS voice call request to the network side, if in the dial-up state, the network The SRVCC flow indication is triggered, and the terminal falls back to the UTRAN cell or the GERAM cell to continue the circuit switched domain CS call.

At this time, the terminal can detect the network configuration. If the UTRAN cell or the GERAN cell of the network configuration only supports the PS service, the call management layer CM suspends the current call and initiates a location registration process LAU in the UTRAN cell or the GERAN cell, and the re-registration is successful. After that, the CS voice call flow before the current network continues to improve the call success rate of the terminal and improve the user experience.

FIG. 5 shows a schematic block diagram of a terminal according to an embodiment of the present invention. As shown in FIG. 5, the terminal 5 may include at least one processor 51, such as a CPU, at least one communication bus 52 and a memory 53, and a communication bus 52. Used to implement connection communication between these components; the memory 53 may be a high speed RAM memory or a non-volatile memory such as at least one disk memory. A set of program codes is stored in the memory 53, and the processor 51 is configured to call the program code stored in the memory 53 for performing the following operations:

When the judgment result is yes, the CS voice call is directly executed, and when the judgment result is no, A location registration process LAU is initiated at the current cell for performing a CS voice call.

In the technical solution, the processor 51 further performs: before determining whether to receive the voice service continuity plan SRVCC call transfer instruction:

In the technical solution, after the processor 51 initiates the multimedia subsystem IMS voice call request to the 4G network, the processor 51 further performs:

In this technical solution, the current cell is a UTRAN cell or a GERAN cell.

In the technical solution, after the determining, by the processor 51, whether the configuration information of the current cell supports the circuit switched domain CS service, when the determining result is no, performing:

Detect whether the current call state is a dialing state;

The technical solution of the present invention is described in detail above with reference to the accompanying drawings. By the technical solution of the present invention, the problem of CS voice call failure in the case where only the PS service is supported after the SRGCC call transfer is dropped to the 3G or 2G network in the 4G network is avoided. The call success rate of the terminal is increased, and the user experience during the voice call is improved.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A voice calling method, comprising:

After initiating the multimedia subsystem IMS voice call request, determining whether to receive the voice service continuity plan SRVCC call transfer instruction;

When it is determined that the voice service continuity plan SRVCC call transfer instruction is received, it falls back to the 3G network or the 2G network;

Determining, in the 3G network or the 2G network, whether the configuration information of the current cell supports the circuit switched domain CS service according to the voice service continuity plan SRVCC call transfer instruction;

When the judgment result is yes, the CS voice call is directly executed, and when the determination result is no, the location registration process LAU is initiated in the current cell for performing the CS voice call.
The voice call method according to claim 1, wherein before the determining whether to receive the voice service continuity plan SRVCC call forwarding instruction, the method further comprises:

According to the received IMS voice call instruction, the call information is backed up by the call management layer CM, and the multimedia subsystem IMS voice call request is initiated to the 4G network.
The voice call method according to claim 2, further comprising: after the initiating the multimedia subsystem IMS voice call request to the 4G network,

Detecting whether SRVCC response information from the 4G network is received, wherein when it is determined that the SRVCC response information is received, the voice service continuity plan SRVCC call transfer instruction is obtained from the SRVCC response information.
The voice call method according to any one of claims 1 to 3, wherein the current cell is a UTRAN cell or a GERAN cell.
The voice call method according to claim 1, wherein after the determining whether the configuration information of the current cell supports the circuit switched domain CS service, when the determining result is no, the method includes:

Detect whether the current call state is a dialing state;

When the detection result is yes, the location registration process LAU is initiated in the current cell for performing a CS voice call after re-registering the LAU;

When the detection result is no, the call abnormality information is reported by the call management layer CM.
A voice call device, comprising:

Determining, after initiating the multimedia subsystem IMS voice call request, determining whether to receive the voice service continuity plan SRVCC call transfer instruction;

The network change unit, when it is determined that the voice service continuity plan SRVCC call transfer instruction is received, falls back to the 3G network or the 2G network;

a determining unit, in the 3G network or the 2G network, determining, according to the voice service continuity plan SRVCC call transfer instruction, whether the configuration information of the current cell supports the circuit switched domain CS service;

The execution unit, when the determination result is yes, directly performs a CS voice call, and when the determination result is no, initiates a location registration process LAU in the current cell for performing a CS voice call.
The voice call device of claim 6, further comprising:

The call request initiating unit, before the determining whether the voice service continuity plan SRVCC call forwarding instruction is received, backs up the call information by calling the management layer CM according to the received IMS voice call instruction, and initiating the multimedia sub-subsidiary to the 4G network System IMS voice call request.
The voice call device of claim 7, further comprising:

a response information acknowledgment unit, after detecting the multimedia subsystem IMS voice call request to the 4G network, detecting whether the SRVCC response message from the 4G network is received, wherein when determining that the SRVCC response message is received And acquiring the voice service continuity plan SRVCC call transfer instruction from the SRVCC response information.
The voice call apparatus according to any one of claims 6 to 8, wherein the current cell comprises a UTRAN cell or a GERAN cell.
The voice call device according to claim 6, wherein the execution unit comprises:

a call state detecting unit, when the determining unit determines that the configuration information of the current cell does not support the circuit switched domain CS service, detecting whether the current call state is a dialing state;

a LAU re-registration unit, when the call state detecting unit detects that the current call state is a dialing state, initiating a location registration process LAU in the current cell for re-running Perform a CS voice call after LAU registration;

The abnormality information reporting unit reports the call abnormality information by the call management layer CM when the call state detecting unit detects that the current call state is not the dialing state.
A terminal, comprising: a processor and a memory, wherein the memory stores a set of program codes, and the processor is configured to call program code stored in the memory for performing the following operations :

After initiating the multimedia subsystem IMS voice call request, determining whether to receive the voice service continuity plan SRVCC call transfer instruction;

When it is determined that the voice service continuity plan SRVCC call transfer instruction is received, it falls back to the 3G network or the 2G network;

Determining, in the 3G network or the 2G network, whether the configuration information of the current cell supports the circuit switched domain CS service according to the voice service continuity plan SRVCC call transfer instruction;

When the judgment result is yes, the CS voice call is directly executed, and when the determination result is no, the location registration process LAU is initiated in the current cell for performing the CS voice call.
The terminal according to claim 11, wherein the processor further performs: before the determining whether the voice service continuity plan SRVCC call forwarding instruction is received, the processor:

According to the received IMS voice call instruction, the call information is backed up by the call management layer CM, and the multimedia subsystem IMS voice call request is initiated to the 4G network.
The terminal according to claim 12, wherein after the initiating the multimedia subsystem IMS voice call request to the 4G network, the processor further performs:

Detecting whether SRVCC response information from the 4G network is received, wherein the processor acquires the voice service continuity plan SRVCC call transfer instruction from the SRVCC response information when determining that the SRVCC response information is received .
The terminal according to any one of claims 11 to 13, wherein the current cell is a UTRAN cell or a GERAN cell.
The terminal according to claim 11, wherein the processor, after determining whether the configuration information of the current cell supports the circuit switched domain CS service, when the determining result is no, performs:

Detect whether the current call state is a dialing state;

When the detection result is yes, the location registration process LAU is initiated in the current cell for performing a CS voice call after re-registering the LAU;

When the detection result is no, the call abnormality information is reported by the call management layer CM.