CN108632803B

CN108632803B - Method and device for switching single-channel continuous service

Info

Publication number: CN108632803B
Application number: CN201710067140.4A
Authority: CN
Inventors: 梁琳琳
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2017-02-06
Filing date: 2017-02-06
Publication date: 2021-11-05
Anticipated expiration: 2037-02-06
Also published as: WO2018141188A1; CN108632803A

Abstract

The embodiment of the invention discloses a method and a device for switching single-channel continuous service. The switching method of the single-channel continuous service in the embodiment of the invention comprises the following steps: a mobile interaction center server (MSCS) sends a Session Initiation Protocol (SIP) establishment request message to an Information Management System (IMS) according to a handover number acquired from a Mobility Management Entity (MME); after receiving the update media message sent by the IMS and the switching detection completion message sent by the target base station, the MSCS sends a single channel continuous Service (SRVCC) switching completion notification message to the MME. The embodiment of the invention solves the problem that the calculated SRVCC switching success rate index is lower due to reasons of untimely message processing, compatibility and the like of network elements in an IMS in the prior art when the SRVCC switching process is executed.

Description

Method and device for switching single-channel continuous service

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to a method and an apparatus for switching a single-channel continuous service.

Background

With the development and popularization of wireless communication technology, wireless communication networks have been applied to various aspects of people's daily lives. For example, a Voice over LTE (Voice over LTE) based Information Management System (IMS) has been proposed in a Long Term Evolution (LTE) System.

The current mainstream LTE voice solution is to deploy an IMS network and corresponding application servers to provide VoLTE. In a scenario using VoLTE, a problem that a Voice Call may be interrupted due to insufficient network coverage at an initial stage is encountered, and a Single Radio Voice Call Continuity (SRVCC) technology may switch a 4G Voice Call to a 2G or 3G network when a 4th Generation (4G) signal is weak, and a second Generation (2G) or third Generation (3 rd-Generation) signal is strong, so as to solve a problem of network deployment at the initial stage of 4G. SRVCC is a solution for providing single channel voice continuity by using an IMS voice service network accessed by LTE, when User Equipment (UE) moves from LTE to a Client/Server (CS), SRVCC establishes a CS branch and anchors a network element in IMS, and a CS call and an original IMS call are connected through the anchored network element, thereby forming a complete call chain and keeping the call of the original IMS domain to be continued after switching. However, after receiving a Handover request message sent by a Mobility Management Entity (MME) and according to a Handover number carried in the message, a Mobile Switching Center (MSC) Server (MSCs) initiates a Session Initiation Protocol (SIP) establishment request procedure to the IMS, and after receiving an update media message (18X), a Handover Detection (Handover Detection, HO) completion message, and an INFO message, sends an SRVCC Handover completion notification message to the MME and calculates an SRVCC Handover success rate.

In the process of executing SRVCC handover in the prior art, the calculated index of the SRVCC handover success rate is low due to reasons such as untimely message processing and compatibility of network elements in the IMS, and it is difficult to meet the requirement of the operator on the SRVCC handover success rate.

Disclosure of Invention

In order to solve the above technical problems, embodiments of the present invention provide a method and an apparatus for switching a single-channel continuous service, so as to solve the problem that, in the process of performing SRVCC handover in the prior art, an index of a calculated SRVCC handover success rate is low due to reasons such as untimely message processing and compatibility of a network element in an IMS.

In a first aspect, an embodiment of the present invention provides a method for switching a single-channel continuous service, including:

a mobile interaction center server (MSCS) sends a Session Initiation Protocol (SIP) establishment request message to an Information Management System (IMS) according to a switching number acquired from a Mobility Management Entity (MME);

and after receiving the update media message sent by the IMS and the switching detection completion message sent by the target base station, the MSCS sends a single-channel continuous service SRVCC switching completion notification message to the MME.

In a first possible implementation manner of the first aspect, before the MSCS sends the SIP setup request message to the IMS, the method includes:

the MSCS receives an SRVCC switching request message sent by the MME, wherein the SRVCC switching request message comprises the switching number and the identification information of the target base station;

the MSCS sends a switching detection request message to the target base station according to the identification information of the target base station;

and the MSCS receives a switching detection response message sent by the target base station, wherein the switching detection response message is used for indicating that the target base station has the capability of allocating wireless resources.

According to a first possible implementation manner of the first aspect, in a second possible implementation manner, the method further includes:

and the MSCS calculates the SRVCC switching success rate according to the times of sending the SRVCC switching completion notification message and the times of receiving the SRVCC switching request message.

According to the first possible implementation manner of the first aspect, in a third possible implementation manner, a timer is set in the MSCS, and after the MSCS sends the SIP establishment request message to the IMS, the method further includes:

the MSCS starts the timer;

after the MSCS sends an SRVCC handover complete notification message to the MME, the method further includes:

and when the timer does not receive the INFO message sent by the IMS after reaching the preset time, sending a notification message of canceling the SRVCC switching to the MME.

According to a third possible implementation manner of the first aspect, in a fourth possible implementation manner, the method further includes:

and the MSCS calculates the SRVCC switching success rate according to the times of sending the SRVCC switching completion notification message, the times of receiving the SRVCC switching request message and the times of sending the SRVCC switching cancellation notification message.

In a second aspect, an embodiment of the present invention provides a method for switching a single-channel continuous service, including:

a mobility management entity MME sends a single-channel continuous service SRVCC switching request message to a mobile interaction center server MSCS;

and the MME receives an SRVCC switching completion notification message sent by the MSCS, wherein the SRVCC switching completion notification message is sent to the MME by the MSCS after receiving an update media message sent by an Information Management System (IMS) and a switching detection completion message sent by a target base station.

In a first possible implementation manner of the second aspect, the SRVCC handover request message includes identification information of a target base station, where the SRVCC handover request message is used to instruct the MSCS to send a handover detection request message to the target base station according to the identification information of the target base station, and receive a handover detection response message sent by the target base station, where the handover detection response message is used to instruct the target base station to have a capability of allocating radio resources.

In a second possible implementation manner of the second aspect, the SRVCC handover request message includes a handover number, and the SRVCC handover request message is used to instruct the MSCS to send a session initiation protocol SIP establishment request message to the IMS according to the handover number.

According to the second aspect, and any one of the first and second possible implementation manners of the second aspect, in a third possible implementation manner, the method further includes:

and the MME calculates the SRVCC switching success rate according to the times of receiving the SRVCC switching completion notification message and the times of sending the SRVCC switching request message.

According to the second aspect, or any one of the first and second possible implementation manners of the second aspect, in a fourth possible implementation manner, the method further includes:

the MME receives a notification message for canceling SRVCC handover sent by the MSCS;

and the MME calculates the SRVCC switching success rate according to the times of receiving the SRVCC switching completion notification message, the times of sending the SRVCC switching request message and the times of receiving the SRVCC switching cancellation notification message.

In a third aspect, an embodiment of the present invention provides a device for switching a single-channel continuous service, where the device is disposed in a mobile interaction center server MSCS, and the device includes:

a sending module, configured to send a session initiation protocol SIP establishment request message to an information management system IMS according to a handover number acquired from a mobility management entity MME;

a receiving module, configured to receive an update media message sent by the IMS and a handover detection completion message sent by a target base station;

the sending module is further configured to send a single-channel continuous service SRVCC handover complete notification message to the MME after the receiving module receives the update media message and the handover detection complete message.

In a first possible implementation manner of the third aspect, the receiving module is further configured to receive, before the sending module sends an SIP setup request message to an IMS, an SRVCC handover request message sent by the MME, where the SRVCC handover request message includes the handover number and the identification information of the target base station;

the sending module is further configured to send a handover detection request message to the target base station according to the identification information of the target base station received by the receiving module;

the receiving module is further configured to receive a handover detection response message sent by the target base station, where the handover detection response message is used to indicate that the target base station has a capability of allocating radio resources.

According to a first possible implementation manner of the third aspect, in a second possible implementation manner, the apparatus further includes:

and the calculating module is used for calculating the SRVCC switching success rate according to the times of sending the SRVCC switching completion notification message by the sending module and the times of receiving the SRVCC switching request message by the receiving module.

According to the first possible implementation manner of the third aspect, in a third possible implementation manner, a timer is provided in the MSCS, and the apparatus further includes:

the starting module is used for starting the timer after the sending module sends the SIP establishment request message to the IMS;

the sending module is further configured to send a notification message for canceling SRVCC handover to the MME when the timer reaches a preset time and does not receive the INFO message sent by the IMS.

According to a third possible implementation manner of the third aspect, in a fourth possible implementation manner, the apparatus further includes:

and the calculating module is used for calculating the SRVCC switching success rate according to the times of sending the SRVCC switching completion notification message by the sending module, the times of receiving the SRVCC switching request message by the receiving module and the times of sending the SRVCC switching cancellation notification message by the sending module.

In a fourth aspect, an embodiment of the present invention provides a device for switching a single-channel continuous service, where the device is disposed in a mobility management entity MME, and the device includes:

a sending module, which is used for sending a single-channel continuous service SRVCC switching request message to a mobile interaction center server MSCS;

a receiving module, configured to receive an SRVCC handover complete notification message sent by the MSCS, where the SRVCC handover complete notification message is sent by the MSCS to the MME after receiving an update media message sent by an information management system IMS and a handover detection complete message sent by a target base station.

In a first possible implementation manner of the fourth aspect, the SRVCC handover request message includes identification information of a target base station, where the SRVCC handover request message is used to instruct the MSCS to send a handover detection request message to the target base station according to the identification information of the target base station, and receive a handover detection response message sent by the target base station, where the handover detection response message is used to instruct the target base station to have a capability of allocating radio resources.

In a second possible implementation manner of the fourth aspect, the SRVCC handover request message includes a handover number, and the SRVCC handover request message is used to instruct the MSCS to send a session initiation protocol SIP establishment request message to the IMS according to the handover number.

According to the fourth aspect, as well as any one of the first and second possible implementation manners of the fourth aspect, in a third possible implementation manner, the apparatus further includes:

and the calculating module is used for calculating the SRVCC switching success rate according to the times of receiving the SRVCC switching completion notification message by the receiving module and the times of sending the SRVCC switching request message by the sending module.

According to the fourth aspect, or any one of the first and second possible implementation manners of the fourth aspect, in a fourth possible implementation manner, the receiving module is further configured to receive a cancel SRVCC handover notification message sent by the MSCS;

the device further comprises:

and the calculating module is used for calculating the SRVCC switching success rate according to the times of receiving the SRVCC switching completion notification message by the receiving module, the times of sending the SRVCC switching request message by the sending module and the times of receiving the SRVCC switching cancellation notification message by the receiving module.

The method and the device for switching the single-channel continuous service provided by the embodiment of the invention send the SIP establishment request message to the IMS through the MSCS according to the switching number acquired from the MME, and then the MSCS sends the SRVCC switching completion notification message to the MME after receiving the update media message sent by the IMS and the switching detection completion message sent by the target base station, namely, the MSCS can send the SRVCC switching completion notification message to the MME without waiting for the INFO message returned by the IMS, thereby avoiding that the IMS does not return the INFO message for a long time, leading the MME not to receive the SRVCC switching completion notification message for a long time, actively sending the SRVCC switching cancellation message to the MSCS to notify the MSCS to release the call, and being beneficial to improving the SRVCC switching success rate; the technical scheme provided by the embodiment of the invention solves the problem that the calculated index of the SRVCC switching success rate is lower in the process of executing the SRVCC switching in the prior art due to reasons of untimely message processing, compatibility and the like of a network element in an IMS.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention and not to limit the invention.

Fig. 1 is a schematic view of an application scenario of a handover method of SRVCC;

fig. 2 is a signaling interaction flow diagram of an SRVCC handover method provided in the prior art;

fig. 3 is a signaling interaction flow diagram of another SRVCC handover method provided in the prior art;

fig. 4 is a flowchart of a handover method of SRVCC according to an embodiment of the present invention;

fig. 5 is a flowchart of another SRVCC handover method according to an embodiment of the present invention;

fig. 6 is a flowchart of a handover method of SRVCC according to another embodiment of the present invention;

fig. 7 is a flowchart of a handover method of SRVCC according to another embodiment of the present invention;

fig. 8 is a flowchart of a handover method of SRVCC according to another embodiment of the present invention;

fig. 9 is a flowchart of a handover method of SRVCC according to another embodiment of the present invention;

fig. 10 is a signaling interaction flowchart of a SRVCC handover method according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of a switching apparatus of SRVCC according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of another SRVCC handover apparatus according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of a switching apparatus of SRVCC according to an embodiment of the present invention;

fig. 14 is a schematic structural diagram of a switching apparatus of SRVCC according to another embodiment of the present invention;

fig. 15 is a schematic structural diagram of a switching apparatus of SRVCC according to another embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

The steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.

SRVCC is proposed in the third Generation Partnership Project (3rd Generation Partnership Project, abbreviated as 3GPP) to solve the problem that a Voice call may be interrupted due to incomplete network coverage in an initial period in a scenario of using VoLTE, and mainly solves the problem of how to ensure Voice call continuity when a UE moves to a 2G/3G CS in an LTE network, that is, to ensure smooth handover of the UE between Voice over Internet Protocol (VoIP) Voice and CS domain Voice under IMS control.

Fig. 1 is a schematic view of an application scenario of a SRVCC handover method. In the application scenario, when the UE moves from a 4G network covered by an Evolved Node B (eNB) to a 2G network covered by a Base Station Controller (BSC), after receiving an SRVCC handover request message sent by an MME, the MSCS exchanges a handover detection request message and a handover detection response message with a target Base Station, and allocates related radio resources on the target Base Station; the MSCS initiates an SIP establishment request process of the IMS according to the switching number, simultaneously, the target base station performs a switching detection process, and sends a switching detection completion message to the MSCS after the switching is completed, and when the subsequent MSCS sends an SRVCC switching completion notification message to the MME is an important factor influencing the SRVCC switching success rate; IMS in fig. 1 refers to network elements anchored in IMS, for example: a Service centralized and continuous Application Server (SCC AS for short), a Session Border Controller (SBC for short)/an access transmission Control function (ATCF for short), or other network elements; the SAE-GW in FIG. 1 is an SAE Gateway (SAE Gateway). As shown in fig. 2, a signaling interaction flowchart of an SRVCC handover method provided in the prior art is provided, where the method for performing SRVCC handover in the prior art may include the following steps, i.e., S101 to S113:

s101, MSCS receives SRVCC switching request message sent by MME, the SRVCC switching request message includes switching number;

s102, MSCS sends switch detection request message to target base station;

s103, the target base station feeds back a switching detection response message to the MSCS, wherein the switching detection response message is used for indicating that the target base station can allocate related resources;

s104, MSCS sends SRVCC switching response message to MME;

s105, the MSCS initiates a session transfer process according to the switching number, namely, sends an SIP establishment request message to the IMS;

it should be noted that S104 and S105 do not have a definite sequence, and may be executed sequentially or simultaneously.

S106, MSCS receives the update media message (18X message) sent by IMS, the update media message is marked with INFO packet supported by IMS;

s107, after the target base station performs switching detection, the target BSS sends a switching detection completion message to the MSCS;

s108, the MSCS returns a response message of completing the switching detection to the target base station;

s109, MSCS sends PRACK message to IMS, the PRACK message is the confirmation request message of updating media message in S106;

it should be noted that S108 and S109 do not have a definite sequence, and may be executed sequentially or simultaneously.

S110, IMS returns 200OK information to MSCS, the 200OK information is response information to the update media information in S106;

s111, MSCS receives INFO message sent by IMS;

s112, after receiving the INFO message, the MSCS sends an SRVCC switching completion notification message to the MME; then, the MSCS calculates the SRVCC handover success rate, and the calculation formula of the SRVCC handover success rate is:

the SRVCC handover success rate is the number of SRVCC handover complete notification messages/the number of SRVCC handover request messages 100%.

S113, the MME returns an SRVCC completion notification response message to the MSCS.

In the process of S104 to S111, the MME waits for the SRVCC handover complete notification message sent by the MSCS, and in this process, the IMS side returns a message in time, and the IMS side is incompatible, which may cause the MME to send a SRVCC handover cancel message to the MSCS, so that the SRVCC handover success rate is reduced. As shown in fig. 3, a signaling interaction flowchart of another SRVCC handover method provided in the prior art is provided, where the method for performing SRVCC handover in the prior art may include the following steps, i.e., S201 to S211:

in a specific implementation, S201 to S210 in the flow shown in fig. 3 may refer to S101 to S110 in the flow shown in fig. 2, and therefore, the details are not repeated herein.

S211, MME sends SRVCC switching cancel message to MSCS.

In the flow shown in fig. 3, because the MSCS does not receive the INFO message sent by the IMS for a long time, after the MME does not receive the SRVCC handover complete notification message when timeout occurs, the MME sends an SRVCC handover cancel message to the MSCS, thereby causing a handover failure and reducing the SRVCC handover success rate.

As described above, there are many network elements involved in the SRVCC handover process, and the timing sequence of each message is not well controlled, and especially in an application scenario where different manufacturers are docked, how to improve the SRVCC handover success rate becomes a problem that needs to be solved at present.

The following describes in detail a technical solution of the present invention with specific embodiments, and the present invention relates to an MME, an MSCS, a target base station, and a network element in an IMS, where the network element in the IMS is a network element in a 4G network, the MSCS and the target base station are network elements in a 2G/3G network, and the MME performs message interaction with a base station and a gateway in the 4G network, and the MSCS in the 2G/3G network, respectively (as shown in fig. 1). The following specific embodiments of the present invention may be combined, and the same or similar concepts or processes may not be described in detail in some embodiments.

Fig. 4 is a flowchart of a handover method of SRVCC according to an embodiment of the present invention. The SRVCC handover method provided in this embodiment is applicable to a case where the UE performs SRVCC handover when moving from the 4G network to the 2G/3G network, and the method may be executed by a handover device of SRVCC, where the handover device of SRVCC is implemented by combining hardware and software, and the handover device may be integrated in a processor of an MSCS for being invoked by the processor. As shown in fig. 4, the method of this embodiment may include:

s110, MSCS sends SIP establishment request message to IMS according to the switching number obtained from MME.

The SRVCC switching method provided by the embodiment of the invention is a mode for solving how to improve the SRVCC switching success rate in the process of executing SRVCC switching when UE moves from a 4G network to a 2G/3G network. As shown in fig. 1, because the MME is configured to perform UE reachability management, when the UE moves from a 4G network to a 2G/3G network, the MME sends an SRVCC handover request message to the MSCS, and the message carries a handover number to be SRVCC handed over, the MSCS may send an SIP establishment request message to the IMS according to the handover number acquired from the MME.

It should be noted that IMS in the embodiment of the present invention refers to a network element anchored in IMS after a UE moves to a 2G/3G network and a C/S branch is established, for example, SCC AS, SBC/ATCF, or other network elements, and does not refer to the entire system of IMS.

S120, after receiving the update media message sent by IMS and the switch detection completion message sent by the target base station, MSCS sends an SRVCC switch completion notification message to MME.

In the embodiment of the present invention, the time when the MSCS sends the SRVCC handover complete notification message to the MME is different from the time when the MSCS sends the SRVCC handover complete notification message in the prior art, and specifically, after receiving the update media message sent by the IMS and the handover detection complete message sent by the target base station, the MSCS can immediately send the SRVCC handover complete notification message to the MME. According to the method provided by the embodiment of the invention, the MSCS can directly send the SRVCC switching completion notification message to the MME without waiting for the INFO message returned by the IMS side, so that the phenomenon that the MME cannot receive the SRVCC switching completion notification message for a long time because the IMS does not return the INFO message for a long time after the MSCS finishes sending the SIP establishment request message is avoided, and the SRVCC switching cancellation message is actively sent to the MSCS to notify the MSCS of call release.

It should be noted that the update media message is an 18X message, and may include 180, 181, 182, and 183, for example, when 180 indicates ringing and 183 indicates a call back is in progress; the INFO message is an optional message for sending application layers that are typically related to the conference.

As described in the above background art, in the process of performing SRVCC handover in the prior art, after receiving an SRVCC handover request message sent by an MME, an MSCS may exchange a handover detection request message and a handover detection response message with a target base station first, after the exchange is completed, the MSCS may interact with the MME and an IMS at the same time, send an SRVCC handover response message to the MME and send an SIP establishment request message to the IMS, and then, the MSCS may wait for a handover detection completion message returned by the target base station and an 18X message and an INFO message returned by the IMS; however, because of the problem of message timing sequence of different manufacturers in the network deployment process, in the process that the MSCS waits for the INFO message sent by the IMS, the MME actively sends an SRVCC handover cancel message to the MSCS after not receiving the SRVCC handover complete notification message sent by the MSCS for a long time, and notifies the MSCS to release the call. Compared with the method for executing SRVCC handover in the prior art, in the SRVCC handover method provided by the embodiment of the invention, MSCS does not need to wait for an INFO message returned by IMS, and can send an SRVCC handover completion notification message to MME as long as an 18X message sent by IMS and a handover detection completion message sent by a target base station are received; it can be seen that, by optimizing the handover procedure at the MSCS side, the method provided by the embodiment of the present invention does not affect the early cancellation of the handover procedure even if the time for the IMS to return the INFO message is long, and achieves the purpose of ensuring that the MME does not overtime in advance, thereby ensuring the smooth completion of the handover procedure, improving the success rate of SRVCC handover, and accordingly, enhancing the user experience effect of the operator on MSCS products.

In the SRVCC handover method provided in this embodiment, the MSCS sends the SIP establishment request message to the IMS according to the handover number acquired from the MME, and then, after receiving the update media message sent by the IMS and the handover detection completion message sent by the target base station, the MSCS sends the SRVCC handover completion notification message to the MME, that is, the MSCS can send the SRVCC handover completion notification message to the MME without waiting for the INFO message returned by the IMS, thereby avoiding that the IMS does not return the INFO message for a long time, and thus the MME cannot receive the SRVCC handover completion notification message for a long time, and actively sending the SRVCC handover cancellation message to the MSCS to notify the MSCS of the release of the call, which is beneficial to improving the success rate of SRVCC handover; the method provided by the embodiment solves the problem that in the prior art, in the process of executing the SRVCC handover, the calculated index of the SRVCC handover success rate is low due to reasons such as untimely message processing and compatibility of the network element in the IMS.

Optionally, fig. 5 is a flowchart of another SRVCC handover method according to an embodiment of the present invention. On the basis of the embodiment shown in fig. 4, before S110, the method provided in the embodiment of the present invention may further include:

s100, MSCS receives SRVCC switching request message sent by MME, the SRVCC switching request message includes switching number and identification information of target base station;

s101, MSCS sends switching detection request message to target base station according to identification information of target base station;

s102, the MSCS receives a switching detection response message sent by the target base station, wherein the switching detection response message is used for indicating that the target base station has the capability of allocating wireless resources.

In the embodiment of the present invention, it has been described above that the MSCS sends the SIP establishment request message according to the handover number acquired from the MME, and in practical applications, the manner in which the MSCS acquires the handover number and the radio resource is as follows: when UE moves from 4G network to 2G/3G network, MME confirms target base station according to UE movement and sends SRVCC switching request message carrying switching number and identification information of target base station to MSCS, then MSCS interacts switching detection request message and switching detection response message with target base station according to the obtained message, and obtains that the target base station can distribute wireless resource from switching detection response message, namely has switching capability. In addition, the MSCS initiates a call back migration procedure according to the handover number acquired from S100, that is, sends a SIP setup request message to the IMS.

Further, after S120, the method provided in the embodiment of the present invention may further include:

s130, MSCS calculates SRVCC switching success rate according to the times of sending SRVCC switching completion notice message and the times of receiving SRVCC switching request message.

As already described above, the calculation formula of the SRVCC handover success rate is:

In the method provided in the embodiment of the present invention, the above steps S100 to S120 may be repeatedly performed, and as long as the condition that the UE moves from the 4G network to the 2G/3G network is satisfied, the steps S100 to S120 are performed. Therefore, the MSCS can calculate the SRVCC handover success rate within a certain preset time period according to the number of times of sending the SRVCC handover completion notification message and the number of times of receiving the SRVCC handover request message.

Due to the method provided by the embodiment of the invention, the MSCS can send the SRVCC switching completion notification message to the MME without waiting for the INFO message returned by the IMS, thereby improving the SRVCC switching success rate to a certain extent.

It should be noted that, as a result of statistics of a certain commercial environment in an external field, in the process of performing SRVCC handover in the prior art, the time length for the IMS to return an INFO message is long, which results in a decrease in the success rate of SRVCC handover by about 20%, and actually, the data difference is still large in different commercial environments.

Optionally, a timer may be set in the MSCS in the embodiment of the present invention, as shown in fig. 6, which is a flowchart of another SRVCC handover method provided in the embodiment of the present invention. On the basis of the embodiment shown in fig. 5, after S110, the method provided in the embodiment of the present invention may further include:

s111, MSCS starts a timer;

after S120, the method may further include:

s121, when the timer reaches the preset time and does not receive the INFO message sent by the IMS, sending a notification message for canceling SRVCC switching to the MME.

In the embodiment of the present invention, a certain time may be reserved on the MSCS side to wait for the INFO message returned by the IMS, that is, the timer may be started after the MSCS sends the SIP establishment request message to wait for the INFO message returned by the subsequent IMS by setting the timer in the MSCS, and if the INFO message is not received within the preset time, the MSCS may actively send a cancel SRVCC handover notification message to the MME to release the current call.

In this embodiment, the way for the MSCS to calculate the SRVCC handover success rate, that is, the implementation way of S130 may be: the MSCS calculates the SRVCC switching success rate according to the times of sending the SRVCC switching completion notification message, the times of receiving the SRVCC switching request message and the times of sending the SRVCC switching cancellation notification message. In practical application, the calculation formula of the SRVCC handover success rate may be:

the SRVCC handover success rate is (the number of times the SRVCC handover complete notification message is completed-the number of times the SRVCC handover notification message is cancelled)/the number of times the SRVCC handover request message is 100%.

It can be seen from the above formula for calculating the success rate of SRVCC handover that, although the mode of MSCS actively releasing the current call will reduce the index of the calculated success rate of SRVCC handover, the current situation of low success rate is known to be caused by the fact that no INFO message is sent due to the problem of IMS network element compatibility, and therefore, the index of the success rate of SRVCC handover on the MSCS side will not be affected. The embodiment of the invention can enhance the compatibility of the network element and effectively improve the SRVCC switching success rate by reasonably optimizing the SRVCC switching process, thereby meeting the operation and maintenance requirements.

In this embodiment of the present invention, after S102, the method for switching SRVCC shown in fig. 5 and fig. 6 may further include: MSCS sends SRVCC switching response message to MME; it should be noted that the embodiment of the present invention does not limit the sequence of sending the SRVCC handover response message and sending the SIP setup request message by the MSCS.

In this embodiment of the present invention, before S120, the method for switching SRVCC shown in fig. 5 and fig. 6 may further include:

MSCS receives 18X message sent by IMS, MSCS receives switching detection completion message sent by target base station; it should be noted that the embodiment of the present invention does not limit the sequence of receiving the 18X message and the handover detection complete message by the MSCS.

In addition, after receiving the handover detection complete message, the MSCS may further include:

MSCS sends switching detection completion response message to target base station, MSCS sends PRACK message to IMS, MSCS receives 200OK message sent by IMS, MSCS receives INFO message sent by IMS; it should be noted that the embodiment of the present invention does not limit the sequence of the MSCS sending the handover detection completion response message, sending the PRACK message, and receiving the INFO message.

In this embodiment of the present invention, after S120, the method for switching SRVCC shown in fig. 5 and fig. 6 may further include:

and the MSCS receives the SRVCC switching completion notification response message returned by the MME, and then ends the switching process.

Fig. 7 is a flowchart of a handover method for SRVCC according to another embodiment of the present invention. The SRVCC handover method provided in this embodiment is applicable to a case where the UE performs SRVCC handover when moving from the 4G network to the 2G/3G network, and the method may be executed by a handover device of SRVCC, where the handover device of SRVCC is implemented by combining hardware and software, and the handover device may be integrated in a processor of an MME for the processor to call. As shown in fig. 7, the method of this embodiment may include:

s210, the MME sends an SRVCC handover request message to the MSCS.

The SRVCC switching method provided by the embodiment of the invention is a mode for solving how to improve the SRVCC switching success rate in the process of executing SRVCC switching when UE moves from a 4G network to a 2G/3G network. As shown in fig. 1, because the MME is configured to perform UE reachability management, when the UE moves from a 4G network to a 2G/3G network, the MME may send an SRVCC handover request message to the MSCS, and the message carries a handover number to be SRVCC handed over, so that the MSCS may send an SIP establishment request message to the IMS according to the handover number acquired from the MME.

S220, MME receives SRVCC switching completion notification message sent by MSCS, the SRVCC switching completion notification message is sent to MME after MSCS receives the update media message sent by IMS and the switching detection completion message sent by target base station.

In the embodiment of the present invention, the time when the MSCS sends the SRVCC handover complete notification message to the MME is different from the time when the MSCS sends the SRVCC handover complete notification message in the prior art, and specifically, after receiving the update media message sent by the IMS and the handover detection complete message sent by the target base station, the MSCS can immediately send the SRVCC handover complete notification message to the MME. According to the method provided by the embodiment of the invention, the MSCS can directly send the SRVCC switching completion notification message to the MME without waiting for the INFO message returned by the IMS side, and the MME can receive the SRVCC switching completion notification message in a short time, so that the phenomenon that the IMS does not return the INFO message for a long time after the MSCS sends the SIP establishment request message, the MME cannot receive the SRVCC switching completion notification message for a long time, and the SRVCC switching cancellation message is actively sent to the MSCS to notify the MSCS of call release is avoided.

It should be noted that IMS in the embodiment of the present invention refers to a network element anchored in IMS after a UE moves to a 2G/3G network and a C/S branch is established, for example, SCC AS, SBC/ATCF, or other network elements, and does not refer to the entire system of IMS. In addition, the update media message is an 18X message, and may include 180, 181, 182, and 183, for example, when 180 indicates ringing and 183 indicates call back is in progress; the INFO message is an optional message for sending application layers that are typically related to the conference.

In the SRVCC handover method provided in this embodiment, an MME sends an SRVCC handover request message to an MSCS, and receives an SRVCC handover completion notification message sent by the MSCS, where the SRVCC handover completion notification message is sent by the MSCS to the MME after receiving an update media message sent by an information management system IMS and a handover detection completion message sent by a target base station, that is, the MSCS can send the SRVCC handover completion notification message to the MME without waiting for an INFO message returned by the IMS, thereby avoiding that the IMS does not return an INFO message for a long time, and the MME does not receive the SRVCC handover completion notification message for a long time, and thus actively sending an SRVCC handover cancel message to the MSCS to notify the MSCS of a call release, which is beneficial to improving a vcc SRVCC handover success rate; the method provided by the embodiment solves the problem that in the prior art, in the process of executing the SRVCC handover, the calculated index of the SRVCC handover success rate is low due to reasons such as untimely message processing and compatibility of the network element in the IMS.

In this embodiment of the present invention, the SRVCC handover request message sent by the MME in S210 includes identification information of the target base station, where the SRVCC handover request message is used to instruct the MSCS to send a handover detection request message to the target base station according to the identification information of the target base station, and receive a handover detection response message sent by the target base station, and the handover detection response message is used to instruct the target base station to have a capability of allocating radio resources. That is to say, after acquiring the identification information of the target base station by receiving the SRVCC handover request message, the MSCS may interact the handover detection request message and the handover detection response message with the target base station according to the identification information of the target base station, and learn from the handover detection response message that the base station can perform the allocation of radio resources, that is, has the handover capability.

In this embodiment of the present invention, the SRVCC handover request message sent by the MME in S210 may further include a handover number, where the SRVCC handover request message is further used to instruct the MSCS to send a session initiation protocol SIP establishment request message to the IMS according to the handover number. That is, after acquiring the handover number by receiving the SRVCC handover request message, the MSCS may send the SIP establishment request message to the IMS according to the handover number. In practical application, the way for the MSCS to acquire the handover number and radio resources is: when UE moves from 4G network to 2G/3G network, MME confirms target base station according to UE movement and sends SRVCC switching request message carrying switching number and identification information of target base station to MSCS, then MSCS carries out interaction of switching detection request message and switching detection response message with target base station according to the obtained message, and obtains wireless resource distributed for switching number by target base station from switching detection response message. In addition, the MSCS initiates a call-back migration process according to the switching number acquired from the SRVCC switching request message, namely, sends an SIP establishment request message to the IMS.

Optionally, fig. 8 is a flowchart of a handover method of SRVCC according to an embodiment of the present invention. On the basis of the embodiment shown in fig. 7, after S220, the method provided by the embodiment of the present invention may further include:

s230, the MME calculates the success rate of SRVCC switching according to the times of receiving the SRVCC switching completion notification message and the times of sending the SRVCC switching request message.

In the above embodiment, it has been described that the calculation formula of the SRVCC handover success rate is:

It should be noted that, in the method provided in the embodiment of the present invention, the above steps S210 to S220 and the steps executed by the MSCS side may be repeatedly executed, as long as the condition that the UE moves from the 4G network to the 2G/3G network is satisfied, the MME executes steps S210 to S220, and the MSCS executes corresponding steps. Therefore, the MME may calculate, within a certain preset time period, the SRVCC handover success rate within the time period according to the number of times of receiving the SRVCC handover completion notification message and the number of times of sending the SRVCC handover request message.

Optionally, as shown in fig. 9, a flowchart of a handover method for SRVCC according to another embodiment of the present invention is provided. On the basis of the embodiment shown in fig. 7, after S220, the method provided by the embodiment of the present invention may further include:

s240, the MME receives the SRVCC switching cancellation notification message sent by the MSCS.

In the embodiment of the present invention, a certain time may be reserved on the MSCS side to wait for the INFO message returned by the IMS, that is, the timer may be started to wait for the INFO message returned by the subsequent IMS in a manner that the MSCS is provided with the timer after the MSCS sends the SIP establishment request message to the IMS, and if the INFO message is not received within the preset time, the MSCS may actively send a cancel SRVCC handover notification message to the MME to release the current call. Therefore, after receiving the SRVCC handover complete notification message, the MME in the embodiment of the present invention may also receive a cancel SRVCC handover notification message for releasing the current call.

Further, the method provided by this embodiment may further include:

s250, the MME calculates the SRVCC switching success rate according to the times of receiving the SRVCC switching completion notification message, the times of sending the SRVCC switching request message and the times of receiving the SRVCC switching cancellation notification message.

In practical application, the calculation formula of the SRVCC handover success rate may be:

In this embodiment of the present invention, after the MME sends the SRVCC handover request message to the MSCS, the method for handover of SRVCC shown in fig. 8 and 9 may further include an operation of interaction between the MSCS and the target base station, and between the IMS and the MME, which are already described in detail in the above embodiment in which the MSCS is used as an execution subject, and therefore, details are not described here again.

Fig. 10 is a signaling interaction flowchart of a SRVCC handover method according to an embodiment of the present invention. The handover method of SRVCC shown in fig. 9 may include the following steps:

s301, MSCS receives SRVCC switching request message sent by MME, the SRVCC switching request message includes switching number and identification information of target base station;

s302, MSCS sends switching detection request message to the target base station according to the identification information of the target base station;

s303, the target base station feeds back a switching detection response message to the MSCS, wherein the switching detection response message is used for indicating that the target base station can allocate related resources and has switching capability;

s304, MSCS sends SRVCC switching response message to MME;

s305, the MSCS initiates a session transfer process according to the switching number, namely, sends an SIP establishment request message to the IMS;

it should be noted that in this embodiment, S304 and S305 have no explicit sequence, and may be executed sequentially or simultaneously.

S306, MSCS receives 18X message sent by IMS, the 18X message is marked with INFO packet supported by IMS;

s307, after the target base station performs switching detection, the target BSS sends a switching detection completion message to the MSCS;

it should be noted that in this embodiment, S306 and S307 do not have a definite sequence, and may be executed sequentially or simultaneously.

S308, MSCS sends SRVCC switching completion notice message to MME; then, the MSCS can calculate the SRVCC handover success rate, and the calculation method of the SRVCC handover success rate has been described in detail in the above embodiments, and therefore, is not described herein again.

In the method provided by the embodiment of the invention, after receiving the 18X message and the switching detection completion message, the MSCS can directly send the SRVCC switching completion notification message, that is, the MSCS is not limited by the time sequence of the network element message in the IMS, and does not need to wait for the INFO message of the IMS all the time, so that the success rate of SRVCC switching can be improved to a great extent.

S309, MSCS returns switching detection completion response message to target base station;

s310, the MME returns an SRVCC completion notification response message to the MSCS.

S311, MSCS sends PRACK message to IMS, the PRACK message is the confirmation request message to the 18X message in S306;

s312, the IMS returns 200OK information to the MSCS, the 200OK information is the response information to the 18X information in S306;

s313, MSCS receives INFO message sent by IMS; after receiving the INFO message returned by the IMS, the MSCS can normally process the current call, i.e., establish the SRVCC service.

It should be noted that in this embodiment, S308, S309, and S313 do not have a specific sequence, and may be executed sequentially or simultaneously.

Fig. 11 is a schematic structural diagram of a switching apparatus of SRVCC according to an embodiment of the present invention. The SRVCC handover apparatus provided in this embodiment is applicable to a case where SRVCC handover is performed when the UE moves from a 4G network to a 2G/3G network, and the SRVCC handover apparatus is implemented by combining hardware and software, and the apparatus may be integrated in a processor of an MSCS for the processor to call. As shown in fig. 11, the switching device of SRVCC of this embodiment may include: a transmitting module 11 and a receiving module 12.

The sending module 11 is configured to send an SIP establishment request message to the IMS according to the handover number acquired from the MME.

The switching device of SRVCC provided by the embodiment of the invention solves the problem of how to improve the success rate of SRVCC switching in the process of executing SRVCC switching when UE moves from a 4G network to a 2G/3G network. As shown in fig. 1, because the MME is configured to perform UE reachability management, when the UE moves from a 4G network to a 2G/3G network, the MME sends an SRVCC handover request message to the MSCS, and the message carries a handover number to be SRVCC handed over, the sending module 11 may send an SIP establishment request message to the IMS according to the handover number acquired from the MME.

A receiving module 12, configured to receive an update media message sent by an IMS and a handover detection completion message sent by a target base station;

the sending module 11 is further configured to send an SRVCC handover complete notification message to the MME after the receiving module 12 receives the update media message and the handover detection complete message.

In the embodiment of the present invention, the sending module 11 sends the SRVCC handover complete notification message to the MME at a different time from the time when the MSCS sends the SRVCC handover complete notification message in the prior art, and specifically, after the receiving module 12 receives the update media message sent by the IMS and the handover detection complete message sent by the target base station, the sending module 11 may immediately send the SRVCC handover complete notification message to the MME. According to the device provided by the embodiment of the invention, the MSCS does not need to wait for the INFO message returned by the IMS side, and the sending module 11 can directly send the SRVCC switching completion notification message to the MME, so that the phenomenon that the MME cannot receive the SRVCC switching completion notification message for a long time because the IMS does not return the INFO message for a long time after the sending module 11 sends the SIP establishment request message is avoided, and the SRVCC switching cancellation message is actively sent to the MSCS to notify the MSCS of call release.

The above embodiments have described the drawbacks and problems in the prior art in performing SRVCC handover, and therefore will not be described herein again. Compared with the technical scheme of executing SRVCC handover in the prior art, in the switching process of the SRVCC switching device provided by the embodiment of the invention, MSCS does not need to wait for an INFO message returned by IMS, and can send an SRVCC handover completion notification message to MME as long as an 18X message sent by IMS and a handover detection completion message sent by a target base station are received; it can be seen that, by optimizing the handover procedure at the MSCS side, the device provided in the embodiment of the present invention does not affect the early cancellation of the handover procedure even if the time for the IMS to return the INFO message is long, and achieves the purpose of ensuring that the MME does not overtime in advance, thereby ensuring the smooth completion of the handover procedure, improving the success rate of SRVCC handover, and accordingly, enhancing the user experience effect of the operator on MSCS products.

The SRVCC handover apparatus according to the embodiment of the present invention is configured to execute the SRVCC handover method according to the embodiment shown in fig. 4 of the present invention, and has corresponding functional modules, which have similar implementation principles and technical effects and are not described herein again.

Alternatively, in embodiments of the present invention,

the receiving module 12 is further configured to receive, before the sending module 11 sends the SIP setup request message to the IMS, an SRVCC handover request message sent by an MME, where the SRVCC handover request message includes a handover number and identification information of a target base station;

a sending module 11, configured to send a handover detection request message to the target base station according to the identifier information of the target base station received by the receiving module 12;

the receiving module 12 is further configured to receive a handover detection response message sent by the target base station, where the handover detection response message is used to indicate that the target base station has a capability of allocating radio resources.

In the embodiment of the present invention, it has been described above that the sending module 11 sends the SIP establishment request message according to the handover number acquired from the MME, and in practical applications, the way for the MSCS to acquire the handover number and the radio resource is as follows: when UE moves from 4G network to 2G/3G network, MME confirms target base station according to UE movement and sends SRVCC switching request message carrying switching number and identification information of target base station to MSCS, then MSCS interacts switching detection request message and switching detection response message with target base station according to the obtained message, and obtains that the target base station can distribute wireless resource from switching detection response message, namely has switching capability. In addition, the MSCS initiates a call back migration process according to the acquired switching number, namely, sends a SIP establishment request message to the IMS.

Further, as shown in fig. 12, a schematic structural diagram of another SRVCC handover apparatus according to an embodiment of the present invention is provided. On the basis of the structure of the apparatus shown in fig. 11, the apparatus provided in this embodiment may further include:

a calculating module 13, configured to calculate a success rate of SRVCC handover according to the number of times that the sending module 11 sends the notification message of SRVCC handover completion and the number of times that the receiving module 12 receives the request message of SRVCC handover.

It should be noted that, in the apparatus provided in the embodiment of the present invention, the steps performed by the sending module 11 and the receiving module 12 may be repeatedly performed, and the steps are performed as long as the condition that the UE moves from the 4G network to the 2G/3G network is satisfied. Therefore, the calculating module 13 may calculate the SRVCC handover success rate in a certain preset time period according to the number of times of sending the SRVCC handover completion notification message and the number of times of receiving the SRVCC handover request message.

The SRVCC handover apparatus according to the embodiment of the present invention is configured to execute the SRVCC handover method according to the embodiment shown in fig. 5 of the present invention, and has corresponding functional modules, which have similar implementation principles and technical effects and are not described herein again.

Optionally, as shown in fig. 13, a schematic structural diagram of a further SRVCC handover apparatus according to an embodiment of the present invention is provided. On the basis of the structure of the apparatus shown in fig. 11, the MSCS of this embodiment may be provided with a timer, and the apparatus provided in this embodiment may further include:

a starting module 14, configured to start a timer after the sending module 11 sends the SIP establishment request message to the IMS;

the sending module 11 is further configured to send a notification message for canceling SRVCC handover to the MME when the timer reaches a preset time and does not receive the INFO message sent by the IMS.

In the embodiment of the present invention, a certain time may be reserved on the MSCS side to wait for the INFO message returned by the IMS, that is, after the sending module 11 sends the SIP establishment request message, the timer may be started to wait for the INFO message returned by the subsequent IMS by setting the timer in the MSCS, and if the INFO message is not received within the preset time, the sending module 11 may actively send a notification message to cancel SRVCC handover to the MME, so as to release the current call.

Further, the apparatus provided in this embodiment may also include:

the calculating module 13, and a manner of calculating the SRVCC handover success rate by the calculating module 13 may be: and calculating the success rate of the SRVCC handover according to the times of sending the SRVCC handover completion notification message by the sending module 11, the times of receiving the SRVCC handover request message by the receiving module 12, and the times of sending the SRVCC handover cancel notification message by the sending module 11. In practical application, the calculation formula of the SRVCC handover success rate may be:

The SRVCC handover apparatus according to the embodiment of the present invention is configured to execute the SRVCC handover method according to the embodiment shown in fig. 6 of the present invention, and has corresponding functional modules, which have similar implementation principles and technical effects, and are not described herein again.

In practical applications, the sending module 11 and the receiving module 12 in the embodiments shown in fig. 11 to fig. 13 of the present invention may be implemented by a transceiver of an MSCS, and the calculating module 13 and the starting module 14 may be implemented by a processor of the MSCS, where the processor may be, for example, a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more Integrated circuits that implement the embodiments of the present invention.

Fig. 14 is a schematic structural diagram of a switching apparatus of SRVCC according to another embodiment of the present invention. The SRVCC handover apparatus provided in this embodiment is applicable to a case where SRVCC handover is performed when the UE moves from a 4G network to a 2G/3G network, and the SRVCC handover apparatus is implemented by combining hardware and software, and the apparatus may be integrated in a processor of an MME for the processor to call. As shown in fig. 14, the switching device of SRVCC of this embodiment may include: a transmitting module 21 and a receiving module 22.

Wherein, the sending module 21 is configured to send an SRVCC handover request message to the MSCS.

The switching device of SRVCC provided by the embodiment of the invention is a mode for solving how to improve the success rate of SRVCC switching in the process of executing SRVCC switching when UE moves from a 4G network to a 2G/3G network. As shown in fig. 1, because the MME is configured to perform UE reachability management, when the UE moves from a 4G network to a 2G/3G network, the sending module 21 of the MME may send an SRVCC handover request message to the MSCS, and the message carries a handover number to be SRVCC handed over, so that the MSCS may send an SIP establishment request message to the IMS according to the handover number acquired from the MME.

A receiving module 22, configured to receive an SRVCC handover complete notification message sent by the MSCS, where the SRVCC handover complete notification message is sent by the MSCS to the MME after receiving an update media message sent by the information management system IMS and a handover detection complete message sent by the target base station.

In the embodiment of the present invention, the time when the MSCS sends the SRVCC handover complete notification message to the MME is different from the time when the MSCS sends the SRVCC handover complete notification message in the prior art, and specifically, after receiving the update media message sent by the IMS and the handover detection complete message sent by the target base station, the MSCS can immediately send the SRVCC handover complete notification message to the MME. According to the device provided by the embodiment of the invention, the MSCS can directly send the SRVCC switching completion notification message to the MME without waiting for the INFO message returned by the IMS side, and the receiving module 22 of the MME can receive the SRVCC switching completion notification message in a short time, so that the phenomenon that the IMS does not return the INFO message for a long time after the MSCS sends the SIP establishment request message, the MME cannot receive the SRVCC switching completion notification message for a long time, and the SRVCC switching cancellation message is actively sent to the MSCS to notify the MSCS to release the call is avoided.

The above embodiments have described the drawbacks and problems in the prior art in performing SRVCC handover, and therefore will not be described herein again. Compared with the technical scheme of executing SRVCC handover in the prior art, in the switching process of the SRVCC switching device provided by the embodiment of the invention, MSCS does not need to wait for an INFO message returned by IMS, and can send an SRVCC handover completion notification message to MME as long as an 18X message sent by IMS and a handover detection completion message sent by a target base station are received; it can be seen that, according to the technical scheme provided by the embodiment of the present invention, by optimizing the handover procedure on the MSCS side, even if the time for the IMS to return the INFO message is long, the advanced cancellation of the handover procedure is not affected, and it is achieved that it is ensured that the MME does not time out in advance, thereby ensuring the smooth completion of the handover procedure, and improving the success rate of SRVCC handover, and accordingly, enhancing the user experience effect of the operator on MSCS products.

The SRVCC handover apparatus according to the embodiment of the present invention is used to execute the SRVCC handover method according to the embodiment of fig. 7 of the present invention, and has corresponding functional modules, which have similar implementation principles and technical effects and are not described herein again.

In this embodiment of the present invention, the SRVCC handover request message sent by the sending module 21 includes identification information of a target base station, where the SRVCC handover request message is used to instruct the MSCS to send a handover detection request message to the target base station according to the identification information of the target base station, and receive a handover detection response message sent by the target base station, and the handover detection response message is used to instruct the target base station to have a capability of allocating radio resources. That is to say, after acquiring the identification information of the target base station by receiving the SRVCC handover request message, the MSCS may interact the handover detection request message and the handover detection response message with the target base station according to the identification information of the target base station, and learn from the handover detection response message that the base station can perform the allocation of radio resources, that is, has the handover capability.

In this embodiment of the present invention, the SRVCC handover request message sent by the sending module 21 may further include a handover number, and the SRVCC handover request message is further used to instruct the MSCS to send a session initiation protocol SIP establishment request message to the IMS according to the handover number. That is, after acquiring the handover number by receiving the SRVCC handover request message, the MSCS may send the SIP establishment request message to the IMS according to the handover number. In practical application, the way for the MSCS to acquire the handover number and radio resources is: when UE moves from 4G network to 2G/3G network, MME confirms target base station according to UE movement and sends SRVCC switching request message carrying switching number and identification information of target base station to MSCS, then MSCS carries out interaction of switching detection request message and switching detection response message with target base station according to the obtained message, and obtains wireless resource distributed for switching number by target base station from switching detection response message. In addition, the MSCS initiates a call-back migration process according to the switching number acquired from the SRVCC switching request message, namely, sends an SIP establishment request message to the IMS.

Optionally, fig. 15 is a schematic structural diagram of a handover apparatus of SRVCC according to an embodiment of the present invention. On the basis of the structure of the apparatus shown in fig. 14, the apparatus provided in this embodiment may further include:

the calculating module 23 is configured to calculate a success rate of SRVCC handover according to the number of times that the receiving module 22 receives the SRVCC handover complete notification message and the number of times that the sending module 21 sends the SRVCC handover request message.

It should be noted that, in the apparatus provided in the embodiment of the present invention, the steps performed by the sending module 21 and the receiving module 22 and the steps performed by the MSCS side may be repeatedly performed, as long as the condition that the UE moves from the 4G network to the 2G/3G network is satisfied, the sending module 21 and the receiving module 22 perform the steps, and the MSCS performs the corresponding steps. Therefore, the calculating module 23 of the MME may calculate, within a certain preset time period, the SRVCC handover success rate within the time period according to the number of times of receiving the SRVCC handover completion notification message and the number of times of sending the SRVCC handover request message.

In the technical scheme provided by the embodiment of the invention, the MSCS can send the SRVCC switching completion notification message to the MME without waiting for the INFO message returned by the IMS, thereby improving the SRVCC switching success rate to a certain extent.

The SRVCC handover apparatus according to the embodiment of the present invention is configured to execute the SRVCC handover method according to the embodiment shown in fig. 8 of the present invention, and has corresponding functional modules, which have similar implementation principles and technical effects and are not described herein again.

Alternatively, in the handover apparatus of SRVCC shown in fig. 15,

the receiving module 22 is further configured to receive a notification message for canceling SRVCC handover, which is sent by the MSCS;

the calculating module 23 is further configured to calculate a success rate of the SRVCC handover according to the number of times that the receiving module 22 receives the SRVCC handover complete notification message, the number of times that the sending module 21 sends the SRVCC handover request message, and the number of times that the receiving module 22 receives the notification message for canceling the SRVCC handover.

In the embodiment of the present invention, a certain time may also be reserved on the MSCS side to wait for the INFO message returned by the IMS, that is, the timer may be started to wait for the INFO message returned by the subsequent IMS in a manner that the MSCS is provided with the timer after the MSCS sends the SIP establishment request message to the IMS, and if the INFO message is not received within the preset time, the MSCS may actively send a cancel SRVCC handover notification message to the MME to release the current call. Therefore, in this embodiment of the present invention, after receiving the SRVCC handover complete notification message, the receiving module 22 of the MME may also receive a notification message for canceling SRVCC handover for releasing the current call.

The formula for calculating the SRVCC handover success rate by the calculation module 23 in this embodiment may also be:

The SRVCC handover apparatus according to the embodiment of the present invention is configured to execute the SRVCC handover method according to the embodiment shown in fig. 9 of the present invention, and has corresponding functional modules, which have similar implementation principles and technical effects and are not described herein again.

In practical applications, the sending module 21 and the receiving module 22 in the embodiments shown in fig. 14 to fig. 15 of the present invention may be implemented by a transceiver of an MSCS, and the calculating module 23 may be implemented by a processor of the MSCS, where the processor may be, for example, a CPU, an ASIC, or one or more integrated circuits that implement the embodiments of the present invention.

It will be understood by those skilled in the art that all or part of the steps of the above methods may be implemented by a program instructing associated hardware (e.g., a processor) which may be stored in a computer readable storage medium such as a read only memory, a magnetic or optical disk, etc. Alternatively, all or part of the steps of the above embodiments may be implemented using one or more integrated circuits. Accordingly, the modules/units in the above embodiments may be implemented in hardware, for example, by an integrated circuit, or may be implemented in software, for example, by a processor executing programs/instructions stored in a memory to implement the corresponding functions. Embodiments of the invention are not limited to any specific form of hardware or software combination.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for switching a single-channel continuous service is characterized by comprising the following steps:

and after receiving the update media message sent by the IMS and the switching detection completion message sent by the target base station, the MSCS immediately sends a single-channel continuous service SRVCC switching completion notification message to the MME.

2. The method of claim 1, wherein before the MSCS sends the SIP setup request message to the IMS, the method comprises:

3. The method for switching the single-channel continuous service according to claim 2, wherein the method further comprises:

4. The method of claim 2, wherein a timer is set in the MSCS, and after the MSCS sends the SIP setup request message to the IMS, the method further comprises:

the MSCS starts the timer;

5. The method for switching the single-channel continuous service according to claim 4, wherein the method further comprises:

6. A method for switching a single-channel continuous service is characterized by comprising the following steps:

and the MME receives an SRVCC switching completion notification message sent by the MSCS, wherein the SRVCC switching completion notification message is sent to the MME immediately after the MSCS receives an update media message sent by an Information Management System (IMS) and a switching detection completion message sent by a target base station.

7. The method of claim 6, wherein the SRVCC handover request message includes identification information of a target base station, and wherein the SRVCC handover request message is used to instruct the MSCS to send a handover detection request message to the target base station according to the identification information of the target base station, and receive a handover detection response message sent by the target base station, and wherein the handover detection response message is used to instruct the target base station to have a capability of allocating radio resources.

8. The method of claim 6, wherein the SRVCC handover request message includes a handover number, and the SRVCC handover request message is used to instruct the MSCS to send a session initiation protocol, SIP, establishment request message to the IMS according to the handover number.

9. The method for switching the single-channel continuous service according to any one of claims 6 to 8, wherein the method further comprises:

10. The method for switching the single-channel continuous service according to any one of claims 6 to 8, wherein the method further comprises:

11. A switching device for single-channel continuous service, wherein the device is disposed in a mobile interaction center server MSCS, the device comprising:

the sending module is further configured to send a single-channel continuous service SRVCC handover complete notification message to the MME immediately after the receiving module receives the update media message and the handover detection complete message.

12. The apparatus for switching a single-channel continuous service according to claim 11, wherein the receiving module is further configured to receive an SRVCC handover request message sent by the MME before the sending module sends an SIP setup request message to the IMS, where the SRVCC handover request message includes the handover number and the identification information of the target base station;

13. The apparatus for switching the single-channel continuous service according to claim 12, wherein the apparatus further comprises:

14. The apparatus for switching the single-channel continuous service according to claim 12, wherein a timer is provided in the MSCS, the apparatus further comprising:

15. The apparatus for switching the single channel continuous service according to claim 14, wherein the apparatus further comprises:

16. An apparatus for switching a single-channel continuous service, the apparatus being disposed in a mobility management entity MME, the apparatus comprising:

a receiving module, configured to receive an SRVCC handover complete notification message sent by the MSCS, where the SRVCC handover complete notification message is sent by the MSCS to the MME immediately after receiving an update media message sent by an information management system IMS and a handover detection complete message sent by a target base station.

17. The apparatus of claim 16, wherein the SRVCC handover request message includes identification information of a target base station, and wherein the SRVCC handover request message is configured to instruct the MSCS to send a handover detection request message to the target base station according to the identification information of the target base station, and receive a handover detection response message sent by the target base station, and wherein the handover detection response message is configured to instruct the target base station to have a capability of allocating radio resources.

18. The apparatus of claim 16, wherein the SRVCC handover request message includes a handover number, and wherein the SRVCC handover request message is configured to instruct the MSCS to send a session initiation protocol, SIP, setup request message to the IMS according to the handover number.

19. The apparatus for switching the single channel continuous service according to any one of claims 16 to 18, wherein the apparatus further comprises:

20. The apparatus for switching a single channel continuous service according to any one of claims 16 to 18, wherein the receiving module is further configured to receive a cancel SRVCC handover notification message sent by the MSCS;

the device further comprises: