CN101442801B - Method and device for network registration - Google Patents

Abstract

The embodiment of the invention discloses a method and equipment for network registry. The method comprises following steps: receiving registry request from IMS terminal; transmitting position updating request to MSC; receiving position updating response from the MSC; transmitting registry success response to IMS terminal. The embodiment of the invention provides complete technical scheme and implements registry of IMS terminal to mobile core network thereby IMS terminal can use service provided by mobile core network and can be integrally managed by mobile core network.

Description

Method and device for network registration

technical field

The invention relates to the field of communication technology, in particular to a method and device for network registration.

Background technique

IMS (Internet Protocol Multimedia Subsystem, Internet Protocol Multimedia Subsystem) is a network environment based on IP (Internet Protocol, Internet Protocol), with open services and has nothing to do with access methods. It provides user identification authentication, Basic capabilities such as QOS (Quality of Service) assurance and security assurance provide strong support for various businesses. At present, services such as multimedia telephony, conferencing, games, etc. are running based on the IMS network. With the active deployment of IMS, more IMS-based services will be put into operation.

GAN (Generic Access Network, Universal Access Network) is a technology defined by 3GPP (3rd Generation Partnership Project, Third Generation Partnership Project), which enables mobile terminals or non-mobile terminals to access the mobile core network through a common IP, Thereby expanding the range of terminals of the mobile core network.

In the process of realizing the present invention, the inventor finds that there are following shortcomings in the prior art:

In the prior art, there is no technical solution to support the registration of the IMS terminal to the mobile core network, and the IMS terminal cannot use services provided by the mobile core network.

Contents of the invention

The embodiment of the present invention provides a method and device for network registration, which realize the registration of an IMS terminal to a mobile core network.

The embodiment of the present invention provides a method for network registration, including the following steps:

The mobile switching center MSC configures the Internet Protocol Multimedia Subsystem IMS domain as a circuit domain CS domain system, the IMS network becomes an access network of the CS domain, and the general access network controller application server GANC AS is controlled through the Mc interface A media gateway MGW realizes the conversion of the user plane;

The GANC AS receives a registration request from an IMS terminal;

The GANC AS sends a location update request to MSC (Mobile Switching Centre, Mobile Switching Center) according to the registration request;

The GANC AS receives a location update response from the MSC;

The GANC AS sends a registration success response to the IMS terminal.

An embodiment of the present invention provides a device for network registration, including a receiving module and a sending module:

The receiving module is configured to configure the Internet Protocol Multimedia Subsystem IMS domain as a circuit domain CS domain system when the mobile switching center MSC, the IMS network becomes an access network of the CS domain, and the universal access network controller After the application server GANC AS controls a media gateway MGW through the Mc interface to realize the conversion of the user plane, it receives the registration request from the IMS terminal and receives the location update response from the MSC;

The sending module is configured to send a location update request to the MSC according to the registration request received by the receiving module, and send a registration success response to the IMS terminal.

In the embodiment of the present invention, by providing a complete technical solution, the registration of the IMS terminal to the mobile core network is realized, so that the IMS terminal can use the services provided by the mobile core network, and can be uniformly managed by the mobile core network.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a kind of network system architecture diagram in the embodiment of the present invention

Fig. 2 is a flow chart of a method for network registration in an embodiment of the present invention;

3 is a flowchart of a method for registering an IMS terminal to a mobile core network in an embodiment of the present invention;

FIG. 4 is a flowchart of a method for switching an IMS terminal from an IMS domain to a CS domain in an embodiment of the present invention;

FIG. 5 is a flowchart of a method for switching an IMS terminal from a CS domain to an IMS domain in an embodiment of the present invention;

Fig. 6 is a structural diagram of a device for implementing network registration in an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

The embodiment of the present invention is applied in the system architecture shown in Figure 1. In this architecture, the IMS network becomes an access network of CS (Circuit Switched domain, circuit domain). Since the user plane of IMS is based on RTP (Real- Time Transport Protocol, real-time transport protocol) media stream, and the A interface is the circuit domain media stream bearer, GANC (Generic Access Network Control, general access network controller) AS (Application Server, application server) controls a The MGW (Media Gateway, media gateway) realizes the conversion of the user plane.

The terminal in this system can be a common IMS SIP (Session Initiated Protocol, Session Initiated Protocol) Phone, or an IMS Phone that has been enhanced to support the switching function between the IMS domain and the mobile CS domain, that is, the enhanced IMS terminal.

The MSC configures the IMS domain as a CS domain system. Like the configuration of a common CS domain system, the configuration data includes information such as one or more virtual LAIs (Location Area Identity) under the control of the IMS domain.

The embodiment of the present invention provides a method for network registration, as shown in Figure 2, including the following steps:

Step 201, GANC AS receives a registration request from an IMS terminal.

Step 202, the GANC AS sends a location update request to the MSC according to the registration request.

Wherein, in step 202, after the GANC AS sends a location update request to the MSC according to the registration request, it may also include:

GANC AS receives the authentication request from MSC;

GANC AS calculates the authentication response according to the configured algorithm;

GANC AS sends an authentication response to MSC.

Wherein, in step 202, after the GANC AS sends a location update request to the MSC according to the registration request, it may also include:

GANC AS receives encryption request from MSC;

GANC AS sends an encrypted response to MSC.

Wherein, in step 202, after the GANC AS sends a location update request to the MSC according to the registration request, it may also include:

GANC AS receives and records TMSI from MSC.

Step 203, the GANC AS receives the location update response from the MSC.

Step 204, the GANC AS sends a registration success response to the IMS terminal.

Wherein, if in step 202, after the GANC AS sends the location update request to the MSC according to the registration request, it also includes:

GANC AS receives and records TMSI from MSC

Then in step 204, after the GANC AS sends the registration success response to the IMS terminal, it may also include:

The GANC AS sends a TMSI reallocation complete message to the MSC.

Wherein, in step 204, after the GANC AS sends the registration success response to the IMS terminal, it may also include:

The GANC AS sends the system information of the virtual cell to the IMS terminal. The system information may include one or more of the following parameters: location area identifier of the virtual cell, transmission code, signal reception strength, signal reception quality, base station identification code, and broadcast control channel frequency.

Wherein, in step 204, after the GANC AS sends the registration success response to the IMS terminal, it may also include:

GANC AS receives the measurement report from the IMS terminal;

GANC AS sends a handover request to MSC according to the measurement report, and the handover request carries target cell information;

The GANC AS receives the handover command from the MSC, and the handover command carries the target cell information;

The GANC AS sends a switching command to the IMS terminal, so that the IMS terminal switches into the CS domain.

Wherein, after the GANC AS sends the switching command to the IMS terminal, it may also include:

GANC AS receives the resource release message from MSC;

The GANC AS releases the resources occupied by the IMS terminal according to the resource release message.

Wherein, in step 204, after the GANC AS sends the registration success response message to the IMS terminal, it may also include:

GANC AS receives the handover request message from MSC;

GANC AS sends a handover request response message to MSC;

The GANC AS receives the switching call message from the IMS terminal;

The GANC AS sends a handover call response message to the IMS terminal, so that the IMS terminal switches into the IMS domain.

Wherein, after the GANC AS sends the switching call response message to the IMS terminal, it also includes:

The GANC AS sends a handover completion message to the MSC, so that the MSC sends an instruction to release resources to the source BSC or RNC according to the handover completion message.

Wherein, after the GANC AS sends the handover request response message to the MSC, it may also include:

The MSC sends a handover command to the source BSC or RNC, and the handover command carries the virtual cell ID of the IMS domain;

The source BSC or RNC sends the handover command to the IMS terminal.

In the embodiment of the present invention, by providing a complete technical solution, the registration of the IMS terminal to the mobile core network and the handover of the IMS terminal between the CS domain and the IMS domain are realized, so that the IMS terminal can use the services provided by the mobile core network, Moreover, the mobile core network can perform unified management, and the IMS terminal can be handed over to a cell with a more suitable working environment across domains, thereby improving the working performance of the IMS terminal.

The embodiment of the present invention provides a method for registering an IMS terminal to a mobile core network, as shown in FIG. 3 , including the following steps:

In step 301, the IMS terminal performs registration and authentication in the IMS domain.

Step 302, the S-CSCF (Serving Call Session Control Function, serving call session control function entity) of the IMS domain triggers the registration of the IMS terminal to the GANC AS.

Step 303, the S-CSCF forwards the SIP registration request to the GANC AS.

Step 304, the GANC AS obtains the IMSI (international mobile subscriber identity, International Mobile Subscriber Identity) information of the IMS terminal in the CS domain according to the attribute data of the IMS terminal, simulates a mobile terminal by the IMS terminal, and sends a location update request to the MSC ( Location Update Request), the LAI attached to this message can be obtained from the P-Access-Network-Info of the registration request, or the virtual LAI locally configured by the GANC AS.

Step 305, the MSC starts the network authentication process, and the MSC sends an authentication request (Authentication Request) to the GANC AS, and the request message carries the random value of this authentication, such as the RAND parameter or the AUTN parameter.

Step 306, in order to be compatible with various SIP Phones, the GANC AS cannot allow the SIP terminal to directly participate in the authentication process. Therefore, the private information and authentication algorithm type for user authentication are configured in the GANC AS, and the corresponding 2G/ 3G corresponding authentication algorithm, etc. GANC AS uses these information, as well as parameters such as RAND and AUTN carried in the authentication request, to calculate the authentication response instead of the user.

Step 307, after calculating the authentication response, the GANC AS returns an authentication response (Authentication Response) message to the MSC.

Step 308, the MSC may instruct the GANC AS to perform the encryption process, and send a Ciphering Request to the GANC AS.

Step 309, because the encryption of the mobile network is limited to the air interface, and the IMS-Based GANC system has no real air interface, so the IMS-Based GANC AS simply replies with an encrypted response.

In step 310, the MSC may initiate a TMSI (Temperate Mobile Subscriber Identity, Temporary Mobile Identity) reallocation message to the GANC AS to allocate a TMSI to the IMS terminal.

Step 311, the MSC completes the location update process, and returns a location update response message to the GANC AS.

In step 312, the GANC AS returns 200 OK to the S-CSCF.

Step 313, if the TMSI reallocation process is detected in the 310th step or the 311st step, then the GANC AS records the TMSI for the IMS terminal that initiated the registration, and if the GANC AS has the previous TMSI record of the IMS terminal that initiated the registration, then use the new The TMSI covers the old TMSI. If the GANC AS has a record of other IMS terminals using the TMSI, the record will be cleared.

Step 314, if the aforementioned process includes the TMSI reallocation process, the GANC AS returns a TMSI reallocation complete (TMSI Reallocation Complete) message to the MSC.

Step 315, in order to support the enhanced IMS terminal to realize handover between the IMS domain and the CS domain, the GANCAS may send a system-related message to the S-CSCF, instructing the GANC AS to simulate the system information of the cell. System information may include: location area identification, transmission code, signal reception strength, signal reception quality, base station identification code, broadcast control channel frequency and other information; location area identification/transmission code can be configured locally in GANC AS, or can be obtained from the registration message Obtained from P-Access-Network-Info. These system information are transmitted through SIP messages, such as MESSAGE messages. It may actively send a request to GANC AS to obtain these system information after successful registration. Considering that SIP transactions may fail, such as message retransmission failures, etc., GANC AS may resend system information after a period of time after receiving the "408 Request Timeout" failure response; if the failure response is still received, it will stop the IMS The terminal sends system information.

Step 316, the S-CSCF sends the system-related message to the IMS terminal.

In step 317, the IMS terminal returns a successful response of the system-related message to the S-CSCF.

Step 318, S-CSCF sends the success response to GANC AS.

In the embodiment of the present invention, by providing a complete technical solution, the registration of the IMS terminal to the core network is realized, so that the IMS terminal can use the service provided by the mobile core network, and can be uniformly managed by the mobile core network.

An embodiment of the present invention provides a handover method for an IMS terminal from an IMS domain to a CS domain, as shown in FIG. 4 , including the following steps:

Step 401, the IMS terminal has completed the registration to the mobile core network, the IMS terminal continuously detects the signal of the surrounding CS network, and periodically sends the measurement report of the adjacent cell to the GANC AS through the SIP message, and the measurement report includes the virtual cell of the GANC AS And the signal reception strength, signal reception quality, base station identification code, broadcast control channel frequency and discontinuous transmission information of the six strongest neighboring cells, which are encapsulated in the message body or header field of the SIP message.

In step 402, the GANC AS locally configures values such as signal reception strength and signal reception quality of the virtual cell for handover judgment. When the GANC AS judges from the measurement report that the surrounding cells are more suitable for calls, the GANC AS sends a handover request (Handover Required) to the MSC through the A interface.

In step 403, the MSC initiates a handover request to the BSC (Base Station Controller, base station controller) or RNC (Radio Network Controller, radio network controller) to which the handover target cell belongs.

Step 404, the MSC sends a handover command (Handover Command) to the GANC AS to instruct the GANC AS to handover the IMS terminal to the target cell, and the request includes the information of the target cell to be handed over.

Step 405, the GANC AS carries the switching command through the SIP message, and sends the switching command to the IMS terminal.

Step 406, the IMS terminal returns a switching response to the GANC AS.

In step 407, the IMS terminal completes the switching operation of accessing the CS domain.

Step 408, the BSC or RNC to which the handover target cell belongs sends a handover completion indication to the MSC, and at this time the IMS terminal starts to send and receive media streams through the CS network.

In step 409, the MSC sends a Clear Command message to the GANC AS to instruct the GANC AS to release the relevant resources occupied by the IMS terminal in the IMS domain.

Step 410, the GANC AS starts to release the SIP session established by the IMS terminal in the IMS, and sends a release request to the IMS terminal.

In step 411, the IMS terminal returns a release response to the GANC AS, and the SIP session is released.

In step 412, the GANC AS returns a Clear Complete message to the MSC.

Step 413, the GANC AS releases the media channel of the MGW occupied by the IMS terminal through the Mc interface.

In the embodiment of the present invention, by providing a complete technical solution, the handover of the IMS terminal from the IMS domain to the CS domain is realized, so that the IMS terminal can be handed over to a cell with a more suitable working environment across domains, and the working performance of the IMS terminal is improved.

The embodiment of the present invention provides a method for switching an IMS terminal from a CS domain to an IMS domain, as shown in FIG. 5 , including the following steps:

Step 501, the IMS terminal in the CS domain continuously detects the signals of the surrounding CS wireless network and the wireless signal of the IP access network of the IMS. If the wireless signal strength and quality of the IP access network are appropriate, the IMS terminal will register with the mobile core network in the IMS domain corresponding to the wireless signal of the IP access network. During the registration process, the GANC AS sends the terminal the information of its virtual cell Information, including the signal strength and quality of the virtual cell.

Step 502, the enhanced terminal periodically sends a measurement report to the BSC or RNC currently accessing the CS domain cell, and the measurement report includes the signal reception strength, signal reception quality, base station identification code, broadcast control channel frequency and discontinuity of the GANC AS virtual cell transfer information, etc.

Step 503, the BSC or RNC to which the current CS domain cell belongs decides to handover the call to the GANCAS virtual cell, and sends a handover request (Handover Required) to the MSC to instruct the MSC to initiate a handover to the GANCAS virtual cell.

In step 504, the MSC sends a handover request to the GANC AS, instructing the GANC AS to prepare for handover.

Step 505, the GANC AS returns a handover response message.

Step 506, the MSC sends a handover command (HandoverCommand) to the BSC or RNC to which the current CS domain cell belongs to instruct the IMS terminal to handover the call to the target cell, and the request includes the virtual cell ID of the GANC AS.

Step 507, the BSC or RNC to which the current CS domain cell belongs sends a handover command to the IMS terminal.

In step 508, the IMS terminal starts to send a handover call on the IMS network, and the destination address of the handover request is a handover PSI.

Step 509, the S-CSCF routes the handover call to the GANC AS corresponding to the PSI.

In step 510, the GANC AS starts to apply for a media channel from the MGW media through the Mc interface.

Step 511, the GANC AS sends a handover detection (Handover Detect) message to the MSC to indicate the start of handover.

In step 512, the GANC AS returns a "200 OK" response to the S-CSCF to accept the handover request. The SDP message is attached to the response, and the SDP message indicates information such as the receiving IP address and port of the media channel of the MGW.

In step 513, the S-CSCF forwards the "200 OK" response to the enhanced IMS terminal.

Step 514, the terminal returns "ACK" to the S-CSCF.

Step 515, "ACK" is forwarded to the GANC AS by the S-CSCF.

In step 516, the GANC AS sends a handover complete (Handover Complete) message to the MSC to indicate that the handover is complete, and at this time the enhanced IMS terminal starts to send media streams through the IMS network.

In step 517, the MSC sends a Clear Command to the source BSC or RNC to instruct it to release the resources occupied by the IMS terminal.

Step 518, the source BSC or RNC releases the radio resources occupied by the IMS terminal, and returns a clear complete (Clear Complete) message.

In the embodiment of the present invention, by providing a complete technical solution, the handover of the IMS terminal from the CS domain to the IMS domain is realized, so that the IMS terminal can be handed over to a cell with a more suitable working environment across domains, and the working performance of the IMS terminal is improved.

An embodiment of the present invention provides a device for realizing network registration, as shown in FIG. 6 , including a receiving module 601 and a sending module 602:

The receiving module 601 is configured to receive a registration request from an IMS terminal, and receive a location update response from an MSC;

The sending module 602 is configured to send a location update request to the MSC according to the registration request received by the receiving module 601, and send a registration success response to the IMS terminal.

Wherein, an authentication response calculation module 603 is also included,

An authentication response calculation module 603, configured to calculate an authentication response according to a configured algorithm after the receiving module 601 receives the authentication request from the MSC;

Then the sending module 602 is further configured to send the authentication response calculated by the authentication response calculating module 603 to the MSC.

in,

The receiving module 601 is also configured to receive an encryption request from the MSC;

The sending module 602 is further configured to send an encrypted response to the MSC.

in,

The receiving module 601 is also used to receive and record the TMSI from the MSC;

The sending module 602 is further configured to send a TMSI reallocation complete message to the MSC.

in,

The sending module 602 is further configured to send the system information of the virtual cell to the IMS terminal. The system information may include one or more of the following parameters: location area identifier of the virtual cell, transmission code, signal reception strength, signal reception quality, base station identification code, and broadcast control channel frequency.

in,

The receiving module 601 is further configured to receive a measurement report from the IMS terminal, and receive a handover command from the MSC, where the handover command carries the target cell information;

The sending module 602 is further configured to send a handover request to the MSC according to the measurement report, where the handover request carries target cell information, and send the handover command to the IMS terminal, so that the IMS terminal switches into the CS domain.

Wherein, a resource release module 604 is also included,

The resource releasing module 604 is configured to release the resource occupied by the IMS terminal according to the resource releasing message received by the receiving module 601 after the receiving module 601 receives the resource releasing message from the MSC.

in,

The receiving module 601 is also configured to receive a handover request from the MSC, and receive a handover call from the IMS terminal;

The sending module 602 is further configured to send a handover request response to the MSC, and send a handover call response to the terminal, so that the IMS terminal is handed over into the IMS domain.

in,

The sending module 602 is further configured to send a handover completion message to the MSC, so that the MSC sends an instruction to release resources to the source BSC or RNC according to the handover completion message.

Wherein, the device for implementing network registration may be GANC AS.

In the embodiment of the present invention, by providing a complete technical solution, the registration of the IMS terminal to the mobile core network and the handover of the IMS terminal between the CS domain and the IMS domain are realized, so that the IMS terminal can use the services provided by the mobile core network, Moreover, the mobile core network can perform unified management, and the IMS terminal can be handed over to a cell with a more suitable working environment across domains, thereby improving the working performance of the IMS terminal.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be realized by hardware, or by means of software plus a necessary general-purpose hardware platform. Based on this understanding, the technology of the present invention The solution can be embodied in the form of software products, which can be stored in a non-volatile storage medium (which can be CD-ROM, U disk, mobile hard disk, etc.), and include several instructions to make a computer device (It may be a personal computer, a server, or a network device, etc.) executes the methods described in various embodiments of the present invention.

In a word, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (19)

1. A method for network registration, characterized in that, comprising the following steps: The mobile switching center MSC configures the Internet Protocol Multimedia Subsystem IMS domain as a circuit domain CS domain system, the IMS network becomes an access network of the CS domain, and the general access network controller application server GANC AS is controlled through the Mc interface A media gateway MGW realizes the conversion of the user plane; The GANC AS receives a registration request from an Internet Protocol Multimedia Subsystem IMS terminal; The GANC AS sends a location update request to the mobile switching center MSC according to the registration request; The GANC AS receives a location update response from the MSC; The GANC AS sends a registration success response to the IMS terminal. 2. The method according to claim 1, wherein, after the GANC AS sends a location update request to the MSC according to the registration request, it also includes: The GANC AS receives an authentication request from the MSC; The GANC AS calculates the authentication response according to the configured algorithm; The GANC AS sends the authentication response to the MSC. 3. The method according to claim 1, wherein, after the GANC AS sends a location update request to the MSC according to the registration request, it also includes: The GANC AS receives an encryption request from the MSC; The GANC AS sends an encrypted response to the MSC. 4. The method according to claim 1, wherein, after the GANC AS sends a location update request to the MSC according to the registration request, it also includes: The GANC AS receives and records the Temporary Mobile Identity TMSI from the MSC; After the GANC AS sends a successful registration response to the terminal, it also includes: The GANC AS sends a TMSI reallocation complete message to the MSC. 5. The method according to claim 1, characterized in that, after the GANC AS sends a successful registration response to the IMS terminal, it further comprises: The GANC AS sends the system information of the virtual cell to the IMS terminal. the 6. The method according to claim 1, wherein, after the GANC AS sends a successful registration response to the IMS terminal, it further comprises: The GANC AS receives a measurement report from the IMS terminal; The GANC AS sends a handover request to the MSC according to the measurement report, and the handover request carries target cell information; The GANC AS receives a handover command from the MSC, and the handover command carries the target cell information; The GANC AS sends the switching command to the IMS terminal, so that the IMS terminal switches into the CS domain. 7. The method according to claim 6, characterized in that, after the GANC AS sends the switching command to the IMS terminal, further comprising: The GANC AS receives a resource release message from the MSC; The GANC AS releases the resource occupied by the IMS terminal according to the resource release message. 8. The method according to claim 1, characterized in that, after the GANC AS sends a successful registration response to the IMS terminal, further comprising: The GANC AS receives a handover request from the MSC; The GANC AS sends a handover response to the MSC; The GANC AS receives a handover call from the IMS terminal; The GANC AS sends a handover call response to the IMS terminal, so that the IMS terminal is switched into the IMS domain. 9. The method according to claim 8, characterized in that, after the GANCAS sends the switching call response to the IMS terminal, it further comprises: The GANC AS sends a handover completion message to the MSC, so that the MSC sends an instruction to release resources to the base station controller BSC or the radio network controller RNC according to the handover completion message. 10. The method according to claim 8, characterized in that, after the GANC AS sends the handover response to the MSC, further comprising: The MSC sends a handover command to the source BSC or RNC, and the handover command carries the virtual cell identifier of the IMS domain; The source BSC or RNC sends the handover command to the IMS terminal. 11. A device for realizing network registration, comprising a receiving module and a sending module: The receiving module is configured to configure the Internet Protocol Multimedia Subsystem IMS domain as a circuit domain CS domain system when the mobile switching center MSC, the IMS network becomes an access network of the CS domain, and the universal access network controller After the application server GANC AS controls a media gateway MGW through the Mc interface to realize the conversion of the user plane, it receives the registration request from the IMS terminal and receives the location update response from the MSC; The sending module is configured to send a location update request to the MSC according to the registration request received by the receiving module, and send a registration success response to the IMS terminal. 12. The device according to claim 11, further comprising an authentication response calculation module: The authentication response calculation module is configured to calculate an authentication response according to a configured algorithm after the receiving module receives the authentication request from the MSC; Then the sending module is further configured to send the authentication response calculated by the authentication response calculating module to the MSC. 13. The apparatus of claim 11 wherein, The receiving module is further configured to receive an encryption request from the MSC; The sending module is further configured to send an encrypted response to the MSC. 14. The apparatus of claim 11, wherein The receiving module is also used to receive and record the TMSI from the MSC; The sending module is further configured to send a TMSI reallocation complete message to the MSC. 15. The apparatus of claim 11, wherein The sending module is further configured to send the system information of the virtual cell to the IMS terminal. 16. The apparatus of claim 11, wherein The receiving module is further configured to receive a measurement report from the IMS terminal, and receive a handover command from the MSC, where the handover command carries target cell information; The sending module is further configured to send a handover request to the MSC according to the measurement report, the handover request carries target cell information, and sends the handover command to the IMS terminal, so that the IMS terminal is handed over into the CS domain. 17. The device according to claim 11, further comprising a resource release module: The resource release module is configured to, after the receiving module receives the resource release message from the MSC, release the resource occupied by the IMS terminal according to the resource release message received by the receiving module. 18. The apparatus of claim 11, wherein The receiving module is configured to receive a handover request from the MSC, and receive a handover call from the IMS terminal; The sending module is configured to send a handover request response to the MSC, and send a handover call response to the IMS terminal, so that the terminal is handed over into the IMS domain. 19. The apparatus of claim 18, wherein The sending module is further configured to send a handover completion message to the MSC, so that the MSC sends an instruction to release resources to the BSC or RNC according to the handover completion message. the

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