WO2012041139A1

WO2012041139A1 - Method and system for circuit switch domain call to access network through the visited ims

Info

Publication number: WO2012041139A1
Application number: PCT/CN2011/078861
Authority: WO
Inventors: 谢振华
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-09-27
Filing date: 2011-08-24
Publication date: 2012-04-05
Also published as: CN102420802A

Abstract

Disclosed is a method for a circuit switch (CS) domain call to access the network through the visited IP multimedia core network subsystem (IMS), comprising: a mobile switching center (MSC) or a user equipment (UE) requesting a visited IMS control point (VICP) information of a calling user from a service centralization and continuity application server (SCC AS), or obtaining the visited IMS control point (VICP) information according to the number or identifier of the calling user; the MSC or UE sending a call message via the VICP corresponding to the VICP information. Also disclosed is a system for the CS domain call to access the network through the visited IMS. The present invention can utilize the IMS access capabilities of the visited network when the UE initiates a call through the CS domain, thus reducing the consumption of CS long-distance link resources to a certain extent.

Description

Method and system for accessing circuit switched domain call through visited IMS access point

The present invention relates to a technology for accessing a CS (Circuit Switch) domain call through an access point of an IP Multimedia Core Subsystem (IMS), and more particularly to a circuit switched domain call being accessed through a visited IMS. Method and system for access point access. Background technique

The IP Multimedia Core Subsystem (IMS) is an IP-based network architecture proposed by the 3rd Generation Partnership Project (3GPP) to build an open and flexible business environment. Multimedia applications can provide users with rich multimedia services.

In the IMS service system, the control layer and the service layer are separated. The control layer does not provide specific services, and only provides the necessary triggering, routing, and accounting functions to the service layer.

The service triggering and control functions in the control layer are performed by the Call Session Control Function (CSCF, Call Session Control Function). The call session control functions mainly include: a proxy call session control function entity (P-CSCF, Proxy-CSCF), an inquiry call session control function entity (I-CSCF, Interrogating-CSCF), and a service call session control function entity (S-CSCF, Serving-CSCF) three types, of which the S-CSCF function is required, and the I-CSCF is optional.

The service layer is composed of a series of application servers (AS, Application Server), which can provide specific service services. The AS can be an independent entity or exist in the S-CSCF.

The control layer (S-CSCF) controls the service trigger according to the subscription information of the user, invokes the service on the AS, and implements the service function. The end-to-end device in the session is called User Equipment (UE) and is responsible for interaction with the UE user. The UE has multiple ways of accessing the network, including accessing the network through the 3GPP packet switching (PS, Packet Switch) domain, or accessing the network through other non-3GPP PS domains, or even through circuit switching (CS, Circuit Switch). Domain access network, etc. When an IMS user accesses and initiates a call in the CS domain, its call signaling needs to be routed to the IMS domain to which the user belongs, thereby providing services to the user.

Figure 1 is a flow chart of an existing IMS user in the CS call. As shown in Figure 1, the application scenario in which the IMS user equipment UE-1 calls UE-2 in the CS domain is described.

Step 101: UE-1 calls UE-2 in the CS domain, for example, the UE A number A is used to send a CS signaling establishment (SETUP) message.

Step 102: The call message arrives at the Mobile Switching Center (MSC), and the MSC requests the IMS routing number from the Home Network, ie, the Service Centralization and Continuity Application Server (SCC AS). The request message is sent by the IN (Intelligent Network) or CAMEL (Customized Application for Mobile Network Enhanced Logic), carrying the number A.

Step 103: The request message arrives at the SCC AS, and the SCC AS returns the IMS routing number B, and the number B points to the SCC AS.

Step 104: The MSC redirects the call to the number B, that is, the call is sent by the called party B, for example, an initial address message (IAM, Initial Address Message) message or an INVITE message is sent.

Step 105: Since the number B is the number of the home network, the CS signaling is routed to the Media Gateway Control Function (MGCF) of the home network, and the MGCF translates the CS signaling into the IMS signaling and then forwards the message. The IMS call message finally reaches the SCC AS through the CSCF route.

Step 106, since the number B is a redirect number assigned to the number A, the SCC AS The number A can be obtained by the called number B.

Step 107: The SCC AS redirects the received call message to the UE A number A and then forwards it.

In steps 108-109, UE-2 answers the call and returns an IMS response message, such as sending a "200 OK" message, and the message arrives at the MGCF through the CSCF and the SCC AS.

Steps 110-111, the MGCF translates the IMS response message into a response message of the CS signaling, such as an answer message (ANM, Answer Message) or "200 OK", and then forwards it to the MSC.

Step 111: The MSC sends a response message to the UE-1.

So far, a call is established between UE-1 and UE-2, wherein the CS media path is connected from the visited network of UE-1 to the home network of UE-1.

The shortcoming of the prior art is that even if the visited network of the UE-1 has the IMS network access capability, the UE-1 initiated call in the CS domain does not use the IMS network access capability of the visited network of the UE-1, thereby Long-distance link resources occupying CS. Summary of the invention

In view of the above, the main object of the present invention is to provide a method and system for accessing a circuit switched domain call through a visited IMS access point, and can make a call for a call initiated by the CS domain through the visited IMS access point.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A method for a circuit switched domain call to be accessed by a visited IMS access point, including:

The MSC or the UE queries the SCC AS for the calling party's visited IMS control point ( Visited IMS)

Control Point (referred to as VICP) information, or obtained according to the number or logo of the calling user

VICP information; the MSC or the UE sends a call message through the VICP corresponding to the VICP information.

Preferably, the number of the calling user carries VICP information, or the identifier of the calling user includes VICP information. Preferably, the VICP information is a VICP number, and/or a VICP identification, and/or an index for finding a VICP.

Preferably, the requesting the SCC AS to query the VICP information of the calling user is specifically:

The MSC sends the number or identification information of the calling user by using an intelligent network or CAMEL mode, or the MSC or the UE sends the number or identification information of the calling user by using IMS signaling, where the calling user After the number or the identification information arrives at the SCC AS, the SCC AS determines the VICP information of the calling user according to the number or identification information of the calling user, and returns the VICP information to the MSC or the UE.

Preferably, the requesting, by the UE, the VCC information of the calling user to the SCC AS is: the UE sends a message to the SCC AS by using the IMS signaling, the message passes the VICP; the message arrives at the SCC AS Thereafter, the SCC AS returns information of the VICP to the UE.

Preferably, the sending, by the MSC or the UE, the call message by using the VICP corresponding to the VICP information is:

Sending, by the MSC or the UE, a call message targeting the VICP number or identifier, or sending a call message requesting to pass the VICP;

After receiving the call message, the VICP forwards the call message.

Preferably, after the SCC AS receives the call message, and determines that the target of the call message is the VICP, the SCC AS redirects the target of the call message to a called user number or identifier.

Preferably, the VICP is an Access Transfer Control Function (ATCF), or a P-CSCF, or an Interconnection Border Control Function (IBCF), or an MSC with an IMS access function.

A system in which a circuit switched domain call is accessed by a visited IMS access point, including an MSC, a VICP, and an SCC AS; The MSC is configured to query the SCC AS for the VICP information of the calling user, or obtain the VICP information according to the number or identifier of the calling user, and send the call message by using the VICP corresponding to the VICP information;

VICP, used to forward the call message.

Preferably, the system further includes a UE, configured to query the SCC AS for the VICP information of the calling user, or obtain the VICP information according to the number or identifier of the calling user, and send the VICP information corresponding to the VICP information. Call the message.

Preferably, the SCC AS is configured to: after receiving the call message, determine that the target of the call message is the called user number or identifier when the target of the call message is the VICP.

Preferably, the MSC further sends the number or identification information of the calling user by using an intelligent network or CAMEL mode, or the MSC or the UE sends the number or identification information of the calling user by using IMS signaling;

After the number or the identification information of the calling user arrives at the SCC AS, the SCC AS further determines the VICP information of the calling user according to the number or the identification information of the calling user, and returns the information of the VICP to the office. Said MSC or UE.

Preferably, the VICP is an ATCF, or a P-CSCF, or an IBCF, or an MSC having an IMS access function.

In the present invention, the MSC or the UE queries the SCC AS for the VICP information of the calling user, or obtains the VICP information according to the number or the identification information of the calling user, and the MSC or the UE sends the call message through the VICP corresponding to the VICP information. . In the present invention, when the UE initiates a call in the CS domain, the UE can use the IMS access capability of the visited place, and the occupation of the CS long-distance link resource is reduced to some extent. DRAWINGS

1 is a flow chart of an existing IMS user at the time of CS call; 2 is a flowchart of Embodiment 1 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention;

3 is a flowchart of Embodiment 2 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention;

4 is a flowchart of Embodiment 3 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention;

FIG. 5 is a flowchart of Embodiment 4 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention. The basic idea of the present invention is that the MSC or the UE queries the SCC AS for the VICP information of the calling user, or obtains the VICP information according to the number or the identification information of the calling user, and the MSC or the UE passes the The VICP corresponding to the VICP information sends a call message. The present invention will be further described in detail below with reference to the accompanying drawings.

Embodiment 1

2 is a flowchart of Embodiment 1 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention. As shown in FIG. 2, in this example, the calling user equipment is UE-1 and the called user equipment. For UE-2, where the user of UE-1 is an IMS user, a call to UE-2 is initiated through the CS domain, and the MSC does not support IMS signaling. The method for accessing a circuit switched domain call of the present example by using a visited IMS access point specifically includes the following steps:

Step 201: The UE-1 calls the UE-2 in the CS domain, for example, the UE A is the SETUP message of the CS signaling, and the network where the UE-1 is located is the visited network. If the UE-1 does not If roaming, the visited network is the home network of UE-1.

Step 202, the SETUP message of the call arrives at the MSC, and the MSC sends the SCC AS to the calling user. Requesting an IMS routing number, for example, sending an request message requesting an IMS routing number in an IN mode or a CAMEL manner, where the request message carries the number A or the identifier of the UE-2 (such as the international mobile terminal identity IMSI or international) Mobile device identification IMEI).

Step 203: After receiving the request message of the IMS routing number, the SCC AS allocates the IMS routing number B to the call according to the number or identifier of the UE-1, and sends the IMS routing number B to the MSC; the number B points to the VICP.

Step 204: After receiving the IMS routing number B, the MSC redirects the current call to the number B, that is, the number B is used to send a call message to the VICP pointed to by the number B, for example, sending the CS signaling to the VICP pointed to by the VICP number B. The IAM message or INVITE message, since the number B is the number pointing to the VICP, the CS signaling will be routed to the VICP. If the call message sent by the MSC to the VICP is an IAM message, the message will be converted into an INVITE message via the MGCF. Then, it is forwarded to the VICP pointed to by the number B. If the call message sent by the MSC is an INVITE message, it can be directly sent to the VICP pointed to by the number B.

Step 205: The VICP sends the call message to the home network of the calling user, for example, an INVITE message that sends IMS signaling, and the INVITE message targets the number B.

Step 206: After receiving the call message sent by the VICP, the CSCF routes the call message to the SCC AS according to the setting of the existing protocol. Since the number B is the redirect number assigned to the number A, the SCC according to the prior art is used. The AS can obtain the number A and/or the called subscriber identity associated with the number A by the called number B.

Step 207: The SCC AS redirects the received call message according to the prior art to the UE A number A or the identifier, and forwards the received call message.

Steps 208~209, UE-2 answers the call, returns an IMS response message, such as sending a "200 OK" message, and the "200 OK" message arrives at VICP through CSCF and SCC AS.

Step 210: The VICP forwards the response message to the MSC, for example, sending a "200 OK" message. If the MSC sends an IAM message, the IAM message is translated into an ANM message by the MGCF and then sent to the MSC.

Step 211: The MSC sends a response message to the UE-1.

So far, a call is established between UE-1 and UE-2. In the present invention, since the CS media path is only in the visited network of UE-1, CS long-distance link resources are not occupied.

Embodiment 2

FIG. 3 is a flowchart of Embodiment 2 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention. As shown in FIG. 3, the application scenario of the present example is: MSC supports IMS signaling, and UE-1 The VICP information is included in the number information (for example, the prefix portion of the number of UE-1 can be used to index VICP), and the IMS user equipment UE-1 calls UE-2 in the CS domain. The method for accessing the circuit-switched domain call of the present example by using the visited IMS access point specifically includes the following steps:

Before the following call processing procedure begins, the MSC may obtain the VICP number and/or identity based on the VICP information contained in the UE-1 number or identity (e.g., global resource identification URI) information (such as the prefix portion of the number information described above).

Step 301: The UE-1 calls the UE-2 in the CS domain, for example, using the number A of the UE-2 as the SETUP message of the CS signaling sent by the called party;

Step 302: The call request arrives at the MSC. If the MSC has not obtained the VICP number and/or the identifier, the MSC obtains the VICP number according to the number of the UE-1 or the VICP information contained in the identification information (such as the prefix portion of the number information described above). / or logo;

Step 303: The MSC converts the call message of the CS signaling into a call message of the IMS signaling, and redirects the VICP to the VICP according to the obtained VICP number or identifier. For example, the INVITE message is sent with the VICP number or the identifier as the target, and the INVITE message is sent. Carrying the called number A, that is, the number of the UE-2, or requesting the call message to pass through the VICP, for example, adding the VICP number or identifier in the Route header field of the call message; Steps 304 to 305, the VICP redirects the call to the UE-2, that is, the INVITE message is sent with the UE-2 as the target, and the call message INVITE message path CSCF and the SCC AS finally reach the UE-2; Steps 306-308, UE-2 Answer Call, return IMS response message, such as sending "200 OK" message, "200 OK" message through CSCF and SCC AS, and forwarded by VICP, and finally arrive at MSC;

Step 309, the MSC sends a response message to the UE-1.

Embodiment 3

4 is a flowchart of Embodiment 3 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention. As shown in FIG. 4, in this example, the calling user equipment is UE-1 and the called user equipment. For UE-2, where the user of UE-1 is an IMS user, a call to UE-2 is initiated through the CS domain, and the MSC supports IMS signaling. The method for accessing the circuit switched domain call of the present example by using the visited IMS access point specifically includes the following steps:

Step 401: The UE-1 calls the UE-2 in the CS domain, for example, the UE A's number A is the SETUP message of the CS signaling sent by the called party. Here, the network where the UE-1 is located is the visited network, if the UE-1 does not If roaming, the visited network is the home network of UE-1.

Step 402: The SETUP message of the call arrives at the MSC, and the MSC sends an IMS call message to the home network of the UE-1. The destination of the call message is the number A of the UE-2, carrying the number or identifier of the UE-1, the call message. After the CSCF arrives at the SCC AS.

Step 403: After receiving the call message, the SCC AS determines the VICP according to the number or identifier of the UE-1, and requests the MSC to resend the call message to pass the VICP, for example, a 305 Use Proxy message for sending IMS signaling, The 305 Use Proxy" message carries the number or logo of the VICP. Step 404: After receiving the retransmission call message, the MSC resends the call message, and requests the call message to pass through the VICP, for example, placing the VICP number or identifier into the Route header field of the call message.

Step 405: The VICP sends the call message to the calling user's home network, for example, forwarding the call message, and the message arrives at the SCC AS through the CSCF.

Step 406: The SCC AS forwards the received call message.

Steps 407~408, UE-2 answers the call and returns an IMS response message, such as sending a "200 OK" message, and the "200 OK" message arrives at the VICP through the CSCF and the SCC AS.

In step 409, the VICP forwards the response message to the MSC, for example, sending a "200 OK" message. Step 410: The MSC sends a response message to UE-1.

Embodiment 4

5 is a flowchart of Embodiment 4 of a method for accessing a circuit switched domain call through a visited IMS access point according to the present invention. As shown in FIG. 5, in this example, the calling user equipment is UE-1 and the called user equipment. For UE-2, where the user of UE-1 is an IMS user, a media connection with UE-2 is established through the CS domain. The method for accessing a circuit switched domain call of the present example by using a visited IMS access point specifically includes the following steps:

Step 501: The UE-1 requests the called number of the subsequent CS call from the SCC AS of the calling user in the IMS domain, and carries the real called number and/or identifier of the subsequent CS call, such as an INVITE message for sending IMS signaling; The network where the UE-1 is located is the visited network. If the UE-1 does not roam, the visited network is the home network of the UE-1.

Step 502: The IMS INVITE request message passes through the VICP (because the VICP is an IMS access point), and the VICP forwards the request message to the calling user's SCC AS. Step 503 to step 504, after receiving the request message, the SCC AS learns that the request message passes through the VICP, and then assigns the called number B of the subsequent CS call to the call, and sends the called number B to the UE through the VICP; the number B points to the VICP, SCC AS The called number C of the subsequent CS call can also be assigned, and the number C points to the SCC AS.

Step 505: If the SCC AS performs the operation of assigning the number B, the UE-1 calls the called number B in the CS domain, for example, a SETUP message for transmitting CS signaling. If not, the UE-1 is based on the number or identifier of the UE-1. The VICP information contained in the information (such as URI) (such as the prefix portion of the number information described above) obtains the number B of the VICP and calls the called number B in the CS domain.

Step 506: The SETUP message of the call arrives at the MSC, and the MSC forwards the call to the VICP. In step 507, the VICP forwards the call to the SCC AS.

Step 508: The SCC AS redirects the received call message to the number A or identifier of the UE-2 according to the prior art, and forwards the received call message.

Step 509~Step 510, UE-2 answers the call and returns an IMS response message, such as sending a "200 OK" message, and the "200 OK" message arrives at the VICP through the CSCF and the SCC AS.

Step 511: The VICP forwards the response message to the MSC, for example, sends a "200 OK" message. If the MSC sends an IAM message, the IAM message is translated into an ANM message by the MGCF, and then sent to the MSC.

Step 512: The MSC sends a response message to the UE-1.

In the present invention, the VICP in the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment is specifically an ATCF, or a P-CSCF, or an IBCF, or an MSC having an IMS access function.

The present invention also describes a system in which a circuit switched domain call is accessed through a visited IMS access point, including an MSC, a VICP, a UE, and an SCC AS. The foregoing network element has the following functions, and There are slight differences between the corresponding network elements in the network, which are described in detail below.

The MSC or the UE is configured to query the SCC AS for the VICP information of the calling user, or obtain the VICP information according to the number or the identification information of the calling user, and send a call message through the VICP corresponding to the VICP information.

The VICP is configured to forward the call message.

The SCC AS is configured to: after receiving the call message, determine that the target of the call message is the called user number or identifier when the target of the call message is the VICP.

The MSC further sends a calling number or identification information by using an intelligent network mode or a CAMEL mode, or the MSC or the UE sends the calling number or the identification information by using the IMS signaling; the calling number or the identification information reaches the After the SCC AS, the SCC AS further determines the VICP information of the calling user according to the calling number information, and returns VICP information to the MSC or the UE.

The above VICP is ATCF, or P-CSCF, or IBCF, or an MSC with IMS access.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for a circuit switched domain call to be accessed by a visited IMS access point, the method comprising:

The mobile switching center MSC or the user equipment UE queries the service continuous and centralized application server (SCC AS) for the visited IMS control point VICP information of the calling user, or obtains VICP information according to the number or identity of the calling user; Or the UE sends a call message by using a VICP corresponding to the VICP information.

2. The method according to claim 1, wherein the number of the calling user carries VICP information, or the identifier of the calling user includes VICP information.

The method according to claim 1 or 2, wherein the VICP information is a VICP number, and/or a VICP identifier, and/or an index for finding a VICP.

The method according to claim 1, wherein the MSC or the UE queries the SCC AS for VICP information of the calling user:

The MSC sends the number or identification information of the calling user by using an intelligent network or a CAMEL manner, or the MSC or the UE sends the number or identification information of the calling user by using IMS signaling;

After the number or the identification information of the calling user arrives at the SCC AS, the SCC AS determines the VICP information of the calling user according to the number or the identification information of the calling user, and returns the VICP information to the MSC or the office. Said UE.

The method according to claim 1, wherein the requesting, by the UE, the VCC information of the calling user to the SCC AS is specifically:

The UE sends a message to the SCC AS by using the IMS signaling, and the message passes the VICP. After the message arrives at the SCC AS, the SCC AS returns the information of the VICP to the UE.

6. The method according to claim 1, wherein the MSC or the UE The sending a call message by using the VICP corresponding to the VICP information is: or sending a call message requesting to pass the VICP;

After receiving the call message, the VICP forwards the call message.

The method according to claim 6, wherein, after the SCC AS receives the call message, and determines that the target of the call message is the VICP, the SCC AS redirects the call message. The target is the called user number or logo.

8. The method according to claim 1, wherein the VICP is an access transfer control function entity ATCF, or a proxy call session control function P-CSCF entity, or an interactive border control function IBCF entity, or has IMS access. Functional MSC.

A system in which a circuit-switched domain call is accessed by a visited IMS access point, and includes MSC, VICP, and SCC AS;

The MSC is configured to query the SCC AS for the VICP information of the calling user, or obtain the VICP information according to the number or identifier of the calling user, and send the call message through the VICP corresponding to the VICP information;

VICP, used to forward the call message.

10. The system according to claim 9, further comprising a UE, configured to query the SCC AS for VICP information of the calling user, or obtain VICP information according to the number or identifier of the calling user. And sending a call message through the VICP corresponding to the VICP information.

The system according to claim 10, wherein the SCC AS is configured to: after receiving the call message, determining that the target of the call message is the VICP, redirecting the call message The target is the called subscriber number or logo.

The system according to claim 9 or 10, wherein the MSC further transmits the number or identification information of the calling user by using an intelligent network mode or a CAMEL mode, or the MSC or the UE uses IMS signaling. Sending the number or identification information of the calling user; After the number or identification information of the calling user arrives at the SCC AS, the SCC AS further determines the VICP information of the calling user according to the number or identification information of the calling user, and determines the VICP. The information is returned to the MSC or UE.

The system according to any one of claims 9 to 12, wherein the VICP is an ATCF, or a P-CSCF, or an IBCF, or an MSC having an IMS access function.